Aging and Cancer Risk: Understanding the Connection with Immune System Decline

Aging and Cancer Risk: Understanding the Connection with Immune System Decline

Prostate cancer primarily affects older men, with a significant incidence by age 80. Treatment often isn’t urgent due to its slow progression. Aging impacts the immune system’s effectiveness, diminishing its ability to identify and eliminate cancer cells, leading to a higher cancer risk. Research shows that while tumor cell division rates vary, an aging immune system suffers from chronic inflammation, complicating the fight against cancer. Maintaining a healthy lifestyle may help bolster immune function as one ages.

Understanding Prostate Cancer and Aging

Prostate cancer is known for its slow growth rate, affecting men of all ages, although it is notably rare in younger individuals. The primary risk factor for developing this type of cancer is advancing age. “By the time men reach 80, approximately 75% will have detectable prostate cancer,” explains Peter Albers, a urologist from the University Hospital Düsseldorf and the German Cancer Research Center. Albers points out that due to the gradual progression of these tumors, immediate treatment is often unnecessary for older patients; instead, careful monitoring is usually sufficient. Despite ongoing speculation about the reasons behind the slow growth of prostate cancer compared to other malignancies, most patients experience few symptoms and do not succumb to the disease.

The Impact of Aging on the Immune System

As we age, our body’s cells tend to divide at a slower pace. However, current research has yet to definitively determine whether tumor cells also exhibit a decrease in division rates with age. Katja Simon, who studies the interplay between aging and the immune system at the Max Delbrück Center in Berlin, notes that the division rate of cancer cells can vary significantly based on the cancer type and the specific mutations involved.

Cancer typically arises when normal cells accumulate mutations over time, granting them abnormal properties such as unscheduled cell division. When the immune system or treatments fail to eliminate these cancer cells, they can become immortal. Simon emphasizes that there is no expectation for tumor cells to consistently divide more slowly as individuals age.

Unfortunately, the immune system does weaken over time, leading to an increased susceptibility to various diseases, including cancer. An aging immune system struggles to detect and eliminate cancer cells effectively. Additionally, certain immune cells begin to release higher levels of signaling molecules called cytokines, which aim to recruit additional immune cells for assistance, likely due to their diminished functionality.

This elevated cytokine level acts like a persistent alarm for the immune system, causing weakened immune cells to keep the entire immune response in a heightened state of activation. This chronic inflammation contributes to various age-related health issues and accelerates the aging of our organs, including an increased risk of cancer. While immune cells play a significant role in this process, other aging body cells also contribute, a phenomenon known as “inflammaging,” which merges inflammation and aging. The deterioration of the immune system thus has a dual negative impact: a higher cancer incidence and a reduced ability to combat it.

The reasons behind the immune system’s decline with age are currently a prominent area of research, with scientists gaining better insights into the underlying mechanisms. One key factor is that our bodies face an ever-expanding array of pathogens—bacteria, viruses, and mutated cells—throughout our lives. T-cells are crucial for recognizing and remembering these threats; however, as we age, the population of responsive T-cells diminishes, limiting our defense against new challenges. Simultaneously, our immune system becomes increasingly focused on clearing out old, non-functional body cells, leading to a burden that our immune cells struggle to manage effectively.

These age-related changes typically commence around the age of 65. “While significant individual differences exist up to age 75, from that point onward, the immune system’s decline is consistent across all individuals,” Simon notes.

While these prospects for aging may seem daunting, it is possible to bolster our immune system to some extent. Simon suggests that maintaining a balanced diet, engaging in regular exercise, and ensuring adequate sleep can be beneficial. Preliminary evidence indicates that limited calorie intake and occasional fasting may have positive effects on immune health, a topic her research team is currently exploring. Despite the advancements in longevity medicine, the aging immune system can be somewhat delayed but not entirely halted.