ESTIMATION OF TUMOR VOLUME IN RADICAL PROSTATECTOMY SPECIMENS IN ROUTINE CLINICAL-PRACTICE

Tumor volume may be an independent prognostic factor in prostatic aden ocarcinoma but is too difficult, expensive, and time consuming to meas ure in routine clinical practice. We sought to evaluate several simple estimates of tumor volume in radical prostatectomy specimens. Specime ns from 86 radical prostatectomies were completely sectioned, and the true tumor was volume calculated using a computer-assisted image analy sis technique. True tumor volume was then compared with the results of several estimation techniques. True tumor volume ranged from 0.004 to 9.74 cc (mean, 1.59 cc). The Pearson correlation coefficient of the l ength of the maximum dimension of tumor as measured from the slide wit h true tumor volume had an r(2) of 0.688. However, 15 (75%) of 20 tumo rs less than 0.5 cc had a single maximum diameter of less than 10 mm, and only 3 (4%) of 66 tumors with volumes greater than 0.5 cc had a ma ximum diameter of less than 10 mm. Fifteen (68%) of 22 tumors with tru e tumor volumes greater than 2 cc had a maximum dimension greater than 20 mm, and only 2 (3%) of 64 tumors with volumes less than 2 cc had a maximum dimension greater than 20 mm. Increasing correlation with tru e tumor volume could be obtained from the largest single tumor area (r (2) = 0.749), the sum of the largest dimensions of two separate tumor foci (r(2) = 0.759), and the sum of the two largest areas (r(2) = 0.85 9). For tumors with true volumes less than 0.5 cc, only 1 (5%) of 20 c ases had a sum of the two largest areas greater than 65 mm(2), and no tumor larger than 0.5 cc had a sum of less than 65 mm(2). For tumors l arger than 2 cc, 19 (86%) of 22 tumors had a sum of the two largest ar eas greater than 250 mm(2), and only 1 (2%) of 64 cases with a true tu mor volume less than 2 cc had an area greater than 250 mm(2). We concl ude that tumors in radical prostatectomy specimens can be st atified b y size based on simple measurements obtainable during routine patholog y practice.