An observational study of extending FOLFOX chemotherapy, lengthening the interval between radiotherapy and surgery, and enhancing pathological complete response rates in rectal cancer patients following preoperative chemoradiotherapy

Smoking and Elevated Preneoadjuvant Chemoradiotherapy Serum Carcinoembryonic Antigen Levels Are Associated With High Tumor Regression Grade and Poor Survival in Patients With Locally Advanced Rectal Cancer

Neoadjuvant chemoradiotherapy (NACRT) is the standard treatment for patients with locally advanced rectal cancer (LARC). Tumor regression grade (TRG) is an essential prognostic factor in determining treatment efficacy. However, the potential factors influencing TRG in patients with rectal cancer who have received NACRT have not been investigated. We conducted a retrospective analysis of patients with LARC who received NACRT followed by surgical resection. We collected data on the patient characteristics, including age, sex, comorbidities, tumor size, lymph node status, time between NACRT and surgery, and pretreatment carcinoembryonic antigen (CEA) levels. TRG was determined on the basis of a pathological assessment of resected specimens, and overall survival (OS) at 5 years was determined. Univariate and multivariate logistic regression models were employed to evaluate the association between the patient characteristics and TRG. Univariate analysis revealed that smoking and prechemoradiotherapy (pre-CRT) and preoperative CEA levels were significantly associated with TRG. In a multivariate analysis, both smoking and higher pre-CRT CEA levels were identified as significant predictors of a high TRG. The hazard ratios were 2.32 (95% confidence interval [CI]: 1.06-5.07, p = 0.036) for smoking and 3.1 (95% CI: 1.69-5.68, p < 0.001) for higher pre-CRT CEA levels. In Kaplan-Meier analysis, the nonsmoker group exhibited higher OS (p = 0.004). Elevated pre-CRT CEA levels and current smoking status were associated with a more than two fold increase in the risk of a higher TRG after NACRT. Moreover, smoking was a significant risk factor for poor OS in patients with LARC following NACRT.

Prediction and validation of pathologic complete response for locally advanced rectal cancer under neoadjuvant chemoradiotherapy based on a novel predictor using interpretable machine learning

BACKGROUND

Precise evaluation of pathological complete response (pCR) is essential for determining the prognosis of patients with locally advanced rectal cancer (LARC) undergoing neoadjuvant chemoradiotherapy (NCRT) and can offer clues for the selection of subsequent treatment strategies. Most current predictive models for pCR focus primarily on pre-treatment factors, neglecting the dynamic systemic changes that occur during neoadjuvant chemoradiotherapy, and are constrained by low accuracy and lack of integrity.

PURPOSE

This study devised a novel predictor of pCR using dynamic alterations in systemic inflammation-nutritional marker indexes (SINI) during neoadjuvant therapy and developed a machine-learning model to predict pCR.

METHODS

Two cohorts of patients with LARC from center one from 2012 to 2017 and from center two from 2020 to 2023 were integrated for analysis. This study compared dynamic changes in blood indexes before and after neoadjuvant therapy and surgical operation. A least absolute shrinkage and selection operator (LASSO) regression analysis was conducted to mitigate collinearity and identify key indexes, constructing the SINI. Univariate and multiple logistic regression analyses were used to identify the independent risk factors associated with pCR. Additionally, 10 machine learning algorithms were employed to develop predictive models to assess risk. The hyperparameters of the machine learning models were optimized using a random search and 10-fold cross-validation. The models were assessed by examining various metrics, including the area under the receiver operating characteristic curves (AUC), the area under the precision-recall curve (AUPRC), decision curve analysis, calibration curves, and the precision and accuracy of the internal and external validation cohorts. Additionally, Shapley's additive explanations (SHAP) were employed to interpret the machine learning models.

RESULTS

The study cohort comprised 677 patients from the center one and 224 patients from the center two. Six key indexes were identified, and a predictive index, SINI, was constructed. Univariate and multiple logistic regression analyses revealed that SINI, clinical T-stage, clinical N-stage, tumor size, and the distance from the anal verge were independent risk factors for pCR in patients with LARC following NCRT. The mean AUC value of the extreme gradient boosting (XGB) model in the 10-fold cross-validation of the training set was 0.877. The XGB model demonstrated superior performance in the internal and external validation sets. Specifically, in the internal test set, the XGB model achieved an AUC of 0.86, AUPRC of 0.707, accuracy of 0.82, and precision of 0.80. In the external validation set, the XGB model exhibited an AUC of 0.83, AUPRC of 0.702, accuracy of 0.81, and precision of 0.81. Additionally, the predictions generated by the XGB model were analyzed using SHAP.

CONCLUSION

This study involved developing and validating an XGB model using SINI to predict pCR in patients with LARC. Besides, a SINI-based machine learning model shows promise in accurately predicting pCR following NCRT in patients with resectable LARC, offering valuable insights for personalized treatment approaches.

Is ypTNM staging a comparable predictor as pTNM staging for survival in non-metastatic rectal cancer after preoperative chemoradiation therapy?

Background: The pTNM staging system is widely recognized as the most effective prognostic indicator for cancer. The latest update of this staging system introduced a new pathological staging system (ypTNM) for patients receiving neoadjuvant chemoradiotherapy (NACRT). However, whether the prognostic value of the ypTNM staging system for rectal cancer is similar to that of the pTNM staging system remains unclear. This study was conducted to compare the ypTNM and pTNM staging systems in terms of their prognostic value for patients with nonmetastatic rectal cancer undergoing proctectomy. Material and Methods: This study was conducted at a large teaching hospital. Between January 2014 and December 2022, 542 patients with rectal cancer were analyzed (median follow-up period, 60 months; range, 6-105 months). Of them, 258 and 284 were included in the pTNM and ypTNM groups, respectively. Inverse probability of treatment weighting (IPTW) was performed to account for the effects of confounders. Cox proportional-hazards regression was performed for the between-group comparison of overall survival (OS). Results: The crude model revealed that OS was similar between the two groups (p = 0.607). After performing IPTW, we found that patients with the same ypTNM- and pTNM-classified stages had similar overall survival (hazard ratio = 1.15; 95% CI = 0.76-1.73; p = 0.5074). Conclusions: For patients with rectal cancer who have received preoperative NACRT, the prognostic value of ypTNM staging appears to be similar to that of pTNM staging, mostly because of the downstaging effect of neoadjuvant chemoradiotherapy.

