BUFFALO, NY - The "not so good news" from a recent study conducted at Roswell Park Cancer Institute (RPCI) is that the incidence rates for two forms of common brain tumors - glioblastoma multiforme (GBM) and anaplastic astrocytoma (AA) - have increased in New York State between 1976 and 1995. The "good news" is that the study may have revealed clues to the origins of GBM; the most common of these tumors.
The study by Brian P. McKinley, MD, Department of Surgery, and colleagues at RPCI, is published in the December 2000 edition of the Journal of Neurosurgery.
The research team used data from the New York State Cancer Registry (NYSCR) to calculate crude, age- and sex-specific incidence rates for each of the three tumor types from 1976 to 1995. Their review of the NYSCR data identified 11,204 cases of GBM, 4,613 cases of astrocytoma not otherwise specified (ANOS), and 878 cases of AA diagnosed during that time period. The results demonstrated statistically significant increases in the age-adjusted incidence of GBM (33% for men, 55% for women) and AA (150% for men, 160% for women); as well as an apparent increase of ANOS (75% for men, 50% for women) which was not statistically significant.
"Our analysis of GBM, ANOS and AA cases confirms that as a group, the incidence of these central nervous system malignancies has increased over the last two decades in New York State," according to Dr. McKinley. The authors are quick to point out that their data cannot fully explain the increased incidence observed in each of these tumors.
"We believe that the dominant reasons for these increases are improved diagnostic methods and a more aggressive diagnostic approach toward the elderly," notes McKinley. "But, we are not willing to rule out changes in environmental exposures, tumorigenesis, or an inherent susceptibility of elderly as being responsible for these observations."
Interestingly, while the incidence of GBM increased in both men and women during the study period, men have an overall incidence of GBM that is one and a half to two times that of women. "This trend toward lower risk of GBM in the female population appears to begin around the age of menarche and to be mitigated by menopause," according to McKinley. The authors report that while other studies have inferred an overall protective effect of female gender on GBM and laboratory studies have also supported the potential role of female sex hormones, their data are the first to demonstrate this effect in a large, population-based study of GBM incidence.
"The combination of these studies and data from our large population-based analysis of GBM incidence should provide the impetus to investigate the potential roles that sex hormones and their metabolites may have in the origins of GBM," the authors conclude. "An analysis of these factors as well as the contributions of genetic differences between the sexes in the pathology and epidemiology of GBM should be pursued aggressively."
Roswell Park Cancer Institute was founded in 1898, is the nation's first cancer research, treatment and education center and is the only National Cancer Institute-designated comprehensive cancer center in Western New York.
Materials provided by Roswell Park Cancer Institute. Note: Content may be edited for style and length.
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