|Year : 2022 | Volume
| Issue : 2 | Page : 399-404
A study of microwave ablation for small cell lung cancer
Jiao Wang1, Likuan Hu2, Xia Yang3, Xin Ye4, Yang Ni5, Min Meng3, Guanghui Huang3, Tiehong Zhang3, Wenhong Li3, Xiaoying Han3, Zhigang Wei4, Jianjian Dai3, Zhigeng Zou3
1 Department of Oncology, Shandong Provincial Hospital, Cheeloo College of Medicine, Shandong University, Jinan, China
2 Department of Radiation Oncology, Qilu Hospital, Cheeloo College of Medicine, Shandong University, Jinan, China
3 Department of Oncology, Shandong Provincial Hospital Affiliated to Shandong First Medical University, Jinan, China
4 Department of Oncology, Shandong Lung Cancer Institute, Shandong Provincial Qianfoshan Hospital, The First Affiliated Hospital of Shandong First Medical University, Jinan, China
5 Department of Oncology, Shandong Provincial Hospital, Cheeloo College of Medicine, Shandong University; Department of Oncology, Shandong Provincial Hospital Affiliated to Shandong First Medical University, Jinan, China
|Date of Submission||31-Oct-2021|
|Date of Acceptance||30-Nov-2021|
|Date of Web Publication||20-May-2022|
Department of Radiation Oncology, Qilu Hospital, Cheeloo College of Medicine, Shandong University, Jinan
Department of Oncology, Shandong Provincial Hospital Affiliated to Shandong First Medical University, Jinan
Department of Oncology, Shandong Lung Cancer Institute, Shandong Provincial Qianfoshan Hospital, The First Affiliated Hospital of Shandong First Medical University, Jinan
Source of Support: None, Conflict of Interest: None
Purpose: To reveal the survival and safety of percutaneous microwave ablation (MWA) combined with chemoradiotherapy (CRT) in treating small cell lung cancer (SCLC).
Materials and Methods: Clinical data of 48 SCLC patients who underwent MWA were retrospectively collected; survival and incidence of major complications were analyzed.
Results: Totally, 48 SCLC patients underwent 51 MWA procedures. The median overall survival (OS) for all SCLC was 27.0 months (95% confidence interval 22.4–31.6 months). The OS of limited-stage (LS-SCLC) was longer than the extensive-stage (ES-SCLC) (median 48.0 months vs. 25.0 months, P = 0.022). The OS of SCLC with tumor diameter ≤3.0 cm was longer than that of tumor diameter >3.0 cm (median 48.0 months vs. 27.0 months, P = 0.041). For LS-SCLC, the 1-, 2-, 3-, and 5-year survival rate was 91.67%, 72.22%, 66.67%, and 61.11%, respectively. For ES-SCLC, the 1-, 2-, and 3-year survival rates were 83.33%, 50.0%, and 8.33%. Major complications included pneumothorax needing tube placement (29.4%), rarely arrhythmia (2.0%), empyema (2.0%), pulmonary fungal infection (2.0%), and shingles (2.0%).
Conclusion: For SCLC patients, who received MWA combined with CRT, OS of LS-SCLC and tumor diameter ≤3.0 cm was better than that of the ES-SCLC and tumor diameter >3.0 cm. For inoperable SCLC, MWA was safe.
