Brief insight regarding the use of transanal, laparoscopic, and robotic total mesorectal excision for rectal cancer

Abstract

In this article, we provide an important commentary on the original study Lu et al, which offers insight into the surgical efficacy of transanal total mesorectal excision (TaTME) vs laparoscopic total mesorectal excision (LapTME) in the management of low-lying locally advanced rectal cancer (LARC). We focus specifically on the rate of postoperative complications between the two using existing data from the literature. We additionally introduce robotic total mesorectal excision (RTME) and look at its postoperative complications relative to the TaTME and LapTME. LARC has been conventionally approached by open surgery. However, minimally invasive techniques have emerged over the past two decades as alternatives to open total mesorectal excision, namely robotic, laparoscopic, and transanal. Each approach has its supporters, but conflicting data on resection outcomes and complications has fueled ongoing debate over the optimal minimally invasive technique for low/mid-LARC. This article aims to extend on the data regarding the use of TaTME and RTME in the treatment of low/mid-LARC and further elaborate on their comparative efficacy relative to LapTME.

Key Words: Colorectal cancer; Total mesorectal excision; Laparoscopic excision; Surgical techniques; Surgical outcomes

Core Tip: Total mesorectal excision (TME) is the standard of treatment for patients with low/mid locally advanced rectal cancer. This article compares the three minimally invasive surgical approaches (robotic, transanal, and laparoscopic TME) and their comparative efficacy relative to each other using the existing data in the literature.

INTRODUCTION

Colorectal cancer (CRC) is a frequently diagnosed malignancy and the third most deadly cancer worldwide[1]. CRC incidence has been steadily increasing globally, particularly in developing countries that have adopted the Western way of life[1,2]. Obesity, high red meat consumption, sedentary lifestyle, tobacco use, and alcohol are significant risk factors for the malignancy[1-3]. Despite simultaneously evolving medical treatment with its rising incidence, surgical resection remains the standard approach for patients with rectal carcinoma[3,4]. Total mesorectal excision (TME) is the first-line surgical technique[5]. Open TME was conventionally performed in the mid-1980s; however, minimally invasive techniques have emerged as alternatives over the past two decades[5-7]. These include robotic, laparoscopic, and transanal TME for rectal cancer. There are supporters for each of these techniques in the medical community. However, conflicting evidence regarding specimen quality and complication rate has generated discussions regarding the optimal approach for low/mid locally advanced rectal cancer (LARC). This article aims to provide data from the existing literature, which suggests that both transanal TME (TaTME) and robotic TME (RTME) are preferred surgical approaches compared to laparoscopic (LapTME) for patients with low/mid-LARC.

EXISITING LITERATURE ON TME FOR TREATMENT OF LOW/MID-LARC

The retrospective study by Lu et al[8] which compared the efficacy of LapTME to TaTME, included a total of 94 patients with low-lying LARC who underwent minimally invasive surgery at a local hospital in China between 2022 and 2024[8]. The patients were selected and divided into TaTME (n = 50) and LapTME (n = 44) groups. Primary outcomes were anal function recovery, levels of surgical stress response, surgery-related indicators, surgical specimens, complication rate, visual analogue score after surgery, and quality of life. Results from the study showed that TaTME, when compared to LapTME, improved anal function, accelerated postoperative recovery, and reduced postoperative stress, showing it to be safer for patients with LARC. Although complication rates between the two (Table 1) were similar, the quality of resection specimens (Table 2) was higher among the TaTME group, contributing to a quicker postoperative recovery.

Table 1 Comparison of complications modified, n (%).

Groups	LapTME (n = 44)	TaTME (n = 50)	P value
Anastomotic fistula	1 (2.27)	1 (2.00)
Anastomotic bleeding	3 (6.82)	2 (4.00)
Ileus	3 (6.82)	2 (4.00)
Incision infection	1 (2.27)	0 (0.00)
Total occurrence	8 (18.18)	5 (10.00)	0.252

Comparison of complications modified from Lu et al[8]. LapTME: Laparoscopic total mesorectal excision; TaTME: Transanal total mesorectal excision.

Table 2 Comparison of resection specimens modified.

