1982 Volume 73 Issue 10 Pages 1269-1276
Incidental carcinoma of the prostate (occult, latent or unsuspected carcinoma, stage A or I carcinoma and TO cancer) is defined as a cancer not clinically diagnosed but discovered by pathological examination of tissue specimens after various prostatic surgeries. Treatment of incidental carcinoma has long been the subject of controversy. Recommended treatment has varied from an aggressive approach of radical prostatectomy, of definite irradiation, more conservative antiandrogen therapy, to the most conservative approach of simple observation.
In the present study, the biological potential of each incidental carcinoma was assessed on the basis of pathological findings, such as the size of cancer lesions, cell differentiation and the condition of the surgical cut end in the surgical specimens. The cancers were then classified as follows considering the heterogeneity of the tumor natures and the treatment was assigned accordingly.
Group 1) Focal (A1) and well differentiated cancers with negative surgical cut end: No treatment.
Group 2) Multifocal or diffuse (A2) and poorly differentiated cancers irrespective of the condition of surgical cut end: Immediate initiation of an antiandrogen treatment.
Group 3) Any other types of tumors including a focal (A1) well differentiated but positive cut end tumor, a focal (A1) but poorly differentiated tumor as well as a multifocal or diffuse (A2) but well differentiated tumor: No treatment but careful follow-up.
Of 19 patients with incidental carcinoma, 10 received no treatment and 9 received antiandrogen treatment. The average follow-up period was 56 months in the former and 43 months in the latter group. The 5 year and 10 year actuarial survival rates were 62.2% and 29.9% in all 19 incidental cancers and were 58.0% and 32.5% in clinically diagnosed 64 cancers (stage B, C, D) treated during the corresponding time periods, respectively. Prognosis of the incidental carcinoma was better in well differentiated tumors (n=11) with the 5 year survival of 81.8% than in poorly differentiated ones (n=8) of 41.7%. The condition of the surgical cut end did not affect the survival significantly, since the 5 year survival rate was 58.2% in positive tumors (n=12) and 66.7% in negative ones (n=7). The 5 year survival rate of no treatment group (n=10) was 100%, while that of antiandrogen treatment group (n=9) was 38.4%, which was worse than that of the clinically diagnosed cancers (58.0%, n=64).
The results clearly indicate the reliability of our therapeutic guideline for the incidental carcinoma of the prostate. We can conclude that at least half of incidental cancer, namely, A1 and well differentiated tumors, do not require further treatment. Antiandrogen treatment, however, could not yield satisfactory therapeutic results in diffuse (A2) and poorly differentiated cancers. Therefore, more aggressive therapy such as definite radiotherapy or radical surgery should be performed in the group 2 fraction (A2 poorly differentiated tumor) of incidental carcinoma.
