Radiotherapy delays do not predict survival, recurrence in oropharynx carcinoma

Treatment delays do not necessarily contribute to cancer-specific survival (CSS) or locoregional recurrence (LRR) in patients with oropharynx carcinoma, reveals a study. However, time on treatment (TOT) of 1 to 3 days is associated with lower CSS.

A team of researchers performed a retrospective analysis to examine the prognostic significance of treatment delays for oropharynx carcinoma patients treated with definitive radiotherapy (RT), comparing p16⁺ with p16⁻ disease. A total of 763 patients treated between 2012 and 2016 were included in the analysis.

Treatment delay was defined as the time from pathologic diagnosis to RT initiation; to stratify outcomes, the following thresholds were used: ≤60, 61 to 90, and >90 days. TOT delays were estimated based on the RT fractionation, and TOT delay of 1 to 3 days was compared with >3 days. Finally, the researchers performed multivariable analysis to determine the predictors of CSS and LRR.

Of the patients, 650 (85 percent) had p16⁺ disease. Multivariable analysis revealed the association of a TOT delay of 1 to 3 days with inferior CSS (hazard ratio [HR], 1.81, 95 percent confidence interval [CI], 1.02‒3.22) compared with <1 day.

On the other hand, treatment delay >90 vs ≤60 days (HR, 1.68, 95 percent CI, 0.98‒3.04) and 61 to 90 vs ≤60 days (HR, 0.94, 95 percent CI, 0.60‒1.48) showed no association with CSS.

Furthermore, treatment delay >90 versus ≤60 days (HR, 1.29; 95 percent CI, 0.66‒2.52), 61 to 90 vs ≤60 days (HR, 0.98, 95 percent CI, 0.64‒1.52), TOT 1 to 3 vs <1 day (HR, 0.91, 95 percent CI, 0.39‒2.11), and TOT >3 vs <1 day (HR, 1.79, 95 percent CI, 0.80‒3.99) did not correlate with LRR. Treatment delay also showed no interaction with p16 status in relation to LRR (p=0.27) or CSS (p=0.17).

“[A] p16 status should not be a significant factor when triaging RT start dates,” the researchers said.