Prognostic and predictive importance of proliferation index and neutrophil lymphocyte ratio in stage 2 treatment in small cell lung cancer

Purpose: When lung cancer is divided into two groups as non-small cell lung cancer (NSCLC) and small cell lung cancer (SCLC), 85% is NSCLC and 10-15% is SCLC. Although SCLC is less common than non-small cell subtypes, it has a more aggressive course and is associated with a shorter survival time. In this study, the neutrophil lymphocyte ratio (NLO1) measured at the time of diagnosis, the neutrophil lymphocyte ratio (NLO2) measured before the second-line treatment, the ki-67 proliferation index, the status of receiving curative radiotherapy and the stage at the time of diagnosis of our SCLC patients treated in our clinic, we aimed to reveal its prognostic and predictive importance on progression-free survival (PFS) and overall survival (OS) times. Method: This study included 62 patients over the age of 18, who were diagnosed with SCLC in patients who applied to the Medical Oncology Outpatient Clinic of Dicle University Faculty of Medicine between January 1, 2012 and April 31, 2019 and received outpatient chemotherapy or were hospitalized, and whose data could be accessed retrospectively. The effects of NLR1 measured at the time of diagnosis, NLR2 measured before the second-line treatment and ki-67 on survival were investigated in the patients included in the study. Results: In our study, the data of 62 patients with SCLC were analyzed. 56 (90.3%) of the patients were male and 6 (9.7%) were female. The median (median) age of the patients at the time of diagnosis was 55 years (39-70). As a result of Kaplan-Meier analysis, the median progression-free survival (PFS1) time of the patients was calculated as 7 months and OS time as 14 months. As a result of the statistical analysis, the median NLO1 value was 3.1 and the median NLO2 value was 4.1. These values were accepted as threshold values. While the median PFS1 value of 30 (48%) patients with NLO1 <3.1 was 9 months [95% CI (6.51-11.48)], the median PFS1 value was 5 months [95% CI (4.50-5.49)] in the group with NLO1≥3.1. (p: 0.019). When the effect of NLO1 on OS was analyzed, the median overall survival was 19 months [95% CI (16.34-21.66)] in the NLO1<3.1 patient group, while the median OS value was 13 months [95% CI (10.80-15.20)] in the NLO1≥3.1 patient group was calculated. Low NLO1 was found to be associated with longer PFS1 and OS in SCLC patients. The number of patients with NLO2<4.1 was divided into two groups as 15 (60%) and 10 (40%) patients with NLO2≥4.1. While the median PFS2 value was 6 months [95% CI (5.19-6.80)] in the NLO2<4.1 patient group, the median PFS2 value was 3 months [95% CI (1.45-4.55)] in the NLO2≥4.1 group. It was observed that patients with low NLO2 values had longer progression-free survival (PFS2) after 2nd line chemotherapy compared to patients with high NLO2 values. This difference in survival was statistically significant in the Long Rank (Mantel-Cox) analysis (p:0.02). The number of patients who received curative radiotherapy to the lung was 15 (24%), and the number of patients who did not receive it was 47 (76%). The median PFS1 was 11 months in patients who received curative RT. The median PFS1 in patients who did not receive curative RT was calculated as 6 months, and this difference in progression-free survival was statistically significant [p:0.001, 95% CI (5.79-8.20)]. Conclusion: Considering the prognocytic factors affecting survival in SCLC patients, in our study; it was statistically significant that low NLO1 and curative RT to the lung were associated with longer PFS1 and OS, while low NLO2 was associated with longer PFS2. NLO1, NLO2, and curative RT were observed to be independent prognostic factors on survival. Keywords: Small cell lung cancer, neutrophil lymphocyte ratio, Progression-free survival, Overall survival, Prognostic factors, curative radiotherapy, Ki-67