Although lobectomy is considered the standard treatment for early-stage NSCLC, we found that limited resections were commonly performed in this study population, with sublobar resections representing greater than 20% of all procedures performed for patients with stage I or II disease. This relatively high frequency likely reflects both the extent of comorbidity seen in patients with lung cancer and ongoing disagreement concerning the appropriate role for limited resection in the treatment of NSCLC. In adjusted analyses of patient-specific factors, Medicare, Medicaid, lack of or unknown type of insurance, small tumor size, increasing severity of lung disease, and history of stroke were independently associated with receipt of a limited resection. Receipt of limited resection was not associated with age, race or ethnicity, or income. From the provider perspective, thoracic surgery specialty, practice at an NCI-designated cancer center, and non–fee-for-service compensation were all associated with higher odds of performing limited resection.
Previous literature exploring the impact of socioeconomic factors on lung cancer care processes and outcomes has primarily focused on survival differences or whether appropriate patients received any surgical treatment. Greenberg et al. (25
) found that NSCLC patients with private insurance were more likely to be treated with surgery, whereas McDavid et al. (26
) found a 10% decrease in 3-year survival after lung cancer diagnosis for patients with no insurance vs private insurance (13% vs 23%, respectively). Higher income has also been associated with receipt of surgical treatment of NSCLC and increased likelihood of achieving 5-year survival (27
). Similarly, lower education levels have been found to be associated with a decreased likelihood of surgical treatment (29
). In our study, insurance status, but not income or education, was associated with the type of surgical resection received in the adjusted analysis. This association could represent a provider bias against certain insurance types.
Use of limited resection for very small tumors has been extensively debated in the literature, with advocates both for and against consideration of sublobar resection for tumors smaller than a variety of size thresholds (6
). This study confirmed that tumor size is an important determinant of the choice of resection type. A randomized controlled trial of sublobar resection vs lobectomy for stage IA tumors less than 2 cm in diameter is ongoing, with completion expected in 2012 (34
Additionally, our results indicate that patients’ overall health and comorbid conditions affect the decision whether to use a limited resection. Increasing severity of lung disease and a history of stroke were associated with receipt of limited resection, indicating that sublobar resections can serve as an alternative approach for those unable to tolerate lobectomy. Whereas limited resections are also often advocated for the elderly (10
), we did not find an association between age and resection type in this cohort.
The finding of higher frequency of limited resection by thoracic surgeons at NCI-designated cancer centers could reflect either a tendency for surgeons at those hospitals to perform sublobar resections rather than declaring a patient a nonsurgical candidate or a tendency for higher risk patients to be referred to tertiary treatment centers. The method of compensation is known to affect physician behavior, with evidence of earlier diagnosis of some cancers in the HMO relative to the fee-for-service setting (37
). Our results suggest that surgeon payment method could also affect the type of resection performed, with limited resections performed less often in fee-for-service than salary-based practices. This finding may in part be due to lower Medicare reimbursement for some limited resections, depending on the procedure performed. National average reimbursement rates range from $808 for a thoracoscopic wedge to $1491 for a segmentectomy, in contrast to $1537 to $1642 for a lobectomy (41
Comparing short-term outcomes after limited resection and lobectomy, we found no difference in postoperative complications, consistent with previous findings of the Lung Cancer Study Group (6
). The higher 30-day mortality rate in the limited resection group likely reflects underlying comorbidity differences, as the discrepancy in rates became non-statistically significant after adjustment for baseline patient characteristics. Although we ascertained many postoperative complications, our morbidity data did not include some events that are traditionally monitored after thoracic surgery, including prolonged air leak or chest tube requirement, recurrent laryngeal nerve injury, or new atrial arrhythmias. Our complication rate is thus lower than reported in other series (42
Like the Lung Cancer Study Group’s randomized controlled trial of lobectomy vs limited resection (6
) and a recent Surveillance, Epidemiology, and End Results–Medicare analysis of patients with tumors sized 3 cm in diameter or less (13
), this study showed a trend of improved survival with lobectomy; however, this trend was non-statistically significant before and after adjustment for differences in patient characteristics. Examination of all-cause mortality reflects the risk of death both due to cancer and from unrelated illnesses. Due to poorer baseline health, we expected a higher rate of death due to competing causes in the limited resection group, and persistence of this difference even after adjustment may be due to unobserved clinical factors.
Strengths of this study include the use of a large multiregional patient cohort. It encompassed a wide range of practice settings, extensive rigorously collected data, and a contemporary timeframe that reflects recent advances in medical and surgical care.
This study also had limitations inherent in retrospective analyses of observational data. Patients who underwent sublobar resections were different than those chosen to undergo lobectomy. Unmeasured selection effects in an observational study can make it difficult to determine definitely whether a potential survival benefit is a true consequence of resection type. We did not ascertain differences in cause of death or disease-free survival.
In summary, this evidence was statistically inconclusive; however, it suggested that lobectomy may be associated with greater long-term survival than limited resection in patients with early-stage lung cancer. Some clinical, socioeconomic, and surgeon factors were statistically significantly associated with the choice of surgical resection for early-stage NSCLC. We believe that providers should seek to reduce the impact of socioeconomic factors such as patient insurance status and surgeon compensation type on clinical decision making.