Primary tumor response to preoperative chemoradiation with or without oxaliplatin in locally advanced rectal cancer: pathologic results of the STAR-01 randomized phase III trial

Treatment of Locally Advanced Rectal Cancer in the Era of Total Neoadjuvant Therapy: A Systematic Review and Network Meta-Analysis

Importance

Treatment of locally advanced rectal cancer (LARC) involves neoadjuvant chemoradiotherapy plus total mesorectal excision and adjuvant chemotherapy. However, total neoadjuvant therapy (TNT) protocols (ie, preoperative chemotherapy in addition to radiotherapy) may allow better adherence and early treatment of distant micrometastases and may increase pathological complete response (pCR) rates.

Objective

To assess the efficacy and tolerability of TNT protocols for LARC.

Data Sources

MEDLINE, Embase, Cochrane Central Register of Controlled Trials (CENTRAL), and Web of Science Core Collection electronic databases and ClinicalTrials.gov for unpublished studies were searched from inception to March 2, 2024.

Study Selection

Randomized clinical trials including adults with LARC who underwent rectal resection as a final treatment were included. Studies including nonoperative treatment (watch-and-wait strategy), treatments other than rectal resection, immunotherapy, or antiangiogenic agents were excluded. Among the initially identified studies, 2.9% met the selection criteria.

Data Extraction and Synthesis

Two authors independently screened the records and extracted data. Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA)-compliant pairwise and network meta-analyses with a random-effects model were performed in a frequentist framework, and the certainty of evidence was assessed according to the confidence in network meta-analysis approach.

Main Outcomes and Measures

The primary outcome was pCR, defined as the absence of residual tumor at pathological assessment after surgery. Secondary outcomes included tolerability, toxic effects, perioperative outcomes, and long-term survival.

Results

Of 925 records identified, 27 randomized clinical trials, including 13 413 adults aged 18 years or older (median age, 60.0 years [range, 42.0-63.5 years]; 67.2% male) contributed to the primary network meta-analysis. With regard to pCR, long-course chemoradiotherapy (L-CRT) plus consolidation chemotherapy (relative risk [RR], 1.96; 95% CI, 1.25-3.06), short-course radiotherapy (S-RT) plus consolidation chemotherapy (RR, 1.76; 95% CI, 1.34-2.30), and induction chemotherapy plus L-CRT (RR, 1.57; 95% CI, 1.09-2.25) outperformed standard L-CRT with single-agent fluoropyrimidine-based chemotherapy. Considering 3-year disease-free survival, S-RT plus consolidation chemotherapy (RR, 1.08; 95% CI, 1.01-1.14) and induction chemotherapy plus L-CRT (RR, 1.12; 95% CI, 1.01-1.24) outperformed L-CRT, in spite of an increased 5-year locoregional recurrence rate of S-RT plus consolidation chemotherapy (RR, 1.65; 95% CI, 1.03-2.63).

Conclusions and Relevance

In this systematic review and network meta-analysis, 3 TNT protocols were identified to outperform the current standard of care in terms of pCR rates, with good tolerability and optimal postoperative outcomes, suggesting they should be recognized as first-line treatments.

Future direction of total neoadjuvant therapy for locally advanced rectal cancer

Despite therapeutic advancements, disease-free survival and overall survival of patients with locally advanced rectal cancer have not improved in most trials as a result of distant metastases. For treatment decision-making, both long-term oncologic outcomes and impact on quality-of-life indices should be considered (for example, bowel function). Total neoadjuvant therapy (TNT), comprised of chemotherapy and radiotherapy or chemoradiotherapy, is now a standard treatment approach in patients with features of high-risk disease to prevent local recurrence and distant metastases. In selected patients who have a clinical complete response, subsequent surgery might be avoided through non-operative management, but patients who do not respond to TNT have a poor prognosis. Refined molecular characterization might help to predict which patients would benefit from TNT and non-operative management. Specifically, integrated analysis of spatiotemporal multi-omics using artificial intelligence and machine learning is promising. Three prospective trials of TNT and non-operative management in Japan, the USA and Germany are collaborating to better understand drivers of response to TNT. Here, we address the future direction for TNT.

A deep neural network predictor to predict the sensitivity of neoadjuvant chemoradiotherapy in locally advanced rectal cancer

Neoadjuvant chemoradiotherapy (NCRT) is widely used for locally advanced rectal cancer (LARC). This study aimed to conduct an effective model to predict NCRT sensitivity and provide guidance for clinical treatment. Biomarkers for NCRT sensitivity were identified by applying transcriptome profiles using logistic regression and subsequently screened out by Spearman correlation analysis and four machine learning algorithms. A deep neural network (DNN) predictor was constructed by using in-house dataset and validated in two independent datasets. Additionally, a web-based program was developed. Wnt/β-catenin signaling and linoleic acid metabolism (LA) pathways were associated with NCRT sensitivity and prognosis in LARC, antagonistically. A DNN predictor with an 18-gene signature was conducted within in-house datasets. In two validation cohorts, area under ROC curve (AUC) achieved 0.706 and 0.897. The DNN subtypes were significantly associated with NCRT sensitivity, survival status et al. Moreover, NK and cytotoxic T cells were observed contribution to NCRT sensitivity while regulatory T, myeloid-derived suppressor cells and dysfunction of CD4 T effector memory cells could impede NCRT response. A DNN predictor could predict NCRT sensitivity in LARC and stratify LARC patients with different clinical and immunity characteristic.

The multidisciplinary management of locally advanced rectal cancer

INTRODUCTION

The classic paradigm for the management of locally advanced rectal cancer (LARC) consists of (chemo)radiotherapy (C)RT), total mesorectal excision, and adjuvant chemotherapy (CHT). At present, due to the high rate of distant metastasis (up to 30%), the total neoadjuvant therapy (TNT) with the administration of systemic CHT in the neoadjuvant setting has gained acceptance as standard of care.Our aim is to critically review the current literature on LARC management and summarize the different approaches recently proposed to improve clinical outcomes. It represents a starting step to develop an effective strategy that ultimately could harmonize the standard of care in daily clinical practice.

AREAS COVERED

Studies reporting the impact of TNT approaches were deemed eligible. De-escalation strategies, including non-operative management (NOM) after TNT, as well as RT omission or systemic therapy alone, were also investigated.

EXPERT OPINION

The year 2020 has seen promising new data from randomized phase III trials in the field of LARC management. Nowadays, TNT strategy has been accepted as the primary treatment for LARC. The role of de-escalation strategies is still unknown. The goal is to achieve better survival outcomes with improving quality of life. Only selected patients are likely to benefit from NOM or immunotherapy alone.

Retrospective Evaluation of the Efficacy of Total Neoadjuvant Therapy and Chemoradiotherapy Neoadjuvant Treatment in Relation to Surgery in Patients with Rectal Cancer

Background and Objective: In the therapeutic strategy of rectal cancer, radiotherapy has consolidated its important position and frequent use in current practice due to its indications as neoadjuvant, adjuvant, definitive, or palliative treatment. In recent years, total neoadjuvant therapy (TNT) has been established as the preferred regimen compared to concurrent neoadjuvant chemoradiotherapy (CRT). In relation to better outcomes, the percentage of patients who achieved pathological complete response (pCR) after neoadjuvant treatment is higher in the case of TNT. This study aimed to analyze the response to TNT compared to neoadjuvant CRT regarding pCR rate and the change in staging after surgical intervention. Materials and Methods: We performed a retrospective study on 323 patients with rectal cancer and finally analyzed the data of 201 patients with neoadjuvant treatment, selected based on the inclusion and exclusion criteria. Patients received CRT neoadjuvant therapy or TNT neoadjuvant therapy with FOLFOX or CAPEOX. Results: Out of 157 patients who underwent TNT treatment, 19.74% had pathological complete response, whereas in the group with CRT (n = 44), those with pCR were 13.64%. After neoadjuvant treatment, the most frequent TNM classifications were ypT2 (40.30%) and ypN0 (79.10%). The statistical analysis of the postoperative disease stage, after neoadjuvant therapy, showed that the most frequent changes were downstaging (71.14%) and complete response (18.41%). Only four patients (1.99%) had an upstaging change. The majority of patients (88.56%) initially presented clinical evidence of nodal involvement whereas only 20.9% of the patients still presented regional disease at the time of surgical intervention. Conclusions: By using TNT, a higher rate of stage reduction is obtained compared to the neoadjuvant CRT treatment. The post-neoadjuvant-treatment imagistic evaluation fails to accurately evaluate the response. A better response to TNT was observed in young patients.

Combinatorial Approaches for Chemotherapies and Targeted Therapies With Radiation: United Efforts to Innovate in Patient Care

Combinatorial therapies consisting of radiation therapy (RT) with systemic therapies, particularly chemotherapy and targeted therapies, have moved the needle to augment disease control across nearly all disease sites for locally advanced disease. Evaluating these important combinations to incorporate more potent therapies with RT will aid our understanding of toxicity and efficacy for patients. This article discusses multiple disease sites and includes a compilation of contributions from expert Red Journal editors from each disease site. Leveraging improved systemic control with novel agents, we must continue efforts to study novel treatment combinations with RT.

Role of Oxaliplatin in the Neoadjuvant Concurrent Chemoradiotherapy in Locally Advanced Rectal Cancer: a Review of Evidence

The treatment of locally advanced rectal cancer (LARC) is a challenging situation for radiation oncologists and colorectal surgeons. Most current approaches recommend neoadjuvant fluorouracil or capecitabine-based chemoradiotherapy followed by surgery as a standard of care. Intensification of concurrent chemotherapy by adding oxaliplatin to fluorouracil or capecitabine backbone to get better outcomes is the matter that has remained unresolved. In this review, we searched Medline and Google Scholar databases and selected 28 prospective phase II and III clinical trials that addressed this question. We discussed the potential advantages and drawbacks of incorporating oxaliplatin into concurrent chemoradiation therapy. We tried to define whether adding oxaliplatin to concurrent chemoradiation with excellent performance and high-risk features benefits some subpopulations. The available literature suggests that by adding oxaliplatin there are some benefits in enhancing response to neoadjuvant chemoradiotherapy, however, without any translated improvements in long-term outcomes including overall and disease-free survival.

