Background The bone flare phenomenon, defined as an increase in bone lesion activity, is a kind of benign bone change in response to ongoing tumor treatment. The purpose of this study was to investigate the time, incidence, and clinical significance of bone flare in lung adenocarcinoma patients with bone metastases, as well as to observe the levels of serum alkaline phosphatase ALP and serum calcium Ca^2+ in patients with bone flare phenomenon.
Methods Fifty-seven patients with advanced lung adenocarcinoma who participated in the anti-tumor clinical trials from December 2017 to December 2019 in Linyi Cancer Hospital were included in the study. The CT (computed tomography, CT) images, serum ALP and Ca^2+ from all patients were analyzed retrospectively.
Results Among a total of 57 patients, 28 were male, and 29 were female. The median age was 62 years (33–75 years), and 30 of them had bone metastases at baseline. Forty-six EGFR negative patients received platinum-based dual-drug chemotherapy or bevacizumab or combined with PD-1 antibody inhibitors, and 11 EGFR positive patients received targeted EGFR inhibitors. The bone flare was detected in 7 out of 30 patients with bone metastases at baseline (5 patients in the combined chemotherapy group and two patients in the targeted treatment group). The incidence of bone flare was 23.33% (7 / 30). The median time was 45 days after treatment (from 41 days to 120 days), and most of them occurred in the early stages of the treatment.