Chemotherapy and radiation therapy are known to cause fatigue and weakness as side effects. Chemotherapy drugs target rapidly dividing cells, which includes not only cancer cells but also healthy cells in the bone marrow, digestive tract, and hair follicles, leading to overall physical decline. Radiation therapy, while localized, can also damage healthy tissues, causing cumulative fatigue. Surgery for cancer can lead to a prolonged recovery period where patients may experience weakness due to the invasive nature of procedures.