Efficacy of concurrent radiotherapy in patients with locally advanced rectal cancer and synchronous metastasis receiving systemic therapy

BACKGROUND

Neoadjuvant chemoradiotherapy followed by total mesorectal excision is the standard treatment for patients with nonmetastatic locally advanced rectal cancer (LARC). However, for patients with LARC and synchronous metastasis, the optimal treatment strategy and sequence remain inconclusive. In the present study, we evaluated the efficacy and safety of concurrent radiotherapy in patients with de novo metastatic rectal cancer who received chemotherapy and targeted therapy.

METHODS

We retrospectively reviewed the data of 63 patients with LARC and synchronous metastasis who received intensive therapy at the study hospital between April 2015 and November 2018. The included patients were divided into two groups: RT-CT, those who received systemic chemotherapy with targeted therapy and concurrent radiotherapy (for primary rectal cancer), and CT, those who received only systemic chemotherapy with targeted therapy.

RESULTS

Treatment response was better in the RT-CT group than in the CT group. The rate of primary tumor resection (PTR) was higher in the RT-CT group than in the CT group (71.4% and 42.9%, respectively; P = .0286). The RT-CT group exhibited considerably longer local recurrence-free survival (P = .0453) and progression-free survival (PFS; from 13.3 to 22.5 months) than did the CT group (P = .0091); however, the groups did not differ in terms of overall survival (OS; P = .49). Adverse events were almost similar between the groups, except frequent diarrhea, the prevalence of which was higher in the RT-CT group than in the CT group (59.5% and 23.8%, respectively; P = .0075).

CONCLUSIONS

In the era of biologics, radiotherapy may increase the resectability of primary rectal tumors, reducing the risk of locoregional failure and prolonging PFS. Concurrent pelvic radiotherapy may not substantially improve OS, which is indicated by metastasis. Hence, the resection of the distant metastases may be essential for improving long-term OS. To further determine the efficacy of concurrent radiotherapy, additional prospective, randomized studies must combine preoperative pelvic radiotherapy with PTR and metastectomy to treat patients with stage IV LARC.

MicroRNAs as Predictive Biomarkers in Patients with Colorectal Cancer Receiving Chemotherapy or Chemoradiotherapy: A Narrative Literature Review

Colorectal cancer (CRC) is one of the most common malignancies and is associated with high mortality rates worldwide. The underlying mechanism of tumorigenesis in CRC is complex, involving genetic, lifestyle-related, and environmental factors. Although radical resection with adjuvant FOLFOX (5-fluorouracil, leucovorin, and oxaliplatin) chemotherapy and neoadjuvant chemoradiotherapy have remained mainstays of treatment for patients with stage III CRC and locally advanced rectal cancer, respectively, the oncological outcomes of these treatments are often unsatisfactory. To improve patients' chances of survival, researchers are actively searching for new biomarkers to facilitate the development of more effective treatment strategies for CRC and metastatic CRC (mCRC). MicroRNAs (miRs), small, single-stranded, noncoding RNAs, can post-transcriptionally regulate mRNA translation and trigger mRNA degradation. Recent studies have documented aberrant miR levels in patients with CRC or mCRC, and some miRs are reportedly associated with chemoresistance or radioresistance in CRC. Herein, we present a narrative review of the literature on the roles of oncogenic miRs (oncomiRs) and tumor suppressor miRs (anti-oncomiRs), some of which can be used to predict the responses of patients with CRC to chemotherapy or chemoradiotherapy. Moreover, miRs may serve as potential therapeutic targets because their functions can be manipulated using synthetic antagonists and miR mimics.

The effect of Mitomycin-C in neoadjuvant concurrent chemoradiotherapy for rectal cancer

BACKGROUND

Neoadjuvant concurrent chemoradiotherapy (nCCRT) followed by total mesorectal excision has become the standard of care for advanced rectal cancer, but the most effective regimen of chemotherapeutic agents has not yet been determined. The purpose of this study is to determine the effect of Mitomycin-C (MMC) in nCCRT for rectal cancer.

METHODS

From 2000 to 2017, patients with rectal adenocarcinoma who received nCCRT followed by radical surgery were enrolled in our study. The patients were retrospectively separated into two groups according to nCCRT regimens (with or without MMC). Other factors related to cancer down-staging after nCCRT, disease-free survival (DFS) and overall survival (OS) were analyzed.

RESULTS

One hundred ninety-five patients received radiotherapy (RT) + MMC + oral tegafur-uracil (UFUR), and 191 patients received RT + UFUR without MMC as neoadjuvant CCRT. Adding MMC might increase the down-staging rate (odds ratio [OR] = 1.520, p = 0.058), and down-staging had significant effect to improve OS (OR = 1.726, p = 0.002) and DFS (OR = 2.185, p < 0.001). The OS and DFS were improved in patients who received MMC, although this result did not reach a statistically significant difference. There was a higher incidence of low-grade toxicities in the MMC group, especially neutropenia, genitourinary side effects, and dermatological side effects ( p < 0.001).

CONCLUSION

Adding MMC to the regimen of nCCRT for rectal adenocarcinoma is shown to increase tumor down-staging rate and improve disease-free and OS, although these benefits come at the cost of increased low-grade toxicities. Prospective randomized studies are needed to explore the role of MMC in nCCRT for rectal cancer.

