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Clinical characteristics and advantages of primary peripheral micro-sized lung adenocarcinoma over small-sized lung
Wang-Yu Zhu1, Lin-Lin Tan2, Zhao-Yu Wang3
1Department of Cardio-Thoracic Surgery, Zhoushan Hospital, Zhoushan, Zhejiang Province, China Lung Cancer Research Center, Zhoushan Hospital, Zhoushan, Zhejiang Province, China Cell and Molecular Biology Laboratory, Zhoushan Hospital, Zhoushan, Zhejiang Province, China.
Objectives:
Micro-sized lung adenocarcinoma with a tumour of 1.0 cm or less could help identify the patients who would undergo the surgery treatment with limited resection; however, its clinical characteristics and survival rates remain unclear and are to be tested further.
Methods:
Histology, lymphatic metastasis, surgical procedure and survival rates of 366 lung adenocarcinoma patients (from January 2007 to December 2013) with a tumour of 2.0 cm or less were analysed retrospectively. Among these patients, 175 had a primary tumour with a diameter of 1.0 cm or less and 191 had a tumour of 1.1-2.0 cm. The survival of 366 patients was evaluated by the restricted mean survival time (RMST) test, and the risk factors were assessed by multivariable analysis.
Results:
Larger lesion had a significant relation to old age, male sex, preoperatively carcinoembryonic antigen (CEA) positive, invasive adenocarcinoma (IAC) and advanced-stage disease (P < 0.0001, P = 0.001, P = 0.001, P < 0.0001 and P < 0.0001, respectively). Patients with adenocarcinoma in situ (AIS)/minimally invasive adenocarcinoma obtained a better prognosis than those with IAC (5-year overall survival rate: 98.5 vs 84.3%, P = 0.001; disease-related survival rate: 98.5 versus 85.2%, P = 0.001). The 5-year overall survival rates of patients with a tumour less than 1.0 cm in comparison with 1.1-2.0 cm were 100.0 and 88.4% (P < 0.001), whereas the 5-year lung adenocarcinoma-specific survival rates were 100.0 and 89.0% (P < 0.001), respectively. Multivariable analysis for prognosis of lung adenocarcinoma patients with a tumour 2.0 cm or less in diameter revealed that histology, lymphatic metastasis and advanced pathological stage affected the 5-year overall and disease-related survival rates unfavourably (P < 0.0001, 0.002, 0.001; and P < 0.0001, 0.005, 0.001, respectively), whereas tumour size did not have an obvious influence on survival.
Conclusions:
Micro-sized lung adenocarcinoma (1.0 cm or less) had specific clinical characteristics and more favourable survival rates. These tumours and a subtype of AIS evaluated by computed tomography images or intraoperative frozen section may be appropriate candidates for a limited resection without mediastinal lymph node dissection.
Insights
Micro-sized lung adenocarcinoma (≤1.0 cm) shows favorable survival rates, suggesting suitability for limited resection. Further research is needed to clarify clinical characteristics and survival outcomes for these small tumors.
Area of Science:
- Oncology
- Thoracic Surgery
- Pathology
Background:
- Lung adenocarcinoma (LUAD) presents diagnostic challenges, particularly for small tumors.
- Identifying patients eligible for limited resection is crucial for optimizing treatment outcomes.
- Clinical characteristics and survival data for micro-sized LUAD (≤1.0 cm) require further elucidation.
Purpose of the Study:
- To investigate the clinical characteristics and survival rates of micro-sized lung adenocarcinoma (≤1.0 cm).
- To compare outcomes between LUAD patients with tumors ≤1.0 cm versus those with tumors 1.1-2.0 cm.
- To assess the suitability of micro-sized LUAD for limited resection strategies.
Main Methods:
- Retrospective analysis of 366 LUAD patients with tumors ≤2.0 cm diagnosed between 2007-2013.
- Categorization into two groups: primary tumor diameter ≤1.0 cm (n=175) and 1.1-2.0 cm (n=191).
- Survival analysis using restricted mean survival time (RMST) and multivariable risk factor assessment.
Main Results:
- Tumor size ≤1.0 cm was associated with significantly better 5-year overall survival (100.0% vs 88.4%) and disease-specific survival (100.0% vs 89.0%) compared to tumors 1.1-2.0 cm (P < 0.001).
- Adenocarcinoma in situ (AIS)/minimally invasive adenocarcinoma (MIA) demonstrated superior prognosis over invasive adenocarcinoma (IAC).
- Multivariable analysis identified histology, lymphatic metastasis, and advanced pathological stage as unfavorable prognostic factors, while tumor size did not significantly influence survival in tumors ≤2.0 cm.
Conclusions:
- Micro-sized lung adenocarcinoma (≤1.0 cm) exhibits distinct clinical features and superior survival rates.
- These small tumors, along with certain AIS subtypes identifiable via CT or intraoperative frozen section, are potential candidates for limited resection without mediastinal lymph node dissection.
