Adjuvant chemotherapy for rectal cancer patients treated with preoperative (chemo)radiotherapy and total mesorectal excision: a Dutch Colorectal Cancer Group (DCCG) randomized phase III trial

Evaluating Complete Response Rates and Predictors in Total Neoadjuvant Therapy for Rectal Cancer

INTRODUCTION

In the management of locally advanced rectal cancer (LARC), there is a paradigm shift from conventional neoadjuvant treatment to total neoadjuvant therapy (TNT). Despite its growing acceptance, there are limited studies have examined its effects on disease presentation. It is also important to determine the factors that play a role in complete response (CR). Our previous data with 119 patients revealed that the CR rate was 37%, and low rectal tumors and the absence of extramural vascular invasion (EMVI) were predictors of CR. Unfortunately, there continues to be a lack of data, and reliable markers are still needed to consistently identify the best respondents. Therefore, we aimed to determine factors associated with CR. We hypothesized that due to the growing patient population, both predictive factors and CR ratio might evolve over time.

METHODS

A retrospective analysis of patients who completed TNT for LARC at our tertiary care center between 2015 and 2022 was performed. Our primary outcome was to determine predictors of CR. As a secondary outcome, we evaluated the 2-year disease-free and overall survival rates. CR consists of patients who sustained clinical CR (cCR) for at least 12 months under WW or had pathological CR (pCR) after surgery.

RESULTS

Out of 339 patients with LARC, 208 (61.3%) successfully completed TNT. Among them, 57 (27.4%) patients achieved cCR, and 80% sustained without tumor regrowth after a year. The remaining 151 (72.6%) patients underwent surgery, and 42 had pCR. The final CR rate was 42.3%. The median age of the patients was 56 (49-66), and 63.5% of the participants were male (n=132), while 36.5% were female (n=76). The median tumor size was 4.95cm (3.6-6.43), with most tumors in the low rectum (119, 57.2%). The MRF involvement rate was 25% (n=52), and EMVI was observed in 20.7% of patients (n=43). based on MRI findings. Low rectal tumors, the absence of MRF involvement, and the absence of EMVI were predicted CR. With a median follow-up of 24.7 months, 2-year disease-free survival and overall survival were significantly higher among patients with CR (91.3% vs 71%, p<0.01 and 98.8% vs 90.2% p=0.03, respectively).

CONCLUSION

In our updated dataset, we observed an increasing CR rate compared to our previous study. In addition to previously identified predictors, low tumor location and the absence of EMVI, we also found the absence of MRF involvement as a predictor of CR. These findings offer valuable insights for clinical practice, helping clinicians set clear expectations when counseling patients.

Trends in incidence, treatment, and relative survival of colorectal cancer in the Netherlands between 2000 and 2021

BACKGROUND

The epidemiology of colorectal cancer (CRC) has changed rapidly over the years. The aim of this study was to assess the trends in incidence, treatment, and relative survival (RS) of patients diagnosed with CRC in the Netherlands between 2000 and 2021.

PATIENTS AND METHODS

2 75667 patients diagnosed with CRC between 2000 and 2021 were included from the Netherlands Cancer Registry. Analyses were stratified for disease extent (localised: T1-3N0M0; regional: T4N0M0/T1-4N1-2M0; distant: T1-4N0-2M1) and localisation (colon; rectum). Trends were assessed with joinpoint regression.

RESULTS

CRC incidence increased until the mid-2010s but decreased strongly thereafter to rates comparable with the early 2000s. Amongst other trend changes, local excision rates increased for patients with localised colon (2021: 13.6 %) and rectal cancer (2021: 34.9 %). Moreover, primary tumour resection became less common in patients with distant colon (2000-2021: 60.9-12.5 %) or rectal cancer (2000-2021: 47.8-6.9 %), while local treatment of metastases rates increased. Five-year RS improved continuously for localised and regional colon (97.7 % and 72.0 % in 2017, respectively) and rectal cancer (95.2 % and 76.3 % in 2017, respectively). The rate of anti-cancer treatments decreased in distant colon (2010-2021: 80.3 % to 67.2 %; p < 0.001) and rectal cancer (2011-2021: 86.0 % to 77.0 %; p < 0.001). The improvement of five-year RS stagnated for distant colon (2010-2017: 11.2 % to 11.9 %; average percentage of change [APC]: 2.1, 95 % confidence interval [CI]: -7.6, 4.7) and rectal cancer (2009-2017: 12.7 % to 15.6 %; APC: 1.4, 95 % CI: -19.1, 5.5).

CONCLUSIONS

Major changes in the incidence and treatment of CRC between 2000 and 2021 were identified and quantified. Five-year RS increased continuously for patients with localised and regional CRC, but stagnated for patients with distant CRC, likely caused by decreased rates of anti-cancer treatment in this group.

Stage IV Rectal Cancer and Timing of Surgical Approach

Liver metastases are seen in at least 60% of patients with colorectal cancer at some point during the course of their disease. The management of both primary and liver disease is uniquely challenging in rectal cancer due to competing treatments and complex sequence of treatments depending on the clinical presentation of disease. Recently, several novel concepts are shaping new treatment paradigms, including changes in timing, sequence, and duration of therapies combined with potential deescalation of treatment components. Overall, the treatment of this clinical scenario mandates multidisciplinary evaluation and personalization of care; however, there is still considerable debate regarding the timing of liver metastasectomy in the context of the overall treatment plan. Herein, we will discuss the current literature on management of rectal cancer with synchronous liver metastasis, current treatment approaches with respect to chemotherapy, and role of hepatic artery infusion therapy.

Oncological Outcomes and Response Rate After Total Neoadjuvant Therapy for Locally Advanced Rectal Cancer: A Network Meta-Analysis Comparing Induction vs. Consolidation Chemotherapy vs. Standard Chemoradiation

TNT is now considered the preferred option for stage II-III locally advanced rectal cancer (LARC). However, the prognostic benefit and optimal sequence of TNT remains unclear. This network meta-analysis (NMA) compared short- and long-term outcomes amongst patients with LARC receiving total neoadjuvant therapy (TNT) as induction (iTNT) or consolidation chemotherapy (cTNT) with those receiving neoadjuvant chemoradiation (nCRT) alone. A systematic literature search was performed between 2012 and 2023. A Bayesian NMA was conducted using a Markov Chain Monte Carlo method with a random-effects model and vague prior distribution to calculate odds ratios (OR) with 95% credible intervals (CrI). The surface under the cumulative ranking (SUCRA) curves were used to rank treatment(s) for each outcome. In total, 11 cohorts involving 8360 patients with LARC were included. There was no significant difference in disease-free survival (DFS) and overall survival (OS) amongst the 3 treatments. Compared with nCRT, both cTNT (OR 2.36; 95% CrI, 1.57-3.66) and iTNT (OR 1.99; 95% CrI, 1.44-2.95) significantly improved complete response (CR) rate. Notably, cTNT ranked as the best treatment for CR (SUCRA 0.90) and iTNT as the best treatment for 3-year DFS and OS (SUCRA 0.72 and 0.87, respectively). Both iTNT and cTNT strategies significantly improved CR rates compared with nCRT. cTNT was ranked highest for CR rates, while iTNT was ranked highest for 3-year survival outcomes. However, no other significant differences in DFS, OS, sphincter-saving surgery, R0 resection and postoperative complications were found amongst the treatment groups.

Predicting survival in locally advanced rectal cancer with effective chemoradiotherapy response

BACKGROUND

Locally advanced rectal cancer patients often display favorable responses and favorable oncologic outcomes. Due to the low recurrence rate, there is scarcity of studies investigating the prognostic factors influencing their survival. Therefore, our study sought to assess the prognostic factors associated with survival in rectal cancer patients who achieved either a pathologic complete response or a pathologic stage I after neoadjuvant chemoradiotherapy combined with radical resection.

METHODS

In this retrospective study, we analyzed data from cohort of 1394 patients diagnosed with locally advanced rectal cancer who underwent neoadjuvant chemoradiotherapy combined with total mesorectal excision from January 2008 to April 2017. Finally, we selected 474 (34.2 %) who exhibited either a pathologic complete response or attained pathologic stage I following the treatment. Subsequently, we analyzed the prognostic factors influencing disease-free and overall survival.

RESULTS

A total of 161 (34 %) achieved a pathologic complete response. Our analysis revealed that circumferential resection margin and the administration of adjuvant chemotherapy were prognostic factors for disease-free survival (p = 0.011, p = 0.022). Furthermore, factors influencing overall survival included the clinical N stage and administration of adjuvant chemotherapy (p = 0.035, p = 0.015).

CONCLUSION

In conclusion, the circumferential resection margin, clinical N stage, and administration of adjuvant chemotherapy were prognostic factors for survival in patients showing good response to neoadjuvant chemoradiotherapy in locally advanced rectal cancer. For patients with a positive circumferential resection margin and clinical N (+) stage, intensive follow-up might be needed to achieve favorable oncologic outcomes. Also, we recommend considering adjuvant chemotherapy as a beneficial treatment approach for these patients.

The role of total neoadjuvant therapy in locally advanced rectal cancer: a survey of specialists attending the All-Ireland Colorectal Cancer Conference 2022 including lead investigators of OPRA, PRODIGE-23 and RAPIDO

BACKGROUND

The treatment of locally advanced rectal cancer (LARC) has evolved following recent landmark trials of total neoadjuvant therapy (TNT)-the delivery of preoperative chemotherapy sequenced with radiation.

AIM

To assess the preferences of colorectal surgery (CRS), radiation oncology (RO) and medical oncology (MO) specialists attending the All-Ireland Colorectal Cancer Conference (AICCC) 2022 regarding the neoadjuvant management of LARC.

