THE "NEW" PROSTATE CANCER INFOLINK

So now we have data from a prospective study (carried out as part of the European Prospective Investigation into Cancer and Nutrition) that was designed (in part) to explore whether there was any association between vasectomy and risk for prostate cancer.

In a recently published paper in the Journal of Clinical Oncology, Byrne et al. report data from their study of 84,753 men from Denmark, Germany, Spain, and the United Kingdom, all aged between 35 and 79 years, who provided information on vasectomy status at the time of recruitment and who were the followed prospectively to establish incidence of prostate cancer and prostate cancer-specific mortality.

The full text of the article by Byrne et al. is available on line.

The authors report that:

• Average (mean) age of men at recruitment was 53 years.
• Average (mean) age of men at diagnosis with prostate cancer was 68 years.
• Average (median) follow-up was 15.4 years (range 0 to 20 years).
• 12,712/84,753 patients (15.0 percent) had already had a vasectomy at time of study enrollment.
• Prostate cancer was diagnosed in
  • 4,377/84,753 participants (5.2 percent) in total
  • 641/12,712 participants (5.0 percent) who had had a vasectomy
  • 3,736/72,041 participants (5.2 percent) who had not had a vasectomy
• There was no evidence that having a vasectomy was associated with
  • Increased risk for prostate cancer (hazard ratio [HR] = 1.05)
  • Increased risk for prostate cancer-specific mortality (HR = 0.83)
• There was some evidence of heterogeneity of risk by tumor grade (P = 0.02), since having a vasectomy was associated with
  • Increased risk for low- and intermediate-grade prostate cancer (HR = 1.14)
  • No increase in risk for high-grade prostate cancer (HR = 0.83)
• There was no evidence of hetereogeneity of risk based on
  • Stage of disease at diagnosis
  • Years since vasectomy

Data from the study also confirmed an oft-mentioned prior suspicion — that men who had had a vasectomy were also more likely to get PSA tests for risk of prostate cancer. In other words, men who had a vasectomy tended to exhibit “health-seeking behavior” to a higher degree than the men who did not have a vasectomy. This health-seeking behavior inevitably increased the possibility that such men would be diagnosed with the low- and intermediate-risk forms of prostate cancer most likely to be diagnosed based on PSA alone.

The authors conclude that their study

did not find a significant association between vasectomy and overall prostate cancer, high-grade or advanced-stage tumors, or death due to prostate cancer. The small increase in the risk of low-intermediate–grade prostate cancer in men who had had a vasectomy may be due to differences in health-monitoring behaviors.

It is unlikely that this study will actually end men’s worries that having a vasectomy might be associated with an increased risk for prostate cancer (after all, some men are looking for any excuse not to have a vasectomy). However, what this study does do is suggest that if there is any increase in risk it is certainly small, and it is most likely to be an increase in risk for low-risk forms of prostate cancer that are unlikely to lead to metastasis or prostate cancer-specific mortality anyway.

Filed under: Diagnosis, Risk | Tagged: Diagnosis, risk, vasectomy |