Radiation therapy of the primary tumour and/or metastases of digestive metastatic cancers

Metastatic gastrointestinal cancer is not an uncommon situation, especially for pancreatic, gastric, and colorectal cancers. In this setting, few data are available on the impact of the treatment of the primary tumour. Oligometastatic disease is associated with longer survival in comparison with more advanced disease. Metastasis-directed therapy, such as stereotactic body radiotherapy, seems related to better outcomes, but the level of evidence is low. In most tumour locations, prospective data are very scarce and inclusion in ongoing trials is strongly recommended.

Adoption of Total Neoadjuvant Therapy in the Treatment of Locally Advanced Rectal Cancer

Local and metastatic recurrence are primary concerns following the treatment of locally advanced rectal cancer (LARC). Chemoradiation (CRT) can reduce the local recurrence rates and has subsequently moved to the neoadjuvant setting from the adjuvant setting. Pathological complete response (pCR) rates have also been noted to be greater in patients treated with neoadjuvant CRT prior to surgery. The standard approach to treating LARC would often involve CRT followed by surgery and optional adjuvant chemotherapy and remained the treatment paradigm for almost two decades. However, patients were often unable to complete adjuvant chemotherapy due to a decreased tolerance of chemotherapy following surgery, which led to upfront treatment with both CRT and chemotherapy, and total neoadjuvant therapy, or TNT, was created. The efficacy outcomes of local recurrence, disease-free survival, and pCR have improved in patients receiving TNT compared to the standard approach. Additionally, more recent data suggest a possible improvement in overall survival as well. Patients with a complete clinical response following TNT have the opportunity for watch-and-wait surveillance, allowing some patients to undergo organ preservation. Here, we discuss the clinical trials and studies that led to the adoption of TNT as the standard of care for LARC, with the possibility of watch-and-wait surveillance for patients achieving complete responses. We also review the possibility of overtreating some patients with LARC.

Quality of Surgical Outcome Reporting in Randomised Clinical Trials of Multimodal Rectal Cancer Treatment: A Systematic Review

INTRODUCTION

Randomised controlled trials (RCTs) continue to provide the best evidence for treatment options, but the quality of reporting in RCTs and the completeness rate of reporting of surgical outcomes and complication data vary widely. The aim of this study was to measure the quality of reporting of the surgical outcome and complication data in RCTs of rectal cancer treatment and whether this quality has changed over time.

METHODS

Eligible articles with the keywords ("rectal cancer" OR "rectal carcinoma") AND ("radiation" OR "radiotherapy") that were RCTs and published in the English, German, Polish, or Italian language were identified by reviewing all abstracts published from 1982 through 2022. Two authors independently screened and analysed all studies. The quality of the surgical outcome and complication data was assessed based on fourteen criteria, and the quality of RCTs was evaluated based on a modified Jadad scale. The primary outcome was the quality of reporting in RCTs and the completeness rate of reporting of surgical results and complication data.

RESULTS

A total of 340 articles reporting multimodal therapy outcomes for 143,576 rectal cancer patients were analysed. A total of 7 articles (2%) met all 14 reporting criteria, 13 met 13 criteria, 27 met from 11 to 12 criteria, 36 met from 9 to 10 criteria, 76 met from 7 to 8 criteria, and most articles met fewer than 7 criteria (mean 5.5 criteria). Commonly underreported criteria included complication severity (15% of articles), macroscopic integrity of mesorectal excision (17% of articles), length of stay (18% of articles), number of lymph nodes (21% of articles), distance between the tumour and circumferential resection margin (CRM) (26% of articles), surgical radicality according to the site of the primary tumour (R0 vs. R1 + R2) (29% of articles), and CRM status (38% of articles).

CONCLUSION

Inconsistent surgical outcome and complication data reporting in multimodal rectal cancer treatment RCTs is standard. Standardised reporting of clinical and oncological outcomes should be established to facilitate comparing studies and results of related research topics.

Retrospective Evaluation of the Impact of Dose Escalation Using Pre-operative Simultaneous Integrated Boost Volumetric Modulated Arc Therapy on the Outcome of Locally Advanced Rectal Cancer Patients

PURPOSE

Evaluating the outcome of pre-operative simultaneous integrated boost volumetric modulated arc therapy (SIB-VMAT) concomitant with capecitabine in patients diagnosed with locally advanced rectal cancer (LARC) at King Faisal Specialist Hospital and Research Centre (KFSH&RC), Riyadh, Saudi Arabia, during the period January 2013-December 2019.

RESULTS

A total of 134 patients were enrolled. The median age at diagnosis was 59 years. All patients received pre-operative concurrent chemo-radiation therapy (CCRT) using SIB-VMAT with oral capecitabine. Neoadjuvant chemotherapy was administered prior to CCRT in 32 patients (23.9%). The dose of radiation was 55 Gy in 94 patients (70.1%), while 40 patients (29.9%) received 50 Gy. All patients completed the CCRT treatment without breaks. No records of acute and late grade III and IV toxicities. Curative surgery was performed in all patients with a median interval of 11 (6-52) weeks between the end of CCRT and the date of surgery. No reported 30-day postoperative mortality and no grade III and IV Clavien-Dindo complications. PCR was reported in 26 patients (19.4%), while pathologically negative nodes (pN0) were achieved in 103 patients (76.9%). Adjuvant chemotherapy was utilized in 57 patients (42.5%). The 5-year local recurrence-free survival (LRFS), disease-free survival (DFS), and overall survival (OS) were 93.2%, 67.1%, and 87.3%, respectively. Only tumor regression grade (TRG) was significantly correlated with LRFS, (p value 0.043). On multivariate analysis, only TRG and achievement of pN0 were significantly correlated with DFS (p value < 0.001).

CONCLUSION

Dose escalation utilization (SIB-VMAT) in the pre-operative treatment of LARC is well tolerated and provides effective local control.

Preoperative Radiotherapy with a Simultaneous Integrated Boost Compared to Chemoradiotherapy for cT3-4 Rectal Cancer: Long-Term Results of a Multicenter Randomized Study

BACKGROUND

Preoperative chemoradiotherapy (CRT) is the standard treatment for T3-4 rectal cancer. Here, we compared image-guided and intensity-modulated RT (IG-IMRT) with a simultaneous integrated boost (SIB) (instead of concomitant chemotherapy) versus CRT in a multi-centric randomized trial.

METHODS

cT3-4 rectal cancer patients were randomly assigned to receive preoperative IG-IMRT 46 Gy/23 fractions plus capecitabine 825 mg/m² twice daily (CRT arm) or IG-IMRT 46 Gy/23 fractions with an SIB to the rectal tumor up to a total dose of 55.2 Gy (RTSIB arm).

RESULTS

A total of 174 patients were randomly assigned between April 2010 and May 2014. Grade 3 acute toxicities were 6% and 4% in the CRT and RTSIB arms, respectively. The mean fractional change in SUVmax at 5 weeks after completion of preoperative RT were -55.8% (±24.0%) and -52.9% (±21.6%) for patients in the CRT arm and RTSIB arm, respectively (p = 0.43). The pathologic complete response rate was 24% with CRT compared to 14% with RTSIB. There were no differences in 5-year overall survival (OS), progression-free survival (PFS) or local control (LC).

CONCLUSIONS

The preoperative RTSIB approach was not inferior to CRT in terms of metabolic response, toxicity, OS, PFS and LC, and could be considered an available option for patients unfit for fluorouracil-based CRT.

Neoadjuvant Modified FOLFOXIRI With Selective Radiotherapy in Locally Advanced Rectal Cancer: Long-term Outcomes of Phase II Study and Propensity-Score-Matched Comparison With Chemoradiotherapy

BACKGROUND

Neoadjuvant modified FOLFOXIRI (folinic acid, 5-fluorouracil, oxaliplatin, and irinotecan) chemotherapy with selective radiotherapy did not compromise pathologic complete response and tumor downstaging in locally advanced rectal cancer.

OBJECTIVE

The study aimed to analyze disease-free survival and local recurrence of neoadjuvant chemotherapy with modified FOLFOXIRI (mFOLFOXIRI).

DESIGN

This was a prospective single-arm phase II study. A propensity score-adjusted method was implemented to compare outcomes against historical controls of chemoradiotherapy.

SETTINGS

The study was conducted at single institutions.

PATIENTS

One hundred 6 patients with stage II and III rectal cancers were included.

INTERVENTION

All patients received neoadjuvant mFOLFOXIRI chemotherapy before total mesorectal excision. Patients with mesorectal fascia-positive or ycT4a/b after reevaluation with MRI received radiation before surgery. Otherwise, immediate total mesorectal excision would be performed.

MAIN OUTCOME AND MEASURES

The primary end point was tumor downstaging (ypStage 0-I) rate, which was reported previously. Disease-free survival and local recurrence rate were the main outcomes for the current study.

RESULTS

After a median follow-up of 43.3 months, the 2-year disease-free survival rate was 85.6% and the 3-year disease-free survival rate was 78.9%. The local recurrence rate was 7.8% after surgery. After propensity score matching, 73 patients were available for comparison in each group. The pathologic complete response rate was 23.3% and 13.7% ( p = 0.14), the proportion of ypStage 0-I was 45.2% vs 39.7% ( p = 0.5), the 3-year disease-free survival was 87.6% vs 75.8% (HR = 0.46; 95% CI, 0.22-0.95, p = 0.037). The local recurrence rate in the mFOLFOXIRI group was 5.5% and in the chemoradiotherapy group was 4.1% ( p = 0.70). Patients receiving mFOLFOXIRI had a lower incidence of anastomotic fistula compared with the chemoradiotherapy group (5.5% vs 17.8%, p = 0.02).

LIMITATIONS

This was a single-arm, nonrandomized phase II study.