METHODS

A live electronic survey explored the preferred treatment approach and TNT regimen for early-, intermediate-, bad-, and advanced-risk categories of rectal cancer according to the European Society of Medical Oncology (ESMO) guidelines. The survey was preceded by an update from lead investigators of TNT trials (OPRA, PRODIGE-23 and RAPIDO), who then participated in a multidisciplinary panel discussion.

RESULTS

Ten CRS, 7 RO and 15 MO (32 of 45 specialists) participated fully in the survey resulting in a response rate of 71%. Ninety-four percent, 76% and 53% of specialists preferred a TNT approach for patients with advanced, bad, and intermediate-risk rectal cancer, respectively. A consolidation TNT regimen of long-course chemoradiotherapy followed by chemotherapy was the most preferred regimen. Upfront surgery was preferred by 77% for early-risk disease.

CONCLUSION

This survey illustrated the general acceptance of TNT by rectal cancer specialists attending the AICCC as a valuable treatment strategy for higher-risk category LARC. Whilst the treatment of LARC changes, it remains best practice to individualize care, incorporating the selective use of TNT as discussed by an MDT and in keeping with the patient's goals of care.

Clinical Outcomes in T4 and/or N2 Rectal Cancer Treated With Neoadjuvant Chemoradiotherapy: A Retrospective Study

INTRODUCTION

Total neoadjuvant therapy (TNT) in the management of locally advanced rectal cancer (LARC) did not show survival benefit over the standard long course chemoradiotherapy. Trials of TNT did not address the impact of each risk feature in isolation from other high-risk features.

METHODOLOGY

In this retrospective study, we describe the clinical outcomes of patients with T4 and/or N2 rectal adenocarcinoma who were treated with chemoradiotherapy followed by total mesorectal excision (TME). After obtaining the local regulatory approvals, demographic and clinical data were collected for patients in Manitoba between January 2007 and December 2019.

RESULTS

The cohort included 331 patients. 61 patients had T4-only disease and 218 had N2-only disease. Mean age was 59.65 years. 74.3% received adjuvant chemotherapy (ACT), but only 56.5% completed the planned course. R0 resection was achieved in 93.4% of patients (78.7% and 97.2% in T4 and N2, respectively). Median follow up was 4.93 years. 3-year overall recurrence rate was 29%. 3-year locoregional recurrence (LRR) rate was 8% (16% and 6% in T4 and N2, respectively). 3-year overall survival (OS) rate was 84% in the whole cohort (72.6% and 87.1% in T4 and N2, respectively). Incomplete surgical resection was a poor prognostic factor for both OS and LRR. ACT was associated with a survival benefit in the whole cohort (P = .001) and in the N2 sub-cohort (P = 003) but there was no survival benefit observed in T4 sub-cohort. ACT did not have an impact on LRR.

CONCLUSIONS

Achieving R0 resection in LARC with neoadjuvant therapy improves recurrence and survival rates. T4 disease carries a worse clinical outcome than N2 and consideration should be given to upstage T4 to stage III. Different high-risk features in LARC predict different clinical outcomes. In the era of TNT, personalization of treatment strategy based on these factors could potentially improve outcomes.

Prediction of survival after neoadjuvant therapy in locally advanced rectal cancer - a retrospective analysis

Purpose

The aim of this retrospective analysis was to determine if the response to preoperative radio(chemo)therapy is predictive for survival among patients with locally advanced rectal cancer and may act as a potential surrogate endpoint for disease free survival and overall survival.

Results

Eight hundred seventy-eight patients from five centers were analyzed. There were 304 women and 574 men; the median age was 64.7 years. 77.6% and 22.4% of patients received neoadjuvant radiochemotherapy or short-course radiotherapy, resulting in a pathological complete response in 7.3%. T-downstaging and N-downstaging occurred in 50.5% and 37% of patients after neoadjuvant therapy. In patients with T-downstaging, the 10-year DFS and 10-year OS were 64.8% and 66.8% compared to 37.1% and 45.9% in patients without T-downstaging. N-downstaging resulted in 10-year DFS and 10-year OS in 56.2% and 62.5% compared to 47.3% and 52.3% without N-downstaging. Based on routinely evaluated clinical parameters, an absolute risk prediction calculator was generated for 5-year disease-free survival, and 5-year overall survival.

Conclusion

T-downstaging and N-downstaging after neoadjuvant radiochemotherapy or short-course radiotherapy resulted in better DFS and OS compared to patients without response. Based on clinical parameters, 5-year DFS, and 5-year OS can be predicted using a prediction calculator.

[An update on total neoadjuvant treatment of adenocarcinoma of the rectum]

A major advance has been made in the management of rectal cancer, with the emergence in 2021 of total neoadjuvant treatment. The main publications from the RAPIDO and PRODIGE-23 trials reported a significant improvement in progression-free survival and the pathological complete response rate. The aim of this review is to synthesize recent data on neoadjuvant treatment of rectal cancer, to explain the long-term results of the RAPIDO and PRODIGE-23 trials, and to put them into perspective, considering current advances in de-escalation strategies. The update of the 5-year survival data from the RAPIDO trial highlights an increased risk of loco-regional relapse, with 11.7% of relapses in the experimental group and 8.1% in the control group, while the update of the PRODIGE-23 trial confirms the benefits of this treatment regimen, with a significant improvement in overall survival. In addition, the results of the OPRA and PROPSPECT trials confirm the benefit of total neoadjuvant treatment with induction chemotherapy, as well as the possibility of surgical de-escalation in the OPRA trial and radiotherapy in the PROSPECT trial. The challenge for the future is to identify patients who require total neoadjuvant treatment with the aim of curative surgery to obtain a cure without local or distant relapse, and those for whom therapeutic de-escalation can be envisaged.

Pretreatment MRI-Based Radiomics for Prediction of Rectal Cancer Outcome: A Discovery and Validation Study

RATIONALE AND OBJECTIVES

Accurate prediction of local recurrence or distant metastasis is critical for developing individualized therapies for locally advanced rectal cancer (LARC) patients after standard therapy. This study aims to develop and validate a multiparameter MRI-based radiomics signature (RS) for prognostic prediction in LARC patients receiving neoadjuvant chemoradiotherapy (nCRT) and total mesorectal excision (TME) and to explore the ability of RS for personalized survival risk stratification.

MATERIALS AND METHODS

In this multi-center study, 454 patients who received nCRT and TME and completed 3 years of follow-up participated. RS was constructed for prognostic prediction based on features extracted from pretreatment multiparameter MRI in a training cohort (TC; n = 298), which was tested in an internal validation cohort (IVC; n = 75) and further validated in an independent external validation cohort (EVC; n = 81). Furthermore, the ability of RS for personalized survival risk stratification was explored using the Kaplan-Meier survival curves.

RESULTS

The RS model showed satisfactory accuracy for prognostic prediction with AUCs of 0.83, 0.81 and 0.82 in the TC, IVC and EVC, respectively. In addition, RS helped to refine risk stratification for LARC patients on the basis of significantly different 3-year disease-free survival rates, independent of their pathological stage, pre-surgery CEA, and even treatment modality.

CONCLUSIONS

The proposed RS can be used not only to predict local recurrence or distant metastasis but also to serve as an effective postoperative survival risk stratification tool for clinicians to facilitate decision-making for LARC patients receiving standard treatment.

The current multidisciplinary management of rectal cancer

Multidisciplinary management of rectal cancer has rapidly evolved over the last several years. This review describes recent data surrounding total neoadjuvant therapy, organ preservation, and management of lateral pelvic lymph nodes. It then presents our treatment algorithm for management of rectal cancer at The University of Texas MD Anderson Cancer Center in the context of this and other existing literature. As part of this discussion, the review describes how we tailor management based upon both patient and tumor-related factors in an effort to optimize patient outcomes.

Advancing Personalized Medicine in the Treatment of Locally Advanced Rectal Cancer

Rectal cancer presents a significant burden globally, often requiring multimodal therapy for locally advanced cases. Long-course chemoradiotherapy (LCRT) and short-course radiotherapy (SCRT) followed by surgery have been conventional neoadjuvant approaches. Recent trials favor LCRT due to improved local control. However, distant tumor recurrence remains a concern, prompting the exploration of total neoadjuvant therapy (TNT) as a comprehensive treatment strategy. Immune checkpoint inhibitors (ICIs) show promise, particularly in mismatch repair-deficient (dMMR) or microsatellite instability-high (MSI-H) tumors, potentially revolutionizing neoadjuvant regimens. Nonoperative management (NOM) represents a viable alternative post-neoadjuvant therapy for selected patients achieving complete clinical response (cCR). Additionally, monitoring minimal residual disease (MRD) using circulating tumor DNA (ctDNA) emerges as a non-invasive method for the assessment of treatment response. This review synthesizes current evidence on TNT, ICIs, NOM, and ctDNA, elucidating their implications for rectal cancer management and highlighting avenues for future research and clinical application.

Total neoadjuvant therapy for locally advanced rectal cancer: a three-group propensity score matched study

PURPOSE

Total neoadjuvant therapy (TNT) has emerged as a therapeutic approach for locally advanced rectal cancer (LARC). However, the optimal chemotherapy cycles within TNT remain uncertain. This study aimed to evaluate and compare the prognostic efficacy of varying cycles of chemotherapy during TNT for LARC.

