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

Abstract

Background: 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.

Methods: 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.

Results: 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.

Conclusions: 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.

Figure 1.

Patient population flow diagram. FNCLCC, French Federation of Cancer Centers Sarcoma Group; STS, soft tissue sarcoma; USSC, US Sarcoma Collaborative.

Figure 2.

Kaplan-Meier curves of patients with pulmonary metastasis compared according to chest imaging modality. (A) Lung-specific recurrence-free survival, (B) overall survival, and (C) overall survival excluding patients with documented lung metastases. CXR, chest x-ray.