Randomized phase II study of neoadjuvant combined-modality chemoradiation for distal rectal cancer: Radiation Therapy Oncology Group Trial 0012

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of Controlled Trials (CENTRAL), and Web of Science Core Collection electronic databases and ClinicalTrials.gov for unpublished studies were searched from inception to March 2, 2024.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

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.

Radiotherapy in the preoperative neoadjuvant treatment of locally advanced rectal cancer

Radiotherapy and chemotherapy are effective treatments for patients with locally advanced rectal cancer (LARC) and can significantly improve the likelihood of R0 resection. Radiotherapy can be used as a local treatment to reduce the size of the tumor, improve the success rate of surgery and reduce the residual cancer cells after surgery. Early chemotherapy can also downgrade the tumor and eliminate micrometastases throughout the body, reducing the risk of recurrence and metastasis. The advent of neoadjuvant concurrent radiotherapy (nCRT) and total neoadjuvant treatment (TNT) has brought substantial clinical benefits to patients with LARC. Even so, given increasing demand for organ preservation and quality of life and the disease becoming increasingly younger in its incidence profile, there is a need to further explore new neoadjuvant treatment options to further improve tumor remission rates and provide other opportunities for patients to choose watch-and-wait (W&W) strategies that avoid surgery. Targeted drugs and immunologic agents (ICIs) have shown good efficacy in patients with advanced rectal cancer but have not been commonly used in neoadjuvant therapy for patients with LARC. In this paper, we review several aspects of neoadjuvant therapy, including radiation therapy and chemotherapy drugs, immune drugs and targeted drugs used in combination with neoadjuvant therapy, with the aim of providing direction and thoughtful perspectives for LARC clinical treatment and research trials.

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.

Optimal waiting period to surgical treatment after neoadjuvant chemoradiotherapy for locally advanced rectum cancer: a retrospective observational study

BACKGROUND

The optimal waiting period after neoadjuvant treatment in patients with locally advanced rectal cancers is still controversial. The literature has different results regarding the effect of waiting periods on clinical and oncological outcomes. We aimed to investigate the effects of these different waiting periods on clinical, pathological, and oncological outcomes.

METHODS

Between January 2014 and December 2018, a total of 139 consecutive patients with locally advanced rectal adenocarcinoma, who were treated in the Department of General Surgery at the Marmara University Pendik Training and Research Hospital, were enrolled in the study. The patients were split into three groups according to waiting time for surgery after neoadjuvant treatment: group 1 (n = 51) included patients that have 7 weeks and less (≤ 7 weeks) time interval, group 2 (n = 45) 8 to 10 weeks (8-10 weeks), group 3 (n = 43) 11 weeks and above (11 weeks ≤). Their database records, which were entered prospectively, were analyzed retrospectively.

RESULTS

There were 83 (59.7%) males and 56 (40.3%) females. The median age was 60 years, and there was no statistical difference between the groups regarding age, gender, BMI, ASA score, ECOG performance score, tumor location, and preoperative CEA values. Also, we found no significant differences regarding operation times, intraoperative bleeding, length of hospital stay, and postoperative complications. According to the Clavien-Dindo (CD) classification, severe early postoperative complications (CD 3 and above) were observed in 9 patients. The complete pathological response (pCR, ypT0N0) was observed in 21 (15.1%) patients. The groups had no significant difference regarding 3-year disease-free and 3-year overall survival (p = 0.3, p = 0.8, respectively). Local recurrence was observed in 12 of 139 (8.6%) patients and distant metastases occurred in 30 of 139 (21.5%) patients during the follow-up period. There was no significant difference between the groups in terms of both local recurrence and distant metastasis (p = 0.98, p = 0.43, respectively).

CONCLUSION

The optimal time for postoperative complications and sphincter-preserving surgery in patients with locally advanced rectal cancer is 8-10 weeks. The different waiting periods do not affect disease-free and overall survival. While long-term waiting time does not make a difference in pathological complete response rates, it negatively affects the TME quality rate.

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.

Hyperfractionation versus Conventional Fractionation of Preoperative Intensity-Modulated Radiotherapy with Oral Capecitabine in Locally Advanced Mid-Low Rectal Cancer: A Propensity Score Matching Study

Purpose

In theory, the hyperfractionated radiotherapy can enhance biological effect dose against tumor and alleviate normal tissue toxicity. This study is to assess the efficacy and safety of preoperative hyperfractionated intensity-modulated radiotherapy (IMRT) with oral capecitabine in patients with locally advanced rectal cancer (LARC).

Methods

We retrospectively screened patients with LARC from January 2015 to June 2016. Patients that received hyperfractionated IMRT or conventional fractionated IMRT were eligible in the hyperfractionation (HF) group or conventional fractionation (CF) group, respectively. The primary outcome was the complete response rate. Secondary outcomes included toxicity, postoperative complications, anus-reservation operation rate, local recurrence and distant metastases rate, overall survival (OS), cancer-specific survival (CSS), and disease-free survival (DFS).

Results

335 patients were included in the analysis. The complete response rate for the hyperfractionated and conventional fractionated IMRT was 20.41% vs. 23.47% (P = 0.583). The anus-reservation operation rate was 68.37% vs. 65.31% (P = 0.649). There were no cases of grade 4 toxicity during radiotherapy; the rate of grade 3 toxicity and postoperative complications was both comparable between groups. However, in the CF group, more patients had a second operation due to complications (0.0% vs. 5.68%, P = 0.011). The cumulative local regional recurrence and distant metastases rates of the HF group and CF group were 5.10% vs. 9.18% (P = 0.267) and 22.45% vs. 24.49% (P = 0.736), respectively. The 5-year OS, CSS, and DFS in the HF group and CF group were 86.45% vs. 73.30% (P = 0.503), 87.34% vs. 75.23% (P = 0.634), and 70.80% vs. 68.11% (P = 0.891), respectively.

Conclusions

The preoperative hyperfractionated IMRT with oral capecitabine, with an acceptable toxicity and favorable response and survival, could reduce the rate of secondary surgery.

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.

Current evidence regarding the role of adjuvant chemotherapy in rectal cancer patients with pathologic complete response after neoadjuvant chemoradiotherapy: a systematic review and meta-analysis

PURPOSE

The aim of this meta-analysis was to investigate the role of adjuvant chemotherapy (AC) in rectal cancer patients with pathologic complete response (pCR) after neoadjuvant chemoradiotherapy (nCRT) and curative resection.

METHODS

This study was completed in accordance to the PRISMA guidelines and the Cochrane Handbook for Systematic Reviews of Interventions. The electronic scholar databases (Medline, Web of Science, Scopus) were screened for eligible articles. The level of evidence (LoE) was assessed using the GRADE methodology.

RESULTS

Overall, 23 non-randomized studies and 17,406 patients were included in the present meta-analysis. Pooled comparisons confirmed that AC improved overall survival (HR: 0.68, p=0.0003), but not disease-free (p=0.22) and recurrence-free survival (p=0.39). However, the LoE for all outcomes was characterized as "very low," due to the absence of RCTs.

CONCLUSIONS

Considering the study limitations and the lack of randomized studies, further high-quality RCTs are required to confirm the findings of our study.

Adding Adjuvants to Fluoropyrimidine-based Neoadjuvant Chemoradiotherapy for Locally Advanced Rectal Cancer: An Option Worthy of Serious Consideration

The application of fluoropyrimidine-based neoadjuvant chemoradiotherapy (Fu-nCRT) of locally advanced rectal cancer (LARC) has become a common therapeutic regimen. In order to improve the efficacy and enable more patients to benefit from this treatment, an accumulation of studies have been carried out on the auxiliary use of other drugs with Fu-nCRT. However, due to specific challenges and the potential opportunities that coexist in this field, a more reasonable approach to the mode of treatment remains to be explored. In this review, we have summarized the results of the studies on the combination of Fu-nCRT with cytotoxic drugs, anti-tumor angiogenesis, and anti-EGFR agents, as well as the status of the application of immune checkpoint inhibitors in the neoadjuvant therapy of LARC patients.

