Preoperative versus postoperative chemoradiotherapy in stage T3, N0 rectal cancer

SIRT1: a novel regulator in colorectal cancer

The class-III histone deacetylase SIRT1 is the most extensively investigated sirtuin deacetylase. It is resistant to the broad deacetylase inhibitor trichostatin A and depends on oxidized nicotinamide adenine nucleotide (NAD+). SIRT1 plays a crucial role in the tumorigenesis of numerous types of cancers, including colorectal cancer (CRC). Accumulating evidence indicates that SIRT1 is a therapeutic target for CRC; however, the function and underlying mechanism of SIRT1 in CRC still need to be elucidated. Herein, we provide a detailed and updated review to illustrate that SIRT1 regulates many processes that go awry in CRC cells, such as apoptosis, autophagy, proliferation, migration, invasion, metastasis, oxidative stress, resistance to chemo-radio therapy, immune evasion, and metabolic reprogramming. Moreover, we closely link our review to the clinical practice of CRC treatment, summarizing the mechanisms and prospects of SIRT1 inhibitors in CRC therapy. SIRT1 inhibitors as monotherapy in CRC or in combination with chemotherapy, radiotherapy, and immune therapies are comprehensively discussed. From epigenetic regulation to its potential therapeutic effect, we hope to offer novel insights and a comprehensive understanding of SIRT1's role in CRC.

Effects of Neoadjuvant Radiotherapy on Postoperative Complications in Rectal Cancer: A Meta-Analysis

Objective

Neoadjuvant radiotherapy (nRT) is an important treatment approach for rectal cancer. The relationship, however, between nRT and postoperative complications is still controversial. Here, we conducted a meta-analysis to evaluate such concerns.

Methods

The electronic literature from 1983 to 2021 was searched in PubMed, Embase, and Web of Science. Postoperative complications after nRT were included in the meta-analysis. The pooled odds ratio (OR) was calculated by the random-effects model. Statistical analysis was conducted by Review Manager 5.3 and STATA 14.

Results

A total of 23,723 patients from 49 studies were included in the meta-analysis. The pooled results showed that nRT increased the risk of anastomotic leakage (AL) compared to upfront surgery (OR = 1.23; 95% CI, 1.07-1.41; p=0.004). Subgroup analysis suggested that both long-course (OR = 1.20, 95% CI 1.03-1.40; p=0.02) and short-course radiotherapy (OR = 1.25, 95% CI, 1.02-1.53; p=0.04) increased the incidence of AL. In addition, nRT was the main risk factor for wound infection and pelvic abscess. The pooled data in randomized controlled trials, however, indicated that nRT was not associated with AL (OR = 1.01; 95% CI 0.82-1.26; p=0.91).

Conclusions

nRT may increase the risk of AL, wound infection, and pelvic abscess compared to upfront surgery among patients with rectal cancer.

Re-evaluation of controversial issues in the treatment of cT3N0-2 rectal cancer: a 10-year cohort analysis using propensity-score matching

BACKGROUND

Although neoadjuvant treatment is thought to provide optimal local control for stage II and III rectal cancers, many patients have been reported cured by total mesorectal excision (TME), alone or with additional chemotherapy (CTX).

METHODS

This study retrospectively evaluated outcomes in 2643 patients with cT3N0-2 rectal cancers undergoing curative TME during 2005-2015. Recurrence and survival outcomes were measured in three propensity-score matched groups, consisting of patients who underwent preoperative chemoradiotherapy (CRT) with postoperative CTX (NAPOC), postoperative CRT (POCRT), and exclusively postoperative CTX (EPOCT).

RESULTS

Near-complete or complete TME was conducted in more than 95.9% of patients and 80% of scheduled dose of postoperative CTX was completed in 99%. Except for higher SR rate in the POCRT group than the NAPOC group (p = 0.008), 5-year cumulative local and systemic recurrence (LR and SR) rates were 4.9% and 15.2% for cT3N0, and 4.2% and 21% for cT3N1-2 patients (LR, p = 0.703; SR, 0.065), respectively, with no significant differences associated with treatment exposure (p = 0.11-1). The 5-year cumulative disease-free (75.6% vs 65.7%, p = 0.018) and overall survival (87.1% vs 79.4%, p = 0.018 each) rates were higher in the NAPOC group than the POCRT group with cT3N1-2. However, any significant survival differences were not identified between the NAPOC and EPOCT groups according to tumor sub-stages or locations (p = 0.395-0.971).