Keywords: Complication, extensive-stage, limited-stage, overall survival, percutaneous microwave ablation, small cell lung cancer
|How to cite this article:|
Wang J, Hu L, Yang X, Ye X, Ni Y, Meng M, Huang G, Zhang T, Li W, Han X, Wei Z, Dai J, Zou Z. A study of microwave ablation for small cell lung cancer. J Can Res Ther 2022;18:399-404
|How to cite this URL:|
Wang J, Hu L, Yang X, Ye X, Ni Y, Meng M, Huang G, Zhang T, Li W, Han X, Wei Z, Dai J, Zou Z. A study of microwave ablation for small cell lung cancer. J Can Res Ther [serial online] 2022 [cited 2022 Oct 1];18:399-404. Available from: https://www.cancerjournal.net/text.asp?2022/18/2/399/345535
| > Introduction|| |
Small cell lung cancer (SCLC) has neuroendocrine features and accounts for about 15% of all lung cancers. It is insidious, and about 66.7% of SCLC patients are already in the extensive stage (ES) at the time of diagnosis. It rapidly progresses and is prone to metastasis, recurrence, and drug resistance, resulting in a high mortality rate. The EP (etoposide and cisplatin or carboplatin) chemotherapy regimen and radiotherapy have always been recommended for SCLC; however, the survival benefit is unclear. After a comprehensive treatment of SCLC using surgery, radiotherapy, and chemotherapy, the overall efficacy is poor. Of limited-stage SCLC (LS-SCLC), the median overall survival (OS) is 15–20 months, and the 2-year survival rate is 20%~40%, while in the extensive-stage SCLC (ES-SCLC), the median OS is 8–13 months and the 2-year survival rate is around 5%.,,, Therefore, it is imperative to develop novel treatment strategies for SCLC.
MWA of lung cancer is a precise and minimally invasive treatment technology that uses the biological effects of heat to cause direct, irreversible damage, or coagulative necrosis of tumor cells. There have been several studies on MWA in treating non-NSCLC and lung metastases, and encouraging results have been achieved accordingly.,,,
Some retrospective studies have been conducted on radiofrequency ablation (RFA) or microwave ablation (MWA) in SCLC owing to a small sample or short follow-up.,, In this study, the survival and safety of MWA combined with chemoradiotherapy (CRT) were revealed in SCLC treatment.
| > Materials and Methods|| |
This study was approved by the Institutional Review Board of Shandong Provincial Hospital affiliated with Shandong University, and written informed consent of all participants was obtained. Before enrollment, all patients underwent rigorous staging examinations, including enhanced chest and upper abdomen computed tomography (CT), cranial magnetic resonance imaging, and a bone scan. If LS-SCLC was considered, positron emission tomography/CT (PET/CT) was used for further validation, and a pathological diagnosis of the tumor was needed.
The clinical data of 48 SCLC patients who underwent MWA between April 2011 and July 2019 at the Department of Oncology, Shandong Provincial Hospital affiliated to Shandong University were collected [Table 1].
Microwave ablation treatment inclusion criteria
- Eastern Cooperative Oncology Group, score ≤2
- First MWA: LS-SCLC with no surgical indications or after at least two cycles of first-line chemotherapy regimen of EP (with or without chest radiotherapy), superior vena cava syndrome controlled. ES-SCLC with metastatic symptoms controlled through CRT (brain metastasis et al.)
- Re-MWA: The primary lesion progressed after first MWA with no other new lesions, or other lesions well controlled.
Microwave ablation procedure
All patients underwent rigorous staging examinations at the time of diagnosis. Oncological surgeons, oncologists, endoscopy physicians, diagnostic radiologists, clinical pharmacists, anesthesiologists, imaging intervention physicians, respiratory and critical care physicians, pathologists, and interventional radiologists formulated and implemented a multidisciplinary treatment model throughout the whole treatment process.
The equipment, materials, preoperative preparation, development of MWA treatment plan, operation procedure, operation methods, and precautions for MWA were followed as previously described. Imaging success was evaluated using the modified solid tumor efficacy evaluation criteria (mRECIST) [Figure 1].
|Figure 1: Efficacy evaluation through imaging. (a and b) Primary tumor; (c and d) 6 months after ablation|
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Data collection and statistical analysis
OS was calculated from the beginning of SCLC to the date of death or the last follow-up. The Kaplan–Meier analysis was used for survival comparisons. Univariate and multivariate Cox regression analysis was used for prognostic factors and the hazard ratios (HR) for factors with 95% confidence intervals (CI). Differences with a two-sided P < 0.05 were considered statistically significant. SPSS Statistics for Windows Version 26.0 (IBM, Chicago, IL, USA) were used for statistical analysis.