Critical reappraisal of neoadjuvant concurrent chemoradiotherapy for treatment of locally advanced colon cancer

BACKGROUND

Locally advanced colon cancer (LACC) is associated with surgical challenges during R0 resection, increased postoperative complications, and unfavorable treatment outcomes. Neoadjuvant concurrent chemoradiotherapy followed by surgical resection is an effective treatment strategy that can increase the complete surgical resection rate and improve the patient survival rate. This study investigated the efficacy and toxicity of concurrent chemoradiotherapy in patients with LACC as well as the prognosis and long-term clinical outcomes of these patients.

MATERIALS

From January 2012 to July 2020, we retrospectively reviewed the real-world data of 75 patients with LACC who received neoadjuvant concurrent chemoradiotherapy. The chemotherapy regimen consisted of folinic acid, 5-fluorouracil, and oxaliplatin (FOLFOX). The following data were obtained from medical records: patients' characteristics, pathologic results, toxicity, and long-term oncologic outcome.

RESULTS

Of the 75 patients, 13 (17.3%) had pathologic complete responses. Hematologic adverse effects were the most common (grade 1 anemia: 80.0% and leukopenia: 82.7%). Conversely, grade 2 or 3 adverse effects were relatively uncommon (<10%). Pathologic N downstaging, ypT0, and pathologic complete responses were significant prognostic factors for patient survival. Multivariate analysis revealed that pathologic N downstaging was an independent predictor of patients' overall survival (P = 0.019). The estimated 5-year overall and disease-free survival rates were 68.6% and 50.6%, and the medians of overall and disease-free survival periods were 72.3 and 58.7 months, respectively. Moreover, patients with pathologic complete responses had improved overall survival (P = 0.039) and an improved local recurrence control rate (P = 0.042) but an unfavorable distant metastasis control rate (P = 0.666) in the long-term follow-up.

CONCLUSION

The long-term oncologic outcome of patients with LACC following concurrent chemoradiotherapy is acceptable, and the adverse effects seem to be tolerable. Pathologic N downstaging was an independent prognostic factor for patients' overall survival. However, a large prospective, randomized control study is required to confirm the current results.

miRNA-148a Enhances the Treatment Response of Patients with Rectal Cancer to Chemoradiation and Promotes Apoptosis by Directly Targeting c-Met

Patients with locally advanced rectal cancer (LARC) who achieve a pathological complete response (pCR) to neoadjuvant chemoradiotherapy (NACRT) have an excellent prognosis, but only approximately 30% of patients achieve pCR. Therefore, identifying predictors of pCR is imperative. We employed a microRNA (miRNA) microarray to compare the miRNA profiles of patients with LARC who achieved pCR (pCR group, n = 5) with those who did not (non-pCR group, n = 5). The validation set confirmed that miRNA-148a was overexpressed in the pCR group (n = 11) compared with the non-pCR group (n = 40). Cell proliferation and clonogenic assays revealed that miRNA-148a overexpression radio-sensitized cancer cells and inhibited cellular proliferation, before and after irradiation (p < 0.01). Apoptosis assays demonstrated that miRNA-148a enhanced apoptosis before and after irradiation. Reporter assays revealed that c-Met was the direct target gene of miRNA-148a. An in vivo study indicated that miRNA-148a enhanced the irradiation-induced suppression of xenograft tumor growth (p < 0.01). miRNA-148a may be a biomarker of pCR following NACRT and can promote apoptosis and inhibit proliferation in CRC cells by directly targeting c-Met in vitro and enhancing tumor response to irradiation in vivo.

Pretreatment Neutrophil-to-Lymphocyte Ratio Associated with Tumor Recurrence and Survival in Patients Achieving a Pathological Complete Response Following Neoadjuvant Chemoradiotherapy for Rectal Cancer

The clinical influence of the neutrophil-to-lymphocyte ratio (NLR) in predicting outcomes in patients with locally advanced rectal cancer (LARC) who achieve a pathological complete response (pCR) to neoadjuvant chemoradiotherapy (NACRT) has seldom been investigated. We retrospectively recruited 102 patients with LARC who achieved a pCR to NACRT and the association of NLR status with survival and tumor recurrence in the patients was analyzed. Thirteen patients (12.7%) developed tumor recurrence. A high NLR (≥3.2) was significantly associated with tumor recurrence (p = 0.039). The 5-year OS rates in patients with a low NLR and patients with a high NLR were 95.1% and 77.7%, respectively (p = 0.014); the 5-year DFS rates in patients with low NLR and patients with a high NLR were 90.6% and 71.3%, respectively (p = 0.031). The Cox proportional hazards model indicated that an NLR of ≥3.2 was an independent poor prognostic factor for DFS (hazard ratio [HR] = 3.12, 95% confidence interval [CI] = 1.06-9.46, p = 0.048) and OS (HR = 6.96, 95% CI = 1.53-35.51, p = 0.013). A pretreatment high NLR (≥3.2) was a promising predictor of reduced OS and DFS in patients with LARC who achieved a pCR to NACRT.

Oncological outcomes of robotic-assisted total mesorectal excision after neoadjuvant concurrent chemoradiotherapy in patients with rectal cancer

AIMS

This study analyzed the oncological outcomes of robotic-assisted total mesorectal excision (TME) in patients with rectal cancer after neoadjuvant concurrent chemoradiotherapy (CCRT).

METHODS

We enrolled 109 consecutive patients with stage II-III rectal cancer who underwent robotic-assisted TME after neoadjuvant CCRT at one hospital between July 2013 and June 2018.

RESULTS

All 109 patients underwent preoperative CCRT. Of them, 37 (33.9%) achieved a pathologic complete response, and 29 (26.6%) experienced relapse, with local recurrence in 9 (8.3%) and distant metastasis in 20 (18.3%). R0 resection was performed in 104 (95.7%) patients; however, 7 (6.7%) of them developed local recurrence and 17 (16.3%) developed distant metastasis. Over a median follow-up of 42 months, the 3-year disease-free survival and overall survival rates were 73.4% and 87.2%, respectively.

