Laryngeal Squamous Cell Carcinoma: Is Adherence to Quality Metrics Associated with Improved Survival?

January 20, 2017
PENTAX Medical

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Background:

In 2009, the American Head and Neck Society (AHNS) approved a set of quality measures for the pretreatment, treatment, and posttreatment of patients with laryngeal squamous cell carcinoma (SCC). Per these metrics, pretreatment evaluation should include complete head and neck examination and documentation of TNM staging; treatment-related evaluation should consist of multidisciplinary consultation or tumor board; and posttreatment surveillance should include regular follow-up. Similar quality metrics have since been set forth by the National Comprehensive Cancer Network (NCCN).

While adherence to these metrics has been viewed as a means to assess quality of care for patients with SCC, the actual correlation between compliance and survival has not been firmly established. This study aims to explore the association between improved survival and adherence to proposed quality metrics in patients with laryngeal SCC treated with surgery with or without adjuvant therapy.

Methods:

A retrospective cohort study included 243 patients (184 men and 59 women; median age 62) who underwent primary surgical treatment for laryngeal SCC at Washington University School of Medicine from January 1, 2003 through December 31, 2012.

Outcome measures included compliance rates with quality metrics and measures of overall survival (OS), disease-specific survival (DSS), and disease-free survival (DFS).

Results:

Five-year OS, DSS, and DFS rates were 85% (95% CI, 81-90%), 86% (95% CI, 81-91%), and 78% (95% CI, 73-83%), respectively.

The median compliance rate was 85% for the 14 AHNS quality metrics and 78% for the 11 NCCN measures. Tobacco cessation counseling and referral to a speech-language pathologist for pre-laryngectomy counseling were the two individual AHNS and NCCN metrics with the lowest compliance (16.2% and 18.2%, respectively). Metrics with the highest compliance were complete head and neck examination, laryngeal examination, and biopsy (all 100%), and radiologic studies of the head and neck (98.8%).

Patients with 100% compliance with the 14 AHNS metrics experienced significantly better OS (P=0.006) and DFS (P=0.048), in addition to a strong trend toward improved DSS (P=0.07), compared to patients with other compliance rates. There was also an increased risk of death in the 80-99% compliance group compared with the 100% compliance group (95% CI, 1.03-4.7). No significant differences were found across any of the survival metrics between the 80-99% compliance group and the group with a compliance rate of 79% or less.

With regards to adherence to NCCN guidelines, there were no differences in OS, DSS, or DFS for different levels of compliance (P=0.05 for OS, 0.19 for DSS, and 0.3 for DFS). 

Notably, when individual AHNS and NCCN metrics were evaluated, multidisciplinary evaluation through consultation or tumor board for patients with advanced T-stage or nodal disease was the only metric for which compliance was associated with improved survival (OS aHR, 0.47; 95% CI, 0.24-0.94; DFS aHR, 0.45; 95% CI, 0.23-0.85).

Elective neck dissection with 18 lymph nodes or more was also found to be associated with improved DFS (aHR 0.36; 95% CI, 0.14-0.99). A negative-margin resection at the time of initial surgery was associated with improved OS, DSS, and DFS (HR, 0.48; 95% CI, 0.26-0.9; HR, 0.37; 95% CI, 0.18-0.77; and HR, 0.55; 95% CI, 0.31-0.97, respectively).

Discussion:

In surgically treated patients with laryngeal SCC, there was no consistent correlation between increasing levels of compliance with quality metrics and improved survival. However, differences in survival did exist between patients with 100% adherence to AHNS or NCCN metrics and those with lower levels of compliance.

One major study finding is the consistent and significant correlation of improved survival with multidisciplinary evaluation via tumor board or consultation in surgically treated patients with laryngeal SCC. This result aligns with those of previous studies, which associate pretreatment multidisciplinary evaluation with favorable oncologic outcomes. Intriguingly, this same association was not found in patients with oral cavity SCC, suggesting that head and neck quality metrics may be site-specific, a hypothesis that warrants further exploration.

Another major study finding is the association of lymph node yield of 18 or more during elective neck dissection with improved DFS, and the association of negative-margin resection at the time of initial surgery with improved OS, DSS, and DFS. These metrics warrant further study as potential quality metrics for surgically treated laryngeal SCC.

Conclusion:

Increasing levels of compliance with AHNS and NCCN quality metrics is not associated with improved survival in a dose-response relationship. Multicenter studies with a larger sample size are needed to bolster the generalizability of these study results and to develop better quality metrics that predict survival for patients with surgically treated laryngeal SCC.

Reference:

Graboyes, EM et al. “Evaluation of Quality Metrics for Surgically Treated Laryngeal Squamous Cell Carcinoma. JAMA Otolaryngol Head Neck Surg 2016; 142 (12): 1154-1163. Accessed January 12, 2017.

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