ESTRO 2020 Abstract book

S493 ESTRO 2020

Hypofractionated image guided re-irradiation for head and neck cancer is a feasible option with judicious use of advanced techniques in a carefully selected patient population who cannot undergo surgical excision for the recurrent disease PO-0828 Molecular Dynamics of Ebstein Barr Virus in Nasopharyngeal Carcinoma from a Non-Endemic area. M. Rafi 1 , R. Ganapathy 1 , R. Ravikumar 1 , C. Kainickal Thomas 1 , K. Sankarareddiar 2 , P. Sara George 3 , R. Kunnambath 1 1 Regional Cancer Centre, Radiation Oncology, Trivandrum, India ; 2 Regional Cancer Centre, Cancer Research, Trivandrum, India ; 3 Regional Cancer Centre, Biostatistics and Epidemiology, Trivandrum, India Purpose or Objective Nasopharyngeal Cancers(NPC) are relatively rare cancers worldwide but highly endemic in certain countries. It shows a consistent association with Epstein Barr Virus(EBV) which has been extensively studied in endemic areas. But there are only limited studies addressing this issue in non- endemic countries. OBJECTIVES To assess the prevalence of EBV in NPC in Indian population and to evaluate the correlation between EBV antibodies and pre treatment EBV DNA titres, to evaluate changes in viral load after radical treatment, relation between treatment response and post treatment EBV DNA titre. Material and Methods Thirty five patients with biopsy proven , non metastatic NPC registered at a tertiary Cancer Centre between Feb 2016 and June 2017 were included in the study. An informed consent was obtained for all patients. All patients underwent staging workup as per AJCC 7th edition and received radical chemoradiation with or without neoadjuvant chemotherapy. Radiotherapy was delivered using IMRT Rapid Arc technique using a SIB dose scheduling of 66Gy, 60Gy and 54Gy in 30 fractions each to high risk, intermediate risk and low risk planning target volumes respectively. Cisplatin at a dose of 80mg/m2 was given every three weeks along with radiotherapy in patients with no contraindications for the same. Others were given Carboplatin every three weeks. Blood samples were collected for each patient prior to treatment and at completion for assessing the EBV DNA titres as well as antibody assay ( EBV VCA IgM, EBV VCA/EA IgG and EBV EBNA IgG.) EBV DNA titres were estimated using qRT PCR technique and antibody titre using enzyme immune assay method. Patients were followed up as per the institutional protocol. Results EBV DNA was detected and quantified by qRT PCR in 33 patients (94.3%). There was no correlation between pre- treatment EBV DNA and antibody titres. The study could find a significant association between pre-treatment EBV DNA titre and composite stage of patients (p=0.030). A lower post treatment EBV DNA titre was associated with disease free status at 6 and 12 months of treatment completion.There was significant association between change in DNA titre and patients who had no evidence of disease on last follow up (p=0.020). Conclusion Pretreatment DNA titres correlates with stage/ tumor load of the patients. Post treatment titres as well as the change in titres had significant association with the outcome of the patient. However trials including larger number of patients and healthy controls with longer follow up is needed to reach at a definite conclusion regarding the use of EBV DNA as a potential biomarker in NPC.

PO-0827 Hypofractionated image guided re-irradiation in head - neck cancers; an Indian experience K. Talapatra 1 , P. Chadha 2 , M. Deshpande 3 , R. Mistry 3 , R. Vadgaonkar 2 , V. Mhatre 2 , S. Pilakkal 4 , S. Goyle 5 , S. Limaye 5 , I. Shaikh 6 , S. Badhwar 7 1 Kokilaben Dhirubhai Ambani Hospital and Medical Research Institute, Radiation Oncology -, Mumbai, India ; 2 Kokilaben Dhirubhai Ambani Hospital and Medical Research Institute, Radiation Oncology, Mumbai, India ; 3 Kokilaben Dhirubhai Ambani Hospital and Medical Research Institute, Surgical Oncology, Mumbai, India ; 4 Kokilaben Dhirubhai Ambani Hospital and Medical Research Institute-, Radiation Oncology, Mumbai, India ; 5 Kokilaben Dhirubhai Ambani Hospital and Medical Research Institute, Medical Oncology, Mumbai, India ; 6 Kokilaben Dhirubhai Ambani Hospital and Medical Research Institute, Medical Onocology, Mumbai, India ; 7 Kokilaben Dhirubhai Ambani Hospital and Medical Research Institute, Otorhinolaryngology, Mumbai, India Purpose or Objective To assess the feasibility and tolerance of two different schedules of hypo fractionated image guided radiotherapy (IGRT) in recurrent head and neck cancer. Material and Methods Thiteen consecutive patients presenting for re-irradiation between September 2016 and January 2019 were studied. All patients underwent standard clinico- radiological re-staging prior to re-irradiation and non- metastatic patients were considered for hypo-fractionated re-irradiation with a radical intent. Sites selection were such that either the surgeon had refused surgery or surgery would have been functionally were morbid. The common sites were Soft palate , pharyngeal wall , floor of mouth and fixed node . Four patients received concurrent cisplatin and two patient received concurrent nimotuzumab. Rest of the patients were refused concurrent chemotherapy by medical oncologist due to performance score or no concurrent chemotherapy was given in the 4 Gy / fraction schedule .Concurrent chemotherapy was given only in the 2.5 Gy per fraction schedule . Treatment decision was taken after a thorough discussion regarding available treatment options, expected outcomes and potential morbidities with patient. Patients were treated with either 48 Gy in 12 fractions ( 5 patients ) or 55Gy in 22 fractions ( 8 patients ). Re-irradiation dose and OAR constraints were tailored on individual basis considering previous available radiotherapy (RT) details, radiological data, toxicity and expected benefits . No prophylactic nodal irradiation was done. Results Median age of studied population was 64 years (range: 42 to 78 years). Twleven patients were men and one was woman. Mean interval between initial RT and re- irradiation was 3.3 years (range: 377 days to 3586 days). Mean PTV volumes was 107cc (range: 11.9cc to 343cc). Median Dmax to spinal cord was 21.73Gy. Concurrent chemotherapy ( cisplatin ) was administered in 4 (30.7%) patients and 2 (15.3%) received concurrent biotherapy with Nimotuzumab. Most common acute side effects was mucositis and grade 3 mucositis seen in 4 patients(30.7%). Other major toxicities were grade 3 dermatitis in 3 patients (23%). Feeding tube for nutritional support required in radiation for 9 (69.2 %)patients and 2 (15.3%)patients required hospitalization for 3 and 4 days each for supportive care .Both patients were on concurrent cisplatin. Post RT 4 weeks follow up, none had grade 3 dermatits or fistula or feeding tube dependency. Only one patient had mucosal ulceration over soft palate. At 3 months follow up, he had persistent mucosal ulcer . At 6 months the same patient had a mucosal ulceration however improved as compared to the 3 month follow up Conclusion