| > Results|| |
In total, 48 patients underwent MWA, of which three patients underwent re-MWA due to incomplete ablation or local recurrence [patients' features in [Table 1]]. Of these 48 SCLC patients, 35 (72.9%) patients conducted 38 MWA procedures. Tumor diameter ≤3.0-cm included 23 (76.7%) LS-SCLC patients and seven (23.3%) ES-SCLC patients. The primary tumor was dominant in the right lower lobe (n = 14, 29.2%), with 11 of LS-SCLC and three of ES-SCLC. In LS-SCLC patients, 21 (60.0%) had lymph nodes, and only eight (22.9%) received radiotherapy before MWA. In ES-SCLC patients, the metastasis organ was the liver (n = 2, 15.4%), lung (n = 3, 23.1%), brain (n = 2, 15.4%), kidney (n = 2, 15.4%), and adrenal gland (n = 2, 15.4%).
Outcomes after microwave ablation
The follow-up period was 4–81 months. The median OS of all SCLC was 27.0 months (95% CI, 22.4–31.6 months), while LS-SCLC (median OS = 48.0 months) with inestimable 95% CI and ES-SCLC (25.0 months, 95% CI, 19.7–30.3 months) [Figure 2].
|Figure 2: Kaplan–Meier survival curves for small cell lung cancer (SCLC) and LS-SCLC that received microwave ablation and chemo radiotherapy. (a) The estimated overall survival (OS) rates of all patients were 89.58% at 1 year and 66.67% at 2, 52.08% at 3 years, and 47.92% at 4 and 5 years. (b) In limited-stage patients, the estimated OS rates were 91.67% at 1 year, 72.22% at 2 years, 66.67% at 3 years, and 61.11% at 4 and 5 years. (c) In extensive-stage patients, the estimated OS rates were 83.33% at 1 year, 50.0% at 2 years, and 8.33% at 3 years|
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The estimated OS rates of all patients were 89.58% at 1 year, 66.67% at 2 years, 52.08% at 3 years, and 47.92% at 4 and 5 years. In limited-stage patients, the estimated OS rates were 91.67% at 1 year, 72.22% at 2 years, 66.67% at 3 years, and 61.11% at 4 and 5 years. In extensive-stage patients, the estimated OS rates were 83.33% at 1 year, 50.0% at 2 years, and 8.33% at 3 years.
Survival and prognostic factors
LS-SCLC had longer OS than ES-SCLC (median 48.0 months vs. 25.0 months, P = 0.022). SCLC with tumor diameter ≤3.0 cm (n = 30, 62.5%) had a median OS of 48.0 months (95% CI 13.9–82.1 months), and those with tumor diameter >3.0 cm (n = 18, 37.5%) had a median OS of 27.0 months (95% CI 22.4–31.6 months), the difference between the two subgroups was statistically significant (P = 0.041), while nonstatistically significant in diameter subgroups of LS-SCLC (P = 0.062) [Figure 3]. Other factors, such as age, gender, radiotherapy before MWA, and lymph nodes are insignificantly associated with survival. Multivariate Cox regression analysis indicated that stage was a significant predictor of OS (HR 0.38, 95% CI, 0.16–0.90, P = 0.03) [Table 2].