CONCLUSIONS

We found any treatment modalities including competent TME and postoperative adjuvant CTX efficiently reducing LR generating robust survival outcome in the propensity-matched cohorts, demanding further randomized controlled trials by clinical sub-stages II-III.

Oral microbiota affects the efficacy and prognosis of radiotherapy for colorectal cancer in mouse models

Radiotherapy is inevitably intertwined with various side effects impairing the quality of life of cancer patients. Here, we report the possibility that alterations of the oral microbiota influence the therapeutic efficacy and prognosis of radiotherapy for primary rectal cancer and colorectal cancer (CRC) liver metastases that pathologically disrupt gastrointestinal integrity and function. 16S rRNA sequencing shows that oral microbiota alterations change the gut bacterial composition within tumors but not in adjacent peritumor tissues in CRC mouse models. Specifically, buccal Fusobacterium nucleatum migrates to the CRC locus and impairs the therapeutic efficacy and prognosis of radiotherapy. Administration of a specific antibiotic, metronidazole, abrogates the adverse effects of oral microbiome fluctuation on radiotherapy for CRC. The oral microbiota were also associated with radiation-induced intestinal injury via intestinal microbes. Our findings demonstrate that the oral microbiome in synergy with its intestinal counterparts impinges on the efficacy and prognosis of radiotherapy for CRC.

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.

Capecitabine versus 5-fluorouracil in neoadjuvant chemoradiotherapy of locally advanced rectal cancer: A meta-analysis

BACKGROUND

The differences in efficacy between capecitabine and 5-fuorouracil (5-FU) in neoadjuvant chemoradiotherapy (CRT) of locally advanced rectal cancer (LARC) are not well recognized. We performed this meta-analysis to analyze the effect of capecitabine and 5-FU on neoadjuvant CRT to more accurately understand the differences between the 2 drugs.

METHODS

MEDLINE, EMBASE, Cochrane Library, China National Knowledge Infrastructure, and Wanfang Database were performed to identify all published studies investigating the efficacy of capecitabine in neoadjuvant CRT of LARC versus 5-FU before August, 2017. Primary endpoint was the odds ratio (OR) for improving pathological complete response (pCR) rate of patients with LARC. Secondary endpoints were the ORs of efficiency for downstaging tumor and increasing R0 resection in patients with LARC. Safety analyses were also performed. The OR was the principal measurement of effect, which was calculated as capecitabine group versus 5-FU group, and was presented as a point estimate with 95% confidence intervals (CIs). All calculations and statistical tests were performed using RevMan 5.3 software.

RESULTS

In all, 2916 patients with LARC enrolled in the 10 studies were divided into capecitabine group (n = 1451) and 5-FU group (n = 1465). The meta-analysis showed that capecitabine improved pCR (OR 1.34, 95% CI 1.10-1.63), and R0 resection rate (OR 1.92, 95% CI 1.10-3.36). There were no statistically significant differences either in overall downstaging rate (OR 1.31, 95% CI 0.79-2.16) or in the tumor downstaging rate (OR 1.24, 95% CI 0.79-1.92), but there was a significant difference of the nodal downstaging rate between the 2 groups (OR 1.68, 95% CI 1.11-2.54). There was no statistically significant difference in sphincter preservation rate between the 2 groups (OR 1.36, 95% CI 0.96-1.92). No obvious safety concerns about mortality and complications were raised in these studies. There were no statistically significant differences in 3-year disease-free-survival (OR 1.29, 95% CI 0.75-2.20), and in grade 3 to 4 acute toxicity during CRT (OR 0.63, 95% CI 0.31-1.30).