Feasibility and Safety of Laparoscopic Radical Colectomy for T4b Colon Cancer at a University Hospital in Vietnam

BACKGROUND

The choice of optimal treatment strategies for T4b colon cancers has still been discussed, particularly the initiation of neoadjuvant therapy or surgery. We conducted this study to evaluate the safety and feasibility of laparoscopic multivisceral resection for T4b colon cancers.

METHODS

We used the retrospective design to include all 43 patients with T4b colon cancer at a university hospital in Vietnam from March 2017 to March 2019. All patients were followed 30 days after the surgery, and information about the day of the first flatus, length of hospital stay, iatrogenic complications, postoperative morbidity, mortality, and adjuvant chemotherapy was collected.

RESULTS

The mean operating time was 187 minutes (ranging from 80 to 310), the mean blood loss was 64.3 ml (5-200), and the conversion rate was 2.3%. The mean number of lymph nodes harvested was 15.5 (SD = 8.06), and 33 patients (76.7%) had at least 12 lymph nodes harvested. A total of 21 patients (48.8%) had lymph node metastases with a mean number of lymph node metastases of 1.89 (SD = 3.4). The radial resection margin was R0 in all 43 patients (100%). The median time until the first flatus and hospital stay were 3 days (2-5) and 7.1 (6-11) days, respectively. There was no mortality at 30 days postoperatively, and one patient had iatrogenic complication (2.3%).

CONCLUSION

Laparoscopic radical colectomy was feasible and safe for patients with T4b colon cancer except those requiring major and complicated reconstruction.

Recent advances in (chemo-)radiation therapy for rectal cancer: a comprehensive review

The role of radiation therapy in the treatment of (colo)-rectal cancer has changed dramatically over the past decades. Introduced with the aim of reducing the high rates of local recurrences after conventional surgery, major developments in imaging, surgical technique, systemic therapy and radiation delivery have now created a much more complex environment leading to a more personalized approach. Functional aspects including reduction of acute or late treatment-related side effects, sphincter or even organ-preservation and the unsolved problem of still high distant failure rates have become more important while local recurrence rates can be kept low in the vast majority of patients. This review summarizes the actual role of radiation therapy in different subgroups of patients with rectal cancer, including the current standard approach in different subgroups as well as recent developments focusing on neoadjuvant treatment intensification and/or non-operative treatment approaches aiming at organ-preservation.

Multicenter, Randomized, Phase III Trial of Neoadjuvant Chemoradiation With Capecitabine and Irinotecan Guided by UGT1A1 Status in Patients With Locally Advanced Rectal Cancer

Differentiating the irinotecan dose on the basis of the uridine diphosphate glucuronosyltransferase 1A1 (UGT1A1) genotype improves the pathologic complete response (pCR) rate. In this study, we further investigated preoperative irinotecan combined with capecitabine-based chemoradiotherapy for locally advanced rectal cancer.

Even a partial pathological response is associated with lower relapse rates in patients with operable rectal cancer undergoing neoadjuvant chemotherapy

BACKGROUND

Neoadjuvant chemotherapy to treat locally advanced rectal cancer is an effective therapeutic strategy for the prevention of local recurrence and distant organ metastasis after surgery.

OBJECTIVES

To assess the prognostic significance of histopathological tumor response in rectal cancer patients undergoing neoadjuvant chemotherapy.

METHODS

This study included patients with operable rectal cancer who received neoadjuvant chemotherapy using the FOLFOX regimen (5-fluorouracil, l-leucovorin, and oxaliplatin) in a hospital between February 2012 and November 2017. The main outcome measure was disease-free survival with respect to histopathological response to neoadjuvant chemotherapy in resected specimens.

RESULTS

The median follow-up was 32 months. Of 48 patients treated with neoadjuvant FOLFOX, 24 (50%) were classified as responders, which included two patients with pathological complete response and 22 patients with partial response. The remaining 24 patients (50%) were classified as nonresponders. Responders had a significantly better 3-year disease-free survival than nonresponders (86% vs. 62%, p = .02).

CONCLUSIONS

Patients whose surgical specimens show a pathological complete response or partial response have good oncologic outcomes.

The impact of sarcopenia on pathologic complete response following neoadjuvant chemoradiation in rectal cancer

PURPOSE

The role of sarcopenia in pathologic complete response (pCR) following neoadjuvant chemoradiotherapy (nCRT) in non-metastatic locally advanced rectal cancer is currently unknown. The present study investigates the association between sarcopenia and post-nCRT pCR.

METHODS

The data of patients operated on following nCRT between January 2013 and January 2020 were collected retrospectively. Sarcopenia was diagnosed based on the calculation of the skeletal muscle index (SMI) from computed tomography carried out at the time of the initial diagnosis. A statistical analysis was then conducted for predictors of pCR.

RESULTS

The study included 61 patients with an average age of 57.3 years, 28 of whom formed the non-sarcopenic group (NSG) and 33 the sarcopenic group (SG). Of the patients, 32.7% were at clinical stage 2, and 67.3% were at clinical stage 3. Pathologic data following a mesorectal excision revealed a pCR rate of 21.4% in the NSG compared with 3% in the SG, which was a statistically significant difference (p = 0.025). The TNM downstaging rate was higher in the NSG than in the SG, although the difference was not statistically significant (50% vs. 33.3%, p = 0.28). A univariate analysis revealed the factors affecting pCR to be non-sarcopenia (p = 0.025), age < 61 years (p = 0.004), interval to surgery ≥ 8 weeks (p = 0.029), and serum CEA < 2.5 ng/ml (p = 0.035).

CONCLUSION

Sarcopenia was found to be a negative marker of pCR following nCRT in non-metastatic locally advanced rectal cancer.

Retrospective study of preoperative chemoradiotherapy with capecitabine versus capecitabine plus oxaliplatin for locally advanced rectal cancer

This study aimed to evaluate whether the addition of oxaliplatin to a neoadjuvant chemoradiotherapy (CRT) regimen could improve survival benefit in locally advanced rectal cancer (LARC) patients. We retrospectively analysed 73 LARC patients (cT2-4 and/or cN1-2) who received preoperative CRT with capecitabine followed by surgery (arm A, 43 patients) or capecitabine plus oxaliplatin followed by surgery (arm B, 30 patients). The main endpoints of the study were pathologic complete response (pCR) rate, overall survival (OS) and disease-free survival (DFS). The secondary endpoints included the sphincter preservation rate and safety. The pCR for arms A and B were 28% and 17% (P = 0.267). In arms A and B, the mean OS was 84.287 months (95% CI 68.413-100.160) and 106.333 months (95% CI 99.281-113.386) (P = 0.185); the mean DFS was 72.812 months (95% CI 56.271-89.353) and 95.073 months (95% CI 83.392-106.754) (P = 0.310); and the sphincter preservation rates were 72% and 67%, respectively (P = 0.619). The incidence of grade 3 toxicity was much higher in arm B than in arm A (57% vs. 21%, P = 0.002). Adding oxaliplatin to a preoperative CRT regimen for LARC did not improve the survival benefits of patients or increase toxicity.

Neoadjuvant Radiotherapy Dose Escalation in Locally Advanced Rectal Cancer: a Systematic Review and Meta-analysis of Modern Treatment Approaches and Outcomes

AIMS

Improving pathological complete response (pCR) rates after neoadjuvant chemoradiotherapy for locally advanced rectal cancer may facilitate surgery-sparing treatment paradigms. Radiotherapy boost has been linked to higher rates of pCR; however, outcomes in moderately escalated inverse-planning studies have not been systematically evaluated. We therefore carried out a systematic review and meta-analysis of radiation dose-escalation studies in the context of neoadjuvant therapy for locally advanced rectal cancer.

MATERIALS AND METHODS

A systematic search of Pubmed, EMBASE and Cochrane databases for synonyms of 'rectal cancer', 'radiotherapy' and 'boost' was carried out. Studies were screened for radiotherapy prescription >54 Gy. Prespecified quality assessment was carried out for meta-analysis inclusion suitability. Pooled estimates of pCR, acute toxicity (grade ≥3) and R0 resection rates were determined with random-effects restricted maximum-likelihood estimation. Heterogeneity was assessed with Higgins I² and Cochran Q statistic. Subset analysis examined outcomes in modern inverse-planning studies. Meta-regression with permutation correction was carried out for each outcome against radiation dose, radiotherapy technique, boost technique, chemotherapy intensification and other patient- and treatment-related cofactors.

