Comparative analysis of minimally invasive treatment of early rectal cancer

Introduction. Currently, the main treatment method of early rectal cancer is surgery, and in the modern clinical practice minimally invasive methods that reduce perioperative risks are preferable.
Aim. To analyze the results of treatment of early rectal cancer using various minimally invasive surgical techniques.
Materials and methods. Retrospective analysis of patients with early forms of malignant rectal neoplasms subjected to minimally invasive surgery at the N . N . Alexandrov Republican Scientific and Practical Center of Oncology and Medical radiology between January 2013 and December 2023 was performed. All patients included in the final analysis were divided into two groups: the first group of patients underwent surgical treatment in the form of transanal tumor resection (TTR), the second in the form of transanal endoscopic microsurgery (TEM). Indications for minimally invasive surgery were: cancer invading only the submucosal or mucosal layers; small tumors less than 3 cm in size, not exceeding 30 % of the rectal circumference, without lymphovascular, perineural invasion, without clinical involvement of the lymph nodes, accessible for transanal full-thickness excision. The main endpoints were operative time, blood loss volume, postoperative in-hospital time, and postoperative complications (according to the Clavien–Dindo classification). Overall and recurrence-free survival were also evaluated for both groups.
Results. Patients (n = 66) with early forms of malignant tumors who received primary surgical treatment and were included in the final analysis were divided into groups depending on the surgical treatment received: transanal surgery (n = 49) and transanal endoscopic microsurgery (n = 17). Median follow-up was 47 months. Postoperative complications were observed in 4 patients: 2 (4.1 %) in the TTR group and 2 (11.8 %) in the TEM group (p = 0.235). The differences in overall and recurrence-free survival between the groups were not statistically significant (odds ratio 1.11; 95 % confidence interval 0.50–2.45; p = 0.795). Postoperative pathomorphological examination led to T category restaging in 31.4 % of cases, in 21.4 % of cases towards higher T stage. Additionally, 12 patients had pT2 stage (10 in the TTR group, 2 in the TEM group).
Conclusion. Transanal tumor resection and transanal endoscopic microsurgery have comparable complication and survival rates. In order to increase the accuracy of preoperative staging and to determine indications for minimally invasive surgery, it is necessary to carefully carry out preoperative procedures and provide an accurate diagnostic algorithm.

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