Lung Surveillance Strategy for High-Grade Soft Tissue Sarcomas: Chest X-Ray or CT Scan?

Abstract

Given the propensity for lung metastases, National Comprehensive Cancer Network guidelines recommend lung surveillance with either chest x-ray (CXR) or CT in high-grade soft tissue sarcoma. Considering survival, diagnostic sensitivity, and cost, the optimal modality is unknown. The US Sarcoma Collaborative database (2000 to 2016) was reviewed for patients who underwent resection of a primary high-grade soft tissue sarcoma. Primary end point was overall survival (OS). Cost analysis was performed. Among 909 patients, 83% had truncal/extremity and 17% had retroperitoneal tumors. Recurrence occurred in 48%, of which 54% were lung metastases. Lung surveillance was performed with CT in 80% and CXR in 20%. Both groups were clinically similar, although CT patients had more retroperitoneal tumors and recurrences. Regardless of modality, 85% to 90% of lung metastases were detected within the first 2 years with a similar re-intervention rate. When considering age, tumor size, location, margin status, and receipt of radiation, lung metastasis was independently associated with worse OS (hazard ratio 4.26; p < 0.01) and imaging modality was not (hazard ratio 1.01; p= 0.97). Chest x-ray patients did not have an inferior 5-year OS rate compared with CT (71% vs 60%; p < 0.01). When analyzing patients in whom no lung metastases were detected, both cohorts had a similar 5-year OS rate (73% vs 74%; p= 0.42), suggesting CXR was not missing clinically relevant lung nodules. When adhering to a guideline-specified protocol for 2018 projected 4,406 cases, surveillance with CXR for 5 years results in savings of $5 million to $8 million/year to the US healthcare system. In this large multicenter study, lung surveillance with CXR did not result in worse overall survival compared with CT. With considerable savings, a CXR-based protocol can optimize resource use for lung surveillance in high-grade soft tissue sarcoma; prospective trials are needed.