Impact of interval between neoadjuvant chemoradiotherapy and TME for locally advanced rectal cancer on pathologic response and oncologic outcome

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.

Textbook Neoadjuvant Outcome-Novel Composite Measure of Oncological Outcomes among Gastric Cancer Patients Undergoing Multimodal Treatment

The incidence of gastric cancer (GC) is expected to increase to 1.77 million cases by 2040. To improve treatment outcomes, GC patients are increasingly treated with neoadjuvant chemotherapy (NAC) prior to curative-intent resection. Although NAC enhances locoregional control and comprehensive patient care, survival rates remain poor, and further investigations should establish outcomes assessment of current clinical pathways. Individually assessed parameters have served as benchmarks for treatment quality in the past decades. The Outcome4Medicine Consensus Conference underscores the inadequacy of isolated metrics, leading to increased recognition and adoption of composite measures. One of the most simple and comprehensive is the "All or None" method, which refers to an approach where a specific set of criteria must be fulfilled for an individual to achieve the overall measure. This narrative review aims to present the rationale for the implementation of a novel composite measure, Textbook Neoadjuvant Outcome (TNO). TNO integrates five objective and well-established components: Treatment Toxicity, Laboratory Tests, Imaging, Time to Surgery, and Nutrition. It represents a desired, multidisciplinary care and hospitalization of GC patients undergoing NAC to identify the treatment- and patient-related data required to establish high-quality oncological care further. A key strength of this narrative review is the clinical feasibility and research background supporting the implementation of the first and novel composite measure representing the "ideal" and holistic care among patients with locally advanced esophago-gastric junction (EGJ) and GC in the preoperative period after NAC. Further analysis will correlate clinical outcomes with the prognostic factors evaluated within the TNO framework.

Total neoadjuvant therapy in rectal cancer: a network meta-analysis of randomized trials

PURPOSE

To assess the efficacy of total neoadjuvant therapy (TNT) for rectal carcinoma in comparison with conventional chemoradiotherapy (CRT).

METHODS

A systematic review was performed according to the PRISMA guidelines. A Bayesian network meta-analysis was done using NetMetaXL and WinBUGS. This study was registered in PROSPERO on March 3, 2022 (No. CRD-42022307867).

RESULTS

Outcomes of 2,719 patients from 10 randomized trials between 2010 and 2022 were selected. Of these 1,191 (44%) had conventional long-course CRT (50-54 Gy) and capecitabine, 506 (18%) had induction chemotherapy followed by CRT (50-54 Gy) and capecitabine (iTNT), 230 (9%) had long-course CRT (50-54 Gy) followed by consolidation chemotherapy (cTNT), and 792 (29%) undergone modified short-course radiotherapy (25 Gy) with subsequent chemotherapy (mTNT). Total pathologic complete response (pCR) was 20% in the iTNT group, 21% in the mTNT group, 22% in the cTNT group, and 12% in the CRT group. Statistically significant difference in pCR rates was detected when comparing iTNT with CRT (odds ratio [OR], 1.76; 95% credible interval [CrI], 1.06-2.8), mTNT with CRT (OR, 1.90; 95% CrI, 1.25-2.74), and cTNT with CRT groups (OR, 2.54; 95% CrI, 1.26-5.08). No differences were found in R0 resection rates. No significant difference was found in long-term outcomes.

CONCLUSION

The early administration of systemic chemotherapy in the TNT regimen has improved short-term outcomes, though long-term results are underreported. Randomized trials with survival as the endpoint are necessary to evaluate the possible advantages of TNT modes.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSION

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

Total neoadjuvant treatment to increase the clinical complete response rate for distal locally advanced rectal cancer (TESS): A study protocol of a prospective, open-label, multicenter, single-arm, phase 2 trial

BACKGROUND

Standard treatment of locally advanced rectal cancer (LARC) was neoadjuvant chemoradiotherapy (CRT), followed by total mesorectal excision (TME). Total neoadjuvant treatment (TNT), a new concept, attempts to deliver both systemic chemotherapy and neoadjuvant CRT prior to surgery. Patients treated with neoadjuvant chemotherapy were more likely to show higher tumor regression. The objective of this trial was to increase complete clinical rate (cCR) for LARC patients by optimizing tumor response, using TNT regimen as compared to conventional chemoradiotherapy. TESS, a prospective, open-label, multicenter, single-arm, phase 2 study, is underway.

METHODS

Main inclusion criteria include cT3-4aNany or cT1-4aN+ rectal adenocarcinoma aged 18-70y; Eastern Cooperative Oncology Group (ECOG) performance 0-1; location ≤5 cm from anal verge. Ninety-eight patients will receive 2 cycles of neoadjuvant chemotherapy Capeox (capecitabine + oxaliplatin) before, during, and after radiotherapy 50Gy/25 fractions, before TME (or other treatment decisions, such as Watch and Wait strategy) and adjuvant chemotherapy capecitabine 2 cycles. Primary endpoint is the cCR rate. Secondary endpoints include ratio of sphincter preservation strategy; pathological complete response rate and tumor regression grade distribution; local recurrence or metastasis; disease-free survival; locoregional recurrence-free survival; acute toxicity; surgical complications; long-term anal function; late toxicity; adverse effect, ECOG standard score, and quality of life. Adverse events are graded per Common Terminology Criteria for Adverse Events V5.0. Acute toxicity will be monitored during antitumor treatment, and late toxicity will be monitored for 3 years from the end of the first course of antitumor treatment.

DISCUSSION

The TESS trial aims to explore a new TNT strategy, which is expected to increase the rate of cCR and sphincter preservation rate. This study will provide new options and evidence for a new sandwich TNT strategy in patients with distal LARC.

Time to surgery does not affect oncologic outcomes in locally advanced gastric cancer after neoadjuvant chemotherapy: a meta-analysis

Aim: The authors conducted a meta-analysis to determine the association between time-to-surgery (TTS) after neoadjuvant chemotherapy and patient outcomes in locally advanced gastric cancer. Methods: Electronic databases were searched to identify potential studies, in which the authors compared patient outcomes between those with TTS within 4 (and 6) weeks of completion of neoadjuvant chemotherapy and those after 4 (and 6) weeks. Results: Six studies, including 1238 patients, were eligible for inclusion. Pooled data showed no significant differences in rates of pathological complete response, major pathological response, ypN0, complications, R0 resection and operative time between groups of longer TTS and shorter TTS. Conclusion: There was no statistically advantageous impact of prolonged TTS on pathological and surgical outcomes. Large, population-based studies are warranted.

Early versus delayed surgery following neoadjuvant chemoradiation for esophageal cancer: a systematic review and meta-analysis

BACKGROUND

Neoadjuvant chemoradiotherapy (nCRT) followed by surgery, is the mainstay of managing locally advanced esophageal cancer. However, the optimal timing of surgery after neoadjuvant therapy is not defined clearly.

METHODS

A systematic search of PubMed, Embase and Cochrane databases was conducted. 6-8 weeks were used as a cut-off to define early and delayed surgery groups. Overall Survival (OS) was the primary outcome, whereas pathological complete resolution (pCR), R0 resection, anastomotic leak, perioperative mortality, pulmonary complications, and major complication (> Clavien-Dindo grade 2) rates were secondary outcomes. Cohort studies and national registry bases studies were analysed separately. Survival data were pooled as Hazard Ratio (HR) and the rest as Odds Ratio (OR). According to heterogeneity, fixed-effect or random-effect models were used.

RESULTS

Twelve retrospective studies, one RCT, and six registry-based studies (13,600 participants) were included. Pooled analysis of cohort studies showed no difference in OS (HR 1.03, CI 0.91-1.16), pCR (OR 0.98, CI 0.80-1.20), R0 resection (OR 0.90, CI 0.55-I.45), mortality (OR 1.03, CI 0.59-1.77), pulmonary complications (OR 1.26, CI 0.97-1.64) or major complication rates (OR 1.29, CI 0.96-1.73). Delayed surgery led to increased leak (OR 1.48, CI 1.11-1.97). Analysis of registry studies showed that the delayed group had a better pCR rate (OR 1.12, CI 1.01-1.24), with no improvement in survival (HR 1.01, CI 0.92-1.10). Delayed surgery was associated with increased mortality (OR 1.35, CI 1.07-1.69) and major complication rate (OR 1.55, CI 1.20-2.01). Available RCT reported surgical outcomes only.

CONCLUSION

National registry-based studies' analysis shows that delay in surgery is riskier and leads to higher mortality and major complication rates. Further, well-designed RCTs are required.

Effect of interval between neoadjuvant chemoradiotherapy and surgery on disease recurrence and survival in rectal cancer: long-term results of a randomized clinical trial

BACKGROUND

The optimal timing of surgery following chemoradiotherapy (CRT) is controversial. This trial aimed to assess disease recurrence and survival rates between patients with locally advanced rectal adenocarcinoma (LARC) who underwent total mesorectal excision (TME) after a waiting interval of 8 weeks or less (classic interval; CI) versus more than 8 weeks (long interval; LI) following preoperative CRT.

