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

Does a long interval between neoadjuvant chemoradiotherapy and surgery benefit the clinical outcomes of locally advanced rectal cancer? A systematic review and meta analyses

PURPOSE

The study aims to systematically evaluate the clinical efficacy after 8 weeks (long interval, LI) between neoadjuvant chemoradiotherapy and surgery for locally advanced rectal cancer.

METHODS

The PubMed database, EMBASE database, and the Cochrane Library (deadline: September 25, 2021) were searched to select clinical studies that compared two intervals between neoadjuvant chemoradiotherapy and surgery for locally advanced rectal cancer: after 8 weeks (long interval, LI) and within 8 weeks (short interval, SI). The included studies were screened and evaluated according to the inclusion and exclusion criteria, and meta-analysis was performed by RevMan 5.3 software.

RESULTS

Eighteen studies were included, with 9070 cases in the LI group and 14,207 cases in the SI group. The analysis results showed that the pathologic complete response (PCR) rate in the LI group was higher than that in the SI group (P < 0.00001). There was no significant difference in the R0 resection rate (P = 0.85), anal preservation rate (P = 0.89), morbidity rate (P = 0.60), anastomotic leakage rate (P = 0.06), operation time (P = 0.58), local recurrence rate (P = 0.56), distant metastasis rate (P = 0.32), or overall survival (OS) rate (P = 0.17) between the two groups.

CONCLUSION

A longer interval between neoadjuvant chemoradiotherapy and surgery can improve the PCR rate; however, it has no significant impact on the clinical efficacy or long-term prognosis. Due to some limitations in the number and quality of the studies, these findings still need to be further verified by multicenter, large-sample high-quality RCTs in the future.

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.

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.

The effect of time interval from chemoradiation to surgery on postoperative complications in patients with rectal cancer

BACKGROUND

A prolonged time interval between chemoradiation and total mesorectal excision (TME) may render more rectal cancer patients eligible for organ-sparing approaches but may also cause more pelvic fibrosis and surgical morbidity. We estimated the effect of time interval on postoperative complications and other surgical outcomes in rectal cancer patients.

METHODS

This is a population-based cohort study using data of the Dutch Colorectal Audit. Rectal cancer patients treated with chemoradiation followed by TME after an interval of 3-20 weeks were selected (n = 6,268). Time interval from completion of chemoradiation to TME was categorized into 3-6, 7-8, 9-10, 11-12 and 13-20 weeks. Outcomes included postoperative complication (any, and stratified by medical and surgical complications), reintervention, intraoperative complication, incomplete resection, positive circumferential margin (CRM) and pathological complete response (pCR). The interval of 7-8 weeks was the reference group.

RESULTS

Prolonged time intervals were not associated with a higher risk of a postoperative complication (any, surgical or medical), reintervention, and incomplete resection. Intraoperative complications were however more common after 11-12 weeks than after 7-8 weeks (odds ratio (OR) = 1.79, 95% confidence interval (CI) = 1.20-2.69). The interval of 9-10 weeks was associated with less CRM positive resections, and 9-10 and 13-20 weeks with more pCR (relative to 7-8 weeks, OR = 0.74, 95%CI = 0.56-0.98; OR = 1.28, 95%CI = 1.04-1.58; and OR = 1.33, 95%CI = 1.04-1.71, respectively).

CONCLUSIONS

Compared with 7-8 weeks, longer time intervals up to 13-20 weeks between chemoradiation and TME are not associated with more postoperative complications or more positive resection margins. Accordingly, prolonging the interval aiming for organ-sparing treatment is safe.

Optimal Interval to Surgery After Neoadjuvant Chemoradiotherapy in Rectal Cancer: A Systematic Review and Meta-analysis

This study aimed to evaluate the influence of a waiting interval of ≥ 8 weeks between the end of preoperative neoadjuvant chemoradiotherapy (nCRT) and surgery on the outcomes of patients with locally advanced rectal cancer. We conducted a comprehensive literature review of retrospective and prospective studies from PubMed, Embase, and Cochrane Library databases to investigate the length of the preoperative nCRT-surgery waiting interval and outcomes in patients with locally advanced rectal cancer. The primary outcome measure was pathologic complete response (pCR) rate. Secondary outcome measures included overall survival, disease-free survival, operative time, and the incidence of local recurrence, postoperative complications, anastomotic leakage, and sphincter-preserving surgery. Standardized mean differences and risk ratios were calculated. Thirteen studies involving 19,652 patients were included. The meta-analysis demonstrated that pCR was significantly increased in patients with locally advanced rectal cancer and a waiting interval of ≥ 8 weeks between preoperative nCRT and surgery compared to a waiting interval of < 8 weeks, or a waiting interval of > 8 weeks compared to ≤ 8 weeks (risk ratio = 1.25; 95% confidence interval, 1.16-1.35; P < .0001). There were no significant differences in overall survival, disease-free survival, operative time, or incidence of local recurrence, postoperative complications, or sphincter-preserving surgery. This study revealed that performing surgery after a waiting interval of ≥ 8 weeks after the end of preoperative nCRT is safe and efficacious for patients with locally advanced rectal cancer, significantly improving pCR without increasing operative time or incidence of postoperative complications, compared to a waiting interval of ≤ 8 weeks.