—The article by Finnerty et al1 on radiation-induced breast cancer was a laudable attempt to elucidate the characteristics of a subset of breast malignant neoplasms. Unfortunately, flaws in the study design and analysis cast doubt on its conclusions.
The article analyzed 16 women irradiated before the age of 23 years for a variety of conditions. The women represented 1.7% of 912 breast cancer patients seen at a major Texas referral center. Data collected did not include such known breast cancer risk factors and variables2 as parity, family history, benign breast diseases, and histopathologic cancer type. Incomplete data on total dose, fractionation, and localization of the therapeutic X-ray beam in relationship to the breasts preclude radiation dose quantitation.
The authors refer to their patients as suffering from radiation-induced breast cancer, despite unconvincing evidence. Their cases were identified retrospectively from a large, uncontrolled cohort, an epidemiologic approach that yields