Stereotactic hypo-fractional radiotherapy of patients with lung cancer I-IIa clinical stage: the role of SUVmax assessment in 18F-FDG PET/CT for monitoring treatment outcomes
Material and methods: Since 2014, 33 patients with lung cancer of clinical stage I-IIa (cT1N0M0 - 12 patients, with T2N0M0 - 21 patients) have undergone SRT. Verification of tumor process was obtained in 30 patients. A third of patients (n = 10) had a history of metachronic primary-multiple tumors and 31 patients had peripheral lung cancer. The used variants of SRT fractionation were as followed: 10Gr x 5 fractions (n = 22) and 7Gr x 8 fractions (n = 11) - BED 100Gy. Results: With a median follow-up of 21 months (range 3-37 months), 4 patients (12 %) within the first year had a loco-regional and distant progression, of which two died. During the year one patient died from complications of treatment, one - from the progression of the second tumor. One- and two-year local control was 94 %. Overall and disease-free 2-year survival was 84 % (95 % CI, 70 - 99) and 83.2 % (95 % CI, 70.5 - 99), respectively. Single-factor analysis revealed a significant effect on the overall survival of the fractionation regimen (p = 0.04). The effect of the baseline SUVmax tended to be reliable (p = 0.07). Conclusions: In order to implement the principles of risk-adaptive radiation therapy it is necessary to consider the initial SUVmax of tumor as one of potential predictive and predicative markers of treatment effectiveness.