New grade-related prognostic variable for rectal cancer.

Abstract

The effect of microacinar growth patterns on survival after radical surgery for rectal cancer was assessed in 138 consecutive patients. All had Dukes and Jass staging and a median follow-up of 95 (range 11-180) months. Tumour acini were classified according to size (microacinar, 28; macroacinar, 110). Patients with microacinar tumours had a significantly reduced 5-year survival rate compared with those with macroacinar lesions (43 and 68 per cent respectively, P = 0.004). When examined in the presence of other histological factors, acinar size had independent prognostic value (relative risk 2.37, P = 0.006). This was true even when the Dukes and Jass classifications were included in the model (relative risk 2.08, P = 0.02 and 1.95, P = 0.03 respectively). Histological classification of rectal tumours into microacinar and macroacinar types adds prognostic value to the Dukes and Jass classifications and may be a more objective criterion than conventional histological grading.