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

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.

Global variation in the long-term outcomes of ypT0 rectal cancers

BACKGROUND

Colorectal cancer mortality presents world-wide variation. In rectal cancers presenting a complete/nearly-complete tumor response (ypT0/ypTis) following neoadjuvant treatment, the features correlated to nodal metastases and relapses still need to be defined.

METHODS

An international cohort study enrolling ypT0/ypTis rectal cancers surgically treated from 2012 to 2017 was conducted. A propensity matching was used to balance nodal-positive and nodal-negative patients and statistical analyses were performed to investigate survivals, using a bootstrap model for internal validation. The features correlated with nodal metastasis were studied. Countries with participating centers were ranked using the World Bank (WBI), Human Development (HDI) and Global Gender Gap (GGG) indexes to compare survivals.

RESULTS

680 ypT0/ypTis from 52 European, Australian, Indian and American Institutions were analyzed. Mean follow-up was of 30.4 months. 96.5% were treated with total mesorectal excision, 7.2% were nodal-positive and 8.8% relapsed. Distal cancers (HR 0.71 95%CI: 0.56-0.91) and nodal metastasis and nodal metastasis (HR 3.85 95%CI:1.12-13.19) correlated with worse DFS, whereas a younger age was of borderline significance (HR 0.95 95%CI:0.91-0.99). The bootstrap analysis validated the model on 5000 repetitions. A short-course radiotherapy (OR 0.18 95%CI:0.09-0.37) correlated with the occurrence of nodal metastasis. Those countries classified in the low/medium-WBI, medium-HDI and lower-GGG ranks documented worse DFS curves (respectively p < 0.0001, p < 0.0001 and p 0.0002). However, the clinical stages were similar and patients from medium-HDI countries received more adjuvant chemotherapy than the others (p < 0.0001).

CONCLUSION

Sub-groups at risk for relapses and nodal metastasis were identified. A global variation exists also when benchmarking a rectal cancer complete regression.

Population-based study of morbidity risk associated with pathological complete response after chemoradiotherapy for rectal cancer

Background

Neoadjuvant chemoradiotherapy (nCRT) for locally advanced rectal cancer may induce a pathological complete response (pCR) but increase surgical morbidity due to radiation-induced fibrosis. In this study the association between pCR and postoperative surgical morbidity was investigated.

Methods

Patients in the Netherlands with rectal cancer who underwent nCRT followed by total mesorectal excision between 2009 and 2017 were included. Data were stratified into patients who underwent resection with creation of a primary anastomosis and those who had a permanent stoma procedure. The association between pCR and postoperative morbidity was investigated in univariable and multivariable logistic regression analyses.

Results

pCR was observed in 976 (12·2 per cent) of 8003 patients. In 3472 patients who had a primary anastomosis, the presence of pCR was significantly associated with surgical complications (122 of 443 (27·5 per cent) versus 598 of 3029 (19·7 per cent) in those without pCR) and anastomotic leak (35 of 443 (7·9 per cent) versus 173 of 3029 (5·7 per cent) respectively). Multivariable analysis also showed associations between pCR and surgical complications (adjusted odds ratio (OR) 1·53, 95 per cent c.i. 1·22 to 1·92) and pCR and anastomotic leak (adjusted OR 1·41, 1·03 to 2·05). Of 4531 patients with a permanent stoma, surgical complications were observed in 120 (22·5 per cent) of 533 patients with a pCR, compared with 798 (20·0 per cent) of 3998 patients with no pCR (adjusted OR 1·17, 0·94 to 1·46).

Conclusion

Patients with a pCR in whom an anastomosis was created were at increased risk of developing an anastomotic leak.