A New Age Peak: Advanced Prostate Cancer Increasingly Common in Men Under 40
Although prostate cancer is considered a disease of older men, some recent research suggested an increase of cases in younger men.
A new global study found that the incidence of prostate cancer in men ages 15-40 increased approximately 2% per year since 1990. Also, in the U.S., men in this age group were six times more likely than older men to have metastatic prostate cancer when they were diagnosed.
For men in the U.S., the 5-year relative survival rate for men diagnosed with prostate cancer when they were 40-80 years old was between 95% and 100%. But for men who were diagnosed when they were 15-24 years old, the 5-year relative survival rate was only 30%; the rate was 50% for men 20-29 years old and 80% for men 25-34 years old when they were diagnosed.
Further research is needed to determine the cause of these trends and how the biology of cancer in younger men differs from that in older men.
Dr. Catalona’s Response:
For the usual “garden-variety” prostate cancer, called adenocarcinoma (cancer arising from the tiny glands within the prostate organ), the rule is that it rarely is diagnosed in men under 40. The garden-variety prostate cancer tends to be diagnosed in a localized stage and behaves less aggressively in men under 65. However, in men over 65, the incidence rate, tumor stage, and disease aggressiveness increases progressively with increasing age.
This article above calls attention to the fact that advanced, aggressive prostate malignancies also occur in men under 40, and this is being observed more often in recent years.
As is the case with garden- variety prostate cancers, these tumors in young men are more common among African-American men and less common among Asian men than among white men. Also, compared to older men, most young men with garden-variety prostate cancer have localized disease at diagnosis and a lower proportion of high-grade tumors. However, the prostate cancers diagnosed in men under 45 are more likely than those diagnosed in older men to have metastatic disease.
Some caveats should be considered concerning this study. First, the authors report that the average annual percent change in incidence is greatest in men aged 30- 45. Since the incidence was a very small number, to begin with, a relatively small increase in numbers would be magnified as a disproportionately greater increase in the percent change (i.e., small changes in very small numbers translate into large changes in percentages).
Secondly, screening for localized prostate cancer is infrequent in men aged 30-40 so slowly-growing tumors may go undetected for many years. However, advanced-stage tumors are less likely to go undiagnosed for long.
Thirdly, the authors measure patient survival as the 5-year relative survival, which is the survival of a man diagnosed with cancer compared to the survival of a man not diagnosed with cancer. The relative 5-year survival of younger men with or without cancer tends to be greater than that of older men, because younger men have a longer life expectancy.
Lastly, the features in the tumors diagnosed in the younger men were different: they were usually poorly differentiated, metastasize early, had lytic rather than sclerotic bone metastases, and responded poorly to hormonal therapies. This suggests that these tumors may have different biology from the garden-variety prostate cancers. Although the authors discuss possible factors that could contribute to the increasing rate of prostate malignancies diagnosed in younger men, the cause is unknown.
Thus, the “bottom line” is that that there are now two age peaks associated with advanced prostate cancer: one in men aged 25-40 years and the other in men aged 70 years and older.