By Robyn Boyle, RPh, for MDLinx | December 20, 2017
A study recently published in the Annals of Thoracic Surgery found that patients with early stage lung cancer live longer when they receive a lobectomy compared to stereotactic body radiation therapy (SBRT).
The retrospective study identified patients with biopsy-proven clinical stage I non-small cell lung cancer (NSCLC) using data from the Veteran’s Affairs Informatics and Computing Infrastructure (VINCI), a large, extensively detailed database.
Cancer-specific survival was compared among patients receiving lobectomy, sublobar resection, or SBRT. Confounders such as preoperative pulmonary function, smoking status, comorbidities, and staging workup procedures were taken into consideration.
“In this retrospective study of stage I NSCLC patients in the VA system, we found higher procedural mortality risks with surgery, although long-term survival favored lobectomy over SBRT,” wrote the authors, led by Alex Bryant from the Department of Radiation Medicine and Applied Sciences at the University of California San Diego in La Jolla, CA.
Surgery is the standard of care for early stage NSCLC, although SBRT has emerged as the preferred treatment in patients who are not candidates for surgery due to comorbidity. Compared to conventional radiation therapy, SBRT uses higher doses, fewer fractions, and highly conformal beams to deliver an ablative radiation dose to the tumor while minimizing toxicity to surrounding tissue.
Comparative data are limited, as studies evaluating differences in long-term survival between surgery and radiation in early stage NSCLC have mixed results. Three randomized trials attempting to compare surgery to SBRT closed early due to poor accrual.
Data from 4,069 patients were included in this analysis: 449 received SBRT, 2,986 underwent lobectomy, and 634 had sublobar resection. Patients were diagnosed with clinical T1 or T2a ( 5cm), N0 (no regional lymph node metastasis), or M0 (no distant metastasis) biopsy-proven NSCLS.
Patients were excluded if they had a history of prior malignancy, a missing cause of death, if they were treated more than six months after diagnosis, or were missing covariates (tumor size and grade, histology, patient age, sex, race, and tobacco history).
Interestingly, the use of SBRT increased throughout the study period from 2% in 2006 to 19% in 2015. In general, patients receiving SBRT were older and had reduced lung function compared to the surgical groups.
The researchers reported that both surgical groups had higher procedure-related mortality compared with SBRT. However, SBRT was associated with a 45% increased risk of cancer death compared with lobectomy.
Despite the higher postoperative mortality risk, the lobectomy group had the lowest unadjusted risk of all-cause mortality at 5 years. In the lobectomy group, the unadjusted 5-year overall survival was 70%, followed by sublobar resection at 56% and SBRT at 44%.
The investigators noted that prospective randomized trials with larger numbers of patients are needed to verify the results.
“The present VA data allowed comparison of a large number of clinically staged surgery patients with clinically staged SBRT patients, minimizing the issue of stage migration,” the authors concluded. “Additionally, we controlled for smoking history and baseline pulmonary function status, minimizing the effect of these important confounding variables not typically available in other large datasets. Our study findings tend to support the notion that more aggressive local therapy in early stage lung cancer may lead to improved outcomes.”
To read more about this study, click here.