The only definitive diagnosis of prostate cancer is through biopsy. The digital rectal exam can reveal an enlarged prostate, which is not necessarily an indication of cancer. Elevated PSA can only be considered as a screening tool to suggest further work-up, e.g. biopsy.

If you are having problems emptying your bladder, the digital exam is a quick, minimally invasive test that can reveal an enlarged prostate obstructing the urethra, which is not necessarily cancerous. Non-invasive bladder ultrasound (much like the ultrasounds women get when pregnant) can show whether your bladder fully empties when you void, which can be an indication for further treatment. Treatment for prostatic hypertrophy can either be medical or surgical. Surgical treatment has the advantage of obtaining tissue that can be tested for cancer cells.

That said, prostate cancers tend to be quite slow growing, and there is evidence accumulating that hasty treatment of a diagnosed prostate cancer is not always the best option, as there can be considerable side-effects. Many men die of natural causes long before their prostate cancer becomes a significant risk to their health, so passive monitoring is often now considered to be an appropriate response to finding an enlarged prostate. Nor is an enlarged prostate the only possible explanation for voiding difficulties. If you feel this is affecting your quality of life, seek a referral to a urologist.

(writing as a retired RN who has seen my share of urology patients)