Masaru Wakatsuki

Significance of PD-L1 expression in carbon-ion radiotherapy for uterine cervical adeno/adenosquamous carcinoma

Programmed cell death-ligand 1 (PD-L1) is expressed in tumor cells and has been shown to predict clinical outcomes of several types of malignancies. The aim of this study was to investigate the effects of carbon-ion (C-ion) beam irradiation on PD-L1 expression in human uterine cervical adeno/adenosquamous carcinoma (UCAA) cells and clinical samples and to identify the prognostic factors for outcomes after C-ion radiotherapy (CIRT). The effects of C-ion irradiation on PD-L1 expression in human UCAA and cervical squamous cell carcinoma cells were examined by flow cytometry. We examined PD-L1 expression in UCAA biopsy specimens from 33 patients before CIRT started (pre-CIRT) and after 12 Gy (relative biological effectiveness [RBE]) irradiation (post-12Gy-C) in 4 fractions of CIRT to investigate the correlation between PD-L1 status and clinical outcomes. The PD-L1 expression was upregulated by C-ion beam in a dose-dependent manner in HeLa and SiHa cells through phosphorylated Chk1. The overall frequencies of pre-CIRT and post-12Gy-C PD-L1 positivity were 45% (15/33) and 67% (22/33), respectively. The post-12Gy-C PD-L1 expression was significantly elevated compared to the pre-CIRT PD-L1 expression. There was no significant relationship between the pre-CIRT PD-L1 status and clinical outcomes, such as local control (LC), progression-free survival (PFS), and overall survival (OS). However, the post-12Gy-C PD-L1 expression had better correlation with PFS, but not with LC and OS. CIRT can induce PD-L1 expression in UCAA and we propose that PD-L1 expression after starting CIRT may become as a predictive prognostic marker in CIRT for UCAA.

Significance of concurrent use of weekly cisplatin in carbon‐ion radiotherapy for locally advanced adenocarcinoma of the uterine cervix: A propensity score‐matched analysis

AbstractBackgroundAlthough carbon‐ion radiotherapy (C‐ion RT) with concurrent chemotherapy (chemo‐C‐ion RT) is a promising treatment for adenocarcinoma (AC) of the uterine cervix, its long‐term efficacy remains unclear. We evaluated the long‐term significance of concurrent weekly cisplatin and C‐ion RT for locally advanced AC of the uterine cervix.MethodsWe performed a pooled analysis of patients with stage IIB–IVA AC of the uterine cervix who underwent C‐ion RT alone or chemo‐C‐ion RT between September 2007 and December 2018 at our institution. Patients received 74.4 Gy (relative biological effectiveness) with or without cisplatin (40 mg/m2 per week for up to 5 weeks), underwent no prior pelvic RT or systemic therapy, and had a performance status of 0‐2. Propensity score matching was based on the year of diagnosis, regional lymph node metastasis, and stage.ResultsThe matched cohort contained 26 patients who underwent C‐ion RT and 26 who underwent chemo‐C‐ion RT. The median age and follow‐up period were 57 (range, 28‐79) years and 34 (range, 2‐126) months, respectively. The 5‐year overall survival rate was significantly better in the chemo‐C‐ion RT group (72%) than in the C‐ion RT group (46%; P = .041). The 5‐year distant metastatic‐free rate was also significantly better in the chemo‐C‐ion RT group (66%) than in the C‐ion RT group (41%; P = .048). The incidence of grade ≥ 3 late toxicities was comparable between the two groups.ConclusionsChemo‐C‐ion RT for locally advanced AC of the uterine cervix is associated with a long‐term survival benefit.