Impact of smoking history on locoregional recurrence-free, distant metastasis-free survival and overall survival in Human Papillomavirus (HPV)-associated oropharyngeal cancer (OPC) treated with definitive (chemo)radiotherapy

Presentation: C043
Topic: Pharynx / Larynx Cancer
Type: Poster
Date: Thursday, April 19, 2018
Session: 9:00 AM - 7:00 PM
Authors: Howard Liu1, Anne Bernard2, Elizabeth Brown1, Laura Tam1, Matthew Foote1, Rob Milne2, Margaret McGrath1, Reza Rahbari1, Bena Cartmill1, Ben Panizza1, Sandro Porceddu1
Institution(s): 1Princess Alexandra Hospital, 2University of Queensland

Purpose: The purpose of this study was to identify if smoking history impacted on locoregional recurrence free survival (LRRFS), distant metastasis-free survival (DMFS) and overall survival (OS) in curative patients with Human Papillomavirus (HPV)-associated oropharyngeal cancer (OPC) treated with (chemo)radiotherapy and a 12-week re-staging PET/CT directed management of the neck.

Methods and Material: Patients with HPV-associated OPC treated with radiotherapy (RT) or chemoradiotherapy (chemoRT) between January 2005 and January 2016 at our institution with a predefined treatment policy were included and divided into 3 categories; non-smoker, < 10 pack-years, >/= 10 pack-years. Patients were re-staged according to the AJCC/UICC 8th Edition TNM staging. The Kaplan-Meier method was used to determine LRRFS, DMFS and OS with log-rank test used for group comparisons. LRRFS, DMFS and OS were determined from the time difference between date of treatment commencement and date of event.

Results: There were 372 consecutive eligible patients with a median age of 59 (range, 21-89) years and median follow up of 57 (range, 8-61) months. The most common T and N stage were T2 (36%) and N1 (64%), respectively, with 18% of patients having T4 and 8% N3 disease. Number of patients by stage category was I- 178 (48%), II- 107 (29%) and III- 87 (23%). Concurrent chemoRT was delivered in 351 (94%) patients. Smoking categories were non-smoker – 115 (31%), <10 pack-years – 83 (22%) and >/= 10 pack-years - 174 (47%). No significant differences in age (p=0.71), Stage (p=0.97) or use of concurrent chemotherapy (p=0.55) were observed between smoking categories. At the time of analysis 31 (8.3%) experienced locoregional failure, 43 (11.6%) distant failure and 44 (12%) had died. The 5 year LRRFS by smoking category was non-smoker – 95.3% (95% CI: 91.4-99.4%), <10 pack-years – 88.2% (95% CI: 80.2-97.1%) and >/= 10 pack-years – 88.8% (95% CI: 83.9-93.9%), respectively. No significant difference in LRRFS was observed between smoking categories (p=0.172). The 5 year DMFS by smoking category was non-smoker – 88.1% (95% CI: 81.8-94.8%), <10 pack-years – 92.6% (95% CI: 87.1-98.5%) and >/= 10 pack-years – 84.2% (95% CI: 78.6-90.2%), respectively. No significant difference in DMFS was observed between smoking categories (p=0.233). The 5-year OS of all patients was 86% (95% CI: 82.7-90.3%), for stage I – 92.3% (95% CI: 88.1-96.6%), stage II – 84.3% (95% CI: 77.2-92.1%) and stage III – 76.8% (95% CI: 67.4 – 87.4%). The 5 year OS by smoking category was non-smoker – 87.2% (95% CI: 80.9-94.0%), <10 pack-years – 87.8% (95% CI: 80.6-95.7%) and >/= 10 pack-years – 85.3% (95% CI: 79.7-91.3%), respectively. No significant difference in OS was observed between smoking categories (p=0.865).

Conclusion: Smoking history did not impact on LRRFS, DMFS or OS in this large cohort of patients with HPV-associated OPC treated with (chemo)radiotherapy and a 12-week re-staging PET/CT directed management of the neck. These findings have implications for future trial design involving this group of patients.