A nomogram to predict loco-regional control after re-irradiation for head and neck cancer

Abstract

Background and purpose: Loco-regionally recurrent head and neck cancer (HNC) in the setting of prior radiotherapy carries significant morbidity and mortality. The role of re-irradiation (re-RT) remains unclear due to toxicity. We determined prognostic factors for loco-regional control (LRC) and formulated a nomogram to help clinicians select re-RT candidates.

Material and methods: From July 1996 to April 2011, 257 patients with recurrent HNC underwent fractionated re-RT. Median prior dose was 65 Gy and median time between RT was 32.4 months. One hundred fifteen patients (44%) had salvage surgery and 172 (67%) received concurrent chemotherapy. Median re-RT dose was 59.4 Gy and 201 (78%) patients received IMRT. Multivariate Cox proportional hazards were used to identify independent predictors of LRC and a nomogram for 2-year LRC was constructed.

Results: Median follow-up was 32.6 months. Two-year LRC and overall survival (OS) were 47% and 43%, respectively. Recurrent stage (P=0.005), non-oral cavity subsite (P<0.001), absent organ dysfunction (P<0.001), salvage surgery (P<0.001), and dose >50 Gy (P=0.006) were independently associated with improved LRC. We generated a nomogram with concordance index of 0.68.

Conclusion: Re-RT can be curative, and our nomogram can help determine a priori which patients may benefit.

Keywords: Head and neck cancer; Intensity modulated radiation therapy; Re-irradiation; Recurrent head and neck cancer.