ESTRO 37 Abstract book

S828

ESTRO 37

Results The median age at presentation is 52 years. Around 58.3% of the patients had FIGO stage IIB followed by Stage IIIB (30.6%). 7 patients (19.4%) had hemoglobin level <10mg/dl at baseline before starting radiotherapy. Out of the 36 patients studied, the proportion of patients developing ≥ grade 2 acute toxicities (CTCAE grading) anemia, leucopenia, neutropenia and thrombocytopenia were 25%, 8.3%, 5.6% and 0% respectively. The proportion of patients developing ≥ grade 2 acute dermatitis, vomiting, diarrhea, proctitis and cystitis were 5.6%, 2.8%, 22.2%, 2.8% and 0% respectively. Notably, there were no grade 3 or 4 acute reactions in any of the toxicities studied except grade 3 neutropenia in 1 patient. Most commonly observed toxicity in the first week was vomiting while dermatitis was the most common one in the second, third, fourth and fifth week of EBRT. Highest grade of toxicity noted during chemo-radiation was grade 3 neutropenia, seen in one patient at the fifth week of external beam radiotherapy. The toxicities that appeared right from the first week were vomiting and diarrhea. Many patients developed diarrhea (33.3%) and proctitis (22.2%) only in the last two weeks of EBRT while more cystitis (30.5%) was noted at the end of EBRT and during brachytherapy. Conclusion The present study suggests that concurrent chemo- radiation using VMAT has an excellent acute toxicity profile in the treatment of carcinoma cervix with no grade 3 gastrointestinal, urinary and dermatologic reactions. EP-1529 Dosimetric parameters in anatomical sites correlate with blood values in cervical cancer patients D. Hallqvist 1 , C. Kormann 1 , M. Oechsner 1 , M.N. Duma 1 , S. Pigorsch 1 , S.E. Combs 1 , D. Habermehl 1 1 Klinikum rechts der Isar, Radiation oncology, Munich, Germany Purpose or Objective For women with locoregionally advanced cervical cancer FIGO stage IIA-IVA, the current standard of care treatment is a radiochemotherapy (RCT) combined with a sequential brachytherapy. The success of radiation therapy (RT) is e.g. dependent on stage, tumor volume, delivered radiation dose, treatment duration and hemoglobin levels. The bone marrow (BM) precursor cells are radiosensitive and a relationship between BM dose- volume histograms and acute hematological toxicity is known. Thus BM sparing radiation therapy could improve hemoglobin levels and overall survival (OS). The treatment response under radiation therapy is variable and the impact on the outcome still unclear. Therefore in this study the gross tumor volume (GTV) before and during radiation therapy was investigated and its impact on overall survival. Material and Methods The radiation treatment plans of 31 patients (age 25-78 years) with FIGO stage IIB – IVB cervical cancer, that were treated between 2010 and 2016 with definitive RCT at our department were retrospectively explored. The pelvic bones (PB) and the right and left femoral head (FH) were contoured and dose-volume histograms were correlated with white blood cells (WBC), hemoglobin levels and platelets. Additionally the GTV of the cervical tumor was contoured on T2 MRI images before (GTV 1) and during radiation therapy (GTV 2). The difference of both GTVs (deltaGTV) was defined and correlated with OS.

evaluated immediately after 30 Gy concurrent treatment. Acute intestinal toxicity was assessed using the gut colony assay, while sub-acute (30 days post-RT) and late (90 days post-RT) intestinal toxicity were assessed histologically using a previously validated intestinal radiation injury scoring system. Results The combination of RTCT (30 Gy) and Plerixafor produced substantial tumor growth delay compared to RTCT alone regardless of sequencing. However, continuous and adjuvant Plerixafor were associated with significantly longer growth delay than concurrent Plerixafor. With a higher RT dose of 50 Gy to more closely approximate the clinical environment, tumor cure was achieved with RTCT + concurrent Plerixafor. Tumor biomarker assessment at the end of RT (30 Gy) or RTCT alone showed higher CXCL12 and pCXR4 levels and a higher concentration of tumor infiltrating, Ly6G-expressing myeloid derived suppressor cells (MDSCs), consistent with treatment- induced pathway upregulation and MDSC chemotaxis. The addition of Plerixafor abrogated both of these effects. Plerixafor was also associated with reductions in pAKT and pERK, in keeping with direct effects on downstream intracellular signalling pathways. In the acute intestinal toxicity study, a higher level of surviving crypt cells was observed with the addition of Plerixafor to RT or RTCT compared to RT or RTCT alone, suggesting a protective effect. Sub-acute intestinal toxicity was similar between treated arms, but late intestinal toxicity was lower in the RTCT + Plerixafor arm compared to the RT and RTCT arms, again suggesting a protective effect of Plerixafor. Conclusions Adding Plerixafor to RTCT enhances the response of cervical cancer PDX models, blunts treatment-induced upregulation of the CXCL12/CXCR4 pathway and might have protective effect on the intestinal tract. Translation of these findings to phase I/II clinical trials is promising in cervical cancer. Lecavalier-Barsoum and Chaudary contributed equally EP-1528 Evolution of acute toxicities in Volumetric Modulated Arc Therapy of uterine cervix cancer K. SRI HARSHA 1 , S. Saikumar 1 , V. Niranjan 1 , K. Ajay S 1 , P. Kannan 1 , S. Mourougan 1 , P. Jagadesan 1 1 JIPMER, Department of Radiation Oncology, Puducherry, India Purpose or Objective To evaluate the occurrence of acute gastrointestinal, urinary, dermatologic and hematologic toxicities in patients of carcinoma cervix treated with radical concurrent chemo-radiotherapy (CCRT) using Volumetric Modulated Arc Therapy (VMAT). Material and Methods Thirty-six patients of carcinoma cervix FIGO stage IB2-IVA have been prospectively studied during the course of their treatment with radical concurrent chemo-radiation using VMAT. The patients were treated to a total dose of 50.4 Gy in 28 fractions along with once weekly Cisplatin (40 mg/sq.m) followed by 3 sessions of brachytherapy, delivered one week apart to a dose of 8Gy to point A each. The gastrointestinal, urinary, dermatologic and hematologic toxicities were evaluated weekly during the external beam irradiation (EBRT) and also at the end of brachytherapy schedule. The toxicities were graded using Common Terminology Criteria for Adverse Effects version 4(CTCAE v4). The data analysis was done by SPSS version 20.