CONCLUSIONS

Neoadjuvant mFOLFOXIRI with selective radiotherapy was feasible and safe, and it improved 3-year disease-free survival compared with propensity score-matched historical controls who received chemoradiotherapy. See Video Abstract at http://links.lww.com/DCR/B989 .Trial registration: NCT02217020.

FOLFOXIRI MODIFICADO NEOADYUVANTE CON RADIOTERAPIA SELECTIVA EN CNCER DE RECTO LOCALMENTE AVANZADO RESULTADOS A LARGO PLAZO DEL ESTUDIO DE FASE II Y COMPARACIN EMPAREJADA POR PUNTUACIN DE PROPENSIN CON QUIMIORRADIOTERAPIA

ANTECEDENTES:La quimioterapia neoadyuvante con FOLFOXIRI modificado (ácido folínico, 5-fluoruracilo, oxaliplatino e irinotecan) con radioterapia selectiva no comprometió la respuesta patológica completa ni la reducción del estadio del tumor en el cáncer de recto localmente avanzado.OBJETIVO:El estudio tuvo como objetivo analizar la sobrevida libre de enfermedad y la recurrencia local de la quimioterapia neoadyuvante con FOLFOXIRI modificado (mFOLFOXIRI).DISEÑO:Este fue un estudio prospectivo de fase II de un solo brazo. Se implementó un método ajustado por puntaje de propensión para comparar los resultados con los controles históricos de quimiorradioterapia.ESCENARIO:El estudio se realizó en instituciones individuales.PACIENTES:Se incluyeron 106 pacientes con cáncer de recto en estadio II y III.INTERVENCIÓN:Todos los pacientes recibieron quimioterapia neoadyuvante con mFOLFOXIRI antes de la escisión total del mesorrecto. Los pacientes con fascia mesorrectal positiva o ycT4a/b después de la reevaluación con MRI recibirían radiación antes de la cirugía. En caso contrario, se realizaría una escisión mesorrectal total inmediata.PRINCIPALES RESULTADOS Y MEDIDAS:El criterio principal de valoración fue la tasa de disminución del estadio del tumor (ypEstadio 0-I), que se informó anteriormente. La sobrevida libre de enfermedad y la tasa de recurrencia local son los principales resultados del estudio actual.RESULTADOS:Después de una mediana de seguimiento de 43,3 meses, las tasas de sobrevida libre de enfermedad a 2 y 3 años fueron del 85,6 % y 78,9 %, respectivamente. La tasa de recidiva local fue del 7,8% tras la cirugía. Después del emparejamiento por puntaje de propensión, 73 pacientes estaban disponibles para la comparación en cada grupo. La tasa de respuesta patológica completa fue de 23,3 % y de 13,7 % (p = 0,14), la proporción de ypEstadio 0-I fue del 45,2 % frente al 39,7 % (p = 0,5), la SLE a los 3 años fue del 87,6 % frente al 75,8 % (HR = 0,46, IC del 95 % 0,22-0,95, p = 0,037) y la tasa de recurrencia local fue del 5,5 % y del 4,1 % (p = 0,70) en el grupo de mFOLFOXIRI frente al grupo de quimiorradioterapia, respectivamente. Los pacientes que recibieron mFOLFOXIRI tuvieron una menor incidencia de fístula anastomótica en comparación con el grupo de quimiorradioterapia (5,5 % frente a 17,8 %, p = 0,02).LIMITACIONES:Este fue un estudio de fase II no aleatorizado de un solo brazo.CONCLUSIONES:El mFOLFOXIRI neoadyuvante con radioterapia selectiva fue factible y seguro, y mejoró la SSE a los 3 años en comparación con los controles históricos emparejados por puntaje de propensión que recibieron quimiorradioterapia. Consulte Video Resumen en http://links.lww.com/DCR/B989 . (Traducción-Dr. Felipe Bellolio ).

Radiosensitizing Effects of Irinotecan versus Oxaliplatin Alone and in Combination with 5-Fluorouracil on Human Colorectal Cancer Cells

To date, oxaliplatin and irinotecan are used in combination with 5-flourouracil (5-FU) for metastatic colorectal cancer. In this study it was tested whether oxaliplatin and irinotecan and their combinations with 5-FU have an enhanced effect when treated simultaneously with ionizing radiation. In addition, it should be compared whether one combination therapy is more effective than the other. Colorectal cancer cells (HT-29) were treated with irinotecan or oxaliplatin, both alone and in combination with 5-FU, and subsequently irradiated. The cell growth, metabolic activity and proliferation of cells were investigated, and the clonogenic survival was determined. Furthermore, the assessment of radiation-induced DNA damage and the influence of the drugs and their combinations on DNA damage repair was investigated. Treatment with irinotecan or oxaliplatin in combination with 5-FU inhibited proliferation and metabolic activity as well as clonogenic survival and the DNA damage repair capacity of the tumor cells. The comparison of oxaliplatin and irinotecan with simultaneous irradiation showed the same effect of both drugs. When oxaliplatin or irinotecan was combined with 5-FU, tumor cell survival was significantly lower than with monotherapy; however, there was no superiority of either combination regimen. Our results have shown that the combination of 5-FU and irinotecan is as effective as the combination of 5-FU with oxaliplatin. Therefore, our data support the use of FOLFIRI as a radiosensitizer.

Preoperative chemoradiotherapy using tegafur/uracil, oral leucovorin, and irinotecan (TEGAFIRI) followed by oxaliplatin-based chemotherapy as total neoadjuvant therapy for locally advanced rectal cancer: the study protocol for a phase II trial

BACKGROUND

Total neoadjuvant therapy (TNT) is a novel treatment strategy that is an alternative to preoperative chemoradiotherapy (CRT) for locally advanced rectal cancer (LARC). However, an optimal protocol for TNT has not yet been established. The present study will be an open-label, single-arm, single-center trial to develop a new protocol.

METHODS

Thirty LARC patients at high risk of distant metastasis will receive CRT consisting of long-course radiation, concurrent with tegafur/uracil, oral leucovorin, irinotecan (TEGAFIRI), followed by mFOLFOX-6 or CAPOX before undergoing surgery.

DISCUSSION

Since previous findings showed a high percentage of grade 3-4 adverse events with the TEGAFIRI regimen for CRT and TNT, the primary outcome of this study will be safety and feasibility. Our regimen for CRT consists of the biweekly administration of irinotecan for good patient compliance. The novel combination approach of this treatment may improve the long-term outcomes of LARC.

TRIAL REGISTRATION

Japan Registry of Clinical Trials jRCTs031210660.

Neoadjuvant chemoradiotherapy versus neoadjuvant chemotherapy alone for patients with locally advanced rectal cancer: a propensity-score-matched analysis combined with SEER validation

BACKGROUND

Neoadjuvant therapy followed by radical surgery is recommended for locally advanced rectal cancer (LARC). But radiotherapy can cause potential adverse effects. The therapeutic outcomes, postoperative survival and relapse rates between neoadjuvant chemotherapy (N-CT) and neoadjuvant chemoradiotherapy (N-CRT) patients have rarely been studied.

METHODS

From February 2012 to April 2015, patients with LARC who underwent N-CT or N-CRT followed by radical surgery at our center were included. Pathologic response, surgical outcomes, postoperative complications and survival outcomes (including overall survival [OS], disease-free survival [DFS], cancer-specific survival [CSS] and locoregional recurrence-free survival [LRFS]) were analyzed and compared. Concurrently, the Surveillance, Epidemiology, and End Results Program (SEER) database was used to compare OS in an external source.

RESULTS

A total of 256 patients were input into the propensity score-matching (PSM) analysis, and 104 pairs remained after PSM. After PSM, the baseline data were well matched and there was a significantly lower tumor regression grade (TRG) (P < 0.001), more postoperative complications (P = 0.009) (especially anastomotic fistula, P = 0.003) and a longer median hospital stay (P = 0.049) in the N-CRT group than in the N-CT group. No significant difference was observed in OS (P = 0.737), DFS (P = 0.580), CSS (P = 0.920) or LRFS (P = 0.086) between the N-CRT group and the N-CT group. In the SEER database, patients who received N-CT had similar OS in both TNM II (P = 0.315) and TNM III stages (P = 0.090) as those who received N-CRT.

CONCLUSION

N-CT conferred similar survival benefits but caused fewer complications than N-CRT. Thus, it could be an alternative treatment of LARC.

Neoadjuvant Chemotherapy With CAPOX Versus Chemoradiation for Locally Advanced Rectal Cancer With Uninvolved Mesorectal Fascia (CONVERT): Initial Results of a Phase III Trial

OBJECTIVE

To compare neoadjuvant chemotherapy (nCT) with CAPOX alone versus neoadjuvant chemoradiotherapy (nCRT) with capecitabine in locally advanced rectal cancer (LARC) with uninvolved mesorectal fascia (MRF).

BACKGROUND DATA

nCRT is associated with higher surgical complications, worse long-term functional outcomes, and questionable survival benefits. Comparatively, nCT alone seems a promising alternative treatment in lower-risk LARC patients with uninvolved MRF.

METHODS

Patients between June 2014 and October 2020 with LARC within 12 cm from the anal verge and uninvolved MRF were randomly assigned to nCT group with 4 cycles of CAPOX (Oxaliplatin 130 mg/m2 IV day 1 and Capecitabine 1000 mg/m2 twice daily for 14 d. Repeat every 3 wk) or nCRT group with Capecitabine 825 mg/m² twice daily administered orally and concurrently with radiation therapy (50 Gy/25 fractions) for 5 days per week. The primary end point is local-regional recurrence-free survival. Here we reported the results of secondary end points: histopathologic response, surgical events, and toxicity.

