Computerized interactive morphometry in the differential diagnosis of irradiated prostates

Radiation therapy is becoming a treatment of choice for many patients with prostatic carcinoma. Distinguishing radiation change in prostate glands from carcinoma may be difficult. In this study we objectively assessed, by morphometric methods, the nuclear characteristics of benign and malignant prostates with a history of radiation treatment (1251 implant with or without prior external beam radiation). This is part of our continuing efforts to achieve difficult differential diagnoses by analyzing perimeter, diameter and nuclear profile area of cells or interest and applying methods of statistical classification. Biopsies were performed 18-36 months following implant therapy. Eleven cases with residual prostate tumor constituted the malignant group. These were compared to 20 benign cases (benign glands in the 11 carcinoma cases plus 9 other cases with no residual carcinoma). Immunohistochemical staining with keratin 903 was per formed on all cases. Differences in the nuclear parameters were most evident in the average nuclear profile areas (32.5 μm2 for the malignant groups vs. 39.6 for the benign) and in the mean maximal cord length (diameter) (7.4 μm for the malignant group vs. 9.0 for the benign). Classification, however, is based on the size distribution plots of nuclear profile areas, which, in the malignant cases, had a sharper peak at lower value, while the benign cases had higher value and a broader peak with a trailing off into the larger values. This study emphasized the marked nuclear alterations that occur in irradiated prostates. These changes, which affect the benign glands to a greater degree than the residual carcinoma, most likely are a reflection of tumor radioresistance and can be used for a differential diagnosis based on statistical classification.