Partial sampling of radical prostatectomy specimens: detection of positive margins and extraprostatic extension

Currently there is no global agreement as to how extensively a radical prostatectomy specimen should be sectioned and histologically examined. We analyzed the ability of different methods of partial sampling in detecting positive margin (PM) and extraprostatic extension (EPE)-2 pathologic features of prostate cancer that are most easily missed by partial sampling of the prostate. Radical prostatectomy specimens from 617 patients treated with open radical prostatectomy between 1992 and 2011 were analyzed. Examination of the entirely submitted prostate detected only PM in 370 (60%), only EPE in 100 (16%), and both in 147 (24%) specimens. We determined whether these pathologic features would have been diagnosed had the examination of the specimen been limited only to alternate sections (method 1), alternate sections representing the posterior aspect of the gland in addition to one of the mid-anterior aspects (method 2), and every section representing the posterior aspect of the gland in addition to one of the mid-anterior aspects, supplemented by the remaining ipsilateral anterior sections if a sizeable tumor is seen (method 3). Methods 1 and 2 missed 13% and 21% of PMs and 28% and 47% of EPEs, respectively. Method 3 demonstrated better results missing only 5% of PMs and 7% of EPEs. Partial sampling techniques missed slightly more PMs and EPEs in patients with low-risk to intermediate-risk prostate cancer, although even in high-risk cases none of the methods detected all of the studied aggressive pathologic features.