Prostate Cancer, To Treat or Not to Treat
When it comes time for a man to decide if he should treat a diagnosed case of prostate cancer, the evidence is growing that treatment may not make much difference when it comes to survival. What may matter, however, are the potentially severe side effects men may experience when undergoing treatment they may not need.
The latest study to note that use of the prostate-specific antigen (PSA) test may be prompting men to get treatment that may not be effective or even necessary was published in the current issue of the Journal of the National Cancer Institute. The results support those of two previous studies from 2008. It seems that although high levels of PSA revealed on the blood screen can indicate the presence of prostate cancer, the test is not effective in predicting if treatment will be helpful.
Generally, prostate cancer is a slowly progressing cancer. When prostate cancer does advance rapidly, it “may grow so rapidly that screening doesn’t really help,” said H. Gilbert Welch of the Dartmouth Institute for Health Policy and Clinical Practice during an interview with National Public Radio. By the time screening detects these cancers, they have already spread. Other prostate cancers grow so slowly that men who have the disease are likely to die of something other than the cancer.
Indeed, the survival rate for prostate cancer is good. According to the American Cancer Society, the five-year survival rate is nearly 100 percent, and the ten-year rate is 91 percent. At fifteen years the rate is 76 percent. The results of the two studies published last year showed no difference (one study) and only a slight advantage (one study) in the number of prostate cancer deaths among men who were screened regularly as compared with men who were not screened.
According to a study published in the August 2009 issue of the Journal of Clinical Oncology, the likelihood of dying from prostate cancer is low, especially for cancers that are low grade and slow growing. The authors, who followed more than 12,000 men (all with prostate cancer) for 15 years reported that a watch and wait approach may be more appropriate and less likely to leave men experiencing impotence and other side effects.
The available treatments for prostate cancer, including surgery, radiation, targeted therapy, and chemotherapy, can cause severe side effects. Approximately one-third of treated men can expect to experience impotence, incontinence, or both. Other side effects, depending on the therapy, can include nausea, vomiting, rash, pain, loss of sexual desire, diarrhea, and fatigue.
Therefore, men who are approaching 50 have a decision to make along with their doctors: should they undergo the PSA test or not? The Food and Drug Administration recommends that all men age 50 and older get screened yearly. Not all doctors agree with this schedule. Some argue that if men do not plan to seek treatment if they test positive for prostate cancer, there is no need to undergo screening at all.
The American Cancer Society and the US Preventive Services Task Force recommend that men who are contemplating a PSA test should be presented with all the evidence about PSA screening and about prostate cancer, its treatment, and prognosis, and let them make their own educated choice whether to undergo screening and/or seek treatment.
American Cancer Society
National Public Radio interview Sept. 4, 2009
Shappley WV et al. Journal of Clinical Oncology 2009 Aug 31