In regard to Giraud et al.: Evaluation of microscopic tumor extension in non-small-cell lung cancer for three-dimensional conformal radiotherapy planning. IJROBP 2000;48:1015–1024

To the Editor: I applaud Dr. Giraud and his colleagues’ efforts in working meticulously on such a large number of specimens. There are some differences in our findings on the same topic (Arch Pathol Lab Med 2001;125:1469–1472). We do have several questions regarding their methodology and findings: 1.They do conclude that surrounding inflammation is a common finding, especially in squamous-cell carcinoma (p. 1019, 1st paragraph). However, in Table 2, it is interesting that the mean radiologic size correlates so well with the histologic size, but is consistently smaller than the macroscopic size. If this is because the macroscopic size is influenced by surrounding inflammation, then their CT scanner must be so much more accurate than our CT scanner in differentiating tumor vs. surrounding inflammation! This, I think, results in the major difference in the conclusions of our and their findings. 2.Because of the comment that surrounding inflammation might interfere with finding cancer cells in that area, we wondered whether we missed some microscopic extension in the area of inflammation in our study. Our pathologist went back and did immunohistochemical staining on our slides and confirmed the absence of malignant cells in the region of surrounding inflammation in our patient population, and thus confirmed our findings. 3.We also wonder about their insufflation method. It is extremely difficult to assess numbers in micro-mm magnitude accurately in pathologic specimens, which require a lot of handling and preparations. Dr. Giraud qualified the insufflation method as good, moderate, and poor. Only the well-insufflated slides were studied eventually. Even in these well-insufflated slides, the microscopic extension measurement can vary significantly, depending on the amount of formalin injected and how close the insufflation is simulating the “real-life” situation when the lung is still in vivo. In response to Dr. ChanInternational Journal of Radiation Oncology, Biology, PhysicsVol. 53Issue 4Preview Full-Text PDF