Focal ground-glass opacities in non-small cell lung carcinoma resection patients

Purpose: To retrospectively determine the frequency, natural progression, radiographic characteristics, and primary cancer cell type of focal ground-glass opacities (GGOs) identified on serial radiographic examinations in patients with prior non-small cell lung carcinoma (NSCLC) resection. Methods: One thousand three hundred and seventy-nine CT examinations in 154 patients with NSCLC resection between 1997 and 2008 were reviewed by two radiologists to determine the frequency of postoperative focal GGOs. Percentages, imaging characteristics and primary cancer cell types of GGOs that persisted, resolved, or resected were recorded. For persistent GGOs, growth rate was determined. Results: Of 154 patients, 67 (44%) developed 174 GGO during a mean follow-up of 2.7 years (standard deviation 2.23 years, range 1 month to 10 years). Of these 174 opacities, 110 (63%) spontaneously resolved within 6 months. Of the remaining 64 lesions, 5 (3%) were resected and 59 (34%) persisted and demonstrated indolent growth with a median annual growth rate of 2.02 mm. Of the 59 persistent GGOs, 41 (69%) were nodularly shaped, 58 (95%) indistinctly marginated, 17 (29%) with pseudocavitation and 25 (42%) contained solid elements. Adenocarcinoma was the original resected cancer in more than half of these lesions (37 of 59, 63%). Conclusions: In individuals who have undergone NSCLC resection, approximately 44% will develop focal GGO on follow-up CT examination. A majority of these GGOs will spontaneously resolve by 6 months after initial identification. As most persistent GGOs are indolent, we propose an initial 6-month interval reimaging once postoperative GGOs are detected followed by subsequent annual surveillance.