A friend died today of lung cancer. Non-smoker, didn’t work around chemicals or in workplaces with a lot of smoke; she was a librarian.
I thought lung cancer was triggered almost entirely be environmental factors?
Cigarette smoke is just a more concentrated form of air pollution, which has been implicated in a significant number of non-smoker lung cancer cases; e.g.:
(in China, air pollution was a factor in 1.2 million deaths in 2010, and only around 11% were respiratory cancers, so like cigarette smoking, lung cancer is just one of the health risks from air pollution)
My gramma died of lung cancer. She never smoked. It began as breast cancer and spread to her lymph nodes, then lungs. This is fairly common actually.
I thought it was established that some cancers begin as ordinary mutations of cells within the body, i.e., not caused by outside causes, but simply by internal spontaneous mutation.
Of course, there are also things like radon gas, or cosmic rays, which are outside causes, and can pretty much get anybody, anytime.
Indeed. I recall a friend who smoked heavily, but developed brain cancer. It did her in. The autopsy indicated that. There were no problems with the lungs.
Rest well, Suzanne. I miss you.
Correct. Keyword bolded.
Going just by your description, she didn’t die of lung cancer. She died of metastatic breast cancer, which had spread to the lungs among other places. Different situation.
And something similar might hold true for the OP. For all we know, the “lung” cancer might have “sprouted” from metasteses from some other site.
Sometimes, people with no discernible risk factors get sick anyway. Lung cancer existed before the invention of smoking.
Smoking drastically increases the risk of lung cancer, to an extent that you can arguably say it caused it in a given patient perhaps, but it is magical thinking to say “since I don’t smoke, I won’t get lung cancer.”
My father died of Bronchioloalveolar cancer, a type of lung cancer with no statistical correlation to smoking.
Based on Lifetime probability of developing lung cancer, by smoking status, Canada - PubMed, about 1.5% of non-smokers develop lung cancer, whereas smokers are ten times as likely to develop lung cancer, 12%-17%.
The one word answer to your question: randomly.
I can’t search right now, but I believe in another thread on lung cancer KarlGuass made the point that the prevalence of non-smoking-related lung cancers have about the same prevalence as other cancers for which there aren’t known risk factors. Apologies to KG if I’m misremembering the point.
Radon.
Asbestos.
Know someone with lung cancer who never smoked and was going crazy searching for the cause. The doctor told him not to beat himself up over it because sometimes it’s just random.
Read about Alice Trillin. She suffered lung cancer from growing up in a home where both parents were heavy smokers, though she never smoked herself.
In his book Remembering Alice, Calvin Trillin wrote about how Alice was willing to discuss their two daughter’s ideas on sex, drinking and drugs with them. “But smoking is not allowed. Period.”
You may recall that Andy Kaufman died of a rare type of lung cancer not associated with smoking.
Similarly, a cancer researcher who shared a Nobel prize for discovering reverse transcriptase, Howard Temin, died of lung cancer at only age 59, and was not a smoker.
Mutation seems to be an essential part of the transformation process. Going from noncancerous to cancerous takes a minimum of three independent mutations, if I recall my old immunology class aright. The problem is, “ordinary” mutations as you describe them here look exactly the same as mutations caused by external causes (radiation, pollution, smoking, etc). There’s really no way to point to specific mutations and say “this one was just caused by a random accident in the cell, and this one was caused by a puff of smoke you took in 2005, and this one was caused by a fungal toxin.” So since all cancers have mutations, and we can’t detect mutation causes, there’s really no way to say how many cancers are caused from “internal” or “external” mutations. We can do gross estimations, by measuring mutation rates in smokers vs nonsmokers, for instance, but that has limited power.
There are a number of different types of cancer that originate in the lungs. Small cell lung cancer is the one usually associated with smoking. There are different types of non small cell lung cancer. Smoking obviously increases your lung cancer risk but is not the only thing that causes lung cancer.