Inside job.

Top Line: Does transanal excision after chemoradiation reduce morbidity in patients with T2 and favorable T3 rectal cancer?

The Study: T3 rectal cancer is heterogeneous with the ESMO clinical practice guidelines dividing T3 disease into 4 subcategories based on the extent of invasion beyond the muscularis propria. Some feel that ESMO T3a/b disease (<1mm and 1-5mm invasion beyond the muscularis, respectively) behaves more similar to T2 disease than more advanced T3 disease. In fact, some surgeons feel that a high quality TME alone is sufficient for low risk T3 disease. The Spanish TAU-TEM trial takes the opposite approach. TAU-TEM was a randomized, phase 3 trial designed to test whether neoadjuvant chemoradiation and transanal endoscopic microsurgery (TEM) resulted in non-inferior local recurrence and less morbidity than the standard TME. This publication describes the morbidity and initial pathologic outcomes with the final outcomes still maturing. Eligible patients (173) had T2N0 (69.8%) or the aforementioned T3a/bN0 (≤5mm invasion through the muscularis, 30.2%) disease. In addition, the tumor had to be well to moderately differentiated, ≤4cm, and within 10cm of the anal verge. In the CRT-TEM arm, patients received long-course radiation with concurrent capecitabine, and transanal endoscopic excision was performed 8 weeks after CRT. A question with any neoadjuvant trial is what was the true original extent of disease? In the TME group, 4.9% were under-staged with T3c/d disease, 12.3% were over-staged with T1 disease, and 21% had occult nodal disease. Surgical complications, operation time, blood loss, and overall morbidity (20.7% v 50.6%) were all significantly lower in the CRT-TEM arm. Length of hospital stay was also significantly shorter (3.7 v 10.6 days). Just 4.9% of patients required a temporary ostomy compared to 76.8% in the TME group. In the CRT-TEM arm, the pCR rate was 44.3%

TBL: Compared to TME, neoadjuvant CRT and transanal excision resulted in less than half the rate of post-operative morbidity with a 44% pCR rate for patients with T2 and early T3 rectal cancer. | Serra-Aracil, Ann Oncol 2022