Wait-and-see policy for clinical complete responders after chemoradiation for rectal cancer

Combined tumor-associated microbiome and immune gene expression profiling predict response to neoadjuvant chemo-radiotherapy in locally advanced rectal cancer

Locally advanced rectal cancer (LARC) is treated with neoadjuvant chemo-radiotherapy (nCRT) followed by surgery. A minority of patients show complete response (CR) to nCRT and may avoid surgery and its functional consequences. Instead, most patients show non-complete response (non-CR) and may benefit from additional treatments to increase CR rates. Reliable predictive markers are lacking. Aim of this study was to identify novel signatures predicting nCRT responsiveness. We performed a combined analysis of tumor-associated microbiome and immune gene expression profiling of diagnostic biopsies from 70 patients undergoing nCRT followed by rectal resection, including 16 with CR and 54 with non-CR. Findings were validated by an independent cohort of 49 patients, including 7 with CR and 42 with non-CR. Intratumoral microbiota significantly differed between CR and non-CR groups at genus and species level. Colonization by bacterial species of Ruminococcus genera was consistently associated with CR, whereas abundance of Fusobacterium, Porhpyromonas, and Oscillibacter species predicted non-CR. Immune gene profiling revealed a panel of 59 differentially expressed genes and significant upregulation of IFN-gamma and -alpha response in patients with CR. Integrated microbiome and immune gene profiling analysis unraveled clustering of microbial taxa with each other and with immune cell-related genes and allowed the identification of a combined signature correctly identifying non-CRS in both cohorts. Thus, combined intratumoral microbiome-immune profiling improves the prediction of response to nCRT. Correct identification of unresponsive patients and of bacteria promoting responsiveness might lead to innovative therapeutic approaches based on gut microbiota pre-conditioning to increase nCRT effectiveness in LARC.

Real-World Long-Term Outcomes of Operated and Non-Operated Rectal Cancer in the Elderly: A 14-Year Retrospective Multicentre Study

OBJECTIVE

Surgical resection is the cornerstone of rectal cancer treatment. Following neoadjuvant chemoradiotherapy (nCRT), many patients undergo surgery. Another group of patients may not undergo surgery for various reasons, regardless of nCRT response. This study investigates the differences in clinical characteristics and long-term oncological outcomes of operated and non-operated elderly rectal cancer patients.

METHODS

This multicentre observational retrospective cohort analysis included 296 elderly patients (169 surgery, 127 non-surgical) treated at three tertiary cancer centres in Turkey between January 2010 and April 2024. Clinicopathologic features and survival outcomes were compared between groups.

RESULTS

Patients in the surgery group were younger (p < 0.000) and had better performance scores (p < 0.000). There were no differences in initial clinical (c) T stages or cM stages; however, cN2 patients were more prevalent in the surgical group and cN1 patients were more prevalent in the non-surgical group (p = 0.010). No differences in radiotherapy treatment schedules were observed among the groups. The surgical group received more concurrent (p = 0.046) and adjuvant (p < 0.000) chemotherapy. Patient refusal (63.8%) was the most common reason among non-surgical patients. The surgery group showed better overall survival (OS) (median, 99 vs. 33 months) (p < 0.000), local recurrence-free survival (LRFS) (97.8% vs. 65.8% at 3 years, p < 0.000), and distant metastasis-free survival (DMFS) (80.3% vs. 73.3% at 3 years, p = 0.022).

CONCLUSION

This study shows that elderly rectal cancer patients without surgery had poor survival and tumour control. Surgical resection in rectal cancer is very important and should be strongly recommended for all medically suitable elderly patients.

Phase II trial of organ preservation program using short-course radiation and FOLFOXIRI for rectal cancer (SHORT-FOX): Two-Year primary outcome analysis

BACKGROUND AND PURPOSE

As patients with rectal cancer with clinical complete response (cCR) after neoadjuvant therapy may be safely spared Total Mesorectal Excision (TME), strategies to maximize cCR are needed.

MATERIALS AND METHODS

We conducted a single-arm phase II study to determine whether dose-escalated short-course radiotherapy (25 Gy/5 fractions + 5 Gy/1 fraction boost) followed by eight cycles of FOLFOXIRI increased cCR rates among adult patients with > T2N0M0 or low T2N0 rectal cancer.

RESULTS

Between 2020 and 2023, we enrolled 37 patients, of whom 27 (73 %) had at least one high-risk feature (cT4, extramural vascular invasion [EMVI], N2, threatened circumferential resection margin, positive lateral node). At primary endpoint assessment, nine (24 %) patients had cCR on both endoscopy and MRI, and pursued organ preservation (OP). Fourteen (38 %) patients had cCR only on endoscopy, nine of whom pursued OP. Of the 18 patients who pursued OP, nine had local regrowth at two years from radiotherapy start, with two-year TME-free survival of 26 %. Baseline factors significantly associated with not achieving OP included age < 50 years and T4 disease. At mid-treatment restaging, patients who achieved OP were significantly less likely to have persistent node positivity, EMVI, and endoscopically visible tumor. Grade 3+ adverse events at least possibly attributed to chemotherapy and radiotherapy occured in 51% and 43% of patients, respectively.

CONCLUSION

Short-course radiotherapy with a boost followed by FOLFIXIRI results in OP in one-quarter of patients with high-risk rectal cancer, with poorer response among younger patients and T4 disease. Mid-treatment response may help guide timely decision-making regarding treatment.

Neoadjuvant chemotherapy and chemoradiotherapy versus chemoradiotherapy alone in high-risk locally advanced rectal cancer: A retrospective comparison of two Dutch tertiary referral centres

INTRODUCTION

The effect of neoadjuvant chemotherapy and chemoradiotherapy in patients with locally advanced rectal cancer, at increased risk of failing current treatment regimens, is unknown. This study compared the complete response rate and long-term survival of these patients treated with or without neoadjuvant chemotherapy prior to chemoradiotherapy.

MATERIALS AND METHODS

Patients with high-risk locally advanced rectal cancer, who were surgically treated or entered a watch and wait approach after neoadjuvant chemoradiotherapy with or without neoadjuvant chemotherapy in Erasmus Medical Centre or Catharina Hospital between 2016 and 2020, were retrospectively identified. High-risk was defined as the presence of tumour invasion into the mesorectal fascia, grade 4 extramural venous invasion, enlarged lateral lymph nodes, or tumour deposits. The primary endpoint was complete response rate, which was defined as a histopathological complete response or a sustained (during 12 months) clinical complete response. Long-term oncological outcomes were evaluated based on Kaplan-Meier and Cox regression survival analyses.

RESULTS

The neoadjuvant chemotherapy group consisted of 64 patients, of whom 61 (95.3 %) were treated with chemotherapy prior to chemoradiotherapy, the chemoradiotherapy group of 194 patients. The complete response rates were 25.0 % and 9.8 %, respectively (P = 0.002). The estimated 3-year overall survival was 92.2 % in the neoadjuvant chemotherapy group versus 66.9 % in the chemoradiotherapy group.

CONCLUSION

Excellent oncological outcomes were observed in patients with high-risk locally advanced rectal cancer selected during a multidisciplinary team (MDT) meeting for neoadjuvant chemotherapy and chemoradiotherapy. The actual difference with patients treated with chemoradiotherapy alone should be investigated in prospective trials. Pretreatment referral to expert MDTs is encouraged.

Comparison of immunotherapy based total neoadjuvant therapy or standard neoadjuvant chemoradiation for locally advanced rectal cancer: a multi-institutional retrospective study

Background

Combining radiation therapy with immunotherapy produces a synergistic effect in patients with microsatellite stable/mismatch repair-proficient (MSS/pMMR) locally advanced rectal cancer (LARC). This study aimed to evaluate the long-term outcomes and safety of immunotherapy combined with long-course chemoradiotherapy (ICIs + nCRT) versus immunotherapy combined with total neoadjuvant therapy (ICIs + TNT).

Methods

This retrospective study collected clinical data of adult patients with clinical T3-4 and/or N1 rectal adenocarcinoma who underwent ICIs + TNT or ICIs + nCRT followed by curative surgery at four medical centers between March 2020 and August 2021. The study compared clinical efficacy, disease-free survival (DFS), overall survival (OS) at 3 years postoperatively, and adverse event.

Results

Among 211 enrolled patients, 89 (42%) received ICIs + TNT, while 122 (58%) underwent ICIs + nCRT, with a median age of 56.0 years (range, 20.0-75.0 years). The ICIs + TNT group had a higher median number of resected lymph nodes (15.0 [range, 4.0-37.0] vs. 13.0 [range, 3.0-33.0], P=0.028) compared to the ICIs+nCRT group. However, the groups had no substantial difference in median operative time. The pathological complete response (pCR) rate was 49.4% (44/89, 95% confidence interval [CI] 39.8%-61.3%) in the ICIs + TNT group compared to 35.3% (43/122, 95% CI 26.8%-44.4%) in the ICIs + nCRT group, respectively, with significant difference (P=0.039). After adjusting for potential confounders, the 3-year DFS rates were comparable between the two groups (84.3% vs. 81.9%; P=0.620), as were the OS rates (94.0% vs. 91.1%; P=0.634). Factors independently associated with poorer DFS included age ≤50 years (P=0.044) and a neoadjuvant rectal (NAR) score ≥8 (P=0.008). Similarly, patients aged ≤50 years (P=0.025) exhibited a trend toward worse OS than those older than 50 years. The safety profiles of the two treatment groups were similar.

Conclusions

Overall, ICIs + TNT demonstrated therapeutic efficacy and a safety profile comparable to ICIs + nCRT in patients with LARC and MSS/pMMR status. Although ICIs + TNT achieved numerically higher downstaging rates, it was not associated with improved survival outcomes. These findings underscore the importance of refining patient selection criteria and making judicious treatment decisions to enhance the prognosis of individuals with rectal cancer.

Assessment of Immunoscore, MRI Tumor Regression Grade, and Neoadjuvant Rectal Score in Predicting Pathologic Response in Locally Advanced Rectal Cancer in the Averectal Study

Background/Objectives: Predictive tools are needed to assess the response to treatment and guide treatment decisions for locally advanced rectal cancer (LARC). This study explores the value of combining the immunoscore (IS) and magnetic resonance imaging tumor regression grade (mrTRG) with pathologic and radiologic neoadjuvant rectal (NAR) scores in predicting pathologic complete response (pCRs). Methods: The scores were assessed for patients with LARC enrolled in the Averectal study (NCT03503630), who received five fractions of short-course radiotherapy, followed by six cycles of mFOLFOX-6 plus avelumab, and total mesorectal excision. The IS was calculated using the mean density percentiles of CD3- and CD8-positive T-cells on baseline biopsy samples. Baseline and post-treatment MRIs were reviewed to measure the mrTRG. NAR scores were calculated using the pre-treatment T stage and post-treatment pathologic and radiologic N and T stages. Results: Fifteen out of thirty-five patients whose data were available achieved pCR (42.8%), and seven out of fourteen patients with mrTRG = 1 (complete response) attained pCR. In patients with both a mrTRG = 1 and high IS, the pCR rate was 66.7% (6/9). All of the patients who achieved pCR had a low or intermediate pathologic NAR score with a significant correlation between pCR and pathologic NAR scores (p < 0.0001). Both pathologic and radiologic NAR scores were correlated with overall survival and disease-free survival. Conclusions: The IS can supplement the mrTRG to better predict TNT outcomes, along with the use of the NAR score. This combination could potentially help with patient selection for non-operative management and guide treatment strategies for those with different recurrence risks.