RESULTS

Forty-nine primary and three follow-up publications were included in the systematic review. Pooled estimates of pCR, toxicity and R0 resection across 37 eligible publications (n = 1817 patients) were 24.1% (95% confidence interval 21.2-27.4%), 11.2% (95% confidence interval 7.2-17.0%) and 90.7% (95% confidence interval 87.9-93.8%). Within inverse-planning studies (17 publications, n = 959 patients), these rates were 25.7% (95% confidence interval 21.0-31.1%), 9.8% (95% confidence interval 4.6-19.7%) and 95.3% (95% confidence interval 91.6-97.4%). Regression analysis did not identify any significant predictor of pCR (P > 0.05).

CONCLUSIONS

Radiotherapy dose escalation above 54 Gy is associated with high rates of pCR and does not seem to increase the risk of acute grade ≥3 toxicity events. pCR rates approaching 25% may be achievable utilising moderate escalation (54-60 Gy) with modern inverse-planning techniques; however, a clear dose-response relationship was not identified in regression analysis and additional evidence is awaited given the prevalence of heterogenous single-arm studies to date.

Pathological Complete Response Following Different Neoadjuvant Treatment Strategies for Locally Advanced Rectal Cancer: A Systematic Review and Meta-analysis

Background

Pathological complete response (pCR) following neoadjuvant treatment for locally advanced rectal cancer (LARC) is associated with better survival, less local recurrence, and less distant failure. Furthermore, pCR indicates that the rectum may have been preserved. This meta-analysis gives an overview of available neoadjuvant treatment strategies for LARC and analyzes how these perform in achieving pCR as compared with the standard of care.

Methods

Pubmed, Embase, and Cochrane Central bibliographic databases were searched. Randomized controlled trials in which patients received neoadjuvant treatment for MRI-staged nonmetastatic resectable LARC were included. The primary outcome was pCR, defined as ypT0N0. A meta-analysis of studies comparing an intervention with standard fluoropyrimidine-based chemoradiation (CRT) was performed.

Results

Of the 17 articles included in the systematic review, 11 were used for the meta-analysis. Addition of oxaliplatin to fluoropyrimidine-based CRT resulted in significantly more pCR compared with fluoropyrimidine-based CRT only (OR 1.46), but at the expense of more ≥ grade 3 toxicity. Other treatment strategies, including consolidation/induction chemotherapy and short-course radiotherapy (SCRT), did not improve pCR rates. None of the included trials reported a benefit in local control or OS. Five-year DFS was significantly worse after SCRT-delay compared with CRT (59% vs. 75.1%, HR 1.93).

Conclusions

All included trials fail to deliver high-level evidence to show an improvement in pCR compared with standard fluoropyrimidine-based CRT. The addition of oxaliplatin might result in more pCR but at the expense of more toxicity. Furthermore, this benefit does not translate into less local recurrence or improved survival.

Electronic supplementary material

The online version of this article (10.1245/s10434-020-08615-2) contains supplementary material, which is available to authorized users.

The Impact of Chemotherapy Completion on the Efficacy of Irinotecan in the Preoperative Chemoradiotherapy of Locally Advanced Rectal Cancer: An Expanded Analysis of the CinClare Phase III Trial

BACKGROUND

This study explored the impact of chemotherapy completion on irinotecan efficacy in preoperative chemoradiotherapy in patients with locally advanced rectal cancer.

PATIENTS AND METHODS

Patients with locally advanced rectal cancer (T3/4 and/or LN+) receiving neoadjuvant chemoradiotherapy were enrolled. All received preoperative pelvic radiotherapy concurrently with capecitabine and irinotecan, followed by a course of XELIRI and surgery. Patients were divided into low- and high-completion groups based on their cycles of concurrent irinotecan (1-3 or 4-5). Tumor response was compared. Significant risk factors for low completion were investigated by logistic regression modeling then a predictive nomogram was built.

RESULTS

Overall, 371 patients were enrolled, with 102 patients from CinClare phase III trial (NCT02605265). Proportions of patients with low and high completion were 38.8% and 61.2%, respectively. In the general population, the complete tumor response rates (combining sustained clinical complete response and pathologic complete response) were 21.5% and 33.6% in the low- and high-completion groups, respectively (P = .02), which were 24.2% versus 43.5% in the CinClare group (P = .08). The pathologic complete response rates were 19.4% and 26.1%, respectively (P = .19). A predictive nomogram was established and 3 different risk groups (low, intermediate, and high risk) were identified, with high completion rates of 29.2%, 50.0%, and 68.9%, respectively (P < .0001).

CONCLUSION

Our analysis suggested higher completion of concurrent irinotecan was associated with better tumor response for patients with locally advanced rectal cancer with UGT1A1∗1∗1 or UGT1A1∗1∗28 phenotypes in the neoadjuvant setting, and at least 4 cycles was recommended.

Long-course neoadjuvant chemoradiotherapy with versus without a concomitant boost in locally advanced rectal cancer: a randomized, multicenter, phase II trial (FDRT-002)

Background

This study was designed to explore whether an intensified chemoradiotherapy (CRT) led to a better clinical outcome in locally advanced rectal cancer.

Methods

Patients with stage II/III rectal cancer were randomly allocated to receive either pelvic intensity-modulated radiation therapy (IMRT) of 50 Gy/25Fx concurrently with capecitabine and oxaliplatin (Arm A), or pelvic radiation of 50 Gy/25Fx with a concomitant boost of 5 Gy to the primary lesion, followed by a cycle of XELOX 2 weeks after the end of CRT (Arm B). All patients were planned to receive a definitive operation 8 weeks after the completion of CRT and a total of six perioperative chemotherapy cycles of capecitabine and oxaliplatin regardless of pathological result. Pathological complete response (ypCR) was the primary endpoint.

Results

From February 2010 to December 2011, 120 patients from three centers were enrolled in this study. Ninety-five percent patients completed a full-dose chemoradiotherapy as planning. Then 53 and 57 patients received a radical surgery, and 8 and 14 cases were confirmed as ypCR in two groups (P = 0.157). The other 10 patients failed to receive a definitive resection because of unresectable disease. Similar toxicities were observed between two groups and more incision healing delay were found in Arm B (3 vs.13, P = 0.011). No statistical differences were observed in local-regional control (P = 0.856), disease-free survival (P = 0.349) and overall survival (P = 0.553). Mesorectal fascia (MRF) involvement was an independent prognostic factor for survival in multivariate analysis.

Conclusions

A concomitant boost to oxalipatin-combined preoperative chemoradiotherapy demonstrated a slightly higher pCR rate but delayed incision healing after surgery. The impact of MRF involvement on survival merits further investigations.

Trial registration

NCT01064999 (ClinicalTrials.gov).

Neoadjuvant volumetric modulated arc radiochemotherapy with a simultaneous integrated boost technique compared to standard chemoradiation for locally advanced rectal cancer

Background/aim

The present study aimed to examine whether the combination of neoadjuvant volumetric modulated arc radiotherapy (VMAT) using simultaneous integrated boost (SIB-VMAT) techniques and chemotherapy with capecitabine is associated with better clinical and dosimetric outcomes compared to the standard treatment.

Materials and methods

The study included 59 patients with cT2–T4 rectal cancer. In the standard arm, patients (n = 37) were treated preoperatively with image-guided VMAT plus capecitabine. In the SIB arm, patients (n = 22) were treated with the SIB-VMAT technique plus capecitabine. All patients underwent radical surgical resection after neoadjuvant radiochemotherapy.

Results

In the standard arm, cT0N0 was reached in 12 patients (32.4%), primary tumor clinical downstaging was observed in 22 patients (59.5%), and disease stability was achieved in 3 patients (8.1%). In the SIB arm, cT0N0 was reached in 15 patients (68.2%), primary tumor clinical downstaging was observed in 6 patients (27.3%), and disease stability was achieved in 1 patient (4.5%) (P = 0.028). Complete pathological response was observed in 11 patients (29.7%) in the standard arm and in 13 patients (59.1%) in the SIB arm (P = 0.026). In the SIB arm mild diarrhea appeared in 59.1%, moderate in 40.9%, and severe in 0% of the cases. In the standard arm mild, moderate, and severe diarrhea rates were in 54.1%, 43.2%, and 2.7%, respectively. In the SIB arm mild, moderate, and severe cystitis appeared in 63.6%, 22.7%, and 13.6%, while in the standard group mild cystitis developed in 67.6%, moderate in 24.3%, and severe in 8.1%. Mild, moderate, and severe radiation dermatitis rates were 45.5%, 45.5%, and 9.1% in the SIB group and 40.5%, 48.6%, and 10.8% in the standard group, respectively.