METHODS

This was a phase III, single-centre, randomized clinical trial. Patients with LARC situated within 12 cm of the anal verge (T3-T4 or N+ disease) were randomized to undergo TME within or after 8 weeks after CRT.

RESULTS

Between January 2006 and January 2017, 350 patients were randomized, 175 to each group. As of February 2022, the median follow-up time was 80 (6-174) months. Among the 322 included patients (CI, 159; LI, 163) the cumulative incidence of locoregional recurrence at 5 years was 10.1 per cent in the CI group and 6.9 per cent in the LI group (P = 0.143). The cumulative incidence of distant metastasis at 5 years was 30.8 per cent in the CI group and 18.6 per cent in the LI group (sub-HR = 1.78; 95 per cent c.i. 1.14 to 2.78, P = 0.010). The disease-free survival (DFS) in each group was 59.7 and 69.9 per cent respectively (P = 0.157), and overall survival (OS) rates at 5 years were 73.6 versus 77.9 per cent (P = 0.476).

CONCLUSION

Incidence of distant metastasis decreased with an interval between CRT and surgery exceeding 8 weeks, but this did not impact on DFS or OS.

REGISTRATION NUMBER

NCT03287843 (http://www.clinicaltrials.gov).

Total Neoadjuvant Therapy for Rectal Cancer in the CAO/ARO/AIO-12 Randomized Phase 2 Trial: Early Surrogate Endpoints Revisited

Background: Early efficacy outcome measures in rectal cancer after total neoadjuvant treatment are increasingly investigated. We examined the prognostic role of pathological complete response (pCR), tumor regression grading (TRG) and neoadjuvant rectal (NAR) score for disease-free survival (DFS) in patients with rectal carcinoma treated within the CAO/ARO/AIO-12 randomized phase 2 trial. Methods: Distribution of pCR, TRG and NAR score was analyzed using the Pearson’s chi-squared test. Univariable analyses were performed using the log-rank test, stratified by treatment arm. Discrimination ability of non-pCR for DFS was assessed by analyzing the ROC curve as a function of time. Results: Of the 311 patients enrolled, 306 patients were evaluable (Arm A:156, Arm B:150). After a median follow-up of 43 months, the 3-year DFS was 73% in both groups (HR, 0.95, 95% CI, 0.63–1.45, p = 0.82). pCR tended to be higher in Arm B (17% vs. 25%, p = 0.086). In both treatment arms, pCR, TRG and NAR were significant prognostic factors for DFS, whereas survival in subgroups defined by pCR, TRG or NAR did not significantly differ between the treatment arms. The discrimination ability of non-pCR for DFS remained constant over time (C-Index 0.58) but was slightly better in Arm B (0.61 vs. 0.56). Conclusion: Although pCR, TRG and NAR were strong prognostic factors for DFS in the CAO/ARO/AIO-12 trial, their value in selecting one TNT approach over another could not be confirmed. Hence, the conclusion of a long-term survival benefit of one treatment arm based on early surrogate endpoints should be stated with caution.

Impact of the Interval between Neoadjuvant Chemotherapy and Gastrectomy on Pathological Response and Survival Outcomes for Patients with Locally Advanced Gastric Cancer: A Meta-analysis

Background

It is still unknown what is the appropriate time between neoadjuvant chemotherapy (NACT) and gastrectomy in cases of gastric cancer. To comprehend the relationship more clearly between waiting time after NACT before having a gastrectomy and survival results, a meta-analysis was done.

Methods

Retrospective and prospective research from the PubMed, Embase, and Cochrane Library databases were thoroughly reviewed. Research examining the impact of delays of 4, 4-6, and above 6 weeks between the conclusion of NACT and surgery in patients with locally advanced gastric cancer qualified as eligible studies. The pathologic complete response (pCR) rate served as the main outcome indicator. Additional outcome metrics were overall survival (OS) and survival free of illness.

Results

The meta-analysis showed that patients with locally advanced gastric cancer with a waiting time for surgery of above 4 weeks compared to those with a waiting time for surgery of below 4 weeks saw a significantly higher pCR rate (pCR) [odds ratio (OR): 1.67; 95% confidence interval (CI): 1.07-2.60; p = 0.02]. The meta-analysis found no appreciable OS differences [hazard ratio (HR): 0.93; 95% CI: 0.76-1.13; p = 0.44).

Conclusions

Time to surgery (TTS) had no effect on the survival results, according to our data. Only in the group where delaying surgery by more than 4 weeks after the end of NACT improved pathological response, but had no effect on survival.

How to cite this article

Naveed S, Banday SZ, Qari H, et al. Impact of the Interval between Neoadjuvant Chemotherapy and Gastrectomy on Pathological Response and Survival Outcomes for Patients with Locally Advanced Gastric Cancer: A Meta-analysis. Euroasian J Hepato-Gastroenterol 2022;12(2):81-91.

Clinical prediction model of pathological response following neoadjuvant chemoradiotherapy for rectal cancer

Patients with pathologic complete response (pCR) achievement can consider local excision or "watch and wait" strategy instead of a radical surgery. This study analyzed the predictive factors of pCR in rectal cancer patients who underwent radical operation after neoadjuvant chemoradiotherapy (nCRT). This study also analyzed the recurrence patterns in patients who achieved pCR and the oncologic outcomes and prognostic factors by ypStage. Between 2000 and 2013, 1,089 consecutive rectal cancer patients who underwent radical resection after nCRT were analyzed. These patients were classified into two groups according to pCR. The clinicopathologic and oncologic outcomes were analyzed and compared between the two groups. Multivariate analysis was conducted on factors related to pCR. The proportion of patients achieving pCR was 18.2% (n = 198). The pCR group demonstrated earlier clinical T and N stages, smaller tumor size, better differentiation, and a lower percentage of circumferential resection margin (CRM) involvement than did the non-pCR group. The prognostic factors associated with poorer disease-free survival were high preoperative carcinoembryonic antigen levels, non-pCR, poor histology, lymphatic/perineural invasion, and involvement of CRM. Multivariate analysis revealed that clinical node negativity, tumor size < 4 cm, and well differentiation were significant independent clinical predictors for achieving pCR. Patients with pCR displayed better long-term outcomes than those with non-pCR. The pCR-prediction model, based on predictive factors, is potentially useful for prognosis and for prescribing a treatment strategy in patients with advanced rectal cancer who need nCRT.

Mismatch repair system deficiency is associated with chemoradiotherapy resistance in locally advanced rectal adenocarcinoma patients

BACKGROUND AND OBJECTIVES

Previous studies have concluded that colorectal cancer patients with deficient mismatch repair (dMMR) usually have a good prognosis. However, some studies have suggested that the prognosis of rectal cancer patients with dMMR appears to be worse. Our aim was to investigate chemoradiotherapy resistance in dMMR rectal tumors.

METHODS

A retrospective study of 217 patients with locally advanced rectal adenocarcinoma treated with chemoradiotherapy and total mesorectal excision surgery was conducted using immunohistochemistry to determine MMR status and propensity score matching models to reduce potential confounders. Kaplan-Meier analysis, log-rank test, and Cox regression models were used to assess overall survival (OS) and disease-free survival (DFS) in patient subgroups.

RESULTS

The 3-year DFS rates were 77.1% and 56.7% in the pMMR and dMMR groups, respectively. The pMMR group had significantly better DFS than the dMMR group (hazard ratio [HR], 2.07; 95% confidence interval [CI], 1.10-3.91; p = 0.019). However, there was no significant difference in OS between the two groups (45.7 [interquartile range, IQR], 39.3-72.1] vs. 47.5 [IQR, 29.5-72.1]) (HR, 1.39; 95% CI, 0.70-2.77; p = 0.35). Neither OS nor DFS was significantly different between the neoadjuvant chemoradiotherapy and postoperative chemoradiotherapy groups.

CONCLUSION

Locally advanced dMMR rectal adenocarcinoma exhibits greater chemoradiotherapy resistance than pMMR.

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

Simple Summary

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

Abstract

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

Association of Delayed Surgery With Oncologic Long-term Outcomes in Patients With Locally Advanced Rectal Cancer Not Responding to Preoperative Chemoradiation

Importance

Extending the interval between the end of neoadjuvant chemoradiotherapy (CRT) and surgery may enhance tumor response in patients with locally advanced rectal cancer. However, data on the association of delaying surgery with long-term outcome in patients who had a minor or poor response are lacking.

Objective

To assess a large series of patients who had minor or no tumor response to CRT and the association of shorter or longer waiting times between CRT and surgery with short- and long-term outcomes.

