This study compares the outcomes of patients with pathological (p) T3N0 rectal cancer treated with surgery alone (S), surgery and radiation (SR) or surgery, radiation and chemotherapy (SRC), in a population based setting.

Three hundred and seven patients with operable, macroscopically resected pT3N0 rectal cancer referred to the BC Cancer Agency between 2000 and 2004 were segregated by treatment type: S (n=65), SR (n=97) and SRC (n=145). Patient characteristics, 5-year locoregional recurrence (LRR) and disease-specific survival (DSS) were compared between treatment cohorts.

Median age differed significantly between S, SR and SRC patient cohorts: 76, 72 and 64 years respectively. Five-year LRR differed by treatment group, with 29% for S, 6.3% for SR and 3.84% for SRC patients. DSS was superior in SRC compared to S patients (hazard ratio=0.31 [0.17, 0.60]). Co-morbidities and patient preference were most common reasons for omission of radiation.

Unselected patients with pT3N0 rectal cancer not treated with peri-operative radiation experience a high rate of LRR and reduced DSS in comparison to patients treated with bimodality and trimodality therapies. Advanced age is significantly associated with omission of therapy in patients with early stage rectal cancer.