Prognostic significance of examined lymph node count in older patients with stage T1N0M0 pulmonary carcinoid tumours: a population-based propensity score-matched analysis.

BACKGROUND: The optimal number of examined lymph nodes (ELNs) for older early-stage pulmonary carcinoid tumour (PC) patients is unknown. AIMS: To explore the prognostic effect of the ELN count in older patients with stage T1N0M0 PC resection. METHODS: Clinical data from the Surveillance, Epidemiology, and End Results database on stage T1N0M0 PC older patients (age ≥ 65 years) who underwent sublobar resection and lobectomy between 2000 and 2018 were retrospectively analysed for two ELNs-stratified (≥ 7 vs. < 7 ELNs) propensity score-matched (PSM) groups. Overall survival (OS) was calculated and compared with Kaplan-Meier analysis and log-rank test, respectively, and the independent prognostic factors were estimated using a Cox proportional hazard model. RESULTS: Among 1077 participants (median dissected LN 4; mean ELNs 6.19 ± 7.04), 393 (36.49%) in the ≥ 7 ELNs group had better 5- and 10-year OS than the < 7 ELNs group (before PSM: 5-year OS = 93.01 vs. 85.22%, 10-year OS = 72.38 vs. 58.99%, p < 0.001; after PSM: 5-year OS = 93.12 vs. 85.97%, 10-year OS = 75.25 vs. 60.03%, p = 0.001). Subgroup analysis stratified by histologic type and surgical method showed a similar survival trend. Age-stratified analysis showed that, compared with the < 7 ELNs group, the ≥ 7 ELNs group had better 5- and 10-year OS but only better 5-year OS in participants > 75 years. Compared with the < 7 ELNs group, subgroup analysis by tumour size showed superior OS with 1.1-3.0 cm tumours in the ≥ 7 ELNs group, but no significant intergroup difference with tumours < 1.0 cm. Multivariate Cox analysis showed ≥ 7 ELNs was associated with improved OS. CONCLUSION: Higher ELNs correlated with increased long-term survival in older early­stage PC patients, and a minimum of 7 ELNs are recommended for prognostication in these patients (especially those aged 65-75 years, with tumour size 1.1-3.0 cm).

Does Examined Lymph Node Count Influence Survival in Surgically Resected Early­stage Pulmonary Typical Carcinoid Tumors?

OBJECTIVES: We aimed to evaluate the prognostic impact of the number of examined lymph nodes (ELNs) in resected early­stage pulmonary typical carcinoid tumors (TC). METHODS: Patients who underwent sublobar resection and lobectomy for stage T1N0M0 TC between 2004 and 2016 were identified from the Surveillance, Epidemiology, and End Results database and enrolled in the ELNs≥4 or ELNs<4 groups (optimal cutoff using X-tile). Propensity score matching balanced baseline intergroup characteristics. Kaplan-Meier curve and log-rank test were used to calculate and compare overall survival (OS) rates. Cox proportional hazard model analysis was used to identify independent prognostic factors. RESULTS: Among 2234 participants, 961 (43.02%) and 1273 (56.98%) had ELNs <4 and ≥4, respectively. The 5-year OS was significantly higher in the ELNs≥4, compared with ELNs<4, group, both before and after propensity score matching (95.41% vs. 89.71%, P<0.001 and 95.24% vs. 90.28%, P=0.004), respectively. Surgical subgroup analysis confirmed this survival trend in the lobectomy and sublobar resection groups. Tumor size-based subgroup analysis revealed superior OS with ELNs≥4 than ELNs<4 for tumors measuring 1.1-3.0 cm but not for tumors <1.0 cm. Multivariate Cox analysis showed that ELN≥4 contributed to improved OS. CONCLUSIONS: The higher the ELNs, the greater the long-term survival rate in patients with early­stage TC. Therefore, we recommend at least 4 ELNs as the cutoff value for evaluating the prognosis of early­stage TCs, especially for patients with a tumor size of 1.1 to 3.0 cm.