We read with great interest the article by Dhopeshwarkar et al on screen-detected lung cancer. In their discussion, the authors stated that not a small percentage of screen-detected lung cancers on computed tomography (CT) were indolent and that there may be so-called overdiagnosis in mass screening using chest CT, which was suggested by Lindell et al . We agree with this estimation. In their article, however, Dhopeshwarkar et al reported that only 8.3% of lung cancers had doubling times > 400 days in a screening program using chest CT. This very low rate is almost the same as in the Mayo Lung Project and in a study at the Memorial Sloan-Kettering Cancer Center, evaluated using chest radiography . Also, this low rate was apparently different from those in studies by Hasegawa et al and Sone et al , evaluated using chest CT, as in the study by Dhopeshwarkar et al. We are very interested in these differences in rates. We would like to hear from the authors regarding why these differences were observed and the reason for the difference among them, although these recent studies were evaluated using chest CT.
References
1. Dhopeshwarkar M.R., Roberts H.C., Paul N.S., et. al.: Screen-detected lung cancer: a retrospective analysis of CT appearance. Acad Radiol 2011; 18: pp. 1270-1276.
2. Lindell R.M., Hartman T.E., Swensen S.J., et. al.: Five-year lung cancer screening experience: CT appearance, growth rate, location, and histologic features of 61 lung cancers. Radiology 2007; 242: pp. 555-562.
3. Yankelevitz D.F., Kostis W.J., Henschke C.I., et. al.: Overdiagnosis in chest radiographic screening for lung carcinoma: frequency. Cancer 2003; 97: pp. 1271-1275.
4. Hasegawa M., Sone S., Takashima S., et. al.: Growth rate of small lung cancers detected on mass CT screening. Br J Radiol 2000; 73: pp. 1252-1259.
5. Sone S., Matsumoto T., Honda T., et. al.: HRCT features of small peripheral lung carcinomas detected in a low-dose CT screening program. Acad Radiol 2010; 17: pp. 75-83.