Prostate cancer is the most common non-skin cancer among men. The disease can be screened but many patients still die from it each year. For people who have prostate cancer or know someone who does, understanding the condition can ease concerns about it.
Screening and Diagnosis
Although some men with prostate cancer may occasionally report an initial symptom, such as difficulty with urinating, the disease is usually found by screening. A digital rectal examination (DRE) allows a physician to detect any nodules, asymmetry, or other suspicious findings. In addition, the patient has a blood test for prostate-specific antigen (PSA) to see if it is elevated.
Although the PSA is fairly specific to the prostate gland, an elevated PSA does not equal prostate cancer. It simply means that something is going on with the prostate. It could be prostate cancer, but it could also be benign prostatic hypertrophy (BPH), which involves a diffusely enlarged prostate without cancer, or prostatitis, which may result from infection of the prostate. In fact, a patient may be put on a trial of antibiotics if prostatitis is suspected; if the PSA drops after antibiotics, the cause is likely prostatitis.
Nevertheless, a suspicious DRE and/or elevated PSA will prompt a physician, specifically a urologist, to perform a biopsy of the prostate. Using transrectal ultrasound (TRUS) as guidance, the urologist takes needle biopsies of the prostate through the rectal wall, collecting several samples at different areas of the prostate in a systematic manner.
Grading and Staging
If a pathologist microscopically reviewing the biopsy samples finds cancer, then he or she determines the grade, the degree of growth and differentiation of the cancer cells. For prostate cancer, this is measured by the Gleason score. Prostate cancer cells are graded from 1 to 5, with 1 representing slow growth and appearance similar to specialized prostate cells (well differentiated) and 5 representing rapid growth and appearance barely resembling prostate cells (poorly differentiated). The grades of the two most common cell grades seen under the microscope are added to form the Gleason score (e.g., 4+3).
Staging classifies how far the cancer has spread from its origin. It can be localized to the gland, spread to the lymph nodes, or metastasize to the rest of the body. Imaging studies like a CT scan and nuclear bone scan can provide additional information. Tumors are commonly staged using the TNM classification to designate where in the prostate the tumor is (T), whether lymph nodes are involved (N), and whether the cancer has metastasized (M).
Treatment
Depending on the grade and stage of prostate cancer, treatment may include observation (a.k.a. watchful waiting), surgery (prostatectomy), external beam radiation therapy, implantation of radioactive material (brachytherapy), and lowering testosterone levels (androgen ablation) with medication or surgical removal of the testes (orchiectomy). Patients should discuss with their doctor about which treatments are best for their individual case.
Other treatments remain mostly investigational, including proton beam therapy and high-intensity focused ultrasound (HIFU). They will become more available if additional studies demonstrate safety and efficacy that is comparable to standard treatment.
References
- eMedicine - Prostate Cancer: Biology, Diagnosis, Pathology, Staging, and Natural History
- eMedicine - Prostate Cancer: Management of Localized Disease
- eMedicine - Prostate Cancer: Metastatic and Advanced Disease
