Examining tumor control and toxicity after stereotactic body radiotherapy in locally recurrent previously irradiated head and neck cancers: implications of treatment duration and tumor volume.

BACKGROUND: Stereotactic body radiotherapy (SBRT) has been studied in locally recurrent previously-irradiated head and neck cancers; however, the optimum fractionation and patient selection continues to be defined.

METHODS: Patients (n = 132) with locally recurrent head and neck cancer salvaged via SBRT ± cetuximab (median, 44 Gy/5 fractions) from November 2004 to May 2011 were retrospectively reviewed. Disease outcomes and toxicity were analyzed by predictive factors including treatment duration and tumor volume.

RESULTS: At a median 6-month follow-up (range, 0-55 months), treatment duration <14 days was associated with significantly improved recurrence-free survival (RFS) at the expense of increased late toxicity (p = .029). Tumor volume >25 cc remained a significant predictor of inferior survival and tumor control, and was associated with significantly more acute toxicity (p = .017) but no difference in late toxicity.

CONCLUSION: SBRT ± cetuximab achieves promising tumor control and survival with low rates of acute/late toxicity even for recurrences >25 cc. Prolongations in treatment time may decrease late toxicity at the expense of disease control.