Rachel's Democracy & Health News #999, February 19, 2009


[Editor's introduction: A study of available medical data reveals that cancer is a relatively new disease, which has grown rapidly during the industrial era.]

By Tony Tweedale

[Tony Tweedale runs a consultancy (R.I.S.K. -- Rebutting Industry's Science Through Knowledge) in Edinburgh, U.K. for toxics activists and scientists short on time, finding the most relevant toxicology results. tony.tweedale@phonecoop.coop]

One little-known gem of evidence that cancer incidence has exploded in the industrial era comes from the time of the founding of the USA's National Cancer Institute. I suspected that its founding scientists were very interested in cancer trends, and indeed I found a major study in the first volume of their journal, 1940. I converted and extrapolated their finding of cancer prevalence (rate at a given point in time) of 363/100,000 (0.36%) in the 12 largest USA cities where the best records were,[1] into a rough estimate of national lifetime risk of cancer of 25.4% (assuming a 70 year life) at that time: the 1930's, when toxic emissions were still minor. This study may well be the source of the zeitgeist that I heard as a child in the late 1960's, that cancer would hit "one in four" Americans in their lifetime!

Yet by the early 1990's better estimating methods (since 1973, cancer incidence trend study has eliminated the bias of today's longer life- spans that allowed us to acquire more cancers) show that Americans' lifetime cancer risk rapidly grew to hit almost one in two Americans -- 45% of men and 39% of women(!),[2] where it has since plateaued not mildly decreased, as claimed.[3] In fact, even when cancers that increased due to smoking and better detection are removed, cancer incidence in the USA increased a bit (0.1%/yr) every year, 1975 to 1994, for women but a lot (1.8%/yr)[4] for men (for whom the increase accelerated every year).

Cancer mortality world-wide shows congruent increases among industrialized countries (at least those with registries reliable enough to estimate the trend), even when excluding lung and stomach cancers (tobacco and food causes).[5] The International Agency for Research on Cancer says that even recently (1990 to 2000), cancer incidence increased a full 19% worldwide (and 44% of the 900 agents that IARC has evaluated to date have been classified as possible, probable or actual human carcinogens).[6]

Additionally, most cancer types arise more frequently in the industrialized world than in the less developed world -- a finding replicated in 2000.[7] Many have noted that incidence rates have increased even among the visible cancer types, whose incidence rates have not been falsely inflated by today's imaging technologies that newly detect some internal cancers.

Furthermore, many cancer types have increased drastically in incidence in the American cancer incidence database; relatively few have decreased. Incidence of childhood cancers in the USA has soared 31% since standardization of the USA cancer incidence data in 1973, from about 130 to 170 per 100,000;[8] including a 56.5% increase in brain/CNS childhood cancers and a 69% increase for immune system/blood cancers.[9] Among children through age 19, the overall increase from 1973 to 2000 was 22%.[10] All-age testicular cancer soared 66% from 1975 to 2002. Prostate cancer incidence nearly tripled 1973-1992, and is still 2.5 times its 1972 rate.[11] Breast cancer increased 25.3%, 1975-1996 -- it (including the less risky ductal carcinomas in situ) now strikes at least one in six(!) women of the USA, up from 1 in 14 in the 1960s.[12]

So it seems safe to say that "about half" of Americans today will acquire an invasive cancer, if we extrapolate mildly because the recent huge decline in autopsies, meaning that we are missing significantly more cancers than we did when autopsies were more common.[13]

In short, cancer seems to have about doubled since the early 20th Century. A far more thorough review of the factors influencing changes in cancer incidence has come to the same conclusion.[14] Could it be true?

Practicing for decades as the only care-givers in remote primitive human populations before and as the industrial revolution first developed, several doctors kept careful records of their patients for decades; they found that cancer was all but non-existent in these primitive people:[35] direct if flawed evidence (as they could not compare their findings to urbanized cancer prevalence) that cancer is largely caused by environment!

There seems little doubt -- in the country with the best records -- that well after the smoking cancer surge, but as industrial and other toxin exposures surged and a radical alteration of our diets began (lately even altering food itself!), an explosion of cancer incidence followed. However, cancer in the USA likely didn't quite double overall, because the original "one in four" estimate above missed more cancers than we do today (however they did try to count total prevalence on their area); and because we live a bit longer today, allowing more cancers to occur.

[1] Collins SD et al. Aug. 1940 "Trend & Geographic Variation in Cancer Mortality and Prevalence." J Ntl Cancer Institute:1:4:425-50.

[2] Ntl. Cancer Institute (NCI) 1994 "SEER Cancer Statistics Review, 1971-1991." NIH Pub. No. 94-2789, Bethesda MD.

[3] See Clegg LX, et al. 2002 Oct "Impact of reporting delay and reporting error on cancer incidence rates and trends." J Ntl Cancer Inst.:16;94(20):1537-45.

[4] Dinse GE, Umbach DM, Sasco AJ, Hoel DG, Davis DL 1999 "Unexplained increases in cancer incidence in the United States from 1975 to 1994: possible sentinel health indicators?" Ann Rev Public Health:20:173-209.

[5] Devra L. Davis et al. 25 Aug. 1990 "International Trends in Cancer Mortality in France, ...and the USA." Lancet:336:478-91 (correspondance exchange 336:1262-5).

[6] Cogliano V. Sept. 2004 "The Science and Practice of Carcinogen Identification and Evaluation." Env. Health Perspectives:112:13:1269-74.

[7] International Agency for Research in Cancer (IARC) 2001 "GLOBOCAN 2000-Cancer Incidence, Mortality & Prevalence Worldwide, v. 1.0." IARC Press, Lyon France; available at http://www.dep.iarc.fr/glo bocan/globocan.html (accessed Jan. 2004).

[8] Tracey Woodruff et al. Apr. 2004 "Trends in Env. Related Childhood Diseases." Pediatrics:113:4(suppl):1133-40.

[9] Ntl. Cancer Institute (NCI) 2005 "SEER Stat Database: Nov. 2004 Sub (1973-2004)," available: http://www.seer.cancer.gov.

[10] Same as Note 9: NCI 2005.

[11] Same as Note 9: NCI 2005.

[12] L Ries et al., eds. 2004 "SEER Cancer Statistics Reviews, 1975-2001." Bethesda MD:Ntl. Cancer Institute; available: http://www.seer.cancer.gov/csr/1975_2001/.

[13] Shojania KG et al. 4 June 2003 "Changes in Rates of Autopsy- Detected Diagnostic errors Over Time." JAMA:289:2849-56.

[14] Irigaray P et al. 2007 Dec. "Lifestyle-related factors and environmental agents causing cancer: an overview." Biomed Pharmacother.61(10):640-58.

[15] Stefanson 'Cancer: disease of civilisation?' New York: Hill & Wang; 1960; and V.Z. Goldsmith Mar/Apr 1998 "Cancer: a disease of industrialization." Ecologist:28:2:93-9.