Survival outcomes following adjuvant fluoropyrimidine-containing chemotherapy for resected early stage rectal adenocarcinoma (#97)
Recent data have created uncertainty regarding the benefit of the current standard of care adjuvant fluoropyrimidine-containing chemotherapy following preoperative chemoradiotherapy and surgical resection for locally advanced rectal cancer. In particular, patients with a pathologic complete response may derive no benefit from adjuvant chemotherapy.
This is a retrospective analysis of patients with early stage rectal adenocarcinoma, diagnosed between 1 January 2003 and 30 June 2013 at three Melbourne health services (Eastern Health, Royal Melbourne Hospital and Western Health). Patients were identified from a search of the ACCORD (Australian Comprehensive Cancer Outcomes and Research Database) database, where a defined data set is prospectively collected on consecutive patients. Patient demographics, pre-treatment staging, post-operative treatment, recurrence and survival were analysed.
A total of 580 patients with localised rectal cancer were identified, of whom 451 had received neoadjuvant long course chemoradiation followed by resection of the primary tumour. 369 patients (82%) subsequently received adjuvant 5-fluorouracil. At a median follow-up of 45.9 months, 63 (19%) patients in the adjuvant chemotherapy group and 21 (29%) in the surveillance only group had relapsed. Median relapse-free survival (RFS) has not been reached in either group; 3-year RFS was 81% in the adjuvant chemotherapy group compared to 71% in the surveillance only group (p=0.034). Five-year overall survival was 83% in the adjuvant chemotherapy group compared to 71% in the surveillance only group (p=0.038). The impact of age, surgical complications, treatment-related toxicity and pathological complete response post neoadjuvant therapy on the uptake of post-operative chemotherapy and on survival are being evaluated.
A high proportion of patients in routine practice receive adjuvant chemotherapy following neoadjuvant treatment and surgery for early stage rectal cancer. Adjuvant chemotherapy was associated with a significant improvement in 3-year relapse-free and 5-year overall survival.