Reply #157: That link is about bronchoalveolar carcinoma, from 2001: a later study ties that to smoking

[muriel_volestrangler]

The relationship between cigarette smoking and BAC has long been heavily debated. Data from the 1950s indicate that BAC (and other lung adenocarcinomas) was not related to cigarette smoking at the time. While it is now established that cigarette smoking is strongly related to lung adenocarcinoma, BAC was not separated from other adenocarcinoma subtypes in studies that demonstrated this to be the case. While two case-control studies reported a decade ago did demonstrate a relationship between BAC and cigarette smoking, small sample size and other methodologic problems indicate the need for further studies. Accordingly, we conducted a larger case-control study to evaluate this relationship.
...
We conclude that risk of BAC is now strongly related to a history of ever-smoking cigarettes, and that risk is present in both current and former smokers. While smoking is not the only cause of BAC, our data indicate that approximately 70% of BAC is currently attributable to cigarette smoking.

http://www.asco.org/ASCO/Abstracts+&+Virtual+Meeting/Abstracts?&vmview=abst_detail_view&confID=23&abstractID=104565

So the "bronchioalveolar carcinoma, a non-smoking related lung cancer of unknown origin" in your news story seems more doubtful, now. I don't know where "a similar malignancy in humans that accounts for 25 percent of lung-cancer cases in the United States" comes from - since bronchioalveolar carcinoma is the only one named, I had to presume it means that, but:

Representing 2 to 6 percent
of primary pulmonary malignancies, the relative rarity
of bronchoalveolar carcinoma has delayed its accurate
description by limiting the extent of clinical experience
within individual institutions.

http://medind.nic.in/laa/t05/i2/laat05i2p60.pdf

BAC in its "pure" form represents only 2% to 3% of all NSCLCs, making it a relatively rare entity, so accruing patients to prospective trials is difficult. However, what we've noticed is that there are many adenocarcinomas that contain pathologic features of BAC, and these tumors, even if they are mostly adenocarcinomas, behave more like BAC. So a working definition for oncologists may be a much broader population than the rigorous definition that BAC would imply. If one uses this clinically driven classification and includes adenocarcinomas with BAC features with the pure BACs, then it can be a rather common entity; some pathologists have estimated that there's some BAC in almost half of the adenocarcinomas in the United States.

http://www.medscape.com/viewarticle/498197

From 2001 (before the larger study I linked to) we have:

Bronchoalveolar carcinoma is one of the subtypes of adenocarcinoma in non-small cell carcinoma of the lung. It represents approximately 10 to 25% of the adenocarcinoma of lung cases. Cigarette smoking does not appear to correlate with this type of cancer.

http://www.oncolink.com/experts/article.cfm?c=3&s=19&ss=50&id=1522

There are two main types of lung cancers: around 20% are small cell lung cancers (SCLC) and the remainder are non-small cell lung cancers (NSCLC).

The main types of NSCLC are squamous cell carcinoma, adenocarcinoma and large cell carcinoma, which account for approximately 35%, 27% and 10% of all lung cancer cases respectively in the UK6.

While cigarette smoking has been linked to all four types of lung cancer, adenocarcinoma, is the most common type in non-smokers18 and a rise in incidence has been reported in the USA and other countries7-9.

In the USA, adenocarcinoma is now the most common type of lung cancer. In Europe the most common type of lung cancer is still squamous cell carcinoma despite increases in the incidence of adenocarcinoma9. The increasing incidence of adenocarcinoma has been linked to low-tar cigarettes10.

http://info.cancerresearchuk.org/cancerstats/types/lung/incidence/

so I suggest the journalist at Science Daily has either taken the figure for all adenocarcinomas, or the occurrence of BAC in adenocarcinomas (and taken the upper limit of that estimate), and incorrectly used that as the proportion of all lung cancer that is BAC. Again, using figures produced by journalists, rather than researchers, is a bad idea.

Fact is, "they" are the major experts on cancer, who look at many studies before producing their figures. If you need yet another example of this:

Smoking accounts for at least 30% of all cancer deaths
and 87% of lung cancer deaths.8,9

8. Doll R, Peto R. The Causes of Cancer. New York, NY: Oxford
Press; 1981.
9. US Department of Health and Human Services. Reducing the
Health Consequences of Smoking: 25 Years of Progress. A Report of
the Surgeon General. Rockville, MD: U.S. Department of Health
and Human Services, Public Health Service, Centers for Disease
Control and Prevention, Center for Chronic Disease Prevention
and Health Promotion, Office on Smoking and Health; 1989.

Cancer Facts & Figures 2008 - American Cancer Society

These are the leading governmental and medical authorities on the statistics of cancer and tobacco. These figures are not 'from their ass'.