Outcomes of Postchemoradiotherapy Watch-and-Wait Strategy in Patients With Rectal Cancer: A 20-Year, Single-Center Study

BACKGROUND AND OBJECTIVES

The watch-and-wait (WW) strategy is a nonsurgical alternative for patients with rectal cancer exhibiting an excellent response to chemoradiotherapy. Studies on the WW strategy have primarily investigated 5-year oncological outcomes; few have focused on longer-term outcomes or the optimal patient selection approach for this therapeutic strategy.

METHODS

This retrospective study enrolled patients with locally advanced rectal adenocarcinoma who had achieved complete response after chemoradiotherapy. Patients who achieved pathological complete response were categorized into a control group (n = 95) and those who achieved clinical complete response and were managed using the WW strategy were categorized into a case group (n = 33). Kaplan-Meier estimates were calculated for the between-group comparison of survival.

RESULTS

The median follow-up duration was 89 months. Compared with the control group, the case group exhibited improved long-term sphincter preservation, particularly for low-lying tumors (p = 0.032), and inferior nonlocal-regrowth disease-free survival (p = 0.007). Within the case group, patients achieving a complete response by positron emission tomography exhibited 5-year survival rates similar to those achieving a complete endoscopic response.

CONCLUSION

The WW strategy is associated with improved sphincter preservation but worse nonlocal-regrowth disease-free survival. The potential of PET in patient selection for this strategy deserves further investigation.

Reliability of rectal MRI radiomic features: Comparing rectal MRI radiomic features across reader expertise levels, image segmentation technique, and timing of rectal MRI in patients with locally advanced rectal cancer

OBJECTIVES

To assess the reliability of rectal MRI radiomic features across reader expertise level, image segmentation technique, and timing of rectal MRI.

MATERIAL AND METHODS

This retrospective single-institutional study included consecutive patients with rectal adenocarcinoma who underwent total neoadjuvant therapy from January 2018 to June 2018. Baseline and restaging rectal MRI T2-weighted images were segmented independently by six radiologists (two fellows, two non-rectal radiologists, and two rectal radiologists). Four segmentation strategies were used and varied by image segmentation technique and timing of rectal MRI: (a) baseline volume of interest (VOI), (b) baseline region of interest (ROI), (c) restaging VOI, and (d) restaging ROI. Inter-reader agreement on each extracted radiomic feature was evaluated using the intra-class correlation coefficient (ICC).

RESULTS

Among 24 patients (16 men; median age, 56 years [interquartile range: 49-62]), 1,595 radiomic features were extracted. Baseline VOI segmentation achieved the highest inter-reader agreement rate, with 68 % (1,079/1,595) of radiomic features having an ICC > 0.7. Restaging ROI segmentation achieved the worst inter-reader agreement rate, with only 26 % (415/1,595) of radiomic features having an ICC > 0.7. First-order statistics and Gray Level Co-occurrence Matrix (GLCM) feature subgroups showed high inter-reader agreement rates, and the application of 'Square Root' and 'LOG Sigma' filters resulted in improved inter-reader agreement rates relative to original images. The expertise level of radiologists performing the segmentations did not affect the distribution of inter-agreement rates according to image segmentation technique or timing of rectal MRI.

CONCLUSIONS

Radiomic features were more reliable when extracted from baseline (vs. restaging) rectal MRIs and using 3D volume of interest (vs. 2D region of interest) segmentation, independent of the expertise level of the radiologists performing the segmentation.

CLINICAL RELEVANCE STATEMENT

Radiomic studies on rectal MRI employ various segmentation strategies and few assess their impact on reproducibility. Establishing the optimal segmentation method enhances radiomics model generalizability, potentially bridging the gap in clinical translation and improving clinical management of patients.

Rectal cancer approach strategies after neoadjuvant treatment - a systematic review and network meta-analysis

BACKGROUND AND AIMS

An increasing number of patients with rectal cancer who respond well to neoadjuvant chemoradiotherapy (nCRT) are being considered for organ preservation programs. However, due to the lack of high-level evidence, the survival outcomes of the organ preservation programs are still full of controversy and uncertainty.

METHODS

To assess the effects of total mesorectal excision (TME) surgery, watch-and-wait (W&W), and local excision (LE) on long-term outcomes after nCRT, we searched PubMed, Embase, and Web of Science for articles published between 1 January 2010, and 31 December 2023.

RESULTS

We found 7029 pieces of literature, of which 26 studies met the inclusion criteria, and recruited 2778 participants in the network meta-analysis. Risk of bias assessment showed that most included studies had a low risk of bias. Low-certainty evidence suggests that the TME group was significantly superior to all other interventions for the 2-year local regrowth rate. (W&W group [OR, 0.20; 95% CI, 0.12-0.35], LE group compared with TME group [3.00; 1.60-5.80]). There was no significant difference in the 2-year local regrowth rate between W&W and LE group (OR, 0.60; 95% CI, 0.32-1.20). There was high to moderate certainty evidence that at 3 years, the W&W group had a significant advantage in overall survival compared with the TME group (OR, 0.37; 95% CI, 0.09-0.95). After 5 years, no significant difference in overall survival was found between the 3 treatment modalities.

CONCLUSIONS

We concluded that TME achieved the most significant reduction in 2-year local regrowth rates. However, the W&W strategy and LE demonstrated noninferiority to TME in long-term survival outcomes.

A randomized phase II/III trial of rosuvastatin with neoadjuvant chemo-radiation in patients with locally advanced rectal cancer

Aim

Statins have been shown to improve the possibility of a pathological complete response (pCR) in patients with locally advanced rectal cancer when given in combination with neo-adjuvant chemo-radiation (NACTRT) in observational studies. The primary objective of this phase II randomized controlled trial (RCT) is to determine the impact of rosuvastatin in improving pCR rates in patients with locally advanced rectal cancer who are undergoing NACTRT. The secondary objectives are to compare adverse events, postoperative morbidity and mortality, disease-free survival (DFS), and overall survival in the two arms and to identify potential prognostic and predictive factors determining outcomes. If the study is positive, we plan to proceed to a phase III RCT with 3-year DFS as the primary endpoint.

Methods

This is a prospective, randomized, open-label phase II/III study. The phase II study has a sample size of 316 patients (158 in each arm) to be accrued over 3 years to have 288 evaluable patients. The standard arm will receive NACTRT while the intervention group will receive 20 mg rosuvastatin orally once daily along with NACTRT for 6 weeks followed by rosuvastatin alone for 6-10 weeks until surgery. All patients will be reviewed after repeat imaging by a multidisciplinary tumor board at 12-16 weeks after starting NACTRT and operable patients will be planned for surgery. The pathological response rate, tumor regression grade (TRG), and post-surgical complications will be recorded.

Conclusion

The addition of rosuvastatin to NACTRT may improve the oncological outcomes by increasing the likelihood of pCR in patients with locally advanced rectal cancer undergoing NACTRT. This would be a low-cost, low-risk intervention that could potentially lead to the refinement of strategies, such as "watch and wait", in a select subgroup of patients.

Clinical trial registration

Clinical Trials Registry of India, identifier CTRI/2018/11/016459.

No operation after short-course radiotherapy followed by consolidation chemotherapy in locally advanced rectal cancer (NOAHS-ARC): study protocol for a prospective, phase II trial

PURPOSE

Organ preservation through a watch-and-wait (W&W) strategy has become a viable option for select rectal cancer patients with clinical complete responses (cCR) to total neoadjuvant therapy (TNT). This approach limits the morbidity associated with multimodal treatment. However, the optimal treatment strategy and predictors of treatment response are still unresolved. Rectal cancer incidence is rising, particularly in developing countries, and the disease is a major public health concern in Chile. Prior to the no operation after short-course radiotherapy followed by consolidation chemotherapy in locally advanced rectal cancer (NOAHS-ARC) trial, TNT-based treatments and W&W programs had not been implemented in Chile.

METHODS/DESIGN

This single-arm, multicenter, phase II prospective trial, conducted in Santiago, Chile, will enroll patients with stage II/III rectal adenocarcinoma. Treatment involves induction short-course radiotherapy (25 Gy in 5 fractions) followed by consolidation chemotherapy (FOLFOX × 9 or CAPOX × 6 cycles). The response will be assessed 4-8 weeks after chemotherapy completion. Patients achieving cCR will be offered W&W, while those with incomplete responses will undergo total mesorectal excision. The primary endpoint is the rate of complete tumor response, combining pathologic complete responses (pCR) and sustained cCR (> 1 year), compared to a matched cohort treated with neoadjuvant chemoradiation alone. The trial aims to recruit 48 patients, assuming a combined pCR/sustained cCR rate of 12%. Quality of life measures will be assessed, and a biorepository of tissue and plasma samples will be established for future research, alongside serial endoscopic and MRI images.

DISCUSSION

NOAHS-ARC seeks to advance organ preservation strategies in rectal cancer while pioneering TNT and W&W protocols in Chile. The study will also focus on functional outcomes and provide valuable data for improving patient care both locally and globally.

TRIAL REGISTRATION

ClinicalTrials.gov identifier NCT04864067. Registered on April 28, 2021.

Total neoadjuvant treatment, non-operative management and radiotherapy-free strategies: New approaches for the management of proficient mismatch repair/microsatellite stable locally advanced rectal cancer. A narrative review and evidence-based algorithm

In recent years, new therapeutic approaches have emerged in addition to classical neoadjuvant (chemo)radiotherapy for the treatment of locally advanced rectal cancer (LARC): total neoadjuvant treatment, non-operative management, and radiotherapy-free strategy. While the introduction of these approaches in a relatively short timeframe has quickly increased our therapeutic armamentarium, on the other hand it has complicated the decision-making process regarding the choice of the most appropriate treatment strategy for each patient with LARC. Therefore, a tool to interpret the evidence from clinical trials and to translate them into daily practice is highly demanded. In the present review, we address how these new developments are changing the multimodal treatment of LARC and offer an algorithm to integrate them into clinical practice.