Conclusion

The SIB-VMAT technique is effective and safe for irradiating locally advanced rectal cancer. Its effectiveness is expressed in higher clinical and pathological complete response rates and safety with the same rates of acute toxicity.

Induction Chemotherapy Reduces Patient-reported Toxicities During Neoadjuvant Chemoradiation with Intensity Modulated Radiotherapy for Rectal Cancer

BACKGROUND

Initial treatment with either neoadjuvant chemoradiation (CRT) or induction FOLFOX (5-Fluorouracil, leucovorin, and oxaliplatin) chemotherapy followed by CRT is considered standard treatment for locally advanced rectal cancer. We compared patient-reported outcomes (PRO) during CRT in patients who had received induction chemotherapy versus those who did not.

PATIENTS AND METHODS

We reviewed records of patients with locally advanced rectal cancer who were treated with CRT between September 2009 and October 2014, and who had completed ≥ 4 PRO assessments during treatment. Clinician- and patient-reported toxicities were collected each week during treatment. We fit binomial generalized linear models to maximum toxicity scores across all patients' visits.

RESULTS

Of 123 patients with ≥ 4 PRO assessments, 87 (71%) patients reported a clinically meaningful PRO score of 3 or higher for diarrhea, and 91 (74%) patients reported a PRO score of ≥ 3 for urgency, during 1 or more weeks of treatment, corresponding to 'very frequent' or worse. Of 116 patients who had also completed ≥ 4 clinician-reported assessments for descriptive analysis, clinically significant diarrhea (Common Terminology Criteria for Adverse Events grade ≥ 2) was reported in 9% of patients, and grade 2 proctitis and cystitis were reported in 20% and 4%, respectively. Eighty-four (68%) patients had undergone induction chemotherapy prior to CRT. Patients who received induction chemotherapy had 68% lower odds of experiencing significant urgency (odds ratio [OR], 0.32; 95% confidence interval [CI], 0.11-0.95; P = .04), 76% lower odds of bleeding (OR, 0.24; 95% CI, 0.1-0.62; P < .01), and 75% lower odds of tenesmus (OR, 0.25; 95% CI, 0.11-0.6; P < .01) versus those treated with upfront CRT.

CONCLUSION

Based on PROs, a high proportion of patients experienced clinically significant symptoms during pelvic CRT, with diarrhea and urgency being most commonly reported. This appears to be under-reported on clinician-reported assessments. Delivery of induction chemotherapy was associated with lower odds of experiencing urgency, bleeding, and tenesmus on PROs during subsequent CRT, with no significant impact on diarrhea and rectal pain.

Phase I study of preoperative chemoradiotherapy with sequential oxaliplatin and irinotecan with S-1 for locally advanced rectal cancer

The present study designed a novel preoperative chemoradiotherapy (CRT) with sequential oxaliplatin and irinotecan with S-1 for locally advanced rectal cancer (LARC). This phase I study evaluated the maximum tolerated dose and recommended dose (RD) of oxaliplatin following irinotecan with S-1. Patients with clinical stage T3 or 4 or involvement of the regional nodes and no evidence of distant metastases were treated with fixed doses of S-1 (80 mg/m²/day) on days 1-5, 8-12, 15-19, 22-27 and 29-33, and irinotecan (40 mg/m²/day) on days 1 and 8, followed by oxaliplatin on days 22 and 29. The dose of oxaliplatin was initially 40 mg/m² (level 1) with a predefined dose escalation schedule. The radiation dose was 1.8 Gy/fraction to a total dose of 45 Gy. A total of 9 patients were enrolled in the present study and 7 patients completely received CRT with this study protocol. The maximum tolerated dose for oxaliplatin was 50 mg/m² (level 2). Three of four patients experienced dose-limiting toxicity (grade 3 diarrhea) in oxaliplatin phase of level 2 dose. The RD of oxaliplatin was 40 mg/m² (level 1 dose). In addition, 2 patients had pathological CR (28.5%). Novel preoperative CRT with sequential oxaliplatin and irinotecan with S-1 for LARC resulted in acceptable toxicity and promising efficacy. However, the RD of oxaliplatin was lower than in previous CRT studies that combined oxaliplatin with S-1. To administer higher oxaliplatin, we have planned a phase I trial of preoperative CRT with sequential oxaliplatin followed by irinotecan with S-1 for LARC.

Neoadjuvant chemoradiation for locally advanced rectal cancer: a systematic review of the literature with network meta-analysis

Background

Neoadjuvant chemoradiotherapy (CRT) prior to surgery is a standard therapy for locally advanced rectal cancer, but the optimum regime is not conclusive. This meta-analysis evaluated various CRT regimens with regard to the rate of pathologic complete response (pCR) and toxic effects of grade ≥3.

Methods

The databases PubMed, Cochrane Library, and Embase were searched for randomized controlled trials (RCTs) that compared neoadjuvant CRT regimes for treating patients with locally advanced rectal cancer, published before 28 December 2017. The primary end points were pCR and toxic effects. A network meta-analysis was applied.

Results

Fourteen RCTs (with 5,599 participants) involving the following eight regimens were included: fluorouracil (5FU) alone, or 5FU with oxaliplatin (OXA), cisplatin, or irinotecan (CPT-11); capecitabine (CAP) alone, or CAP with OXA or CPT-11; and CPT-11 with combined tegafur, 5-chloro-2,4-dihydroxypyridine, and potassium oxonate. The rate of pCR associated with CAP + OXA was significantly higher compared with 5FU alone; there were no significant differences among the other regimens. The toxicity of 5FU + OXA or CAP + OXA was significantly worse than that of 5FU alone or CAP alone. CAP + OXA and CAP were ranked, respectively, the most and second most effective regimens in terms of pCR rate. 5FU alone and CAP alone likely had the lowest and second lowest toxicity, respectively.

Conclusion

Among the currently available CRT regimens for locally advanced rectal cancer, this meta-analysis indicated that CAP + OXA provides the superior clinical results. Adding OXA to 5FU or CAP significantly increases toxicity.

Lymphocyte nadir predicts tumor response and survival in locally advanced rectal cancer after neoadjuvant chemoradiotherapy: Immunologic relevance

BACKGROUND AND PURPOSE

Neoadjuvant chemoradiation (nCRT) could reduce tumor infiltrating lymphocytes. We examined absolute lymphocyte count (ALC) nadir during nCRT, pathologic response and prognosis for locally advanced rectal cancer (LARC).

MATERIALS AND METHODS

102 patients with LARC (cT3-4N0, or node-positive) treated between 2010 and 2015 with nCRT followed by complete resection were analyzed. The ALC value was obtained prior to, weekly during the treatment, and one month after nCRT. Associations of ALC nadir with immune cells' infiltrations, pathologic response and survival were analyzed.

RESULTS

Twenty-four (23.5%) and 60 (58.9%) patients achieved pathologic complete response and partial response respectively. Response rate was higher in high ALC nadir group than low nadir group (89.7% vs. 67.6%, p = 0.006). Compared to low ALC nadir group, increased tumor infiltrates of CD4+ (4% vs. 17.5%, p < 0.001), CD8+ (8% vs.30%, p < 0.001) T cells and CD68+ macrophages (6% vs. 25%, p < 0.001) were observed in high ALC nadir group. High ALC nadir [OR = 4.32 (95% CI, 1.22-15.26), p = 0.023] and well differentiation [OR = 10.53 (1.87-59.36), p = 0.008] were associated with pathologic response. Patients with high ALC nadir yielded better DFS [HR = 0.36 (0.16-0.81), p = 0.010] and OS [HR = 0.24 (0.08-0.69), p = 0.004].