METHODS

Patients diagnosed with LARC (T3-4N0M0/T1-4N1-2M0), who underwent TNT or chemoradiotherapy followed by total mesorectal excision (TME) between 2015 and 2020, were retrospective included. Patients were categorized into three groups based on their neoadjuvant strategy: CRT (long-course chemoradiotherapy), STNT (long-course CRT with one to three cycles of chemotherapy), and LTNT (long-course CRT with four or more cycles of chemotherapy). Propensity score matching (PSM) based on gender, age, body mass index, tumor distance from the anal verge, clinical T stage, clinical N stage, and mesorectal fascia status was employed to reduce confounding bias. Primary endpoints were disease-free survival (DFS) and metastasis-free survival (MFS).

RESULTS

The study comprised 372 patients, with 73 patients in each group after PSM. Compared with CRT, both STNT and LTNT demonstrated improved DFS (5-year rate: 59.7% vs. 77.8% vs. 76.5%, p = 0.027) and MFS (5-year rate: 65.1% vs. 81.3% vs. 81.4%, p = 0.030). There was no difference in DFS or MFS between STNT and LTNT. These favorable outcomes were consistent among subgroups defined by tumor distance from the anal verge ≥ 5 cm, clinical T3 stage, clinical N positive status, or involved mesorectal fascia.

CONCLUSION

Compared to CRT, both STNT and LTNT demonstrated improved DFS and MFS outcomes. Notably, survival outcomes were similar between STNT and LTNT, suggesting that chemotherapy cycles in TNT may not significantly impact survival.

Risk stratification of stage II rectal mucinous adenocarcinoma to predict the benefit of adjuvant chemotherapy following neoadjuvant chemoradiation and surgery

Background

The treatment strategy for stage II rectal mucinous adenocarcinoma (RMA) recommends neoadjuvant chemoradiotherapy (NCR) followed by total mesorectal excision (TME). However, the necessity of adjuvant chemotherapy (AC) remains controversial.

Materials and methods

Chi-square test was used to assess the relationship between pathological classification, AC and clinicopathological characteristics. Kaplan-Meier (KM) curves and the log-rank test were utilized to analyze differences in overall survival (OS) and cancer-specific survival (CSS) among different groups. Cox regression identified prognostic factors. Nomogram was established utilizing the independent prognostic factors. X-tile divided patients into three risk subgroups.

Results

Compared to RMA, rectal adenocarcinoma (RA) demonstrates longer OS and CSS in all and non-AC stage II patients, with no difference in OS and CSS for AC stage II patients. Propensity score matching analyses yielded similar results. Stratified analysis found that AC both improve OS of RA and RMA patients. Age, gender, pathologic T stage, regional nodes examined, and tumor size were identified as independent prognostic factors for RMA patients without AC. A nomogram was constructed to generate risk scores and categorize RMA patients into three subgroups based on these scores. KM curves revealed AC benefits for moderate and high-risk groups but not for the low-risk group. The external validation cohort yielded similar results.

Conclusions

In summary, our study suggests that, compared to stage II RA patients, stage II RMA patients benefit more from AC after NCR. AC is recommended for moderate and high-risk stage II RMA patients after NCR, whereas low-risk patients do not require AC.

Total Neoadjuvant Therapy (TNT) with Full Dose Concurrent Chemotherapy in Locally Advanced Rectal Adenocarcinoma Including Signet Ring and Mucinous Cancers

PURPOSE

Total neoadjuvant therapy (TNT) with pre-operative chemotherapy and chemoradiotherapy results in improved survival and is becoming the new standard of care in locally advanced rectal cancer (LARC). We describe our experience with TNT consisting of induction chemotherapy followed by chemoradiotherapy using full dose 5FU without oxaliplatin.

METHODS

Adults with biopsy-proven, newly diagnosed LARC with high-risk characteristics on pelvic MRI (T4a or T4b, extramural vascular invasion, N2, mesorectal fascia involvement, enlargement/tumor deposits on lateral lymph nodes) were included. The TNT protocol comprised of six biweekly courses of modified FOLFOX6 followed by pelvic RT with four concurrent cycles of biweekly 5-FU 2600 mg/m2 + LV 200 mg/m2 without oxaliplatin to complete 20 uninterrupted weeks of full dose 5FU. Surgery was planned 11-13 weeks after completing chemoradiotherapy.

RESULTS

Eighty-four LARC patients, including 26% with signet-ring cell carcinoma, with high-risk MRI characteristics were treated with the TNT protocol with a 96% completion rate. Significant (> grade 3) toxicities included neutropenia (23.8%), diarrhea (14.2%) anemia (10.7%), and two deaths. The median DFS at 2 years was 22.5 months with better survival noted for those who underwent surgery or had cCR (with NOM) compared to those who did not undergo surgery (due to progression, inadequate regression, or patient preference despite residual disease) -mDFS 27.7 months versus 11.4 months, p =  < 0.0001 and mOS 29.2 months versus 15 months p =  < 0.0001.

CONCLUSION

The hybrid TNT regimen was administered without significant dose delays or interruptions. Toxicity was manageable but with two treatment-related deaths. Ability to undergo surgery after TNT predicted for improved DFS and OS.

The role of adjuvant chemotherapy in rectal cancer patients with ypT0-2N0 after neoadjuvant chemoradiotherapy

Background

Neoadjuvant chemoradiotherapy has emerged as the established treatment for locally advanced rectal cancer. Nevertheless, there remains a debate regarding the necessity of adjuvant chemotherapy for patients with locally advanced rectal cancer who exhibit a favorable tumor response (ypT0-2N0) after neoadjuvant chemoradiotherapy and surgery. Thus, the objective of this study is to investigate the impact of adjuvant chemotherapy on the oncological prognosis of rectal cancer patients who have a good response to neoadjuvant chemoradiotherapy.

Materials and methods

The study was conducted following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses protocol. Articles were searched in the Web of Science, PubMed, and Cochrane Library databases. The primary outcomes assessed were 5-year overall survival, disease-free survival, cancer-specific survival, recurrence-free survival, local recurrence, and distant metastasis. The data was summarized using a random effects model.

Results

A meta-analysis was conducted using 18 retrospective studies published between 2009 and 2023. The studies included 9 from China and 5 from Korea, involving a total of 6566 patients with ypT0-2N0 rectal cancer after neoadjuvant chemoradiotherapy. The pooled data revealed that adjuvant chemotherapy significantly improved 5-year overall survival (OR=1.75, 95% CI: 1.15-2.65, P=0.008), recurrence-free survival (OR=1.73, 95% CI: 1.20-2.48, P=0.003), and reduced distant metastasis (OR=0.68, 95% CI: 0.51-0.92, P=0.011). However, adjuvant chemotherapy did not have a significant effect on disease-free survival, cancer-specific survival, and local recurrence in ypT0-2N0 rectal cancer. Subgroup analysis indicated that adjuvant chemotherapy was beneficial in improving overall survival for ypT1-2N0 rectal cancer (OR=1.89, 95% CI: 1.13-3.19, P=0.003).

Conclusion

The findings of the meta-analysis suggest that adjuvant chemotherapy may provide benefits in terms of oncological outcomes for rectal cancer patients with ypT0-2N0 after neoadjuvant chemoradiotherapy and radical surgery. However, further prospective clinical studies are needed to confirm these findings.

Effect of adjuvant chemotherapy on the oncological outcome of rectal cancer patients with pathological complete response

BACKGROUND

Locally advanced rectal cancer is typically treated using a combination of neoadjuvant chemoradiotherapy and total mesorectal resection. While achieving pathological complete response following neoadjuvant chemoradiotherapy has been recognized as a positive prognostic factor in oncology, the necessity of adjuvant chemotherapy for locally advanced rectal cancer patients with pathological complete response after surgery remains uncertain. The objective of this meta-analysis was to examine the impact of adjuvant chemotherapy on the oncological outcomes of rectal cancer patients who attain pathological complete response after neoadjuvant chemoradiotherapy.

METHODS

This meta-analysis followed the guidelines outlined in the preferred reporting items for systematic review and meta-analysis (PRISMA). The Web of Science, PubMed, and Cochrane Library databases were systematically searched to identify relevant literature.

RESULTS

A total of 34 retrospective studies, including 9 studies from the NCBD database, involving 31,558 patients with pathological complete response rectal cancer, were included in the meta-analysis. The included studies were published between 2008 and 2023. The pooled analysis demonstrated that adjuvant chemotherapy significantly improved overall survival (HR = 0.803, 95% CI 0.678-0.952, P = 0.011), and no heterogeneity was observed (I2 = 0%). Locally advanced rectal cancer patients with pathological complete response who underwent adjuvant chemotherapy exhibited a higher 5-year overall survival rate compared to those who did not receive adjuvant chemotherapy (OR = 1.605, 95% CI 1.183-2.177, P = 0.002). However, the analysis also revealed that postoperative ACT did not lead to improvements in disease-free survival and recurrence-free survival within the same patient population. Subgroup analysis indicated that pathological complete response patients with clinical stage T3/T4, lymph node positivity, and younger than 70 years of age may benefit from adjuvant chemotherapy in terms of overall survival.

CONCLUSIONS

The findings of this meta-analysis suggest that adjuvant chemotherapy has a beneficial effect on improving overall survival among rectal cancer patients with pathological complete response. However, no such association was observed in terms of disease-free survival and recurrence-free survival.

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

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

Adjuvant chemotherapy in patients with clinically node-negative but pathologically node-positive rectal cancer in the Netherlands: A retrospective analysis

INTRODUCTION

Accurate clinical staging of rectal cancer is hampered by suboptimal sensitivity of MRI in the detection of regional lymph node metastases. Consequently, some patients may be understaged and have been withheld neoadjuvant (chemo)radiotherapy in retrospect. Although Dutch guidelines do not advocate adjuvant chemotherapy (ACT) in rectal cancer, some of these clinically understaged patients receive ACT according to local policy. We aim to assess the benefit of ACT in these patients.