CONCLUSIONS

Compared with 5-FU-based neoadjuvant CRT, capecitabine-based neoadjuvant CRT can safely improve pCR, nodal down-staging, ad R0 resection of patients with LARC.

The clinicopathological and prognostic value of programmed death-ligand 1 in colorectal cancer: a meta-analysis

INTRODUCTION

Programmed death-ligand 1 (PD-L1) is reportedly expressed in colorectal tumors. However, the prognostic role of PD-L1 in colorectal cancer (CRC) remains controversial. Therefore, we performed a meta-analysis to investigate the clinicopathological and prognostic impact of PD-L1 in CRC.

METHODS

A comprehensive search in PubMed, Embase, the Cochrane Library, Web of Science and the ClinicalTrials.gov for publications about PD-L1 expression in colorectal cancer was done. The correlation between PD-L1 expression and clinicopathological features or survival outcomes was analyzed by odds ratios (OR) or hazard ratios (HR), at 95% confidence intervals (CI).

RESULTS

The results show that the pooled HR of (1.34, 95% CI 1.02-1.65, p = 0.01) indicated the association of PD-L1 expression with overall survival (OS) in CRC patients. Meanwhile, the expression of PD-L1 was positively correlated with the lymph node metastasis (OR: 0.70, 95% CI 0.51-0.95, p = 0.00), gender (OR: 0.86, 95% CI 0.76-0.98, p = 0.05) and tumor location (OR: 1.39, 95% CI 1.14-1.71, p = 0.12).

CONCLUSIONS

These results suggest that high expression of PD-L1 is associated with low OS in CRC. High PD-L1 expression may act as a negative factor for patients with CRC and help to identify patients suitable for anticancer therapy.

Comparative Outcomes of Preoperative Chemoradiotherapy and Selective Postoperative Chemoradiotherapy in Clinical Stage T3N0 Low and Mid Rectal Cancer

Purpose/aim: Preoperative chemoradiotherapy (pre-CRT) and total mesorectal excision (TME) have become the standard of care for patients with locally advanced rectal cancer (LARC). Nevertheless, it is a controversial issue whether pre-CRT in cT3N0M0 patients would result in potential overtreatment. Materials and methods: In total, 183 clinical stage IIA rectal cancer patients treated with and without pre-CRT between 2011 and 2014 were retrospectively analyzed. Capecitabine/FOLFOX/CAPOX chemotherapy was co-administered with preoperative radiotherapy. Surgical resection with laparoscopic or open TME was conducted 8-12 weeks after completion of the pre-CRT. Postoperative radiotherapy was routinely given to patients with pT4 lesion or circumferential margin (CRM) and/or distal resection margin (DRM) involvement. Results: In total, 108 (59%) patients received pre-CRT and 75 (41%) underwent surgery first. The pre-CRT patients presented with less-advanced pathological T stage tumors compared with the surgery-first patients (p < 0.001). However, the pathological N stage was not significantly different between the two groups (p = 0.065). The 3-year overall survival (OS), disease-free survival (DFS), and 2-year local recurrence (LR) rate were similar in the pre-CRT and surgery-first patients (88.4 versus 88.7%, p = 0.552; 79.6 versus 83.3%, p = 0.797; 2.8 versus 2.7%, p = 0.960, respectively). Cox regression analysis showed that pN stage and CRM/DRM involvement were independently correlated with an unfavorable DFS. Conclusions: In this study, the omission of pre-CRT in cT3N0M0 patients did not translate into a worse oncological outcome. Postoperative radiotherapy should remain a standard option for patients with CRM/DRM involvement and pathological T4 tumors. A generalized indication for pre-CRT in cT3N0 patients is likely to result in overtreatment.

The survival and clinicopathological differences between patients with stage IIIA and stage II rectal cancer: An analysis of 12,036 patients in the SEER database

BACKGROUND

Stage IIIA rectal cancer has distinctive oncological features, including limited depth of intestinal wall invasion and early regional lymph node metastasis. We aim to compare survival outcomes and clinicopathological features for stage IIIA rectal cancer with those for stage II rectal cancer.