CONCLUSIONS

Higher ALC nadir during nCRT is associated with a higher rate of pathologic response and better survival for LARC patients, suggesting that ALC may be a potential stratification strategy for LARC patients.

Radiosensitization by irinotecan is attributed to G2/M phase arrest, followed by enhanced apoptosis, probably through the ATM/Chk/Cdc25C/Cdc2 pathway in p53-mutant colorectal cancer cells

Irinotecan, an analog of camptothecin, which is an inhibitor of topoisomerase I, is currently used in the treatment of metastatic colorectal cancer. Camptothecin derivatives have been demonstrated to exert radiosensitizing effects on several types of cancer cells. However, to date, at least to the best of our knowledge, few studies have examined these effects in colorectal cancer cell lines. In the present study, we examined the radiosensitizing effects of irinotecan on the p53-mutant colorectal cancer cell lines, HT29 and SW620, and explored the potential underlying mechanisms. Drug cytotoxicity tests revealed that the 24 h half-maximal inhibitory concentrations (IC50s) of irinotecan as a single agent were 39.84 µg/ml (HT29 95% CI, 38.27-41.48) and 96.86 µg/ml (SW620 95% CI, 89.04-105.4); finally, concentrations <2 µg/ml were used in the subsequent experiments. Clonogenic assays revealed that irinotecan exerted radiosensitizing effects on the HT29 and SW620 cells, and the sensitivity enhancement ratios (SERs) at 2 Gy increased with increasing concentrations (SER at 2 Gy, 1.41 for the HT29 cells, 1.87 for the SW620 cells; with irinotecan at 2 µg/ml). Subsequently, the cells were divided into 4 groups: The control group, irinotecan group, radiation group and combination group. Compared with the control, irinotecan and radiation groups, the combination group had the slowest cell growth rate and the most obvious foci of Ser139p‑γH2AX. Combined treatment resulted in a firstly decreased and then increased M phase arrest and led to the most significant G2/M phase arrest, followed by the most significant increase in apoptosis. The results of western blot analysis indicated that the expression levels of proteins related to the DNA damage response system (Ser1981p‑ATM, Ser345p‑Chk1, Thr68p‑Chk2 and Ser139p‑γH2AX) and the cell cycle (Tyr15p‑Cdc2 and cyclin B1) exhibited the greatest increase in the combined group. In addition, the expression of Ser216p‑Cdc25C was also increased in the combined group, indicating that irinotecan likely radiosensitized the p53-mutant HT29 and SW620 cells through the ATM/Chk/Cdc25C/Cdc2 pathway.

Pathological complete response of locally advanced colon cancer after preoperative radiotherapy: a case report and narrative review of the literature

Background

The oncological effectiveness of preoperative radiotherapy for locally advanced colon cancer is unclear. We report a case of pathological complete response in a patient with locally advanced ascending colon cancer after preoperative radiotherapy following failure of chemotherapy.

Case presentation

A 65-year-old Japanese woman presented with malaise and hematochezia. A computed tomography (CT) revealed a tumor in the ascending colon which seemed to infiltrate the adjacent structures. She was diagnosed with locally advanced ascending colon cancer stages T4b, N2a, M0, and IIIC. We selected modified FOLFOX6 with panitumumab as neoadjuvant chemotherapy. However, we discontinued the chemotherapy after the 8th cycle because of disease progression and severe adverse effects. The patient then underwent radiotherapy of 60 Gy in 30 fractions, resulting in significant tumor size reduction. One month after the radiotherapy, we performed a right hemicolectomy with multivisceral resection without complications. Histopathologically, we found no residual cancer cells in the resected specimen. The patient remains alive and has not required additional therapies for 24 months, as there are no signs of recurrence.

Conclusions

The present case suggests that preoperative radiotherapy might be an effective treatment options for locally advanced colon cancer.

Genotype-driven phase I study of weekly irinotecan in combination with capecitabine-based neoadjuvant chemoradiation for locally advanced rectal cancer

PURPOSE

We aimed to identify the maximum tolerated dose (MTD) of weekly irinotecan in combination with capecitabine-based neoadjuvant chemoradiation according to the UGT1A1∗28 genotype in patients with locally advanced rectal cancer.

PATIENTS AND METHODS

Patients with clinical stage T3-4, N0-2 who were eligible for preoperative chemoradiotherapy were screened for the UGT1A1∗28 genotype. Twenty-six patients with either the ∗1∗1 or ∗1∗28 genotype were eligible for dose escalation of irinotecan, and patients with a ∗28∗28 genotype were excluded. The starting dose of weekly irinotecan was 50 mg/m² for the two genotype groups, whereas the dose of capecitabine was fixed at 625 mg/m². Intensity-modulated radiation therapy (IMRT) was applied to the whole pelvis (total dose of 50 Gy in 25 fractions).

RESULTS

The dose of weekly irinotecan was escalated to 95 mg/m² in patients with the ∗1∗1 genotype and to 80 mg/m² in those with the ∗1∗28 genotype. Dose-limiting toxicities (DLTs) were observed in 2/2 ∗1∗1 patients at 95 mg/m² and 2/3 ∗1∗28 patients at 80 mg/m². No DLT cases were observed among the three ∗1∗1 patients at 80 mg/m², and one DLT case was observed among the six patients with ∗1∗28 at 65 mg/m². Hence, 80 mg/m² and 65 mg/m² were the MTDs for the two groups. The most common grade 3 to 4 toxicities were neutropenia and diarrhea.

CONCLUSION

A higher dose of weekly irinotecan in combination with capecitabine-based CRT is feasible under the guidance of the UGT1A1∗28 genotype. Further clinical trials at these dose levels are warranted.

Adjuvant chemotherapy for ypT0N0M0 rectal cancer following chemoradiotherapy and total mesorectal excision

The management of adenocarcinoma of the rectum is a dynamic field in oncology. The multidisciplinary approach to the management of this disease continues to evolve in each segment of its trimodality treatment. New scheduling regimens and radiosensitizing agents continue to emerge. Although total mesorectal excision continues to be the operation of choice for rectal cancers, what is done before and after surgery continues to evolve to maximize an ideal oncologic outcome with minimal morbidity. The achievement of a pathological complete response [pCR (i.e. ypT0N0)] in a fraction of patients undergoing neoadjuvant chemoradiation poses an interesting management dilemma. The cohort of patients who can achieve a pCR have superior oncologic outcomes compared to nonresponders. The present review addresses the need for adjuvant therapy in patients with a pCR. We discuss the evolution of the role of adjuvant therapy in patients with rectal cancer and the studies addressing the elimination of this strategy in all patients with rectal cancer with a goal of determining the current evidence that might result in the omission of adjuvant therapy for patients with ypT0N0 rectal cancer after chemoradiation and total mesorectal excision.

The potential usefulness of the Response Index in positron emission tomography assessing the therapeutic effect of pre-operative chemotherapy for advanced colorectal cancer

BACKGROUND AND PURPOSE

Pre-operative chemotherapy is an option for patients with local advanced rectal cancer, but the response rate to pre-operative chemotherapy with oxaliplatin is still low. If the therapeutic effect of pre-operative chemotherapy could be assessed, we may be able to convert to surgery early. The purpose of the present study was to validate the correlation between the maximum standardized uptake value (SUV_max) in 18F-fluorodeoxyglucose positron emission tomography-computed tomography (PET-CT) of the primary tumor and the therapeutic effect of pre-operative chemotherapy in advanced colorectal cancer.

PATIENTS AND METHODS

Retrospective cohort study from January 2011 to October 2015. We examined 28 patients with pathologically confirmed sigmoid or rectal cancer that underwent pre-operative chemotherapy and surgery. The correlation between Response Index (RI), calculated as (SUV_max after chemotherapy)/(SUV_max before chemotherapy), and the therapeutic effect on the primary tumor in advanced colorectal cancer.

RESULTS

The degree of differentiation (p = 0.04), SUV_max in the primary tumor after chemotherapy (p = 0.02), and RI (p = 0.008) were significant predictors of the therapeutic effect in univariate analysis. The areas under the ROC curve constructed with RI and therapeutic effect was 0.77. The optimal cut-off values for the RI in the responder group was < 0.32.

