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Page 6 of 12 Galvez et al. Mini-invasive Surg 2020;4:86 I http://dx.doi.org/10.20517/2574-1225.2020.86

Tamura et al. [35] (2019) 247 stage I NSCLC with medical 5-year RFS: SLR showed better RFS, with this
(Japan) comorbidities: - SLR 69.7% difference significant in tumors >
Retrospective observational - 141 SLR (41 segmentectomies - SBRT 50.2% (P = 0.036) 2 cm in diameter. SBRT showed
study (level 3) and 100 wedge) 5-year OS higher recurrence rate
- 106 SBRT - SLR 75.2%
- SBRT 70.2% (P = 0.40)
Disease-specific survival (DSS)
- SLR 89.5%
- SBRT 76.0% (P = 0.78).
5-year RFS in > 2 cm:
- SLR 69%
- SBRT 32% (P = 0.042)
Disease-specific survival (DSS) in
> 2 cm
- SLR 85.4%
- SBRT 48.5% (P = 0.064).
In < 2 cm: no differences in OS (P
= 0.81), RFS (P = 0.39), DSS (P =
0.89)
5-year RFS in outer tumors:
- SLR 72.1%
- SBRT 42.2% (P = 0.002)

NSCLC: non-small cell lung cancer; OS: overall survival; RFS: recurrence-free survival; SLR: sublobar resection; SABR: stereotactic
ablative radiotherapy; SBRT: stereotactic body radiation therapy; DSS: disease-specific survival; CSS: cancer-specific survival; DFS:
disease-free survival

potential benefit of the CyberKnife technology applied to SABR for these patients because it has a
synchrony system for the respiratory movements with an accuracy of 2 mm or less, that might decrease
collateral damage to surrounding parenchyma, as a potential issues for research.

[16]
Varlotto et al. reported, in 2013 from cancer databases, 48 SLR and 137 SABR patients with a median
follow-up of 2.2 years. OS was superior in SLR compared with SABR matched pairs (86.3% and 31.7%
for SLR and SABR at 5 years, respectively, P = 0.003). However, the multivariate analysis that included
propensity scores as a covariate showed that the hazard ratio for OS was not significant, so no significant
differences between both treatments could be drawn.

A retrospective analysis performed by Matsuo et al. , in 2014, included patients with clinical stage I
[40]
NSCLC at high-risk for lobectomy who underwent either SABR or SLR. After a propensity matching score
analysis, there was no statistically significant difference in 5-year OS between both treatments (40.4% vs.
55.6%; P = 0.124).

[9]
Ackerson et al. , in 2018, retrospectively compared 151 SLR (105 wedge and 46 segmentectomies) in
clinical stage I patients not amenable to lobectomy, with 70 patients treated with SABR (89% deemed
medically inoperable by surgeons due to severe decrease in pulmonary function or severe cardiovascular
disease). Radiotherapy patients were older (P = 0.019), had higher Charlson comorbidity index score (P <
0.001), had lower pulmonary function in terms of FEV1 and DLCO (P = 0.001 and P < 0.001, respectively),
and larger tumors (P < 0.001), making comparison problematic. OS and DFS were superior in the surgical
group (3-year OS 63% vs. 35%, P < 0.001; 3-year DFS 42% vs. 29%, P = 0.004), but there were no differences
in cancer-specific disease-free survival (P = 0.84). After adjusting for imbalances in baseline characteristics
of both groups, there was no difference in overall survival between surgery and SABR (HR = 1.20; 95%CI:
0.74-1.95; P = 0.46). 3-year freedom from local recurrence was similar between both treatments (90% vs.
85%, P = 0.71). In the surgical group, 23% developed postoperative complications, while in the SABR group
there were complications in 17%.

A retrospective study of Tamura et al. , in 2019, compared 106 SABR patients with 141 SLR (100 wedge
[35]
and 41 anatomical segmentectomies) in clinical stage I NSCLC with medical comorbidities (e.g., poor