NIH/ACS are CoRrecT politically, not scientifically

Does smoking cause 87% of all lung cancer?

Jaydad

1) for an individual, it may take 5 years or 50 years from carcinogenic exposure (tobacco smoking for instance) to clinical diagnosis of cancer, but for the population, the very well established average duration is 20-30 years.

2) for the US population, there is CDC in Atlanta documenting the trend of the habit, starting from year 1965. Although there were some blank-data years, existing data are just enough to do some correlation analysis. Let me give you an idea of the TREND - more than half of US men (52%) were 'current smokers' in 1965, but as of 2007, 'current smoker' rates were 22.7% men and 17.4% women.

3) now the simple logic: if smoking causes the majority (51-100%) of one particular type of lung cancer, should we see a delayed (20-30 years delayed) cancer incidence trend that correlates positively with the population smoking rate trend?

4) yes, indeed, there is a near perfect correlation between US population smoking rate and Small Cell Lung Cancer incidence 23 years afterwards (r square 0.97 if you care for the details). Smoking causes the overwhelming majority of SCLC, no doubt about that! for the year 2007, the SCLC number was 28,000 cases.

5) now for the 76,000 cases of female NSCLC 2007, we also have a pretty nice correlation between female population smoking rate and NSCLC incidence at a 26-year time lag (r square being 0.93). Must be wonderful news for some people, but wait! I forgot to mention that was negative correlation. By negative, it means that as smoking rate drops over the decades, female NSCLC incidence actually rises and keeps rising! Here is a slice of that data - in 1965, female population smoking rate was 33.9%, female NSCLC incidence in 1991 (26-year lag) was 40.2 per 100,000; 15 years later in 1980, smoking rate dropped to 29.3%, but female NSCLC incidence in 2006 (same 26-year lag) rose to 46 per 100,000. If you argue that smoking causes majority (>50%) of female NSCLC, I am afraid you are totally out of luck, and out of mind as well.

6) Now let's deal with male NSCLC numbers, 93,000 cases of year 2007. They are broken down to 2 subcategories: adenocarcinoma 36,000 cases and non-adeno carcinomas (large-cell, squamous-cell, and the rest non-adeno pathology types) 57,000 cases.

7) guess what, for male adenocarcinoma incidence, there is no correlation with male smoking rate using 20-30 year lag (r square negative 0.2 for 20-year lag). Are you surprised that tobacco smoking does not cause majority of male adenocarcinoma?

Lets summarize -

28,000 SCLC(M+F), mostly (>90%) caused by tobacco smoking, supported by strong positive correlation;

76,000 NSCLC (F), majority (>51%) NOT caused by tobacco smoking, because of strong negative correlation;

36,000 adenocarcinoma (M), majority (>51%) NOT caused by tobacco smoking, due to absence of correlation;

57,000 other NSCLC (M), majority (>51%) could be caused by tobacco smoking, based on positive correlation.

Total 197,000 cases, 2007

 

References

1. Surveillance for Selected Tobacco-Use Behaviors -- United States, 1900-1994. http://www.cdc.gov/mmwr/preview/mmwrhtml/00033881.htm

2. Wogan GN, Hecht SS, et al. Environmental and chemical carcinogenesis. Semin Cancer Biol. 2004; 14:473-86.

3. Fast Stats - National Cancer Institute Surveilance Epidemiology and End Results http://seer.cancer.gov/faststats/selections.php

4. Melikian AA, Djordjevic MV, et al. Gender differences relative to smoking behavior and emissions of toxins from mainstream cigarette smoke. Nicotine Tob Res. 2007; 9:377-87.

5. Subramanian J, Govindan R. Lung cancer in never smokers: a review. J Clin Oncol. 2007; 25:561-70.

6. National Cancer Institute - Cigarette Smoking and Cancer: Questions and Answers. http://www.cancer.gov/cancertopics/factsheet/tobacco/cancer

7. American Cancer Society - Tobacco-Related Cancers Fact Sheet. http://www.cancer.org/docroot/PED/content/PED_10_2x_Tobacco-Related_Cancers_Fact_Sheet.asp

8. Cancer Research UK - UK Lung Cancer incidence statistics. http://info.cancerresearchuk.org/cancerstats/types/lung/incidence/

所有跟帖： 

• Thanks for sharing. -ooopsss- ♂ (0 bytes) () 10/26/2010 postreply 11:32:06