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Page 4 of 12 Galvez et al. Mini-invasive Surg 2020;4:86 I http://dx.doi.org/10.20517/2574-1225.2020.86
[30]
-CALGB- 140503) where 692 people are expected to be recruited . These two studies will probably clear
some of the actual controversy and might set the indications for SLR in early stage NSCLC.

Studies comparing different approaches for sublobar resections have shown a shorter length of chest tube,
shorter hospital stay, and less postoperative pulmonary complications in video-assisted thoracic surgery
sublobar anatomical resections when compared to open thoracotomy [26,31-33] .

We must differentiate between two groups. The first group includes high-risk patients (FEV1 < 50%,
diffusion capacity for carbon monoxide -DLCO < 50%) or combination of advanced age, impaired
[34]
pulmonary function, pulmonary hypertension, or decreased left ventricle function , where SLR and SABR
are potential alternative therapeutic options to standard lobectomy. The second group includes elective
intentional SLR in a specific subset of stage I NSCLC when compared to SABR.

COMPARISON OF SUBLOBAR RESECTION AND SABR IN NSCLC
Sublobar resection and SABR in high-risk or medically inoperable patients
There are very few studies that specifically address the results of sublobar resections compared to SABR
in high-risk operable or medically inoperable lung cancer patients [Table 1]. When we consider this
comparison, not only should oncological outcomes in terms of overall survival or loco-regional control
be addressed, but also postoperative morbidity and mortality, patient’s quality of life during and after
[41]
treatment administration, and ability to deliver therapy (especially for SABR) .

There are important factors that make these studies difficult that must be mentioned. First, the definition
of local recurrence is usually different in surgical series than in SABR studies. Surgical series usually define
local recurrence as recurrence in the staple line, in the chest wall, in the same lobe, or in the hilar or even
mediastinal lymph nodes. On the other hand, SABR series define local recurrence only as recurrence in
[41]
the primary tumor site . Second, patient population should be similar in both arms, because most SABR
series have address only inoperable and high-risk operable patients who can die due to their comorbidities
before a recurrence appears, while SLR have usually included both standard-risk and high risk operable
patients. Third, adverse events should be homogenized because the chronological pattern of adverse events
is different between these two therapeutic alternatives. While adverse events usually occur early in surgical
patients, adverse events usually appear later in SABR patients. Fourth, in SABR patients, surgical nodal
[35]
staging is usually not performed, especially when dealing with stage I tumors less than 2 cm in diameter ,
so lymph node assessment is limited to pretreatment imaging studies (e.g., chest CT and PET scan).

Yendamuri et al. , in 2007, retrospectively analyzed 160 clinical stage I NSCLC patients with
[36]
contraindication for lobectomy (68 wedge resection and 92 3D conformal radiation therapy). They found a
trend to better outcomes with limited resection with OS (P = 0.010) and recurrence-free survival (RFS) (P
= 0.000) in the univariate analysis; however, that trend was only observed to be significant in the RFS in the
multivariate analysis (P = 0.002). After a propensity matching score analysis, these differences in OS and
RFS disappeared between both groups, so they concluded that both treatments were comparable.

[42]
In 2013, Mahmood et al. performed a Best Evidence Topic analysis comparing SABR with SLR in clinical
stage I high-risk NSCLC patients. They only included 3 comparative studies. The first one found higher
[37]
mean survival (4.1 years vs. 2.9 years) in the SLR group, and higher 4-year survival (51.3% vs. 30.1%). The
second, Grills et al. , reported higher rate of local recurrence with wedge resection compared to SABR (20%
[38]
vs. 4%). OS was higher after wedge resection (87% vs. 72%; P = 0.01), but cause-specific survival showed
no differences (94% vs. 93%; P = 0.53). In the third, Forquer et al. found no differences in 3-year survival
[39]
were found, but they found higher median survival in SLR compared to SABR (55 months vs. 37 months),
although no differences in cancer specific survival were observed. Dr. Scanagatta commented the
[43]