Prostate Cancer Aggressiveness Linked to Gland Size
Small glands are associated with higher rates of positive surgical margins, non-organ-confined tumors.
SHANGHAI—Two new studies provide additional evidence that prostate cancer patients who have small prostates are more likely to have positive surgical margins and other evidence of higher-risk tumors.
Researchers reviewed the records of 1,296 patients who underwent robotic-assisted laparoscopic prostatectomy (RALP) between January 2005 and August 2008 at New York Presbyterian Hospital. Smaller prostates were significantly associated with a higher risk of positive surgical margins. The positive surgical margin rate was 10.9% for men with prostates weighing 50 grams or less versus 7.2% for prostates larger than 50 grams, a significant difference between groups. Positive margins also were significantly associated with higher preoperative PSA levels and Gleason sum on final histology.
Gerald Y. Tan, MD, of the Weill Medical College of Cornell University in New York City, and his colleagues noted that their findings mirror those of a study led by Stephen J. Freedland, MD, of Johns Hopkins School of Medicine in Baltimore (J Clin Oncol. 2005;23:7546-7554). The study showed that men with smaller prostates had more high-grade cancers and more advanced disease and were at greater risk of progression after radical prostatectomy.
Dr. Tan said he and his team agree with the hypothesis of Dr. Freedland's group that for a given age, a small prostate with the same PSA as a larger gland is likely associated with lower androgenicity and lower overall intraprostatic growth factor concentrations, which may promote the development of aggressive cancers.
“Accurate preoperative assessment of prostate weight may help surgeons better predict who is likely to have more aggressive disease on final pathology and help them adjust their operative strategies for cancer clearance accordingly,” said Dr. Tan, who worked with the research team of Ashutosh Tewari, MD, Ronald P. Lynch Chair of Urologic Oncology and Director of the Lefrak Institute of Robotic Surgery at Weill.
In addition, a team of German and Turkish researchers analyzed records of 71 men with small prostates (25 cc or less) and 76 men with large prostates (75 cc or more) who underwent laparoscopic radical prostatectomy. The positive surgical margin rate was 21% in the small-prostate group compared with 7.9% in the large-prostate group. Moreover, a higher proportion of men with small prostates presented with non-organ-confined tumors (46.5% vs. 28.9%), a Gleason score of 7 and higher (59% vs. 33%), and biochemical recurrence (23.9% vs. 5.2%). All of the between-groups differences were significant.
Both studies were presented here at the 2008 World Congress of Endourology.