Postoperative CT surveillance in the evaluation of local recurrence after sub-lobar resection of neoplastic lesions of the lung

Objective: As indications for sub-lobar resections increase, it will become more important to identify risk factors for postsurgical recurrence. We investigated retrospectively the association between local recurrence after sublobar resection of neoplastic lung lesions and pre- and post-operative CT imaging and pathologic features. Materials and methods: We reviewed retrospectively neoplastic lung lesions with postoperative chest CT surveillance of sub-lobar resections in 2006-2016. We defined "suspicious" findings as nodularity >= 3 mm or soft tissue thickening >= 4 mm along the suture line and/or progression and explored their association with local recurrence. Primary lung cancer stage, tumoral invasion of lymphatics, visceral pleura or large vessels, bronchial and vascular margin distance were also assessed. Results: Our study group included 45 cases of sub-lobar resection took for either primary (n = 37) or metastatic (n = 8) lung tumors. Local recurrence was observed in 16 of those patients. New nodularity >= 3 mm or soft tissue thickening >= 4 mm along the suture line on surveillance CT was significantly associated with local recurrence (p = 0.037). Additionally, solid nodule (p = 0.005), age at surgery <= 60 years (p = 0.006), two or more sites of invasion (p < 0.0001) and poor histologic differentiation (p = 0.0001) were also significantly associated with local tumor recurrence. Of 16 patients with surveillance post-surgical PET-CT, 15 had elevated FDG uptake. Conclusion: The postoperative changes along the suture line should follow a predictable time course demonstrating a pattern of stability, thinning or resolution on CT surveillance. New or increasing postoperative nodularity >= 3 mm or soft tissue thickening >= 4 mm along the suture line requires close diagnostic work-up. Surgical pathology characteristics added prognostic value on postoperative recurrence surveillance.