RESULTS

Of the 663 initially enrolled patients, 589 received the allocated treatment (nCT, n=300; nCRT, n=289). Pathologic complete response rate was 11.0% (95% CI, 7.8-15.3%) in the nCT arm and 13.8% (95% CI, 10.1-18.5%) in the nCRT arm ( P =0.33). The downstaging (ypStage 0 to 1) rate was 40.8% (95% CI, 35.1-46.7%) in the nCT arm and 45.6% (95% CI, 39.7-51.7%) in the nCRT arm ( P =0.27). nCT was associated with lower perioperative distant metastases rate (0.7% vs. 3.1%, P =0.03) and preventive ileostomy rate (52.2% vs. 63.6%, P =0.008) compared with nCRT. Four patients in the nCT arm received salvage nCRT because of local disease progression after nCT. Two patients in the nCT arm and 5 in the nCRT arm achieved complete clinical response and were treated with a nonsurgical approach. Similar results were observed in subgroup analysis.

CONCLUSIONS

nCT achieved similar pCR and downstaging rates with lower incidence of perioperative distant metastasis and preventive ileostomy compared with nCRT. CAPOX could be an effective alternative to neoadjuvant therapy in LARC with uninvolved MRF. Long-term follow-up is needed to confirm these results.

Long-term results of a phase 2 study of neoadjuvant chemotherapy with molecularly targeted agents for locally advanced rectal cancer

BACKGROUND

We previously reported the feasibility and efficacy of neoadjuvant chemotherapy without radiotherapy for locally advanced rectal cancer. Here, we report the results of a long-term follow-up study.

METHODS

This was a multi-institutional, prospective phase 2 study of patients with locally advanced rectal cancer. Patients received neoadjuvant chemotherapy with molecularly targeted agents before undergoing total mesorectal excision. Six cycles of modified FOLFOX (mFOLFOX6) with bevacizumab were administered to KRAS-mutant patients, and mFOLFOX6 with cetuximab was administered to KRAS-wild-type patients. Here, we report the secondary end points of overall survival, relapse-free survival, and local recurrence rate.

RESULTS

Sixty patients were enrolled in this study. R0 resection was achieved in 98.3% (59/60) patients, and pathological complete response was achieved in 16.7% (10/60) patients. After a median follow-up of 5.4 years, the 5 year overall survival was 81.6%, the 5 year relapse-free survival was 71.7%, and the 5 year local recurrence rate was 12.6%. None of the patients who achieved pathological complete response developed recurrence within 5 years.

CONCLUSIONS

The use of molecularly targeted agents in the neoadjuvant setting for locally advanced rectal cancer has an acceptable prognosis.

Implications of recent neoadjuvant clinical trials on the future practice of radiotherapy in locally advanced rectal cancer

Over the last two decades, the standard treatment for locally advanced rectal cancer (LARC) has been neoadjuvant chemoradiotherapy plus total mesorectal excision followed by adjuvant chemotherapy. Total neoadjuvant treatment (TNT) and immunotherapy are two major issues in the treatment of LARC. In the two latest phase III randomized controlled trials (RAPIDO and PRODIGE23), the TNT approach achieved higher rates of pathologic complete response and distant metastasis-free survival than conventional chemoradiotherapy. Phase I/II clinical trials have reported promising response rates to neoadjuvant (chemo)-radiotherapy combined with immunotherapy. Accordingly, the treatment paradigm for LARC is shifting toward methods that increase the oncologic outcomes and organ preservation rate. However, despite the progress of these combined modality treatment strategies for LARC, the radiotherapy details in clinical trials have not changed significantly. To guide future radiotherapy for LARC with clinical and radiobiological evidence, this study reviewed recent neoadjuvant clinical trials evaluating TNT and immunotherapy from a radiation oncologist’s perspective.

Patient-derived tumor organoids predict responses to irinotecan-based neoadjuvant chemoradiotherapy in patients with locally advanced rectal cancer

Adding irinotecan to neoadjuvant chemoradiotherapy (nCRT) in locally advanced rectal cancer (LARC) increases the pathologic complete response (pCR) rate but brings more toxicities. Robust biomarkers to predict response to irinotecan-based nCRT are extremely necessary for selecting the right patients. Our previous study suggests that patient-derived tumor organoids (PDTOs) sensitivity to chemoradiotherapy matches patient responses. In this study, we investigated whether PDTOs sensitivity to irinotecan can predict complete response (CR) and survival. Eligible patients receiving irinotecan-based nCRT between April 5, 2017 and December 11, 2020 were enrolled in the training cohort (n = 91) for response prediction and survival analysis. Patients receiving nCRT between February 21, 2021 and September 17, 2021 were included in the validation cohort (n = 27). Predictive performances of irinotecan organoid size ratio (OSR) for CR or pCR were evaluated. The irinotecan-sensitive groups had higher response rates compared with the insensitive groups (training cohort: 71.8% vs 24.4%, P < .0001; validation cohort, 81.8% vs 18.8%, P = .002). Moreover, the irinotecan-sensitive group had higher rates of 3-year disease-free survival (DFS: 71.6% vs 55.5%, P = .034) and distant metastasis-free survival (DMFS, 77.9% vs 57.2%, P = .015) than the irinotecan-insensitive group. 5-FU and irradiation sensitivities failed to predict 3-year DFS (5-FU: 65.4% vs 61.9%, P = .643; irradiation: 84.8% vs 57.8%; P = .072). Performances of irinotecan OSR to predict CR or pCR were good in the training cohort (CR: AUC = 0.828; 95% CI = 0.723-0.932; pCR: AUC = 0.864; 95% CI = 0.759-0.961). The validation showed robust predictive ability (CR: AUC = 0.796, 95% CI = 0.5974-0.9952; pCR: AUC = 0.917, 95% CI = 0.7921-1.0000). Irinotecan sensitivity in PDTOs was a predictive and prognostic factor in LARC.

Preoperative Chemoradiotherapy With Capecitabine With or Without Temozolomide in Patients With Locally Advanced Rectal Cancer: A Prospective, Randomised Phase II Study Stratified by O6-Methylguanine DNA Methyltransferase Status: KCSG-CO17-02

AIMS

To evaluate the clinical efficacy of adding temozolomide (TMZ) to preoperative capecitabine (CAP)-based chemoradiotherapy in patients with locally advanced rectal cancer (LARC) and validate O⁶-methylguanine DNA methyltransferase (MGMT) methylation status as a predictive marker for TMZ combined regimens.

MATERIALS AND METHODS

LARC patients with clinical stage II (cT3-4N0) or III (cT_anyN+) disease were enrolled. They were stratified into unmethylated MGMT (uMGMT) and methylated MGMT (mMGMT) groups by methylation-specific polymerase chain reaction before randomisation and were then randomly assigned (1:1) to one of four treatment arms: uMGMT/CAP (arm A), uMGMT/TMZ + CAP (arm B), mMGMT/CAP (arm C) and mMGMT/TMZ + CAP (arm D). The primary end point was the pathological complete response (pCR) rate.

RESULTS

Between November 2017 and July 2020, 64 patients were randomised. Slow accrual caused early study termination. After excluding four ineligible patients, 60 were included in the full analysis set. The pCR rate was 15.0% (9/60), 0%, 14.3%, 18.8% and 26.7% for the entire cohort, arms A, B, C and D, respectively (P = 0.0498 between arms A and D). The pCR rate was 9.7% in the CAP group (arms A + C), 20.7% in the TMZ + CAP group (arms B + D), 6.9% in the uMGMT group (arms A + B) and 22.6% in the mMGMT group (arms C + D). Grade 1-2 nausea or vomiting was significantly more frequent in the TMZ + CAP treatment groups (arms B + D) than in the CAP treatment groups (arms A + C, P < 0.001) with no difference in grade 3 adverse events. There were no grade 4 or 5 adverse events.

CONCLUSION

The addition of TMZ to CAP-based chemoradiotherapy tended to improve pCR rates, particularly in those with mMGMT LARC. MGMT status may warrant further investigation as a predictive biomarker for chemotherapeutic agents and radiotherapy.

Preoperative Radiochemotherapy in Rectal Cancer: Is There an Impact of Oxaliplatin on Pathologic Complete Response and Survival Rates under "Real World" Conditions?

This study aimed to evaluate the benefit of additional administration of oxaliplatin during fluorouracil-based neoadjuvant radiochemotherapy (nRCT) in terms of pathologic complete remission (pCR), disease-free survival (DFS), and overall survival (OS) in patients with advanced rectal cancer. Between 2006 and 2021, 669 patients (pts) were diagnosed with locally advanced rectal cancer, of whom a total of 414 pts with nRCT were identified and included in the study. A total of 283 pts were treated by nRCT using concurrent chemotherapy with fluorouracil or capecitabine; 131 pts were treated using a combination of fluorouracil or capecitabine and oxaliplatin. Propensity score matching analyses (PSM) with 114 pts in each group were used to balance the patients' characteristics. OS, DFS, pCR-rate, and potential prognostic factors were compared between the two groups. The median follow-up time was 59.5 weeks in the fluorouracil-group and 43 weeks in the fluorouracil/oxaliplatin group (p = 0.003). After PSM, the pCR-rate (including sustained clinical complete remission) was 27% (31/114 pts) in the fluorouracil/oxaliplatin group and 16% (18/114 pts) in the fluorouracil-group (p = 0.033). There was no difference between these two groups for both 10-year OS and DFS neither before nor after PSM, respectively (OS: 72.6% vs. 55.4%, p = 0.066, and 67.8% vs. 55.1%, p = 0.703, and DFS: 44.8% vs. 46.8%, p = 0.134, and 44.7% vs. 42.3%, p = 0.184). Multivariate analysis identified regression grading according to Dworak grade 4 (HR: 0.659; CI: 0.471-0.921; p = 0.015) and age over 60 years (HR: 2.231; CI: 1.245-4.001; p = 0.007) as independent predictors for OS. In conclusion, the addition of oxaliplatin to fluorouracil during nRCT significantly improved pCR-rate without having an impact on survival.

Enhancement of radiation therapy by indoleamine 2,3 dioxygenase 1 inhibition through multimodal mechanisms

BACKGROUND

Indoleamine 2,3-dioxygenase 1 (IDO1) is an enzyme that converts tryptophan to kynurenine. IDO1 expression is found not only in tumor cells but also in immune cells and is associated with tumor proliferation and immune responses. IDO1 inhibitors and radiation may cooperatively suppress tumor proliferation through the alterations in the Wnt/β-catenin pathway, cell cycle, and immune response. We investigated the antitumor effects of combination therapy of an IDO1 inhibitor, 1-methyl tryptophan (1-MT), and radiation on colorectal cancer.

