Rectal Cancer Downstaging is Significantly Improved with Different Regimens of Total Neoadjuvant Therapy

Perioperative Complications After Proctectomy for Rectal Cancer: Does Neoadjuvant Regimen Matter?

OBJECTIVE

Investigate the association between neoadjuvant treatment strategy and perioperative complications in patients undergoing proctectomy for nonmetastatic rectal cancer.

SUMMARY OF BACKGROUND DATA

Neoadjuvant SC-TNT is an alternative to neoadjuvant CRT for rectal cancer. Some have argued that short-course radiation and extended radiation-to-surgery intervals increase operative difficulty and complication risk. However, the association between SC-TNT and surgical complications has not been previously investigated.

METHODS

This single-center retrospective cohort study included patients undergoing total mesorectal excision for nonmetastatic rectal cancer after SC-TNT or CRT between 2010 and 2018. Univariate analysis of severe POM and multiple secondary outcomes, including overall POM, intraoperative complications, and resection margins, was performed. Logistic regression of severe POM was also performed.

RESULTS

Of 415 included patients, 156 (38%) received SC-TNT and 259 (62%) received CRT. The cohorts were largely similar, though patients with higher tumors (69.9% vs 47.5%, P < 0.0001) or node-positive disease (76.9% vs 62.6%, P = 0.004) were more likely to receive SC-TNT. We found no difference in incidence of severe POM (9.6% SC-TNT vs 12.0% CRT, P = 0.46) or overall POM (39.7% SC-TNT vs 37.5% CRT, P = 0.64) between cohorts. Neoadjuvant regimen was also not associated with a difference in severe POM (odds ratio 0.42, 95% confidence interval 0.04-4.70, P = 0.48) in multivariate analysis. There was no significant association between neoadjuvant regimen and any secondary outcome.

CONCLUSION

In rectal cancer patients treated with SC-TNT and proctectomy, we found no significant association with POM compared to patients undergoing CRT. SC-TNT does not significantly increase the risk of POM compared to CRT.

Total neoadjuvant therapy in patients with locally advanced rectal cancer: A tertiary medical center experience

The current standard of care for locally advanced rectal cancer (LARC) includes preoperative chemoradiation, followed by total mesorectal excision and adjuvant chemotherapy. This multimodality treatment improves local control but is associated with low compliance rates without clear beneficial effects on overall survival (OS) and distant metastasis. In this retrospective study, the charts of patients diagnosed with cT3/4 or cT2-node-positive rectal cancer between January 2011 and June 2019 were reviewed. The chemoradiation therapy (CRT) group received a long course of CRT with capecitabine followed by surgery and adjuvant chemotherapy. The total neoadjuvant therapy (TNT) group received 6 cycles mFOLFOX and a short course of radiation therapy followed by surgery. A total of 81 patients were included, among which 55 (67.9%) received CRT and 26 (32.1%) received TNT. In the CRT group, 15 (27.3%) patients achieved pathologic complete response (pCR) compared with 10 (38.5%) in the TNT group (P=0.22). A total of 19 (35.8%) cases in the CRT group downstaged to pT0N0 or pT1N0 compared with 11 (42.3%) in the TNT group (P=0.33). The 2-year disease-free survival (DFS) rate was 81.0% in the TNT group and 84.0% in the CRT group (P=0.15). Out of 55 patients in the CRT group, 30 patients received adjuvant chemotherapy, 22 (40.0% of CRT cases) of which completed a full course. All 26 patients in the TNT group received neoadjuvant chemotherapy, where 22 (84.6%) patients took a full course (P<0.001). In conclusion, the present study revealed that patients treated with TNT were more compliant to chemotherapy than those treated with CRT. A numerically higher pCR rate, and nodal and tumor downstaging were noted in the TNT group without significance. No difference was noted in the 2-year DFS. Longer follow-up is required.

The concept and use of the neoadjuvant rectal score as a composite endpoint in rectal cancer

There is no universally accepted instrument to use as a validated surrogate endpoint for overall survival in phase 2 and phase 3 multimodal rectal cancer trials using chemoradiotherapy. Efforts are hampered by the inaccuracy of clinical TNM staging, the variability of indications for neoadjuvant treatment, and diverse definitions of tumour regression grade. Pathological complete response is commonly used, but fails to capture information from the majority of patients. The neoadjuvant rectal score categorises response and downstaging from the entire trial population to identify whether or not a novel treatment group in a chemoradiation trial is superior by predicting overall survival outcomes. Additionally, the neoadjuvant rectal score assesses the difference between initial clinical and pathological T stage and the presence or absence of nodal involvement after treatment. The neoadjuvant rectal score has been conceptually, but incompletely, statistically validated by two independent trial datasets. However, a fundamental weakness of the score is that no preoperative phase 3 trials in locally advanced rectal cancer in the past 20 years have provided a significant benefit in overall survival to statistically validate the neoadjuvant rectal score as a surrogate endpoint for overall survival. We review the robustness, practical value, applicability, generalisability, advantages, and disadvantages of the neoadjuvant rectal score as a surrogate endpoint for overall survival and recommend how this score could be improved and be acceptable as a standard endpoint in studies investigating neoadjuvant chemotherapy and chemoradiation in patients with rectal cancer.