CONCLUSIONS

Robotic-assisted TME after neoadjuvant CCRT is safe and effective for treating patients with stage II-III rectal cancer in one institution with acceptable short-term oncological outcomes. It may be a therapeutic alternative to salvage surgery for T4 tumors invading adjacent organs, such as the bladder, prostate, and uterus.

Computertomography-Based Prediction of Complete Response Following Neoadjuvant Chemoradiotherapy of Locally Advanced Rectal Cancer

Therapeutic strategies for patients with locally advanced rectal cancer (LARC) who are achieving a pathological complete response (pCR) after neoadjuvant radio-chemotherapy (neoCRT) are being increasingly investigated. Recent trials challenge the current standard therapy of total mesorectal excision (TME). For some patients, the treatment strategy of “watch-and-wait” seems a preferable procedure. The key factor in determining individual treatment strategies following neoCRT is the precise evaluation of the tumor response. Contrast-enhanced computer tomography (ceCT) has proven its ability to discriminate benign and malign lesions in multiple cancers. In this study, we retrospectively analyzed the ceCT based density of LARC in 30 patients, undergoing neoCRT followed by TME. We compared the tumors´ pre- and post-neoCRT density and correlated the results to the amount of residual vital tumor cells in the resected tissue. Overall, the density decreased after neoCRT, with the highest decrease in patients achieving pCR. Densitometry demonstrated a specificity of 88% and sensitivity of 68% in predicting pCR. Thus, we claim that ceCT based densitometry is a useful tool in identifying patients with LARC who may benefit from a “watch-and-wait” strategy and suggest further prospective studies.

Feasibility of robot-assisted surgery in elderly patients with rectal cancer

BACKGROUND

Although surgical resection is the main treatment for rectal cancer, the optimal surgical protocol for elderly patients with rectal cancer remains controversial. This study evaluated the feasibility of robot-assisted surgery in elderly patients with rectal cancer.

PATIENTS AND METHODS

This retrospective study enrolled 156 patients aged 28-93 years diagnosed with Stage I-III rectal cancer, who underwent robot-assisted surgery between May 2013 and December 2018 at a single institution.

RESULTS

In total, 156 patients with rectal cancer, including 126 non-elderly (aged < 70 years) and 30 elderly (aged ≥70 years) patients, who underwent robot-assisted surgery were recruited. Between the patient groups, the post-operative length of hospital stay did not differ statistically significantly (P = 0.084). The incidence of overall post-operative complications was statistically significantly lower in the elderly group (P = 0.002). The disease-free and overall survival did not differ statistically significantly between the two groups (P = 0.719 and 0.390, respectively).

CONCLUSIONS

Robot-assisted surgery for rectal cancer was well tolerated by elderly patients, with similar results to the non-elderly patients. Oncological outcomes and survival did not depend on patient age, suggesting that robot-assisted surgery is a feasible surgical modality for treating operable rectal cancer and leads to age-independent post-operative outcomes in elderly patients.

Curative therapy for rectal cancer

Introduction: A comprehensive trimodality approach has become the standard of care for patients with locally advanced rectal cancer. However, the sequencing and duration of chemotherapy and chemoradiotherapy around surgery varies between clinical studies and geographical regions. Growing evidence is also mounting for strategies such as total neoadjuvant therapy and non-operative management for carefully selected patients.Areas covered: We provide a perspective review of the current evidence and controversies in the treatment of locally advanced rectal cancer including the recent updates from the 2020 ASCO annual conference.Expert opinion: With ongoing advances in the management of locally advanced rectal cancer, a multidisciplinary team approach is necessary as treatments could involve multiple approaches. Chemoradiotherapy whether short or long course followed by at least 3 months of systemic chemotherapy may be the preferred option to balance local and distant disease control. Albeit the choice of doublet or triplet chemotherapy is still controversial. As total neoadjuvant treatment becomes part of the standard of care in rectal cancer, modification of the surveillance schedule is needed to detect early recurrences which may be limited by resources and availability of services.

Outcomes of neoadjuvant chemoradiotherapy followed by radical resection for T4 colorectal cancer

BACKGROUND

Patients with clinical T4 colorectal cancer (CRC) have a poor prognosis because of compromised surgical margins. Neoadjuvant therapy may be effective in downstaging tumors, thereby rendering possible radical resection with clear margins.

AIM

To evaluate tumor downsizing and resection with clear margins in T4 CRC patients undergoing neoadjuvant concurrent chemoradiotherapy followed by surgery.

METHODS

This study retrospectively included 86 eligible patients with clinical T4 CRC who underwent neoadjuvant concurrent chemoradiotherapy followed by radical resection. Neoadjuvant therapy consisted of radiation therapy at a dose of 45-50.4 Gy and chemotherapy agents, either FOLFOX or capecitabine. A circumferential resection margin (CRM) of < 1 mm was considered to be a positive margin. We defined pathological complete response (pCR) as the absence of any malignant cells in a specimen, including the primary tumor and lymph nodes. A multivariate logistic regression model was used to identify independent predictive factors for pCR.

RESULTS

For 86 patients who underwent neoadjuvant chemoradiotherapy and surgery, the rate of pCR was 14%, and the R0 resection rate was 91.9%. Of the 61 patients with rectal cancer, 7 (11.5%) achieved pCR and 5 (8.2%) had positive CRMs. Of the 25 patients with colon cancer, 5 (20%) achieved pCR and 2 (8%) had positive CRMs. We observed that the FOLFOX regimen was an independent predictor of pCR (P = 0.046). After a median follow-up of 47 mo, the estimated 5-year overall survival (OS) and disease-free survival (DFS) rates were 70.8% and 61.4%, respectively. Multivariate analysis revealed that a tumor with a negative resection margin was associated with improved DFS (P = 0.014) and OS (P = 0.001). Patients who achieved pCR exhibited longer DFS (P = 0.042) and OS (P = 0.003) than those who did not.

