Effect of Ki-67 proliferation index on survival in large cell neuroendocrine carcinoma of the lung.

Objective: Large cell neuroendocrine carcinoma of the lung is a rare type of lung cancer. There is a limited number of studies on clinical and histopathological characteristics that are effective in survival. The aim of this study was to investigate the relationship between histopathological and clinical characteristics, mainly Ki-67 proliferation index, and survival in patients diagnosed with large cell neuroendocrine carcinoma of the lung.

Methods: The data of 38 patients followed up with the diagnosis of large cell neuroendocrine carcinoma of the lung were evaluated. The mean Ki-67 value was determined to be 65.8% (±20.8). The patients' clinical characteristics and survival times were compared according to the cut-off value determined for Ki-67 index.

Results: When median overall survival times were compared, it was seen that overall survival was numerically lower in patients aged 65 years and over, in tumors located on the right side, in cases who were in the metastatic stage at diagnosis, whose Ki-67 index was 65% and above, who did not receive chemotherapy, who did not undergo curative surgery, and in patients with chronic diseases (p>0.05). In the Kaplan-Meier analysis, the median overall survival was determined to be 22.2 months (95%CI 21.7-22.7) in the patients with Ki-67<65%, while it was found to be 20.3 months (95%CI 4.5-36.2) in the patients with Ki-67≥65% (p=0.351).

Conclusion: Our study identified subgroups with decreased survival in large cell neuroendocrine carcinoma of lung patients. Studies including a larger number of patients are needed to identify the prognostic importance of these clinical and histopathological characteristics.