Prostate cancer is the most common cancer among men and the second most common cause of cancer-related deaths among American men. African-American men are more likely to get prostate cancer and twice as likely to die from the disease.
The prostate is part of the male reproductive system that makes semen. The walnut-sized gland is located 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 (FDA) regulates screening tests and treatments for prostate cancer to ensure their safety and effectiveness.
Signs and Symptoms
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.
However, these symptoms can have many other causes than prostate cancer, such as a benign enlarged prostate. If you have any concerns about any of these symptoms, you should contact your health care professional. Most men with prostate cancer die of other causes, and many never know that they have the disease. But once prostate cancer begins to grow quickly or spreads outside the prostate, it is dangerous. While the disease is rare before age 50, experts believe that most elderly men have traces of it.
Screening and Tests
Risk of prostate cancer can be measured through a blood test for prostate-specific antigen (PSA). 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. Imaging of the prostate, such as magnetic resonance imaging (MRI), may provide additional information about the risk of prostate cancer. If the risk of prostate cancer is high, the physician 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. Depending on the overall risk for prostate cancer that has spread outside the prostate, additional imaging may be needed in order to recommend a treatment plan.
Because of the widespread use of PSA testing in the United States, prostate cancer is often detected early. In some cases, the prostate cancer found can be very slow growing.
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 in the FDA’s Office of Oncologic Diseases in the Center for Drug Evaluation and Research.
The U.S. Preventative Services Task Force (USPSTF), an independent, volunteer panel of national experts in prevention and evidence-based medicine, currently recommends against PSA-based screening for prostate cancer in men 70 years and older due to the lack of data that screening increases survival rates, and because of the risk of over-treatment, leading to side effects in men who otherwise would never have experienced any symptoms. For men between 55 and 69 years old, the USPSTF recommends an individualized discussion of the risk and benefits of screening.
Localized Prostate Cancer: Radiation and/or surgery are the preferred treatments for localized prostate cancer that is at risk for spread. Radiation may be administered after surgery to certain men 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 urinary incontinence, 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 men with cancer that has spread outside the prostate to other areas of the body (metastatic disease).
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, including 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 a longer period of time without developing metastatic disease than patients who received placebo and also lived longer.
- Apalutamide Side Effects: Serious side effects of apalutamide include falls/fractures, seizure, heart disease, and stroke. Other common side effects for apalutamide include fatigue, joint pain, rash, decreased appetite, fall, weight loss, high blood pressure, hot flash, diarrhea, and fracture.
- Enzalutamide Side Effects: Serious side effects of enzalutamide include seizure, posterior reversible encephalopathy syndrome (PRES), allergic reactions, heart disease, and falls/fracture. Other common side effects of enzalutamide include fatigue, back pain, hot flashes, constipation, joint pain, decreased appetite, diarrhea, and high blood pressure.
- Darolutamide Side Effects: Common side effects of darolutamide include fatigue, joint pain, rash, decreased white blood cells, and changes in liver function tests.
Metastatic Castration-Resistant Prostate Cancer: In 2004, the FDA approved docetaxel, the first chemotherapy 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, ” says Suzman.
Since the approval of docetaxel, the number of therapeutic treatments for metastatic prostate cancer has continued to grow. The FDA has approved five 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. Additionally, FDA has approved three 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.
For patients with metastatic prostate cancer that has not been previously treated, several major trials showed that adding additional therapy, including either docetaxel or other hormonal therapies including abiraterone acetate, enzalutamide, or apalutamide, improved their survival. According to Suzman, that approach has become a standard of care for men with previously untreated metastatic prostate cancer, particularly those with a high burden of disease (such as cancer that has spread to the soft tissues or to many spots in the bone). To receive docetaxel, men 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.
- Docetaxel Side Effects: Docetaxel can cause serious side effects that may lead to death such as low white blood cell counts (neutropenia), and serious allergic reactions. Common side effects include low blood cell counts, infection, nosebleeds, decrease appetite, weight gain, rash, hair loss, and nerve pain.
- Abiraterone Side Effects: Abiraterone acetate can cause elevated levels of hormones that cause fluid retention, high blood pressure, and low potassium and must be taken with a steroid, prednisone, to prevent this. Other important side effects include liver toxicity, inability of the adrenal glands to produce enough stress hormones, as well as fatigue, joint pain, nausea, hot flush, diarrhea, vomiting, upper respiratory infection, cough, and headache.
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. Careful selection of these men to ensure that they are low-risk is crucial. 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.