NEW YORKComputed tomography (CT) screening for lung cancer has revealed
subtypes of nodules whose natural histories are being assessed in long-term
follow-up, according to Claudia I. Henschke, PhD, MD, director, Division of
Chest Imaging, and professor of radiology, Weill Medical College, Cornell
Classification is based on the extent to which the parenchyma within the
nodule is obscured. "If it’s totally obscured, it’s solid. If it’s partially
obscured, it’s part-solid, and otherwise, it’s nonsolid," she said at the 7th
International Conference on Screening for Lung Cancer.
The first 1,000 baseline screens at her institution and New York
University identified 233 nodules, she said. Of these 189 were solid, 16
part-solid, and 28 nonsolid. Among the 136 nodules that were 1 to 5 mm in
size, 127 were solid, 2 part solid, and 7 nonsolid.
Cancer was detected in 27 cases, or 12% of the 233 nodules. The
distribution included 14 solid nodules, 8 part-solid, and 5 nonsolid. No new
cancers have been discovered in solid nodules in follow-up since the baseline
screening in 1998, Dr. Henschke reported.
With solid nodules, she said, growth assessment within 3 months proved
diagnostically reliable. "But that’s not quite the same for the part-solid
and the non-solid lesions," she said. Five additional malignancies have been
diagnosed in these subtypes, two in part-solid nodules and three in nonsolid.
In one patient, a high-resolution scan of a 15-mm part-solid nodule
identified at baseline prompted recommendation of a biopsy of what was
considered a stage I cancer. The patient declined and went to other
institutions for other tests. "By the time there was clear evidence of
growth, it was 4 years later," Dr. Hen-schke reported, "and at that point the
tumor was stage IV." The cancer was identified as adenocarcinoma.
Another patient with a 10-mm part-solid nodule also initially refused to
have a biopsy but had one 2 years later. The stage IA adenocarcinoma was