Phase 2, Multicenter, Open-label, Nonrandomized Study of Neoadjuvant Chemotherapy Liposomal Irinotecan With 5-Fluorouracil, Leucovorin, and Oxaliplatin, Followed by Chemoradiotherapy in Patients With Rectal Cancer in a Watch-and-Wait Program

OBJECTIVE

To evaluate the efficacy of neoadjuvant chemotherapy combination with liposomal irinotecan, 5-fluorouracil, leucovorin, and oxaliplatin in patients with locally advanced rectal cancer.

METHODS

This was a phase 2, nonrandomized, multicenter study in adults with stage II or III rectal cancer and an Eastern Cooperative Oncology Group performance status of 0 to 1. Total neoadjuvant therapy (TNT) consisted of neoadjuvant chemotherapy combination with liposomal irinotecan (60 mg/m 2 ), oxaliplatin (60 mg/m 2 ), leucovorin (400 mg/m 2 ), and fluorouracil (2400 mg/m²), followed by chemoradiotherapy [ie, capecitabine (825 mg/m 2 ) and radiotherapy according to the standard of care]. The primary efficacy endpoint was the proportion of patients who achieved clinical complete response (cCR), defined as the normalization of pelvic magnetic resonance imaging, rectoscopy, computed tomography scan, and tumor markers.

RESULTS

The median follow-up was 32.3 months. Of the 30 patients who underwent TNT and were evaluated, 6 (20.0%; 95% CI: 5.2%-34.8%) patients achieved a cCR. There were no deaths. The median disease-free survival (DFS) for patients with cCR was not reached after a follow-up of 32 months; the 1-year DFS rate was 90.0% (95% CI: 71.0%-100%), and the 2-year and 3-year DFS rates were 80.0% (95% CI: 55.0%-100%). No grade ≥4 adverse events (AEs) were observed. Grade 3 AEs occurred in 18 patients (60%), most frequent was diarrhea (n = 9, 30%). Eleven (36.7%) patients experienced serious AEs, with diarrhea being the most frequent (n = 6, 20.0%).

CONCLUSION

TNT with 5-fluorouracil, leucovorin, and oxaliplatin and chemoradiation is a safe and effective therapeutic alternative for the management of locally advanced rectal cancer.

Watch-and-Wait Approach Following Neoadjuvant Chemo-Radiotherapy for Locally Advanced Rectal Cancer: A Retrospective Single-Center Cohort Study

BACKGROUND AND OBJECTIVES

The watch-and-wait (WW) strategy in patients after complete clinical response (cCR) following chemoradiotherapy for locally advanced rectal cancer (LARC) offers the option of organ preservation. The aim of this study was to assess the oncological outcomes of WW patients treated and followed up in a German referral cancer center.

METHODS

In this retrospective study, we analyzed the clinical records of consecutive patients with LARC who underwent neoadjuvant radiotherapy/chemoradiotherapy at our institution between January 2020 and December 2023 and received non-operative management after cCR.

RESULTS

A total of 30 patients undergoing WW for LARC were included. After a median follow-up of 17 months (SD = 10 months), local regrowth occurred in four patients (4/30, 13.3%), and one patient (1/30, 3.3%) developed distant metastasis. No predictor for tumor regrowth could be identified based on radiological findings at diagnosis, including cT4 and/or cN2, involvement of the mesorectal fascia, extramural vascular invasion or infiltration of the anal sphincter/levator. All patients with local regrowth were successfully surgically treated (R0 resection).

CONCLUSION

Nonoperative management for patients with cCR after neoadjuvant therapy for LARC proved to be safe. R0 resection was successfully achieved in all patients who underwent salvage surgery.

A new treatment strategy for mid-low rectal cancer patients exhibiting a clinical complete or near-complete response to neoadjuvant chemoradiotherapy: Transanal endoscopic microsurgery --A multicenter prospective case-control clinical trial by MONT-R

BACKGROUND

Total mesorectal excision is the standard surgery for locally advanced rectal cancer (LARC) after neoadjuvant chemoradiotherapy (nCRT), but it may lead to high complication rates and poor quality of life. This study evaluates whether transanal endoscopic microsurgery (TEM), as a partial resection procedure, can enhance quality of life for clinical complete response (cCR) or near-cCR patients without compromising survival.

METHODS

Between May 2017 to September 2021, 80 patients with T3-4N0M0 or TanyN+M0 mid-low rectal cancer achieving cCR or near-cCR post-nCRT were prospectively included at 6 Chinese centers. Patients underwent either TEM (Group A, n = 38) or radical surgery (Group B, n = 41). Clinicopathological, oncological, and functional outcomes were analyzed.

RESULTS

Postoperative histology revealed 22 ypT0 (57.9 %), 5 ypT1 (13.2 %), 10 ypT2 (26.3 %), and 1 ypT3 (2.6 %) cases in group A and 20 pCR (48.8 %), 1 T0N1 (2.4 %), 5 T1N0 (12.2 %), 12 T2-3N0 (29.3 %), 3 T2-3N1 (7.3 %) cases in group B. After a 60-month median follow-up, local recurrence occurred in 2 patients (5.26 %) in Group A and none in Group B. Distant metastases occurred in 8 patients (21.05 %) in group A and 7 (17.07 %) in group B. There was no significant difference between the two groups in 5-year disease-free survival (P = 0.658) or 5-year overall survival (P = 0.465). Group A showed significantly faster recovery (P < 0.001) and better sphincter function per Wexner (1 vs. 4, P = 0.001) and LARS (0 vs. 17, P < 0.001) scores than Group B.

CONCLUSION

TEM may be an effective approach for assessing residual tumors in LARC patients with cCR or near-cCR. This approach offers an option for those requiring sphincter preservation, with no significant compromise in long-term oncological outcomes observed in our study.

Mastering rectal cancer MRI: From foundational concepts to optimal staging

MRI plays a critical role in the local staging, restaging, surveillance, and risk stratification of patients, ensuring they receive the most tailored therapy. As such, radiologists must be familiar not only with the key MRI findings that influence management decisions but also with the appropriate MRI protocols and structured reporting. Given the complexity of selecting the optimal therapy for each patient-which often requires multidisciplinary discussions-radiologists should be well-versed in relevant treatment strategies and surgical terms, understanding their significance in guiding patient care. In this manuscript, we review the most common treatment options for managing patients with rectal adenocarcinoma, emphasizing key MRI principles and protocol characteristics for accurate staging. We also highlight important anatomical landmarks and essential factors to be described during baseline assessment. Additionally, we discuss crucial information for restaging and surveillance.

Economic Evaluation of 'Watch and Wait' Following Neoadjuvant Therapy in Locally Advanced Rectal Cancer: A Systematic Review

BACKGROUND

Owing to multimodal treatment and complex surgery, locally advanced rectal cancer (LARC) exerts a large healthcare burden. Watch and wait (W&W) may be cost saving by removing the need for surgery and inpatient care. This systematic review seeks to identify the economic impact of W&W, compared with standard care, in patients achieving a complete clinical response (cCR) following neoadjuvant therapy for LARC.

METHODS

The PubMed, OVID Medline, OVID Embase, and Cochrane CENTRAL databases were systematically searched from inception to 26 April 2024. All economic evaluations (EEs) that compared W&W with standard care were included. Reporting and methodological quality was assessed using the Consolidated Health Economic Evaluation Reporting Standards (CHEERS), BMJ and Philips checklists. Narrative synthesis was performed. Primary and secondary outcomes were (incremental) cost-effectiveness ratios and the net financial cost.

RESULTS

Of 1548 studies identified, 27 were assessed for full-text eligibility and 12 studies from eight countries (2016-2024) were included. Seven cost-effectiveness analyses (complete EEs) and five cost analyses (partial EEs) utilized model-based (n = 7) or trial-based (n = 5) analytics with significant variations in methodological design and reporting quality. W&W showed consistent cost effectiveness (n = 7) and cost saving (n = 12) compared with surgery from third-party payer and patient perspectives. Critical parameters identified by uncertainty analysis were rates of local and distant recurrence in W&W, salvage surgery, perioperative mortality and utilities assigned to W&W and surgery.

CONCLUSION

Despite heterogenous methodological design and reporting quality, W&W is likely to be cost effective and cost saving compared with standard care following cCR in LARC. Clinical Trials Registration PROSPERO CRD42024513874.

Nonoperative management of rectal cancer

The management of locally advanced rectal cancer has changed drastically in the last few decades due to improved surgical techniques, development of multimodal treatment approaches and the introduction of a watch and wait (WW) strategy. For patients with a complete response to neoadjuvant treatment, WW offers an opportunity to avoid the morbidity associated with total mesorectal excision in favor of organ preservation. Despite growing interest in WW, prospective data on the safety and efficacy of nonoperative management are limited. Challenges remain in optimizing multimodal treatment regimens to maximize tumor regression and in improving the accuracy of patient selection for WW. This review summarizes the history of treatment for rectal cancer and the development of a WW strategy. It also provides an overview of clinical considerations for patients interested in nonoperative management, including restaging strategies, WW selection criteria, surveillance protocols and long-term oncologic outcomes.

Neoadjuvant therapy in rectal cancer-one year follow-up results of standard versus total neoadjuvant strategies

BACKGROUND

Locally advanced rectal cancer (LARC) poses a significantly challenge in clinical management, requiring a multimodal treatment approach. Among innovative strategies, Total Neoadjuvant Therapy (TNT) has emerged, delivering all planned chemotherapy before surgery.

OBJECTIVE

Our aim was to evaluate the real-world application and efficacy of TNT and to compare it with the non-TNT standard strategy.

METHODS

This retrospective study compared locally advanced rectal adenocarcinoma patients treated with Total Neoadjuvant Therapy (TNT) in 2022 with those who underwent traditional chemoradiotherapy (CRT) in 2020-2021. The primary endpoints were the pathologic complete response rate and the sustained clinical complete response rate in patients under W&W.

RESULTS

Among 107 patients (54.2% male, mean age 62.48 years), non-TNT (67 patients) and TNT (40 patients) mean follow-ups were 26.7 and 8.2 months, respectively. No differences in gender(p = 0.163), staging (p = 0.707), or location (p = 0.727) were noted. TNT patients received more short-course radiotherapy (42.5% vs1.5%, p < 0.001). Clinical responses favored TNT (p = 0.030) with no significant differences in pathological responses, recurrence rates, or survival. TNT exhibited higher chemotherapy completion (p = 0.007) and lower adverse events (p < 0.001). Post-surgery events showed no significant differences (p = 0.470). Single center with retrospective design and carries limitations that may restrict the generalizability of the findings and the relatively short follow-up duration are our main limitations.