CONCLUSION

RI calculated as (SUV_max after chemotherapy)/(SUV_max before chemotherapy) in the primary tumor significantly correlated with the therapeutic effect of chemotherapy on advanced colorectal cancer. Thus, RI is potentially useful for predicting the therapeutic effect in advanced colorectal cancer.

Phase 2 Neoadjuvant Treatment Intensification Trials in Rectal Cancer: A Systematic Review

PURPOSE

Multiple phase 2 trials of neoadjuvant treatment intensification in locally advanced rectal cancer have reported promising efficacy signals, but these have not translated into improved cancer outcomes in phase 3 trials. Improvements in phase 2 trial design are needed to reduce these false-positive signals. This systematic review evaluated the design of phase 2 trials of neoadjuvant long-course radiation or chemoradiation therapy treatment intensification in locally advanced rectal cancer.

METHODS AND MATERIALS

The PubMed, EMBASE, MEDLINE, and Cochrane Library databases were searched for published phase 2 trials of neoadjuvant treatment intensification from 2004 to 2016. Trial clinical design and outcomes were assessed, with statistical design and compliance rated using a previously published system. Multivariable meta-regression analysis of pathologic complete response (pCR) was conducted.

RESULTS

We identified 92 eligible trials. Patients with American Joint Committee on Cancer stage II and III equivalent disease were eligible in 87 trials (94.6%). In 43 trials (46.7%), local staging on magnetic resonance imaging was mandated. Only 12 trials (13.0%) were randomized, with 8 having a standard-treatment control arm. Just 51 trials (55.4%) described their statistical design, with 21 trials (22.8%) failing to report their sample size derivation. Most trials (n=84, 91.3%) defined a primary endpoint, but 15 different primary endpoints were used. All trials reported pCR rates. Only 38 trials (41.3%) adequately reported trial statistical design and compliance. Meta-analysis revealed a pooled pCR rate of 17.5% (95% confidence interval, 15.7%-19.4%) across treatment arms of neoadjuvant long-course radiation or chemoradiation therapy treatment intensification and substantial heterogeneity among the reported effect sizes (I² = 55.3%, P<.001). Multivariable meta-regression analysis suggested increased pCR rates with higher radiation therapy doses (adjusted P=.025).

CONCLUSIONS

Improvement in the design of future phase 2 rectal cancer trials is urgently required. A significant increase in randomized trials is essential to overcome selection bias and determine novel schedules suitable for phase 3 testing. This systematic review provides key recommendations to guide future treatment intensification trial design in rectal cancer.

Complete Neoadjuvant Treatment for Rectal Cancer: The Brown University Oncology Group CONTRE Study

PURPOSE

Following preoperative chemoradiation and surgery, many patients with stage II to III rectal cancer are unable to tolerate full-dose adjuvant chemotherapy. BrUOG R-224 was designed to assess the impact of COmplete Neoadjuvant Treatment for REctal cancer (CONTRE), primary chemotherapy followed by chemoradiation and surgery, on treatment delivery, toxicities, and pathologic response at surgery.

METHODS

Patients with clinical stage II to III (T3 to T4 and/or N1 to N2) rectal cancer received 8 cycles of modified FOLFOX6 followed by capecitabine 825 mg/m bid concurrent with 50.4 Gy intensity-modulated radiation therapy. Surgery was performed 6 to 10 weeks after chemoradiation.

RESULTS

Thirty-nine patients were enrolled between August 2010 and June 2013. Median age was 61 years (30 to 79 y); 7 patients (18%) were clinical stage II and 32 (82%) stage III. Thirty-six patients (92%) received all 8 cycles of mFOLFOX6, of whom 35 completed subsequent chemoradiation; thus 89% of patients received CONTRE as planned. No unexpected toxicities were reported. All patients had resolution of bleeding and improvement of obstructive symptoms, with no complications requiring surgical intervention. Pathologic complete response (ypT0N0) was demonstrated in 13 patients (33%; 95% CI, 18.24%-47.76%).

CONCLUSIONS

CONTRE seems to be a well-tolerated alternative to the current standard treatment sequence. Evaluating its impact on long-term outcomes would require a large randomized trial, but using pathologic response as an endpoint, it could serve as a platform for assessing the addition of novel agents to preoperative treatment in stage II to III rectal cancer.

Effect of Neoadjuvant Chemoradiotherapy on Locally Advanced Rectal Mucinous Adenocarcinoma: A Propensity Score-Matched Study

Aims. To compare the surgical and oncological outcomes of rectal mucinous adenocarcinomas treated with neoadjuvant chemoradiotherapy versus surgery alone. Methods. A total of 167 locally advanced rectal mucinous adenocarcinoma patients treated with neoadjuvant chemoradiotherapy and surgery alone between 2008 and 2014 were matched using propensity score; the surgical and oncological outcomes were compared. Results. Ninety-six patients were matched. Postoperative morbidity was similar between groups. Sphincter preservation rate was higher in patients receiving neoadjuvant chemoradiotherapy (79.2% versus 60.4%, P = 0.045), especially for tumors ≥ 3 cm but ≤5 cm from the anal verge (75.0% versus 44.0%, P = 0.036). With a median follow-up of 54.8 months, the 5-year overall survival rate (neoadjuvant chemoradiotherapy versus surgery alone: 79.6% versus 67.1%; P = 0.599) and disease-free survival rate (75.6% versus 64.2%; P = 0.888) were similar. The 5-year local recurrence rate was lower in patients receiving neoadjuvant chemoradiotherapy (7.7% versus 26.0%, P = 0.036), while no difference was observed in distant metastasis. A poor response to chemoradiation was associated with higher local recurrence (P = 0.037). Conclusions. Compared with surgery alone, neoadjuvant chemoradiotherapy was found to increase the sphincter preservation rate and reduce local recurrence, thus being beneficial for locally advanced rectal mucinous adenocarcinoma patients.

Prognostic influence of histopathological regression patterns in rectal adenocarcinoma receiving neoadjuvant therapy

BACKGROUND

Neoadjuvant chemoradiation therapy (CRT) is an important management strategy in rectal carcinoma. Different systems grading response have shown varying prognostic influence.

METHODS

To analyze the prognostic influence of pathological response in a series of 183 patients with rectal carcinoma receiving neoadjuvant therapy. To determine the prognostic significance of the histopathological patterns of response.

RESULTS

A total of 183 patients from two hospitals. The concordance rate between pathologists was good. In total, 18% of the patients showed grade 0 (complete response), 31.7% grade 1, 19.2% grade 2 and 31.1% grade 3 regression. T down-staging was found in 51.9% of the cases. 46 patients recurred and 18 died of disease (median follow-up time: 39 months). We found a statistically significant association between pathological response and pT stage and down-staging. Inflammatory reaction in the tumor bed was significantly associated to regression and prognosis. Cox's multivariate analysis of survival revealed that down-staging and presence of mucin pools in the tumor bed behaved as significant predictors of recurrence and regression grade and mucin pools as significant predictors of survival.

CONCLUSIONS

Pathological response is an important surrogate marker of prognosis in some large series, but results are varying. There are many systems to grade regression and this makes it difficult to compare the results by different groups. It is important to report the specific pattern of response, for some of them may have prognostic relevance. We feel there is an urgent need to develop standarized protocols and employ a universal regression scheme if we intend to use this factor to guide therapy.

Combined Modality Therapy for Rectal Cancer

The primary therapy for any potentially curative rectal cancer is surgery. For locally advanced tumors (i.e., T3-4 and/or node positive), the very high rate of local and distant recurrences has necessitated a standard adjuvant regimen of preoperative chemoradiation and postoperative chemotherapy. Several controversies regarding this approach remain, including the technique and fractionation scheme of radiation therapy prior to surgery, the choice of concomitant chemotherapy, and whether all patients require postoperative systemic therapy. Furthermore, in an era of improving staging imaging and surgical techniques, an opportunity for de-escalation of therapy to improve patient morbidity and quality of life may arise. At the same time, advances in radiation and systemic therapy may help facilitate less invasive, sphincter-preserving surgery. This review addresses these questions and others that remain areas of active clinical investigation.