CONCLUSION

Neoadjuvant concurrent chemoradiotherapy engenders favorable pCR and R0 resection rates among patients with T4 CRC. The R0 resection rate and pCR are independent prognostic factors for patients with T4 CRC.

Impact of previous abdominal surgery on robotic-assisted rectal surgery in patients with locally advanced rectal adenocarcinoma: a propensity score matching study

BACKGROUND

The application of minimally invasive surgery in patients with colorectal cancer (CRC) and a history of previous abdominal surgery (PAS) remains controversial. This retrospective study with propensity score matching (PSM) investigated the impact of PAS on robotic-assisted rectal surgery outcomes in patients with locally advanced rectal adenocarcinoma undergoing preoperative concurrent chemoradiotherapy (CCRT).

METHODS

In total, 203 patients with locally advanced rectal adenocarcinoma who underwent preoperative CCRT and robotic-assisted rectal surgery between May 2013 and December 2019 were enrolled. Patients were categorized into PAS and non-PAS groups based on the PAS history. The PSM caliper matching method with 1-to-3 matches was used to match PAS patients with non-PAS.

RESULTS

Of the 203 enrolled patients, 35 were PAS patients and 168 were non-PAS patients. After PSM, 32 PAS patients and 96 non-PAS patients were included for analysis. No significant between-group differences were noted in the perioperative outcomes, including median console time (165 min (PAS) vs. 175 min (non-PAS), P = 0.4542) and median operation time (275 min (PAS) vs. 290 min (non-PAS), P = 0.5943) after PSM. Postoperative recovery and overall complication rates were also similar (all P > 0.05). Moreover, the between-group differences in pathological or short-term oncological outcomes were also nonsignificant (all P > 0.05). No 30-day postoperative deaths were observed in either group.

CONCLUSION

The current results indicate that robotic-assisted surgery is safe and feasible for PAS patients with locally advanced rectal adenocarcinoma undergoing preoperative CCRT. However, future prospective randomized clinical trials are required to verify these findings.

Oncological Outcomes of Robotic-Assisted Surgery With High Dissection and Selective Ligation Technique for Sigmoid Colon and Rectal Cancer

Background: Curative resection of sigmoid colon and rectal cancer includes "high tie" of the inferior mesenteric artery (IMA). However, IMA ligation compromises blood flow to the anastomosis, which may increase the complication rate. We present preliminary experiences of operative and oncologic outcomes of patients with rectal or sigmoid colon cancer who underwent robotic surgery employing the high dissection and selective ligation technique. Methods: Over May 2013 to April 2017, 113 stage I-III rectal or sigmoid colon cancer patients underwent robotic surgery with the single-docking technique at one institution. We performed D3 lymph node dissection and low-tie ligation of the IMA (i.e., high dissection and selective ligation technique). Clinicopathological features, perioperative parameters, and postoperative outcomes were retrospectively analyzed. Overall survival (OS) and disease-free survival (DFS) were calculated using the Kaplan-Meier method. Results: Sphincter preservation rate was 96.3% in rectal cancer patients. Median number of harvested lymph nodes was 12. Apical nodes were pathologically harvested in 84 (82.4%) patients. R0 resection was performed in 108 (95.6%) patients. Overall complication rate was 17.7%; but most complications were mild and the patients recovered uneventfully. Estimated 5-year OS was 86.1% and 3-year DFS was 79.6% after median follow-up periods of 49.1 months (range, 5.3-85.3). Conclusions: High dissection of the IMA and selective ligation of the major feeding vessel to the sigmoid colon or rectum can be safely performed using da Vinci Surgical System,yielding favorable clinical, and oncologic outcomes in rectal or sigmoid colon cancer treatment.

Time interval between the completion of radiotherapy and robotic-assisted surgery among patients with stage I-III rectal cancer undergoing preoperative chemoradiotherapy

BACKGROUND

This aim of this study was to evaluate the effects of time interval between the completion of radiotherapy and robotic-assisted surgery on the outcomes among patients with rectal cancer undergoing preoperative concurrent chemoradiotherapy (CCRT).

METHODS

In total, 116 patients with stage I-III rectal cancer who underwent preoperative CCRT and robotic-assisted surgery between September 2013 and February 2019 were enrolled. Patients were categorized into two groups based on the time interval: group A (10-12 weeks) and group B (≥ 12 weeks).

RESULTS

Among the 116 enrolled patients, 98 (84.5%) had middle and lower rectal cancers. Two (1.7%) patients underwent abdominoperineal resection with a sphincter preservation rate of 98.3%. Thirty-seven (31.9%) patients had a pathologic complete response (pCR). The circumferential resection margin and distal resection margin were positive in 2 (1.7%) and 1 (0.9%) patients, respectively. Therefore, the R0 resection rate was 97.4%. A total of 24 (22.4%) patients experienced postoperative relapse and 12 (10.3%) patients died; these were slightly more common in group B than in group A (28.8% vs 15.8% and 15.3% vs 5.3%, respectively; both P > 0.05); however, this difference was nonsignificant. Three-year disease-free survival (DFS) and overall survival (OS) were 75% and 89%, respectively, among all patients. Non-significant trend of favorable 3-year DFS, 3-year OS, 3-year locoregional control rate and 3-year distant metastasis control rate were observed in group A compared with group B (all P > 0.05).

CONCLUSION

Robotic-assisted surgery after a longer interval is safe and feasible for patients with rectal cancer undergoing preoperative CCRT. The present study's results suggested that the time interval of 10-12 weeks can be considered because comparable clinical and perioperative outcomes and preferable oncological outcomes were observed for interval of this length. However, future prospective randomized clinical trials are required to verify the present finding.

