Faculty Bibliography

Risk of breast cancer following radiation exposure was studied, based on surveys of tuberculosis patients who had multiple fluoroscopic examinations of the chest, mastitis patients given radiotherapy, and atomic bomb survivors. Analysis suggests that the risk is greatest for persons exposed as adolescents, although exposure at all ages carries some risk. The dose-response relationship was consistent with linearity in all studies. Direct evidence of radiation risk at doses under 0.5 Gy (50 rad) is apparent among A-bomb survivors. Fractionation does not appear to diminish risk, nor does time since exposure (even after 45 years of observation). The interval between exposure and the clinical appearance of radiogenic breast cancer may be mediated by hormonal or other age-related factors but is unrelated to dose. Age-specific absolute risk estimates for all studies are remarkably similar. The best estimate of risk among American women exposed after age 20 is 6.6 excess cancers/10(4) WY-G-Y (10(6) WY-rad)

A case-control study of the relationship between hair dye use and breast cancer included 129 breast cancer patients and 193 control women drawn from the records of a multiphasic screening clinic. Information was obtained by telephone interview on a number of risk factors for breast cancer and on variables pertaining to hair dye use: chronologic time, duration, frequency, type, and color. From this, quantitative measures of cumulative hair dye use at various intervals prior to breast cancer (or an equivalent for controls) were obtained. A multivariate risk factor score was used to control for confounding variables. The adjusted relative risks for breast cancer versus hair dye use were greater than unity but were not generally significant. However, integral measures of hair dye use (No. of yr times frequency per yr) were significantly related to breast cancer when confounding variables were controlled. The association between hair dye use and breast cancer was greatest among women over 50 years of age and among those at lower natural risk for breast cancer. An analysis of temporal patterns showed that breast cancer was related mainly to hair dye use 10 or more years before cancer diagnosis. Because of the retrospective nature of the hair dye data and the small sample size, these results require further validation.

To investigate the late effects of radiation to the head upon subclinical mental disorders, a psychiatric and psychometric evaluation was performed on 177 cases treated 10-29 years earlier for ringworm of the scalp by X-ray therapy (N :109) or, by chemotherapy (N :68). Analyses which controlled for educational level and family psychiatric disorders showed that, among whites, the irradiated group manifested more psychiatric symptoms and more deviant MMPI (Minnesota Multiphasic Personality Inventory) scores. They were also judged more maladjusted from their MMPI profiles, and more frequently had a history of treated psychiatric disorders; however, the psychiatrist's overall rating of current psychiatric status showed only a borderline differnece between the two groups. There were no significant differences between irradiated and chemotherapy treated blacks.