Original ResearchComparison of long-term survival outcomes between stereotactic body radiotherapy and sublobar resection for stage I non-small-cell lung cancer in patients at high risk for lobectomy: A propensity score matching analysis
Introduction
Lung cancer is the leading cause of cancer-related deaths worldwide [1]. The number of cases of stage I lung cancer is expected to increase when low-dose computed tomography (CT) screening is introduced because CT can detect more stage I cancer cases than chest radiography [2]. The U.S. Preventive Services Task Force recommends annual low-dose CT screening in individuals with a specific smoking history [3]. The treatment of stage I non-small-cell lung cancer (NSCLC) detected by CT screening is of increasing importance, particularly in high-risk operable patients [4], [5], [6]. Although lung cancer mortality has tended to decline over the last decade according to the age-adjusted incidence, the crude rate of lung cancer deaths remains high in the elderly [7], [8]. As such the optimum treatment of early stage NSCLC in elderly individuals or those with medical comorbidities remains unclear.
Lobectomy remains the standard treatment for patients with clinical stage I NSCLC who can tolerate the type of surgery [9], [10], even in the elderly. According to a recently updated opinion paper by the European Organisation for Research and Treatment of Cancer (EORTC) and the International Society of Geriatric Oncology (SIOG), surgical treatment should not be denied to elderly patients simply because of their age [11]. However, the percentage of patients undergoing surgery decreases with advancing age, even in patients with no comorbidities [12]. The EORTC/SIOG paper also refers to consideration of limited resections in the elderly, as well as stereotactic body radiotherapy (SBRT) in individuals who are medically inoperable.
Sublobar resection (SLR) is thought to result in inferior survival compared with lobar resection based on the results of a randomised trial [13]. This type of surgery is considered for patients with major comorbidities, and as well as individuals with a peripheral nodule of ⩽2 cm with favourable findings [10]. In addition, Rami-Porta and Tsuboi reported that lobectomy and wedge resection result in similar survival in patients aged ⩾71 years [14]. The American College of Surgeons Oncology Group (ACOSOG) Z4032 and Z4099 defined criteria of ‘high risk’ for lobectomy that included pulmonary function as the major criterion, and age and other medical comorbidities as minor criteria.
SBRT is being a standard treatment option for compromised patients who are medically unfit for any type of surgery due to advanced age or comorbidities [10]. Multicentre prospective trials revealed that SBRT was safe and effective in patients with inoperable stage I NSCLC [15], [16], [17]. The introduction of SBRT decreased the number of untreated elderly Dutch patients with early stage NSCLC [18].
The optimal treatment for high-risk operable patients who might tolerate surgical intervention but not lobectomy remains controversial [19], [20]. To resolve this issue, an inter-group randomised trial (Radiation Therapy Oncology Group [RTOG] 1021/ACOSOG Z4099) comparing SBRT with SLR in high-risk patients with stage I NSCLC was initiated. However, it was closed in May 2013 due to slow patient enrolment. Therefore, there are no available data comparing SBRT and SLR based on a prospective randomised trial. The aim of the current study was to perform retrospective survival comparisons between SBRT and SLR in patients who underwent treatment due to medical comorbidities.
Section snippets
Patient population
This study retrospectively reviewed consecutive patients who underwent SBRT or SLR because of medical comorbidities for clinical stage I NSCLC. Data were obtained from databases maintained by the Departments of Radiation Oncology and Thoracic Surgery of Kyoto University Hospital. Clinical stage was determined using CT and 18F-fluorodeoxyglucose positron emission tomography (FDG-PET), or with CT alone. Patients with a tumour diameter >50 mm or those without histological confirmation of NSCLC were
Results
Between January 2003 and December 2009, 115 patients who underwent SBRT and 65 SLR were eligible for inclusion in the study. The patient characteristics are shown in Table 1. The clinical stage of T and N was determined with FDG-PET and CT in 56 SBRT patients, and 39 individuals who underwent SLR. Data regarding FEV1 were not available in 13 SBRT patients. NSCLC malignant histology was confirmed using pre-treatment cytology or biopsy in all SBRT and 21 SLR patients, and using intraoperative
Discussion
Limited data are available comparing the survival of patients who underwent SBRT or SLR for stage I NSCLC. Grills et al. compared the outcome after SBRT or wedge resection in 124 patients [27]. With a median potential follow-up of 2.5 years, OS was higher after wedge resection, but cause-specific survival (CSS) was identical. Parashar et al. reported no significant difference in local control, DM, OS or toxicity between 47 patients who underwent SBRT or SLR followed by radioactive seed
Conflict of interest statement
Y.M. and M.H. receive a grant from a Japan Society for the Promotion of Science Grant-in-Aid for Scientific Research. M.H. has a consultancy agreement with Mitsubishi Heavy Industries Ltd., Japan.
Acknowledgement
This study was partially supported by a Japan Society for the Promotion of Science Grant-in-Aid for Scientific Research (A) 25253078. The grant had no role in the study design, conduct of the study, data collection, data interpretation or preparation of the report.
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2021, International Journal of Radiation Oncology Biology PhysicsCitation Excerpt :These metrics are not routinely reported in the SBRT literature. Further, patients undergoing SBRT for early-stage NSCLC generally have greater competing risks for death from causes other than their lung cancer compared with patients undergoing surgery because the latter have fewer competing comorbidities.26,27 Thus, it is possible that reported actuarial LC rates at 1 to 3 years after SBRT overestimate the true LC.