A guide for managing patients with stage I NSCLC: deciding between lobectomy, segmentectomy, wedge, SBRT and ablation-part 4: systematic review of evidence involving SBRT and ablation

Abstract

Background: Clinical decision-making for patients with stage I lung cancer is complex. It involves multiple options [lobectomy, segmentectomy, wedge, stereotactic body radiotherapy (SBRT), thermal ablation], weighing multiple outcomes (e.g., short-, intermediate-, long-term) and multiple aspects of each (e.g., magnitude of a difference, the degree of confidence in the evidence, and the applicability to the patient and setting at hand). A structure is needed to summarize the relevant evidence for an individual patient and to identify which outcomes have the greatest impact on the decision-making.

Methods: A PubMed systematic review from 2000-2021 of outcomes after SBRT or thermal ablation vs. resection is the focus of this paper. Evidence was abstracted from randomized trials and non-randomized comparisons with at least some adjustment for confounders. The analysis involved careful assessment, including characteristics of patients, settings, residual confounding etc. to expose degrees of uncertainty and applicability to individual patients. Evidence is summarized that provides an at-a-glance overall impression as well as the ability to delve into layers of details of the patients, settings and treatments involved.

Results: Short-term outcomes are meaningfully better after SBRT than resection. SBRT doesn't affect quality-of-life (QOL), on average pulmonary function is not altered, but a minority of patients may experience gradual late toxicity. Adjusted non-randomized comparisons demonstrate a clinically relevant detriment in long-term outcomes after SBRT vs. surgery. The short-term benefits of SBRT over surgery are accentuated with increasing age and compromised patients, but the long-term detriment remains. Ablation is associated with a higher rate of complications than SBRT, but there is little intermediate-term impact on quality-of-life or pulmonary function tests. Adjusted comparisons show a meaningful detriment in long-term outcomes after ablation vs. surgery; there is less difference between ablation and SBRT.

Conclusions: A systematic, comprehensive summary of evidence regarding Stereotactic Body Radiotherapy or thermal ablation vs. resection with attention to aspects of applicability, uncertainty and effect modifiers provides a foundation for a framework for individualized decision-making.

Keywords: Lung cancer; ablation; quality-of-life (QOL); radiotherapy; surgery.

Figure 1

Closed randomized studies of SBRT vs. surgery.
Closed RCTs of SBRT vs. surgery showing the resection extent, tumor size and the type of patients involved, as well as the final accrual. Lobe, lobectomy; Periph, peripheral; SBRT, Stereotactic body radiation therapy.

Figure 2

Ongoing RCTs of SBRT vs. surgery for lung cancer.
Ongoing RCTs of SBRT vs. surgery showing the resection extent, tumor size and the type of patients involved, with accrual targets and anticipated timeline. Lobe, lobectomy; SBRT, Stereotactic body radiation therapy; Seg, segmentectomy; VA, US Veterans Administration Healthcare System.

Figure 3

SBRT vs. lobectomy in patients without comorbidities.
Overall survival in patients with stage cI NSCLC and without comorbidities treated by full-dose SBRT (biologically effective dose of ≥100 Gy) vs. lobectomy. All were surgery-eligible and had a Charlson-Deyo score of 0 (NCDB, 2008-12). (A) Propensity-matched patients and (B) propensity-matched subset who were recommended to have surgery but refused. Reproduced with permission from Rosen et al. (41). SBRT, stereotactic body radiation therapy.

Figure 4

Short-term mortality by age and treatment modality.
Post-treatment 90-day mortality of early stage lung cancer patients by age cohorts; Unadjusted rates and hazard ratio in propensity-matched groups. Data taken from Stokes et al. (5). Lobe, lobectomy; SBRT, stereotactic body radiotherapy; SL, sublobar resection.