Machine learning for predicting pathological complete response in patients with locally advanced rectal cancer after neoadjuvant chemoradiotherapy

For patients with locally advanced rectal cancer (LARC), achieving a pathological complete response (pCR) after neoadjuvant chemoradiotherapy (CRT) provides them with the optimal prognosis. However, no reliable prediction model is presently available. We evaluated the performance of an artificial neural network (ANN) model in pCR prediction in patients with LARC. Predictive accuracy was compared between the ANN, k-nearest neighbor (KNN), support vector machine (SVM), naïve Bayes classifier (NBC), and multiple logistic regression (MLR) models. Data from two hundred seventy patients with LARC were used to compare the efficacy of the forecasting models. We trained the model with an estimation data set and evaluated model performance with a validation data set. The ANN model significantly outperformed the KNN, SVM, NBC, and MLR models in pCR prediction. Our results revealed that the post-CRT carcinoembryonic antigen is the most influential pCR predictor, followed by intervals between CRT and surgery, chemotherapy regimens, clinical nodal stage, and clinical tumor stage. The ANN model was a more accurate pCR predictor than other conventional prediction models. The predictors of pCR can be used to identify which patients with LARC can benefit from watch-and-wait approaches.

Surgical treatment following neoadjuvant chemoradiotherapy in locally advanced rectal cancer

Colorectal cancer is a major public health problem worldwide, and locally advanced rectal cancer (LARC) is known for its poor prognosis. A multimodal treatment approach is the only method to achieve satisfactory local recurrence and survival rates in LARC. Determining which therapeutic modality for LARC has the most satisfactory influence on quality of life and disease outcome is still controversial. LARC treatment is subject to continuous advancement due to the development of new and better diagnostic tools, radiotherapy techniques, and chemotherapeutic agents. Herein, we review various therapeutic modalities for LARC from several aspects. In addition to radiotherapy techniques such as neoadjuvant chemoradiotherapy (NCRT), we discuss the progress of chemotherapy, appropriate time interval between NCRT and surgery, relationship between tumor location and NCRT efficacy/safety, wait-and-watch policy, and predictors of treatment response following NCRT. Because of the controversies and unanswered questions regarding NCRT treatments for LARC, additional investigations are required to determine which therapeutic approach is the most feasible for LARC patients.

Dose-time fractionation schedules of preoperative radiotherapy and timing to surgery for rectal cancer

Chemoradiotherapy (CRT) is extensively used prior to surgery for rectal cancer to provide significantly better local control, but the radiotherapy (RT), as the other component of CRT, has been subject to less interest than the drug component in recent years. With considerable developments in RT, the use of advanced techniques, such as intensity-modulated radiotherapy (IMRT) in rectal cancer, is garnering more attention nowadays. The radiation dose can be better conformed to the target volumes with possibilities for synchronous integrated boost without increased complications in normal tissue. Hopefully, both local recurrence and toxicities can be further reduced. Although those seem to be of interest, many issues remain unresolved. There is no international consensus regarding the radiation schedule for preoperative RT for rectal cancer. Moreover, an enormous disparity exists regarding the RT delivery. With the advent of IMRT, variations will likely increase. Moreover, time to surgery is also quite variable, as it depends upon the indication for RT/CRT in the clinical practices. In this review, we discuss the options and problems related to both the dose-time fractionation schedule and time to surgery; furthermore, it addresses the research questions that need answering in the future.

Predictive Value of FOLFOX-Based Regimen, Long Interval, Hemoglobin Levels and Clinical Negative Nodal Status, and Postchemoradiotherapy CEA Levels for Pathological Complete Response in Patients with Locally Advanced Rectal Cancer after Neoadjuvant Chemoradiotherapy

We aimed to identify predictors of a pathological complete response (pCR) in patients with locally advanced rectal cancer (LARC) following a multimodality therapy. We retrospectively reviewed 236 patients with LARC treated with neoadjuvant chemoradiotherapy (CRT) followed by radical resection from January 2011 to December 2017. Patients were administered CRT, which comprised radiotherapy and chemotherapy with an oxaliplatin plus 5-fluorouracil- or fluoropyrimidine-based regimen. Clinical factors were correlated with treatment response. The multivariate logistic regression revealed that a negative nodal stage (odds ratio (OR) = 3.2, P=0.0135), a high hemoglobin level (>10 g/dL) during neoadjuvant CRT (OR = 3.067, P=0.0125), an oxaliplatin-containing neoadjuvant CRT (OR = 5.385, P=0.0044), a long interval (>8 weeks) between radiotherapy and surgery (OR = 1.135, P=0.0469), and a post-CRT CEA ≤2 ng/mL (OR = 2.891, P=0.0233) were the independent predictors of increased pCR rates. The prediction nomogram was developed according to the above independent variables. The concordance index was 0.74, and the calibration curve showed good agreement. In summary, negative nodal stages, high hemoglobin levels during treatment, oxaliplatin-containing neoadjuvant therapy, a long radiotherapy-surgery interval (>8 weeks), and post-CRT CEA levels ≤2 ng/mL were favorable predictors of a pCR. This prediction nomogram might be crucial for patients with LARC undergoing a multimodality therapy.

Chemoradiotherapy with Concurrent Regional Arterial Chemotherapy for Locally Bulky Unresectable Rectal Cancer: A Case Series

INTRODUCTION

We evaluated the feasibility and efficacy of chemoradiotherapy with concurrent regional arterial chemotherapy (CRT/RAC) for locally bulky unresectable rectal cancer (LBURC).

