Radioembolization-induced Tumor Calcifications as a Surrogate Marker of Tumor Response in Patients With Hepatocellular Carcinoma

Background/Aim: Tumoral calcification after chemotherapy or radiation therapy has been reported in various cancer patients, but not after radioembolization. The purpose of this study was to evaluate the prognostic value of radioembolization-induced tumor calcification of hepatocellular carcinoma (HCC) treated by radioembolization. Patients and Methods: This retrospective study comprised patients with single nodular HCC who underwent yttrium-90 radioembolization between November 2015 and April 2019. The presence of tumoral calcification was visually assessed on a follow-up computed tomography (CT) scan. Results: Fifty- five patients (64.8 +/- 11.8 years, 43 men) were evaluated. Tumoral calcification was present in 21 (38.2%) of 55 patients in the one-month CT scan (calcification group). The complete response rate for the primary index tumor was 72.7% (40 of 55) in the total study population, and 100% (21 of 21) in the calcification group, respectively. The calcification group had a longer local progression-free survival rate than the non- calcification group (p=0.017). Conclusion: Radioembolization- induced tumoral calcification is relatively common and can be used as an early surrogate marker of complete response.