METHODS

Population-based data from patients with clinically node-negative (cN0) but pathologically node-positive (pN+) rectal cancer that underwent total mesorectal excision (TME) without neoadjuvant treatment between 2008 and 2018 were obtained from the Netherlands Cancer Registry. Missing data were handled by multiple imputation. Stabilised inverse probability treatment weighting (sIPTW) was used to balance clinical characteristics. Overall survival (OS) was compared in ACT and non-ACT patients.

RESULTS

Of 34,724 patients, 13,861 had cN0 disease of whom 3016 were pN+ (21.8%). 1466 (48.6%) of these patients underwent upfront TME and were included. Median follow-up was 84 months (95% confidence interval [CI] 76-97) versus 79 months (95% CI 77-81) in patients that did (n = 290, 19.8%) and did not (n = 1176, 80.2%) receive ACT, respectively. After sIPTW adjustment, ACT was associated with improved OS (hazard ratio 0.70; 95% CI 0.49-0.99; p = 0.04). The estimated 5-year OS rate was 74.2% versus 65.3%, respectively.

CONCLUSION

In this population-based cohort of patients with cN0 but pN+ rectal cancer who underwent upfront TME, ACT was associated with a significant OS benefit. These data support to discuss ACT in this population.

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.

Practice-changing clinical trials in radiation oncology for gastrointestinal malignancies in 2021-2023

Gastrointestinal cancers are one of the most frequent cancers and a leading cause of cancer deaths worldwide. We provide an overview of the most important practice-changing trials that were either published or presented at the international scientific meetings in 2021-2023. Highlights included reports on three phase III trials (CONCORDE/PRODIGE 26, ARTDECO, and a study by Xu et al.) that evaluated dose escalation in the definitive setting for locally advanced oesophageal cancers, as well as two phase III trials that evaluated the role of chemotherapy (neo-AEGIS) and targeted therapy (NRG/RTOG 1010) in the neoadjuvant setting for adenocarcinoma oesophageal cancers or gastroesophageal junction cancer. CheckMate 577 evaluated nivolumab in patients who had residual pathological disease after neoadjuvant chemoradiation followed by complete resection. The use of radiation therapy for borderline and locally advanced pancreatic cancer is also discussed (SMART and CONKO-007 trials). Stereotactic body radiation therapy followed by sorafenib was compared to sorafenib alone in patients with hepatocellular carcinoma in the NRG/RTOG 1112 study. New options in the management of rectal cancer are emerging such as total neoadjuvant treatment (PRODIGE 23, RAPIDO, PROSPECT), organ preservation (OPRA, OPERA), and the role of immunotherapy in patients with DNA mismatch-repair deficient/microsatellite instability. Finally, preliminary results of the ACT 4 trial that evaluated de-escalation in anal cancer are presented.

Improving prognosis and assessing adjuvant chemotherapy benefit in locally advanced rectal cancer with deep learning for MRI: A retrospective, multi-cohort study

PURPOSE

Adjuvant therapy is recommended to minimize the risk of distant metastasis (DM) and local recurrence (LR) in patients with locally advanced rectal cancer (LARC). However, its role is controversial. We aimed to develop a pretreatment MRI-based deep learning model to predict LR, DM, and overall survival (OS) over 5 years after surgery and to identify patients benefitting from adjuvant chemotherapy (AC).

MATERIALS AND METHODS

The multi-survival tasks network (MuST) model was developed in a primary cohort (n = 308) and validated using two external cohorts (n = 247, 245). An AC decision tree integrating the MuST-DM score, perineural invasion (PNI), and preoperative carbohydrate antigen 19-9 (CA19-9) was constructed to assess chemotherapy benefits and aid personalized treatment of patients. We also quantified the prognostic improvement of the decision tree.

RESULTS

The MuST network demonstrated high prognostic accuracy in the primary and two external cohorts for the prediction of three different survival tasks. Within the stratified analysis and decision tree, patients with CA19-9 levels > 37 U/mL and high MuST-DM scores exhibited favorable chemotherapy efficacy. Similar results were observed in PNI-positive patients with low MuST-DM scores. PNI-negative patients with low MuST-DM scores exhibited poor chemotherapy efficacy. Based on the decision tree, 14 additional patients benefiting from AC and 391 patients who received over-treatment were identified in this retrospective study.

CONCLUSION

The MuST model accurately and non-invasively predicted OS, DM, and LR. A specific and direct tool linking chemotherapy decisions and benefit quantification has also been provided.

Use of patient-derived tumor organoid platform to predict the benefit of postoperative adjuvant chemotherapy for poor responders to neoadjuvant chemoradiotherapy in locally advanced rectal cancer

Postoperative adjuvant chemotherapy (AC) for poor responders to neoadjuvant chemoradiotherapy (nCRT) remains debatable among patients with locally advanced rectal cancer (LARC), necessitating biomarkers to accurately predict the benefits of AC. This study aimed to develop a patient-derived tumor organoid (PDTO) platform to predict the benefit of AC in LARC patients showing poor nCRT response. PDTOs were established using irradiated rectal cancer specimens with poor nCRT responses, and their sensitivity to chemotherapy regimens was tested. The half-maximal inhibitory concentration (IC50) value for the PDTO drug test was defined based on the clinical outcomes, and the accuracy of the PDTO prognostic predictions was calculated. Predictive models were developed and validated using the PDTO drug test results. Between October 2018 and December 2021, 86 PDTOs were successfully constructed from 138 specimens (success rate 62.3%). The optimal IC50 cut-off value for the organoid drug test was 39.31 μmol/L, with a sensitivity of 84.75%, a specificity of 85.19%, and an accuracy of 84.88%. Multivariate Cox regression analysis revealed that the PDTO drug test was an independent predictor of prognosis. A nomogram based on the PDTO drug test was developed, showing good prognostic ability in predicting the 2-year and 3-year disease-free survivals (AUC of 0.826 [95% CI, 0.721-0.931] and 0.902 [95% CI, 0.823-0.982], respectively) and overall survivals (AUC of 0.859 [95% CI, 0.745-0.973] and 0.885 [95% CI, 0.792-0.978], respectively). The PDTO drug test can predict the benefit of postoperative AC in poor responders with LARC to nCRT.

Phase II study of capecitabine-based concomitant chemoradiation followed by durvalumab as a neoadjuvant strategy in locally advanced rectal cancer: the PANDORA trial

BACKGROUND

This study investigated the efficacy of chemoradiotherapy (CRT) followed by durvalumab as neoadjuvant therapy of locally advanced rectal cancer.

PATIENTS AND METHODS

The PANDORA trial is a prospective, phase II, open-label, single-arm, multicenter study aimed at evaluating the efficacy and safety of preoperative treatment with durvalumab (1500 mg every 4 weeks for three administrations) following long-course radiotherapy (RT) plus concomitant capecitabine (5040 cGy RT in 25-28 fractions over 5 weeks and capecitabine administered at 825 mg/m2 twice daily). The primary endpoint was the pathological complete response (pCR) rate; secondary endpoints were the proportion of clinical complete remissions and safety. The sample size was estimated assuming a null pCR proportion of 0.15 and an alternative pCR proportion of 0.30 (α = 0.05, power = 0.80). The proposed treatment could be considered promising if ≥13 pCRs were observed in 55 patients (EudraCT: 2018-004758-39; NCT04083365).

RESULTS

Between November 2019 and August 2021, 60 patients were accrued, of which 55 were assessable for the study's objectives. Two patients experienced disease progression during treatment. Nineteen out of 55 eligible patients achieved a pCR (34.5%, 95% confidence interval 22.2% to 48.6%). Regarding toxicity related to durvalumab, grade 3 adverse events (AEs) occurred in four patients (7.3%) (diarrhea, skin toxicity, transaminase increase, lipase increase, and pancolitis). Grade 4 toxicity was not observed. In 20 patients (36.4%), grade 1-2 AEs related to durvalumab were observed. The most common were endocrine toxicity (hyper/hypothyroidism), dermatologic toxicity (skin rash), and gastrointestinal toxicity (transaminase increase, nausea, diarrhea, constipation).

CONCLUSION

This study met its primary endpoint showing that CRT followed by durvalumab could increase pCR with a safe toxicity profile. This combination is a promising, feasible strategy worthy of further investigation.

Adjuvant chemotherapy in locally advanced rectal cancer after neo-adjuvant concurrent chemoradiotherapy and surgery: A retrospective study in Vietnamese patients

Background

Advances in preoperative chemoradiotherapy and surgical techniques offered improvements in rates of locoregional recurrence but did not address distant metastasis. Traditionally, adjuvant chemotherapy has been administered with the goal of limiting systemic recurrences.

Objective

Evaluation of the efficacy and safety of adjuvant chemotherapy in patients with locally advanced rectal cancer after preoperative chemoradiotherapy and surgery.

Methods

From January 2017 to December 2018, 103 patients diagnosed with clinical stage II or III rectal cancer received adjuvant chemotherapy with capecitabine or XELOX regimens after neoadjuvant concurrent chemoradiotherapy and total mesorectal excision. Overall survival, disease-free survival, and toxicity were analyzed.

Results

The median follow-up time was 52.5 months (6.5-66.8 months). The mean 3-year disease-free survival and 3-year overall survival were 86.2% (95% CI: 82.8-89.6) and 92.2% (95% CI: 86.9-97.5), respectively. The rate of hematologic and nonhematologic toxicity was low, mostly grades 1 and 2 including anemia, leucopenia, thrombocytopenia, and liver enzymes elevations were 85.4, 50.5, 42.8, and 45.6%, respectively.

