[Combined treatment of rectal cancer with moderate risk of tumor progression]

To increase the effectiveness of combined treatment in patients with rectal cancer and moderate risk of progression based on the concept of polyradiomodification (PRM).

The study included 337 patients with rectal cancer and moderate risk of tumor progression. A short course of radiotherapy (cRT) (5x5 Gy) combined with several radiomodifiers (cRT+PRM) was performed in 147 (43.6%) patients. Other 190 (56.4%) patients underwent cRT. The following radio modifiers were used: three-time application of local microwave hyperthermia (Yacht-3 or Yacht-4 devices), two-time intrarectal delivery of a biopolymer composition with Metronidazole before the 3rd and 5th irradiation sessions and two-week oral administration of Capecitabine (Xeloda) at a daily dose of 2.0 g/m². Surgery was performed in 4-6 weeks after radiotherapy.

CRT+PRM program increased 5-year relapse-free survival up to 81.3% compared to 60.3% after cRT alone (p=0.0003) due to significant reduction of the incidence of cancer recurrence from 8.4% to 0.7% (p=0.0013). More effective local growth control expanded the indications for sphincter-sparing surgery. These procedures were performed in 89.1% and 70.5% of patients, respectively (p=0.00001). In the cRT+PRM group, sphincter-sparing surgery reduced incidence of cancer recurrence from 13.7% to 0.8% (p=0.0110), distant metastases - from 23.9% to 13.7% (p=0.00349).

Radiomodification in neoadjuvant radiotherapy is justified in patients with moderate risk of tumor progression, improves long-term results and increases the incidence of sphincter-sparing surgery.