CASE PRESENTATION

We retrospectively reviewed 9 patients with LBURC who received CRT/RAC between January 2012 and December 2018. The regimen consisted of chemoradiotherapy and 3 cycles of regional arterial chemotherapy. Surgery was performed 6 weeks after completion of radiotherapy. The median longest tumor diameter was 10 cm (range 8.2-13.6). Grade 3 toxicity and postoperative complications occurred in 3 and 4 patients, respectively. All patients showed partial response according to the Response Evaluation Criteria in Solid Tumors (RECIST). One patient refused the operation after completion of the scheduled regimen but then had a bowel obstruction and had to undergo urgent surgery. Of the 8 patients who underwent scheduled surgery, all had R0 resection without multivisceral resection; 3 achieved pathological complete response and 5 exhibited good tumor regression. The median follow-up period was 35 months (range 9-63). Recurrences occurred in 3 of 9 patients (pelvic relapses in 2 and lung in 1).

CONCLUSION

CRT/RAC appeared to be beneficial to LBURC, as it achieves remarkable rates of R0 resection, good tumor regression, and pathologic complete response. These preliminary results have to be confirmed in larger cohorts of patients.

The survival benefit of intensified full-dose XELOX chemotherapy concomitant to radiotherapy and then resting-period consolidation chemotherapy in locally advanced rectal cancer

Purpose: To evaluate the effect of an intensified capecitabine and oxaliplatin (XELOX) chemoradiation treatment followed by one cycle of consolidation chemotherapy before surgery in locally advanced rectal cancer (LARC).

Methods and Materials: Patients with histologically confirmed, newly diagnosed, locally advanced rectal adenocarcinoma (cT3-T4 and/or cN+) were enrolled. All patients received 3-dimensional conformal radiotherapy (3D-CRT) or intensity-modulated radiotherapy (IMRT) with a dose 50.4Gy in 25 fraction, with two cycles of concurrent XELOX chemotherapy. Thereafter, another cycle of consolidation chemotherapy with XELOX/FLOFOX was administered during the resting period after completion of concurrent chemoradiation (CRT). Tumor response, toxicities, surgical complications, and long-term clinical outcomes were recorded.

Results: From January 2011 to December 2013, a total of 96 patients were enrolled in the study. All patients completed the treatment plan of concurrent chemoradiation and consolidate chemotherapy. During concurrent chemoradiation, the incidence of grade 3/4 toxicities was leucopenia (2.1%), thrombocytopenia (4.2%), diarrhea (6.3%). 18 patients (18.8%) developed surgical complications. Pathologic complete response (pCR) was achieved in 20 (20.8%) patients. Tumor down-staging occurred in 69 (71.9%) patients and down-staging of nodes occurred in 47 (49.0%) patients. Of these 96 patients, 5-year local recurrence-free survival, metastasis-free survival, disease-free survival and overall survival rates was 98.9%, 84.7%, 83.7% and 82.1%, respectively, with a median follow-up of 4.24years.

Conclusions: The intensified treatment paradigm of XELOX concurrent chemoradiation followed by one cycle of consolidation chemotherapy was well tolerated in our cohort and provided a promising long-term oncologic outcome, which warranted further investigation in a randomize trails.

Comparison of efficacy and safety of preoperative Chemoradiotherapy in locally advanced upper and middle/lower rectal cancer

BACKGROUND

We aimed to explore the efficacy and safety profile of preoperative neoadjuvant chemoradiation (NACRT) in locally advanced rectal cancer (LARC) in upper rectum versus middle/lower rectum.

METHODS

The study included 173 patients with stage II or III (T2-4b, N0-2b) LARC who underwent NACRT followed by total mesorectal excision (TME) between January 2011 and October 2016. Cox regression, log-rank test, and Kaplan-Meier curves were calculated.

RESULTS

Among the 173 patients, 58 had lesions in the upper rectum and 115 patients had lesions in middle/lower rectum. In a median follow-up of 35 months (range, 6-73 months), the 5-year disease-free survival (DFS) and overall survival (OS) were 84% and 88% for the patients with upper rectal cancer and 77% and 68% for those with middle/lower rectal cancer (P = 0.251 and P = 0.058, respectively). The 5-year DFS (P = 0.012) and OS (P = 0.003) were better in the NACRT responders [tumor regression grade (TRG) 0 or 1] compared with nonresponders (TRG 2 or 3). The independent prognostic factor of favorable response to NACRT was the FOLFOX regimen (P = 0.004).

CONCLUSIONS

Patients with LARC in the upper rectum who underwent NACRT followed by TME had similar DFS and a trend toward longer OS, compared with those who had middle/lower rectal lesions. Furthermore, FOLFOX may yield superior results than fluoropyrimidine based regimen during NACRT. NACRT might be an alternative option for patients with LARC in the upper rectum as it has a favorable pathological complete response rate and comparable clinical outcomes when compared with patients with LARC in middle/lower rectum.

Organ Preservation in Rectal Cancer After Chemoradiation: Should We Extend the Observation Period in Patients with a Clinical Near-Complete Response?

BACKGROUND

To assess whether extending the observation period in patients with a near clinical complete response (near cCR) after chemoradiation (CRT) leads to an impaired oncological outcome.

METHODS

Patients who had a clinical complete response (cCR) 8-10 weeks after CRT restaging with magnetic resonance imaging and endoscopy were offered a watch-and-wait strategy (W&W1), while patients with a near cCR were offered to undergo local excision or a second restaging 6-12 weeks later. Patients who achieved a cCR at the second restaging were also offered a watch-and-wait strategy (W&W2).

RESULTS

Overall, 102 patients with a cCR at the first restaging immediately entered the W&W1, while the remaining 68 patients had a near cCR: 19 patients underwent transanal endoscopic microsurgery and 49 patients opted for a second restaging. Additionally, 44/49 (90%) patients showed a cCR at the second restaging and entered the W&W2. Patients in the W&W1 group had a 2-year local regrowth-free rate (LRFR) of 84% and 2-year overall survival (OS) of 99%, while patients in the W&W2 group had a 2-year LRFR of 73% and OS of 98% (p > 0.05). Multivariable Cox regression analyses showed that late inclusion was not a significant predictive factor for higher risk of LR or lower non-regrowth disease-free survival.