METHODS

In vitro experiments were conducted using human and murine colon cancer cell lines (HCT116, HT-29, and Colon26). Cell growth inhibition was assessed using a MTS assay and Clonogenic assay. Cells were cultured for 48 h with or without 500 µM 1-MT after exposure to radiation (4 Gy). Cell cycle effects and modulation of Wnt/β-catenin pathway were evaluated using western blot analysis, flow cytometry, RT-PCR. Subcutaneous Colon26 tumors in BALB/c mice were treated by oral 1-MT (6 mg/mL) for 2 weeks and/or local radiation (10 Gy/10 fr). Bromodeoxyuridine (BrdU) incorporation in tumor cells and expression of differentiation markers of immune cells were evaluated using immunohistochemistry.

RESULTS

1-MT and a small interfering RNA against IDO1 suppressed proliferation of all cell lines, which was rescued by kynurenine. Clonogenic assay showed that administration of 1-MT improved radiosensitivity by suppressing the Wnt/β-catenin pathway activated by radiation and enhancing cell cycle arrest induced by radiation. Combination therapy showed a further reduction in tumor burden compared with monotherapies or untreated control, inducing the highest numbers of intratumoral CD3 + and CD8 + T cells and the lowest numbers of Foxp3 + and BrdU-positive tumor cells.

CONCLUSIONS

The combination of 1-MT and radiation suppressed colon cancer cells in vitro and in vivo via multiple mechanisms.

A Phase II Study of Preoperative Chemoradiotherapy with Capecitabine Plus Simvastatin in Patients with Locally Advanced Rectal Cancer

PURPOSE

The purpose of this phase II trial was to evaluate whether the addition of simvastatin, a synthetic 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitor, to preoperative chemoradiotherapy (CRT) with capecitabine confers a clinical benefit to patients with locally advanced rectal cancer (LARC).

MATERIALS AND METHODS

Patients with LARC (defined by clinical stage T3/4 and/or lymph node positivity) received preoperative radiation (45-50.4 Gy in 25-28 daily fractions) with concomitant capecitabine (825 mg/m2 twice per day) and simvastatin (80 mg, daily). Curative surgery was planned 4-8 weeks after completion of the CRT regimen. The primary endpoint was pathologic complete response (pCR). The secondary endpoints included sphincter-sparing surgery, R0 resection, disease-free survival, overall survival, the pattern of failure, and toxicity.

RESULTS

Between October 2014 and July 2017, 61 patients were enrolled; 53 patients completed CRT regimen and underwent total mesorectal excision. The pCR rate was 18.9% (n=10) by per-protocol analysis. Sphincter-sparing surgery was performed in 51 patients (96.2%). R0 resection was achieved in 51 patients (96.2%). One patient experienced grade 3 liver enzyme elevation. No patient experienced additional toxicity caused by simvastatin.

CONCLUSION

The combination of 80 mg simvastatin with CRT and capecitabine did not improve pCR in patients with LARC, although it did not increase toxicity.

Total neoadjuvant treatment for MRI-stratified high-risk rectal cancer: a single-center, single-arm, prospective Phase II trial (PKUCH-R02)

Background

Induction chemotherapy combined with neoadjuvant chemoradiotherapy has been recommended for patients with high-risk, locally advanced rectal cancer. However, the benefit of more intensive total neoadjuvant treatment (TNT) is unknown. This study aimed to assess the safety and efficacy of induction chemotherapy combined with chemoradiotherapy and consolidation chemotherapy for magnetic resonance imaging-stratified high-risk rectal cancer.

Methods

This was a single-center, single-arm, prospective Phase II trial in Peking University Cancer Hospital (Beijing, China). Patients received three cycles of induction oxaliplatin and capecitabine (CapeOX) followed by chemoradiotherapy and two cycles of consolidation CapeOX. The primary end point was adverse event rate and the second primary end points were 3-year disease-free survival rate, completion of TNT, and pathological downstaging rate.

Results

Between August 2017 and August 2018, 68 rectal cancer patients with at least one high risk factor (cT3c/3d/T4a/T4b, cN2, mesorectal fascia involvement, or extramural venous invasion involvement) were enrolled. The overall compliance of receiving the entire treatment was 88.2% (60/68). All 68 patients received induction chemotherapy, 65 received chemoradiotherapy, and 61 received consolidation chemotherapy. The Grade 3-4 adverse event rate was 30.8% (21/68). Nine patients achieved clinical complete response and then watch and wait. Five patients (7.4%) developed distant metastasis during TNT and received palliative chemotherapy. Fifty patients underwent surgical resection. The complete response rate was 27.9%. After a median follow-up of 49.2 months, the overall 3-year disease-free survival rate was 69.7%.

Conclusions

For patients with high-risk rectal cancer, this TNT regimen can achieve favorable survival and complete response rates but with high toxicity. However, it is necessary to pay attention to the possibility of distant metastasis during the long treatment period.

Toxicity, Disease Control, and Survival Outcomes of Intensified Preoperative Chemoradiotherapy in Patients with Locally Advanced Rectal Cancer: A Single-Institution Study

Purpose

The standard treatment regimen of preoperative chemoradiotherapy (CRT) for locally advanced rectal cancer (LARC) is still controversial. The purpose of this study was to analyze the efficacy and safety of preoperative intensive CRT in our institution.

Methods

A retrospective data collection and analysis of 181 LARC patients receiving oxaliplatin (85%) of standard doses in capecitabine-based preoperative CRT and two additional cycle of neoadjuvant chemotherapy between the end of concurrent CRT and surgery.

Results

The compliance of the preoperative CRT was satisfactory with 99.4%patients completed radiotherapy and 97.19%patients completed all 2 cycles of concurrent chemotherapy. Except for 20 patients diagnosed clinical complete remission (cCR) managed according to watch and wait strategy, 160 patients received R0 radical surgery. The pathological complete response (pCR) rate was 23.75% (38/160) and tumor regression grade (TRG) 0/1 was 40% (72/180). In terms of tumor downstaging, 89 (55.63%) had T downstaging while 115 (71.88%) had N downstaging. The 1-overall survival (OS),2-OS,3-OS and 5-OS were 98.7%, 96.5%, 91.4% and 81.5%, respectively. The total rate of sphincter preservation was 86.25% (138/160) and the rate of patients with low rectal cancer was 73.0% (54/74) without affecting local control rates and survival rates. Both acute adverse reactions to preoperative CRT and postoperative complications were tolerable and controllable.

Conclusion

In this retrospective study, preoperative intensive CRT of patients with LARC achieved satisfied disease control and survival outcomes and well acquired the sphincter retention rate in recent years in our institution. On the basis of these findings, a Phase III study to definitively test the intensified preoperative CRT strategy is warranted.

Changing patterns of neoadjuvant therapy for locally advanced rectal cancer: A narrative review

Standard treatment for patients with locally advanced rectal cancer has been the multidisciplinary approach of neoadjuvant chemoradiotherapy, followed by total mesorectal excision (TME) and postoperative adjuvant chemotherapy. This reduces the local recurrence rate, but the challenge of distant metastasis still persists. The improvement in treatment approach has always been the focus of clinical research and studies have been conducted worldwide in recent years. On one hand, evidence suggests that increasing the intensity of treatment can result in better tumor regression, for example by adding a second drug to the neoadjuvant chemoradiotherapy, or extending the interval between neoadjuvant therapy and surgery, or incorporating chemotherapy and chemoradiotherapy in the neoadjuvant setting. On the other hand, neoadjuvant immunotherapy and selective omission of neoadjuvant radiotherapy may improve the quality of life of patients. In this article, we review the key clinical research progresses in neoadjuvant therapy for locally advanced rectal cancer, hoping to provide some valuable views on the individualized treatment for rectal cancer.

Predictive Value of the Neutrophil-Lymphocyte Ratio for Tumor Regression Grade and Prognosis of Local Advanced Rectal Cancer Patients Undergoing Neoadjuvant Chemoradiotherapy

PURPOSE

Numerous indicators can be used to predict tumor patients' prognosis and tumor regression grade (TRG). The role of the neutrophil-lymphocyte ratio (NLR) among individuals with locally advanced rectal cancer (LARC) following neoadjuvant chemoradiotherapy (nCRT) hasn't been studied, nevertheless. This study aims to explore the predictive value of the NLR before nCRT (pre-NLR) in TRG and prognosis of LARC patients undergoing nCRT..

METHODS

In this retrospective investigation, 326 LARC patients receiving nCRT in total were included. The link between the pre-NLR and TRG was examined using a logistic regression analysis. A Cox-based nomogram was created in the meanwhile to forecast overall survival (OS). With the use of calibration plots and receiver operating characteristic (ROC) curves, we evaluated the nomogram's predictive capabilities.

RESULTS

The median pre-NLR across 326 patients was 2.2 (interquartile range, IQR: 1.7-2.7). In the logistic regression analysis, only the pre-NLR for TRG in LARC patients receiving nCRT was statistically significant (odds ratio, OR = 0.62, 95% CI: 0.47-0.80, P < 0.001). Pre-NLR, nCRT with surgery interval, ypTNM stage, TRG, vascular invasion, adjuvant chemotherapy, and carbohydrate antigen 19-9 before nCRT were revealed to be OS predictors in the Cox multivariate analysis. According to calibration plots and ROC curves, the predictive nomogram demonstrated high statistical performance on internal validation.

CONCLUSION

This study demonstrated that a lower pre-NLR was probably associated with a greater rate of TRG in LARC patients undergoing nCRT. Furthermore, the pre-NLR was credibly correlated with OS in LARC patients undergoing nCRT. Meanwhile, we constructed a nomogram for predicting the prognosis in LARC patients undergoing nCRT.