Design, Setting, and Participants

This is a multicenter retrospective cohort study. Data from 1701 consecutive patients with rectal cancer treated in 12 Italian referral centers were analyzed for colorectal surgery between January 2000 and December 2014. Patients with a minor or null tumor response (ypT stage of 2 to 3 or ypN positive) stage greater than 0 to neoadjuvant CRT were selected for the study. The data were analyzed between March and July 2020.

Exposures

Patients who had a minor or null tumor response were divided into 2 groups according to the wait time between neoadjuvant therapy end and surgery. Differences in surgical and oncological outcomes between these 2 groups were explored.

Main Outcomes and Measures

The primary outcomes were overall and disease-free survival between the 2 groups.

Results

Of a total of 1064 patients, 654 (61.5%) were male, and the median (IQR) age was 64 (55-71) years. A total of 579 patients (54.4%) had a shorter wait time (8 weeks or less) 485 patients (45.6%) had a longer wait time (greater than 8 weeks). A longer waiting time before surgery was associated with worse 5- and 10-year overall survival rates (67.6% [95% CI, 63.1%-71.7%] vs 80.3% [95% CI, 76.5%-83.6%] at 5 years; 40.1% [95% CI, 33.5%-46.5%] vs 57.8% [95% CI, 52.1%-63.0%] at 10 years; P < .001). Also, delayed surgery was associated with worse 5- and 10-year disease-free survival (59.6% [95% CI, 54.9%-63.9%] vs 72.0% [95% CI, 67.9%-75.7%] at 5 years; 36.2% [95% CI, 29.9%-42.4%] vs 53.9% [95% CI, 48.5%-59.1%] at 10 years; P < .001). At multivariate analysis, a longer waiting time was associated with an augmented risk of death (hazard ratio, 1.84; 95% CI, 1.50-2.26; P < .001) and death/recurrence (hazard ratio, 1.69; 95% CI, 1.39-2.04; P < .001).

Conclusions and Relevance

In this cohort study, a longer interval before surgery after completing neoadjuvant CRT was associated with worse overall and disease-free survival in tumors with a poor pathological response to preoperative CRT. Based on these findings, patients who do not respond well to CRT should be identified early after the end of CRT and undergo surgery without delay.

The efficacy and safety of different radiotherapy doses in neoadjuvant chemoradiotherapy for locally advanced rectal cancer

Background

This study aimed to evaluate efficacy and adverse effects of different radiotherapy (RT) doses in neoadjuvant chemoradiotherapy for locally advanced rectal cancer.

Methods

Fifty-nine patients with locally advanced rectal cancer who underwent neoadjuvant chemoradiotherapy in hospital between January 2015 and May 2017 were enrolled in retrospective analysis. The patients were divided into the 56-Gy group and the 50-Gy group. The concurrent chemotherapy regimen was based on capecitabine. All patients received one cycle of oxaliplatin combined with capecitabine induction chemotherapy. All patients completed neoadjuvant chemoradiotherapy and received radical surgery.

Results

Of the patients in this study, 29 patients and 30 patients received a radiation dose of 56- and 50-Gy, respectively. All clinical characteristics were matched between the two groups. All patients received surgery 6 to 8 weeks after completing RT. The therapeutical effective rate in the 56-Gy group was 93.10% (27/29), compared with 66.67% in the 50-Gy group (20/30); the difference between the two groups was statistically significant (χ²=6.36, P=0.01). The pathological complete remission (pCR) rate in the 56-Gy group (37.93%, 11/29) was statistically significantly higher than that in the 50-Gy group (13.33%, 4/30) (χ²=4.71, P=0.030). The anal preservation rate in the 56-Gy group (65.5%, 19/29) was statistically significantly higher than that in the 50-Gy group (33.33%, 10/30) (χ²=6.11, P=0.01). The 56-Gy group had a local recurrence rate of 0% (0/29) and a distant metastasis rate of 10.34% (3/29), while the 50-Gy group had a local recurrence rate of 6.67% (2/30) and a distant metastasis rate of 16.67% (5/30); no significant difference existed between the two groups (χ²=2.00, 0.50, P=0.16, 0.48). The incidence of adverse reactions (gastrointestinal reactions, bone marrow suppression, and perianal skin reactions) in the 56-Gy group was not significantly different from that in the 50-Gy group (P>0.05).

Conclusions

Increasing the radiation dose can significantly improve the anal preservation and pCR rates of patients with locally advanced rectal cancer, thus improving their life quality. Moreover, it does not increase the rates of recurrence or adverse reactions. Our findings have certain clinical significance, but further prospective study is needed.

Total Neoadjuvant Therapy (TNT) versus Standard Neoadjuvant Chemoradiotherapy for Locally Advanced Rectal Cancer: A Systematic Review and Meta-Analysis

BACKGROUND

Total neoadjuvant therapy (TNT) is a novel approach for locally advanced rectal cancer (LARC), which attempts to deliver both systemic chemotherapy and neoadjuvant chemoradiotherapy prior to surgery. However, its efficacy and safety remain controversial in randomized controlled trials (RCTs). We conducted this meta-analysis to assess such concerns.

MATERIALS AND METHODS

Head-to-head phase II/III RCTs were searched in Embase, PubMed, Web of Science, and the Cochrane Library, as well as other sources. The primary endpoint was pathologic complete response (pCR). Secondary endpoints were disease-free survival (DFS), overall survival (OS), local recurrence-free survival, distant metastasis-free survival, and the R0 resection rate.

RESULTS

Eight phase II/III RCTs involving 2,196 patients with LARC were assessed. The primary analysis demonstrated a statistically significant improvement in the pCR rate for TNT treatment (odds ratio, 1.77; 95% confidence interval [CI], 1.28-2.45; p = .0005). TNT treatment also showed improvements in DFS and OS outcomes compared with standard chemoradiotherapy (hazard ratio [HR], 0.83; 95% CI, 0.72-0.96; p = .03 and HR, 0.88; 95% CI, 0.74-1.05; p = .15). In addition, TNT treatment showed significant efficacy in reducing the risk of distant metastasis (HR, 0.81; 95% CI, 0.68-0.95; p = .012).

CONCLUSION

The overall pCR rate may be improved with TNT compared with standard treatment. The TNT strategy may also improve DFS and OS and reduce the risk of distant metastasis.

IMPLICATIONS FOR PRACTICE

Locally advanced rectal cancer (LARC) is a relatively common disease, with a poor prognosis because of its high metastatic potential. The role of total neoadjuvant therapy (TNT) has always been controversial. This meta-analysis found that TNT in LARC is associated with a significant improvement in overall pathologic complete response rate, disease-free survival, overall survival, and distant metastasis-free survival compared with standard treatment. TNT is a promising strategy for LARC, especially for patients who have little desire for surgery.

Improvement in the Assessment of Response to Preoperative Chemoradiotherapy for Rectal Cancer Using Magnetic Resonance Imaging and a Multigene Biomarker

The response to preoperative chemoradiotherapy (PCRT) is correlated with oncologic outcomes in patients with locally advanced rectal cancer. Accurate prediction of PCRT response before surgery can provide crucial information to aid clinicians in further treatment planning. This study aimed to develop an evaluation tool incorporating a genetic biomarker and magnetic resonance imaging (MRI) to improve the assessment of response in post-CRT patients with locally advanced rectal cancer. A total of 198 patients who underwent PCRT followed by surgical resection for locally advanced rectal cancer between 2010 and 2016 were included in this study. Each patient's response prediction index (RPI) score, a multigene biomarker developed in our previous study, and magnetic resonance tumor regression grade (mrTRG) score were added to create a new predictive value for pathologic response after PCRT, called the combined radiation prediction value (cRPV). Based on the new value, 121 and 77 patients were predicted to be good and poor responders, respectively, showing significantly different cRPV values (p = 0.001). With an overall predictive accuracy of 84.8%, cRPV was superior to mrTRG and RPI for the prediction of pathologic chemoradiotherapy response (mrTRG, 69.2%; RPI, 77.3%). In multivariate analysis, cRPV was found to be the sole predictor of tumor response (odds ratio, 32.211; 95% confidence interval, 14.408-72.011; p = 0.001). With its good predictive value for final pathologic regression, cRPV may be a valuable tool for assessing the response to PCRT before surgery.

Temporal determinants of tumour response to neoadjuvant rectal radiotherapy

Introduction

In locally advanced rectal cancer, longer delay to surgery after neoadjuvant radiotherapy increases the likelihood of histopathological tumour response. Chronomodulated radiotherapy in rectal cancer has recently been reported as a factor increasing tumour response to neoadjuvant treatment in patients having earlier surgery, with patients receiving a larger proportion of afternoon treatments showing improved response. This paper aims to replicate this work by exploring the impact of these two temporal factors, independently and in combination, on histopathological tumour response in rectal cancer patients.

