Lung cancer in Bulgaria ‒ diagnosis, treatment, and factors affecting survival

In Bulgaria, lung cancer incidence and mortality rates are rising in both men and women. The study aims to present a picture of lung cancer diagnosis and treatment process and to identify factors affecting survival in advanced lung cancer patients (LCP) treated with systemic therapy.

Data from LCP admitted at the Medical Oncology Department were retrospectively collected from electronic and hard-paper database for a 10-year period (January 2005–2015). The test for frequencies was used to describe parameters. Kaplan–Mayer estimates with two-sided 95 % confidence interval (CI) were calculated for clinical and laboratory prognostic factors in advanced LCP who received medical therapy. Cox-regression model was used for the evaluation of significant prognostic factors’ impact on survival. Statistical analyses were performed using SPSS 9.0 software.

Data from 204 LCP were retrospectively analyzed for a period between January 2005 and January 2015. LCP characteristics were as follows: median age 60.2 years (range 28–78), male/female (M/F) 159/55, Eastern Cooperative Oncology Group (ECOG) performance status (PS) 0–1/> 2 136/63, no comorbidity/with comorbidity 36/168, smoking history never/ever 37/149; 86.3 % LCP had stage IIIB and IV disease. In 43.2 % of LCP with negative or not performed fibrobronchoscopy (FBS), pathological diagnosis was obtained by other methods including surgical. Before treatment, patients obtained morphological verification of lung cancer—98.5 % histologically versus 1.5 % cytologically. The prevalent histo-type found was adenocarcionoma. In all, 88.7 % of LCP received systemic medical treatment while 11.3 %—palliative care. Only 2.5 % received adjuvant and 2.0 % neoadjuvant chemotherapy, while 84.2 % received medical therapy for advanced disease. In the last group, prognostic value for survival according to Cox-regression model reached ECOG performance status (PS) (HR 0.4; CI 0.23–0.63; p < 0.0001); weight loss (WL) prior to diagnosis (HR 2.03; CI 1.22–3.37; p < 0.01); number of treatment lines (HR 1.65; CI 1.2–2.67; p < 0.05); and platelet to lymphocyte ratio (PLR) (HR 0.48;CI 0.24–0.95; p < 0.001).

Lung cancer diagnosis and treatment in Bulgaria are managed according to the European guidelines. ECOG PS and WL are known prognostic factors in advanced LCP. Our results support prognostic impact of PLR on survival. However, the confirmation of this finding needs further prospective validation. The fact that the number of treatment lines impacts survival point out the importance of “continuum of care” concept in advanced LCP, treated with medical therapy.