Oncology · 1971
Health Insurance Plan (HIP) of Greater New York mammography trial
Health Insurance Plan of Greater New York
By the mid-1960s, breast cancer was the leading cause of cancer death in American women, yet there was no evidence that finding tumors earlier actually reduced mortality. Observational studies had produced encouraging signals, but lead-time and length-time bias made them impossible to interpret. What was needed was a randomized trial with death, not detection, as the primary outcome.
Philip Strax, a radiologist whose own wife had died of breast cancer, approached the Health Insurance Plan of Greater New York with a proposal for exactly that trial. Working with surgeon Louis Venet and biostatistician Sam Shapiro, Strax recruited roughly 31,000 women aged 40 to 64 and offered them annual mammography combined with clinical breast examination; a matched group of approximately 31,000 women received usual care with no additional screening. The study launched in 1963, and Strax, Shapiro, and Venet published their principal mortality results in JAMA in 1971.
After roughly seven years of follow-up, breast cancer mortality in the screened group was approximately 30 percent lower than in controls, with the reduction concentrated in women over 50. The finding was not subtle enough to attribute to chance, and it answered the core methodological objection: this was a randomized trial with mortality as the endpoint, not a case series of stage distributions. Earlier detection, in at least some women, was translating into fewer deaths.
Criticism of the trial was substantive and persisted for decades. The intervention combined mammography and physical examination, so the independent contribution of mammography alone could not be isolated. The equipment used was far inferior to later technology, and compliance was incomplete. A sizable proportion of women in the control group eventually obtained mammography on their own, diluting the between-group difference. These limitations made the HIP results suggestive rather than conclusive, and they drove the design of subsequent Swedish and British trials.
Despite those caveats, the HIP data provided the primary evidence base for the earliest U.S. recommendations to offer routine mammography screening. The American Cancer Society began recommending screening mammography in the 1970s partly on the strength of this trial. Later Scandinavian trials confirmed mortality reductions in older women, though the magnitude and the threshold age for benefit remain debated in guidelines to this day.
Key People
- Philip Strax — Radiologist who designed and directed the HIP breast screening program.
- Sam Shapiro — Biostatistician who led the analytical design and outcome assessment for the HIP trial.
- Louis Venet — Surgeon and co-investigator in the HIP mammography screening program.
JAMA 1971;215:1777-1785
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