CHE Cancer Call Notes – September 22nd, 2006

This teleconference was a discussion about important new developments in cancer epidemiology, including the new "Report to the Nation" on U.S. cancer data that has recently been in the headlines.  These statistics can be found on the American Cancer Society website, at: http://www.cancer.org/docroot/STT/stt_0.asp.

Dr. Richard Clapp, D.Sc., Professor, Boston University, School of Public Health, Adjunct Professor, University of Massachusetts, Lowell School of Health and Environment and co-author of Environmental and Occupational Causes of Cancer, a review of recent scientific literature started the conversation by introducing Tables 2 and 3 from the report.

Dr. Clapp’s first point was that these two tables, not mentioned in press statements, are very important for cancer statistics because they include adjustments based on delays in reporting, which changes the perception of the trends.  Looking at these tables, the overall cancer trends are flat (not getting better or worse).

Dr. Clapp also commented on specific cancers, mentioning that thyroid, kidney cancer, and some liver cancers in women appear to be increasing, whereas lung cancer appears to have no trend in women.  In men, lung cancer seems to be decreasing, probably due to reduction in smoking and occupational exposures.  Non-Hodgkin’s Lymphoma in males appears to be flat, although liver, prostate, kidney, and myeloma continue to increase.

From the SEER data, Dr. Clapp commented that Mesothelioma (a cancer known to be caused by asbestos, although Devra Davis noted that there is evidence suggesting that mesothelioma is caused by other environmental factors as well), has not gone up or down, but that childhood cancers continues to steadily increase.  He also noted that mortality rates have gone down, largely driven by the reduction of lung cancer in males and more effective treatment.

Dr. Clapp’s final comments were that we have not made much progress, that the data is complicated, and stressed the importance of tracking cancer rates.

Devra Davis, Ph.D., MPH, Executive Director, Center for Environmental Oncology, University of Pittsburgh, commented that age adjustments are also very important to consider when looking at the data.  For example, when looking at age specific data for 54 to 65/70 year olds, there has been an almost 50% increase of Non-Hodgkin’s Lymphoma in men and women over the last 15 years, which is completely obscured when looking at the age adjusted graphs.

Breast cancer in the age specific range of young women under 40 and 30 is increasing, but this gets washed out when looking at women under 50 (vs. over 50).  In addition, many cancer registries do not include DCIS as a breast cancer – they only include invasive breast cancer.  These change the data.

Other Comments on Statistics
Susan Braun, Founder of the Institute for Women’s Health at Commonweal, commented that it looks like breast cancer has decreased by a little bit in the last several years, but that over the last 20 or 30 years it has increased markedly. DCIS (in situ) breast cancer has grown in the last two decades, and so have

She also asked if Dr. Clapp believes the quality of data for pediatric cancers (which you can find in the SEER data) to be as good as for adult cancers? Dick commented that they are probably more accurate than state registries that are not a part of the SEER program.

Dick Clapp also commented that melanoma has decreased in males over the last 3 years, but continues to increase in females (possibly due to sunlight exposure, although Devra Davis commented that PBBs have also been associated with melanoma).

Ted Schettler commented on the role of Vitamin D deficiency in skin cancer. Devra Davis also commented that clinical trials are currently underway to see if Vitamin D deficiency might be affecting skin cancer trends.

Ted Schettler, MD, MPH, Director of the Science and Environmental Health Network, commented on the importance of looking at the combination of factors affecting cancer trends in a systematic way.  For instance, looking at diet, carcinogens in the environment, etc.

National and International Cancer Associations  
Michael Lerner commented on the position of the Canadian Cancer Society that focuses on environmental and occupational exposure prevention with regard to cancer, wondering if they are in the minority internationally or not.

Dr. Clapp and Dr. Davis commented that the Canadian Cancer Society is not alone in the international environmental public health world, but that the American Cancer Society in the U.S. takes a more uniquely conservative approach.

Next Steps
•    CHE Cancer participants may be interested in developing a consensus statement, similar to the statement written by the CHE Breast Cancer Working Group. We can explore this in the future.
•    Dr. Clapp recommended a documentary, called “The War On Cancer,” which aired in France earlier this year.
•    Devra Davis recommended coordinating a specific group to look at some of the statistics from the report.
•    We may try to have someone from the Canadian Cancer Society or other big cancer organizations on our next CHE Cancer Call to talk about moving the dialogue forward about environment and health with national cancer groups.