|Figure 3: Kaplan–Meier analysis of overall survival (OS) by stage and tumor diameter involvement. (a) The OS of limited-stage small cell lung cancer (LS-SCLC) is longer than that of extensive-stage-SCLC (P = 0.022). (b) The OS of SCLC with tumor diameter ≤3.0 cm is longer than that of > 3.0 cm (P = 0.041). (c) The OS of LS-SCLC with tumor diameter ≤3.0 cm is no longer than that of >3.0 cm (P = 0.062)|
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Major complications were staged according to the criteria established by the American Society of Interventional Radiology. No deaths occurred during the procedure or within 1 month after MWA. Adverse reactions and minor complications, such as pain, postablation syndrome, asymptomatic pleural effusion, asymptomatic pleural effusion on imaging, subcutaneous emphysema, and blood in sputum were generally self-limiting and did not need hospitalization for observation. Major complications requiring hospitalization included pneumothorax requiring drainage tube placement (15/51, 29.4%) and rarely arrhythmia (1/51, 2.0%), empyema (1/51, 2.0%), pulmonary fungal infection (1/51, 2.0%), and shingles (1/51, 2.0%). Pneumothorax requiring drainage tube placement appeared immediately after surgery in most cases (9/15, 60%), and the remaining cases (6/15, 40%) were discovered on chest CT reexamination 24–36 h after MWA. In addition, most cases required hospitalization for over 48 h for observation (12/15, 80%). Arrhythmia (n = 1, 2.0%) appeared during the MWA procedure, cured within 24 h. Lung abscess (n = 1, 2.0%) occurred 2 months after MWA, relieved after thoracic drainage tube placement. Pulmonary fungal infection post-MWA (n = 1, 2.0%) was confirmed to be an Aspergillus fumigatus infection. Shingles on the contralateral skin (n = 1, 2.0%) developed after MWA. Except for the case of shingles that caused long-term skin lesions, all complications were cured after treatment [Table 3].
| > Discussion|| |
Numerous studies have indicated that MWA affects the treatment of peripheral NSCLC. MWA applied for SCLC is currently controversial. Retrospective studies on RFA or MWA for SCLC patients have rarely been seen. Huang et al., conducted RFA (simultaneous RFA and needle biopsy) on 49 patients with SCLC, 52 lesions, and conducted long-term follow-up for 11 years. The 1-, 2-, 3-, 5-, and 10-year survival rates were 89.4%, 67.5%, 39.1%, 16.5%, and 0%, respectively. The median OS was 32 months (95% CI, 25.7–38.2 months). Tumor diameter (<3-cm or ≥3-cm) was not a predictor of OS. Aaron W. P. Maxwell et al. conducted RFA and MWA, respectively, for nine patients with SCLC according to the surgeon's preference, including five patients with MWA and four patients with RFA, and the patients were divided into the limited stage group (no lymph node metastasis) and ES group. The median follow-up time was 16.0 months (range, 2–48 months). The median OS and 1-year survival rate in the limited stage group were better than those in the ES group (47.0 months vs. 5.5 months, 3 [100%] vs. 2 [40%]). In all, five patients developed pneumothorax, three underwent outpatient thoracic catheterization, no patients were hospitalized, and no patient developed serious complications. Song et al. reported a case of an 85-year-old male diagnosed with SCLC. The patient refused radiotherapy and chemotherapy and agreed to undergo RFA, which was in a limited stage (no lymph node metastasis) and peripheral. The efficacy was evaluated as a partial response (PR) after 2 years of follow-up. In our study, the median OS of LS-SCLC and ES-SCLC (48.0 and 25.0 months) were both longer than those previous studies; MWA is effective as a maintenance treatment and local treatment after progression of the primary tumor.
The major complications are observed to be tolerated. Previous studies exhibited the incidence of pneumothorax after ablation of lung cancer is 11%–52%, of which 6%–29% required chest tube placement for drainage.,,,,, In our study, pneumothorax needing drainage tube placement accounted for 15% of all procedures, comparable to previous outcomes above.
However, our study has limitations. First, a control study is needed to distinguish whether MWA prolonged OS for SCLC. Second, the LS-SCLC patients were in the majority; the ratio of LS-SCLC to ES-SCLC was wide.
Our study involved the highest number of SCLC cases for MWA combined with CRT. MWA is safe, and patients can tolerate follow-up chemotherapy and radiotherapy after MWA. In the future, larger scale, multicenter, prospective, and control studies are needed to evaluate the role of MWA in SCLC.
| > Conclusion|| |
MWA combined with CRT is safe and can be a good maintenance treatment for limited-stage and extensive-stage SCLC.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2], [Figure 3]
[Table 1], [Table 2], [Table 3]