CLINICAL OUTCOMES OF RECTAL NEUROENDOCRINE TUMORS TREATED BY ESMR-L

Aims:

The therapeutic strategies for the rectal neuroendocrine tumor (NET) have not been still established. We often use endoscopic submucosal resection with ligation device (ESMR-L) for treatment of rectal NET. We conducted this study to evaluate the clinical outcomes of rectal NET treated by ESMR-L.

Methods:

Between May 2002 and December 2017, 191 patients with 192 rectal NET (G1) underwent ESMR-L in our hospital. Firstly, we investigated association between clinicopathological characteristics including endoscopic findings and therapeutic outcomes. Curative resection was defined as R0 resection without LVI. Subsequently, the long-term outcomes after a 45-months follow-up period were also evaluated.

Results:

The average age was 52 years, and the majority were male (74%). Most of the lesions were located at Rb (82%), and the average size was 4.6 mm. Of the 192 lesions, 191 and 122 achieved complete and curative resection, respectively. Multivariate logistic regression analyses revealed that the tumor size ≧5 mm (OR: 2.96, 95% CI; 1.60 – 5.45, P= 0.001) and presence of central depression (OR: 5.50, 95% CI; 1.68 – 18.0, P= 0.005) are significantly associated with non-curative resection. 13 of the 70 lesions with non-curative resection underwent additional surgery, among which 2 cases had histological lymph node metastasis. No case had local or distant metastases during the follow-up period. With respect to complications, one perforation (0.5%) and 13 delayed bleeding (6.8%) were observed, but they were successfully managed conservatively.

Conclusions:

ESMR-L is a feasible measure as an endoscopic resection for rectal NET. Given that there was no recurrence without additional surgery in cases regarded as non-curative resection, observation without additional surgery might be allowed. Further investigations are needed to establish the indication of endoscopic treatment.