Methods

A retrospective review of all patients with rectal adenocarcinoma who received long course (≥24 fractions) neoadjuvant radiotherapy with or without chemotherapy at a tertiary referral centre was conducted. Delay to surgery and radiotherapy treatment time were correlated to clinicopathologic characteristics with a particular focus on tumour regression grade. A review of the literature and meta-analysis were also conducted to ascertain the impact of time to surgery from preoperative radiotherapy on tumour regression.

Results

From a cohort of 367 patients, 197 patients met the inclusion criteria. Complete pathologic response (AJCC regression grade 0) was seen in 46 (23%) patients with a further 44 patients (22%) having at most small groups of residual cells (AJCC regression grade 1). Median time to surgery was 63 days, and no statistically significant difference was seen in tumour regression between patients having early or late surgery. There was a non-significant trend towards a larger proportion of morning treatments in patients with grade 0 or 1 regression (p = 0.077). There was no difference in tumour regression when composite groups of the two temporal variables were analysed. Visualisation of data from 39 reviewed papers (describing 27379 patients) demonstrated a plateau of response to neoadjuvant radiotherapy after approximately 60 days, and a meta-analysis found improved complete pathologic response in patients having later surgery.

Conclusions

There was no observed benefit of chronomodulated radiotherapy in our cohort of rectal cancer patients. Review of the literature and meta-analysis confirms the benefit of delayed surgery, with a plateau in complete response rates at approximately 60-days between completion of radiotherapy and surgery. In our cohort, time to surgery for the majority of our patients lay along this plateau and this may be a more dominant factor in determining response to neoadjuvant therapy, obscuring any effects of chronomodulation on tumour response. We would recommend surgery be performed between 8 and 11 weeks after completion of neoadjuvant radiotherapy in patients with locally advanced rectal cancer.

Improved response rate in patients with prognostically poor locally advanced rectal cancer after treatment with induction chemotherapy and chemoradiotherapy when compared with chemoradiotherapy alone: A matched case-control study

INTRODUCTION

The addition of induction chemotherapy (ICT) to neoadjuvant chemoradiotherapy (CRT) has the potential to improve outcomes in patients with locally advanced rectal cancer (LARC). However, patient selection is essential to prevent overtreatment. This study compared the complete response (CR) rate after treatment with and without ICT of LARC patients with prognostically poor characteristics.

METHODS

All LARC patients who were treated with neoadjuvant CRT, whether or not preceded by ICT, and who underwent surgery or were considered for a wait-and-see strategy between January 2016 and March 2020 in the Catharina Hospital Eindhoven, were retrospectively selected. LARC was defined as any T4 tumour, or a T2/T3 tumour with extramural venous invasion and/or tumour deposits and/or N2 lymph node status, and/or mesorectal fascia involvement (T3 tumours only). Case-control matching was performed based on the aforementioned characteristics.

RESULTS

Of 242 patients, 178 (74%) received CRT (CRT-group) and 64 patients (26%) received ICT followed by CRT (ICT-group). In the ICT-group, 3 patients (5%) did not receive the minimum of three cycles. In addition, in this selected cohort, compliance with radiotherapy was 100% in the ICT-group and 97% in the CRT-group. The CR rate was 30% in the ICT-group and 15% in the CRT-group (p = 0.011). After case-control matching, the CR rate was 28% and 9%, respectively (p = 0.013).

CONCLUSION

Treatment including ICT seemed well tolerated and resulted in a high CR rate. Hence, this treatment strategy may facilitate organ preservation and improve survival in LARC patients with prognostically poor characteristics.

Predictive Factors for Pathologic Complete Response Following Neoadjuvant Chemoradiotherapy for Rectal Cancer

Background:

An accurate assessment of potential pathologic complete response(pCR) following neoadjuvant chemoradiotherapy(NCRT) is important for the appropriate treatment of rectal cancer. However, the factors that predict the response to neoadjuvant chemoradiotherapy have not been well defined. Therefore, this study analyzed the predictive factors on the development of pCR after neoadjuvant chemoradiation for rectal cancer.

Methods:

From January 2008 to January 2018, a total of 432 consecutive patients from a single institution patients who underwent a long-course neoadjuvant chemoradiotherapy were reviewed in this study. The clinicopathological features were analyzed to identify predictive factors for pathologic complete response in rectal cancer after neoadjuvant chemoradiation.

Results:

The rate of pathologic complete response in rectal cancer after neoadjuvant chemoradiation was 20.8%, patients were divided into the pCR and non-pCR groups. The two groups were well balanced in terms of age, gender, body mass index, ASA score, tumor stage, tumor differentiation, tumor location, surgical procedure, chemotherapy regimen and radiation dose. The multivariate analysis revealed that a pretreatment carcinoembryonic antigen (CEA) level of ≤5 ng/mL and an interval of ≥8 weeks between the completion of chemoradiation and surgical resection were independent risk factors of an increased rate of pCR.

Conclusions:

Pretreatment carcinoembryonic antigen (CEA) level of ≤5 ng/mL and an interval of ≥8 weeks between the completion of chemoradiation and surgical resection are predictive factors for pathologic complete response in rectal cancer after neoadjuvant chemoradiation. Using these predictive factors, we can predict the prognosis of patients and develop adaptive treatment strategies. A wait-and-see policy might be possible in highly selective cases.

Impact of the Interval Between Neoadjuvant Chemotherapy and Gastrectomy on Short- and Long-Term Outcomes for Patients with Advanced Gastric Cancer

BACKGROUND

The optimal time between neoadjuvant chemotherapy (NAC) and gastrectomy for gastric cancer (GC) remains unknown. This study aimed to investigate the association between the time-to-surgery (TTS) interval and the major pathologic response (mPR).

METHODS

In this study, 280 consecutive GC patients who underwent NAC followed by gastrectomy between 2014 and 2018 were retrospectively analyzed by the use of prospectively collected databases from three major GC treatment centers in Lithuania and Estonia. Based on TTS, they were grouped into three interval categories: the early-surgery group (ESG: ≤ 30 days; n = 70), the standard-surgery group (SSG: 31-43 days; n = 138), and the delayed-surgery group (DSG: ≥ 44 days, n = 72). The primary outcome of the study was the mPR rate. The secondary end points were postoperative morbidity, mortality, oncologic safety (measured as the number of resected lymph nodes and radicality), and long-term outcomes.

RESULTS

The mPR rate for the ESG group (32.9%) was significantly higher than for the SSG group (20.3%) or the DSG group (16.7%) (p = 0.047). Furthermore, after adjustment for patient, tumor, and treatment characteristics, the odds for achievement of mPR were twofold higher for the patients undergoing early surgery (odds ratio [OR] 2.09; 95% conflidence interval [CI] 1.01-4.34; p = 0.047). Overall morbidity, severe complications, 30-day mortality, R0 resection, and retrieval of at least 15 lymph nodes rates were similar across the study groups. In addition, the long-term outcomes did not differ between the study groups.

CONCLUSIONS

This study suggests that an interval of more than 30 days between the end of NAC and gastrectomy is associated with a higher mPR rate, the same oncologic safety of surgery, and similar morbidity and mortality.

The Predictive Value of Pre-/Postneoadjuvant Chemoradiotherapy MRI Characteristics for Patient Outcomes in Locally Advanced Rectal Cancer

RATIONALE AND OBJECTIVES

This study aimed to investigate the predictive value of pre-/postneoadjuvant chemoradiotherapy (nCRT) magnetic resonance imaging (MRI) characteristics for the long-term survival outcomes in patients with locally advanced rectal cancer (LARC).

MATERIALS AND METHODS

We retrospectively evaluated pre- and post-nCRT MRI and clinicopathologic characteristics of LARC patients. The 3-year disease-free survival (DFS) was estimated using the Kaplan-Meier product-limit method. Associations between MRI variabilities and survival outcomes were assessed using Cox proportional hazards model.

RESULTS

In total, 171 LARC patients (112 men and 59 women) with a median age of 55 years (range, 27-82 years) treated with nCRT were evaluated. The median follow-up was 47.6 months, and the 3-, 4-, and 5-year DFS in the overall cohort was 76.6%, 74.5%, and 73.7%, respectively. MRI assessment of extramural venous invasion (mrEMVI) positivity was a significant independent adverse factor of long-term survival (hazard ratio [HR] = 2.589, 95% confidence interval [CI] = 1.398-4.794, p = 0.002) on multivariate analysis. Patients with positive mrEMVI had significantly lower 3-year DFS than those with negative mrEMVI (52.6 months vs 65.1 months; p = 0.003). Moreover, the tumor regression grade on MRI (mrTRG) also significantly correlated with survival outcomes in patients with LARC. Patients with partial response on post-nCRT MRI (mrPR) showed short DFS than those with complete response (mrCR; HR = 4.914, 95% CI = 1.176-20.533, p = 0.029). The 3-year DFS of mrCR and mrPR patients were 74.3 months and 58.9 months, respectively (p = 0.011).

