Combination therapy for patients with advanced forms of distal rectal cancer during neoadjuvant thermoradiotherapy

Objective: to evaluate the efficacy of combination therapy in patients with stage сT3N0M0 and сT2–3N1–2M0 distal rectal cancer during a short course of neoadjuvant thermoradiotherapy compared to radiotherapy or surgical treatment alone.

Materials and methods. A total of 166 patients received 3 sessions of local microwave hyperthermia (LMH) at a temperature of 43–45 °C for 60 minutes during a short course of radiotherapy (LMH + CT); 138 patients received combination treatment (CT) using preoperative radiotherapy alone; 197 patients received surgical treatment (ST) only.

Results. In patients receiving LMH + CT, overall incidence of complications was 38.6 % and did not significantly differ from that in patients receiving ST (p = 0.8464) and CT (p = 0.5383). We observed no significant differences in the severity of postoperative complications (according to the Clavien–Dindo classification) between the three groups of study participants treated using different regimens. The incidence of relapses was 6 % in the LMH + CT group vs 17.3 % in the ST group (p <0.0011) and 10.9 % in the CT group (p = 0.1258). Relapse-free survival rates were significantly higher in patients receiving LMH + CT than in patients who had ST alone: 59.4 % vs 51 % (p = 0.04). Difference in relapse-free survival between the CT and ST groups was not significant (56.5 % vs 51 %, respectively, p = 0.07). The frequency of therapeutic pathomorphosis was significantly higher (p <0.00001) in the LMH + CT group than in the CT group (14.9 % and 1.5 %, respectively).

Conclusions. LMH has a universal radiosensitizing potential that can increase tumor radiosensitivity and improve treatment outcomes.

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