Most lung cancers start in the cells that line the bronchi, and can take years to develop. is that true?

My dad recently died of small cell lung cancer chemotherapy complications neutropenic sepsis infection. he was paraplegic for 24yrs smoked for 35yrs and spent most of his time in bed. 4yrs ago he stoped smoking but he had a heart attack in august 08 and 5 months later he was diagnosed with sclc cancer. he had lots of problem with digestive system between that time and he was feeling depressed , i thought he was near another heart attack. i would like to know whether heart attack and depression contributed- triggered the cancer to form or did it start years before due to smoking?

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Answer:
the cancer started forming years earlier, the only time that the body becomes 'aware' of the cancer is when it's growth is big enough to cause symptoms, or to be found as nodule, or growth. Cancer starts as normal human cells, therefor the body doesn't mind it until it's large enough to disturb the other tissues around it either by pressure or cutting off the normal tissue's blood supply. Smoking is thought to cause cancer by repeatedly exposing the lung tissue to cancer causing agents. Lung cancer can also be a secondary cancer, because all of the body's blood filters through the lungs and cancerous cells from other parts of the body can accumulate there. Sometimes heart attacks can predispose us to more frequent medical care and other conditions or diseases are found. A heart attack alone can cause depression, and your father had many reasons to be depressed related to his health. Sepsis is not unusual related to chemotherapy because so much of the body's immune system is destroyed while killing the cancer, and infections that we could normally fight off are lethal. If you need more answers or support, I encourage you to seek out a chapter of the American Cancer Society close to you. They have support groups for surviving family members where you can find the help you need.

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Answer:
here is a research group…. you can ask questions on their message board http://boinc.bakerlab.org/rosetta/