Robot-assisted radical prostatectomy (RARP) for prostate cancer is technically challenging for men with large prostates, but it can be performed safely and with good surgical, oncologic, and functional outcomes, researchers have reported.

In a retrospective study, Apostolos P. Labanaris, MD, PhD, and colleagues at Prostate Center Northwest, St. Antonium Hospital, Gronau, Germany, compared 185 RARP patients with a pathologic prostate specimen weighing 100 grams or more with a matched control group of RARP patients with a pathologic prostate specimen weighing 50 grams or less and who had clinicopathologic characteristics similar to those of the large-prostate group.

Compared with the control group, the large-prostate group had significantly greater median estimated blood loss (192 vs. 152 mL) and operative time (164 vs. 144 minutes), the investigators reported in Urologia Internationalis (2013;90:24-30). Significantly more patients in the large-prostate group than the control group underwent bladder neck reconstruction (28% vs. 5.9%) and experienced intraoperative complications (4.8% vs. 1.6%).

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The patients with large prostates, however, had significantly lower rates of aggressive tumors and positive surgical margins (PSMs). Ninety patients (48.7%) in the large-prostate group had a Gleason score less than 7 compared with 76 patients (41.1%) in the control group. A Gleason score of 7 was found in 63 patients (34.1%) in the large-prostate group compared with 80 (43.3%) of the control group. The two groups had similar proportions of patients with a Gleason score above 7 (15.1% and 15.6%). Nine patients (4.8%) of the men with large prostates had PSMs compared with 20 (10.8%) control patients. Furthermore, 8% of patients with large prostates experienced biochemical recurrence (BCR) after a median follow-up of 23.6 months, whereas 13.1% of control patients experienced BCR after a median follow-up of 21.6 months. The researchers defined BCR as a 0.2 ng/mL PSA rise above nadir or a PSA level that never reached nadir.

The two treatment arms had similar continence rates, but the men with the large prostates had significantly lower potency rates.

Dr. Labanaris’ group concluded that RARP in patients with a pathologic prostate specimen weight of 100 grams or more is a technically challenging procedure due to reduced mobility in the pelvis, impaired visualization, limited working space, and manipulation and rotation of the gland, but “in experienced hands it can be considered a safe procedure with excellent surgical, oncological and functional outcomes.

The researchers noted that their findings are limited because they are based on a series from a single institution with a large case volume and may not reflect outcomes at centers with smaller volumes and less experience. In addition, the median postoperative follow-up was short so the long-term functional and oncologic results cannot be evaluated.