CONCLUSION

The pre-/post-nCRT MRI characteristics may be used to long-term survival stratification in LARC patients. mrEMVI positivity was an independent adverse prognostic indicator for 3-year DFS. Further, mrTRG may also be a predictive factor for the prognosis of LARC patients. The pre-/post-nCRT MR imaging may offer more information for providing individualized treatment.

Watch and wait approach in rectal cancer: Current controversies and future directions

According to the main international clinical guidelines, the recommended treatment for locally-advanced rectal cancer is neoadjuvant chemoradiotherapy followed by surgery. However, doubts have been raised about the appropriate definition of clinical complete response (cCR) after neoadjuvant therapy and the role of surgery in patients who achieve a cCR. Surgical resection is associated with significant morbidity and decreased quality of life (QoL), which is especially relevant given the favourable prognosis in this patient subset. Accordingly, there has been a growing interest in alternative approaches with less morbidity, including the organ-preserving watch and wait strategy, in which surgery is omitted in patients who have achieved a cCR. These patients are managed with a specific follow-up protocol to ensure adequate cancer control, including the early identification of recurrent disease. However, there are several open questions about this strategy, including patient selection, the clinical and radiological criteria to accurately determine cCR, the duration of neoadjuvant treatment, the role of dose intensification (chemotherapy and/or radiotherapy), optimal follow-up protocols, and the future perspectives of this approach. In the present review, we summarize the available evidence on the watch and wait strategy in this clinical scenario, including ongoing clinical trials, QoL in these patients, and the controversies surrounding this treatment approach.

Consolidation chemotherapy may improve pathological complete response for locally advanced rectal cancer after neoadjuvant chemoradiotherapy: a retrospective study

BACKGROUND

Patients with locally advanced rectal cancer (LARC) have an improved prognosis if achieved a pathological complete response (pCR) on account of neoadjuvant chemoradiation therapy (nCRT). However, the proportion of patients achieving pCR is only 8-24%. The purpose of this study was to explore whether the addition of consolidation chemotherapy to nCRT could improve pCR rate in patients with LARC.

MATERIALS AND METHODS

The subjects were 144 individuals with clinical stage II (T3-4, N0) or III (any T, N1-2) LARC who had received neoadjuvant CRT followed by total mesorectal excision (TME). Eighty-three patients in the consolidation chemotherapy group received two cycles XELOX between CRT and TME, while 61 patients in the standard treatment group without consolidation chemotherapy. The pCR (ypT0N0), tumor downstaging (ypT0-2N0) after TME and adverse events (AEs) during and post treatment were compared between the treatment groups using multivariable logistic regression analysis. To adjust the unbalanced variables for the primary endpoint, logistic regression analysis and stratified analysis were performed.

RESULTS

The consolidation chemotherapy group improved pCR rate (19.3% vs 4.9%, p = 0.01) and tumor downstaging rate (45.8% vs 24.6%, p = 0.009) compared to the standard treatment group. After adjustment for clinical tumor stage, clinical nodal stage and time interval to surgery, patients with consolidation chemotherapy were more likely to reach pCR (adjusted odds ratio 4.91, 95% CI [1.01-23.79], p = 0.048). AEs during and post treatment in the two groups were 54.1% vs 49.3% (p = 0.57), respectively. In addition, the incidence of any grade 1-2 AEs in the two groups was 93.4% vs 95.1% (p = 0.93), while the incidence of grade 3 AEs was 1.6% versus 2.4% (p = 0.74), respectively. No grade 4 AEs occurred in two groups.

CONCLUSIONS

The addition of neoadjuvant consolidation chemotherapy after CRT significantly increased the pCR rate and did not increase the AEs during and post treatment and in patients with LARC.

Delaying surgery by more than 10 weeks after long-course neoadjuvant radiotherapy in locally advanced rectal cancer patients improves pathologic complete response

BACKGROUND

We currently do not know the optimal time interval between the end of chemoradiotherapy and surgery. Longer intervals have been associated with a higher pathological response rate, worse pathological outcomes and more morbidity. The aim of this study was to evaluate the effect and safety of the current trend of increasing time interval between the end of chemoradiotherapy and surgery (< 10 weeks vs. ≥ 10 weeks) on postoperative morbidity and pathological outcomes. This study analyzed 232 consecutive patients with locally advanced rectal cancer treated with long-course neoadjuvant chemoradiotherapy from January 2012 to August 2018. 125 patients underwent surgery before 10 weeks from the end of chemoradiotherapy (Group 1) and 107 patients underwent surgery after 10 or more weeks after the end of chemoradiotherapy (Group 2). Results have shown that wait for ≥ 10 weeks did not compromise surgical safety. Pathological complete response and tumor stage was statistically significant among groups. The effect of wait for ≥ 10 weeks before surgery shown higher tumor regression than the first group (Group 1, 12.8% vs Group 2, 31.8%; p < 0.001). On multivariate analysis, wait for ≥ 10 weeks was associated with pathological compete response. Patients from the second group were four time more likely to achieve pathologic complete response than patients from the first group (OR, 4.27 95%CI 1.60-11.40; p = 0.004). Patients who undergo surgery after ≥ 10 weeks of the end of chemoradiotherapy are four time more likely to achieve complete tumor remission without compromise surgical safety or postoperative morbidity.

Short-Term Clinical and Oncological Outcome of Prolonging Operation Interval After Neoadjuvant Chemoradiotherapy for Locally Advanced Middle and Low Rectal Cancer

Purpose

The purpose of this study is to evaluate the short-term clinical and oncological outcome of prolonging operation interval to 11 weeks after the end of radiotherapy for locally advanced middle and low rectal cancer.

Methods

A total of 123 patients with stage II/III (cT3/T4 or N+) low and middle rectal cancer who had undergone operation after neoadjuvant chemoradiotherapy were selected. According to the interval time between the last radiotherapy and operation, they were assigned to a short-interval group (SG, <11 weeks, n=66) and long-interval group (LG, ≥11 weeks, n=57). The relations among interval time and short-term clinical outcome and oncological outcome were analyzed.

Results

The analysis found that basic information, clinical characteristics, and preoperative treatment between the two groups had no significant difference. There were no differences in operation time, estimated intraoperative blood loss and postoperative complications. The rate of sphincter preservation in the low and middle rectum was 66.7% in the short-interval group and 59.7% in the long-interval group (P=0.42). The incidence of anastomotic leak in the long-interval group was higher than that in the short-interval group (P=0.08). There was no significant difference in the recovery time of intestinal function and median duration of hospitalization between the two groups. The pathological complete remission rate was 17.07%. Multivariate analysis showed interval time had no influence on pathological complete remission. There was no significant difference in 3-year overall survival and 3-year disease-free survival between the two groups. The risk of recurrence and metastasis in patients with positive lymph nodes was higher than those with negative lymph nodes (P<0.05), HR=4.812 (95% CI 2.4–9.648).

Conclusion

Prolonging the interval time of operation to 11 weeks after neoadjuvant chemoradiotherapy for middle and low rectal cancer does not improve the pathologic complete remission, morbidity, and mortality. There was no significant effect on oncologic outcome after prolonging the operation interval. Therefore, it is safe to prolong the interval of operation to 11 weeks.

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

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

Pathological complete response due to a prolonged time interval between preoperative chemoradiation and surgery in locally advanced rectal cancer: analysis from the German StuDoQ|Rectalcarcinoma registry

Background

Preoperative chemoradiotherapy is the recommended standard of care for patients with local advanced rectal cancer. However, it remains unclear, whether a prolonged time interval to surgery results in an increased perioperative morbidity, reduced TME quality or better pathological response. Aim of this study was to determine the time interval for best pathological response and perioperative outcome compared to current recommended interval of 6 to 8 weeks.

Methods

This is a retrospective analysis of the German StuDoQ|Rectalcarcinoma registry. Patients were grouped for the time intervals of “less than 6 weeks”, “6 to 8 weeks”, “8 to 10 weeks” and “more than 10 weeks”. Primary endpoint was pathological response, secondary endpoint TME quality and complications according to Clavien-Dindo classification.

Results

Due to our inclusion criteria (preoperative chemoradiation, surgery in curative intention, M0), 1.809 of 9.560 patients were suitable for analysis. We observed a trend for increased rates of pathological complete response (pCR: ypT0ypN0) and pathological good response (pGR: ypT0-1ypN0) for groups with a prolonged time interval which was not significant. Ultimately, it led to a steady state of pCR (16.5%) and pGR (22.6%) in “8 to 10” and “more than 10” weeks. We were not able to observe any differences between the subgroups in perioperative morbidity, proportion of rectal extirpation (for cancer of the lower third) or difference in TME quality.

Conclusion

A prolonged time interval between neoadjuvant chemoradiation can be performed, as the rate of pCR seems to be increased without influencing perioperative morbidity.