Conclusion

The capecitabine and XELOX regimen in adjuvant settings for rectal cancer patients receiving neoadjuvant chemoradiotherapy and surgery was a safe and effective modality. Further randomized trials need to be conducted to evaluate the role of postoperative therapy for these individuals.

Neoadjuvant anti-PD-1/PD-L1 therapy for colorectal cancer: Current status and future prospects

Immunotherapy, particularly programmed cell death 1/programmed cell death ligand 1 (PD-1/PD-L1) inhibitors, has made revolutionary progress in the treatment strategies for various types of cancer. Regarding colorectal cancer (CRC), the current clinical application of PD-1/PD-L1 inhibitors is primarily categorized based on mutation patterns, including deficient mismatch repair (dMMR)/high microsatellite instability (MSI-H) and proficient mismatch repair (pMMR) or non-high microsatellite instability (non-MSI-H). PD-1/PD-L1 inhibitors have demonstrated good efficacy against dMMR/MSI-H CRC by increasing T-cell infiltration into tumor tissues. However, the effectiveness of PD-1/PD-L1 inhibitors for pMMR/non-MSI-H CRC remains uncertain. Due to the lower prevalence of dMMR/MSI-H in CRC, recent clinical trials have reported combined applications of PD-1/PD-L1 inhibitors with other anti-tumor treatments such as chemotherapy, radiotherapy, and targeted therapy to achieve better therapeutic outcomes. Neoadjuvant therapy, primarily consisting of chemotherapy and radiotherapy, not only downstages the tumor but also provides benefits from local control, thus improving clinical symptoms and quality of life. Integrating immunotherapy into neoadjuvant therapy may alter the treatment approach for potentially resectable or certain metastatic CRC cases. In this article, we focus on the development of neoadjuvant anti-PD-1/PD-L1 therapy and discuss its future prospects for the treatment of CRC.

Total Neoadjuvant Treatment for Locally Advanced Rectal Cancer Patients: Where Do We Stand?

The therapeutic landscape in locally advanced rectal cancer (LARC) has undergone a significant paradigm shift in recent years with the rising adoption of total neoadjuvant treatment (TNT). This comprehensive approach entails administering chemotherapy and radiation therapy before surgery, followed by optional adjuvant chemotherapy. To establish and deliver the optimal tailored treatment regimen to the patient, it is crucial to foster collaboration among a multidisciplinary team comprising healthcare professionals from various specialties, including medical oncology, radiation oncology, surgical oncology, radiology, and pathology. This review aims to provide insights into the current state of TNT for LARC and new emerging strategies to identify potential directions for future research and clinical practice, such as circulating tumor-DNA, immunotherapy in mismatch-repair-deficient tumors, and nonoperative management.

Improved Survival After Adjuvant Therapy in Locally Advanced Rectal Cancer Patients With Pathologic Complete Response

BACKGROUND

The benefit of adjuvant therapy is unclear in patients with rectal cancer achieving a pathologic complete response after neoadjuvant chemoradiotherapy and total mesorectal excision.

OBJECTIVE

This study aimed to assess the benefit of adjuvant chemotherapy on survival among rectal cancer patients with a pathologic complete response after neoadjuvant chemoradiation.

DESIGN

Retrospective cohort study.

SETTING

National Cancer Database (2004-2017).

PATIENTS

Patients with clinical stage 2 or 3 rectal adenocarcinoma who underwent neoadjuvant chemoradiation (50-50.4 Gy in 25-28 fractions) followed by total mesorectal excision with a pathologic complete response were included.

INTERVENTION

Adjuvant chemotherapy.

MAIN OUTCOME MEASURES

Overall survival.

RESULTS

There were 20,518 patients and 2221 (11%) had a pathologic complete response after neoadjuvant chemoradiation. Of 2221 patients, 1441 (65%) did not receive adjuvant therapy and 780 (35%) did. Patients who received adjuvant therapy were more likely to be younger (median 58 vs 62 y), have private insurance (61% vs 49%), and have node-positive disease (57% vs 48%) (all p < 0.05). There were no differences in sex, race, Charlson-Deyo score, clinical T-stage, tumor size and differentiation, adequate lymphadenectomy (12 or more), or sphincter preservation between groups (all p > 0.05). Overall survival at 5, 10, and 14 years was significantly longer in the adjuvant group (93%, 85%, 83%, respectively) compared to patients who did not receive adjuvant therapy (87%, 67%, 51%, respectively) ( p < 0.001). In a subgroup analysis, adjuvant therapy was associated with improved survival in patients with clinical stage 2 and 3 rectal cancer ( p < 0.001). After adjusting for patient and tumor characteristics, omission of adjuvant chemotherapy was associated with significantly worse survival (HR 1.53, 95% 1.08-2.16).

LIMITATIONS

Selection bias, unknown perioperative morbidity, chemotherapy regimen, recurrence status, and other unidentified factors limiting survival analysis.

CONCLUSIONS

In patients with clinical stage 2 or 3 rectal cancer, adjuvant chemotherapy was associated with improved overall survival in patients achieving a pathological complete response after neoadjuvant chemoradiotherapy. See Video Abstract at http://links.lww.com/DCR/C139 .

SOBREVIDA MEJORADA DESPUS DE LA TERAPIA ADYUVANTE EN PACIENTES CON CNCER DE RECTO LOCALMENTE AVANZADO CON RESPUESTA PATOLGICA COMPLETA

ANTECEDENTES:En los pacientes con cáncer de recto que logran una respuesta patológica completa después de la quimiorradioterapia neoadyuvante y la escisión total del mesorrecto, el beneficio de la terapia adyuvante no está claro.OBJETIVO:Evaluar el beneficio de la quimioterapia adyuvante en la sobrevida de los pacientes con cáncer de recto con una respuesta patológica completa después de la quimiorradioterapia neoadyuvante.DISEÑO:Estudio de cohorte retrospectivo.ESCENARIO:Base de Datos Nacional de Cáncer (2004-2017).PACIENTES:Pacientes con adenocarcinoma rectal en estadio clínico 2 ó 3 que se sometieron a quimiorradiación neoadyuvante (50-50,4 Gy en 25-28 fracciones) seguida de escisión mesorrectal total con una respuesta patológica completa.INTERVENCIÓN:Quimioterapia adyuvante.PRINCIPALES MEDIDAS DE RESULTADO:Sobrevida global.RESULTADOS:Hubo 20.518 pacientes y 2.221 (11%) tuvieron una respuesta patológica completa después de la quimiorradiación neoadyuvante. Entre estos 2221 pacientes, 1441 (65%) no recibieron terapia adyuvante y 780 (35%) sí. Los pacientes que recibieron terapia adyuvante tenían más probabilidades de ser más jóvenes (mediana de 58 frente a 62 años), tener un seguro privado (61% frente a 49%) y tener enfermedad con linfonodos positivos (57% frente a 48 %) (todos p < 0,05). No hubo diferencias en género, raza, puntuación de Charlson-Deyo, estadio T clínico, tamaño y diferenciación del tumor, linfadenectomía adecuada (≥12) o preservación del esfínter entre los grupos (todos p > 0,05). La sobrevida general a los 5, 10 y 14 años fue significativamente mayor en el grupo adyuvante (93%, 85%, 83%, respectivamente) en comparación con los pacientes que no recibieron terapia adyuvante (87%, 67%, 51% respectivamente) ( p < 0,001). En un análisis de subgrupos, la terapia adyuvante se asoció con una mejor sobrevida general en pacientes con cáncer de recto en estadio clínico 2 y 3 ( p < 0,001). Después de ajustar por las características del paciente y del tumor, la omisión de la quimioterapia adyuvante se asoció con una sobrevida global significativamente peor (HR 1,53, IC del 95%, 1,08-2,16).LIMITACIONES:Sesgo de selección; morbilidad perioperatoria desconocida, régimen de quimioterapia, estado de recurrencia y otros factores no identificados que limitan el análisis de sobrevida.CONCLUSIONES:En pacientes con cáncer de recto en estadio clínico 2 ó 3, la quimioterapia adyuvante se asoció con una mejor sobrevida general en pacientes que lograron una respuesta patológica completa después de la quimiorradioterapia neoadyuvante. Consulte Video Resumen en http://links.lww.com/DCR/C139 . (Traducción-Dr. Felipe Bellolio ).

Circulating tumor DNA detection after neoadjuvant treatment and surgery predicts recurrence in patients with early-stage and locally advanced rectal cancer

INTRODUCTION

Patients with early-stage and locally advanced rectal cancer are often treated with neoadjuvant therapy followed by surgery or watch and wait. This study evaluated the role of circulating tumor DNA (ctDNA) to measure disease after neoadjuvant treatment and surgery to optimize treatment choices.

MATERIALS AND METHODS

Patients with rectal cancer treated with both chemotherapy and radiotherapy were included and diagnostic biopsies were analyzed for tumor-specific mutations. Presence of ctDNA was measured in plasma by tracing the tumor-informed mutations using a next-generation sequencing panel. The association between ctDNA detection and clinicopathological characteristics and progression-free survival was measured.

RESULTS

Before treatment ctDNA was detected in 69% (35/51) of patients. After neoadjuvant therapy ctDNA was detected in only 15% (5/34) of patients. In none of the patients with a complete clinical response who were selected for a watch and wait strategy (0/10) or patients with ypN0 disease (0/8) ctDNA was detected, whereas it was detected in 31% (5/16) of patients with ypN + disease. After surgery ctDNA was detected in 16% (3/19) of patients, of which all (3/3) developed recurrent disease compared to only 13% (2/16) in patients with undetected ctDNA after surgery. In an exploratory survival analysis, both ctDNA detection after neoadjuvant therapy and after surgery was associated with worse progression-free survival (p = 0.01 and p = 0.007, respectively, Cox-regression).

