Letters Section Editor: Robert M. Golub, MD, Senior Editor.
In Reply: Dr Crystal questions our assumption that the minimal detectable size of a breast tumor on MRI is 5 mm. However, 5-mm invasive breast tumors have been identified on MRI screening examinations.1,2 In our model, the size at which tumors are detected by screening depends on their minimal detectable size, their growth rate, and the frequency of screening. We found that at the time tumors are screened, most screen-detectable tumors are larger than their minimal detectable size. Our estimate for the tumor size distribution at detection (Table 5 in our article) is consistent with Crystal's summary of published data; however, a statistical comparison is not meaningful due to the small sample sizes in each study.
Plevritis SK, Ikeda DM, Garber AM. Cost-effectiveness of Breast Magnetic Resonance Imaging to Screen. JAMA. 2006;296(22):2681-2682. doi:10.1001/jama.296.22.2682