METHODS

We analyzed patients with stage II or stage IIIA rectal cancer treated with surgery without receiving preoperative radiotherapy based on data from the US Surveillance, Epidemiology, and End Results (SEER) database between 1988 and 2003. Survival curves were plotted using the Kaplan-Meier method. Multivariate Cox proportional analyses were utilized to analyze independent prognostic factors for cancer-specific survival (CSS).

RESULTS

We included 12,036 rectal cancer patients (10,132 stage II and 1,904 stage IIIA) from the SEER database. Patients with stage IIIA rectal cancer had smaller tumor size than patients with stage II rectal cancer. A multivariate analysis suggested that compared with patients with stage IIIA rectal cancer, patients with stage II disease were more likely to have more unfavorable CSS (HR 1.195, 95% CI 1.079-1.324, p=0.001). When stage II rectal cancer was further analyzed as stage IIA, IIB and IIC rectal cancer, the multivariate analysis indicated that compared with patients with stage IIIA rectal cancer, patients with stage IIA rectal cancer (HR 1.113, 95% CI 1.003-1.235, p=0.044), stage IIB rectal cancer (HR 1.493, 95% CI 1.267-1.758, p<0.001) and stage IIC rectal cancer (HR 2.712, 95% CI 2.319-3.171, p<0.001) were also more likely to exhibit more unfavorable CSS.

CONCLUSIONS

Patients with stage IIIA rectal cancer had more favorable survival outcomes and smaller tumor size compared with patients with stage II rectal cancer.

Short-course neoadjuvant chemoradiotherapy and surgery are beneficial in Chinese patients: A retrospective study

Preoperative neoadjuvant chemoradiotherapy (NACR) is used to reduce tumor size for easier resection or improved resectability rates. Considering the difficulties regarding health insurance and health resources in China, an evidence-based short-course neoadjuvant chemoradiotherapy with surgery to cure patients was performed. This study compared the postoperative effects between short-course neoadjuvant chemoradiotherapy and surgery and surgery without neoadjuvant chemoradiotherapy.The current retrospective study was based on a rectal cancer database, including 274 patients diagnosed with rectal cancer between January 2014 and October 2016. Data were analyzed with respect to curative rate, postoperative recovery indicators (times to nasogastric tube, urinary catheter, and drainage tube removal and times to first oral feeding and passing of flatus postsurgery), chemoradiotherapy-related indicators [white blood cell count (WBC) and carcinoembryonic antigen (CEA) levels], and adverse effects indicators, evaluated according to Common Terminology Criteria for Adverse Events Version 4.0.There was no significant difference between the combined therapy and surgery groups (P > .05) in terms of radical resection rates and the times to urinary catheter removal and passing flatus (P > .05). Statistically significant differences (P < .05) in terms of earlier time for removal of the nasogastric and drainage tubes and time to first oral feeding were observed in the combined therapy group. The decreases in WBC and CEA levels in the combined therapy group were significantly greater than those in the surgery group 1 week after surgery (P < .05); after 1 month, the CEA decrease in the combined therapy group was significantly greater than that in the surgery group (P < .05). More patients in the combined therapy group experienced vomiting, indigestion, dehydration, oral mucositis, sensory neuritis, and alopecia compared with those in the surgery group 1 week after surgery (P < .05); after 1 month, only the incidence of alopecia was higher in the combined therapy group (P < .05).The combined therapy group demonstrated earlier postoperative recovery compared with the surgery group. Short-course neoadjuvant chemoradiotherapy with surgery may lead to postoperative treatment-related adverse effects of varying degrees; however, these adverse effects eventually improve with time.

Radiation dose intensification in pre-operative chemo-radiotherapy for locally advanced rectal cancer

BACKGROUND

To assess the role of radiation dose intensification with simultaneous integrated boost guided by 18-FDG-PET/CT in pre-operative chemo-radiotherapy (ChT-RT) for locally advanced rectal cancer.