CONCLUSION

These data show that in patients with early-stage and locally advanced rectal cancer tumor-informed ctDNA detection in plasma using ultradeep sequencing may have clinical value to complement response prediction after neoadjuvant therapy and surgery.

The Conditioning of Adjuvant Chemotherapy for Stage II and III Rectal Cancer Determined by Postoperative Pathological Characteristics in Romania

The management of locally advanced rectal cancer (LARC) suffered changes thanks to the development of improved surgical procedures, radiation delivery, and chemotherapy. Although treatment options improved individually, the optimal order is still debated. Neoadjuvant chemo-radiotherapy followed by total mesorectal excision (TME) has been the "golden standard" for locally advanced rectal cancer. There is no common ground in international guidelines on the indications of adjuvant chemotherapy (ADJCHT), with differences between the American, European, and Japanese guidelines. This paper studies the preferences of Romanian oncologists in prescribing ADJCHT. We conducted a single-institution, retrospective study of all nonmetastatic, ECOG 0-1 LARC patients staged II-III who underwent TME and were admitted to the Oncology or Radiotherapy Department of Colțea Clinical Hospital, Bucharest between January 2017 and March 2021. A total of 186 patients were included in the study. A positive correlation was found between ADJCHT and each of the following: (y)pT > 2, (y)pN > 0, and the presence of perineural invasion (PNI+). A strong positive correlation was found between ADJCHT and the presence of at least one risk factor: (y)pT > 2, (y)pN > 0, PNI+, lymphovascular invasion, positive margins, or tumor grade > 1. Tumor downstaging decreased the risk of metastases in the first 2 years and was associated with the use of neoadjuvant radiotherapy, while adding neoadjuvant chemotherapy increased the chance of nodal downstaging. ADJCHT practice for LARC in Romania follows either NCCN or ESMO guidelines, at the discretion of the oncologist, due to the lack of national guideline.

Early closure compared to late closure of temporary ileostomy in rectal cancer: a randomized controlled trial study

BACKGROUND

A temporary loop ileostomy is one of the most common methods for the prevention of anastomotic leakage in rectal cancer patients who underwent low anterior resection. However, the optimal timing of loop ileostomy reversal remains unknown. The main objective of this study was to evaluate the debilitating complications caused by early closure of ileostomy in comparison with late closure in rectal cancer patients.

DESIGN

A randomized, controlled, unblinded, and monocentric trial.

METHODS

A total of 104 rectal cancer patients were randomly assigned to the case group of early closure of ileostomy (n = 50) and the control group of late closure of ileostomy (n = 54). This trial was undertaken in a single colorectal institution, a university-affiliated teaching hospital in Tehran, Iran. Randomization and allocation to the trial group were conducted by using variable block randomization based on quadruple numbers. The primary endpoint of this trial was determined by the complications of early ileostomy closure versus those of late closure in rectal cancer patients who had undergone low anterior resection. In early closure, loop ileostomy is reversed 2-3 weeks after the first two courses of adjuvant chemotherapy, while in late closure, the ileostomy is reversed 2-3 weeks after the last course of adjuvant chemotherapy.

RESULTS

Follow-up of 1 year demonstrated a reduction in the risk of complications and an improved quality of life in patients with rectal cancer following low anterior resection and chemotherapy (neoadjuvant and adjuvant) in the case group but did not reach a significant difference (p = 0.555). In addition, there was no significant difference in perioperative outcomes, such as blood loss, operative time, readmission, and reoperation; also, no statistically significant differences were reported between the groups in patients' quality of life or LARS score.

CONCLUSION

In summary, it seems that early closure of ileostomy is not better than late closure in improving patients' quality of life with rectal cancer following low anterior resection and chemotherapy (neoadjuvant and adjuvant); no statistical difference was observed for reduction of risk of ostomy complications. Thus, neither of these methods (early closure versus late closure) is superior to the other, and controversy still exists.

TRIAL REGISTRATION NUMBER AND DATE OF REGISTRATION

IRCT20201113049373N1.

Total neoadjuvant therapy versus chemoradiotherapy for locally advanced rectal cancer: Bayesian network meta-analysis

BACKGROUND

Total neoadjuvant therapy is a promising treatment for locally advanced rectal cancer, utilizing either short-course radiotherapy or long-course chemoradiotherapy, but their relative efficacy remains unclear. The aim of this Bayesian network meta-analysis was to investigate clinical outcomes amongst patients receiving total neoadjuvant therapy with short-course radiotherapy or long-course chemoradiotherapy, and those receiving long-course chemoradiotherapy alone.

METHODS

A systematic literature search was performed. All studies that compared at least two of these three treatments for locally advanced rectal cancer were included. The primary endpoint was the pathological complete response rate, and survival outcomes were adopted as secondary outcomes.

RESULTS

Thirty cohorts were included. Compared with long-course chemoradiotherapy, both total neoadjuvant therapy with long-course chemoradiotherapy (OR 1.78, 95 per cent c.i. 1.43 to 2.26) and total neoadjuvant therapy with short-course radiotherapy (OR 1.75, 95 per cent c.i. 1.23 to 2.50) improved the pathological complete response rate. Similar benefits were observed in the sensitivity and subgroup analyses, except for short-course radiotherapy with one to two cycles of chemotherapy. No significant differences in survival outcomes were found amongst the three treatments. Long-course chemoradiotherapy with consolidation chemotherapy (HR 0.44, 95 per cent c.i. 0.20 to 0.99) exhibited higher disease-free survival than long-course chemoradiotherapy alone.

CONCLUSION

Compared with long-course chemoradiotherapy, both short-course radiotherapy with greater than or equal to three cycles of chemotherapy and total neoadjuvant therapy with long-course chemoradiotherapy can improve the pathological complete response rate, and long-course chemoradiotherapy with consolidation chemotherapy may lead to a marginal benefit in disease-free survival. The pathological complete response rate and survival outcomes are similar for total neoadjuvant therapy with short-course radiotherapy or long-course chemoradiotherapy.

Adjuvant chemotherapy does not improve cancer-specific survival for pathologic stage II/III rectal adenocarcinoma after neoadjuvant chemoradiotherapy and surgery: evidence based on long-term survival analysis from SEER data

PURPOSE

Adjuvant chemotherapy is controversial in rectal cancer, especially after neoadjuvant chemoradiotherapy (NCRT). This retrospective study aims at evaluating adjuvant chemotherapy's long-term survival benefits in stage II and stage III rectal adenocarcinoma (RC).

METHODS

This study obtained data from the Surveillance, Epidemiology, and End Results (SEER) database registered between 2010 and 2015. The survival analyses used the Kaplan-Meier method and were compared by log-rank test. The factors that affect survival outcomes were analyzed by univariate and multivariate Cox regression. The propensity score matching (1:4) was used to ensure the balance of variables between different groups.

RESULTS

The median follow-up time for overall patients was 64 months. The 5-year overall survival (OS) and cancer-specific survival (CSS) rates were 51.3% and 67.4% in the adjuvant chemotherapy (-) group and 73.9% and 79.6% in the adjuvant chemotherapy ( +) group (p < 0.001, p = 0.002). However, subgroup analysis showed adjuvant chemotherapy after NCRT improved the 5-year OS but not CSS rates in stage II and stage III RC (p = 0.003, p = 0.004; p = 0.29, p = 0.3). Univariate and multivariate analyses found adjuvant chemotherapy after NCRT was an independent prognosis factor of OS but not CSS (HR 0.8, 95%CI 0.7-0.92, p < 0.001; p = 0.276).

CONCLUSION

The survival benefits from adjuvant chemotherapy were associated with the status of NCRT for pathological stage II and III RC. For patients who did not receive NCRT, adjuvant chemotherapy is needed to significantly improve long-term survival rates. However, adjuvant chemotherapy after NCRT did not significantly improve long-term CSS.

Current status of locally advanced rectal cancer therapy and future prospects

Rectal cancer treatment has been evolving ever since the beginning of the 20th century. Surgery was originally the only available method regardless of the extent of tumor invasion or nodal involvement status. Total mesorectal excision was established as the standard procedure in the early 1990s. Advances in the utilization of radiation for rectal cancer led to the addition of radiotherapy (RT) combined with chemotherapy to the postoperative treatment algorithm. The promising results of the Swedish short-course preoperative RT set the basis for a number of large randomized trials investigating the efficacy of neoadjuvant RT or chemoradiotherapy (CRT) for advanced rectal cancer. Both short-course RT and long-course preoperative CRT compared favorably to adjuvant treatment and became the standard of choice for patients with extramural invasion or lymph node involvement. Recently, the focus of clinical research has been shifted towards total neoadjuvant therapy (TNT), delivering the whole course of RT and chemotherapy before surgery, and showing good tolerance and encouraging efficacy. Although targeted therapies haven't displayed a benefit in the neoadjuvant setting, preliminary evidence suggests impressive efficacy of immunotherapy in rectal carcinomas with mismatch-repair deficiency. In this review, we provide an in-depth critical overview of all significant randomized trials that have shaped the current treatment guidelines for locally advanced rectal cancer and discuss future trends for the treatment of this common malignancy.

