Predictors of IMRT and conformal radiotherapy use in head and neck squamous cell carcinoma: a SEER-Medicare analysis

Int J Radiat Oncol Biol Phys. 2011 Nov 15;81(4):e197-206. doi: 10.1016/j.ijrobp.2011.02.007. Epub 2011 May 17.

Abstract

Purpose: The extent to which new techniques for the delivery of radiotherapy for head and neck squamous cell carcinoma (HNSCC) have diffused into clinical practice is unclear, including the use of 3-dimensional conformal RT (3D-RT) and intensity-modulated radiation therapy (IMRT).

Methods and materials: Using the Surveillance, Epidemiology, and End Results (SEER)-Medicare linked database, we identified 2,495 Medicare patients with Stage I-IVB HNSCC diagnosed at age 65 years or older between 2000 and 2005 and treated with either definitive (80%) or adjuvant (20%) radiotherapy. Our primary aim was to analyze the trends and predictors of IMRT use over this time, and the secondary aim was a similar description of the trends and predictors of conformal radiotherapy (CRT) use, defined as treatment with either 3D-RT or IMRT.

Results: Three hundred sixty-four (15%) patients were treated with IMRT, and 1,190 patients (48%) were treated with 3D-RT. Claims for IMRT and CRT rose from 0% to 33% and 39% to 86%, respectively, between 2000 and 2005. On multivariable analysis, IMRT use was associated with SEER region (West 18%; Northeast 11%; South 12%; Midwest 13%), advanced stage (advanced, 21%; early, 9%), non-larynx site (non-larynx, 23%; larynx, 7%), higher median census tract income (highest vs. lowest quartile, 18% vs. 10%), treatment year (2003-2005, 31%; 2000-2002, 6%), use of chemotherapy (26% with; 9% without), and higher radiation oncologist treatment volume (highest vs. lowest tertile, 23% vs. 8%). With CRT as the outcome, only SEER region, treatment year, use of chemotherapy, and increasing radiation oncologist HNSCC volume were significant on multivariable analysis.

Conclusions: The use of IMRT and CRT by Medicare beneficiaries with HNSCC rose significantly between 2000 and 2005 and was associated with both clinical and non-clinical factors, with treatment era and radiation oncologist HNSCC treatment volume serving as the strongest predictors of IMRT use.

MeSH terms

  • Age Distribution
  • Aged
  • Aged, 80 and over
  • Analysis of Variance
  • Carcinoma, Squamous Cell / pathology
  • Carcinoma, Squamous Cell / radiotherapy*
  • Chemotherapy, Adjuvant / statistics & numerical data
  • Chemotherapy, Adjuvant / trends
  • Female
  • Head and Neck Neoplasms / pathology
  • Head and Neck Neoplasms / radiotherapy*
  • Health Services Research / statistics & numerical data
  • Humans
  • Male
  • Medicare / statistics & numerical data*
  • Radiotherapy, Conformal / statistics & numerical data*
  • Radiotherapy, Conformal / trends
  • Radiotherapy, Intensity-Modulated / statistics & numerical data
  • Radiotherapy, Intensity-Modulated / trends
  • SEER Program / statistics & numerical data*
  • Sex Distribution
  • Socioeconomic Factors
  • United States