Prostate cancer is a complex disease. Doctors cannot always predict how fast or slow it will grow. Nor do they agree on when to treat it, or which treatments to use. Predicting and monitoring the disease with accuracy help doctors and patients make decisions that result in the best survival rates and quality of life.
Radical prostatectomy, external-beam radiation therapy (EBRT), and interstitial implantation of radioisotopes are each employed in the treatment of stage II prostate cancer with apparently similar therapeutic effects. Radical prostatectomy and radiation therapy yield apparently similar survival rates with as many as 10 years of follow-up. For well-selected patients, radical prostatectomy associated with a 15-year survival comparable to an age-matched population without prostate cancer. Unfortunately, randomized comparative trials of these treatment methods with prolonged follow-up are lacking.
Patients with a small, palpable cancer (T2a, N0, and M0) fare better than patients in whom the disease involves both sides of the gland (T2c, N0, and M0). Patients proven free of node metastases by pelvic lymphadenectomy fare better than patients in whom this staging procedure is not performed; however, this is the result of selection of patients who have a more favorable prognosis.
Side effects of the various forms of therapy-including impotence, incontinence, and bowel injury-should be considered in determining the type of treatment to employ. (Refer to the PDQ summary on Sexuality and Reproductive Issues for more information on impotence.)
Prostate-specific antigen (PSA) changes as markers of tumor progression
Often, changes in PSA are thought to be markers of tumor progression. Even though a tumor marker or characteristic may be consistently associated with a high risk of prostate cancer progression or death, it may be a very poor predictor of very limited utility in making therapeutic decisions.
Baseline PSA and rate of PSA change were associated with subsequent metastasis or prostate cancer death in a cohort of 267 men with clinically localized prostate cancer who were managed by watchful waiting or active surveillance in the control arm of a randomized trial comparing radical prostatectomy to watchful waiting.[3,4] Nevertheless, the accuracy of classifying men into groups whose cancer remained indolent versus those whose cancer progressed was poor at all examined cut points of PSA or PSA rate of change.