Efficacy and safety of total neoadjuvant therapy in locally advanced rectal cancer: a meta-analysis

PURPOSE

The standard of care for locally advanced rectal cancer (LARC) has changed from a single radical surgical treatment to the current multimodality treatment (standard chemoradiotherapy (CRT) and total neoadjuvant therapy (TNT)). The efficacy and safety of both TNT and standard CRT are evaluated in randomized controlled trials (RCTs).

METHODS

RCTs were comprehensively searched in Chinese and English electronic databases. The experimental and control groups were TNT and the standard CRT, respectively, included in this meta-analysis. The outcomes were assessed through a fixed-effect or random-effect model of pooled odds (OR) or hazard ratios (HR).

RESULTS

Eleven RCTs, involving 3,101 patients were included in the final analysis. TNT showed increase in the pathological complete response (pCR) (OR = 1.95, 95% confidence interval (CI): 1.57-2.41; P < 0.05) and the R0 resection (OR = 1.19, 95% CI: 0.99-1.43; P = 0.062). There was no significant difference in local recurrence-free survival (LRFS) (HR = 0.97, P = 0.803), but TNT had better 3-year disease-free survival (DFS) (HR = 0.82, 95% CI: 0.72-0.93, P < 0.05), overall survival (OS) (HR = 0.87, 95% CI: 0.74-1.02, P = 0.08) and distant metastasis-free survival (DMFS) (HR = 0.79, 95% CI: 0.67-0.93, P < 0.05) than standard CRT.

CONCLUSIONS

TNT was safe and feasible as it improved pCR and survival outcomes, and reduced the risk of distant metastasis compared with standard CRT. TNT may be a superior strategy for LARC, but more RCTs are needed to prove it.

REGISTRATION AND PROTOCOL

PROSPERO CRD42022327697. We added the Chinese database after registration because of the inclusion of fewer RCTs www.crd.york.ac.uk/PROSPERO/ .

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

OBJECTIVE

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

BACKGROUND DATA

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Incidence and risk outcomes of second primary malignancy of patients with post-operative colorectal cancer

BACKGROUND AND AIMS

This study aimed to investigate the incidence and the risk factors of incidence for second primary malignancies (SPMs) onset among survivors diagnosed with colorectal cancer (CRC).

METHODS

A large population-based cohort study was performed. Data of patients diagnosed with CRC was identified and extracted from 8 cancer registries of Surveillance, Epidemiology, and End Results database from January 1990 to December 2017. The outcome of interest was percentage and common sites of SPM onset after primary CRC diagnosis. The cumulative incidence and standardize incidence rates (SIRs) were also reported. Afterwards, we estimated sub-distribution hazards ratios (SHRs) and relative risks (RRs) for SPM occurrence using multivariable competing-risk and Poisson regression models, respectively.

RESULTS

A total of 152,402 patients with CRC were included to analyze. Overall, 23,816 patients of all CRC survivors (15.6%) were reported SPM occurrence. The highest proportion of SPMs development after primary CRC diagnosis was second CRC, followed by lung and bronchus cancer among all survivors. Also, CRC survivors were more susceptible to develop second gastrointestinal cancers (GICs). Besides, pelvic cancers were analyzed with a relative high proportion among patients who received RT in comparison to those without RT. The cumulative incidence of all SPMs onset was 22.16% (95% CI: 21.82-22.49%) after near 30-year follow-up. Several factors including older age, male, married status, and localized stage of CRC were related to the high risk of SPMs onset. In treatment-specific analyses, RT was related to a higher cumulative incidence of SPMs occurrence (all SPMs: 14.08% vs. 8.72%; GICs: 2.67% vs. 2.04%; CRC: 1.01% vs. 1.57%; all p < 0.01). Furthermore, the increased risk of SPMs onset was found among patients who received RT than patients within the NRT group (SHR: 1.50, 95% CI: 1.32-1.71), p < 0.01; RR: 1.61, 95% CI: 1.45-1.79, p < 0.01).

CONCLUSION

The present study described the incidence pattern of SPM among CRC survivors and identified the risk factors of the SPM onset. RT treatment for patients diagnosed with CRC may increase the risk of SPMs occurrence. The findings suggest the need for long-term follow-up surveillance for these patients.

A systematic review and network meta-analysis of randomised controlled trials comparing neoadjuvant treatment strategies for stage II and III rectal cancer

AIM

Multiple neoadjuvant therapy strategies have been used and compared for rectal cancer and there has been no true consensus as to the optimal neoadjuvant therapy regimen. The aim is to identify and compare the neoadjuvant therapies available for stage II and III rectal cancer.

DESIGN

A systematic literature review was performed, from inception to August 2022, of the following databases: MEDLINE, EMBASE, Science Citation Index Expanded, Cochrane Library. Only randomized controlled trials comparing neoadjuvant therapies for stage II and III rectal cancer were considered. Stata was used to draw network plots, and a Bayesian network meta-analysis was conducted through models utilizing the Markov Chain Monte Carlo method in WinBUGS.

RESULTS

A total of 58 articles were included based on 41 randomised controlled trials, reporting on 12,404 participants that underwent 15 neoadjuvant treatment regimens. No significant difference was identified between treatments for major or total postoperative complications, anastomotic leak rates, or sphincter-saving surgery. Straight to surgery (STS) ranked as best treatment for preoperative toxicity but ranked worst treatment for positive resection margins and complete response. STS had significantly increased positive resection margins compared to long-course chemoradiotherapy with short-wait (LCCRT-SW) or long-wait (LCCRT-LW) to surgery, or short-course radiotherapy with short-wait (SCRT-SW) or immediate surgery (SCRT-IS). LCCRT-SW or LCCRT-LW resulted in significantly increased complete response rates compared to STS. LCCRT-LW significantly improved 2-year overall survival compared to STS, SCRT-IS, SCRT-SW. Total neoadjuvant therapy regimes with short-course radiotherapy followed by consolidation chemotherapy (SCRT-CT-SW), induction chemotherapy followed by long-course chemoradiotherapy (CT-LCCRT-S), long-course chemoradiotherapy followed by consolidation chemotherapy (LCCRT-CT-S), significantly improved positive resection margins, complete response, and disease-free survival compared to STS. Chemotherapy with monoclonal antibodies followed by long-course chemoradiotherapy (CT+MAB-LCCRT+MAB-S) significantly improved complete response and positive resection margins compared to STS, and 2-year disease-free survival compared to STS, SCRT-IS, SCRT-SW, SCRT-CT-SW, LCCRT-SW, LCCRT-LW. CT+MAB-LCCRT+MAB-S ranked as best treatment for disease-free survival and overall survival.

CONCLUSIONS

Conventional neoadjuvant therapies with short-course radiation or long-course chemoradiotherapy have oncological benefits compared to no neoadjuvant therapy without increasing perioperative complication rates. Prolonged wait to surgery may improve oncological outcomes. Total neoadjuvant therapies provide additional benefits in terms of complete response, positive resection margins, and disease-free survival. Monoclonal antibody therapy may further improve oncological outcomes but currently is only applicable to a small subgroup of patients and requires further validation.

The impact of adjuvant chemotherapy on survival in mucinous and non-mucinous rectal adenocarcinoma patients after TME surgery

INTRODUCTION

The value of adjuvant chemotherapy for rectal cancer patients is debated and varies in different subgroups. One such subgroup is mucinous adenocarcinoma (MAC), which is more treatment resistant compared to non-mucinous adenocarcinoma (NMAC). To date, mucinous histology is not taken into account when deciding on adjuvant treatment strategy. This is the first study to exclusively include patients with rectal cancer, then separate MAC and NMAC and compare the survival in patients that had or did not have adjuvant chemotherapy.

MATERIAL AND METHODS

The study included retrospective register data from 365 Swedish patients with stage II-IV rectal adenocarcinoma, 56 patients with MAC and 309 patients with NMAC. All patients were considered curative, had surgery with total mesorectal excision in 2004-2013, and were followed up until death or 2021.

RESULTS

Patients with MAC that had adjuvant chemotherapy had better overall survival (OS, HR 0.42; CI 95%: 0.19-0.93; p = 0.032) and a trend towards better cancer-specific survival (CSS, HR 0.41 CI 95%: 0.17-1.03; p = 0.057) compared to patients without chemotherapy (HR 0.42; CI 95%: 0.19-0.93; p = 0.032). The difference in OS was still significant even after adjusting for sex, age, stage, differentiation, neoadjuvant chemotherapy and preoperative radiotherapy (HR 0.40; CI 95%: 0.17-0.92; p = 0.031). There was no such difference in the NMAC patients except in the stage-by-stage subgroup analyses where patients in stage IV had better survival after adjuvant chemotherapy.

CONCLUSIONS

There may be a difference in treatment response to adjuvant chemotherapy between MAC and NMAC patients. Patients with MAC could possibly benefit from adjuvant chemotherapy in stages II-IV. Further studies are however needed to confirm these results.

Circulating tumour DNA as biomarker for rectal cancer: A systematic review and meta-analyses

Background

Circulating tumour DNA (ctDNA) has been established as a promising (prognostic) biomarker with the potential to personalise treatment in cancer patients. The objective of this systematic review is to provide an overview of the current literature and the future perspectives of ctDNA in non-metastatic rectal cancer.

Methods

A comprehensive search for studies published prior to the 4^th of October 2022 was conducted in Embase, Medline, Cochrane, Google scholar, and Web of Science. Only peer-reviewed original articles and ongoing clinical trials investigating the association between ctDNA and oncological outcomes in non-metastatic rectal cancer patients were included. Meta-analyses were performed to pool hazard ratios (HR) for recurrence-free survival (RFS).