Short-course or long-course radiation therapy as a part of a neoadjuvant regimen for stage II & III rectal adenocarcinoma?

The aim of this mini-review is to compare and contrast the pros and cons of short-course and long-course neoadjuvant chemoradiation therapy regimens for stage II & III rectal adenocarcinoma. Multiple trials have demonstrated the equal efficacy and safety of short-course and long-course radiation therapy as a part of neoadjuvant regimens. Published data also shows that total neoadjuvant therapy could be more successful than neoadjuvant chemoradiation followed by adjuvant chemotherapy. This review points out future research directions for patients with locally advanced rectal adenocarcinoma such as comparing total neoadjuvant therapy that contains a short-course of radiation therapy to the standard of care, and evaluating how the sequence of short-course radiation therapy and chemotherapy in the total neoadjuvant therapy impacts the pathological complete response (pCR) rate, local control, and survival outcomes.

Gastrointestinal Malignancies and the COVID-19 Pandemic: Evidence-Based Triage to Surgery

BACKGROUND

The COVID-19 pandemic has led to widespread cancelation of electively scheduled surgeries, including for colorectal, pancreatic, and gastric cancer. The American College of Surgeons and the Society of Surgical Oncology have released guidelines for triage of these procedures. We seek to synthesize available evidence on delayed resection and oncologic outcomes, while also providing a critical assessment of the released guidelines.

METHODS

A systematic review was conducted to identify literature between 2005 and 2020 investigating the impact of time to surgery on oncologic outcomes in colorectal, pancreatic, and gastric cancer.

RESULTS

For colorectal cancer, 1066 abstracts were screened and 43 papers were included. In primarily resected colon cancer, delay over 30 to 40 days is associated with lower survival. In rectal cancer, time to surgery over 7 to 8 weeks following neoadjuvant therapy is associated with decreased survival. Three hundred ninety-four abstracts were screened for pancreatic cancer and nine studies were included. Two studies demonstrate increased unexpected progression with delayed surgery over 30 days. Out of 633 abstracts screened for gastric cancer, six studies were included. No identified study demonstrated worse survival with increased time to surgery.

CONCLUSION

Moderate evidence suggests that delayed resection of colorectal cancer worsens survival; the impact of time to surgery on gastric and pancreatic cancer outcomes is uncertain. Early resection of gastrointestinal malignancies provides the best chance for curative therapy. During the COVID-19 pandemic, prioritization of procedures should account for available evidence on time to surgery and oncologic outcomes.

Effect of interval between preoperative radiotherapy and surgery on clinical outcome and radiation proctitis in rectal cancer from FOWARC trial

Objective

The aim of this study was to evaluate the effect of the interval between CRT and surgery on radiation proctitis, the pathologic response, and postoperative morbidity.

Methods

This was a cohort study from a phase III, randomized controlled trial (FOWARC study, NCT01211210). Data were retrieved from the leading center of the trial. Patients were divided into the short‐interval (≤7 weeks) group and the long‐interval (>7 weeks) group. The rate of radiation proctitis, pathologic complete regression (pCR) and morbidities were calculated for each group. Multivariate analysis was used to verify the impact of interval on radiation proctitis.

Results

Surgery was performed in 60 patients after an interval of ≤7 weeks and in 97 patients after an interval of >7 weeks. The two groups according to interval were comparable in terms of baseline demographic and clinicotherapeutic characteristics. Radiation proctitis was identified by imaging in 9 (15.0%) patients in short‐interval group and in 31 (32.0%) patients in long‐interval group (P = .018). Multivariate analysis confirmed the correlation between long interval and radiation proctitis (P = .018). The long interval was significantly associated with longer median operation time compared to the short interval (P = .022). The rates of pCR and postoperative complications were not different between two groups.

Conclusions

A longer interval after CRT may be associated with higher rate of radiation proctitis and longer operation time. Moreover it did not increase the rate of pCR.

Executive Summary of the American Radium Society Appropriate Use Criteria for Local Excision in Rectal Cancer

The goal of treatment for early stage rectal cancer is to optimize oncologic outcome while minimizing effect of treatment on quality of life. The standard of care treatment for most early rectal cancers is radical surgery alone. Given the morbidity associated with radical surgery, local excision for early rectal cancers has been explored as an alternative approach associated with lower rates of morbidity. The American Radium Society Appropriate Use Criteria presented in this manuscript are evidence-based guidelines for the use of local excision in early stage rectal cancer that include an extensive analysis of current medical literature from peer-reviewed journals and the application of a well-established consensus methodology (modified Delphi) used by a multidisciplinary expert panel to rate the appropriateness of imaging and treatment procedures. In those instances where evidence is lacking or not definitive, expert opinion may be used to recommend imaging or treatment. These guidelines are intended for the use of all practitioners and patients who desire information regarding the use of local excision in rectal cancer.

Neoadjuvant rectal score as individual-level surrogate for disease-free survival in rectal cancer in the CAO/ARO/AIO-04 randomized phase III trial

Background

Surrogate end points in rectal cancer after preoperative chemoradiation are lacking as their statistical validation poses major challenges, including confirmation based on large phase III trials. We examined the prognostic role and individual-level surrogacy of neoadjuvant rectal (NAR) score that incorporates weighted cT, ypT and ypN categories for disease-free survival (DFS) in 1191 patients with rectal carcinoma treated within the CAO/ARO/AIO-04 phase III trial.

Patients and methods

Cox regression models adjusted for treatment arm, resection status, and NAR score were used in multivariable analysis. The four Prentice criteria (PC1-4) were used to assess individual-level surrogacy of NAR for DFS.

Results

After a median follow-up of 50 months, the addition of oxaliplatin to fluorouracil-based chemoradiotherapy (CRT) significantly improved 3-year DFS [75.9% (95% confidence interval [CI] 72.30% to 79.50%) versus 71.3% (95% CI 67.60% to 74.90%); P = 0.034; PC 1) and resulted in a shift toward lower NAR groups (P = 0.034, PC 2) compared with fluorouracil-only CRT. The 3-year DFS was 91.7% (95% CI 88.2% to 95.2%), 81.8% (95% CI 78.4% to 85.1%), and 58.1% (95% CI 52.4% to 63.9%) for low, intermediate, and high NAR score, respectively (P < 0.001; PC 3). NAR score remained an independent prognostic factor for DFS [low versus high NAR: hazard ratio (HR) 4.670; 95% CI 3.106-7.020; P < 0.001; low versus intermediate NAR: HR 1.971; 95% CI 1.303-2.98; P = 0.001] in multivariable analysis. Notwithstanding the inherent methodological difficulty in interpretation of PC 4 to establish surrogacy, the treatment effect on DFS was captured by NAR, supporting satisfaction of individual-level PC 4.

Conclusion

Our study validates the prognostic role and individual-level surrogacy of NAR score for DFS within a large randomized phase III trial. NAR score could help oncologists to speed up response-adapted therapeutic decision, and further large phase III trial data sets should aim to confirm trial-level surrogacy.

Optimal interval to surgery after chemoradiotherapy in rectal cancer: A protocol for systematic review and network meta-analysis

BACKGROUND

Rectal cancer is the second leading cause of cancer-related death in the Western world. Preoperative neoadjuvant chemoradiotherapy (nCRT) has been widely performed in the treatment of rectal cancer patients. However, there is no consensus on the length of waiting interval between the end of preoperative nCRT and surgery. Present network meta-analysis (NMA) aims to compare the differences of effect between all available interval to surgery after nCRT in rectal cancer in improving overall survival, disease-free survival and pathologic complete response (pCR) rate, and to rate the certainty of evidence from present NMA.

METHOD

We will systematically search PubMed, EMBASE, Chinese Biomedical Literature Database, and Cochrane Central Register of Controlled Trials (CENTRAL) databases to identify studies assessing the interval to surgery after CRT in rectal cancer. We will conduct this systematic review and meta-analysis using Bayesian method and report the full-text according to Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) Extension Vision statement (PRISMA-NMA). We will assess the risk of bias of individual study using the Newcastle-Ottawa Scale and Cochrane Handbook V.5.1.0. We will also use the advance of GRADE to rate the certainty of NMA. Data will be analyzed by using R software V.3.4.1.

RESULTS

The results of this study will be published in a peer-reviewed journal.

CONCLUSION

To the best of our knowledge, this systematic review and NMA will first use both direct and indirect evidence to compare the differences of all available interval to surgery after CRT in rectal cancer. This is a protocol of systematic review and meta-analysis, so the ethical approval and patient consent are not required.

Timing of surgery following neoadjuvant chemoradiation in rectal cancer: a retrospective analysis from an academic medical center

Background

Neoadjuvant chemoradiotherapy (nCRT) has been shown to achieve decreased local recurrence (LR) with lower toxicity in rectal cancer patients, but data confirming the optimal timing of surgery following this therapy is less robust.