CONCLUSION

Our data add to the body of literature favoring the TNT treatment strategy for locally advanced rectal cancer, aiming to achieve comparable complete response rates with less adverse events.

Response prediction for neoadjuvant treatment in locally advanced rectal cancer patients-improvement in decision-making: A systematic review

BACKGROUND

Predicting pathological complete response (pCR) from pre or post-treatment features could be significant in improving the process of making clinical decisions and providing a more personalized treatment approach for better treatment outcomes. However, the lack of external validation of predictive models, missing in several published articles, is a major issue that can potentially limit the reliability and applicability of predictive models in clinical settings. Therefore, this systematic review described different externally validated methods of predicting response to neoadjuvant chemoradiotherapy (nCRT) in locally advanced rectal cancer (LARC) patients and how they could improve clinical decision-making.

METHOD

An extensive search for eligible articles was performed on PubMed, Cochrane, and Scopus between 2018 and 2023, using the keywords: (Response OR outcome) prediction AND (neoadjuvant OR chemoradiotherapy) treatment in 'locally advanced Rectal Cancer'.

INCLUSION CRITERIA

(i) Studies including patients diagnosed with LARC (T3/4 and N- or any T and N+) by pre-medical imaging and pathological examination or as stated by the author (ii) Standardized nCRT completed. (iii) Treatment with long or short course radiotherapy. (iv) Studies reporting on the prediction of response to nCRT with pathological complete response (pCR) as the primary outcome. (v) Studies reporting external validation results for response prediction. (vi) Regarding language restrictions, only articles in English were accepted.

EXCLUSION CRITERIA

(i) We excluded case report studies, conference abstracts, reviews, studies reporting patients with distant metastases at diagnosis. (ii) Studies reporting response prediction with only internally validated approaches.

DATA COLLECTION AND QUALITY ASSESSMENT

Three researchers (DC-D, FB, HT) independently reviewed and screened titles and abstracts of all articles retrieved after de-duplication. Possible disagreements were resolved through discussion among the three researchers. If necessary, three other researchers (LB, GC, MG) were consulted to make the final decision. The extraction of data was performed using the CHecklist for critical Appraisal and data extraction for systematic Reviews of prediction Modelling Studies (CHARMS) template and quality assessment was done using the Prediction model Risk Of Bias Assessment Tool (PROBAST).

RESULTS

A total of 4547 records were identified from the three databases. After excluding 392 duplicate results, 4155 records underwent title and abstract screening. Three thousand and eight hundred articles were excluded after title and abstract screening and 355 articles were retrieved. Out of the 355 retrieved articles, 51 studies were assessed for eligibility. Nineteen reports were then excluded due to lack of reports on external validation, while 4 were excluded due to lack of evaluation of pCR as the primary outcome. Only Twenty-eight articles were eligible and included in this systematic review. In terms of quality assessment, 89 % of the models had low concerns in the participants domain, while 11 % had an unclear rating. 96 % of the models were of low concern in both the predictors and outcome domains. The overall rating showed high applicability potential of the models with 82 % showing low concern, while 18 % were deemed unclear.

CONCLUSION

Most of the external validated techniques showed promising performances and the potential to be applied in clinical settings, which is a crucial step towards evidence-based medicine. However, more studies focused on the external validations of these models in larger cohorts is necessary to ensure that they can reliably predict outcomes in diverse populations.

Complement is increased in treatment resistant rectal cancer and modulates radioresistance

Resistance to neoadjuvant chemoradiation therapy (neo-CRT) is a significant clinical problem in the treatment of locally advanced rectal cancer. Identification of novel therapeutic targets and biomarkers predicting therapeutic response is required to improve patient outcomes. Increasing evidence supports a role for the complement system in resistance to anti-cancer therapy. In this study, increased expression of complement effectors C3 and C5 and increased production of anaphylatoxins, C3a and C5a, was observed in radioresistant rectal cancer cells. Modulation of the central complement effector, C3, was demonstrated to functionally alter the radioresponse, with C3 overexpression significantly enhancing radioresistance, whilst C3 inhibition significantly increased sensitivity to a clinically-relevant dose of radiation. Inhibition of C3 was demonstrated to increase DNA damage and alter cell cycle distribution, mediating a shift towards a radiosensitive cell cycle phenotype suggesting a role for C3 in reprogramming of the tumoural radioresponse. Expression of the complement effectors C3 and C5 was significantly increased in human rectal tumour tissue, as was expression of CFB, a component of the alternative pathway of activation. Elevated levels of C3a and C5b-9 in pre-treatment sera from rectal cancer patients was associated with subsequent poor responses to neo-CRT and poorer survival. Together these data demonstrate a role for complement in the radioresistance of rectal cancer and identify key complement components as potential biomarkers predicting response to neo-CRT and outcome in rectal cancer.

Organ preservation after neoadjuvant long-course chemoradiotherapy versus short-course radiotherapy

BACKGROUND

Potential differences in organ preservation between total neoadjuvant therapy (TNT) regimens integrating long-course chemoradiotherapy (LCCRT) and short-course radiotherapy (SCRT) in rectal cancer remain undefined.

PATIENTS AND METHODS

This natural experiment arose from a policy change in response to the COVID-19 pandemic during which our institution switched from uniformly treating patients with LCCRT to mandating that all patients be treated with SCRT. Our study includes 323 locally advanced rectal adenocarcinoma patients treated with LCCRT-based or SCRT-based TNT from January 2018 to January 2021. Patients who achieved clinical complete response were offered organ preservation with watch-and-wait (WW) management. The primary outcome was 2-year organ preservation. Additional outcomes included local regrowth, distant recurrence, disease-free survival (DFS), and overall survival (OS).

RESULTS

Patient and tumor characteristics were similar between LCCRT (n = 247) and SCRT (n = 76) cohorts. Median follow-up was 31 months. Similar clinical complete response rates were observed following LCCRT and SCRT (44.5% versus 43.4%). Two-year organ preservation was 40% [95% confidence interval (CI) 34% to 46%] and 31% (95% CI 22% to 44%) among all patients treated with LCCRT and SCRT, respectively. In patients managed with WW, LCCRT resulted in higher 2-year organ preservation (89% LCCRT, 95% CI 83% to 95% versus 70% SCRT, 95% CI 55% to 90%; P = 0.005) and lower 2-year local regrowth (19% LCCRT, 95% CI 11% to 26% versus 36% SCRT, 95% CI 16% to 52%; P = 0.072) compared with SCRT. The 2-year distant recurrence (10% versus 6%), DFS (90% versus 90%), and OS (99% versus 100%) were similar between WW patients treated with LCCRT and SCRT, respectively.

CONCLUSIONS

While WW eligibility was similar between cohorts, WW patients treated with LCCRT had higher 2-year organ preservation and lower local regrowth than those treated with SCRT, yet similar DFS and OS. These data support induction LCCRT followed by consolidation chemotherapy as the preferred TNT regimen for patients with locally advanced rectal cancer pursuing organ preservation.

Gut microbiome model predicts response to neoadjuvant immunotherapy plus chemoradiotherapy in rectal cancer

BACKGROUND

Accurate evaluation of the response to preoperative treatment enables the provision of a more appropriate personalized therapeutic schedule for locally advanced rectal cancer (LARC), which remains an enormous challenge, especially neoadjuvant immunotherapy plus chemoradiotherapy (nICRT).

METHODS

This prospective, multicenter cohort study enrolled patients with LARC from 6 centers who received nICRT. The dynamic variation in the gut microbiome during nICRT was evaluated. A species-level gut microbiome prediction (SPEED) model was developed and validated to predict the pathological complete response (pCR) to nICRT.

FINDINGS

A total of 50 patients were enrolled, 75 fecal samples were collected from 33 patients at different time points, and the pCR rate reached 42.4% (14/33). Lactobacillus and Eubacterium were observed to increase after nICRT. Additionally, significant differences in the gut microbiome were observed between responders and non-responders at baseline. Significantly higher abundances of Lachnospiraceae bacterium and Blautia wexlerae were found in responders, while Bacteroides, Prevotella, and Porphyromonas were found in non-responders. The SPEED model showcased a superior predictive performance with areas under the curve of 98.80% (95% confidence interval [CI]: 95.67%-100%) in the training cohort and 77.78% (95% CI: 65.42%-88.29%) in the validation cohort.

CONCLUSIONS

Programmed death 1 (PD-1) blockade plus concurrent long-course CRT showed a favorable pCR rate and is well tolerated in microsatellite-stable (MSS)/mismatch repair-proficient (pMMR) patients with LARC. The SPEED model can be used to predict the pCR to nICRT based on the baseline gut microbiome with high robustness and accuracy, thereby assisting clinical physicians in providing individualized management for patients with LARC.

FUNDING

This research was funded by the China National Natural Science Foundation (82202884).

Local excision versus total mesorectal excision for rectal cancer patients with clinical complete or near-complete response after neoadjuvant chemoradiotherapy

PURPOSE

Local excision is an effective approach for managing rectal cancer exhibiting substantial regression after neoadjuvant chemoradiotherapy. The purpose of this study is to compare the outcomes between local excision and total mesorectal excision in rectal cancer patients achieving clinical complete or near-complete response after neoadjuvant chemoradiotherapy.

METHODS

This is a retrospective cohort study that includes a consecutive series of rectal cancer patients who responded well to neoadjuvant chemoradiotherapy followed by surgery. A total of 180 rectal cancer patients at a single institution during a 12-year period are included. The main outcomes include short-term outcomes, oncological outcomes, and functional outcomes between the two groups.

RESULTS

A total of 180 patients were included in the study. Sixty-one (33.9%) received local excision and 119 (66.1%) received total mesorectal excision. The baseline characteristics were generally balanced between the two groups. The local excision group demonstrated a significantly shorter operative time, less blood loss, and shorter hospital stay (p < 0.001). 3-year overall survival rates were 97.5% (95% CI, 0.93-1.00) and 95.5% (95% CI, 0.91-1.00) between the two groups (p = 0.38). The local excision group exhibited significantly higher 3-year local recurrence rates 15.7% (95% CI, 0.74-0.97) vs 4.2% (95% CI, 0.92-1.00) (p = 0.017), yet lower 3-year distant metastasis rates 9.6% (95% CI, 0.82-1.00) vs 12.6% (95% CI, 0.81-0.94) (p = 0.33) and lower 3-year disease-free survival rates 76.8% (95% CI, 0.64-0.92) vs 84.7% (95% CI, 0.78-0.92) (p = 0.56) comparing with the total mesorectal excision group. The local excision group demonstrated significantly better functional outcomes compared with the total mesorectal excision group (p < 0.001).

CONCLUSION

Patients who achieve either clinical complete or near-complete response after neoadjuvant chemoradiotherapy are suitable candidates for local excision. The local excision group demonstrated superior short-term and functional outcomes, and the oncological outcomes were not compromised.

