Neoadjuvant chemotherapy without radiation therapy for rectal cancer with negative prognosis

Abstract

   Aim: to assess the effectiveness of neo-CT in the FOLFOX6 regimen in patients with mid- and upper rectal cancer (RC)associated with poor prognosis.   Patients and methods: fifty-two patients were included into study. All had neo-CT with subsequent surgical treat-ment between 2017 and 2021. Of them 94.2% had stage III and 5.8% had stage II. An extramural vascular invasionwas detected by MRI in 33 (63.5%) patients. The distance between the tumor and the mesorectal fascia was ≤ 2 mmin 17%. All patients had 4 cycles of neo-CT in FOLFOX6 regimen followed by surgery.   Results: the compliance (≥ 4 cycles of neo-CT) was 82.7 % (n = 43). The overall toxicity rate was 35.6 %. Sphincter-saving surgery was performed in 51 (98.1 %) patients. Postoperative morbidity was 25.0 %. Final pathology revealed stage III in 29 (55.8 %) patients, stage 0 — stage II — in 22 (42.3 %). In accordance with the degree of pathomorphosis (CAP, 2019), 12 (23.1 %) patients showed a partial response. In one patient (1.9 %) no signs of residual tumor were detected. Downstaging of the T stage compared with MRI data before neo-CT was noted in 23 (44.2 %) patients, N stage — in 29 (55.8 %). With a mean follow-up of 31 (3-54) months, local recurrences were detected in 5 (9.6 %) patients, and distant metastases in 4 (7.7 %). The cumulative 3-year recurrence rate was 11.3 ± 4.8 %. The three-year overall and recurrence-free survival rate was 88.2 ± 5.8 % and 76.4 ± 7.4 %, respectively.   Conclusion: the multimodal approach for RC with adverse prognostic factors using neo-CT in the FOLFOX6 regimenis well tolerated by patients, has a small toxicity and postoperative morbidity as well. It is necessary to develop newpathology criteria for tumor response to neo-CT.