The difference of auxiliary examination parameters between margin recurrence and granuloma on enhanced computed tomography after sublobar resection

BACKGROUND: Imaging examinations following sublobar resection of lung cancer often find thickened neoplasms around the resection margin. Identifying whether the neoplasms are postoperative recurrence or margin granulomas is vitally important. However, the identification mainly depends on the empirical judgment of the imaging department or clinicians in each clinical center at present, and there are few relevant studies, so it is hard to formulate a relatively unified standard. Therefore, we collected data from patients with thickened neoplasms around the resection margin after sublobar resection and sought to discover how to differentiate granulomas from tumor recurrence. METHODS: We examined the clinical records of 15 patients with neoplasms around the margins which identified as malignant in auxiliary examination reports, and received second surgery after first sublobar resection. We collected their postoperative pathology and auxiliary examination parameters. The univariate predictors helpful in distinguishing between recurrence and granuloma were analyzed as a diagnostic test. RESULTS: Of the 15 patients with neoplasms around the resection margin, six were diagnosed with benign granulomas, and nine were diagnosed with primary lung cancer recurrence. The results revealed that age, gender, specific surgical method, maximum standardized fluorodeoxyglucose uptake value (SUVmax), and follow-up time were not significantly different, but there were significant differences in enhanced computed tomography (CT) values in several analyses, which calculated by the hospital imaging system. The maximum CT values of the tumor recurrence and granuloma were 104.9±8.051 and 130.3±7.017 (P=0.045), the minimum CT values (15.67±5.113 vs. −17.17±4.826, P=0.0007) and in the floating range CT values (148.00±5.471 vs. 88.11±7.671, P<0.0001), respectively. CONCLUSIONS: Differentiating between tumor recurrence and granulomas after sublobar resection remains difficult. However, examining the differences in enhanced CT allows the clinician to make an informed diagnosis that aids further investigation and treatment.