METHODS

A prospective study was approved by the Internal Review Board. Inclusion criteria were: age >18 years old, World Health Organization performance status of 0-1, locally advanced histologically proven adenocarcinoma of the rectum within 10 cm of the anal verge, signed specific informed consent. High-dose volumes were defined including the hyper-metabolic areas of 18-FDG-PET/CT of primary tumor and the corresponding mesorectum and/or pelvic nodes with at least a standardized uptake values (SUV) of 5. A dose of 60 Gy/30 fractions was delivered. A total dose of 54 Gy/30 fractions was delivered to prophylactic areas. Capecitabine was administered concomitantly with RT for a dose of 825 mg/mq twice daily for 5 days/every week.

RESULTS

Between September 2011 and July 2015 fortypatients were recruited. At the time of the analysis, median follow up was 20 months (range 5-51). The median interval from the end of ChT-RT to surgery was 9 weeks (range 8-12). Thirty-seven patients (92.5 %) were submitted to sphincter preservation. Tumor Regression Grade (Mandard scale) was recorded as follows: grade 1 in 7 (17.5 %), grade 2 in 17 (42.5 %), grade 3 in 15 (37.5 %) and grade 4 in 1 (2.5 %). Post-surgical circumferential resection margin was negative in all patients. A tumor downstaging was reported in 62.5 % (95 % CI: 0.78-0.47). A nodes downstaging was registered in 85 % (95 % CI: 0.55-0.25). 18-FDG-PET/CT was not able to predict pCR. No correlation was found between pre-treatment SUV-max values and pCR. A metabolic tumor volume >127 cc was related to ypT ≥2 (p 0.01). Patients with TRG >2 had higher tumor lesion glycolysis values (p 0.05).

CONCLUSION

Preliminary results did not confirm some advantages in terms of primary tumor downstaging/downsizing compared to conventional schedules reported in historical series. The role of 18-FDG-PET/CT in neoadjuvant rectal cancer management needs to be confirmed in further investigations. Long terms results are necessary.

Comparison of 5-FU-based and Capecitabine-based Neoadjuvant Chemoradiotherapy in Patients With Rectal Cancer: A Meta-analysis

INTRODUCTION

The inconvenience of using infusion therapies resulted in the development of capecitabine (CA), an oral fluoropyrimidine. In this meta-analysis, we evaluated 10 studies that compared the efficacy and safety of an oral CA-based regimen with those of a continuous infusion 5-fluorouracil (5-FU) regimen for neoadjuvant chemoradiotherapy in patients with rectal cancer.

MATERIALS AND METHODS

The databases searched included Medline, Cochrane, EMBASE, and Google Scholar (until August 31, 2016). The primary outcome assessed was the rate of postoperative down-staging of the tumor and pathologic complete response. The secondary outcomes were disease-free survival (DFS) and overall survival (OS).

RESULTS

This meta-analysis (5 retrospective studies, 3 prospective studies, and 2 randomized controlled trials [RCTs]) compared the efficacy of the 5-FU arm (n = 757) to that of the CA arm (n = 719). There was no significant difference in tumor down-staging rate between the 2 regimens (RCTs/prospective studies: odds ratio [OR], 0.88; 95% confidence interval [CI], 0.65-1.20; P = .416; retrospective studies: OR, 0.84; 95% CI, 0.50-1.44; P = .534). There was also no significant difference in pathologic complete response (RCTs/prospective studies: OR, 0.80; 95% CI, 0.52-1.23; P = .304; retrospective studies: OR, 0.73; 95% CI, 0.48-1.12; P = .149), or survival rates (3-year, 5-year DFS, and 5-year OS rate) between the 2 groups. The CA group had a higher number of patients reporting diarrhea and hand-foot syndrome compared with the 5-FU group. The 5-FU group had a higher number of patients reporting mucositis compared with the CA group.

CONCLUSIONS

Our data suggested that oral CA was equivalent to continuous infusion 5-FU in the curative setting of rectal cancer during neoadjuvant chemoradiotherapy.