Efficacy and safety of different radiotherapy doses in neoadjuvant chemoradiotherapy in patients with locally advanced rectal cancer: A retrospective study

Background

This study aims to compare the efficacy and safety of neoadjuvant chemoradiotherapy (nCRT) with different radiotherapy doses (45Gy and 50.4Gy) in patients with locally advanced rectal cancer (LARC).

Methods

Herein, 120 patients with LARC were retrospectively enrolled between January 2016 and June 2021. All patients underwent two courses of induction chemotherapy (XELOX), chemoradiotherapy, and total mesorectum excision (TME). A total of 72 patients received a radiotherapy dose of 50.4 Gy, while 48 patients received a dose of 45 Gy. Surgery was then performed within 5-12 weeks following nCRT.

Results

There was no statistically significant difference between the baseline characteristics of the two groups. The rate of good pathological response in the 50.4Gy group was 59.72% (43/72), while in the 45Gy group achieved 64.58% (31/48) (P>0.05). The disease control rate (DCR) in the 50.4Gy group was 88.89% (64/72), compared to 89.58% (43/48) in the 45Gy group (P>0.05). The incidence of adverse reactions for radioactive proctitis, myelosuppression, and intestinal obstruction or perforation differed significantly between the two groups (P<0.05). The anal retention rate in the 50.4Gy group was significantly higher in contrast to the 45Gy group (P<0.05).

Conclusions

Patients receiving a radiotherapy dose of 50.4Gy have a better anal retention rate but also a higher incidence of adverse events such as radioactive proctitis, myelosuppression, and intestinal obstruction or perforation, and a comparable prognosis to patients treated with a radiotherapy dose of 45Gy.

Strategies to Optimize Treatment for Locally Advanced Rectal Cancer

Neoadjuvant long-course concurrent chemoradiation plus surgery, followed by optional adjuvant chemotherapy, is a standard of care for locally advanced rectal cancer (LARC). However, this traditional approach has several limitations, including low pathological complete response (pCR) (10-25%), high metastasis rate (30-35%), and highly inconsistent compliance with adjuvant chemotherapy (25-75%). Treatment modalities for LARC have dramatically evolved in recent years. Multiple clinical trials have focused on optimizing strategies to achieve a win-win situation for oncologic outcomes and functions. Here, we review the latest studies into optimizing neoadjuvant treatment for LARC.

Acute toxicities of patients with locally advanced rectal cancer treated with intensified chemoradiotherapy within the CAO/ARO/AIO-12 trial: comparing conventional versus VMAT planning at a single center

In locally advanced rectal cancer (LARC) neoadjuvant chemoradiotherapy is regarded as standard treatment. We assessed acute toxicities in patients receiving conventional 3D-conformal radiotherapy (3D-RT) and correlated them with dosimetric parameters after re-planning with volumetric modulated arc therapy (VMAT). Patients were randomized within the multicenter CAO/ARO/AIO-12 trial and received 50.4 Gy in 28 fractions and simultaneous chemotherapy with fluorouracil and oxaliplatin. Organs at risk (OAR) were contoured in a standardized approach. Acute toxicities and dose volume histogram parameters of 3D-RT plans were compared to retrospectively calculated VMAT plans. From 08/2015 to 01/2018, 35 patients with LARC were treated at one study center. Thirty-four patients were analyzed of whom 1 (3%) was UICC stage II and 33 (97%) patients were UICC stage III. Grade 3 acute toxicities occurred in 5 patients (15%). Patients with acute grade 1 cystitis (n = 9) had significantly higher D_mean values for bladder (29.4 Gy vs. 25.2 Gy, p < 0.01) compared to patients without bladder toxicities. Acute diarrhea was associated with small bowel volume (grade 2: 870.1 ccm vs. grade 0-1: 647.3 ccm; p < 0.01) and with the irradiated volumes V5 to V50. Using VMAT planning, we could reduce mean doses and irradiated volumes for all OAR: D_mean bladder (21.9 Gy vs. 26.3 Gy, p < 0.01), small bowel volumes V5-V45 (p < 0.01), D_mean anal sphincter (34.6 Gy vs. 35.6 Gy, p < 0.01) and D_mean femoral heads (right 11.4 Gy vs. 25.9 Gy, left 12.5 Gy vs. 26.6 Gy, p < 0.01). Acute small bowel and bladder toxicities were dose and volume dependent. Dose and volume sparing for all OAR could be achieved through VMAT planning and might result in less acute toxicities.

Predictors of Definitive Treatment Interruptions of Long-Course Neoadjuvant Chemoradiotherapy in Locally Advanced Rectal Cancer

Introduction To identify predictors of definitive treatment interruptions (DTI) of the neoadjuvant long-course radiotherapy (LCRT) in locally advanced rectal cancer (LARC), and to determine their impact on clinical outcomes. Methods Patients with stage II-III LARC treated between 2009-2018 were retrospectively analyzed (n=101, median FU 49.5 months). Logistic regression models evaluated the impact of relevant clinical variables on grade 3 or greater (G3+) acute toxicity, definitive treatment interruption (DTI), pCR, and definitive ostomy (dOST) rates. The secondary outcomes were LRC, MFS, PFS, CSS, and OS. Results The incidences of grade 3 and 4 toxicities were 25.3%, and 1.1%, respectively. The most common G3+ toxicities were peri-anal dermatitis (14.7%) and diarrhea (7.4%), which were more frequent in females (p=0.040) and tumors close to the anal verge (p=0.019). In this study, 11 patients (10.9%) developed DTI, which was associated with these G3+ events (p<0.001). Resection occurred after 7.1 weeks (median, IQR:6.1-8.9). Downstaging occurred in 57.4% (17.8% pCR), 88% achieved negative margins and the dOST rate was 56.4%. The five-year LRC, MFS, PFS, CSS and OS were: 94.4%, 78.9%, 74.7%, 85.2% and 81.6%, respectively. DTI events did not impact any outcome. The factors associated with loco-regional failure were close/positive margins (p<0.001) and stage ypIII (p=0.002). Conclusions: Tumors close to the anal verge and female sex were associated with increased G3+ toxicity, which was predictive of DTI. The resultant partial/complete omission of the planned boost, however, dose did not increase the chance of LR. Further studies to clarify the benefit and optimal timing to deliver the boost are warranted, especially for positive margins.

Lymph node regression grading of locally advanced rectal cancer treated with neoadjuvant chemoradiotherapy

Neoadjuvant chemoradiotherapy (nCRT) and total rectal mesenteric excision are the main standards of treatment for locally advanced rectal cancer (LARC). Lymph node regression grade (LRG) is an indicator of prognosis and response to preoperative nCRT based on postsurgical metastatic lymph node pathology. Common histopathological findings in metastatic lymph nodes after nCRT include necrosis, hemorrhage, nodular fibrosis, foamy histiocytes, cystic cell reactions, areas of hyalinosis, residual cancer cells, and pools of mucin. A number of LRG systems designed to classify the amount of lymph node regression after nCRT is mainly concerned with the relationship between residual cancer cells and regressive fibrosis and with estimating the number of lymph nodes existing with residual cancer cells. LRG offers significant prognostic information, and in most cases, LRG after nCRT correlates with patient outcomes. In this review, we describe the systematic classification of LRG after nCRT, patient prognosis, the correlation with tumor regression grade, and the typical histopathological findings of lymph nodes. This work may serve as a reference to help predict the clinical complete response and determine lymph node regression in patients based on preservation strategies, allowing for the formulation of more accurate treatment strategies for LARC patients, which has important clinical significance and scientific value.

Statins increase pathological response in locally advanced rectal cancer treated with chemoradiation: a multicenter experience

Aims: To investigate the influence of various concomitant medications on outcomes in patients with locally advanced rectal cancer undergoing neoadjuvant chemoradiation. Materials & methods: The authors retrospectively identified 246 patients from 2003 to 2018, collecting demographic and clinicopathological data of interest. Odds ratio (OR) was used to assess the association between concomitant drugs and outcomes. Results: The authors found an association between statins and a Dworak regression grade of 3-4 (OR = 8.78; p = 0.01). Furthermore, statins were significantly associated with more frequent chemoradiation-related toxicity (OR = 2.39; p = 0.0098) and chemotherapy dose reduction or discontinuation (OR = 2.26; p = 0.03). Conclusion: Despite higher frequency of radiotherapy and chemotherapy interruption or dose reduction, the concomitant use of statins during neoadjuvant chemoradiation proved to be associated with better tumor regression.

Preoperative chemoradiotherapy with capecitabine and triweekly oxaliplatin versus capecitabine monotherapy for locally advanced rectal cancer: a propensity-score matched study

Background

Distant metastasis has been the main failure pattern for locoregionally advanced rectal cancer (LARC) patients, and intensified neoadjuvant chemotherapy has become a popular research topic. The present study aimed to compare the survival outcomes, acute toxicities and surgical complications in LARC patients who received preoperative chemoradiotherapy with triweekly oxaliplatin and capecitabine (triweekly XELOX) or capecitabine.

Methods: Between 2007 and 2017, patients with clinically staged II-III rectal cancer who were treated with preoperative chemoradiotherapy using either triweekly XELOX (oxaliplatin 130 mg/m² plus capecitabine 825 mg/m²) or capecitabine were included. Variables potentially influencing chemotherapy treatment selection were used to generate propensity scores (PS). The association between chemotherapy regimens and survival endpoints, including distant metastasis-free survival (DMFS), overall survival (OS) and disease-free survival (DFS), were evaluated and adjusted with PS. The acute toxicities and surgical complications were also compared.

Results

A total of 810 patients were included in the analysis; 277 (34.2%) patients received triweekly XELOX, and 533 (65.8%) received capecitabine. The pathological complete response (pCR) rates were 20.2 and 19.9% (P = 0.912) for the groups treated with triweekly XELOX and capecitabine, respectively. The 5-year DMFS, OS and DFS with triweekly XELOX versus capecitabine were 75.6% vs. 77.6% (P = 0.555), 79.2% vs. 83.3% (P = 0.101), and 69.9% vs. 73.7% (P = 0.283), respectively. Triweekly XELOX was not associated with an increased risk of severe toxicity during chemoradiotherapy, but it increased the risk of postoperative complications compared to capecitabine. After PS adjustment, the differences between the two groups remained insignificant in pCR rate, survival outcomes, and acute toxicities, and the difference in surgical complications disappeared.

