Patient-oriented toxicity endpoints after head and neck reirradiation with intensity modulated radiation therapy

To characterize specific serious toxicities of reRT with intensity modulated radiation therapy (IMRT) for squamous cell carcinoma of the head and neck (SCCHN) and identify treatment-related predictors of toxicity for patient counseling and decision-making.

75 consecutive patients with recurrent or 2nd primary SCCHN received reRT from 8/2004-02/2013. All patients had prior definitive or postoperative RT. Objective endpoints of "serious toxicity" were defined as: hospitalization during reRT, tracheotomy after reRT, hemorrhage, soft tissue complication requiring operative intervention, or other CTCAE grade ≥4 toxicity.

Patients received definitive (n=41,55%) or postoperative (n=34,45%) reRT (median dose 60Gy, range 59.4-70Gy). Most patients (88%) had concurrent chemotherapy. With a median follow-up of 1.4years, 39 (52%) patients had at least one serious toxicity: hospitalization during reRT (24%), surgically-managed soft tissue complication (19%), and/or urgent tracheotomy (18%). There were no grade 5 acute toxicities but there were 4 fatal hemorrhages (median 8.3months) including 2 attributed to local-regional recurrence (LRR). Most patients (69%) had a percutaneous endoscopic gastrostomy (PEG) tube at last follow-up; those with a LRR had higher PEG tube-dependence rates (86% vs. 53%, p=0.001). LRR, site of reRT, and laryngeal RT dose, were marginally associated with toxicity-risk.

Patients considering reRT should be counseled on the high rate of PEG tube-dependence, and events of urgent tracheotomy, hospitalization, hemorrhage, and operative intervention, which typically occur months after reRT completion. Further study of baseline patient function and cumulative radiation dose to the larynx and other organs-at-risk may improve estimates of serious toxicity-risk after reRT.