Results

A total of 291 unique records were screened, of which 261 were original publications and 30 ongoing trials. Nineteen original publications were reviewed and discussed, of which seven provided sufficient data for meta-analyses on the association between the presence of post-treatment ctDNA and RFS. Results of the meta-analyses demonstrated that ctDNA analysis can be used to stratify patients into very high and low risk groups for recurrence, especially when detected after neoadjuvant treatment (HR for RFS: 9.3 [4.6 - 18.8]) and after surgery (HR for RFS: 15.5 [8.2 - 29.3]). Studies investigated different types of assays and used various techniques for the detection and quantification of ctDNA.

Conclusions

This literature overview and meta-analyses provide evidence for the strong association between ctDNA and recurrent disease. Future research should focus on the feasibility of ctDNA-guided treatment and follow-up strategies in rectal cancer. A blueprint for agreed-upon timing, preprocessing, and assay techniques is needed to empower adaptation of ctDNA into daily practice.

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

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

Chemotherapy Duration for Various Indications in Colorectal Cancer: a Review

PURPOSE OF REVIEW

The treatment of colorectal cancer (CRC) has evolved and become more personalized during the past several years. For example, depotentiation/reduced duration of systemic therapies has proven to be beneficial in both advanced and early stages of the disease.

RECENT FINDINGS

In particular, recent randomized studies of stage III and high-risk stage II CRC showed that a shorter duration (3 months), when compared to the historical 6-month comparator, provides nearly similar overall survival (OS) and disease-free survival (DFS). In the setting of advanced, inoperable CRC, a relatively short induction phase (six to eight cycles) followed by biological agents is the current standard of care in RAS wild-type (wt). versus RAS mutated cases. With regard to potentially operable stage IV disease (with the aim of converting liver metastases to operability), a relatively short number of cycles (four to six cycles) should be offered with re-staging and re-evaluation for surgery as soon as possible in most cases. For inoperable liver metastases, a relatively intensive triplet or doublet plus targeted therapy may attain conversion in some cases and may even result in cure. Rectal cancer treatment continues to be a complex disease in terms of treatment and oncological results. Recent data seem to showcase the benefits of more prolonged sequential strategies (total neoadjuvant therapy, all treatment delivered before surgery, to reduce the risk of distant metastases and local control). In recent years, different strategies regarding treatment intensity have been employed in CRC in adjuvant and metastatic setting. Introduction of triplets as first-line therapy for colon cancer and as induction phase for rectal cancer are now therapeutic options. Conversely in stage II disease or low-risk stage III resected CRC, a reduced chemotherapy length is a new standard of care.

An International Multicenter Prospective Study Evaluating the Long-term Oncological Impact of Adjuvant Chemotherapy in ypN+ Rectal Cancer

OBJECTIVE

To assess the oncological benefit of adjuvant chemotherapy (AC) in node positive (ypN+) rectal cancer after neoadjuvant chemoradiotherapy and radical surgery.

BACKGROUND

The evidence for AC after total mesorectal excision for locally advanced rectal cancer is conflicting and the net survival benefit is debated.

METHODS

An international multicenter comparative cohort study was performed comparing oncological outcomes in tertiary rectal cancer centers from the Netherlands and France. Patients with locally advanced rectal cancer treated with neoadjuvant chemoradiotherapy followed by total mesorectal excision surgery and with positive lymph nodes on histologic examination (ypN+) were included for analysis. Kaplan-Meier curves were generated to compare disease-free (DFS) and overall survival in AC and non-AC groups.

RESULTS

Of 1265 patients screened, a total of 239 rectal cancer patients with ypN+ disease were included. Demographic and clinical characteristics were similar in both groups. Higher systemic recurrence rates were observed in the non-AC group compared with those who received AC [32.0% (n=40) vs 17.5% (n=11), respectively, P =0.034]. DFS at 1 and 5 years postoperatively were significantly better in the AC group (92% vs 80% at 1 year; 72% vs 51% at 5 years, P =0.024), whereas no difference in overall survival was observed.

CONCLUSIONS

In this multicenter comparative cohort study, we identified an oncological benefit of AC in both systemic recurrence and DFS in ypN+ rectal cancer patients. From this data, systemic chemotherapy continues to confer oncological benefit in locally advanced ypN+ rectal cancer.

Is There a Role for Adjuvant Chemotherapy in Pathologic Node-Negative Locally Advanced Rectal Cancer After Neoadjuvant Chemoradiation Therapy?

BACKGROUND

Neoadjuvant chemoradiation therapy (NCRT, 5-fluorouracil and radiation) followed by resection and adjuvant chemotherapy (AC) is one of the standard treatment paradigms for locally advanced rectal adenocarcinoma. However, the utility of AC in patients with pathologic lymph node (pLN)-negative disease is unclear. Our aim is to assess the value of AC stratified by pLN status.

METHODS

The US Rectal Cancer Consortium database (2007-2017) was retrospectively reviewed for patients with clinical stage II and III rectal adenocarcinoma who received neoadjuvant chemoradiation (NACR) and curative-intent resection. Those who received neoadjuvant systemic chemotherapy or underwent local resection were excluded. Patients were categorized by pLN status. Primary outcome was overall survival (OS).

RESULTS

Of 213 patients, 70% had pLN-negative disease and 30% pLN-positive disease. Median age was 57 years, 65% were male, and median follow-up was 31 months. Among patients with pLN-negative disease, 74% received AC. Receipt of AC was not associated with improved 5-year OS (82% versus 74%, respectively; p = 0.16). This finding persisted on multivariable analysis. Of patients with pLN-positive disease, 83% received AC. Patients with pLN-positive disease demonstrated improved 5-year OS with receipt of AC (72% compared with 0% with no adjuvant chemotherapy, p = 0.04).

CONCLUSION

After receiving neoadjuvant chemoradiation, adjuvant chemotherapy for patients with pLN-negative disease does not appear to be associated with improved survival. Further validation and prospective studies are needed to evaluate the utility of adjuvant chemotherapy in this setting.

Analysis of delay in adjuvant chemotherapy in locally advanced rectal cancer

BACKGROUND

Adjuvant chemotherapy (AC) after neoadjuvant chemoradiation and surgical resection has been the standard of care for locally advanced rectal cancer. However, there are no evidence-based guidelines regarding the optimal timing of AC for rectal cancer. The objective of this study was to evaluate the effect of AC timing on overall survival for rectal cancer.

METHODS

The National Cancer Database (NCDB) from 2004 to 2016 was queried for primary clinical stage II or III rectal cancer patients who had undergone neoadjuvant chemoradiation followed by surgery and AC. Patients were grouped based on AC initiation: early ≤ 4 weeks, intermediate 4-8 weeks, and delayed ≥ 8 weeks. The primary outcome was overall survival.

RESULTS

We identified 8722 patients, of which 905 (10.4%) received early AC, 4621 (53.0%) intermediate AC, and 3196 (36.6%) delayed AC. Pathological lymph-node metastasis (ypN +) was positive in 73% of early AC, 74% intermediate AC, and 63% delayed AC (p < 0.05). The 5-year survival probability was 71.1% (95% CI 68-74%) for early AC, 73.2% (95% CI 72-75%) intermediate AC, and 65.8% (95% CI 64-68%) delayed AC (p < 0.001). Using Cox proportional hazard modeling, patients undergoing delayed AC had an associated decreased survival compared to patients receiving early AC (HR 1.18; 95% CI 1.028-1.353, p = 0.018) or intermediate AC (HR 1.28; 95% CI 1.179-1.395, p < 0.01).

CONCLUSIONS

Delay in AC administration may be associated with decreased 5-year survival. Compared to early or intermediate AC, patients in the delayed AC group were observed to have increased risk of death, despite having lower proportions with ypN + disease. Patients with higher socioeconomic and education status were more likely to receive early chemotherapy.

Strategies to Optimize Treatment for Locally Advanced Rectal Cancer

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

Adjuvant chemotherapy and survival outcomes in rectal cancer patients with good response (ypT0-2N0) after neoadjuvant chemoradiotherapy and surgery: A retrospective nationwide analysis

Background

For rectal cancer, it remains unclear how to incorporate tumor response to neoadjuvant chemoradiotherapy (nCRT) when deciding whether to give adjuvant chemotherapy. In this study, we aim to determinate the survival benefit of adjuvant chemotherapy for rectal cancer patients with good response (ypT0-2N0) after nCRT and surgery.

Methods

The study cohort included 720 rectal cancer patients who had good response (ypT0-2N0) after nCRT and surgery, who did or did not receive adjuvant chemotherapy between January 2007 and December 2017, from the Taiwan Cancer Registry and National Health Insurance Research database. The Kaplan-Meier method, log-rank tests, and Cox regression analysis were performed to investigate the effect of adjuvant chemotherapy on 5-year overall survival (OS) and disease-free survival (DFS).

Results

Of 720 patients, 368 (51.1%) received adjuvant chemotherapy and 352 (48.9%) did not. Patients who received adjuvant chemotherapy were more likely to be female, younger (≤ 65), with advanced clinical T (3-4)/N (1-2) classification and ypT2 classification. No significant difference in 5-year OS (p=0.681) or DFS (p=0.942) were observed by receipt of adjuvant chemotherapy or not. Multivariable analysis revealed adjuvant chemotherapy was not associated with better OS (adjusted hazard ratio [aHR], 1.03; 95% Confidence Interval [CI], 0.88-1.21) or DFS (aHR, 1.05; 95% CI, 0.89-1.24). Stratified analysis for OS and DFS found no significant protective effect in the use of adjuvant chemotherapy, even for those with advanced clinical T or N classification.

Conclusion

Adjuvant chemotherapy may be omitted in rectal cancer patients with good response (ypT0-2N0) after nCRT and surgery.

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

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