Conclusions

Triweekly XELOX or capecitabine concurrent with neoadjuvant radiotherapy leads to similar long-term survival outcomes, acute toxicities and surgical complications in LARC patients.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-022-09855-z.

Nonoperative Management for Rectal Cancer

The treatment algorithm for locally advanced rectal cancer (LARC) has increased in complexity over the past 10 years. Nonoperative management (NOM) for rectal cancer in patients with clinical complete response (cCR) after neoadjuvant therapy has been gaining acceptance as a potential treatment option for selected LARC patients. The current challenge is to accurately select the patients with an apparent cCR, thereby correctly identifying those would-be appropriate candidates for a NOM strategy. NOM should be part of the treatment discussion of LARC, considering increasing rates of cCR, patient preference, potential quality of life gains, and the potential avoidance of surgical morbidity.

Neoadjuvant concurrent chemoradiotherapy using infusional gemcitabine in locally advanced rectal cancer: A phase II trial

INTRODUCTION

Gemcitabine is a well-known radiosensitizer. Herein, we tested the efficacy and toxicity of preoperative concurrent infusional gemcitabine and radiotherapy in locally advanced rectal cancer.

PATIENTS AND METHODS

This was a phase II, single-arm trial. Eligible patients had a diagnosis of rectal adenocarcinoma with clinical stage T3-T4 and/or nodal involvement, age ≥18 years, and no prior chemotherapy or radiotherapy. Patients received preoperative radiation at a dose of 50.4-54 Gy over 28 days with concurrent infusional gemcitabine administered at a dose of 100 mg/m² over the course of 24 h weekly for 6 weeks. The primary endpoint was pathological complete response (pCR).

RESULTS

Forty patients were recruited. Only one patient did not complete therapy due to death. Eight patients did not undergo surgery, one died, two progressed to nonresectable disease, and five withdrew consent. Five patients progressed prior to surgery, with two having unresectable metastases and three having resectable liver metastases. One was found to have peritoneal metastasis during surgery. Out of the 32 patients who underwent surgery, seven achieved pCR at a rate of 20%. With a median follow-up of 30 months, four additional patients had a distant relapse (one had a subsequent local relapse). The 3-year event-free and overall survival rates were 70% and 85%, respectively. The commonest preoperative grade 3-4 toxicity included lymphopenia (50%), neutropenia (41%), anemia (15%), diarrhea (12%), abdominal pain (12%), and proctitis (8%).

CONCLUSION

Concurrent preoperative chemoradiotherapy using infusional gemcitabine for locally advanced rectal cancer achieved an encouraging degree of local control with manageable toxicity.

SEOM-GEMCAD-TTD clinical guidelines for localized rectal cancer (2021)

The management of localized rectal cancer requires a multidisciplinary approach to optimize outcomes, reduce morbidity and prevent under or overtreatments. While early stages may obtain benefit of local resections without any additional therapies, locally advanced rectal cancer becomes a challenge defining the better sequential strategy of surgery, radiotherapy and chemotherapy. The latest results of international phase III studies have positioned the total neoadjuvant therapy as a potential new standard of care in high risk rectal cancers, however, the best schedule is still not well defined.

Phase I Study of Lenvatinib and Capecitabine with External Radiation Therapy in Locally Advanced Rectal Adenocarcinoma

Background

Neoadjuvant chemoradiation with fluoropyrimidine followed by surgery and adjuvant chemotherapy has been the standard treatment of locally advanced stages II and III rectal cancer for many years. There is a high risk for disease recurrence; therefore, optimizing chemoradiation strategies remains an unmet need. Based on a few studies, there is evidence of the synergistic effect of VEGF/PDGFR blockade with radiation.

Methods

In this phase I, dose-escalation and dose-expansion study, we studied 3 different dose levels of lenvatinib in combination with capecitabine-based chemoradiation for locally advanced rectal cancer.

Results

A total of 20 patients were enrolled, and 19 were eligible for assessment of efficacy. The combination was well tolerated, with an MTD of 24 mg lenvatinib. The downstaging rate for the cohort and the pCR was 84.2% and 37.8%, respectively. Blood-based protein biomarkers TSP-2, VEGF-R3, and VEGF correlated with NAR score and were also differentially expressed between response categories. The NAR, or neoadjuvant rectal score, encompasses cT clinical tumor stage, pT pathological tumor stage, and pN pathological nodal stage and provides a continuous variable for evaluating clinical trial outcomes.

Conclusion

The combination of lenvatinib with capecitabine and radiation in locally advanced rectal cancer was found to be safe and tolerable, and potential blood-based biomarkers were identified.

Clinical Trial Registration

NCT02935309

The Evolving Neoadjuvant Treatment Paradigm for Patients with Locoregional mismatch Repair Proficient Rectal Cancer

OPINION STATEMENT

The standard of care for locally advanced rectal cancer (LARC) has included preoperative chemoradiation, total mesorectal excision surgery and post operative adjuvant chemotherapy based on histopathology. The current therapeutic landscape in LARC has many different options with different directions of travel - depending on the goal of treatment. Enthusiasm for delivering total neoadjuvant therapy (TNT) for patients with locally advanced rectal cancer (LARC) is increasing in the light of recently published randomised phase III trials - RAPIDO and PRODIGE-23. There is a wide diversity of different potential schedules and a multitude of approaches, which include induction neoadjuvant chemotherapy (NACT) with a range of chemotherapy options (CAPEOX, FOLFOX, FOLFOXIRI) and a varying duration of 6-18 weeks, or consolidation NACT. These schedules either precede or follow short-course preoperative radiation therapy (SCPRT) using 5 × 5Gy or long-course chemoradiation (LCCRT) using 45-60Gy respectively. The different strategies of induction and consolidation neoadjuvant chemotherapy have been compared and have similar long-term outcomes, but consolidation chemotherapy may facilitate organ-sparing. The results are driving novel paradigms with both intensification and de-intensification treatment strategies. The ideal combination, sequence or duration of such a TNT approach remains undefined. As yet, there are no robust clinical, genetic, molecular, immune or imaging features (alone or integrated), which either direct or aid these choices. Currently, the selection of neoadjuvant treatment is driven by the impact on avoidance or feasibility of surgery or reducing the risk of metastases rather than prevention of local recurrence. Most believe that TNT will improve overall survival, despite the present lack of evidence. Both the inherent heterogeneity in LARC and the observed range of different responses underline the need for response biomarkers to individually tailor therapy rather than 'a one size fits all' approach.

BRIDGE -1 TRIAL: BReak Interval Delayed surgery for Gastrointestinal Extraperitoneal rectal cancer, a multicentric phase III randomized trial

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The lengthening of the surgical interval has a positive impact on pathological complete response (pCR) rate.

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Lengthening the surgical interval from the end of preoperative chemoradiation is not detrimental to survival outcomes in locally advanced rectal cancer.

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Prospective validation of the impact of surgical interval lengthening on complete response and survival outcomes in a randomized trial.

Design

Methods

Conclusions

Oxaliplatin-based adjuvant chemotherapy rather than fluorouracil-based chemotherapy in rectal cancer is more efficient to decrease distant metastasis and increase survival after preoperative chemoradiotherapy and surgery: a meta-analysis

PURPOSE

The standard treatment of stage II-III rectal cancer is preoperative chemoradiotherapy (CRT), followed by total mesorectal excision (TME). However, the rate of metastasis is still high following this treatment. Therefore, several adjuvant chemotherapy studies have been conducted on reducing subsequent metastases and increasing survival, although there are still no definite conclusions.

METHODS

We searched for published prospective randomized controlled trials comparing adjuvant chemotherapy regimens following standard preoperative CRT and curative surgery in stage II-III rectal cancer. We systematically searched Medline, Embase, and the Cochrane Library for relevant trials done from January 2004 to January 2021. Review Manager (RevMan, version 5.3) was used to analyze the data.

RESULTS

We initially searched 1955 studies. We screened and carefully selected four randomized controlled trials with 2897 patients. Compared to the 5-FU-based regimen group, the oxaliplatin-added regimen group attained a higher 3-year locoregional control rate (relative risk [RR] of 0.64, 95% confidence interval [CI], 0.48-0.86; p = 0.003) and 3-year distant metastasis control rate (RR of 0.82, 95% CI, 0.71-0.95; p = 0.007). The oxaliplatin-added regimen group had significantly increased 3-year disease-free survival with a hazard ratio (HR) of 0.85 (95% CI: 0.74-0.97, p = 0.020), but not overall survival (p = 0.740). Grade 3 or higher acute toxicity rates did not differ between the two groups (p = 0.190).

CONCLUSION

The addition of oxaliplatin to adjuvant therapy for stage II-III rectal cancer following preoperative CRT and TME may increase disease-free survival without significant increases in toxicity, but not overall survival.

Adding Consolidation Capecitabine to Neoadjuvant Chemoradiotherapy for Locally Advanced Rectal Cancer: A Propensity-Matched Comparative Study

Aim

To determine whether adding consolidation capecitabine chemotherapy without lengthening the waiting period influences pathological complete response (pCR) and short-term outcome of locally advanced rectal cancer (LARC) receiving neoadjuvant chemoradiotherapy (NCRT).

Method

Totally, 545 LARC who received NCRT and radical resection between 2010 and 2018 were enrolled. Short-term outcome and pCR rate were compared between patients with and without additional consolidation capecitabine. Logistic analysis was performed to identify predictors of pCR.

Results

After propensity score matching, 229 patients were matched in both NCRT and NCRT-Cape groups. Postoperative morbidity was comparable between groups except for operation time, which is lower in the NCRT group (213.2 ± 67.4 vs. 227.9 ± 70.5, p = 0.025). Two groups achieved similar pCR rates (21.8 vs. 22.7%, p = 1.000). Tumor size (OR = 0.439, p < 0.001), time interval between NCRT and surgery (OR = 1.241, p = 0.003), and post-NCRT carcinoembryonic antigen (OR = 0.880, p = 0.008) were significantly correlated with pCR in patients with LARC. A predictive nomogram was constructed with a C-index of 0.787 and 0.741 on internal and external validation.

