3678 - Real-World Evidence on the Impact of Adjuvant Radiation Timing for HPV Related Oropharyngeal Cancer in a Nationwide Cohort
Presenter(s)
S. Yarlagadda1, M. Roy2, L. Gonzalez1, and N. S. Kalman1,3; 1Department of Radiation Oncology, Miami Cancer Institute, Baptist Health South Florida, Miami, FL, 2Department of Biostatistics, Miami Cancer Institute, Baptist Health South Florida, Miami, FL, 3Department of Oncological Sciences, Florida International University, Herbert Wertheim College of Medicine, Miami, FL
Purpose/Objective(s): Adjuvant radiation therapy (RT) for head and neck cancer (HNC) is recommended to start within 6 weeks post-surgery to minimize the package time of treatment. This recommendation predates the increased incidence of Human Papillomavirus (HPV) related oropharyngeal squamous cell carcinoma (OPSCC), which carries a more favorable prognosis. Recent studies reported no difference in outcomes with increased package time in HPV related OPSCC. We used the National Cancer Database (NCDB) to assess the impact of package time on overall survival (OS) in HPV related OPSCC.
Materials/Methods:
The NCDB was queried for HPV related OPSCC patients that received surgery and adjuvant RT. Package time was defined as the duration between the date of surgery and the date of RT completion, comparing normal package time (= 13 weeks or 91 days) versus prolonged package time (>13 weeks or 91 days). Time from surgery to RT (TSRT) was defined as the duration between the date of surgery and the date of RT start, comparing normal TSRT (= 6 weeks or 42 days) versus prolonged TSRT (>6 weeks or 42 days). Kaplan-Meier survival analysis was used to determine 2-year and 5-year OS. Log rank test was used to compare OS between the groups. Cox multivariable regression was used to determine the factors impacting OS.Results:
Out of 154650 HNC cases, 8167 were non-metastatic HPV related OPSCC. Of these, 1650 patients met the study criteria and were included in the analysis. Median age was 60 years (range [R]: 28-89 years), and the majority were male (85%) and white (93%). AJCC stage was cT1 in 42.1%, cT2 in 47.8%, cT3 in 7.0%, and cT4 in 3.1%; cN0 in 15.4%, cN1 in 69.1%, cN2 in 12.2%, cN3 in 2.1%, and cNx in 1.1%. Roughly half of patients (53.2%) received concurrent chemoradiation. The normal package time group had 940 patients (56.97%), while the prolonged package time group had 710 patients (43.03%); the normal TSRT group had 847 patients (51.3%) and the prolonged TSRT group had 803 patients (48.7%). Median OS was not reached in either group; 2-year and 5-year OS in the entire cohort was 94.9% (95% CI: 93.8-96%) and 85.4% (95% CI: 82.8-88.0%), respectively. OS did not differ significantly between normal and prolonged package time or TSRT (Table 1). Prolonged package time (HR: 2.79 [95% CI: 0.99-7.84], p=0.05) and TSRT (HR: 0.79 [95% CI: 0.27-2.29], p=0.67) were not significant on Cox regression.Conclusion: For HPV related OPSCC, prolonged package time and TSRT showed no significant impact on OS in a nation-wide cohort.
Table 1: 2-year and 5-year Overall Survival (OS) with 95% Confidence Intervals in each group| Arm | 2-year OS (95% CI) | 5-year OS (95% CI) | p-value |
| Whole cohort | 94.9% (93.8%-96.0%) | 85.4% (82.8%-88.0%) | |
| Package Group | 0.0936 | ||
| Normal | 94.9% (93.5%-96.3%) | 88.2% (85.4%-90.9%) | |
| Prolonged | 94.9% (93.3%-96.6%) | 81.4% (76.3%-86.4%) | |
| TSRT Group | 0.7122 | ||
| Normal | 94.5% (92.9%-96.0%) | 87.0% (84.1%-90.0%) | |
| Prolonged | 95.4% (93.9%-96.9%) | 83.5% (79.1%-87.8%) |