ESTRO 2020 Abstract book

S486 ESTRO 2020

PO-0813 Total tumor volume as a prognostic factor in head and neck cancer patients. I. Bashir 1 , S. Sahu 1 , S. Pandita 1 , M. Kharbanda 1 , R. Sharma 1 , A. Bhatnagar 1 1 Batra Hospital and Medical Research Centre, Radiation Oncology, New Delhi, India Purpose or Objective To evaluate the prognostic value of total tumor volume (TTV) in patients of locally advanced head and neck cancer. Material and Methods This study included 155 patients of previously untreated locally advanced squamous cell carcinoma of larynx, oropharynx and hypopharynx. TTV was calculated from pretreatment contrast enhanced computed tomography images and was defined as the sum of primary tumor volume and nodal volume. Chi square test was used to compare categorical variables. The log rank test was used to compare survival rates. Receiver operating characteristic (ROC) analysis was applied with a 95% confidence interval to determine the area under the curve (AUC) of TTV. Survival curve was calculated using the Kaplan Meier method. Results The 155 eligible patients included 140 men and 15 women, with median age 61 years (range, 28–89 years). Of these patients, 80(51%) had oropharyngeal cancers, 45(29%) had laryngeal cancers and 30(19.4%) had hypopharyngeal cancers. 94 patients (60.7%) were classified as having advanced T3–4 stage tumors and 114(73.5%) as having N1– 3 tumors. A total of 77 patients(49.7%) had stage III while as 78 patients(50.3%) had stage IV disease. Median Primary tumor volume was 23.25ml(range, 1.1-235ml), median nodal volume was 3.5ml(range, 0-232ml), and median TTV was 35.10ml(range, 1.1-282.4ml). The median follow‐up period of survivors was 28 months(range, 02–80 months). Complete response (CR) was seen in 59(38.3%) patients; partial response (PR) in 19(12.2%) patients and progressive disease (PD) in 21(13.5.%) patients while 25(16.1%) patients died on treatment. 31(20%) patients who had a CR in the primary site had a late failure (local recurrence). Therefore, treatment failure in the form of recurrence, progressive disease and partial response was seen in 45% of the patient population. The 2-year OS, DFS rates of the entire cohort were 47% and 52% respectively. ROC curves were estimated to calculate the ideal total tumor volume cutoff point for OS and DFS. The ROC curve analyses yielded an optimal cutoff value for TTV of 21.7ml, with an area under the ROC curve of 0.59 (95% CI, P=0.013). Univariate analyses showed that only TTV was significant predictor of OS and DFS (P<0.05). TTV at the cutoff value of 21.7ml remained an independent predictor of OS and DFS (95% CI).

Fig. Kaplan Meier curves. The mean overall survival for TTV <21.7 and >21.7 was 56.59 months(48.65-64.54) and 38.85 months(32.56-45.15) (p value= 0.002) and the DFS for TTV < 21.7 and >21.7 was 50.52 months(40.63-60.40) and 34.72 months(27.82-41.6) (p value=0.007) respectively. Conclusion Radiologically determined TTV is a prognostic indicator of overall survival and disease-free survival in locally advanced laryngeal, oropharyngeal and hypopharyngeal cancers. Volume measurements, when added to the AJCC TNM staging system, may improve patient stratification and outcome predictions in these patients. The role of tumor volume as a separate staging system can be determined in larger prospective cohorts. PO-0814 Clinical feature and survival result of ascending,descending,mixed types of NPC in non- endemic area P. Zhang 1 , Y. Fan 1 , K. Xie 1 , L. Kang 1 , Q. Yang 1 , W. Guan 1 , A. Chen 1 , Q. Tang 1 1 Department of Radiation Oncology- Sichuan Cancer Hospital & Institute- Sichuan Cancer Center- School of Medicine-University of Electronic Science and Technology of China- Chengdu- China, Department of Radiation Oncology, chengdu, China Purpose or Objective To compare clinical characteristics and survival outcomes of patients with ascending type (type A), descending type (type D) and mixed type (type AD) in non-endemic area nasopharyngeal carcinoma(NPC) in the intensity- modulated radiotherapy era(IMRT). Material and Methods The cohort included 628 patients with type A, type D, and AD NPC from January 2009 to December 2014. Ascending NPC(type A) was defined as advanced local disease (stage: T3-4) and early-stage cervical lymph-node involvement (stage: N0-1); Advanced lymph-node metastases (stage: N2-3) but early -stage local disease (stage: T1-2) was classified as the descending type (type D); Mixed NPC (type AD) was classified as patients with mainly advanced local disease (stage T3-4) and advanced lymph node (stage : N2- 3). Propensity score matching(PSM) method was adopted to balance clinic factors and match patients. Kaplan-Meier methods and Cox proportional hazard models were used to evaluate the impact of different types on survival outcomes. Results Our patients were 145 patients with type A, 194 with type D, and 289 with type AD. But after PSM, there were only 130 people in each type.Compared with type A, patients with type AD show lower OS, PFS, and DMFS (P < 0.05 for all). Among patients with type AD,there may be increased likelihood compared to type D tumors(P < 0.05 for all) in local recurrence, disease progression and death.Multivariate analysis suggested that N stage was an independent prognostic factor for type D and type AD tumors OS. We further analyzed the metastasis trend