Final answer:
Cancer-related cachexia is a multifactorial syndrome causing weight loss and muscle atrophy in cancer patients. It involves systemic inflammation and catabolic metabolism. Animal studies also indicate that calorie restriction might reduce tumor growth and extend lifespan, possibly due to less oxidative DNA damage.
Step-by-step explanation:
Cancer-related cachexia is a complex syndrome characterized by severe body weight loss, muscle atrophy, fatigue, and poor appetite among other symptoms. It is particularly frequent in patients with cancer, AIDS, congestive heart disease, or some liver diseases. In cancer, cachexia's mechanism is multifaceted, involving systemic inflammation, catabolic metabolism, and immune system dysregulation. Although the exact pathways are not entirely understood, these factors lead to accelerated breakdown of muscle protein and fat stores, despite adequate calorie intake.
Animal studies have suggested that reducing caloric intake by 30% can slow down tumor growth and extend the lifespan of the subjects. It is hypothesized that a restricted caloric intake may lead to less oxidative damage to DNA, which can be beneficial. However, cancer cachexia is actually more correlated to metabolic changes rather than caloric intake.
Chemotherapy, a common cancer treatment, also impacts cachexia by damaging rapidly dividing cells, which include not only cancer cells but also healthy cells like those in the skin, hair, gastrointestinal tract, and bone marrow. Newer therapies aim to enlist the immune system to specifically target cancer cells, mitigating some of the damage to normal cells, but these approaches are still under investigation and development.