What negative health consequences are associated with cancer radiation and/or cancer surgery?

Depends on type.: Cancer treatment is usually divided into local (the organ where the cancer started) and systemic (the rest of the body) therapy. Both surgery and radiation therapy are local rx's--their side effects are dependent on which organ is being treated. Which specific cancer type are you referring to?

Depends on site: The effects of radiation are totally dependant on the part of the body being treated, except mild to moderate fatigue is common to all sites. Reddening of the skin is common; nausea or diarrhea if the abdomen is treated. Burning sensation on urination if the pelvis is treated. Sore swallowing and dry cough if the chest is treated. Dry mouth and sore throat if the throat is treated.