Rectal cancer adjuvant chemotherapy: when is more useful?

THE AIM of the study was to evaluate time-to-progression (TTP) of rectal cancer in a group of patients receiving adjuvant chemotherapy (CHT) after combined neoadjuvant treatment. A secondary end-point was to identify the possible influence of clinical TNM (cTNM) or pathological TNM (pTNM) on TTP and overall survival (OS).

From January 2000 to December 2005, 101 consecutive rectal cancer patients who had been neoadjuvantly treated and had underne adjuvant CHT were retrospectively examined. The variables considered were age, gender and clinical and pathological effect of CHT administration.

The mean age was 59 years (29-78 years) and the male:female ratio, 61:40. Forty-two patients had a lower (< or =5 cm from the anal verge), 54 a middle (from 6 to 10 cm) and 5 a higher (=10 cm) rectal lesion. All the patients had received the full course of neoadjuvant radiotherapy (RT) while 26.7% patients had received a reduced number of neoadjuvant CHT cycles. All the patients had undergone surgery and had received adjuvant chemotherapy which was completed in only 77.2% of the cases. Tumour down-staging and complete remissions were reported in 75.2% and 14.8% of cases, respectively. TTP and OS at 3 years were 81.2% and 91.1%, respectively. Out of locally recurrent patients, 77.8% were N+ (p=0.0026) at the pathological evaluation.

In our series, neither administration of oxaliplatin-based adjuvant chemotherapy (p=0.44) nor age > or =70 years (p=0.51), clinical stage III (p=0.67), tumour down-staging (p=0.44) and achievement of pCR (p=0.66) appeared to have a significant impact on TTP; only pN+ (patients "not responders" to a neoadjuvant CHT-RT) influenced local relapse requiring more accurate postoperative treatment and confirming the literature data about the utility of adjuvant therapy in stage III disease.