Methods

The University of Iowa Cancer Registry was queried to identify all patients with stages II-III rectal cancer who received nCRT and surgery from 2000 through 2012. Primary endpoints were time interval to surgery (TI), and overall survival (OS). Secondary endpoints included pathologic outcomes, perioperative morbidities and postoperative complications. Patient characteristics and treatment regimens were compared. Univariate Cox proportional hazard models were used to study the association between TI and OS. Associations of TI with secondary endpoints were tested using Chi-square tests of association.

Results

Eighty-seven patients presented with stages II-III rectal cancer. Mean TI was 9.92 weeks. There was no significant association between TI and OS when comparing <8 to ≥8 weeks (P=0.23) or when considering the interval as a continuous variable (P=0.85). Increased LOS [median 7.00 days, P=0.05, HR 1.03 (1.00-1.06)] did correlate with worse survival outcomes. Delaying surgery beyond 8 weeks was associated with increased risk for wound infection (P=0.05).

Conclusions

OS was not influenced by longer intervals between nCRT and surgery. Delaying surgery beyond 8 weeks was associated with increased risk for wound infection.

Meta-analysis of the effect of extending the interval after long-course chemoradiotherapy before surgery in locally advanced rectal cancer

BACKGROUND

The current standard of care in locally advanced rectal cancer (LARC) is neoadjuvant long-course chemoradiotherapy (nCRT) followed by total mesorectal excision (TME). Surgery is conventionally performed approximately 6-8 weeks after nCRT. This study aimed to determine the effect on outcomes of extending this interval.

METHODS

A systematic search was performed for studies reporting oncological results that compared the classical interval (less than 8 weeks) from the end of nCRT to TME with a minimum 8-week interval in patients with LARC. The primary endpoint was the rate of pathological complete response (pCR). Secondary endpoints were recurrence-free survival, local recurrence and distant metastasis rates, R0 resection rates, completeness of TME, margin positivity, sphincter preservation, stoma formation, anastomotic leak and other complications. A meta-analysis was performed using the Mantel-Haenszel method.

RESULTS

Twenty-six publications, including four RCTs, with 25 445 patients were identified. A minimum 8-week interval was associated with increased odds of pCR (odds ratio (OR) 1·41, 95 per cent c.i. 1·30 to 1·52; P < 0·001) and tumour downstaging (OR 1·18, 1·05 to 1·32; P = 0·004). R0 resection rates, TME completeness, lymph node yield, sphincter preservation, stoma formation and complication rates were similar between the two groups. The increased rate of pCR translated to reduced distant metastasis (OR 0·71, 0·54 to 0·93; P = 0·01) and overall recurrence (OR 0·76, 0·58 to 0·98; P = 0·04), but not local recurrence (OR 0·83, 0·49 to 1·42; P = 0·50).

CONCLUSION

A minimum 8-week interval from the end of nCRT to TME increases pCR and downstaging rates, and improves recurrence-free survival without compromising surgical morbidity.

Predictors and Risk Factors of Pathologic Complete Response Following Neoadjuvant Chemoradiotherapy for Rectal Cancer: A Population-Based Analysis

Background: Patients with rectal cancer who achieve pathologic complete response (pCR) after neoadjuvant chemoradiotherapy (nCRT) may have a better prognosis and may be eligible for non-operative management. The aim of this research was to identify variables for predicting pCR in rectal cancer patients after nCRT and to define clinical risk factors for poor outcome after pCR to nCRT and radical resection in rectal cancer patients. Methods: A retrospective review was performed using the Surveillance, Epidemiology, and End Results (SEER) database from 2004 to 2013. Non-metastatic rectal cancer patients who received radical resection after neoadjuvant chemoradiotherapy were included in this study. Multivariate analysis of the association between clinicopathological characteristics and pCR was performed, and a logistic regression model was used to identify independent predictors for pCR. A nomogram based on the multivariate logistics regression was built with decision curve analyses to evaluate the clinical usefulness. Results: A total of 6,555 patients were included in this study. The proportion of patients with pCR was 20.5% (n = 1,342). The nomogram based on multivariate logistic regression analysis showed that clinical T4 and N2 stages were the most significant independent clinical predictors for not achieving pCR, followed by mucinous adenocarcinoma and positive pre-treatment serum CEA results. The 3-year overall survival rate was 92.4% for those with pCR and 88.2% for those without pCR. Among all the pCR patients, mucinous adenocarcinoma patients had the worst survival, with a 3-year overall survival rate of 67.5%, whereas patients with common adenocarcinoma had an overall survival rate of 93.8% (P < 0.001). Univariate and multivariate analyses showed that histology and clinical N2 stage were independent risk factors. Conclusion: Mucinous adenocarcinoma, positive pre-treatment serum CEA results, and clinical T4 and N2 stages may impart difficulty for patients to achieve pCR. Mucinous adenocarcinoma and clinical N2 stage might be indicative of a prognostically unfavorable biological tumor profile with a greater propensity for local or distant recurrence and decreased survival.

Pretreatment Tumor Thickness as a Predictor of Pathologic Complete Response to Neoadjuvant Chemoradiation Therapy for Stage II/III Rectal Adenocarcinoma

OBJECTIVES

To evaluate pretreatment tumor thickness in predicting pathologic complete response (pCR) of stage II/III rectal adenocarcinoma to neoadjuvant chemoradiation (chemoradiotherapy [CRT]).

METHODS

We retrospectively analyzed 185 patients who were diagnosed with stage II or III rectal adenocarcinoma from January 2011 to July 2013 and treated with neoadjuvant intensity-modulated radiation therapy (45 Gy in 1.8-Gy fractions to pelvis and 50 Gy in 2-Gy fractions to rectal tumor as an integrated boost) or 3 dimensionally conformal radiation therapy (45 Gy in 1.8-Gy fractions to pelvis followed by an additional 5.4-Gy to rectal tumor) concurrently with two 3-week cycles of chemotherapy (oxaliplatin 130 mg/m on day 1 and capecitabine 825 mg/m, twice per day from day 1 to 14, cycle 2 starts on week 4). One week after CRT, 36% patients received 1 more cycle of the above chemotherapy and 55% received 1 to 2 cycles of FOLFOX6. Tumor response was categorized as pCR and non-pCR. Tumor thickness measured on magnetic resonance imaging was collected. A multivariate logistic regression model was used to evaluate the association of potential predictors and pCR.

RESULTS

Thirty-eight patients (20.5%) reached pCR. Multivariate analysis found the pretreatment tumor thickness to be associated with higher probability of pCR after adjusting for radiation therapy-surgery interval time and pretreatment carcino-embryonic antigen level. The pretreatment carcino-embryonic antigen level was associated with pCR in the univariate analysis but lost the association in the multivatiate model. The pretreatment T or N stage, tumor volume, distance from tumor to anal verge, craniocaudal length of tumor, radiation therapy technique, and patient age and sex were not associated with pCR.

CONCLUSIONS

We concluded that pretreatment tumor thickness is an independent predictor for pCR of stage II/III rectal adenocarcinoma to the neoadjuvant CRT.

Cross-Sectional Study on MRI Restaging After Chemoradiotherapy and Interval to Surgery in Rectal Cancer: Influence on Short- and Long-Term Outcomes

Background

The time interval between CRT and surgery in rectal cancer patients is still the subject of debate. The aim of this study was to first evaluate the nationwide use of restaging magnetic resonance imaging (MRI) and its impact on timing of surgery, and, second, to evaluate the impact of timing of surgery after chemoradiotherapy (CRT) on short- and long-term outcomes.

Methods

Patients were selected from a collaborative rectal cancer research project including 71 Dutch centres, and were subdivided into two groups according to time interval from the start of preoperative CRT to surgery (< 14 and ≥ 14 weeks).

Results

From 2095 registered patients, 475 patients received preoperative CRT. MRI restaging was performed in 79.4% of patients, with a median CRT–MRI interval of 10 weeks (interquartile range [IQR] 8–11) and a median MRI–surgery interval of 4 weeks (IQR 2–5). The CRT–surgery interval groups consisted of 224 (< 14 weeks) and 251 patients (≥ 14 weeks), and the long-interval group included a higher proportion of cT4 stage and multivisceral resection patients. Pathological complete response rate (n = 34 [15.2%] vs. n = 47 [18.7%], p = 0.305) and CRM involvement (9.7% vs. 15.9%, p = 0.145) did not significantly differ. Thirty-day surgical complications were similar (20.1% vs. 23.1%, p = 0.943), however no significant differences were found for local and distant recurrence rates, disease-free survival, and overall survival.

Conclusions

These real-life data, reflecting routine daily practice in The Netherlands, showed substantial variability in the use and timing of restaging MRI after preoperative CRT for rectal cancer, as well as time interval to surgery. Surgery before or after 14 weeks from the start of CRT resulted in similar short- and long-term outcomes.

