Introduction: Mucinous tumours of the rectum are characterised by an abundance of extracellular mucin within the tumour complex. They are known to have a poor prognosis compared to non-mucinous adenocarcinomas. The effect of adjuvant chemotherapy on the survival outcomes of patients with mucinous cancer remains unclear. This study evaluated the 5-year overall survival of patients with mucinous rectal cancer following optimal TME surgery to determine whether adjuvant chemotherapy conferred a survival benefit.
Methods: An analysis of a prospectively-maintained database was conducted of patients presenting with mucinous rectal cancer between 2000 and 2010. Patients with mucinous tumours were identified from final pathology reports of the surgical resection specimens. The primary outcome was 5-year overall survival; univariate and multivariate analysis was performed using Cox proportional hazards regression models.
Results: A total of 191 patients were included for analysis with mean age of presentation 64.6 years (36-88 ± 11). On the fully adjusted multivariate model, EMVI status (HR 1.853, 95% CI 1.081-3.175) and not being given adjuvant chemotherapy (HR 2.888, 95% CI 1.801-4.633) were significant for disease recurrence. The 5-year overall survival for patients that had undergone adjuvant chemotherapy was 66.1% compared with 35.2% (Mantel Cox log-rank test - p < 0.0001).
Conclusion: This study demonstrates that adjuvant chemotherapy is an independent factor for improvement in overall survival in patients with mucinous adenocarcinoma. Therefore, patients who have undergone TME surgery for mucinous carcinoma of the rectum should be offered adjuvant chemotherapy even in the absence of other high-risk features for poor outcomes.
Keywords: Chemotherapy; Mucin; Mucinous; Rectal cancer; TME.
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