Neoadjuvant Treatment in Rectal Cancer

A major advance in rectal cancer was the evidence supporting short-course radiotherapy and long-course chemoradiotherapy. Both have been shown to improve local outcomes. Total neoadjuvant therapy (TNT) is the new kid on the block that provides further benefit of improving local responses as well as reducing systemic relapses, thus increasing overall survival. Details of the four key TNT trials are discussed. They pave the way for nonoperative management for patients who achieve clinical complete responses.

Neoadjuvant short-course radiotherapy followed by camrelizumab and chemotherapy in locally advanced rectal cancer (UNION): early outcomes of a multicenter randomized phase III trial

BACKGROUND

Neoadjuvant short-course radiotherapy (SCRT) followed by CAPOX and camrelizumab (a programmed cell death protein 1 monoclonal antibody) has shown potential clinical activity for locally advanced rectal cancer (LARC) in a phase II trial. This study aimed to further confirm the efficacy and safety of SCRT followed by CAPOX and camrelizumab compared to long-course chemoradiotherapy (LCRT) followed by CAPOX alone as neoadjuvant treatment for LARC.

PATIENTS AND METHODS

In this randomized, phase III trial, patients with T3-4/N+ rectal adenocarcinoma were randomly assigned (1 : 1) to receive SCRT or long-course chemoradiotherapy (LCRT), followed by two cycles of camrelizumab and CAPOX or CAPOX alone, respectively. After surgery, each arm underwent either six cycles of camrelizumab and CAPOX, followed by up to 17 doses of camrelizumab, or six cycles of CAPOX. The primary endpoint was pathological complete response (pCR) rate (ypT0N0) assessed by a blinded independent review committee. Key secondary endpoints tested hierarchically were 3-year event-free survival (EFS) rate and overall survival (OS).

RESULTS

Between July 2021 and March 2023, the intention-to-treat population comprised 113 patients in the experimental arm and 118 patients in the control arm, with surgery carried out in 92% and 83.9%, respectively. At data cut-off (11 July 2023), the pCR rates were 39.8% [95% confidence interval (CI) 30.7% to 49.5%] in the experimental arm compared to 15.3% (95% CI 9.3% to 23.0%) in the control arm (difference, 24.6%; odds ratio, 3.7; 95% CI 2.0-6.9; P < 0.001). In each arm, surgical complication rates were 40.0% and 40.8%, and grade ≥3 treatment-related adverse events were 29.2% and 27.2%. Three-year EFS rate and OS continue to mature.

CONCLUSIONS

In LARC patients, neoadjuvant SCRT followed by camrelizumab plus CAPOX demonstrated a significantly higher pCR rate than LCRT followed by CAPOX, with a well-tolerated safety profile. SCRT followed by camrelizumab and chemotherapy can be recommended as a neoadjuvant treatment modality for these patients.

Efficacy and safety of MR-guided adaptive simultaneous integrated boost radiotherapy to primary lesions and positive lymph nodes in the neoadjuvant treatment of locally advanced rectal cancer: a randomized controlled phase III trial

BACKGROUND

In locally advanced rectal cancer (LARC), optimizing neoadjuvant strategies, including the addition of concurrent chemotherapy and dose escalation of radiotherapy, is essential to improve tumor regression and subsequent implementation of anal preservation strategies. Currently, dose escalation studies in rectal cancer have focused on the primary lesions. However, a common source of recurrence in LARC is the metastasis of cancer cells to the proximal lymph nodes. In our trial, we implement simultaneous integrated boost (SIB) to both primary lesions and positive lymph nodes in the experimental group based on magnetic resonance-guided adaptive radiotherapy (MRgART), which allows for more precise (and consequently intense) targeting while sparing neighboring healthy tissue. The objective of this study is to evaluate the efficacy and safety of MRgART dose escalation to both primary lesions and positive lymph nodes, in comparison with the conventional radiotherapy of long-course concurrent chemoradiotherapy (LCCRT) group, in the neoadjuvant treatment of LARC.

METHODS

This is a multi-center, randomized, controlled phase III trial (NCT06246344). 128 patients with LARC (cT3-4/N+) will be enrolled. During LCCRT, patients will be randomized to receive either MRgART with SIB (60-65 Gy in 25-28 fractions to primary lesions and positive lymph nodes; 50-50.4 Gy in 25-28 fractions to the pelvis) or intensity-modulated radiotherapy (50-50.4 Gy in 25-28 fractions). Both groups will receive concurrent chemotherapy with capecitabine and consolidation chemotherapy of either two cycles of CAPEOX or three cycles of FOLFOX between radiotherapy and surgery. The primary endpoints are pathological complete response (pCR) rate and surgical difficulty, while the secondary endpoints are clinical complete response (cCR) rate, 3-year and 5-year disease-free survival (DFS) and overall survival (OS) rates, acute and late toxicity and quality of life.

DISCUSSION

Since dose escalation of both primary lesions and positive nodes in LARC is rare, we propose conducting a phase III trial to evaluate the efficacy and safety of SIB for both primary lesions and positive nodes in LARC based on MRgART.

TRIAL REGISTRATION

The study was registered at ClinicalTrials.gov with the Identifier: NCT06246344 (Registered 7th Feb 2024).

Journey through the Decades: The Evolution in Treatment and Shared Decision Making for Locally Advanced Rectal Cancer

The management of locally advanced rectal cancer has undergone significant transformations over the decades and optimal treatment approaches continue to evolve. There have been numerous advances in surgery, chemotherapy, and radiation therapy from the first description of the abdominoperineal resection in 1908, timing of chemotherapy and radiation therapy in the late 20th and early 21st century, and most recently, the introduction of organ preservation or nonoperative management in 2004. Alongside these advancements, the concept of shared decision making in medicine has evolved, prompting a focus on patient-centered care. This evolution in practice has been fueled by a growing recognition of the importance of patient autonomy and the alignment of treatment options with patients' values and preferences. With the growing number of possible treatment options, variability in patient counseling exists, highlighting the need for a standardized approach to shared decision making in locally advanced rectal cancer. This narrative review will describe the evolution of treatment options of locally advanced rectal cancer as well as the concept of shared decision making and decision aids, and will introduce a decision aid for patients with locally advanced rectal cancer who have achieved a complete clinical response and are eligible for watch and wait.

Impact of the interval between neoadjuvant immunotherapy and surgery on prognosis in esophageal squamous cell carcinoma (ESCC): a real-world study

BACKGROUND

The time interval between neoadjuvant immunotherapy and surgery is 6 weeks for esophageal squamous cell carcinoma (ESCC), but whether delayed surgery affects prognosis remains unclear.

METHODS

Clinical data of locally advanced ESCC who underwent neoadjuvant immunotherapy followed by esophagectomy from November 2019 to December 2022 were collected. The surgery outcomes and prognosis were compared between short-interval (time to surgery ≤ 6 weeks) and long-interval groups (time to surgery > 6 weeks).

RESULTS

152 patients were enrolled totally, with a ratio of 91:61 between short-interval and long-interval groups. The rate of pathological complete response in the short-interval and long-interval groups were 34.1% and 24.6% (P = 0.257). Delayed surgery did not have a significantly impact on the number of lymph node dissections (P = 0.133), operative duration (P = 0.689), blood loss (P = 0.837), hospitalization duration (P = 0.293), chest drainage duration (P = 0.886) and postoperative complications (P > 0.050). The 3-year Overall survival (OS) rates were 85.10% in the short-interval group, and 82.07% in the long-interval group (P = 0.435). The 3-year disease-free survival (DFS) rates were 83.41% and 70.86% in the two groups (P = 0.037). Subgroup analysis revealed that patients with a favorable response to immunotherapy (tumor regression grade 0) exhibited inferior 3-year OS (long-interval vs. short-interval: 51.85% vs. 91.08%, P = 0.035) and DFS (long-interval vs. short-interval: 47.40% vs. 91.08%, P = 0.014) in the long-interval group.

CONCLUSIONS

Delayed surgery after neoadjuvant immunotherapy does not further improve pathological response; instead, it resulted in a poorer DFS. Especially for patients with a favorable response to immunotherapy, delayed surgery increases the risk of mortality and recurrence.

Nonoperative management and local excision after neoadjuvant chemoradiation therapy for rectal cancer

Locally advanced extraperitoneal rectal cancer represents a significant clinical challenge, and currently, the standard treatment is based on neoadjuvant chemoradiation therapy (CRT) followed by radical surgical resection with total mesorectal excision (TME). In the last 30 years, its management has undergone significant changes due to the improvement of complementary radio- and chemotherapy treatments, the improvement of minimally invasive surgical approaches and the diffusion of organ-sparing approaches, such as nonoperative management, commonly called "watch and wait" (NOM) and local excision (LE), in highly selected patients who achieve a major or complete response to neoadjuvant CRT. This review aimed to critically examine the efficacy and oncological safety of NOM and LE compared to those of standard TME in rectal cancer patients after neoadjuvant CRT. Both the pros and cons of these approaches were strictly analyzed, providing a comprehensive and critical overview of these novel management strategies for rectal cancer.

MOREOVER: multiomics MR-guided radiotherapy optimization in locally advanced rectal cancer

BACKGROUND

Complete response prediction in locally advanced rectal cancer (LARC) patients is generally focused on the radiomics analysis of staging MRI. Until now, omics information extracted from gut microbiota and circulating tumor DNA (ctDNA) have not been integrated in composite biomarkers-based models, thereby omitting valuable information from the decision-making process. In this study, we aim to integrate radiomics with gut microbiota and ctDNA-based genomics tracking during neoadjuvant chemoradiotherapy (nCRT).

METHODS

The main hypothesis of the MOREOVER study is that the incorporation of composite biomarkers with radiomics-based models used in the THUNDER-2 trial will improve the pathological complete response (pCR) predictive power of such models, paving the way for more accurate and comprehensive personalized treatment approaches. This is due to the inclusion of actionable omics variables that may disclose previously unknown correlations with radiomics. Aims of this study are: - to generate longitudinal microbiome data linked to disease resistance to nCRT and postulate future therapeutic strategies in terms of both type of treatment and timing, such as fecal microbiota transplant in non-responding patients. - to describe the genomics pattern and ctDNA data evolution throughout the nCRT treatment in order to support the prediction outcome and identify new risk-category stratification agents. - to mine and combine collected data through integrated multi-omics approaches (radiomics, metagenomics, metabolomics, metatranscriptomics, human genomics, ctDNA) in order to increase the performance of the radiomics-based response predictive model for LARC patients undergoing nCRT on MR-Linac.

