Source: Journal of Clinical Oncology, Vol 26, No 21 (July 20), 2008
Authors: Mitchell Machtay et al.

Purpose:
Concurrent chemoradiotherapy (CCRT) for squamous cell carcinoma of the head and neck (SCCHN) increases both local tumor control and toxicity. This study evaluates clinical factors that are associated with and might predict severe late toxicity after CCRT.

Methods:
Patients were analyzed from a subset of three previously reported Radiation Therapy Oncology Group (RTOG) trials of CCRT for locally advanced SCCHN (RTOG 91-11, 97-03, and 99-14). Severe late toxicity was defined in this secondary analysis as chronic grade 3 to 4 pharyngeal/laryngeal toxicity (RTOG/European Organisation for the Research and Treatment of Cancer late toxicity scoring system) and/or requirement for a feeding tube  2 years after registration and/or potential treatment-related death (eg, pneumonia) within 3 years. Case-control analysis was performed, with a multivariable logistic regression model that included pretreatment and treatment potential factors.

Results:
A total of 230 patients were assessable for this analysis: 99 patients with severe late toxicities and 131 controls; thus, 43% of assessable patients had a severe late toxicity. On multivariable analysis, significant variables correlated with the development of severe late toxicity were older age (odds ratio 1.05 per year; P = .001); advanced T stage (odds ratio, 3.07; P = .0036); larynx/hypopharynx primary site (odds ratio, 4.17; P = .0041); and neck dissection after CRT (odds ratio, 2.39; P = .018).

Conclusion:
Severe late toxicity after CCRT is common. Older age, advanced T-stage, and larynx/hypopharynx primary site were strong independent risk factors. Neck dissection after CCRT was associated with an increased risk of these complications.

Authors:
Mitchell Machtay, Jennifer Moughan, Andrew Trotti, Adam S. Garden, Randal S. Weber, Jay S. Cooper, Arlene Forastiere, K. Kian Ang

Authors’ affiliations:
From the Jefferson Medical College and Kimmel Cancer Center of Thomas Jefferson University; Radiation Therapy Oncology Group Headquarters and Statistical Center and the American College of Radiology, Philadelphia, PA; Moffitt Cancer Center of University of South Florida, Tampa, FL; Departments of Radiation Oncology and Head and Neck Surgery, M.D. Anderson Cancer Center, Houston, TX; Maimonides Medical Center, NY; and Johns Hopkins University Medical Center, Baltimore, MD