Stephen J.LurieMD, PhD, Contributing EditorIndividualAuthorPhil B.FontanarosaMD, Executive Deputy EditorIndividualAuthor
To the Editor: The relative risks (RRs) reported
in the retrospective study by Dr Schairer and colleagues1
are too small to claim a causal relationship. The clinical significance of
the minimally elevated RRs cannot be interpreted as excess or attributable
risk without incidence data. Assuming a yearly RR of 0.12 and an annual breast
cancer incidence of 1 case per 1000, only 12 additional cancers would be diagnosed
each year for every 100,000 women treated with estrogen and progesterone.
No additional breast cancer deaths would occur (Schairer et al2
previously confirmed improved breast cancer survival with HRT) while many
cases of osteoporosis would be prevented each year.
Del Priore G, Lee M. Estrogen-Progestin Replacement and Risk of Breast Cancer. JAMA. 2000;284(6):691-694. doi:10.1001/jama.284.6.691