We are pleased that our article1 has prompted Chapman et al. to reexamine their own data from a cohort of patients from the Women's College Hospital of Toronto with breast carcinomas measuring ≤1 cm.2 Chapman et al. found the rate of lymph node positivity for T1a tumors to be 31% (5 of 16 cases), whereas we found a rate of 0% (none of 24 cases). The study by Chapman et al. appears to be incomplete compared with our study in many respects. Chapman et al. failed to state how they measured the tumors in their study (i.e., macroscopically vs. microscopically), and if only the invasive component was measured. In a recent study published in Cancer, Abner et al.3 found a discrepancy between microscopic tumor size and macroscopic tumor size in patients with T1 breast carcinomas, with the macroscopic tumor size being smaller than the microscopic size in 31% of patients, larger in 47% of patients, and equal in only 22% of patients. Furthermore, they found that microscopic invasive tumor size, as measured by us in our study was a better predictor of 10-year freedom from distant recurrence than macroscopic tumor size. They went on to recommend that the microscopic size of the invasive component of T1 breast carcinomas be reported routinely. Chapman et al.2 stated in the discussion from their original series on the assessment of tumor size in multifocal primary breast carcinoma that they made no attempt to determine the amount of invasive disease and assumed solid spherical tumor foci to determine surface area and volume. Furthermore, they attempted to support their high rate of lymph node positivity by quoting articles in the literature,4 which also failed to provide a standardized means of measuring the tumors. They went on to conduct a statistical analysis of the compiled data from the literature, essentially comparing apples and oranges, because these articles did not have a standardized means of measuring tumor size. Chapman et al. also promoted a novel technique, 3-dimensional longitudinal screening, for measuring tumor size described in an “in press” article that currently is shielded from peer scrutiny. Even if a radiologic modality were the accepted method for sizing infiltrating breast carcinomas, sizing infiltrating lobular carcinomas may be virtually impossible because infiltrating lobular carcinomas are difficult to even detect by mammography.5 Their tendency to be of low opacity and devoid of suspicious calcifications may account for the high false-negative rate (19%) reported on initial interpretation of mammograms.5 This brings us to the second major criticism of the study by Chapman et al. They did not make any mention of the histologic types of tumors in their study or tumor grade. In addition to tumor size and lymph node status, histologic typing and grading of breast carcinomas have outperformed other prognostic indicators.6-8 Our study found that the T1b tumors demonstrating lymph node metastases were of higher nuclear grade than T1b tumors that did not demonstrate lymph node metastases. Perhaps the tumors demonstrating metastases in the study by Chapman et al. also demonstrated unfavorable histologic features. In addition, Chapman et al. made no mention of the presence or extent of intraductal (in situ) carcinoma in their cases. They may not only have mistakenly measured extensive areas of intraductal carcinoma macroscopically or by radiologic means as invasive, but they also may have failed to consider the possibility that in a background of extensive intraductal carcinoma, additional foci of invasion may have accounted for the lymph node metastases. Finally, Chapman et al. failed to discuss how their lymph nodes were handled, which may have affected the rate of metastases detected. How many lymph nodes were examined per case? How many sections of each lymph node were examined? Were immunohistochemical stains applied to the lymph node sections to detect occult metastases? The same dilemma applies to those articles in the literature4 quoted by Chapman et al., many of which failed to provide standardized methods for handling lymph nodes. The continued use of sentinel lymph node biopsy may entirely eliminate the controversy regarding whether patients with small invasive breast carcinomas should undergo axillary lymph node dissections. In the meantime, larger prospective studies using standardized parameters are necessary to better evaluate tumors measuring ≤0.5 cm to assess metastatic potential. Enma Saiz M.D.*, Rebecca Toonkel , Robert J. Poppiti Jr. M.D. , * Department of Cytopathology, M.D. Anderson Cancer Center, Houston, Texas, The Arkadi M. Rywlin M.D. Department, of Pathology and Laboratory Medicine, Mount Sinai Medical Center, Miami Beach, Florida