The short term feasibility of abdominoperineal resection with prostatectomy for locally advanced rectal cancer: open and laparoscopic cases report

Total pelvic exenteration is often selected for advanced rectal cancer with prostatic invasion. The aim of this study was to evaluate the short term feasibility of the abdominoperineal resection with prostatectomy for locally advanced rectal cancer. We performed abdominoperineal resection with prostatectomy for 3 patients with locally advanced rectal cancer, including 2 patients by totally laparoscopic procedure. Patients' background, intra- and postoperative factors and short-term prognosis were evaluated. All patients underwent complete resection of primary tumor with negative surgical margins. We could perform the surgery by both open and laparoscopic procedure in collaboration with urologist. There was no operation related mortality. One patient who was treated by open procedure had urinary anastomotic leakage. No patient had recurrenced, but one patient died of other disease. Our experience suggests that open or laparoscopic abdominoperineal resection with prostatectomy could be an alternative to total pelvic exenteration for the patients with rectal cancer invading the prostate. The collaboration with the urologist would be important to perform quality-controlled surgery.

Therapeutic results of abdominoperineal resection in the prone jackknife position for T3-4 low rectal cancers

OBJECTIVE

To evaluate the therapeutic results of abdominoperineal resections in the prone jackknife position for T3-4 low rectal cancers.

METHODS

From January 2002 to January 2011, 536 patients with T3-T4 low rectal cancer underwent abdominoperineal resection. Two hundred forty-three were treated in the Lloyd-Davies position and 293 in the prone jackknife position. Clinicopathological data and survival of the two groups were analyzed retrospectively.

RESULTS

Abdominoperineal resections in the prone jackknife position group were associated with significantly less blood loss (124 ± 50.68 vs 210.67 ± 83.32 ml, P < 0.001) and shorter operation times (3.10 ± 1.08 vs 3.82 ± 1.43 h, p = 0.010) than those in Lloyd-Davies position group. The total local recurrence rate is 8.4 % (45/536). The local recurrence rate in the prone jackknife position group was significantly lower than in the Lloyd-Davies position group (5.5 vs 11.9 %, P < 0.001). By multivariate regression analysis, depth of tumor invasion (P = 0.032), CRM (P < 0.001), and position (P = 0.015) were found to be independent risk factors for local recurrence. Multivariate Cox regression survival analysis, lymph node metastasis, and CRM (P < 0.001) were proven to be the major independent prognostic factors for T3-T4 low rectal cancer patients.

CONCLUSIONS

Abdominoperineal resection in the prone jackknife position for T3-T4 low rectal cancers is feasible and has a lower local recurrence.

Which is the best postoperative chemotherapy regimen in patients with rectal cancer after neoadjuvant therapy?

Background

There is no general agreement about whether patients who have already received neoadjuvant chemoradiotherapy need further postoperative chemotherapy based on 5-fluorouracil(5-FU) or 5-FU plus oxaliplatin.

Methods

Medicare beneficiaries from 1992 to 2008 with Union for International Cancer Control ypStages I to III primary carcinoma of the rectum who underwent 5-FU-based neoadjuvant chemoradiotherapy and surgery for curative intent were identified through the Surveillance, Epidemiology, and End Results (SEER)-Medicare-linked database. A Cox proportional hazards model and propensity score-matched techniques were used to evaluate the effect of treatment on survival.

Results

For patients with resected rectal cancer who have already received 5-FU-based neoadjuvant chemoradiotherapy, postoperative 5-FU-based chemotherapy did not prolong cancer-specific survival (CSS) in ypStage I (P = 0.960) and ypStage II (P = 0.134); however, it significantly improved the CSS in ypStage III (hazard ratio = 1.547, 95% CI = 1.101-2.173, P = 0.012). No significant differences in survival between the 5-FU group and oxaliplatin group were observed.

Conclusions

For patients with resected rectal cancer who have already received 5-FU-based neoadjuvant chemoradiotherapy, postoperative 5-FU-based chemotherapy prolongs the CSS of groups in ypStage III. Adding oxaliplatin to fluoropyrimidines in the postoperative chemotherapy did not improve the CSS for patients who received neoadjuvant chemoradiotherapy.

Electronic supplementary material

The online version of this article (doi:10.1186/1471-2407-14-888) contains supplementary material, which is available to authorized users.