Groups	LapTME (n = 44)	TaTME (n = 50)	T value	P value
Distal incisal margin (cm)	2.90 ± 0.78	3.40 ± 0.57	3.577	< 0.001
Specimen length (mm)	10.45 ± 2.37	12.12 ± 2.27	3.486	< 0.001
Total number of lymph nodes cleared (n)	11.18 ± 3.22	11.72 ± 3.26	0.806	0.422

Comparison of resection specimens modified from Lu et al[8]. LapTME: Laparoscopic total mesorectal excision; TaTME: Transanal total mesorectal.

Another retrospective study by de'Angelis et al[9] compared the efficacy of all three minimally invasive surgical approaches using the European magnetic resonance imaging (MRI) and Rectal Cancer Surgery III database in patients who underwent TME between 2013 and 2022. A total of 468 patients were included, where 190 (40.6%) received LapTME, 141 (30.1%) received RTME, and 137 (29.3%) patients received TaTME. The primary outcome was the complication rate. Secondary outcomes included overall survival, disease-free survival, intraoperative variables (i.e., blood loss, operating time, conversion rate), postoperative variables (i.e., length of hospital stay), and quality of surgical resection. Comparative analysis after matching propensity score showed an elevated rate of postoperative complications for LapTME compared to both TaTME [odds ratio (OR) 2.87, 95%CI: 1.72-4.80] and RTME (OR 1.80, 95%CI: 1.11-2.91). TaTME (0.7%) and RTME (1.4%) were both correlated with smaller conversion rates to open surgery when juxtapose to LapTME (8.8%, P < 0.001). RTME was associated with a smaller rate of anastomotic leakage (grade A) (2%) compared to both LapTME (8.8%) and TaTME (8.1%, P = 0.031). Duration of hospital stay and time to flatus were briefer for patients treated with TaTME (P = 0.001 and 0.003, respectively).

No differences were observed in blood loss, operative time, mortality, intraoperative complications, R0 resection, survival, and readmission. This multicenter cohort study demonstrated that TaTME and RTME improved surgical outcomes in patients with low/mid-LARC compared to LapTME.

DISCUSSION

With the vagueness of the existing literature, this article adds to the existing data, suggesting that the newer minimally invasive techniques (RTME and TaTME) are better treatment options than LapTME for patients with low/mid-LARC. A relatively large cohort study by de'Angelis et al[9] showed that LapTME correlated with higher conversion rates to open surgery, reduced rate of stoma closure, and a higher incidence of postoperative complications compared to both TaTME and RTME. A meta-analysis by Lo Bianco et al[10] demonstrated that TaTME resulted in shorter hospitalizations, high-quality LARC operation, a lower percentage of tumor-positive margins, and a lower incidence of anastomotic complication such as leakage compared to LapTME.

Despite the evidence, LapTME remains the most common minimally invasive approach for LARC[9,11]. A nationwide study in Denmark showed that 48% of all TMEs were done laparoscopically, compared to 29.8% robotically and 13% transanally[12]. This widespread adoption is most likely due to early introduction that stuck within the surgery community, mainly related to surgeon’s preferences and experience[9,13]. The increased use of LapTME is also seen globally compared to TaTME and RTME. It is important to note that the laparoscopic technique is highly challenging and requires skilled surgeons. TaTME and RTME have emerged as valuable alternative options to bypass technical limitations of LapTME and produce better surgical outcomes[8,12-14].

RECENT ADVANCES IN RESEARCH

Several trials, such as the COREAN studies and the MRC-CLASSICA, demonstrated no significant difference between LapTME and open surgery with respect to disease-free survival rates and local recurrence, ultimately favoring the efficacy and safety of laparoscopy in managing LARC in certain patients[15,16]. However, contemporary studies, namely ALaCaRT and ACOSOG Z6051, have failed to show the non-inferiority of laparoscopy compared to open surgery with respect to morbid outcomes, raising questions regarding oncologic safety of LapTME in the treatment of LARC[17,18].

RTME and TaTME were launched as alternative approaches to reduce the technical challenges of LapTME while maintaining high-quality oncologic outcomes. Recent meta-analyses based on several retrospective studies and one randomized controlled trial demonstrated similar results concerning oncologic and postoperative outcomes of TaTME compared with LapTME[19-21].

CONCLUSION

The newer minimally invasive techniques, including RTME and TaTME, have been shown to improve surgical outcomes compared to LapTME in treating low/mid-LARC. However, laparoscopy still dominates in the surgical community due to physician preference and experience. The existing literature suggests that RTME and TaTME are, in fact, both better and suitable alternatives to LapTME as they possess better postoperative outcomes.