CONCLUSIONS

Overall, 90% of patients with a near cCR 8-10 weeks after CRT will proceed to a cCR 6-12 weeks later; therefore, it seems logical to extend the observation period rather than to proceed to surgery. Although there is a non-significant increase in local regrowth rate in these patients, it does not seem to impact the oncological outcome.

Relationship Between Expression of Proteins ERCC1, ERCC2, and XRCC1 and Clinical Outcomes in Patients with Rectal Cancer Treated with FOLFOX-Based Preoperative Chemoradiotherapy

BACKGROUND

Platinum resistance enhances DNA damage repair through nucleotide excision repair mechanisms involving the excision repair cross-complementing group 1 (ERCC1), X-ray cross-complementing group 1 (XRCC1), and excision repair cross-complementing group 2 (ERCC2). We evaluated the correlation between the expression of these three DNA repair genes and clinical outcomes in patients with rectal cancer receiving FOLFOX-based preoperative chemoradiotherapy (CRT).

METHODS

Using immunohistochemistry, we examined the expression of ERCC1, ERCC2, and XRCC1 in pre-CRT cancer tissues from 86 patients with rectal cancer who had undergone curative resection and preoperative CRT with FOLFOX-4 to identify potential predictors of clinical outcomes.

RESULTS

Following CRT, 57 and 29 patients were classified as responders (pathological tumor regression grade TRG 0 and TRG 1) and poor responders (TRG 2 and TRG 3), respectively. The multivariate analysis revealed that ERCC1 overexpression was correlated with a poor CRT response [p < 0.0001; odds ratio (OR), 9.397; 95% confidence interval (CI) 2.721-32.457]. Furthermore, a poor response to CRT (pathological TRG of 2-3) (p = 0.18; OR 5.685; 95% CI 1.349-23.954) and abnormal pre-CRT serum carcinoembryonic antigen levels (>5 ng/mL) (p = 0.03; OR 6.288; 95% CI 1.198-33.006) were independent predictors of postoperative relapse. By contrast, ERCC2 and XRCC1 expression did not play predictive roles in the analyzed patients.

CONCLUSIONS

ERCC1 overexpression is associated with a poor preoperative CRT response in patients with rectal cancer receiving FOLFOX-based preoperative CRT. ERCC1 is a potential biomarker for identifying patients who can benefit from customized treatment programs.

Neoadjuvant FOLFOX chemotherapy combined with radiotherapy followed by radical resection in patients with locally advanced colon cancer

BACKGROUND

Patients with locally advanced colon cancer (LACC) have a relatively poor prognosis despite radical resection and adjuvant chemotherapy. This study investigated the treatment efficacy and toxicity of neoadjuvant chemoradiotherapy in patients with LACC.

METHODS

We retrospectively reviewed 36 patients with LACC preoperatively treated with chemotherapy and radiotherapy. Patients were administered chemoradiotherapy, which comprised radiotherapy and neoadjuvant chemotherapy involving a 5-fluorouracil, leucovorin, and oxaliplatin regimen every 2 weeks.

RESULTS

Median age was 64 years (45-86 years) and median follow-up period was 23.5 months (5.0-49.1 months). Seven (19.4%) patients developed grade 3 or 4 adverse events during neoadjuvant concurrent chemoradiotherapy. Pathologic responses were not evaluated in two patients who did not undergo radical resection. Of the 34 patients who underwent surgery, nine (26.4%) achieved a pathologic complete response (pCR). The 2-year estimated overall survival and disease-free survival rates were 88.7% and 73.6%, respectively.

CONCLUSIONS

Our results demonstrated that neoadjuvant chemoradiotherapy is feasible and safe. A prominent pCR rate with an acceptable toxicity profile suggests that the multimodality therapy might be a treatment option for patients with LACC.

A retrospective comparison of outcome and toxicity of preoperative image-guided intensity-modulated radiotherapy versus conventional pelvic radiotherapy for locally advanced rectal carcinoma

The aim of the study was to compare clinical outcomes and toxicity between 3D conformal radiotherapy (3DCRT) and image-guided intensity-modulated radiotherapy (IG-IMRT) administered through helical tomotherapy in locally advanced rectal cancer (LARC) patients receiving preoperative chemoradiotherapy. We reviewed 144 patients with Stage II-III rectal cancer receiving preoperative fluoropyrimidine-based chemoradiotherapy followed by radical resection. Tumor responses following chemoradiotherapy were evaluated using the Dworak tumor regression grade (TRG). Of the 144 patients, 45 received IG-IMRT and 99 received 3DCRT. A significant reduction in Grade 3 or 4 acute gastrointestinal toxicity (IG-IMRT, 6.7%; 3DCRT, 15.1%; P = 0.039) was observed by IG-IMRT. The pathologic complete response (pCR) rate did not differ between the IG-IMRT and the 3DCRT group (17.8% vs 15.1%, P = 0.52). Patients in the IG-IMRT group had the trend of favorable tumor regressions (TRG 3 or 4) compared with those in the 3DCRT group (66.7% vs 43.5%, P = 0.071). The median follow-up was 53 months (range, 18-95 months) in the 3DCRT group and 43 months (range, 17-69 months) in the IG-IMRT group. Four-year overall, disease-free, and local failure-free survival rates of the IG-IMRT and 3DCRT groups were 81.6% and 67.9% (P = 0.12), 53.8% and 51.8% (P = 0.51), and 88% and 75.1% (P = 0.031), respectively. LARC patients treated with preoperative IG-IMRT achieved lower acute gastrointestinal adverse effects and a higher local control rate than those treated with 3DCRT, but there was no prominent difference in distant metastasis rate and overall survival between two treatment modalities.