We do not wish to engage in an historic or semantic debate with Drs. Silverstein and Lagios regarding the genesis of the Van Nuys Prognostic Index. However, I cannot find the use of the word “unsatisfactory” anywhere in our publication1 concerning the Van Nuys Pathologic Classification. Indeed we utilized the word “expanded,” which they also indicate in their letter. Actually, one of the definitions of unsatisfactory is inadequate.2 As I understand their comments, the pathologic classification was indeed inadequate and therefore was expanded. Drs. Silverstein and Lagios indicate in their letter and I quote “The VNPI was not a histopathologic classification and therefore not a modification of our previous classification, and it clearly was not meant to replace it.” It is not indicated in our publication that this was the intent of the VNPI. Yet, one might argue that the VNPI really is a pathologic classification because estimation of tumor size often is histopathologic, as is assessment of the extent of excision. Drs. Silverstein and Lagios also state that the “The VNPI was devised as a treatment planning aid to be used in conjunction with clinical experience, published data from both prospective and retrospective studies, and patient wishes.” First, I know of no truly prospective studies performed by the Van Nuys group. Second, I am somewhat bemused as to where “patient wishes” enter into the development of a protocol for a scientific prospective study or classification of diseases. Indeed, this confession further substantiates our belief as to the actual value of the VNPI (vide infra). I believe Drs. Silverstein and Lagios are overreacting to our observation that we could not find an absolute fit with the Van Nuys Pathologic Classification with our material. They are correct that our use of an absent/slight group of comedo necrosis differs from their recognition of comedo necrosis as simply being absent or present. Our “cutoff” points for comedo necrosis were based on our perception that the significance of comedo necrosis might be quantitative. We have been reluctant to regard the presence of a few ducts containing comedo necrosis as having similar significance to instances in which this process might be far more extensive. Our view is supported by our findings of low and high risk groups for ipsilateral breast tumor recurrence based on the degree of comedo necrosis according to the groups in our algorithm. Actually, I expected such a query and our ongoing pathologic review of ductal carcinoma in situ in the National Surgical Adjuvant Breast Project Protocol B-24 does include an “absent comedo necrosis” category, which might help resolve this issue. I believe the final comments of Drs. Silverstein and Lagios are quite revealing. They, as well as those noted above relating to prospective studies, indicate a certain lack of understanding of prospective clinical trials and their significance. Protocol B-17 was “a treatment protocol” and randomization was not based on any pathologic characteristics. These latter obviously were “retrospectively” obtained. This type of retrospective examination is not to be devalued because it certainly allows for the bona fide recognition of subsets of patients in various treatment groups. Conversely, Drs. Silverstein and Lagios “boast” that their pathologic findings were collected “prospectively and delineated from the onset.” However, and most important, treatment was not randomized on the basis of such findings but unfortunately was based on bias provoked by the pathologic characterization of the tumors—a most injudicious practice for evaluating treatment. Edwin R. Fisher M.D.*, * Headquarters Pathology, National Surgical Adjuvant, Breast and Bowel Project (NSABP), Allegheny General Hospital, Continuing Care Center, Pittsburgh, Pennsylvania