HOUSTON (FRONTLINE MEDICAL NEWS) – Although certain medical factors predict long-term survival in patients over age 65 years with lung cancer, advanced age and disease stage are especially strong predictors, results from a large analysis of national data demonstrated.

The findings, which were presented by Mark Onaitis, MD, at the annual meeting of the Society of Thoracic Surgeons, come from a novel effort to pair Medicare data with files from the STS General Thoracic Surgery Database (GTSD).

“Surgeons in the STS database do an excellent job taking care of these patients,” Dr. Onaitis, a thoracic surgeon at the University of California, San Diego, said in an interview. “The current survival model will allow surgeons to better estimate long-term survival of each individual patient. In addition, future analyses will identify subgroups of patients that may benefit from specific surgical approaches and procedures.”

For the current study, he and his associates linked GTSD data to Medicare data on 29,899 patients who underwent lung cancer resection from 2002 to 2013. They used Cox proportional hazards modeling to create a long-term survival model and used statistically significant univariate factors and known clinical predictors of outcome to perform variable selection.

Dr. Onaitis reported that the median age of patients was 73 years and that 52% were female. Of the 29,899 patients, 805 had a missing pathologic stage. Of the 29,094 patients not missing a pathologic stage, 69% were stage I, 18% stage II, 11% stage III, and 2% stage IV. Two-thirds of patients (66%) underwent lobectomy, followed by wedge resection (17%), segmentectomy (7%), bilobectomy (3%), pneumonectomy (3%), and sleeve lobectomy (1%). A thoracoscopic approach was performed in nearly half of resections (47%).

Cox analysis revealed the following strong negative predictors of long-term survival: having stage III or IV-V disease (hazard ratio, 1.23 and 1.37, respectively), being age 70-74 (HR, 1.19), 75-80 (HR, 1.40), or 80 and older (HR, 1.90).

After controlling for disease stage, the following procedures were associated with increased hazard of death, compared with lobectomy: wedge resection (HR, 1.22), segmentectomy (HR, 1.10), bilobectomy (HR, 1.30), and pneumonectomy (HR, 1.58). In addition, video-assisted thoracoscopic surgery was associated with improved long-term survival, compared with thoracotomy (HR, 0.86).

“Given the large number of patients and the excellent quality of the data, it was not surprising that age and stage and known medical conditions affect long-term survival,” Dr. Onaitis commented. “The deleterious effects of sublobar operations and open [as opposed to thoracoscopic or VATS] approach were more pronounced than expected.”

Other modifiable predictive factors include being a past or current smoker (HR, 1.35 and HR, 1.54, respectively) and having a body mass index below 18.5 kg/m2 (HR, 1.58).

Dr. Onaitis acknowledged certain limitations of the study, including its retrospective design. “Because the study involves linkage of STS data to Medicare data, the findings may not be applicable to patients less than 65 years of age,” he added. He reported having no financial disclosures.