Follow-Up

Follow-up included prospective clinical examination and CT scans every 3 months during the first two years post-SBRT and every 6 months afterward. Follow-up PET scans were required only in cases of progressive soft tissue abnormalities observed on CT. Efficacy was assessed with the Response Evaluation Criteria in Solid Tumors (RECIST) (29). A complete response was defined as the disappearance of the target lesion, a partial response as a decrease of at least 30% of the tumor’s longest diameter and a progressive disease as an increase of at least 20% of the longest diameter. LC was defined as the absence of local failure. Local failure was characterized as the combination of a RECIST progressive disease and evidence of tumor viability as shown by biopsy or SUV_max in 18F-FDG PET above the pre-treatment SUV_max or above a value of 5 (30). Progression-free survival (PFS) was defined as the period of time from the end of SBRT to the date of local-regional failure, disseminated (visceral or lymph-node) recurrence or the patient’s death. OS was defined as the time between the end of SBRT and the patient’s death. Toxicity was evaluated with the National Cancer Institute’s Common Toxicity Criteria for Adverse Events version 4.0 (NCI-CTCAE).

Mean and median follow-up were respectively 27 and 25 months (range: 0.6–64). Only one patient was lost to follow-up after 10 months (Table 1).