896P - Day of the week of chemotherapy (CT) during concurrent chemoradiation (CRT) for oropharyngeal squamous cell carcinoma (OPSCC)

Background

CRT is the standard-of-care treatment for locoregionally advanced OPSCC. Clinical trials with CRT request CT be given at the beginning of the week (Mon-Wed). However, in clinical practice, patients (pts) undergoing CRT may be given CT any day of the week. The objective of this study was to assess if day of the week of CT during CRT impacts treatment outcomes.

Methods

Retrospective study of 735 OPSCC pts treated with curative-intent CRT at MD Anderson between 2002 and 2013. Clinicopathologic characteristics of both groups were compared by chi-square test and/or Wilcoxon rank-sum test. Time-to-event analysis was conducted by Kaplan-Meier method, log-rank test, and cox proportional hazards model. Primary endpoints were recurrence rate (RR), time to recurrence (TTR), recurrence-free survival (RFS), and overall survival (OS).

Results

Of 735 pts, 648 (88%) were male and 417 (57%) were current or former smokers. For 414 (56%) pts, HPV status was known, with 329 HPV-positive and 39 HPV-negative. The large majority of pts (697, 95%) had base of tongue or tonsil primary site. Most frequent TNM stage by AJCC 7th ed. at diagnosis was T3-T4 (379, 52%) and N2a-N2b (430, 59%). Cisplatin was the most used agent (360, 49%), with CT mostly on a weekly schedule (557, 76%). Most frequent radiation therapy was conventional fractionation (588, 80%) with 545 pts (74%) receiving ≥ 7000 rads. Pts were divided into two groups based on day of the week of CT: Monday/Tuesday/Wednesday (M/T/W; 632, 86%) vs Thursday/Friday (T/F; 103, 14%). Groups were balanced for all clinicopathologic characteristics, except for gender (p=0.03), RT dose received (p=0.04), and CT regimen (weekly vs. every 3 weeks, p<0.0001). There was no significant difference in RR between groups, with M/T/W RR 21% vs T/F RR 29% (p=0.07). Median OS was 155 mo (95%CI 145-NR) with no significant difference between M/T/W and T/F (HR 1.19 [0.84 − 1.69], p=0.34). Median RFS was 155 mo (95%CI 143-NR) with no significant difference between M/T/W and T/F (HR 1.22 [0.87 − 1.72], p=0.25). Median TTR was not reached, with no significant difference between M/T/W and T/F (HR 1.46 [0.96 − 2.22], p=0.07).

Conclusions

The day of the week of CT during CRT does not appear to impact recurrence or survival outcomes.

Clinical trial identification

Editorial acknowledgement

Funding

Has not received any funding.

Disclosure

R. Ferrarotto: Financial Interests, Personal, Advisory Board: Regeneron-Sanofi, Ayala Pharmaceuticals, Bicara Therapeutics, Prelude Therapeutics, Guidepoint, Elevar Therapeutics, G1 Therapeutics, ExpertConnect, Remix; Financial Interests, Personal, Invited Speaker: Merck; Financial Interests, Personal, Royalties: UptoDate; Financial Interests, Institutional, Coordinating PI: Merck, Gennentech, Pfizer, Ayala, EMD Serono; Financial Interests, Institutional, Other, Co-PI: Rakuten, Nanobiotix; Financial Interests, Institutional, Local PI: Prelude, ISA Therapeutics; Non-Financial Interests, Advisory Role: Cellestia. All other authors have declared no conflicts of interest.