EXPERIMENTAL DESIGN

The objective of the MOREOVER project is to enrich the phase II THUNDER-2 trial (NCT04815694) with gut microbiota and ctDNA omics information, by exploring the possibility to enhance predictive performance of the developed model. Longitudinal ctDNA genomics, microbiome and genomics data will be analyzed on 7 timepoints: prior to nCRT, during nCRT on a weekly basis and prior to surgery. Specific modelling will be performed for data harvested, according to the TRIPOD statements.

DISCUSSION

We expect to find differences in fecal microbiome, ctDNA and radiomics profiles between the two groups of patients (pCR and not pCR). In addition, we expect to find a variability in the stability of the considered omics features over time. The identified profiles will be inserted into dedicated modelling solutions to set up a multiomics decision support system able to achieve personalized treatments.

Neoadjuvant treatment of rectal cancer: Where we are and where we are going

Locally advanced rectal cancer requires a multidisciplinary approach based on total neoadjuvant treatment with radiotherapy (RT) and chemotherapy (ChT), followed by deferred surgery. Currently, alternatives to the standard total neoadjuvant therapy (TNT) are being explored, such as new ChT regimens or the introduction of immunotherapy. With standard TNT, up to a third of patients may achieve a complete pathological response (CPR), potentially avoiding surgery. However, as of now, we lack predictive markers of response that would allow us to define criteria for a conservative organ strategy. The presence of mutations, genes, or new imaging tests is helping to define these criteria. An example of this is the diffusion coefficient in the diffusion-weighted sequence of magnetic resonance imaging and the integration of this imaging technique into RT treatment. This allows for the monitoring of the evolution of this coefficient over successive RT sessions, helping to determine which patients will achieve CPR or those who may require intensification of neoadjuvant therapy.

[Transanal Endoscopic Microsurgery (TEM) is a surgical option to preserve fecal continence in selected low rectal cancers]

INTRODUCTION

Despite its existence for more than 40 years, the TEM method has not become widespread. The main reasons are the high acquisition costs, the sophisticated technology and alternative procedures (especially radical resection procedures), which provide greater oncological safety. However, avoiding major abdominal surgery with the creation of a stoma and higher complication rates can outweigh the higher risk of recurrence for some patients. We examined the results using V-TEM with reduced acquisition costs in the resection of adenomas and carcinomas and discussed its importance by literature .

METHOD

From 2003 to 2019, 154 patients with 170 findings were operated by V-TEM technology. Data on the operation and follow-up were collected and analyzed retrospectively.

RESULTS

The median age was 67 years, 89 patients were male and 65 female. V-TEM was performed on 79 carcinomas, 77 adenomas and 14 other findings. The complication rate was 21.2 %. R0 resection was achieved in 78.8 %. The adenoma recurrence rate was 7.3 %, the overall recurrence rate for carcinomas 11.9 %, local recurrences were observed in 6.8 %. The disease-specific survival is 100 % at 5 years and 94.2 % at ten years.

DISCUSSION

The successful use of TEM in adenomas and early carcinomas is undisputed. When treating carcinomas from a T1 high risk stage using TEM, recurrence rates higher than 10 % must be expected. Better results can be achieved with radical procedures, this is why they are considered the therapy of choice in these cases. However, there are no differences in terms of survival rates and TEM offers proven better postoperative quality of life. In particular, the combination of neoadjuvant procedures with TEM delivered promising results in more advanced stages. Further studies on TEM and the possibility of lower acquisition costs through modification to V-TEM could make the method more popular in the future.

Shared Decision-Making, Sphincter Preservation, and Rectal Cancer Treatment: Identifying and Executing What Matters Most to Patients

Rectal cancer treatment often encompasses multiple steps and options, with benefits and risks that vary based on the individual. Additionally, patients facing rectal cancer often have preferences regarding overall quality of life, which includes bowel function, sphincter preservation, and ostomies. This article reviews these data in the context of shared decision-making approaches in an effort to better inform patients deliberating treatment options for rectal cancer.

Rectal Cancer Survival for Residual Carcinoma In Situ Versus Pathologic Complete Response After Neoadjuvant Therapy

BACKGROUND

Pathologic complete response after neoadjuvant chemoradiotherapy for rectal cancer is associated with improved survival. It is unclear whether residual carcinoma in situ portends a similar outcome.

OBJECTIVE

To compare the survival of patients with locally advanced rectal cancer who received neoadjuvant therapy and achieved pathologic carcinoma in situ versus pathologic complete response.

DESIGN

Retrospective cohort study.

SETTING

National public database.

PATIENTS

A total of 4594 patients in the National Cancer Database from 2006 to 2016 with locally advanced rectal cancer who received neoadjuvant therapy, underwent surgery, and had node-negative ypTis or ypT0 on final pathology were included. Of these, 4321 patients (94.1%) had ypT0 and 273 (5.9%) had ypTis on final pathology.

MAIN OUTCOME MEASURE

Overall survival.

RESULTS

The median age was 60 years, and 1822 patients (39.7%) were women. On initial staging, 54.5% (n = 2503) had stage II disease and 45.5% (n = 2091) had stage III disease. The ypTis group had decreased overall survival compared to the ypT0 group (HR 1.42; 95% CI, 1.04-1.95; p  = 0.028). Other factors associated with decreased overall survival were older age at diagnosis, increasing Charlson-Deyo score, and poorly differentiated tumor grade. Variables associated with improved survival were female sex, private insurance, and receipt of both neoadjuvant and adjuvant chemotherapy. For the total cohort, there was no difference in survival between clinical stage II and stage III.

LIMITATIONS

Standard therapy versus total neoadjuvant therapy could not be abstracted. Overall survival was defined as the time from surgery to death from any cause or last contact, allowing for some erroneously misclassified deaths.

CONCLUSIONS

ypTis is associated with worse overall survival than ypT0 for patients with locally advanced rectal cancer who receive neoadjuvant chemoradiotherapy followed by surgery. For this cohort, clinical stage was not a significant predictor of survival. Prospective trials comparing survival for these pathologic outcomes are needed. See Video Abstract .

SUPERVIVENCIA DEL CNCER DE RECTO PARA EL CARCINOMA RESIDUAL IN SITU VS RESPUESTA PATOLGICA COMPLETA DESPUS DE LA TERAPIA NEOADYUVANTE

ANTECEDENTESLa respuesta patológica completa después de la quimiorradioterapia neoadyuvante para el cáncer de recto se asocia con una mayor supervivencia. No está claro si el carcinoma residual in situ presagia un resultado similar.OBJETIVOComparar la supervivencia de pacientes con cáncer de recto localmente avanzado que recibieron terapia neoadyuvante y lograron un carcinoma patológico in situ versus una respuesta patológica completa.DISEÑOEstudio de cohorte retrospectivo.ESCENARIOBase de datos pública nacional.PACIENTESSe incluyeron 4,594 pacientes de la Base de Datos Nacional de Cáncer de 2006 a 2016 con cáncer de recto localmente avanzado que recibieron terapia neoadyuvante, fueron sometidos a cirugía y tuvieron ganglios negativos, ypTis o ypT0 en el reporte patológico final. 4.321 (94,1%) tuvieron ypT0 y 273 (5,9%) tuvieron ypTis en el reporte final.PRINCIPALES MEDIDAS DE RESULTADOSupervivencia general.RESULTADOSLa mediana de edad fue de 60 años. 1.822 pacientes (39,7%) fueron mujeres. El 54,5% (n = 2.503) tuvo la enfermedad en estadio II y el 45,5% (n = 2.091) tuvo la enfermedad en estadio III según la estadificación inicial. El grupo ypTis tuvo una supervivencia general reducida en comparación con el grupo ypT0 (HR 1,42, IC 95 % 1,04-1,95, p = 0,028). Otros factores asociados con una menor supervivencia general fueron una edad más avanzada al momento del diagnóstico, un aumento de la puntuación de Charlson-Deyo y un grado tumoral poco diferenciado. Las variables asociadas con una mejor supervivencia fueron el sexo femenino, el seguro privado y la recepción de quimioterapia neoadyuvante y adyuvante. Para la cohorte total, no hubo diferencias en la supervivencia entre el estadio clínico 2 y el estadio 3.LIMITACIONESNo se pudo resumir el tratamiento estándar versus el tratamiento neoadyuvante total. La supervivencia general se definió como el tiempo transcurrido desde la cirugía hasta la muerte por cualquier causa o último contacto, lo que permite algunas muertes erróneamente clasificadas.CONCLUSIONESypTis se asocia con una peor supervivencia general que ypT0 en pacientes con cáncer de recto localmente avanzado que reciben quimiorradioterapia neoadyuvante seguida de cirugía. Para esta cohorte, el estadio clínico no fue un predictor significativo de supervivencia. Se necesitan ensayos prospectivos que comparen la supervivencia de estos resultados patológicos. ( Traducción-Dr Osvaldo Gauto ).

High Rates of Organ Preservation in Rectal Cancer with Papillon Contact X-ray Radiotherapy: Results from a Swiss Cohort

Rectal cancer typically necessitates a combination of radiotherapy (RT), chemotherapy, and surgery. The associated functional disorders and reduction in quality of life have led to an increasing interest in organ preservation strategies. Response strongly correlates with RT dose, but dose escalation with external beam remains limited even with modern external beam RT techniques because of toxicity of the surrounding tissues. This study reports on the use of Papillon, an endocavitary Radiotherapy device, in the treatment of rectal cancer. The device delivers low energy X-rays, allowing for safe dose escalation and better complete response rate. Between January 2015 and February 2024, 24 rectal cancer patients were treated with the addition of a boost delivered by Papillon to standard RT, with or without chemotherapy, in an upfront organ preservation strategy. After a median follow-up (FU) of 43 months, the organ preservation rate was 96% (23/24), and the local relapse rate was 8% (2/24). None of our patients developed grade 3 or more toxicities. Our results demonstrate that the addition of Papillon contact RT provides a high rate of local remission with sustained long-term organ preservation, offering a promising alternative to traditional surgical approaches in patients with rectal cancer.

Significance of Nutritional-Inflammatory Index as Predictors for Total Neoadjuvant Therapy-Induced Tumor Regression in Locally Advanced Rectal Cancer Patients

Purpose

To evaluate the predictive capacity of the nutritional-inflammatory index and clinicopathological characteristics in patients with locally advanced rectal cancer (LARC) receiving total neoadjuvant therapy (TNT).

Methods

Data from 127 patients with LARC receiving TNT from January 2017 to January 2021 were retrospectively analyzed. Clinicopathological characteristics with different TNT-induced responses were compared. The Chi-square test and the Mann-Whitney test were used to analyze the association between pre-TNT factors and TNT-induced responses. Multivariable logistic regression analysis was used to construct a predictive model.

