title: Prognostic significance of the pattern of tumor regression following definitive radiotherapy for carcinoma of the prostate.
abstract: Postirradiation evaluation of 262 patients, treated with curative intent from 1967 to 1981, included systematic recording of the degree of tumor regression (expressed as percentage of the tumor size on presentation) at 90 days after completion of radiotherapy, and the time to complete regression of the palpable tumor. These two parameters were correlated with the tumor extent (stage) and histological grade. Although smaller (lower stage) tumors appeared to regress somewhat faster in the early postirradiation period, this trend was not statistically significant. Similarly, the time to complete regression did not differ significantly among extent (stage) and histological grade categories. The overall complete response rate at 6, 12, and 24 months was approximately 55, 80, and 90%, respectively. In 14 patients, palpable tumor never regressed completely. All of these patients suffered a relapse. Late resolution (second year or later) was not associated with a significant increase in the incidence of locoregional recurrence. The degree of tumor regression at 90 days after completion of treatment correlated well with the locoregional control rate. Regression of 50% or more at 90 days was associated with a significantly lower probability of locoregional failure (25% versus 45%). Assessment of the degrees of tumor regression early in the postirradiation course (at 90 days) is a useful prognostic indicator.
mesh_terms: D002277:Carcinoma / Q000473:pathology / Q000532:radiotherapy*; D006801:Humans; D008297:Male; D009362:Neoplasm Metastasis; D009364:Neoplasm Recurrence, Local; D009367:Neoplasm Staging; D011379:Prognosis; D011471:Prostatic Neoplasms / Q000473:pathology / Q000532:radiotherapy*; D013997:Time Factors