Nomogram Predicts Delayed Postsurgery RT Initiation in HNSCC

Study findings showed that a nomogram that generates individualized estimates of postoperative radiotherapy (PORT) initiation delay in patients with head and neck squamous cell carcinoma (HNSCC) could improve pretreatment counseling and intervention (JAMA Otolaryngol Head Neck Surg. 2020 Apr 2. Epub ahead of print).

“The standard of care for initiation of [PORT] in [HNSCC] is within 6 weeks of surgical treatment. Delays in guideline-adherent PORT initiation are common, associated with mortality, and a measure of quality care, but patient-specific tools to estimate the risk of these delays are lacking,” explained Dylan A. Levy, BS, Department of Otolaryngology–Head & Neck Surgery, Medical University of South Carolina, Charleston, and colleagues.

Thus, Dr Levy et al created 2 nomograms for predicting delayed PORT initiation based on pre- and post-surgical data and sought to validate them in a cohort study. Both nomograms were developed to predict risk for PORT initiation delay using variables, including race/ethnicity, insurance type, tumor site, and facility type.

Individually, the nomogram based on presurgical variables included clinical stage and comorbidity severity, whereas the nomogram with postsurgical variables included US region, length of stay, and care fragmentation.

Using the National Cancer Database, data for 60,766 adults with HNSCC who had surgery and PORT at a Commission on Cancer–accredited facility were obtained between January 2004 and December 2015.

The end point was PORT initiation >6 weeks after the surgical intervention. Multivariable logistic regression models were developed in 80% of the sample (derivation cohort; n = 48,625) and internally validated with bootstrapping, assessed for discrimination by calibration plots and the concordance (C) index, and externally validated in the remaining 20% (validation cohort; 12,151).

Ultimately, data were analyzed between June 2, 2019, and January 29, 2020, and the rate of PORT delay was found to be 55.8% in the derivation cohort and 56.7% in the validation cohort.

For the presurgical nomogram, the concordance indices were 0.670 (95% CI, 0.664-0.676) and 0.674 (95% CI, 0.662-0.685) in the derivation and validation cohorts, respectively. For the nomogram with postsurgical variables, the concordance indices were 0.691 (95% CI, 0.686-0.696) and 0.694 (95% CI, 0.685-0.704), respectively.

“This study found that a nomogram developed with presurgical data to generate personalized estimates of PORT initiation delay may improve pretreatment counseling and the delivery of interventions to patients at high risk for such a delay,” Dr Levy and colleagues said.

“A nomogram including postsurgical data can drive institutional quality improvement initiatives and enhance risk-adjusted comparisons of delay rates across facilities,” they concluded.—Hina Porcelli