ESTRO 2022 - Abstract Book

S741

Abstract book

ESTRO 2022

The primary endpoint was the radiation symptom severity score (MDASI-RSS) at 2y, a mean composite score of 9 MDASI-HN symptoms items (pain, fatigue, dry mouth, mucus in mouth/throat, difficulty swallowing/chewing, choking/coughing, taste, mouth/throat sores, teeth/gums). Mean MDASI-RSS, symptom severity (MDASI-SS), symptom interference (MDASI-SI) and selected single item scores were also compared at acute- (1 week [1w] post RT) and late time points (1y/2y) by laterality. FACT-H&N and HADS mean scores were also compared. Results There were 74 patients eligible for analysis (26 URT, 48 BRT). Median follow up was 3.7y (1.8-5.2y). Sociodemographic, staging and treatment variables were balanced; however larger primary GTVs (mean URT 7.2cc vs BRT 11.0cc, p =0.013) but not nodal GTVs (17.4 cc vs 20.8cc, p =0.17) were observed in the BRT group. Failure-free survival (HR=1.5, 95%CI:0.3-6.7) and time to locoregional failure (HR 5.8, 95%CI:0.6-55.8) were not statistically different between the two groups. Four regional failures were reported (3 URT 1 BRT), including 1 isolated contralateral regional failure in the URT cohort. PRO compliance was high (1y >90%; 2y >80%). The mean MDASI-RSS score ( Figure 1 ) at 2y was URT 1.1 vs BRT 1.3 (estimated difference [ED ] 0.1 [95% CI: -0.7-0.9], p =0.75). There were no significant differences in acute or late MDASI-RSS, MDASI- SS, or MDASI-SI scores, with BRT patients only reporting worse MDASI-SI 1w post RT (4.7 vs 5.6, ED 0.9 [0.0-1.9]). The only individual symptom scores that differed were worse fatigue (6.6 vs 5.4, ED 1.2 95%CI 0.2-2.3) and dry mouth (3.5 vs 2.0, ED 1.5, 95%CI 0.3-2.7) at 1w and 2y after RT, respectively in BRT patients. FACT-H&N and HADS were similar across the follow up period. Duration of enteral feeding was 11.2 weeks for BRT vs 6.7 weeks for URT, p =0.10).

Conclusion In this favourable risk HPV+ OPC cohort, treatment laterality resulted in fewer differences than had been anticipated, limited to worse acute fatigue and symptom interference and worse late dry mouth in BRT patients. In view of the small sample size, larger prospective studies will be helpful to better define any benefits of URT compared to BRT.

PD-0823 Adjuvant Radiotherapy for Node-negative Parotid Gland Cancer Patients Undergoing Curative Resection

J.B. PARK 1 , H. Wu 1 , J.H. Kim 1 , J.H. Lee 1 , S. Ahn 2 , E. Chung 2 , K. Eom 3 , W. Jeong 4 , T. Kwon 5 , S. Kim 6 , C.W. Wee 6

1 Seoul National University Hospital, Radiation Oncology, Seoul, Korea Republic of; 2 Seoul National University Hospital, Otorhinolaryngology-Head and Neck Surgery, Seoul, Korea Republic of; 3 Seoul National University Bundang Hospital, Radiation Oncology, Seongnam, Korea Republic of; 4 Seoul National University Bundang Hospital, Otorhinolaryngology-Head and Neck Surgery, Seongnam, Korea Republic of; 5 SMG-SNU Boramae Medical Center, Otorhinolaryngology-Head and Neck Surgery, Seoul, Korea Republic of; 6 SMG-SNU Boramae Medical Center, Radiation Oncology, Seoul, Korea Republic of Purpose or Objective To evaluate the role of adjuvant radiotherapy (ART) for node-negative parotid gland cancer patients undergoing curative resection based on adverse factors. Materials and Methods Two-hundred sixty-one pathologically confirmed parotid gland cancer patients who underwent curative surgery without regional or distant metastases between 2004 to 2019 were reviewed. Histology was classified according to the 2017 WHO classification unless tumor grade was otherwise described on pathology reports (e.g., low-grade salivary duct carcinoma). The benefit of ART regarding local control (LC), locoregional control (LRC), and disease-free survival (DFS) were evaluated.

Results