Patient population and data collection
In this multicenter, retrospective cohort study, patients aged 65 years or older, diagnosed with extensive-stage SCLC between January 2009 and December 2021 in the Medical Oncology Departments of the University of Health Sciences Dr. Abdurrahman Yurtaslan Ankara Oncology Training and Research Hospital, Ankara, Türkiye, and Gazi University School Medicine, Ankara, Türkiye, were included. Patients who were under 65 years of age at the time of diagnosis and did not develop progression after curative treatment and patients with a second malignancy were excluded from the study.
The baseline demographic characteristics of the patients (gender, age at diagnosis, and smoking status), clinicopathological data (Eastern Cooperative Oncology Group (ECOG) performance status (PS)), and tumor characteristics (stage and metastasis sites), treatment characteristics (palliative chemotherapy options, number of chemotherapy cycles, and treatment responses), laboratory findings (lactate dehydrogenase-LDH), disease progression, and survival data were examined and transferred to the database. American Joint Committee on Cancer (AJCC) Cancer Staging Manual, 8th Edition, was used for disease staging.
The two chemotherapy protocols given to the patients included in the study were as follows: (i) a combination of cisplatin and etoposide (cisplatin 80 mg/m2/day IV on day 1, etoposide 100 mg/m2/day IV on days 1-3), or (ii) a combination of carboplatin and etoposide (carboplatin area under the curve 5 (AUC5) IV on day 1, etoposide 100 mg/m2/day IV on days 1-3). Both regimens were given up to six cycles.
Response to chemotherapy was defined according to response evaluation in solid tumors criteria 1.1 (RECIST 1.1). Complete response (CR) was defined as the disappearance of all target lesions, the short axis of all pathological lymph nodes <10 mm; partial response (PR) was defined as a reduction of at least 30% in the sum of the diameters of the target lesions; progressive disease (PD) was defined as the appearance of one or more new lesions or the size of the target lesions increasing by 20% of the sum of the long diameters; and stable disease (SD) was defined as neither sufficient reduction to be considered as PR nor sufficient increase to be considered as PD.
Statistical analysis
IBM SPSS Statistics for Windows, Version 23.0 (Released 2015; IBM Corp., Armonk, New York, United States) was used for data analysis. Progression-free survival (PFS) was defined as the time from the beginning of chemotherapy treatment to disease progression or death, and overall survival (OS) was defined as the time from the date of extensive-stage diagnosis to death. Survival analyses were performed by the Kaplan-Meier method and subgroups were compared by log-rank test. Factors that may be related to PFS and OS were investigated by univariate analysis. Factors that showed significant association with survival were evaluated by multivariate Cox regression analysis. P<0.05 was considered statistically significant.
Ethical approval
Ethical approval was obtained from the Ethics Committee of the University of Health Sciences, Dr. Abdurrahman Yurtaslan Ankara Oncology Training and Research Hospital (approval number: 2022-04/1798,20.04.2022). Our study complies with the principles of the Helsinki Declaration.
In this multicenter, retrospective cohort study, patients aged 65 years or older, diagnosed with extensive-stage SCLC between January 2009 and December 2021 in the Medical Oncology Departments of the University of Health Sciences Dr. Abdurrahman Yurtaslan Ankara Oncology Training and Research Hospital, Ankara, Türkiye, and Gazi University School Medicine, Ankara, Türkiye, were included. Patients who were under 65 years of age at the time of diagnosis and did not develop progression after curative treatment and patients with a second malignancy were excluded from the study.
The baseline demographic characteristics of the patients (gender, age at diagnosis, and smoking status), clinicopathological data (Eastern Cooperative Oncology Group (ECOG) performance status (PS)), and tumor characteristics (stage and metastasis sites), treatment characteristics (palliative chemotherapy options, number of chemotherapy cycles, and treatment responses), laboratory findings (lactate dehydrogenase-LDH), disease progression, and survival data were examined and transferred to the database. American Joint Committee on Cancer (AJCC) Cancer Staging Manual, 8th Edition, was used for disease staging.
The two chemotherapy protocols given to the patients included in the study were as follows: (i) a combination of cisplatin and etoposide (cisplatin 80 mg/m2/day IV on day 1, etoposide 100 mg/m2/day IV on days 1-3), or (ii) a combination of carboplatin and etoposide (carboplatin area under the curve 5 (AUC5) IV on day 1, etoposide 100 mg/m2/day IV on days 1-3). Both regimens were given up to six cycles.
Response to chemotherapy was defined according to response evaluation in solid tumors criteria 1.1 (RECIST 1.1). Complete response (CR) was defined as the disappearance of all target lesions, the short axis of all pathological lymph nodes <10 mm; partial response (PR) was defined as a reduction of at least 30% in the sum of the diameters of the target lesions; progressive disease (PD) was defined as the appearance of one or more new lesions or the size of the target lesions increasing by 20% of the sum of the long diameters; and stable disease (SD) was defined as neither sufficient reduction to be considered as PR nor sufficient increase to be considered as PD.
Statistical analysis
IBM SPSS Statistics for Windows, Version 23.0 (Released 2015; IBM Corp., Armonk, New York, United States) was used for data analysis. Progression-free survival (PFS) was defined as the time from the beginning of chemotherapy treatment to disease progression or death, and overall survival (OS) was defined as the time from the date of extensive-stage diagnosis to death. Survival analyses were performed by the Kaplan-Meier method and subgroups were compared by log-rank test. Factors that may be related to PFS and OS were investigated by univariate analysis. Factors that showed significant association with survival were evaluated by multivariate Cox regression analysis. P<0.05 was considered statistically significant.
Ethical approval
Ethical approval was obtained from the Ethics Committee of the University of Health Sciences, Dr. Abdurrahman Yurtaslan Ankara Oncology Training and Research Hospital (approval number: 2022-04/1798,20.04.2022). Our study complies with the principles of the Helsinki Declaration.
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