An update on the multimodality of localized rectal cancer

New strategies have reduced the local recurrence (LR) rate and extended the duration of overall survival (OS) in patients with localized rectal cancer (RC) in recent decades. The mainstay of curative treatment remains radical surgery; however, downsizing the tumor by neo-adjuvant chemo-radiotherapy and adjuvant cytotoxic therapy for systemic disease has shown significant additional benefit. The standardization of total mesorectal excision (TME), radiation treatment (RT) dose and fractionation, and optimal timing and sequencing of treatment modalities with the use of prolonged administration of fluoropyrimidine concurrent with RT have significantly decreased the rates of LR in locally advanced rectal cancer (LARC) patients. This review focuses on the optimization of multi-modality therapies in patients with localized RC.

Acute toxicity with intensity modulated radiotherapy versus 3-dimensional conformal radiotherapy during preoperative chemoradiation for locally advanced rectal cancer

BACKGROUND AND PURPOSE

We examined acute toxicity profiles and outcomes among rectal cancer patients treated with pre-operative chemoradiation using intensity modulated radiotherapy (IMRT) or 3-dimensional conformal radiotherapy (3DCRT) to identify predictive clinical factors associated with increased acute toxicity.

MATERIAL AND METHODS

We retrospectively reviewed records of 301 consecutive rectal cancer patients treated with pre-operative chemotherapy and radiotherapy (median dose 5000cGy) at our institution between 2007 and 2014.

RESULTS

Of the 301 patients, 203 (67.4%) were treated with IMRT and 98 (32.6%) with 3DCRT. Significantly more patients experienced ⩾grade 2 diarrhea in the 3DCRT group compared to the IMRT group (22% vs 10%, p=0.004), and those who received 3DCRT had 2.7 times greater odds of a higher diarrhea score than those on IMRT, even after adjusting for patient characteristics and chemotherapy (OR 2.71, p=0.01) Fewer patients experienced grade 2 genitourinary toxicity in the IMRT group (6% vs 13% 3DCRT, p=0.04) and there was a trend toward decreased grade 2 proctitis in the IMRT group (22% vs 32% 3DCRT, p=0.07). Patients over the age of 55 had 45% lower odds of proctitis than patients younger than 55.

CONCLUSION

The use of IMRT significantly reduced grade ⩾2 diarrhea and GU toxicity during chemoradiation. Younger patients were more likely to report grade 2 or higher proctitis.

Does Extending the Waiting Time of Low-Rectal Cancer Surgery after Neoadjuvant Chemoradiation Increase the Perioperative Complications?

Background. Traditionally, rectal cancer surgery is recommended 6 to 8 weeks after completing neoadjuvant chemoradiation. Extending the waiting time may increase the tumor response rate. However, the perioperative complication rate may increase. The purpose of this study was to determine the association between extending the waiting time of surgery after neoadjuvant chemoradiation and perioperative outcomes. Methods. Sixty patients with locally advanced rectal cancer who underwent neoadjuvant chemoradiation followed by radical resection at Siriraj hospital between June 2012 and January 2015 were retrospectively analyzed. Demographic data and perioperative outcomes were compared between the two groups. Results. The two groups were comparable in term of demographic parameters. The mean time interval from neoadjuvant chemoradiation to surgery was 6.4 weeks in Group A and 11.7 weeks in Group B. The perioperative outcomes were not significantly different between Groups A and B. Pathologic examination showed a significantly higher rate of circumferential margin positivity in Group A than in Group B (30% versus 9.3%, resp.; P = 0.04). Conclusions. Extending the waiting to >8 weeks from neoadjuvant chemoradiation to surgery did not increase perioperative complications, whereas the rate of circumferential margin positivity decreased.

Timing of surgery following neoadjuvant chemoradiotherapy in locally advanced rectal cancer - A comparison of magnetic resonance imaging at two time points and histopathological responses

PURPOSE

There is wide inter-institutional variation in the interval between neoadjuvant chemoradiotherapy (NACRT) and surgery for locally advanced rectal cancer. We aimed to assess the association of magnetic resonance imaging (MRI) at 9 and 14 weeks post-NACRT; T-staging (ymrT) and post-NACRT tumour regression grading (ymrTRG) with histopathological outcomes; histopathological T-stage (ypT) and histopathological tumour regression grading (ypTRG) in order to inform decision-making about timing of surgery.

PATIENTS AND METHODS

We prospectively studied 35 consecutive patients (26 males) with MRI-defined resection margin threatened rectal cancer who had completed standardized NACRT. Patients underwent a MRI at Weeks 9 and 14 post-NACRT, and surgery at Week 15. Two readers independently assessed MRIs for ymrT, ymrTRG and volume change. ymrT and ymrTRG were analysed against histopathological ypT and ypTRG as predictors by logistic regression modelling and receiver operating characteristic (ROC) curve analyses.

RESULTS

Thirty-five patients were recruited. Inter-observer agreement was good for all MR variables (Kappa > 0.61). Considering ypT as an outcome variable, a stronger association of favourable ymrTRG and volume change at Week 14 compared to Week 9 was found (ymrTRG - p = 0.064 vs. p = 0.010; Volume change - p = 0.062 vs. p = 0.007). Similarly, considering ypTRG as an outcome variable, a greater association of favourable ymrTRG and volume change at Week 14 compared to Week 9 was found (ymrTRG - p = 0.005 vs. p = 0.042; Volume change - p = 0.004 vs. 0.055).

CONCLUSION

Following NACRT, greater tumour down-staging and volume reduction was observed at Week 14. Timing of surgery, in relation to NACRT, merits further investigation.

TRIAL REGISTRATION NUMBER

NCT01325909.

Association of thymidylate synthase polymorphisms with the tumor response to preoperative chemoradiotherapy in rectal cancer: a systematic review and meta-analysis

Preoperative chemoradiotherapy (pCRT) followed by surgery is currently the standard therapy for patients with locally advanced rectal cancer. It is very important to develop biomarkers to prior identify the patients who have a higher likelihood of responding to pCRT. Recently, a series of studies have been conducted to investigate the association of thymidylate synthase (TYMS) polymorphisms with the tumor response to pCRT in rectal cancer, but the results were not consistent and conclusive. In the present study, we performed a systematic literature search for relevant studies up to 30 March 2015 and conducted a meta-analysis to summarize and clarify the association between the TYMS polymorphisms and the tumor response to pCRT in rectal cancer. Finally, 7 studies containing 892 cases for TYMS 2R/3R polymorphism, 7 studies involving 715 cases for TYMS 1494del6 polymorphism and 6 studies containing 616 cases for TYMS 5' untranslated region (UTR) expression allele polymorphism were analyzed in the meta-analysis. The results suggested that TYMS 2R/3R was associated with the response and the patients with 2R/2R or 2R/3R genotype with rectal cancer might benefit more from pCRT than others. On the contrary, neither 1494del6 nor 5'UTR expression allele polymorphisms was associated with the response to pCRT.

Watch and wait approach to rectal cancer: A review

In 2014, there were an estimated 136800 new cases of colorectal cancer, making it the most common gastrointestinal malignancy. It is the second leading cause of cancer death in both men and women in the United States and over one-third of newly diagnosed patients have stage III (node-positive) disease. For stage II and III colorectal cancer patients, the mainstay of curative therapy is neoadjuvant therapy, followed by radical surgical resection of the rectum. However, the consequences of a proctectomy, either by low anterior resection or abdominoperineal resection, can lead to very extensive comorbidities, such as the need for a permanent colostomy, fecal incontinence, sexual and urinary dysfunction, and even mortality. Recently, trends of complete regression of the rectal cancer after neoadjuvant chemoradiation therapy have been confirmed by clinical and radiographic evaluation-this is known as complete clinical response (cCR). The “watch and wait” approach was first proposed by Dr. Angelita Habr-Gama in Brazil in 2009. Those patients with cCR are followed with close surveillance physical examinations, endoscopy, and imaging. Here, we review management of rectal cancer, the development of the “watch and wait” approach and its outcomes.

The Impact of Preoperative Radiation Therapy on Locoregional Recurrence in Patients with Stage IV Rectal Cancer Treated with Definitive Surgical Resection and Contemporary Chemotherapy

PURPOSE

Definitive resection of primary rectal cancers is frequently incorporated, with or without preoperative radiotherapy and perioperative chemotherapy, in the management of selected patients with metastatic rectal adenocarcinoma. This study reviews the impact of preoperative radiotherapy and perioperative chemotherapy on locoregional recurrence and overall survival in these patients.

