Prostate cancer is the most common cancer among men in the U.S. and the second most common cause of cancer-related deaths. And African-American men are more likely to get prostate cancer and twice as likely to die from the disease than men of other races.
The prostate is part of the male reproductive system that makes semen. The walnut-sized gland is beneath the bladder and surrounds the upper part of the urethra, the tube that carries urine from the bladder.
The U.S. Food and Drug Administration regulates certain tests and treatments for prostate cancer to ensure their safety and effectiveness.
Signs and Symptoms of Prostate Cancer
Prostate cancer is frequently a very slow-growing disease, often causing no symptoms until it is in an advanced stage. At that point, symptoms may include difficulty starting urination, weak or interrupted flow of urine, and frequent urination, especially at night. Other symptoms of advanced prostate cancer may include back or other bone pain, weakness, and unintended weight loss.
But these symptoms can have many other causes than prostate cancer, such as a harmless (benign) enlarged prostate. If you have any concerns about any of these symptoms, contact your health care professional.
Most patients with prostate cancer die of other causes, and many never know they have the disease. But once prostate cancer begins to grow quickly or spreads outside the prostate, it is dangerous.
Tests to Detect Prostate Cancer
A blood test that measures prostate-specific antigen (PSA) can be used to help with the detection of prostate cancer, although it is not recommended for screening in all cases. PSA is a protein produced by cells of the prostate gland.
Other factors that may help to put the PSA into context to better understand the risk of prostate cancer include age, race, family history, prostate size, urinary tract infection or irritation, medications and rate of PSA rise.
Because of the widespread use of PSA testing in the U.S., prostate cancer is often detected early. In some cases, the prostate cancer found can be very slow-growing, and this can lead to overtreatment.
“In most of these cases, the prostate cancer may not require treatment, and the use of PSA testing to screen for prostate cancer is controversial,” says Daniel Suzman, M.D., a medical oncologist at the FDA.
The U.S. Preventive Services Task Force – an independent, volunteer panel of national experts in prevention and evidence-based medicine – recommends against PSA-based screening for prostate cancer in men age 70 and older because of:
- The lack of data that screening increases survival rates.
- The risk of overtreatment, leading to side effects in men who otherwise would never have experienced any symptoms.
For men ages 55 to 69, the task force recommends an individualized discussion of the risk and benefits of screening.
Imaging of the prostate, such as magnetic resonance imaging (MRI), may help with detecting prostate cancer. If the risk of prostate cancer is high, a health care professional performs a biopsy to remove a sample of prostate tissue for examination to determine if cancer is present and, if so, how aggressive the cancer appears.
The appearance of aggressiveness under the microscope is described by a Gleason score, which is assigned by the pathologist (a doctor who examines bodies and body tissues). Depending on the overall risk for prostate cancer that has spread outside the prostate, additional imaging may be needed to recommend a treatment plan.
How Prostate Cancer Is Treated
Localized Prostate Cancer: Radiation and/or surgery are the preferred treatments for localized prostate cancer that is at risk for spread. Radiation may be given after surgery to certain patients if they are at high risk for any prostate cancer remaining. Side effects from treatment of prostate cancer with surgery or radiation therapy can include effects on urination, erectile dysfunction, and bowel problems.
Hormone Therapy: Radiation therapy is sometimes combined with hormone therapy (also called androgen deprivation therapy, or ADT). Androgens, such as testosterone, are hormones that can cause prostate cancer cells to grow. ADT stops testosterone from being produced or directly blocks it from acting on prostate cancer cells. Hormone therapy may be given to patients with prostate cancer that has recurred after radiation or surgery and is the standard of care for patients with cancer that has spread outside the prostate to other areas of the body (metastatic disease). Side effects from ADT are largely due to the loss of testosterone and can include hot flashes, weight gain, loss of bone density, erectile dysfunction, and fatigue.
Non-Metastatic Castration-Resistant Prostate Cancer: Some men who are treated with hormone therapy before they experience metastatic disease may develop a form of prostate cancer that is resistant to standard hormone therapy (known as non-metastatic castration-resistant prostate cancer). The FDA has approved three drugs for non-metastatic castration-resistant prostate cancer: apalutamide, enzalutamide and darolutamide. These drugs block the effect of testosterone and similar hormones on the prostate cancer cells. Patients who received these drugs in clinical trials went longer without developing metastatic disease than patients who received placebo; they also lived longer.
Metastatic Castration-Resistant Prostate Cancer: In 2004, the FDA approved docetaxel. This is the first approved chemotherapy drug for metastatic castration-resistant prostate cancer (i.e. resistant to hormone therapy alone) that showed a survival benefit, after years of research failed to find a treatment that would prolong the lives of metastatic prostate cancer patients.
“When prostate cancer metastasizes to another location in the body, it is in most cases incurable, and the goal of treatment is to improve a patient’s symptoms or function, or to extend the length of the patient’s life,” Suzman says.
Since the approval of docetaxel, the number of therapies for metastatic prostate cancer has continued to grow. The FDA has approved six additional therapies for metastatic castration-resistant prostate cancer, all of which have shown improvements in survival and are not directed to specific mutations in the cancer. These include hormonal therapy, chemotherapy, a cancer vaccine, and radioactive drugs.
Additionally, the FDA has approved four therapies for patients with metastatic castration-resistant tumors that require testing for specific mutations in the prostate cancer to determine if the patient may be a candidate for treatment. Some of these therapies are approved in combination with a hormonal therapy, such as abiraterone or enzalutamide.
Metastatic Castration-Sensitive Prostate Cancer: For patients with previously untreated metastatic prostate cancer, several major trials showed that adding additional therapy, including hormonal therapies (abiraterone acetate, enzalutamide or apalutamide), docetaxel, or darolutamide with docetaxel, improved their survival. According to Suzman, this approach has become a standard of care for patients with previously untreated metastatic prostate cancer.
To receive docetaxel, patients must be fit for chemotherapy. Abiraterone acetate tablets are also approved, in combination with prednisone, for patients with metastatic high-risk, castration-sensitive prostate cancer, while enzalutamide and apalutamide are each approved for all patients with metastatic castration-sensitive prostate cancer.
Emerging Research in Prostate Cancer
One promising area of prostate cancer research is related to preventing overtreatment of patients with prostate cancer that is still localized to the prostate and who have a low risk of becoming symptomatic or dying from the condition. There is increasing evidence that close surveillance and repeated biopsies may safely allow these patients to delay definitive therapy (surgery or radiation).
“There is a need to reduce the burden to patients of overtreatment if the prostate cancer is slow-growing,” Suzman says.