Results

In the cohort of 127 patients with LARC who underwent total neoadjuvant therapy (TNT), the mean age was 54.1 ± 11.4 years; 88 (69.3%) were male. Seventy patients (55.1%) exhibited a favorable response to TNT, while 57 patients (44.9%) demonstrated a poor response. Tumor characteristics, including diameter, distance from the anal verge, pre-TNT lymphocyte, pre-TNT hemoglobin, CA199, PLR, and HALP, exhibit correlations with TNT-induced tumor regression. Multivariate logistic regression analysis identified large tumor diameters (> 5.0 cm; p = 0.005, HR 2.958; 95% CI 1.382-6.335) and low HALP (≤ 40; p = 0.002, HR 0.261; 95% CI 0.111-0.612) as predictors of TNT-induced poor responses. Additionally, low levels of HALP were associated with an increased risk of recurrence in patients with LARC with TNT, but this was not statistically significant (p = 0.087, HR 2.008, 95% CI 0.906-4.447).

Conclusion

A large tumor diameter and low HALP predict poor tumor regression induced by the CAPOX-based TNT regimen in patients with LARC.

Outcome of Patients with Locally Advanced Rectal Cancer Pursuing Non-Surgical Strategy in National Cancer Database

BACKGROUND

Survival data on patients with locally advanced rectal cancer (LARC) undergoing non-operative management (NOM) in a real-world setting are lacking.

METHODS

We analyzed LARC patients from the National Cancer Database with the following features: treated between 2010 and 2020, age 18-65 years, Charlson comorbidity index (CCI) ≤ 1, received neoadjuvant multiagent chemotherapy plus radiation ≥ 45 Gray, and underwent surgery or NOM. Patients were stratified into two groups: (A) clinical T1-3 tumors with positive nodes (cT1-3N+) and (B) clinical T4 tumors, N+/- (cT4N+/-). We performed a comparative analysis of overall survival (OS) with NOM versus surgery by the Kaplan-Meier method and propensity score matching. Additionally, a multivariable analysis explored the association between NOM and OS.

RESULTS

NOM exhibited significantly lower OS than surgery in both groups. In cT1-3N+ patients, NOM resulted in a 5-year OS of 73.9% (95% confidence interval [CI] = 69.7-77.6%) versus 84.5% (95% CI = 83.6-85.3%) with surgery (p < 0.001). In the cT4N+/- group, NOM yielded a 5-year OS of 44.5% (95% CI = 37.0-51.8%) versus 72.5% (95% CI = 69.9-74.8%) with surgery (p < 0.001). Propensity score matching and multivariable analyses revealed similar conclusions.

CONCLUSION

Patients with LARC undergoing NOM versus surgery in real-world settings appear to have inferior survival.

Nonoperative management protocol for locally advanced rectal cancer

AIM

The standard treatment for low rectal cancer is preoperative chemoradiotherapy followed by surgery with low anterior resection with diverting ileostomy or abdominoperineal resection, both of which have significant long-term effects on bowel and sexual function. Due to the high morbidity of surgery, there has been increasing interest in nonoperative management for low rectal cancer. The aim of this work is to conduct a pan-Canadian Phase II trial assessing the safety of nonoperative management for low rectal cancer.

METHOD

Patients with Stage II or III low rectal cancer completing chemoradiotherapy according to standard of care at participating centres will be assessed for complete clinical response 8-14 weeks following completion of chemoradiotherapy. Subjects achieving a clinical complete response will undergo active surveillance including endoscopy, imaging and bloodwork at regular intervals for 24 months. The primary outcome will be the rate of local regrowth 2 years after chemoradiotherapy. Nonoperative management will be considered safe (i.e. as effective as surgery to achieve local control) if the rate of local regrowth is ≤30% and surgical salvage is possible for all local regrowths. Secondary outcomes will include disease-free and overall survival.

CONCLUSION

The results will be highly clinically relevant, as it is expected that nonoperative management will be safe and lead to widespread adoption of nonoperative management in Canada. This change in practice has the potential to decrease the number of patients requiring surgery and the costs associated with surgery and long-term surgical morbidity.

An International Expert-Based Consensus on the Definition of a Clinical Near-Complete Response After Neoadjuvant (Chemo)radiotherapy for Rectal Cancer

BACKGROUND

A variety of definitions for a clinical near-complete response after neoadjuvant (chemo) radiotherapy for rectal cancer are currently used. This variety leads to inconsistency in clinical practice, long-term outcome, and trial enrollment.

OBJECTIVE

The aim of this study was to reach expert-based consensus on the definition of a clinical near-complete response after (chemo) radiotherapy.

DESIGN

A modified Delphi process, including a systematic review, 3 surveys, and 2 meetings, was performed with an international expert panel consisting of 7 surgeons and 4 radiologists. The surveys consisted of individual features, statements, and feature combinations (endoscopy, T2-weighted MRI, and diffusion-weighted MRI).

SETTING

The modified Delphi process was performed in an online setting; all 3 surveys were completed online by the expert panel, and both meetings were hosted online.

MAIN OUTCOME MEASURES

The main outcome was to reach consensus (80% or more agreement).

RESULTS

The expert panel reached consensus on a 3-tier categorization of the near-complete response category based on the likelihood of the response to evolve into a clinical complete response after a longer waiting interval. The panelists agreed that a near-complete response is a temporary entity only to be used in the first 6 months after (chemo)radiotherapy. Furthermore, consensus was reached that the lymph node status should be considered when deciding on a near-complete response and that biopsies are not always needed when a near-complete response is found. No consensus was reached on whether primary staging characteristics have to be taken into account when deciding on a near-complete response.

LIMITATIONS

This 3-tier subcategorization is expert-based; therefore, there is no supporting evidence for this subcategorization. Also, it is unclear whether this subcategorization can be generalized into clinical practice.

CONCLUSIONS

Consensus was reached on the use of a 3-tier categorization of a near-complete response, which can be helpful in daily practice as guidance for treatment and to inform patients with a near-complete response on the likelihood of successful organ preservation. See Video Abstract.

UN CONSENSO INTERNACIONAL BASADO EN EXPERTOS ACERCA DE LA DEFINICIN DE UNA RESPUESTA CLNICA CASI COMPLETA DESPUS DE QUIMIORADIOTERAPIA NEOADYUVANTE CONTRA EL CNCER DE RECTO

ANTECEDENTES:Actualmente, se utilizan una variedad de definiciones para una respuesta clínica casi completa después de quimioradioterapia neoadyuvante contra el cáncer de recto. Esta variedad resulta en inconsistencia en la práctica clínica, los resultados a largo plazo y la inscripción en ensayos.OBJETIVO:El objetivo de este estudio fue llegar a un consenso de expertos sobre la definición de una respuesta clínica casi completa después de quimioradioterapia.DISEÑO:Se realizó un proceso Delphi modificado que incluyó una revisión sistemática, 3 encuestas y 2 reuniones con un panel internacional de expertos compuesto por siete cirujanos y 4 radiólogos. Las encuestas consistieron en características individuales, declaraciones y combinaciones de características (endoscopía, T2W-MRI y DWI).AJUSTE:El proceso Delphi modificado se realizó en un entorno en línea; el panel de expertos completó las tres encuestas en línea y ambas reuniones se realizaron en línea.PRINCIPALES MEDIDAS DE RESULTADO:El resultado principal fue llegar a un consenso (≥80% de acuerdo).RESULTADOS:El panel de expertos llegó a un consenso sobre una categorización de tres niveles de la categoría de respuesta casi completa basada en la probabilidad de que la respuesta evolucione hacia una respuesta clínica completa después de un intervalo de espera más largo. Los panelistas coincidieron en que una respuesta casi completa es una entidad temporal que sólo debe utilizarse en los primeros 6 meses después de la quimioradioterapia. Además, se llegó a un consenso en que se debe considerar el estado de los nódulos linfáticos al decidir sobre una respuesta casi completa y que no siempre se necesitan biopsias cuando se encuentra una respuesta casi completa. No se llegó a un consenso sobre si se deben tener en cuenta las características primarias de estadificación al decidir una respuesta casi completa.LIMITACIONES:Esta subcategorización de 3 niveles está basada en expertos; por lo tanto, no hay evidencia que respalde esta subcategorización. Además, no está claro si esta subcategorización puede generalizarse a la práctica clínica.CONCLUSIONES:Se alcanzó consenso sobre el uso de una categorización de 3 niveles de una respuesta casi completa que puede ser útil en la práctica diaria como guía para el tratamiento y para informar a los pacientes con una respuesta casi completa sobre la probabilidad de una preservación exitosa del órgano. (Traducción - Dr. Aurian Garcia Gonzalez).

MRI-based parameters and clinical risk factors to predict lymph node metastasis in patients with ypT0 rectal cancer after neoadjuvant chemoradiotherapy

BACKGROUNDS

The aim of this study was to assess the significant risk factors that predict lymph node metastasis in ypT0 patients with locally advanced rectal cancer following chemoradiotherapy (CRT). Additionally, the study aimed to identify high-risk groups who would not be suitable candidates for a rectal-preserving strategy, despite achieving a complete tumour response.

METHODS

Between 2013 and 2021, 226 ypT0 patients with stages II/III rectal cancer underwent CRT and radical surgery were enrolled. Two groups of patients were evaluated: those with lymph nodes metastasis and those without. The selection of variables for multivariable logistic regression was conducted through bivariate logistic regression analysis. Furthermore, the determination of optimal cutoff values for risk factors was achieved using ROC curve analysis.

RESULTS

Nearly 8% (18/226) of patients with ypT0 had positive lymph nodes (LN) on final pathology. Four variables resulted as being independent factors of LN metastasis: pre-CRT tumour movability (OR = 8.618, P = 0.003), pre-CRT maximal LN size (OR = 28.474, P = 0.004), post-CRT tumour vertical length (OR = 1.492, P = 0.050), post-CRT anaemia (OR = 10.288, P = 0.001). The optimal cutoff point of pre-CRT maximal LN size and post-CRT tumour vertical length was 7.50 mm and 3.05 cm, respectively.

CONCLUSION

The prevalence of lymph node metastasis remains at 8% among patients who achieve pathological complete regression of the primary tumour. In instances where patients are considered appropriate candidates for a rectal-preserving strategy after clinical complete remission, careful consideration should be given to the selection of this strategy if specific risk factors are present. These risk factors encompass a maximal LN size surpassing 7.50 mm prior to CRT, a fixed tumour prior to CRT, a tumour vertical length exceeding 3.05 cm after CRT, and the existence of anaemia subsequent to CRT.

Prolonged interval to surgery following neoadjuvant chemoradiotherapy in locally advanced rectal cancer: A meta-analysis of randomized controlled trials

BACKGROUND

Long-course neoadjuvant chemoradiotherapy (NCRT), followed by surgery after an interval of 6-8 weeks, represents standard of care for patients with locally advanced rectal cancer (LARC). Increasing this interval may improve rates of complete pathological response (pCR) and tumour downstaging. We performed a meta-analysis comparing standard (SI, within 8 weeks) versus longer (LI, after 8 weeks) interval from NCRT to surgery.

