What is the primary cause of death in cancer patients?

The primary cause of death in cancer patients is often related to metastasis that invades key organs. Metastasis refers to the spread of cancer cells from the original (primary) site to other parts of the body, where they can establish new tumors in vital organs such as the lungs, liver, brain, and bones. This spread can severely impair the function of these organs, leading to life-threatening complications.

When cancer metastasizes, it can disrupt critical physiological processes, such as respiration and blood circulation, or hinder the body's ability to filter toxins, digest food, or regulate vital functions. This organ involvement contributes significantly to the morbidity and mortality associated with cancer, making it a central factor in determining patient outcomes.

While local tumor growth and secondary infections can complicate a cancer patient's health and contribute to mortality, the systemic effect of widespread metastatic disease plays a more pivotal role in the overall decline observed in cancer patients. The natural aging process is also a factor in patient health; however, it is not exclusive to cancer and does not specifically contribute to cancer-related mortality.