Happy Father's Day - Prostate Cancer
Prostate cancer is the second most frequently diagnosed cancer in men, with 903,500 new cases estimated to have occured in 2008. Nearly three-quarters of these cases were diagnosed in economically developed countries. Incidence rates of prostate cancer vary by more than 70-fold worldwide. The highest rates are recorded primarily in the developed countries of Europe, North America, and Oceania, largely because prostate specific antigen (PSA) testing is widely used and detects clinically important tumors, as well as other slow-growing cancers that might otherwise have escaped diagnosis. The lowest rates are in many parts of Asia.
With an estimated 258,400 deaths in 2008, prostate cancer was the sixth leading cause of cancer death in men worldwide. Men of African descent in the Caribbean region have the highest prostate cancer mortality in the world, with age standardized rates more than four times higher than those in the US and more than 15 times higher than those in the Middle East and Eastern Asia. The reason for the high prostate cancer risk among some populations of African descent is still poorly understood, though it may in part reflect differences in genetic susceptibility.
Temporal trends in prostate cancer death rates are easier to interpret than trends in incidence rates because they are less affected by changes in PSA screening rates. Incidence trends follow a consistent pattern in countries with higher uptake of PSA, such as Australia, Canada, and the United States, with a rapid rise in incidence in prostate cancer in the early 1990s soon after the introduction of PSA testing followed by a sharp decline. In other high-income countries with low prevalence of PSA testing, such as Japan and the United Kingdom, the dramatic peak in incidence is not observed, though rates continue to increase slightly. Death rates for prostate cancer have been decreasing in many developed countries, including Australia,Canada, Finland, France, Israel, Italy, The Netherlands, Norway, Portugal, Sweden, the United Kingdom, and the United States. In contrast, mortality rates are rising in some Asian and Eastern European countries, such as Japan, Singapore, and Poland. While the decrease in prostate cancer death rates in Western European and North American countries has been attributed mainly to improved treatment, the increase in Asian and Eastern European countries has been thought to reflect westernization, including increased consumption of animal fat, obesity, and physical inactivity.
Early prostate cancer usually has no symptoms. With more advanced disease, individuals may experience weak or interrupted urine flow; inability to urinate or difficulty starting or stopping the urine flow; the need to urinate frequently, especially at night; blood in the urine; or pain or burning with urination. Continual pain in the lower back, pelvis, or upper thighs may be an indication of spread of the disease to the bones. Many of these symptoms, however, are similar to those caused by benign conditions.
The only well-established risk factors for prostate cancer are older age, race (black), and family history of the disease. About 62% of all prostate cancer cases in the United States are diagnosed in men 65 and older. Recent genetic studies suggest that strong familial predisposition may be responsible for 5% to 10% of prostate cancers. Some studies suggest that a diet high in processed meat may also be a risk factor. There is some evidence that the risk of dying from prostate cancer is increased by obesity.
Although modifiable risk factors for prostate cancer are not understood well enough to make definitive recommendations for preventive measures, factors that may reduce risk include maintaining a healthy body weight, getting regular physical activity, and consuming a diet low in animal fat and high in fruits and vegetables. Evidence about the value of testing for early prostate cancer detection is insufficient to recommend for or against screening with PSA for men at average risk.70 However, PSA is widely used in North America, Australia, and parts of Europe. The American Cancer Society recommends that men who are at average risk of prostate cancer, do not have any major medical problems, and have a life expectancy of at least 10 years receive information about the benefits and limitations of testing for early prostate cancer detection beginning at age 50 and have an opportunity to make an informed decision about testing. Results of two large clinical trials designed to determine the efficacy of PSA testing were recently published. A European study found a lower risk of death from prostate cancer among men receiving PSA screening, while a US study did not.74 Further analyses of these studies are under way.
Treatment options vary depending on age, stage, and grade of the cancer, as well as other medical conditions. Surgery (open, laparoscopic, or robotic assisted), external beam radiation, or radioactive seed implants (brachytherapy) may be used to treat early stage disease. Hormonal therapy, chemotherapy, and radiation (or combinations of these treatments) are used for metastatic disease and as a supplemental or additional therapy for early stage disease. Hormone treatment may control prostate cancer for long periods by shrinking the size or limiting the growth of the cancer, thus relieving pain and other symptoms. Careful observation (“watchful waiting” or “active surveillance”) rather than immediate treatment may be appropriate for some men with less aggressive tumors, especially older men with limited life expectancy and/or other health considerations.
Over the past 25 years, a dramatic improvement in survival has been observed, partly attributable to earlier diagnosis of asymptomatic cancers (some of which would never have become clinically evident) and improvements in treatment. The five-year relative survival rate for patients diagnosed with prostate cancer in the United States approaches 100% and in Europe ranges from 48% (Denmark) to 87% (Austria). In sub-Saharan African and Southeast Asia, the five-year survival rate is less than 40% in most countries.