PROGNOSTIC VALUE OF POST-RADIATION REGRESSION OF LOCALLY ADVANCED RECTAL CANCER

Currently, combination therapy, including preoperative irradiation of the tumor and areas of regional lymphatic drainage, has become the standard for the treatment of patients with locally advanced rectal cancer. Methods for evaluating neoadjuvant therapy response are increasingly being introduced into the practice of specialized medical centers. However, the prognostic value of tumor regression grade remains unclear. The results of numerous studies presented in modern literature are contradictory, and their comparative analysis is extremely difficult because of the abundance of post-radiation regression classifications used. This review article reflects the current views on the role and ways of assessing the therapeutic pathomorphosis of rectal cancer after radiotherapy/chemoradiotherapy.

Transplanted Fibroblasts Proliferate in Host Bronchial Tissue and Enhance Bronchial Anastomotic Healing in a Rodent Model

Introduction Healing of airway anastomoses after preoperative irradiation can be a significant clinical problem. The augmentation of bronchial anastomoses with a fibroblast-seeded human acellular dermis (hAD) was shown to be beneficial, although the underlying mechanism remained unclear. Therefore, in this study we investigated the fate of the fibroblasts transplanted to the scaffold covering the anastomosis. Material and methods 32 Fisher rats underwent surgical anastomosis of the left main bronchus. In a 2 × 2 factorial design, they were randomized to receive preoperative irradiation of 20 Gy and augmentation of the anastomosis with a fibroblast-seeded transplant. Fibroblasts from subcutaneous fat of Fischer-344 rat were transduced retrovirally with tdTomato for cell tracking. After 7 and 14 days, animals were sacrificed and cell concentration of transplanted and nontransplanted fibroblasts in the hAD as well as in the bronchial tissue was measured using RT-PCR. Results Migration of transplanted fibroblasts from dermis to bronchus were demonstrated in both groups, irradiated and nonirradiated. In the irradiated groups, there was a cell count of 7 × 104 ± 1 × 104 tomato+-fibroblasts in the bronchial tissue at day 7, rising to 1 × 105 ± 1 × 104 on day 14 (p<0.0001). Tomato+-cell concentration in hAD increased from 6 × 103 ± 1 × 103 at day 7 to 6 × 104 ± 1 × 104 at day 14 (p<0.0001). In the nonirradiated groups, tomato+-cell concentration in bronchus was 4 × 103 ± 1 × 103 on day 7 and 4 × 103 ± 1 × 103 at day 14. In the hAD tomato+ cell concentration rising from 1 × 104 ± 1 × 103 at day 7 to 2 × 104 ± 3 × 103 cells at day 14 (p = 0.0028). Conclusions Transplanted fibroblasts in the irradiated groups proliferate and migrate into the irradiated host bronchial tissue, but not in the nonirradiated groups.