Introduction: Lung cancer is the most common cause of cancer‑related death. Accurate and easy‑to‑use prognostic factors are necessary. Increased platelet count might be a potential prognostic factor.

Objectives: We aimed to investigate the relationship between thrombocytosis and stage of lung cancer and to assess the frequency and clinical importance of thrombocytosis in this patient group.

Patients and methods: We retrospectively analyzed hospital records of consecutive patients with non–small cell lung cancer (NSCLC) who underwent curative‑intent pulmonary resections.

Results: Of 323 patients, 285 patients with NSCLC were selected (mean [SD] age, 66.55 [8.52] years; men, 63.86%). Squamous cell carcinoma was diagnosed in 130 patients (45.61%); adenocarcinoma, in 128 (44.91%); large cell carcinoma, in 16 (5.61%); and adenosquamous carcinoma, in 11 (3.86%). The prevalence of preoperative thrombocytosis in the whole sample was 10.18% (n = 29). Anemia was more common in patients with thrombocytosis compared with those without thrombocytosis (65.52% vs 30.08%; P <0.001). Thrombocytosis was found in 22.41% of patients with stage III+IV cancer and in 3.82% of those with stage I (P <0.001). Moreover, in patients with no metastases (N0, M0 according to the 7th edition of the TNM classification), thrombocytosis was more frequent in the group with stage II than in that with stage I cancer (3.85% vs 20.00%; P = 0.002). Thrombocytosis was also more frequent in patients with N2 than with N1 disease (9.76% vs 23.81%; P = 0.09).

Conclusions: Thrombocytosis is often observed in patients with NSCLC and is significantly associated with the higher stage of disease.