Purpose: Men undergoing screening for prostate cancer are recommended to undergo digital rectal examination and prostate specific antigen measurement. We previously presented data from the Prostate Cancer Prevention Trial indicating that finasteride improves the performance characteristics of prostate specific antigen for cancer detection. In the current study we report the impact of finasteride on digital rectal examination sensitivity and specificity.
Materials and methods: We examined the sensitivity and specificity of digital rectal examination in Prostate Cancer Prevention Trial subjects receiving finasteride or placebo who underwent prostate biopsy, had prostate specific antigen measurement and digital rectal examination within 1 year before biopsy and were on treatment at biopsy.
Results: Of 9,423 men in the finasteride group 4,579 and 5,112 of 9,459 in the placebo group met study evaluation requirements. Of 4,579 men in the finasteride group 695, including 264 with Gleason 7 or greater and 81 with Gleason 8 or greater, and 1,111 of 5,112 in the placebo group, including 240 with Gleason 7 or greater and 55 with Gleason 8 or greater, were diagnosed with prostate cancer. In men in the placebo and finasteride groups digital rectal examination sensitivity was greater for detecting higher grade tumors. The sensitivity of digital rectal examination was significantly greater for cancer detection in men receiving finasteride than placebo (21.3% vs 16.7%, p=0.015). Digital rectal examination sensitivity was also greater for detecting high grade (Gleason 7 or greater and 8 or greater) cancers in men receiving finasteride but this did not attain statistical significance. Digital rectal examination specificity was similar in men receiving finasteride or placebo.
Conclusions: Finasteride significantly improves prostate cancer detection with digital rectal examination.