The New York State Department of Health just published state breast cancer rates by zip code. Itís good news for personal injury lawyers, activists and taxpayer-dependent researchers. For women and families concerned about breast cancer, however, mapping of cancer rates is an exercise in geo-statistical futility. For homeowners, itís a nightmare.
The mappingís purpose is to identify geographic areas -- "clusters" -- where breast cancer rates are higher. The information will focus research on possible local environmental causes of the clusters. The plan seems logical; itís not.
The saga starts in Long Island which has a "high" breast cancer rate compared with the rest of the state. But itís not clear anything special is occurring, according to Marilie Gammon, a Columbia University statistician who leads a federal study of Long Island breast cancer.
The Long Island rate is no higher than other places with similar populations of affluent, educated white women. For unknown reasons, thereís more breast cancer among such women than among black or Hispanic, poor or rural women. So Long Island rates only appear to be high.
The Centers for Disease Control and Prevention concluded in 1993 that Long Islandís higher incidence of breast cancer could be explained by known risk factors, including a larger population of Jewish women, an older population and a higher median age at first birth. The CDC said pollution, pesticides, electromagnetic fields and hazardous waste sites were not known to induce or promote breast cancer.
But the CDC report wasnít good enough for then Sen Alphonse DíAmato, who called it "superficial and inadequate." Sen. DíAmato pressured the federal government to spend $21 million studying breast cancer on Long Island.
The New York state legislature in 1998 required the development of county-by-county cancer maps. Gov. George E. Pataki at first vetoed the project. Real estate interests and industries responsible for pollution lobbied against the maps, fearing lower property values and lawsuits. In the face of criticism from activists, Pataki okayed the mapping project.
The new breast cancer map isnít getting Gov. Pataki off the hook, however.
Assemblyman Richard Brodsky called the maps "useless." "They donít really identify cancer clusters, which occur at the neighborhood level, well below the zip code level. And they havenít told us about the environmental factors," Brodsky said.
But more detailed mapping is unlikely to be more useful.
Geographic "clusters" of cancer occur randomly. Indeed it would be unusual for all areas to have precisely "average" rates of breast cancer. Simply by chance, cancer rates vary by location. And, despite the hype, the difference between Long Island and the rest of New York in breast cancer rates is relatively small -- 10 to 20 percent
Past efforts to tie cancer clusters to toxic waste sites or pollution have failed. Efforts to tie breast cancer with environmental exposures to chemicals -- notably pesticides, PCBs and dioxins -- also have failed. "Geographic variation in breast cancer rates at the state or regional level is unlikely to be due to region-specific differences in [pollution]," concluded a 1997 study published by Harvard researchers in the Journal of the National Cancer Institute.
The basis for this conclusion is evident from all the breast cancer risk factors considered in the study, including age, menopausal status, age at menopause, age at menarche, parity, age at first full-term pregnancy, use of oral contraceptives, use of postmenopausal hormone therapy, family history of breast cancer, history of benign breast disease, height and weight.
More breast cancer could be diagnosed among Long Island women because, as a better educated and more affluent population, they have better access to, and can afford better medical care.
But donít expect the politicians to stop wasting taxpayer money on cancer mapping.
Environmental activists wonít give up the anti-chemical jihad. Belief in an environment-breast cancer link is unwaivering for many in Long Islandís politically powerful breast cancer lobby. Trial lawyers look to benefit from lawsuits against industrial facilities located in zip codes with high cancer rates. Researchers on the taxpayer gravy train will urge endless study.
Meanwhile, homeowners will suffer as home values vary by zip code cancer rate. Worst of all, no progress will be made in the battle against breast cancer.
Mr. Milloy is a lawyer, biostatistician, publisher of Junkscience.com and adjunct scholar at the Cato Institute.