I found out last night an old high school friend is in his last days dying of lung cancer. Thing is this guy never smoked. Ever.
I am so conditioned to the theme that lung cancer is caused by smoking I have missed the fact that non smokers have this also.
Just what is the % of non-smokers who will get lung cancer, verses the % of smokers?
My father died of lung cancer at age 80. Although he had smoked, he had not smoked for 40 years. It was Bronchioloalveolar Carcinoma, and the doctor told him that there was no statistical link between this type of cancer and smoking. It is a fairly rare kind of cancer.
I haven’t done any recent research on this, but at the time (2000) the doctor appeared to be correct.
I was surprised it was such a high number - like you I’ve always thought of it as a “smokers disease”. *
*I don’t mean that in a bad way, just meant that I associate it with smoking.
I don’t know, was he around someone who smoked a lot or was he married to someone who smoked? I believe people can acquire lung cancer from second-hand smoke if they are exposed to it frequently. I had smoked a lot when I was younger, and although I feel basically OK health-wise, I wonder if I may get lung cancer at some point. To be honest, I have about four or five cigarettes (not packs) a year now. I still think about Dana Reeve, and what a lovely woman she was, and that she too, like your friend, had never smoked and got lung cancer. I have often wondered why exceptional people like Dana Reeve are taken from us, when she did so much good, and she was such a fine person.
I might be wrong here, and I’d gladly be corrected, but this is the way I understood it:
Secondhand smoke is also a Category 1/Class A carcinogen. There is no safe level of secondhand smoke. In that sense, there are probably almost no “non-smokers” in the world. If someone gets cancer that can be caused by smoking, but they never smoked in their life, how would you know if it was caused by secondhand smoke?
So then how do we read the 16,000-24,000 non-smokers who die of lung cancer? The cite (thanks Fluffy) says 3,400 people die of secondhand smoke, but everyone breathes some secondhand smoke. I don’t know how that works.
Different matter if it’s a kind of cancer that is not caused by smoking, of course.
Cecil on second-hand smoke:
Some basic data about Lung cancer risks from UpToDate.com:
RISK FACTORS — A number of environmental and life-style factors have been associated with the subsequent development of lung cancer, of which cigarette smoking is the most important.
Smoking — The primary risk factor for the development of lung cancer is cigarette smoking, which is estimated to account for approximately 90 percent of all lung cancers.
Radiation therapy — Radiation therapy (RT) can increase the risk of a second primary lung cancer in patients who have been treated for other malignancies.
Other factors — A number of other factors may affect the risk of developing lung cancer:
Environmental toxins — Environmental factors have been associated with an increased risk for developing lung cancer. These include exposure to second-hand smoke, asbestos, radon, metals (arsenic, chromium, and nickel), ionizing radiation, and polycyclic aromatic hydrocarbons.
Pulmonary fibrosis — Several studies have shown that the risk for lung cancer is increased about sevenfold patients with pulmonary fibrosis. This increased risk appears to be independent of smoking.
HIV infection — The incidence of lung cancer among individuals infected with HIV appears to be increased compared to that seen in uninfected controls.
Genetic factors — Genetic factors can affect both the risk for and prognosis from lung cancer. Although the genetic basis of lung cancer is still being elucidated, there is a clearly established familial risk.
Dietary factors — Epidemiologic evidence has suggested that various dietary factors (antioxidants, cruciferous vegetables, phytoestrogens) may reduce the risk of lung cancer, but the role of these factors is not well established.
I have a friend who has lung cancer, mesothelioma, virtually always associated with asbestos. He was once in the navy and presumably that was where he was exposed. He has an estimated 2 years to live and is going to enjoy them as long as he is able.
Here’s a breakdown of lung cancer types and the percentages caused by smoking vs other causes.
there is more to cancer than just exposure. Look at someone like George Burns, he smoked cigars for something like 90 years never had cancer AFAIK. I never took a puff of tobacco in my life and seldom drink but yet I got throat cancer at age 50. I am sure genetics plays a role as well as exposure. I was around second hand smoke growing up. No hijack intended from lung cancer topic.
I don’t know the stats you are asking about, but sadly, I’ve recently learned that (and this is VERY abbreviated) there are sort of two types of lung cancer (more than that, but this is abbreviated, like I said):
There is the type you get from smoking, and there is the type you get from being, I guess, unlucky. The terms you usually hear to describe them are small-cell and large-cell.
