Aims of combined modality therapy in rectal cancer (M0)

Cholecystectomy Damages Aging-Associated Intestinal Microbiota Construction

The intestinal microbiome is essential in humans to maintain physiological balance and nutrition metabolism. Laparoscopic cholecystectomy due to gallstone disease and cholecystitis can cause intestinal microbial dysbiosis, and following bile acid metabolism dysfunction, positions the patient at high risk of colorectal cancer. However, little is known regarding intestinal microbiota characteristics in post-cholecystectomy patients. Here, we compared the microbial composition of cholecystectomy patients with that of a healthy population. We determined that cholecystectomy eliminated aging-associated fecal commensal microbiota and further identified several bile acid metabolism-related bacteria as contributors of colorectal cancer incidence via elevation of secondary bile acids.

Is neoadjuvant chemoradiation with dose-escalation and consolidation chemotherapy sufficient to increase surgery-free and distant metastases-free survival in baseline cT3 rectal cancer?

Patients with cT3 rectal cancer are less likely to develop complete response to neoadjuvant chemoradiation (nCRT) and still face significant risk for systemic relapse. In this setting, radiation (RT) dose-escalation and consolidation chemotherapy in "extended" nCRT regimens have been suggested to improve primary tumor response and decrease the risks of systemic recurrences. For these reasons we compared surgery-free and distant-metastases free survival among cT3 patients undergoing standard or extended nCRT.

METHODS

Patients with distal and non-metastatic T3 rectal cancer managed by nCRT were retrospectively reviewed. Patients undergoing standard CRT (50.4 Gy and 2 cycles of 5FU-based chemotherapy) were compared to those undergoing extended CRT (54 Gy and 6 cycles of 5FU-based chemotherapy). Patients were assessed for tumor response at 8-10 weeks. Patients with complete clinical response (cCR) underwent organ-preservation strategy (Watch & Wait). Patients were referred to salvage surgery in the event of local recurrence during follow-up. Cox's logistic regression was performed to identify independent features associated with improved surgery-free survival after cCR and distant-metastases-free survival.

RESULTS

155 patients underwent standard and 66 patients extended CRT. Patients undergoing extended CRT were more likely to harbor larger initial tumor size (p = 0.04), baseline nodal metastases (cN+; p < 0.001) and higher tumor location (p = 0.02). Cox-regression analysis revealed that the type of nCRT regimen was not independently associated with distinct surgery-free survival after cCR or distant-metastases-free survival (p > 0.05).

CONCLUSIONS

Dose-escalation and consolidation chemotherapy are insufficient to increase long-term surgery-free survival among cT3 rectal cancer patients and provides no advantage in distant metastases-free survival.