This month's selected paper evaluates the long-term oncological outcomes of transanal total mesorectal excision (TME) compared with laparoscopic TME in patients with mid-low rectal cancer.
Transanal vs Laparoscopic Total Mesorectal Excision and 3-Year Disease-Free Survival in Rectal Cancer: The TaLaR Randomized Clinical Trial
Zeng Z, Luo S, Zhang H, Wu M, Ma D, Wang Q, Xie M, Xu Q, Ouyang J, Xiao Y, Song Y, Feng B, Xu Q, Wang Y, Zhang Y, Shi L, Ling L, Zhang X, Huang L, Yang Z, Peng J, Wu X, Ren D, Huang M, Lan P, Wang J, Tong W, Ren M, Liu H, Kang L; for the Chinese Transanal Endoscopic Surgery Collaborative (CTESC) Group.
JAMA. Published online 23 January 2025. doi:10.1001/jama.2024.24276.
What is known about the subject?
Total mesorectal excision (TME) is the gold standard for surgical management of mid-low rectal cancer, significantly reducing local recurrence rates and improving oncological outcomes [1]. Laparoscopic TME has been widely adopted due to its minimally invasive nature, resulting in shorter recovery times and lower postoperative morbidity [2]. However, achieving optimal mesorectal excision can be challenging in narrow pelvic spaces, particularly in male and obese patients, leading to higher conversion rates to open surgery and increased complications [3]. Transanal TME has emerged as an alternative approach that offers enhanced visualisation and facilitates dissection in challenging pelvic anatomy [4]. Although previous studies have demonstrated superior short-term outcomes with transanal TME, including lower conversion rates and improved specimen quality, there has been ongoing debate regarding its long-term oncological safety compared with laparoscopic TME [5].
What does this study add?
This phase III, multicentre, randomised, open-label, noninferiority clinical trial compared the 3-year disease-free survival (DFS) of transanal TME with laparoscopic TME in patients with mid-low rectal cancer. A total of 1,115 patients across 16 centres in China were randomised 1:1 to undergo either transanal (n=558) or laparoscopic (n=557) TME.
- Primary outcome: Three-year DFS was 82.1% in the transanal TME group vs. 79.4% in the laparoscopic TME group (difference: 2.7%, 97.5% CI: -3.0% to 8.1%), meeting the noninferiority threshold.
- Secondary outcomes: Three-year local recurrence rates were 3.6% for transanal TME vs. 4.4% for laparoscopic TME. Three-year overall survival rates were 92.6% vs. 90.7%, respectively.
- Subgroup analyses: While overall oncological outcomes were comparable, in patients with stage III disease, transanal TME demonstrated a trend toward improved overall survival (HR: 0.51, 95% CI: 0.29-0.89), suggesting a potential benefit in more advanced disease stages.
- Surgical quality: The study ensured rigorous surgical quality control by requiring participating surgeons to have significant prior experience in both laparoscopic and transanal TME procedures.
Implications for colorectal practice
The TaLaR trial provides strong evidence that transanal TME is noninferior to laparoscopic TME in terms of 3-year DFS. Additionally, it demonstrates comparable local recurrence rates and overall survival, reinforcing its viability as an alternative, particularly in challenging pelvic anatomy. However, the learning curve associated with transanal TME remains a concern, as early complications and suboptimal resections have been reported in less-experienced centers [6]. These findings align with previous studies that reported promising short-term outcomes but called for longer follow-up to confirm oncological safety [5, 7]. Further research is warranted to explore functional outcomes, patient-reported quality of life, and its applicability in the context of total neoadjuvant therapy.
References
- Heald RJ, Husband EM, Ryall RD. The mesorectum in rectal cancer surgery—the clue to pelvic recurrence? Br J Surg. 1982;69(10):613-616.
- Bonjer HJ, Deijen CL, Abis GA, et al. A randomized trial of laparoscopic versus open surgery for rectal cancer. N Engl J Med. 2015;372(14):1324-1332.
- Quirke P, Steele R, Monson J, et al. Effect of the plane of surgery achieved on local recurrence in patients with operable rectal cancer: a prospective study using data from the MERCURY trial. Lancet. 2010;375(9719):821-827.
- Lacy AM, Tasende MM, Delgado S, et al. Transanal total mesorectal excision for rectal cancer: outcomes after 140 patients. J Am Coll Surg. 2015;221(2):415-423.
- Roodbeen SX, Penna M, Mackenzie H, et al. Local recurrence and disease-free survival after transanal total mesorectal excision: retrospective analysis of 767 patients. Ann Surg. 2019;270(5):835-842.
- Larsen SG, Wiig JN, Christensen HO, et al. Extended experience with transanal total mesorectal excision for rectal cancer. Surg Endosc. 2019;33(1):15-24.
- de Lacy FB, Rattner DW, Adelsdorfer C, et al. Transanal natural orifice specimen extraction for rectal cancer: transanal total mesorectal excision. Dis Colon Rectum. 2018;61(12):1320-1327.
