Elsevier

European Journal of Cancer

Volume 48, Issue 18, December 2012, Pages 3386-3395
European Journal of Cancer

The effect of comorbidity on stage-specific survival in resected non-small cell lung cancer patients

https://doi.org/10.1016/j.ejca.2012.06.012Get rights and content

Abstract

Aim

To quantify the effect of comorbidity on stage-specific survival in resected non-small cell lung cancer (NSCLC) patients.

Methods

From the Danish Lung Cancer Registry, 20,461 patients diagnosed with lung cancer between 1st January 2005 and 31st December 2010 were identified. Among 3152 NSCLC patients who underwent surgical resection, mortality hazard ratios were calculated during three consecutive time periods following surgery (0–1 month, 1 month–1 year and >1 year) according to Charlson comorbidity score (CCS 0, 1, 2, 3+), Eastern Cooperative Oncology Group (ECOG) performance status, lung function, age, sex, pathological T (pT) and N (pN) stage using Cox proportional hazard modelling. The Kaplan Meier method was used to describe stage-specific survival according to the CCS.

Results

Severe comorbidity (CCS 3+) was independently associated with significantly higher death rates throughout the three periods of follow-up [Hazard ratio (HR) 2.06 (1.13–3.75) for CCS 3+ in 0–1 month, 1.57 (1.17–2.12) 3+ during1 month–1 year and 1.84 (1.42–2.37) after 1 year]. Stage-specific 5-year survival in patients with severe comorbidity was significantly lower than in patients without comorbid disease [e.g. 38% (95% confidence interval (CI) 23–53%) for pT1 and CCS 3+ versus 69% (62–75%) for pT1 and CCS 0].

Conclusion

Severe comorbidity affects survival of NSCLC patients who undergo surgical resection by as much as a single stage increment and this effect persists throughout follow-up. Further research may be necessary to help identify which patients are most likely to benefit from surgery.

Introduction

Surgical resection is the principal treatment for non-small cell lung cancer (NSCLC) patients with early stage disease, but only around 20% of patients are eligible for surgery at the time of diagnosis. Pathological tumour stage is the most powerful predictor of long-term survival, and the revised 7th edition tumour-node-metastasis (TNM) lung cancer staging system provides better prognostic value than previous versions.1 However, there remains great variation in prognosis and survival between patients with similar stage lung cancer.

A range of factors, including lung function, age, performance status and comorbidity are known to affect survival of NSCLC patients who undergo surgical resection. Patients diagnosed with lung cancer often have severe comorbidity that adversely affects overall survival. The most common comorbid conditions in lung cancer patients are age- and tobacco-related illnesses such as cardiovascular disease, chronic obstructive pulmonary disease (COPD) and other malignancies.2 There is evidence that the presence of comorbid conditions is an independent prognostic factor in patients with resected stage I NSCLC.3, 4, 5, 6, 7

Most of the available studies were conducted using the 6th edition of the TNM lung cancer staging system, which allowed for less accurate survival predictions and may have affected the relative prognostic importance of comorbidity. Moreover, most studies were small or based on a single-institution series of patients. In the present study, we investigated the effect of comorbidity on stage-specific survival in a population-based study of NSCLC patients who underwent surgical resection in Denmark between 2005 and 2010.

Section snippets

Patients

The Danish Lung Cancer Registry (DLCR) was established in 2000, and has since collected data on diagnostic procedures, staging, surgical procedures and complications, oncological treatment and survival through nationwide registration of clinical information on all lung cancer patients from the 37 hospital departments involved in the treatment of lung cancer in Denmark. Through record linkage, patient records are complemented with data from national databases: demographic information is

Results

Table 1 shows an overview of all 20,461 lung cancer patients identified in the DLCR between 2005 and 2010, according to CCS. A high CCS was more common in older patients (aged 70 and over), patients with a poor performance status (ECOG = 2 or greater), patients with a predicted FEV1 of less than 50% and among males. Patients with severe comorbidity were more likely to be treated with a wedge resection or not to undergo surgery (p < 0.001). No differences in clinical TNM stage or histological type

Discussion

In this study, we observed that comorbidity impairs survival in resected NSCLC patients, and that this effect is not confined to the peri-surgical or intermediate period. Severe comorbidity was found to affect stage-specific survival to the extent that the difference in survival is as big as an increment in stage group.

This is the first study that addresses the effect of comorbidity on survival among resected NSCLC patients in a large, unselected, population-based cohort of lung cancer

Conclusion

The results from this large, nation-wide, population-based group of NSCLC patients who had undergone surgical resection show that severe comorbidity impairs survival throughout a long period post-surgery by as much as a single stage increment. More detailed studies are required to identify characteristics of NSCLC patients with locally advanced disease and/or comorbidity who might benefit from surgical resection.

Conflict of interest statement

None of the authors have conflicts of interest to declare.

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