Morphological analysis and classification of latent prostate cancer using a 3-dimensional computer algorithm: analysis of tumor volume, grade, tumor doubling time and life expectancy

Abstract

Purpose: We estimate the potential clinical significance of prostate cancers found at autopsy provided the individual had lived to the projected lifespan based on life expectancy tables.

Materials and methods: We used 3-dimensional computer models of 59 autopsy prostates that contained clinically undetected carcinoma to determine tumor volumes. Using doubling times of 2, 3, 4 and 6 years, carcinoma volumes at autopsy were extrapolated through patient projected lifespans. The carcinomas were then classified as clinically insignificant or significant according to Mayo Clinic criteria.

Results: In 13 patients less than 60 years old, using doubling times of 2, 3, 4 and 6 years, clinically significant tumors were identified in 13 (100%), 10 (77%), 7 (54%) and 7 (54%), respectively. In 46 patients 60 years old or greater significant tumors were identified in 32 (70%), 22 (48%), 21 (46%) and 18 (39%), respectively. A statistical difference (p <0.0001) was found between the mean tumor volume (0.20 +/- 0.10 cc) of 43 organ confined carcinomas and the mean tumor volume (3.26 +/- 3.58 cc) of 16 extracapsular tumors. No capsule perforation was found in tumors with Gleason sums of 4 or less. However, capsule perforation was present in 8 of 31 tumors (25.8%) with Gleason sums of 5 or 6, and 8 of 11 tumors (72.7%) with Gleason scores of 7 or 8.

Conclusions: Prostatic carcinomas that remain clinically insignificant throughout life are likely to have doubling times greater than 4 years. The subset of carcinomas that emerge as clinically significant are likely to have doubling times less than 3 years. Therefore, an accurate method to measure doubling time at diagnosis could, provide an objective indicator to guide clinical management.