NEW GRADE-RELATED PROGNOSTIC VARIABLE FOR RECTAL-CANCER

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.