What causes breathlessness and weakness when having cancer?
Patient: I was recently diagnosed with colon and liver cancer.  Had a bowel resection 6 weeks ago.  I was going to start chemo, but came down with shortness of breath and feeling weak.  Went to emergency room and was tested for blood clots.  Had EKG's and wore a heart monitor.  That was normal.  I started feeling better and was discharged.  Symptons are back.  Wondering what it might be. Doctor: Hi,Thanks for writing in.Chemotherapy is treatment with strong medicines which kill the cancer cells. Since you are having colon cancer with liver involvement therefore its possible that you are taking combination chemotherapy. This involves more than one chemotherapy agent and might be aggressive in action. When chemotherapy works then the cancer cells get destroyed in large numbers. These deal cells are mobilized in circulation and cause side effects like weakness and fever as there is release of low amounts of toxin.Some chemotherapy agents also cause toxicity to the lungs and muscles and please discuss this with your doctor. You must also get liver and kidney function tests repeated to know if there is any abnormal function due to taking chemotherapy. Please do not worry.