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Dolan et al. Mini-invasive Surg 2021;5:3 I http://dx.doi.org/10.20517/2574-1225.2020.101 Page 3 of 8
[2]
Lastly, Puri et al.’s sub-analysis of their high-risk patients who underwent sublobar resection found no
differences in perioperative outcomes be tween high-risk patients (n = 72) and normal-risk patients (n =
112). Atrial fibrillation was slightly more common in the high-risk group than normal-risk, 11% (8/72) vs.
6% (7/112), P = 0.28, but this was potentially due to low event rates in both groups. They did not report
the sublobar resection group survival Kaplan-Meier curves, but noted on logistic regression analysis that
ACOSOG Z4032 high-risk status was not associated with the risk of perioperative complications (data not
[1,2]
provided in their manuscript) .
THERAPEUTIC CHOICE FOR OPTIMAL LONG-TERM OUTCOMES OF HIGH-RISK PATIENTS
[7]
Since Ginsberg et al.’s 1995 report on the Lung Cancer Study Group’s randomized control trial of
lobectomy vs. limited resection for T1 NSCLC, lobectomy has remained the gold standard for resection of
early stage lung cancer. However, the current NCCN guidelines state that anatomic pulmonary resection
is the preferred method for the majority of patients with NSCLC . The NCCN guidelines further
[3,7]
elaborate on sublobar resection as being appropriate in the setting of “poor pulmonary reserve or other
major comorbidity that contraindicates lobectomy”, while noting that SBRT is recommended for medically
[3]
inoperable patients or patients who refuse surgery . As there is no clear definition for “high-risk” patients,
the choice of therapy for high-risk patients remains the purview of the clinicians treating the patient.
Ablation techniques, SBRT, and lobectomy continue to be options for high-risk patients, in addition to
sublobar resection.

Multiple ablation techniques have been reported for lung cancer including RFA, microwave ablation, and
[8]
cryoablation [8-10] . In 2005, Fernando et al. reported RFA as an alternative for patients with peripheral lung
cancer who are not surgical candidates. In their initial 18 patient series with 21 total tumors, they treated
patients of all stages with a median tumor size of 1.8 cm (range 1.2-4.5 cm). In this broad patient set, they
noted a mean progression-free survival of 16.8 months. In 2007, Simon et al. published their 153 patient
[11]
series from 1998-2005 that reviewed the outcomes of patients treated with RFA who were refused surgery
or were not deemed suitable as surgical candidates. The 5-year survival rate for stage I NSCLC was 27%,
with local progression-free rate for tumors ≤ 3 cm equal to 47%, and for > 3 cm equal to 25%. A recent
review of the National Cancer Database compared SBRT to RFA for stage I NSCLC (4,454 SBRT vs. 335
[12]
RFA patients) . RFA patients were noted to have more comorbidities than SBRT patients. They performed
a propensity score matching and found no difference in the overall survival rate (OS) at 1-, 3-, and 5- years
(31.9% SBRT vs. 27.1% RFA, P = 0.835).

[9]
[9]
MWA is another thermal ablation technique that uses high temperature to destroy tumors . Zhong et al.
reported on 113 patients who underwent microwave ablation; 35 patients had early stage disease and 78
patients had late stage lung cancer. 10.6% (12/133) of all patients had a pneumothorax after the procedure,
but no intraoperative or perioperative deaths were observed. At 3 years, they reported that the survival
of the early stage group was 84.7%, in comparison to 71.7% in the advanced stage group, P = 0.576. Zhao
et al. reported a longer-term follow-up (out to 5 years) of 34 early stage patients (T1a-T3N0M0).
[13]
Pneumothorax was noted in 24 cases (59%) with 6 cases requiring chest tube insertion (15%). Their
[14]
5-year overall survival rate was 46.7%. Yuan et al. performed a meta-analysis of 53 studies to compare
outcomes of RFA with MWA for primary lung cancer and pulmonary metastases. They found a pooled
pneumothorax rate of 34.3% (95%CI: 25.9%-43.1%) in the RFA group vs. 33.9% (95%CI: 23.8%-44.8%) in
the MWA group, P = 0.957. Severe pneumothorax that required intervention occurred in 12.3% of patients
(95%CI: 6.8%-19.1%) in the RFA group and in 11.0% of patients (95%CI: 4.5%-19.7%) in the MWA group, P
= 0.797. Based on the 8 studies for RFA and 6 studies for MWA, they found comparable median OS for the
2 groups, RFA 28.4 months (95%CI: 20.9-35.8) vs. MWA 24.4 months (95%CI: 16.9-31.8).