Follow-up after primary treatment of soft tissue sarcoma of extremities: impact of frequency of follow-up imaging on disease-specific survival.

BACKGROUND AND OBJECTIVES: We explored the impact of frequency of surveillance imaging on disease-specific survival (DSS) in patients with extremity soft tissue sarcoma (STS). METHODS: Locoregional imaging (LRI) and chest imaging (CI) were used to detect local recurrence (LR) and distant metastasis (DM), respectively. Relapsing patients were retrospectively assigned to more frequent surveillance (MFS) or less frequent surveillance (LFS) groups, according to the median interval for each follow-up modality. Outcome measures included overall DSS (O-DSS), post-LR DSS, and post-DM DSS. RESULTS: We assigned 165 patients to three distinct risk groups according to tumor size (≤5 vs. >5 cm), depth (superficial- vs. deep-seated), grade (I vs. II or III), and surgical margin (≥10 vs. <10 mm). Data for 80 patients who relapsed were analyzed. Among 50 high-risk (with all four risk factors) relapsing patients, those in the MFS group for either LRI or CI had better O-DSS (LRI, median 44.07 vs. 27.43 months, P = 0.008; CI, median 43.60 vs. 36.93 months, P = 0.036), post-LR DSS (median 27.20 vs. 10.63 months, P = 0.028) and post-DM DSS (median 13.20 vs. 6.24 months, P = 0.031). CONCLUSION: More frequent follow-up were associated with improved survival in high-risk relapsing patients with extremity STS by providing greater opportunities for adequate reoperation.