Surgical stage in sequential therapy of unresectable oral cancer T3-4bN0-3M0: evaluation of treatment results

Introduction. Unresectable oral cancer is an urgent and complex problem in modern oncology. Annually, the proportion of patients with stage III–IV is 35 %, and the one-year mortality rate for this pathology reaches 32 %. Patients with advanced oral tumors usually have a negative prognosis and treatment tactics are limited to radiation therapy (RT), chemoradiation therapy, or sequential therapy, including induction chemotherapy (CT). Polymodal therapy for oral cancer is of particular interest in the treatment of pathology in this area.The study objective – to analyze the results of sequential treatment, including induction CT followed by RT and induction CT followed by surgery and RT in patients with unresectable oral cancer (T3–4bN0–3M0).Materials and methods. This retrospective study included 30 patients (11 women and 19 men) with primary non-resectable squamous cell carcinoma of the oral cavity (T3–4bN0–3M0) who received 2–3 courses of induction chemotherapy (CT) with DCF (docetaxel, cisplatin, 5-fluorouracil). Mean patients’ age was 61.2 years. The first treatment stage included induction CT according to the following scheme: docetaxel (75 mg/m2 /day on day 1) + cisplatin (75 mg/m2 /day on day 1) + 5-fluorouracil (1000 mg/m2 /day on days 1–4) repeated every 21 days. Study participants were divided into 2 groups according to their objective response to CT. Patients with resectable residual tumors have undergone surgery (after induction CT) followed by radical radiation therapy (RT) (induction CT + surgery + RT). Patients with non-resectable residual tumors/no objective response/no complete response after induction CT have undergone radical RT (induction CT + RT).Results. The objective response rate (ORR) to induction CT was 66.6 % (20 / 30). Five out of thirty patients (16.7 %) received no subsequent therapy: 3 individuals developed grade III–IV adverse events, while 2 individuals had progressive disease. One-third of patients (10 / 30; 33.3 %) had surgery followed by RT. Half of patients (15 / 30; 50 %) received RT after induction CT. The two-year relapse-free survival rates in the groups of induction CT + surgery + RT and induction CT + RT was 14 and 16 %, respectively (p = 0.49). The two-year overall survival rates in the same groups were 44 and 38 %, respectively (р = 0.74).Conclusion. Resectability was achieved in 33.3 % (10 / 30) of patients with initially unresectable oral cancer after induction CT. A sequential therapy regimen, including a surgical stage after induction CT, did not demonstrate a statistically significant increase in overall and disease-free survival rates. Sequential multimodal treatment of common oral cancers has some potential, but requires further study to assess its significance.