The influence of tumor staging on life expectancy with the use of chemoradiotherapy in small cell lung cancer treatment

Background. The treatment of small cell lung cancer is the subject of intensive research in the field of chemotherapy of malignant tumors. The use of radiation treatment and chemotherapy leads to 80–100% of the objective effect, and 50–70% of patients achieve complete remission, which is the main goal of combined therapy, although this treatment cannot help to prevent the growth of the tumor.

Aim. The aim of the study was to examine the relationship between the stage of primary tumor and the life expectancy of patients with small cell lung cancer on receiving complex chemoradiotherapy.

Methods. The study included 483 patients with small cell lung cancer who received chemoradiotherapy treatment between 1995 and 2015. Out of 483 patients, 439 (90.9%) were men and 44 (9.1%) were women. Total number of patients in the age group of 65–69 were 212 (43.8%). According to the tumor staging, they were distributed as follows: IA [T₁N₀M₀] – 23 (4.1%) patients; IB [T₂N₀M₀] – 86 (15.3%) patients; IIA [T₁N₁M₀] – 33 (5.9%) patients; IIB [T₂N₁M₀ – 88 (15.7%), T₃N₀M₀ – 78 (14.0%)] – 166 (29.7%) patients; IIIA [T₃N₁M₀ – 58 (10.4%), T₁N₂M₀ – 37 (6.6%), T₂N₂M₀ – 34 (6.1%), T₃N₂M₀ – 46 (8.2%)] – 175 (31.3%) patients. The total of 31.3% of patients had stage IIIA. Metastases to regional lymph nodes N1 were detected in 155 (32.1%) patients, N2 in 101 (21%) patients, and N3 in 36 (7.5%) patients.

Results. The life expectancy of patients receiving complex conservative treatment primarily depends on the size of the primary tumor in the lung and secondarily on the presence of regional metastases. The average life expectancy for T₁N₀ is 30.2 months, which is 18 months more compared with T₂N₀ and 22.7 months more than T₃N₀, but these differences begin to decrease with the appearance of metastases in regional lymph nodes: T₁N₁ average life expectancy is 22.4 months, which is 14.9 months more than T₂N₁ and 20 months more than T₃N₁. The lowest average life expectancy is in patients with N₂, so with T₁ it was 11.4 months, which is 9 months more than with T₂ and 9.8 months more than with T₃; this means that the presence of mediastinal metastases in patients with T₂ and T₃ tumors have a negative predictive effect of the average life expectancy.

Conclusions. According to the results obtained, life expectancy in patients with T_1–3N_0–2M₀ tumor staging receiving chemoradiotherapy depends primarily on the size of the primary lung tumor and secondarily on the regional lymph node metastases. Lung cancer treatment is much more effective when the disease is in its earlier stages, that is, T₁N_0–1.