Conclusion

Adding consolidation capecitabine chemotherapy without lengthening CRT-to-surgery interval in LARC patients after NCRT does not seem to impact pCR or short-term outcome. A predictive nomogram for pCR was successful, and it could support treatment decision-making.

A Comprehensive Evaluation of the Application of the Halcyon(2.0) IMRT Technique in Long-Course Radiotherapy for Rectal Cancer

Objective: To evaluate if the Halcyon(2.0) Intensity Modulation Radiotherapy (IMRT) technique has an advantage in the long-course rectal cancer radiotherapy. Methods: A total of 20 clinical IMRT plans of Halcyon(2.0) for long-course (2Gy in 25 fractions) rectal cancer radiotherapy were randomly selected. Based on the parameters of these plans, 20 TrueBeam (with the Millennium 120 MLC) plans were redesigned, respectively. The dosimetry indexes, field complexity parameters, the Gamma Passing Rates (GPR), and the delivery time of the 2 groups of plans were obtained as measures of the plan quality, the modulation complexity, the delivery accuracy, and the delivery efficiency. The differences between the 2 groups of parameters were analyzed, with P < .05 means statistically significant. Results: In terms of dosimetry, there was no significant or clinical difference between the 2 groups in critical dosimetry parameters. The Monitor Unit of the Halcyon(2.0) fields is lower than the TrueBeam fields by 26.39, while the modulation complexity score (MCS), the mean aperture area variability (AAV), and the mean leaf sequence variability (LSV) of the Halcyon(2.0) fields were 23.8%, 20%, and 2.3% larger than those of the TrueBeam fields, respectively. Neither the ArcCheck-based GPRs nor the portal-dosimetry-based GPRs in both 3%/3 mm and 2%/2 mm criteria showed the difference between the Halcyon(2.0) fields and the TrueBeam fields. The Pearson correlation coefficient between GPR(2%/2 mm) and MCS of the Halcyon(2.0) fields was 0.335, while that of the TrueBeam fields was 0.502. The mean total delivery time of the TrueBeam plans was 195.55 ± 22.86 s, while that of Halcyon(2.0) was 124.25 ± 10.42 s (P < .001), which was reduced approximatively by 36%. Conclusion: For long-course rectal cancer radiotherapy, the Halcyon(2.0) IMRT plans behave almost the same in dosimetry and delivery accuracy as the TrueBeam plans. However, the lower MU and the field modulation complexity, combined with the higher delivery efficiency, make Halcyon(2.0) a feasible and reliable platform in long-course radiotherapy for the rectal cancer.

Fractal-Based Radiomic Approach to Tailor the Chemotherapy Treatment in Rectal Cancer: A Generating Hypothesis Study

Introduction

The aim of this study was to create a radiomic model able to calculate the probability of 5-year disease-free survival (5yDFS) when oxaliplatin (OXA) is or not administered in patients with locally advanced rectal cancer (LARC) and treated with neoadjuvant chemoradiotherapy (nCRT), allowing physicians to choose the best chemotherapy (CT) regimen.

Methods

LARC patients with cT3–4 cN0 or cT1–4 cN1–2 were treated according to an nCRT protocol that included concomitant CT schedules with or without OXA and radiotherapy dose of 55 Gy in 25 fractions. Radiomic analysis was performed on the T2-weighted (T2-w) MR images acquired during the initial tumor staging. Statistical analysis was performed separately for the cohort of patients treated with and without OXA. The ability of every single radiomic feature in predicting 5yDFS as a univariate analysis was assessed using the Wilcoxon–Mann–Whitney (WMW) test or t-test. Two logistic models (one for each cohort) were calculated, and their performance was assessed using the area under the receiver operating characteristic (ROC) curve (AUC).

Results

A total of 176 image features belonging to four families (morphological, statistical, textural, and fractal) were calculated for each patient. At the univariate analysis, the only feature showing significance in predicting 5yDFS was the maximum fractal dimension of the subpopulation identified considering 30% and 50% as threshold levels (maxFD_30–50). Once the models were developed using this feature, an AUC of 0.67 (0.57–0.77) and 0.75 (0.56–0.95) was obtained for patients treated with and without OXA, respectively. A maxFD_30–50 >1.6 was correlated to a higher 5yDFS probability in patients treated with OXA.

Conclusion

This study suggests that radiomic analysis of MR T2-w images can be used to define the optimal concomitant CT regimen for stage III LARC cancer patients. In particular, by providing an indication of the gross tumor volume (GTV) spatial heterogeneity at initial staging, maxFD_30–50 seems to be able to predict the probability of 5yDFS. New studies including a larger cohort of patients and external validation sets are recommended to verify the results of this hypothesis-generating study.

Factors Predicting Pathological Response to Neoadjuvant Chemoradiotherapy in Rectal Cancer: The Experience of a Single Institution with 269 Patients (STONE-01)

Simple Summary

Neoadjuvant chemoradiotherapy (CRT) followed by total mesorectal excision is currently the standard of care for locally advanced rectal cancer (LARC). This retrospective cohort study evaluated the pathological response after CRT in relation to treatment factors and patient and disease factors in order to find useful indicators to further improve the efficacy of CRT and create tailored therapeutic approaches. To date, the optimal timing for surgery after CRT has not been established. In literature, there are controversial results regarding the risk of higher surgical morbidity and perioperative complications due to delayed surgery. In our study carried out on 269 consecutive LARC patients, among the items analyzed, an interval time from CRT to surgery of >8 weeks was the only independent significant factor for pCR and downstaging.

Abstract

Aims: The aim of this study was to define a potential benefit of pathological complete response rate (pCR) and downstaging rate after neoadjuvant chemoradiotherapy (CRT) in relation to treatment and patient factors in locally advanced rectal cancer. Methods: We performed a retrospective cohort study. Patients were divided according to chemotherapy regimens concurrent to radiotherapy (1-drug vs. 2-drug) and according to the time interval between the end of CRT and surgery (≤8 weeks vs. >8 weeks), as well as in relation to specific relevant clinical factors. Logistic regression was used to estimate the independent factors for pCR and downstaging. Results: 269 patients were eligible for this study. Overall, pCR and downstaging rates were 26% and 75.4%, respectively. Univariate analysis showed that female gender (p = 0.01) and time to surgery >8 weeks (p = 0.04) were associated with pCR; age > 70 years (p = 0.05) and time to surgery >8 weeks (p = 0.002) were correlated to downstaging. At multivariate analysis, interval time to surgery of >8 weeks was the only independent factor for both pCR and downstaging (p = 0.02; OR: 0.5, CI: 0.27–0.93 and p = 0.003; OR: 0.42, CI: 0.24–0.75, respectively). Conclusions: This study indicates that, in our population, an interval time to surgery of >8 weeks is an independent significant factor for pCR and downstaging. Further prospective studies are needed to define the best interval time.

Is There a Benefit of Oxaliplatin in Combination with Neoadjuvant Chemoradiotherapy for Locally Advanced Rectal Cancer? An Updated Meta-Analysis

BACKGROUND

Neoadjuvant fluoropyrimidine (5FU or capecitabine)-based chemoradiotherapy (CRT) has been considered the standard of care for locally advanced rectal cancer (LARC). Whether addition of oxaliplatin (OXP) will further improve clinical outcomes is still unclear.

METHODS

To identify clinical trials combining oxaliplatin in preoperative CRT or perioperative chemotherapy for LARC published until March 2021, we searched PubMed and the Cochrane Library. We also searched for relevant ASCO conference abstracts. The primary endpoint was disease-free survival (DFS). Data were extracted from every study to perform a meta-analysis using Review Manager (version 5.3).

RESULTS

A total of seven randomized clinical trials (ACCORD-12, CARO-AIO-04, FOWARC, JIAO, NSABP, PETACC-6, and STAR-01) with 5782 stage II or III rectal cancer patients were analyzed, including 2727 patients with OXP + 5FU regimen and 3055 patients with 5FU alone. Compared with the 5FU alone group, the OXP + 5FU regimen improved DFS (HR = 0.90, 95% CI: 0.81-0.99, p = 0.03) and pathologic complete response (pCR) (OR = 1.21, 95% CI: 1.07-1.37, p = 0.002). Patients treated with the OXP + 5FU regimen had significantly less metastatic progression (OR = 0.79; 95% CI, 0.67 to 0.94; p = 0.007). Considering adverse events (AEs), there was more grade 3-4 diarrhea with OXP + 5FU (OR = 2.41, 95% CI: 1.74-3.32, p < 0.00001). However, there were no significant differences grade 3-4 hematologic AEs (OR = 1.16, 95% CI: 0.87-1.57, p = 0.31).

CONCLUSIONS

Our meta-analysis with long-term results from the randomized studies showed a benefit of the addition of OXP + 5FU regiment in terms of DFS, metastatic progression, and pCR rate that did not translate to improved OS.

Current status of total neoadjuvant therapy for locally advanced rectal cancer

Neoadjuvant chemoradiotherapy (nCRT) plus total mesorectal excision (TME) has been the standard regimen for treatment of patients with locally advanced rectal cancer (LARC), because it significantly reduces the rate of local recurrence and enables sphincter preservation. However, distant metastasis remains the major reason for treatment failure, and the value of postoperative chemotherapy is still controversial. Recent studies have examined the use of total neoadjuvant therapy (TNT), defined as induction and/or consolidation chemotherapy (CONCT) with radiotherapy (RT) or nCRT prior to surgery. The results indicated that TNT may increase the rates of chemotherapy compliance and pathological complete response (pCR), and probably improve the success rate of sphincter preservation surgery. TNT may also improve disease-free survival and overall survival, and even reduce the rate of relapse. Here, we critically appraise the existing literature on three different TNT schemes used for LARC patients.