Background: The National Lung Cancer Audit (NLCA) recommends that trusts obtain pathology (histology or cytology) for 75% of their lung cancer patients, however this figure was arbitrarily chosen and the optimal pathological confirmation rate is unknown, and many countries report somewhat higher rates. The aims of this study were to provide a simple means of benchmarking appropriate pathological confirmation rates by stratifying patients into groups, and whether obtaining pathology based on those groups is associated with a survival benefit.
Methods: We calculated the proportion of patients with non-small cell or small cell lung cancer in the NLCA database, first seen between 1st January 2004 and 31st December 2010, who had pathological confirmation of their diagnosis. Using logistic we assessed the independent influence of patient factors on the likelihood of having histology or cytology, and the overall effect on survival. We also used bivariate analysis to identify the features which were most strongly associated with having pathology and performed Cox regression to identify any survival advantage.
Findings: We analysed data on 136,993 individuals. Age and performance status (PS) were the strongest predictors of pathological confirmation: age ≥ 85 odds ratio (OR) 0.20 (95% confidence interval (CI) 0.19-0.22) compared with age<55; PS 4 OR 0.11 (95%CI 0.10-0.12) compared with PS 0. Pathological confirmation of diagnosis was associated with a small early survival advantage for groups 1 & 2 which represented younger patients with good PS, even after adjusting for other patient features: hazard ratio (HR) 0.93 & 0.89 respectively.
Conclusion: Stratifying patients by age and performance status is useful and appropriate when benchmarking standards for pathological confirmation of the diagnosis of lung cancer. We have shown better survival at six months and one year for younger patients with better PS, even after adjusting for confounders. Much of the survival advantage was accounted for by adjusting for the use of chemotherapy.
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