Higher Anti-Tumor Efficacy of the Dual HER3-EGFR Antibody MEHD7945a Combined with Ionizing Irradiation in Cervical Cancer Cells.

PURPOSE: The outcome of locally advanced cervical cancer (LACC) is dismal. Biomarkers are needed to individualize treatments and to improve patient outcomes. Here, we investigated whether coexpression of epidermal growth factor receptor (EGFR) and human epidermal growth factor receptor 3 (HER3) could be an outcome prognostic biomarker, and whether targeting both EGFR and HER3 with a dual antibody (MEHD7945A) enhanced ionizing radiation (IR) efficacy. METHODS AND MATERIALS: Expression of EGFR and HER3 was evaluated by immunohistochemistry in cancer biopsies (n = 72 patients with LACC). The antitumor effects of the MEHD7945A and IR combotherapy were assessed in 2 EGFR- and HER3-positive cervical cancer cell lines (A431 and CaSki) and in A431 cell xenografts. The mechanisms involved in tumor cell radiosensitization were also studied. The interaction of MEHD7945A, IR, and cisplatin was evaluated using dose-response matrix data. RESULTS: EGFR and HER3 were coexpressed in only in 7 of the 22 biopsies of FIGO IVB cervix cancer. The median overall survival was 14.6 months and 23.1 months in patients with FIGO IVB tumors that coexpressed or did not coexpress EGFR and HER3, respectively. In mice xenografted with A431 (squamous cell carcinoma) cells, MEHD7945A significantly increased IR response by reducing tumor growth and increasing cleaved caspase-3 expression. In A431 and CaSki cells, the combotherapy increased DNA damage and cell death, particularly immunogenic cell death, and decreased survival by inhibiting the MAPK and AKT pathways. An additive effect was observed when IR, MEHD7945A, and cisplatin were combined. CONCLUSIONS: Targeting EGFR and HER3 with a specific dual antibody enhanced IR efficacy. These preliminary results and the prognostic value of EGFR and HER3 coexpression should be confirmed in a larger sample.

Long-term follow-up experience in anal canal cancer treated with Intensity-Modulated Radiation Therapy: Clinical outcomes, patterns of relapse and predictors of failure.

BACKGROUND AND PURPOSE: To assess the long-term outcomes of patients with squamous cell carcinoma of the anal canal (SCCAC) treated with Intensity-Modulated Radiation Therapy (IMRT). MATERIAL AND METHODS: From 2007 to 2015, 193 patients were treated by IMRT for SCCAC. Radiotherapy delivered 45 Gy in 1.8 Gy daily-fractions to the primary tumor and elective nodal areas, immediately followed by a boost of 14.4-20 Gy to the primary tumor and involved nodes. Concurrent chemotherapy with 5-FU-mitomycin (MMC) or cisplatin was added for locally advanced tumors. Survivals were estimated by Kaplan-Meier method. Locoregional (LR) relapses were precisely assessed. Prognostic factors were evaluated by uni- and multivariate analyses. Late toxicity was scored according to the Common Toxicity Criteria for Adverse Events v4.0. RESULTS: Median follow-up was 70 months (range, 1-131). Forty-nine men (25%) and 144 women (75%) were analyzed. Median age was 62 years. Tumor stages were I, II, III and IV in 7%, 24%, 63% and 6% of cases, respectively. Chemotherapy was delivered in 167 patients (87%), mainly MMC (80%). Five-year OS, DFS, CFS and LR control rates were 74%, 68%, 66% and 85%, respectively. Forty-one patients (21%) had a relapse: 22 were LR, mostly in-field (68%). Predictors for LR failure were exclusive radiotherapy, chemotherapy lacking MMC and treatment breaks >3 days. Overall late toxicity ≥grade 2 occurred in 43% of patients, with 24% grade 3 and one case of grade 4 (hematuria). CONCLUSION: CRT with IMRT assures excellent local control in locally advanced SCCAC with manageable long-term toxicity. Multicentric prospective trials are required to reinforce those results.

Risk-adapted stereotactic ablative radiotherapy for central and ultra-central lung tumours.

BACKGROUND: SABR is a widely accepted treatment for early-stage lung cancer but there are safety concerns for central and ultra-central tumours. Herein we report our experience using risk-adapted fractionation (prescribed doses: 40-60 Gy in 3-8 fractions) with prioritization of dose to organs at risk. METHODS: Patient declining or unsuitable for surgery with primitive or recurrent lung cancer were included. Tumours inside a 2 cm area around proximal bronchial tree (PBT) were classified as central while tumours with PTV overlapping PBT, oesophagus, great vessels and pericardial pleura were classified as ultra-central. We assessed overall survival (OS), disease-free survival (DFS), local control (LC) and toxicities. RESULTS: From 2009 to 2016, 137 patients were treated (median age: 75 years), with 60 central and 77 ultra-central tumours. Median follow-up was 36 months. Median tumour size, GTV and PTV were 2.5 cm (0.9-7), 7.8 cm3 (0.7-94.2) and 30.6 cm3 (6.5-274.3), respectively. For the whole population, median OS and DFS were 46 months and 33 months. One- and 2-years LC rates were 95% and 81%. Median OS between central and ultra-central tumours was statistically different with 57 vs 37 months (HR 0.48, p = 0.017), but LC was not different among them. We observed 4 Grade 3 and 6 Grade 5 toxicities (no grade 4). CONCLUSIONS: SABR for central and ultra-central tumours is associated with good OS, DFS and LC rates, with 7.3% grade 3-5 toxicities. Central tumours had a better prognosis in our cohort.

Central3D: A Computer Tool to Help Clinicians Differentiate Central and Peripheral Lung Tumors.

PURPOSE: We present a concise description of an in-house decision aid software called "Central3D" that allows a quick and robust lung tumor classification between central and peripheral as defined by the Radiation Therapy Oncology Group (RTOG) 0813. METHODS AND MATERIALS: Twenty cases of lung tumors were selected for this study and four radiation oncologists blindly classified them as peripheral versus central without assistance of our software. All discordant cases were reviewed using Central3D and prompt consensus was obtained. RESULTS: Many authors have stressed the importance of adopting risk adaptive fractionation schedule with lower biological equivalent dose when treating centrally-located high risks lesions. Central3D addresses the limitation of current treatment planning systems to represent image data in fixed planes and can help radiation oncologists to fully characterize these pulmonary lesions.

SBRT planning for liver metastases: A focus on immobilization, motion management and planning imaging techniques.

AIM: To evaluate the different techniques used for liver metastases Stereotactic Body Radiation Therapy (SBRT) planning. We especially focused on immobilization devices, motion management and imaging used for contouring. BACKGROUND: Although some guidelines exist, there is no consensus regarding the minimal requirements for liver SBRT treatments. MATERIALS AND METHODS: We reviewed the main liver metastases SBRT publications and guidelines; and compared the techniques used for immobilization, motion management, margins and imaging. RESULTS: There is a wide variety of techniques used for immobilization, motion management and planning imaging. CONCLUSIONS: We provide a subjective critical analysis of minimal requirements and ideal technique for liver SBRT planning.