Electronic supplementary material

The online version of this article (10.1245/s10434-018-07097-7) contains supplementary material, which is available to authorized users.

Efficacy and safety of consolidation chemotherapy during the resting period in patients with local advanced rectal cancer

It remains controversial as to whether a long interval between neoadjuvant chemoradiotherapy (NCRT) and surgery may provide clinical benefits for patients with local advanced rectal cancer (LARC). The addition of consolidation chemotherapy during the resting period was recently considered as a treatment option. The present study aimed to verify the efficacy and safety of consolidation chemotherapy during the resting period in patients with LARC. A total of 156 patients with local advanced stage T3-4N0-2 rectal cancer were enrolled between January 2010 and July 2016. Patients were divided into two groups, those who received consolidation chemotherapy prior to surgery (n=76) and the control group who did not (n=80). Multivariate logistic regression and the Kaplan-Meier method were used to explore the predictors of pathological complete response (pCR) and survival. The demographic and tumor characteristics were comparable between the two groups. The consolidation group yielded significantly higher pCR and near pCR rates compared with the control group (P=0.015). Patients in the consolidation group who also underwent standard adjuvant chemotherapy displayed improved 3-year disease-free survival (DFS) compared with the control group (P=0.036). Notably, the addition of consolidation chemotherapy between NCRT and surgery did not significantly increase the incidence of surgical complications and grade 3 or 4 toxicities when compared with the control group. Consolidation chemotherapy was associated with increased pCR/near pCR rates and improved 3-year DFS, and displayed a manageable safety profile. The present study provided primary evidence for the efficacy and safety of consolidation chemotherapy in LARC. Further prospective studies are warranted in the future to verify these results.

Clinical and molecular diagnosis of pathologic complete response in rectal cancer: an update

INTRODUCTION

The standard of care for locally advanced rectal cancer includes neoadjuvant chemoradiation with subsequent total mesorectal excision. This approach has shown various degrees of response to neoadjuvant chemoradiation (ranging from complete response to further tumor growth), which have substantial prognostic and therapeutic implications. A total regression of the tumor is a predictor of superior oncologic outcomes compared with partial responders and non-responders. Further, this concept has opened the possibility of nonoperative strategies for complete responders and explains the widespread research interest in finding clinical, radiographic, pathologic, and biochemical parameters that allow for identification of these patients. Areas covered: The present review evaluates the most recent efforts in the literature to identify predictors of patients likely to achieve a complete response following neoadjuvant treatment for the management of rectal cancer. This includes clinical predictors of pathologic complete response such as tumor location, size, and stage, molecular predictors such as tumor biology and microRNA, serum biomarkers such as carcinoembryogenic antigen and nomograms. Expert commentary: There has been significant progress in our ability to predict pathological complete response. However, more high-quality research is still needed to use this concept to confidently dictate clinical management.

Randomized clinical trial of short or long interval between neoadjuvant chemoradiotherapy and surgery for rectal cancer

BACKGROUND

The optimal timing of surgery following preoperative chemoradiotherapy (CRT) is controversial. This trial aimed to compare pathological complete response (pCR) rates obtained after an interval of 8 weeks or less versus more than 8 weeks.

METHODS

Patients with locally advanced rectal adenocarcinoma situated within 12 cm of the anal verge (T3-4 or N+ disease) were randomized to undergo total mesorectal excision (TME) within 8 weeks (classical interval, CI group) or after 8 weeks (long interval, LI group) following CRT.

RESULTS

Among the 327 included patients (CI 160, LI 167), the pCR rate was significantly higher in the LI group than in the CI group (10·0 versus 18·6 per cent; P = 0·027). The highest pCR rate (29 per cent) was observed between 10 and 11 weeks. There was statistically significant disease regression in the LI group, with better stage (P = 0·004) and T category (P = 0·001) than in the CI group. There was no significant difference in surgical quality (rates of tumour-positive margins, TME quality, anastomotic leakage and intraoperative perforation) between the groups. The overall morbidity rate was 22·5 per cent in the CI group and 19·8 per cent in the LI group (P = 0·307). Regression analysis including sex, age, clinical stage, tumour location, tumour differentiation, TME quality, concomitant chemotherapy and interval to surgery revealed no statistically significant predictors of pCR.

CONCLUSION

Disease regression and pCR rate are increased with an interval between CRT and surgery exceeding 8 weeks. Registration number: NCT03287843 (http://www.clinicaltrials.gov).

Systemic immune response induced by oxaliplatin-based neoadjuvant therapy favours survival without metastatic progression in high-risk rectal cancer

Background

Systemic failure remains a challenge in rectal cancer. We investigated the possible systemic anti-tumour immune activity invoked within oxaliplatin-based neoadjuvant therapy.

Methods

In two high-risk patient cohorts, we assessed the circulating levels of the fms-like tyrosine kinase 3 ligand (Flt3L), a factor reflecting both therapy-induced myelosuppression and activation of tumour antigen-presenting dendritic cells, at baseline and following induction chemotherapy and sequential chemoradiotherapy, both modalities containing oxaliplatin. The primary end point was progression-free survival (PFS).

Results

In both cohorts, the median Flt3L level was significantly higher at completion of each sequential modality than at baseline. The 5-year PFS (most events being metastatic progression) was 68% and 71% in the two cohorts consisting of 33% and 52% T4 cases. In the principal cohort, a high Flt3L level following the induction chemotherapy was associated with low risk for a PFS event (HR: 0.15; P < 0.01). These patients also had available dose scheduling and toxicity data, revealing that oxaliplatin dose reduction during chemoradiotherapy, undertaken to maintain compliance to the radiotherapy protocol, was associated with advantageous PFS (HR: 0.47; P = 0.046).

Conclusion

In high-risk rectal cancer, oxaliplatin-containing neoadjuvant therapy may promote an immune response that favours survival without metastatic progression.

Watch-and-Wait as a Therapeutic Strategy in Rectal Cancer

Purpose of Review

Pathological complete response is seen in approximately one fifth of rectal cancer patients following neoadjuvant chemoradiation. Since these patients have excellent oncological outcomes, there has been a rapidly growing interest in organ preservation for those who develop a clinical complete response. We review the watch-and-wait strategy and focus on all aspects of this hot topic, including who should be considered for this approach, how should we identify treatment response and what are the expected outcomes.

Recent Findings

The major challenges in interpreting the data on watch-and-wait are the significant heterogeneity of patients selected for this approach and of methods employed to identify them. The evidence available comes mostly from retrospective cohort studies, but has shown good oncological outcomes, including the rate of successful salvage surgery, locoregional control and overall survival.

Summary

There is currently not enough and not robust enough evidence to support watch-and-wait as a standard approach, outside a clinical trial, for patients achieving clinical complete response following neoadjuvant chemoradiation. Furthermore, there is a lack of data on long-term outcomes. However, the results we have so far are promising, and there is therefore an urgent need for randomised control studies such as the TRIGGER trial to confirm the safety of this strategy.

Timing of surgery after neoadjuvant chemotherapy for gastric cancer: Impact on outcomes

AIM

To evaluate whether the neoadjuvant chemotherapy (NACT)-surgery interval time significantly impacts the pathological complete response (pCR) rate and long-term survival.

METHODS

One hundred and seventy-six patients with gastric cancer undergoing NACT and a planned gastrectomy at the Chinese PLA General Hospital were selected from January 2011 to January 2017. Univariate and multivariable analyses were used to investigate the impact of NACT-surgery interval time (< 4 wk, 4-6 wk, and > 6 wk) on pCR rate and overall survival (OS).

RESULTS

The NACT-surgery interval time and clinician T stage were independent predictors of pCR. The interval time > 6 wk was associated with a 74% higher odds of pCR as compared with an interval time of 4-6 wk (P = 0.044), while the odds ratio (OR) of clinical T₃vs clinical T₄ stage for pCR was 2.90 (95%CI: 1.04-8.01, P = 0.041). In Cox regression analysis of long-term survival, post-neoadjuvant therapy pathological N (ypN) stage significantly impacted OS (N₀vs N₃: HR = 0.16, 95%CI: 0.37-0.70, P = 0.015; N₁vs N₃: HR = 0.14, 95%CI: 0.02-0.81, P = 0.029) and disease-free survival (DFS) (N₀vs N₃: HR = 0.11, 95%CI: 0.24-0.52, P = 0.005; N₁vs N₃: HR = 0.17, 95%CI: 0.02-0.71, P = 0.020). The surgical procedure also had a positive impact on OS and DFS. The hazard ratio of distal gastrectomy vs total gastrectomy was 0.12 (95%CI: 0.33-0.42, P = 0.001) for OS, and 0.13 (95%CI: 0.36-0.44, P = 0.001) for DFS.

CONCLUSION

The NACT-surgery interval time is associated with pCR but has no impact on survival, and an interval time > 6 wk has a relatively high odds of pCR.