METHODS

PubMed, Embase, and Cochrane databases were searched up to 31 August 2022. Randomized controlled trials (RCTs) comparing SI with LI after NCRT for LARC were included. The primary endpoint was pCR rate. Secondary endpoints included rates of R0 resection, circumferential resection margin positivity (+CRM), TME completeness, lymph node yield (LNY), operative duration, tumour downstaging (TD), sphincter preservation, mortality, postoperative complications, surgical site infection (SSI) and anastomotic leak (AL). Random effects models were used to calculate pooled effect size estimates.

RESULTS

Four RCTs encompassing 867 patients were included. There were 539 males (62.1%). LI was associated with a higher pCR rate (OR 0.61, 95%CI ​= ​0.39-0.95, p ​= ​0.03), and more TD (OR 0.60, 95%CI ​= ​0.37-0.97, p ​= ​0.04) compared to SI. However, there was no difference in rates of R0 resection (p ​= ​0.87), +CRM (p ​= ​0.66), sphincter preservation (p ​= ​0.26), incomplete TME (p ​= ​0.49), LNY (p ​= ​0.55), SSI (p ​= ​0.33), AL (p ​= ​0.20), operative duration (p ​= ​0.07), mortality (p ​= ​0.89) or any surgical complication (p ​= ​0.91).

CONCLUSIONS

A LI to surgery after NCRT for LARC increases pCR and TD rates. Local recurrence or survival were not assessed due to unavailable data. We recommend deferring TME until after an interval of 8 weeks following completion of NCRT.

Watch-and-wait strategy vs. resection in patients with radiologic complete response after conversion therapy for initially unresectable hepatocellular carcinoma: a propensity score-matching comparative study

BACKGROUND

The optimal subsequent management for patients with initially unresectable hepatocellular carcinoma (uHCC) who have achieved complete response (CR) following conversion therapy remains unclear. This study aims to evaluate the feasibility and outcomes of the watch-and-wait (W-W) strategy versus surgical resection (SR) for these patients.

MATERIALS AND METHODS

This retrospective study reviewed patients with initially uHCC who underwent conversion therapy employing transarterial therapies combined with or without systemic therapies. Radiologic CR (rCR), clinical CR (cCR), and pathologic CR (pCR) were evaluated. Overall survival (OS) and progression-free survival (PFS) were compared between the W-W and SR groups.

RESULTS

Among 1880 patients with uHCC who underwent conversion therapy, 207 (11.0%) achieved rCR. Finally, we enrolled 149 patients meeting the inclusion criteria, including 74 receiving W-W strategy and 75 undergoing SR. Among the 149 patients with rCR, the W-W group demonstrated comparable 3-year OS rates to the SR group (80.9 vs 83.1%, P =0.77), but demonstrated inferior PFS rates (14.4 vs 46.5%, P =0.002). These results remained consistent after propensity score matching. For the 57 patients who achieved cCR, the W-W group exhibited comparable 3-year OS (88.1 vs 87.9%, P =0.89) and PFS rates (27.8 vs 40.8%, P =0.34) compared to SR group. Among the 75 patients in the SR group, 31 (41.3%) achieved pCR and 44 (58.7%) reached non-pCR. When compared with patients with pCR, those who achieved rCR in the W-W group showed comparable OS but inferior PFS rates. Moreover, patients who achieved rCR in the W-W group displayed both comparable OS and PFS rates to those with non-pCR.

CONCLUSION

The W-W strategy offered comparable survival outcomes to SR in patients with initially uHCC who achieved rCR or cCR after conversion therapy. For these patients, the W-W strategy could be offered as an alternative treatment option.

A prospective study on using shear wave elastography to predict the ypT0 stage of rectal cancer after neoadjuvant therapy: a new support for the watch-and-wait approach?

Introduction

The diagnostic accuracy of traditional imaging examination in predicting ypT stage of rectal cancer after neoadjuvant therapy is significantly reduced, which would affect patients' subsequent treatment choices. This study aimed to investigate the use of endorectal shear wave elastography (SWE) for diagnosing ypT0 stage of rectal cancer after neoadjuvant chemoradiotherapy (nCRT).

Methods

Sixty patients with rectal cancer were prospectively recruited in this study. Data on endorectal ultrasound (ERUS) and SWE parameters were collected before nCRT and 6-8 weeks after nCRT. Postoperative pathological results were the gold standard for evaluating the diagnostic accuracy of SWE and ERUS in predicting the ypT0 stage of rectal cancer after nCRT. Receiver operating characteristic (ROC) curve analysis was used to determine the cut-off values of the SWE parameters that best corresponded to the ypT0 stage and analyze the sensitivity, specificity, and accuracy.

Results

The diagnostic accuracies of using ERUS to predict the ypT and ypT0 stages of rectal cancer after nCRT were 58.1% (18/31) and 64.3% (9/14), respectively. The ROC curve was constructed with the lesion's Emean, Emean corrected (EC), Emean difference (ED), Emean corrected differencede (ECD), Emean descendding rate (EDR) and Emean corrected descendding rate (ECDR) values after nCRT, the cut-off values of diagnosing the ypT0 stage were 64.40 kPa, 55.45 kPa, 72.55 kPa, 73.75 kPa, 50.15%, and 55.93%, respectively; the area under the curve (AUC) for diagnosing the ypT0 stage was 0.924, 0.933, 0.748, 0.729, 0.857 and 0.861, respectively. The EC value showed the best diagnostic performance.

Conclusion

SWE could improve the accuracy of conventional ERUS in diagnosing the ypT0 stage of rectal cancer after nCRT. It is expected to become a new method to help predict pathological complete responses in clinical practice and provide new evidence for the watch-and-wait approach.

The efficacy and safety of short-course radiotherapy followed by sequential chemotherapy and Cadonilimab for locally advanced rectal cancer: a protocol of a phase II study

BACKGROUND

For patients with locally advanced rectal cancer (LARC), total neoadjuvant therapy (TNT), namely, intensifying preoperative treatment through the integration of radiotherapy and systemic chemotherapy before surgery, was commonly recommended as the standard treatment. However, the risk of distant metastasis at 3 years remained higher than 20%, and the complete response (CR) rate was less than 30%. Several clinical trials had suggested a higher complete response rate when combining single-agent immunotherapy with short-course radiotherapy (SCRT). The CheckMate 142 study had shown encouraging outcomes of dual immunotherapy and seemingly comparable toxicity for CRC compared with single-agent immunotherapy in historical results. Therefore, dual immunotherapy might be more feasible in conjunction with the TNT paradigm of SCRT. We performed a phase II study to investigate whether the addition of a dual immune checkpoint inhibitor bispecific antibody, Cadonilimab, to SCRT combined with chemotherapy might further increase the clinical benefit and prognosis for LARC patients.

METHODS

This single-arm, multicenter, prospective, phase II study included patients with pathologically confirmed cT3-T4N0 or cT2-4N + rectal adenocarcinoma with an ECOG performance score of 0 or 1. Bispecific antibody immunotherapy was added to SCRT combined with chemotherapy. Patients enrolled would be treated with SCRT (25 Gy in five fractions over 1 week) for the pelvic cavity, followed by 4 cycles of CAPOX or 6 cycles of mFOLFOX and Cadonilimab. The primary endpoint was the CR rate, which was the ratio of the pathological CR rate plus the clinical CR rate. The secondary endpoints included local-regional control, distant metastasis, disease-free survival, overall survival, toxicity profile, quality of life and functional outcome of the rectum. To detect an increase in the complete remission rate from 21.8% to 40% with 80% power, 50 patients were needed.

DISCUSSION

This study would provide evidence on the efficacy and safety of SCRT plus bispecific antibody immunotherapy combined with chemotherapy as neoadjuvant therapy for patients with LARC, which might be used as a candidate potential therapy in the future.

TRIAL REGISTRATION

This phase II trial was prospectively registered at ClinicalTrials.gov, under the identifier NCT05794750.

Evaluating complete response prediction rates in locally advanced rectal cancer with different radiomics segmentation approaches

Purpose

Studies examining prediction of complete response (CR) in locally advanced rectum cancer (LARC) from pre/post chemoradiotherapy (CRT) magnetic resonance imaging (MRI) are performed mostly with segmentations of the tumor, whereas only in two studies segmentation included tumor and mesorectum. Additionally, pelvic extramesorectal region, which is included in the clinical target volume (CTV) of radiotherapy, may contain information. Therefore, we aimed to compare predictive rates of radiomics analysis with features extracted from segmentations of tumor, tumor+mesorectum, and CTV.

Methods and materials

Ninety-three LARC patients who underwent CRT in our institution between 2012 and 2019 were retrospectively scanned. Patients were divided into CR and non-CR groups. Tumor, tumor+mesorectum and CTV were segmented on T2 preCRT MRI images. Extracted features were compared for best area under the curve (AUC) of CR prediction with 15 machine-learning models.

Results

CR was observed in 25 patients (26.8%), of whom 13 had pathological, and 12 had clinical complete response. For tumor, tumor+mesorectum and CTV segmentations, the best AUC were 0.84, 0.81, 0.77 in the training set and 0.85, 0.83 and 0.72 in the test set, respectively; sensitivity and specificity for the test set were 76%, 90%, 76% and 71%, 67% and 62%, respectively.

Conclusion

Although the highest AUC result is obtained from the tumor segmentation, the highest accuracy and sensitivity are detected with tumor+mesorectum segmentation and these findings align with previous studies, suggesting that the mesorectum contains valuable insights for CR. The lowest result is obtained with CTV segmentation. More studies with mesorectum and pelvic nodal regions included in segmentation are needed.

Interdisciplinary Spanish consensus on a watch-and-wait approach for rectal cancer

Watch-and-wait has emerged as a new strategy for the management of rectal cancer when a complete clinical response is achieved after neoadjuvant therapy. In an attempt to standardize this new clinical approach, initiated by the Spanish Cooperative Group for the Treatment of Digestive Tumors (TTD), and with the participation of the Spanish Association of Coloproctology (AECP), the Spanish Society of Pathology (SEAP), the Spanish Society of Gastrointestinal Endoscopy (SEED), the Spanish Society of Radiation Oncology (SEOR), and the Spanish Society of Medical Radiology (SERAM), we present herein a consensus on a watch-and-wait approach for the management of rectal cancer. We have focused on patient selection, the treatment schemes evaluated, the optimal timing for evaluating the clinical complete response, the oncologic outcomes after the implementation of this strategy, and a protocol for surveillance of these patients.