Long-Term Survival In Oligometastatic Head And Neck Cancer

Aggressive therapies for patients with a limited burden of metastatic disease are increasingly being administered with definitive intent in the context of clinical trials. However, outcomes in oligometastatic head and neck squamous cell carcinoma (HNSCC) patients have not been well characterized. We reviewed outcomes from 1147 patients who received intensity modulated radiotherapy (IMRT) as part of definitive management for stage I-IVB HNSCC from 2001-2013 at our institution. The primary sites included oropharynx (OPC, n = 735), oral cavity (OCC, n = 182), larynx (LRX, n = 180) and hypopharynx (HPX, n = 50). Among patients who developed distant metastatic recurrence (DM), the burden of disease was assessed by enumeration of the number of clinically or radiographically apparent tumors. Survival estimates following DM were generated using the Kaplan-Meier method and compared using log-rank testing. Cox proportional hazards models were used for univariate (UVA) and multivariate analyses (MVA). A total of 148 (13%) patients developed DM at a median time of 10.7 months (range 0.3-81.2) after IMRT. The cohort included 88 OPC, 21 OCC, 25 LRX and 14 HPX patients. The median follow-up time following DM was 48 months (range 4-131). At the time of metastasis, the median age was 61 (range 28-88), and the median Karnofsky performance status (KPS) was 80 (range 50-100). 5-year survival following DM was significantly longer in patients with a solitary metastatic lesion compared to multiple lesions (Table 1, P = 0.001). No statistically significant differences in survival were seen by pairwise comparisons of patients with 2 vs 3 vs 4 vs 5+ lesions. Of the 19 patients with solitary metastasis, 14 underwent definitive local therapy to the metastatic site with either surgery or radiotherapy. Patients who received definitive local therapy for a solitary metastasis survived longer than those who did not (5-year survival 55.7% vs 0%, P = 0.001), though the patients who did not receive local therapy were of poorer KPS. On UVA and MVA, longer survival after DM was associated with KPS>70, receipt of palliative cetuximab, non-OCC primary, longer time to metastasis and solitary metastatic tumor (MVA hazard ratio 0.31, 95% CI 0.16-0.59, P = 0.001). An oligometastatic phenotype characterizes HNSCC patients with solitary metastasis, demonstrated by a significant proportion of patients surviving 5+ years following the diagnosis of metastatic disease. These findings have important implications regarding clinical trial design for HNSCC in the recurrent and oligometastatic setting.Abstract 296; Table 1Five-year survival following distant metastasis (DM) according to number of metastatic lesions at time of DM# of metastatic lesionsN5-year survival following DM (±Std. error)11939.1% (±12.6%)2317.9% (±5.3%)3205.7% (±5.5%)4110%5+670% Open table in a new tab