METHODS AND MATERIALS

This retrospective study with an Institutional Review Board (IRB) waiver included 109 patients with metastatic rectal adenocarcinoma who underwent definitive primary resection between 1998 and 2011. In addition to resection, 64 patients were treated with preoperative radiotherapy and perioperative chemotherapy and 45 patients were treated with perioperative chemotherapy alone. Radiotherapy dose was typically 50.4 Gy. Baseline variables were compared using chi-square and unpaired t tests. Overall survival was calculated using Kaplan-Meier method. Univariate and multivariate analyses were performed using Cox proportional hazards regression.

RESULTS

There were no significant baseline differences between the two groups. There was no significant difference in locoregional recurrence (10.9 vs. 11.1%; p = 0.90) or overall survival (34.5 vs. 34.8 months; p = 0.89) for patients treated with preoperative radiotherapy compared to those treated with perioperative chemotherapy alone, respectively. Patients who underwent radiotherapy were less likely to have a positive margin (10.9 vs. 20.0%; p = 0.19), lymphovascular invasion (32.8 vs. 53.3%; p = 0.03), and pathologic stage N2 disease (25.0 vs. 42.2%; p = 0.02). Grade 2 postoperative complications were more common in the preoperative radiotherapy group (32.8 vs. 15.6%; p = 0.04). Multivariate analysis demonstrated that patients with poorly differentiated tumors (HR 2.19; p = 0.009) and those that did not undergo liver-directed therapy (HR 2.20; p = 0.005) had inferior survival.

CONCLUSIONS

Locoregional recurrence is modest in patients with metastatic rectal adenocarcinoma receiving definitive primary resection, irrespective of the use of radiotherapy. Preoperative radiotherapy may enhance pathologic downstaging at the expense of increased grade 2 postoperative complications. Its use should be reserved for patients at high risk for locoregional recurrence.

Organ preservation in rectal cancer: current status and future perspectives

With the introduction of population screening initiatives, more patients may be amenable to local, transanal excision (LE) of early-stage rectal cancer. The most important drawback of LE is the risk of understaging node-positive disease. The most powerful predictors of node-positive disease are lymphatic invasion, submucosal invasion depth and width, tumor budding and poor differentiation. Therefore, LE should be reserved for low-risk T1 tumors in those reluctant or unable to undergo major surgery. Neoadjuvant chemoradiation followed by LE for T2 tumors allows adequate local control, and is currently being compared with anterior resection alone in randomized trials. A mere watchful waiting approach has been proposed in clinical complete responders to chemoradiation. However, given the very poor accuracy of current imaging modalities to predict a true pathological complete response, this strategy should not be offered outside of well-controlled trials.

CAPIRI-IMRT: a phase II study of concurrent capecitabine and irinotecan with intensity-modulated radiation therapy for the treatment of recurrent rectal cancer

BACKGROUND

This study investigated the local effect and acute toxicity of irinotecan and capecitabine with concurrent intensity-modulated radiation therapy (IMRT) for the treatment of recurrent rectal cancer without prior pelvic irradiation.

METHODS

Seventy-one patients diagnosed with recurrent rectal cancer who did not previously receive pelvic irradiation were treated in our hospital from October 2009 to July 2012. Radiotherapy was delivered to the pelvis, and IMRT of 45 Gy (1.8 Gy per fraction), followed by a boost of 10 Gy to 16 Gy (2 Gy per fraction), was delivered to the recurrent sites. The concurrent chemotherapy regimen was 50 mg/m(2) irinotecan weekly and 625 mg/m(2) capecitabine twice daily (Mon-Fri). Radical surgery was recommended for medically fit patients without extra-pelvic metastases. The patients were followed up every 3 months. Tumor response was evaluated using CT/MRIs according to the RECIST criteria or postoperative pathological findings. NCI-CTC 3.0 was used to score the toxicities.

RESULTS

Forty-eight patients (67.6%) had confirmed recurrent rectal cancer without extra pelvic metastases, and 23 patients (32.4%) had extra pelvic metastases. Fourteen patients (19.7%) underwent radical resections (R0) post-chemoradiation. A pathologic complete response was observed in 7 of 14 patients. A clinical complete response was observed in 4 patients (5.6%), and a partial response was observed in 22 patients (31.0%). Only 5 patients (7.0%) showed progressive disease during or shortly after treatment. Of 53 symptomatic patients, clinical complete and partial symptom relief with chemoradiation was achieved in 56.6% and 32.1% of patients, respectively. Only 2 patients (2.8%) experienced grade 4 leukopenia. The most common grade 3 toxicity was diarrhea (16 [22.5%] patients). The median follow-up was 31 months. The cumulative local progression-free survival rate was 74.2% and 33.9% at 1 and 3 years after chemoradiation, respectively. The cumulative total survival rate was 80.1% and 36.5% at 1 and 3 years after chemoradiation, respectively.

CONCLUSIONS

This study revealed that concurrent irinotecan and capecitabine with IMRT significantly relieves local symptoms and exhibits promising efficacy with manageable toxicities in recurrent rectal cancer without prior pelvic irradiation. Improving the rate of R0 resections will be investigated in a future study.

Zerumbone increases oxidative stress in a thiol-dependent ROS-independent manner to increase DNA damage and sensitize colorectal cancer cells to radiation

Locally advanced rectal cancers are treated with neoadjuvant chemoradiation therapy followed by surgery. In a minority (~20%) of patients, no tumor is present at the time of surgery; these patients with a complete pathologic response (pathCR) to neoadjuvant therapy have better treatment outcomes. Unfortunately, the inherent radioresistance of colorectal cancer (CRC) cells dictates that the majority of patients do not achieve a pathCR. Efforts to improve these odds have fueled the search for novel, relatively less-toxic radiosensitizers with distinct molecular mechanism(s) and broad-spectrum anticancer activities. Here, we use zerumbone, a sesquiterpene from the edible ginger (Zingiber zerumbet Smith), to enhance radiosensitivity of CRC cells. Short exposure to zerumbone (7 h) profoundly sensitized CRC cells, independent of their p53 or k-RAS status. Zerumbone enhanced radiation-induced cell cycle arrest (G2/M), increased radiation-induced apoptosis, but induced little apoptosis by itself. Zerumbone significantly enhanced radiation-induced DNA damage, as evident by delayed resolution of post-irradiation nuclear γH2AX foci, whereas zerumbone treatment alone did not induce γH2AX foci formation. Zerumbone pretreatment inhibited radiation-induced nuclear expression of DNA repair proteins ataxia-telangiectasia mutated (ATM) and DNA-PKcs. Interestingly, zerumbone-mediated radiosensitization did not involve reactive oxygen species (ROS), but was mediated through depletion of cellular glutathione (GSH). Ability of only thiol-based antioxidants to abrogate zerumbone-mediated radiosensitization further corroborated this hypothesis. The α,β-unsaturated carbonyl group in zerumbone was found to be essential for its bioactivity as zerumbone analog α-Humulene that lacks this functional group, could neither radiosensitize CRC cells, nor deplete cellular GSH. Our studies elucidate novel mechanism(s) of zerumbone's ability to enhance CRC radiosensitivity.

How can we determine the best neoadjuvant chemoradiotherapy regimen for rectal cancer?

SUMMARY 

The current management of patients with clinically defined ‘locally advanced rectal cancer’ often involves fluoropyrimidine-based preoperative chemoradiotherapy (CRT) followed by total mesorectal excision. The focus remains primarily on reducing local recurrence, and improving survival, with organ preservation an increasing target. The best neoadjuvant CRT is the most effective regimen, balanced against the tolerability and late functional consequences, which should be selected for the individual according to their individual risk of local and distant recurrence. Hence, what makes the best neoadjuvant treatment depends on the activity and toxicity of the particular schedule, the aims of treatment, the individual disease characteristics and the individual patient pharmacogenomics. Current research efforts focus on enhancing the efficacy of CRT by integrating additional cytotoxics and biologically targeted agents.