Q: Is prostate cancer really the most common form of cancer in men? Where is the prostate, what is its function? What causes prostate cancer, how can it be prevented, how is it treated?

Bernard L., Coloocan City

A: Yes, among men, prostate cancer is currently the most common form of cancer and the second most common cause of cancer death worldwide. In the Philippines, however, it is among the top five but is not the most prevalent form of malignancy in men. This is either because Filipinos have a lower risk for the disease or the disease is being under-diagnosed in the country.

Prostate cancer is a very slow growing malignancy. Often, it persists for years without producing any symptom. In fact, prior to the introduction of PSA testing, most men with prostate cancer outlived their disease and died from other causes without ever knowing they had cancer. Thus, the steady increase in occurrence of prostate cancer in the last few decades is probably due to the increasing utilization of the two screening procedures for the disease (i.e., PSA testing and digital rectal exam) rather than to an actual increase in incidence of the malignancy.

PSA testing is a blood test that measures prostate specific antigen (PSA) while the digital rectal exam is a procedure conducted by a physician that involves feeling for abnormalities in the prostate through the rectal wall by inserting a rubber-gloved finger in the rectum.

The prostate is a small gland (4cm x 3 cm x 2 cm) gland whose secretion forms part of semen. It lies under the urinary bladder and it surrounds the initial part of the urethra, the tube that empties urine from the bladder.

The exact cause of prostate cancer is unknown, but a few risk factors for the disease have already been identified: advancing age (more than 70 percent of prostate cancers occur in men above 65 years old), a family history of the disease, race — it is more common among blacks than among whites and is evidently relatively uncommon among Asians, and certain changes in some genes. Since the cause is unknown and the risks factors poorly understood, no effective preventive measures for the disease exists.

Typically, prostate cancer does not cause symptoms until it has grown big or has spread to other organs. When symptoms occur, they are often non-specific. They include difficult, frequent and painful urination, weak or interrupted flow of urine, bloody urine, and painful ejaculation. In any case, definitive diagnosis of prostate cancer hinges on a positive transrectal biopsy, which entails obtaining prostate tissue then examining the same for cancer cells under the microscope.   

The management options for prostate cancer include surgery, radiotherapy, chemotherapy, hormone therapy and watchful waiting. The option/s to employ depends on the stage of the cancer and state of health of the patient.

The treatment modalities for prostate cancer, particularly surgery and radiation, can cause long-term adverse effects such as urinary incontinence and impotence. Likewise, they do not guarantee cure or longer life expectancy. Thus, treating a very slow growing prostate cancer may be more damaging than leaving it untreated. That is why watchful waiting is a good option for early stage prostate cancer that seems to be slowly growing especially in patients who are old or with other health problems. Watchful waiting involves regular consultation (every three to six months) with a physician who might occasionally order a PSA and other tests. Treatment is indicated only if:  there is evidence of cancer growth; the PSA level increase; or, symptoms appear.

At present, experts disagree on the value of digital rectal exam and PSA testing in screening for prostatic cancer. In fact, the American Cancer Society does not support routine testing for prostate cancer at this time. The PSA test, for one, is not diagnostic of prostate cancer; many other conditions give rise to elevated PSA level. Sometimes, the PSA level does not go up even if there is cancer. There are, however, ongoing studies designed to resolve this issue.

(E-mail inquiries on health matters to: medical_notes@yahoo.com or wellbeing@mb.com.ph.)