ABSTRACT
Stereotactic ablative radiotherapy (SABR) with concomitant cetuximab is an effective treatment option for previously irradiated, locally recurrent squamous cell carcinoma of the head and neck. Its local control and overall survival are similar to those of other available treatment options. Each retreatment depends heavily on the prior treatment and every patient is a special case. Based on the experience of our institution and previously published studies, for patients who receive concomitant cetuximab with a median prior radiation therapy dose of 70Gy, we recommend a total dose of 40-44Gy delivered in 5 fractions on alternating days over 1-2 weeks. However, Grade 2 or 3 toxicities are not uncommon. Therefore, in this review, we also report a pilot study that applies a normal tissue complication probability dose-response model to estimate the probability of toxicities in locally recurrent squamous cell carcinoma of the head and neck reirradiated with SABR. Although this dose-response model includes concurrent targeted therapy and no comparable model yet exists for SABR without it, complication rates without concurrent biological therapy or chemotherapy should be no higher than those described here.
Subject(s)
Carcinoma, Squamous Cell/radiotherapy , Head and Neck Neoplasms/radiotherapy , Neoplasm Recurrence, Local/radiotherapy , Radiation Injuries/epidemiology , Radiosurgery/adverse effects , Aged , Aged, 80 and over , Antineoplastic Agents/therapeutic use , Carcinoma, Squamous Cell/drug therapy , Cetuximab/therapeutic use , Combined Modality Therapy , Dose-Response Relationship, Radiation , Female , Head and Neck Neoplasms/drug therapy , Humans , Male , Middle Aged , Neoplasm Recurrence, Local/drug therapy , Pilot Projects , Radiosurgery/statistics & numerical data , Radiotherapy Dosage , Radiotherapy Planning, Computer-Assisted/methods , Retreatment , Treatment OutcomeABSTRACT
OBJECTIVES: Large brain metastases (>3 cm) present a therapeutic dilemma, as the dose delivered by stereotactic radiosurgery (SRS) in a single fraction is limited by toxicity to adjacent tissues, resulting in suboptimal local control. This study assessed the efficacy and safety of fractionated SRS for the treatment of large brain metastases. MATERIALS AND METHODS: We identified 36 patients with 37 brain metastases treated with fractionated SRS. The median SRS dose was 24 Gy (range, 12 to 27 Gy) in 2 to 5 fractions and the median treatment volume was 15.6 mL (range, 10 to 82.7 mL). Kaplan-Meier analysis was used to estimate local control and overall survival rates. RESULTS: Of the 21 lesions with available radiographic follow-up, 6 lesions (29%) had a documented local failure, yielding an actuarial progression-free survival at 6 and 12 months of 73% and 63%, respectively. The actuarial 6-month and 1-year overall survival rates were 22% and 13%, respectively. No patients in this cohort experienced acute or late complications secondary to SRS. CONCLUSIONS: Fractionated SRS is feasible and safe in patients with large brain metastases. Local control rates appear to be improved when compared with that of single fraction SRS with a relative paucity of treatment-related toxicity.