The smoker’s type (also second hand smoke) is typically diagnosed at late stage or end stage. This is generally the type that you hear about when someone goes into the doctor with bronchitis and find they have stage 4 with three months to live. By then the disease has traveled to brain and other organs. Treatment typically is life-extending and palliative, but not curable. (Obv there are ALWAYS exceptions)
The type of cancer that non-smokers get is usually slow-growing. It is often found earlier, before stage 3 or 4, and it’s often completely curable, usually with excision of part of the lung, chemo and radiation.
Non smokers can get the smoker type, and smokers can get the non smoker type. A friend of mine who was a heavy smoker was diagnosed with lung cancer, and it turned out to be the slow-growing type. She’s now in remission/cured.
A smoker’s risk of getting the fast growing cancer drops every year after they stop smoking.
There are other types of lung cancer, but I’m not at all educated on those.
The moral of the story is: don’t smoke. See your doctor immediately if you have a lingering cough.
Actually, it’s more complicated than “smokers’ type” and “non-smokers’ type” of lung cancer.
The previous poster referred to small cell carcinoma, which is highly correlated with smoking (an absence of smoking history makes me cautious about rendering this diagnosis on a biopsy). Other lung carcinomas are classified as non-small cell carcinomas (within this category, so-called large cell carcinomas are poorly differentiated as compared to the more common non-small cell tumors (adenocarcinomas and squamous cell carcinomas, both of which are more prevalent in smokers). Smoking is also a risk factor for large cell carcinomas (about 2-4 times as common in smokers compared to nonsmokers)
Sometimes the cancer cells are in your system already, Not necessary that only smoker‘s die of cancer there are thousands of people suffering from cancer without doing anything .Most of the time cancer cells are there in the human body but it symptoms are found out to be later, but if detected at an early stage then the chances of curing the cancer are more precise.
Thank you for fleshing out my admittedly abbreviated comment for them that like more specificity.
My great uncle died of lung cancer when he was in his late 70’s. As far as I or my mom know, he never smoked, but maybe he had long ago. He was obsessed with spraying this apple tree for bugs and in his youth he’d eaten a lot of smoked meat.
In terms of cause and effect we know that there’s always another factor involved in lung cancer besides cigarette smoking. It may be genetics, a virus, or other environmental factors (or something else maybe). However the vast majority of cases of lung cancer are related to cigarette smoking. Unfortunately some people will develop lung cancer even if they’ve never smoked a cigarette in their life, or even been exposed to any cigarette smoke. But maybe someone who never smokes, doesn’t live in a high pollution area, and takes very good care of themself would have only the slimmest chance of developing lung cancer. I’ve been looking at information on this for years, and it’s difficult to get exact numbers everyone agrees on, but it’s obvious that at a bare minimum 75% of lung cancer cases are strongly related to cigarette smoking, and I suspect it’s a much higher number than that, and the lower numbers are based on someone’s agenda or a misinterpretation of legitimate research.
And for any kids out their reading, just don’t smoke. You aren’t guaranteed to get lung cancer from smoking, but it’s close to a guarantee that you’ll end up with some type of heart or lung disease or other forms of cancer.
I remember Dana Reeves, Christopher’s wife, Superman, died of LC and she never smoked, it was said.
What, you never watched* Breaking Bad*? 
One thing to note about lung cancer in non-smokers (that I don’t think has been mentioned in this thread, but apologies if it has) is that they tend to be responsive to a new class of anti-cancer drugs called tyrosine kinase inhibitors and related agents. (Brief, lay overview of tyrosine kinase inhibitors; more advanced summary; nice looking slide presentation at a fairly sophisticated level.)
Here is one of a number of recent articles discussing the observation that lung cancers in non-smokers have mutations in the gene for their epidermal growth factor receptors, and its implications for therapy (i.e. good news).
Bottom line is that non-smokers’ lung cancers tends to have mutations in the gene for the epidermal growth factor receptor, and that makes them sensitive to tyrosine kinase inhibitors. In other words, in non-smokers with lung cancers, there’s a real shot at control of the disease using drugs of that class. It’s also worth noting that as a class, tyrosine kinase inhibitors tend not to have a lot of dreadful side effects (in contrast to more traditional chemotherapeutics agents).