Comparison of pathologic characteristics of T1c and non-Tic cancers detected in a population-based screening study, the European randomized study of screening for prostate cancer

Abstract

In recent years the introduction of serum prostate-specific antigen (PSA) determination as a screening tool for early detection of prostate cancer in asymptomatic men has led to a markedly increased detection of prostate cancers that are neither palpable nor visible with transrectal ultrasonography (stage Tlc). In this preliminary study we assessed pathologic features and aspects that are indicative of clinical significance in T1c tumors and tumors with palpable or visible lesions (non-Tlc tumors). Between June 1994 and December 1995, 51 consecutive radical prostatectomies were performed on screened participants in the Rotterdam section of the European Randomized Study of Screening for Prostate Cancer (ERSPC). After determination of pathologic stage and Gleason score, morphometric analysis was performed to determine tumor volume. Radical prostatectomy specimens were divided into three mutually exclusive subsets: T1c tumors, non-Tlc tumors with preoperative PSA levels below 4 ng/ml, and non-Tlc tumors with PSA levels equal to or greater than 4 ng/ml. These subsets were compared for differences in the distribution of tumor volume, pathologic stage, and Gleason score. An arbitrarily constructed categorization model was used to assess clinical significance. In all, 17 (33%) of the patients had clinical stage T1c disease. In our categorization model, 88% of the T1c tumors fit the criteria for clinically significant tumors. T1c tumors, however, were significantly smaller (P < 0.01) and were more likely to be organ-confined (P = 0.01) as compared with non-T1c tumors in patients with an elevated preoperative serum PSA level. In contrast, tumors detected at preoperative PSA levels of < 4 ng/ml had comparably the lowest pathologic stages and tumor volumes in our series. In our categorization model, 42% of these tumors fit the criteria for minimal tumor. This group of radical prostatectomies was therefore most likely to harbor clinically insignificant cancer, a finding that was consistent in two other categorization models derived from earlier reports. T1c tumors comprise a large fraction of the tumors found in population-based screening. As judged by their pathologic characteristics, T1c tumors are clinically significant tumors. The over-all low pathologic stage and Gleason score of these tumors make these patients excellent candidates for curative treatment by radical prostatectomy or radiotherapy. In contrast, some concern should be raised on the detection of tumors at low serum PSA levels by means of digital rectal examination and transrectal ultrasound alone, since a substantial proportion of these tumors could be considered clinically insignificant. Long-term follow-up, however, is necessary to substantiate this view.