Recurrent and second primary head-and-neck squamous cell carcinomas (HNSCC) arising within or close to previously irradiated areas are a significant clinical challenge. Salvage surgical resection is the standard of care, but reirradiation is the only potentially curative treatment when surgery is not an option. Reirradiation is more challenging than initial treatment because of the side effects of prior therapy and concerns about the risks of high cumulative radiation doses to normal structures. Multi-institutional trials and large single institutional experiences have demonstrated that aggressive reirradiation, most often with chemotherapy, is feasible and provides durable locoregional control in some patients.
An Expert Consensus on Reirradiation
In the August 1, 2011 International Journal of Radiation Oncology * Biology * Physics, the American College of Radiology (ACR) published appropriateness criteria for recurrent head and neck cancer after prior definitive radiation. The ACR expert panel recommended that patient evaluation and reirradiation for HNSCC be performed at a tertiary care center with a head and neck oncology team that is equipped with the resources and experience to manage the complexities and toxicities of retreatment.
Evaluation of Patients with Head & Neck Cancer
Patient evaluation is important in assuring only appropriate patients are offered reirradiation. Evaluation should include careful restaging imaging, a detailed history and assessment of life expectancy, access to the prior radiotherapy details, and evaluation of:
Speech and swallowing function.
Sequelae of previous treatment (eg, fibrosis, carotid stenosis, osteoradionecrosis, or other severe toxicity).
The ACR recommends that patients with a reasonable performance status who do not have severe soft tissue or bone toxicities from prior therapy and do not have distant metastatic disease are likely benefactors of reirradiation. However, additional data is needed to identify patient subgroups most likely to benefit from reirradiation.
There is currently no single optimal treatment schema for reirradiation of patients with HNSCC due to widely ranging differences in the location and extent of recurrent tumor, initial radiation parameters, amount of time since prior treatment, degree of existing normal tissue toxicity, and limitations of available data on normal tissue recovery from prior treatment and tolerance to reirradiation. Most reirradiation experiences have targeted the recurrent gross disease with limited margin, without elective nodal reirradiation. The chance of local control is higher in patients receiving an additional dose of at least 60 Gy. Advanced radiation techniques (eg, intensity modulated radiation, stereotactic body radiosurgery, or proton therapy) are often used to protect nearby critical normal structures.
Patient selection is a key step in determining which patients should be offered reirradiation.
Making Treatment Decisions: Reirradiation & Chemotherapy
The prognosis for recurrent HNSCC treated with chemotherapy is poor, with the average survival time being about 1 year. The overall 2-year survival rate is just 26%. Still, these data demonstrate superiority to those seen in separate trials of patients treated with palliative chemotherapy alone. Retrospective data in patients undergoing reirradiation suggests that overall survival can improve if local control is obtained. While toxicities may be reduced with newer targeted radiation modalities, 28% to 40% of patients reirradiated with conventional radiation techniques experienced significant toxicities. This underscores the need for appropriate patient selection and education, and treatment by a skilled head and neck oncology team. Practitioners are encouraged to visit the ACR appropriateness criteria website (www.acr.org/ac) for assistance in making the most appropriate treatment decisions.