Risk factors for lymph node metastasis and prognosis in colorectal neuroendocrine tumours

Abstract

Purpose The detection rate of colorectal neuroendocrine tumours (CR-NETs) is increasing, but their treatment is still controversial. Lymph node metastasis is an important reference index for the selection of treatment. The aim of our study was to investigate the factors associated with lymph node metastasis and prognosis of CR-NETs. Methods The case characteristics of patients with colorectal neuroendocrine tumours from January 2011 to December 2020 were retrospectively analysed, including age, gender, tumour size, tumour location, lymph node metastasis, pathological grade and follow-up. Results A total of 195 cases of CR-NETs were included in this study. When 15 mm was used as the cut-off value, the sensitivity, specificity and area under the curve (AUC) of lymph node metastases were 95.9%, 95.2% and 0.986, respectively. Multivariate analysis suggested that tumour size ≥ 15 mm (OR: 30.517, 95% CI: 1.250 ~ 744.996, p = 0.036) and lymphovascular invasion (OR: 42.796, 95% CI: 2.882 ~ 635.571, p = 0.006) were independent risk factors for lymph node metastasis. Age ≥ 56 (HR: 7.434, 95% CI: 1.334 ~ 41.443, p = 0.022) and distant metastasis (HR: 24.487, 95% CI: 5.357 ~ 111.940, p < 0.001) were independent prognostic factors in multivariable analyses. Conclusions When the size of a CR-NET is ≥ 15 mm, the risk of lymph node metastasis is higher, and it is recommended to choose the surgical method carefully. Tumour size and lymphovascular invasion were independent risk factors for lymph node metastasis. Age ≥ 56 and distant metastasis were independent prognostic factors.

Comparison between endoscopic mucosal resection with a cap and endoscopic submucosal dissection for rectal neuroendocrine tumors

“…Second, the surgical procedure is not performed by the same physician, so differences between different people are inevitable. In our recent study [ 29 ], tumor size greater than 15 mm was considered to be an independent risk factor for lymph node metastasis in patients with colorectal neuroendocrine neoplasm, so 15 mm was used as the cut-off value to study the difference in endoscopic resection methods. We noticed that a recent report [ 30 ] suggested that tumor size greater than 11.5 mm was independent risk factor for lymph node metastases in patients with R-NETs.…”

Lymph Node Metastasis, Radical Surgery, and Prognosis in Well-Differentiated Neuroendocrine Tumors of the Rectum

“…Hiyoshi et al's findings are consistent with prior investigation, demonstrating an increase in LN metastasis rate as tumor size increases. 3 However, a particularly interesting finding comes from Hiyoshi et al's evaluation of LN metastasis in < 1 cm size tumors, where they observed a LN metastasis rate of 22% in tumors < 0.5 cm in size and 32% in tumors 0.5-1 cm in size; importantly, as this study included those rectal NETs that were recommended for radical surgery, these small rectal NETs also harbored other risk factors for LN metastasis, and thus, as acknowledged by the authors, the rate of LN metastasis is likely overestimated in this cohort of rectal NETs < 1 cm in size. At this time, for small < 1 cm rectal NETs, the presence of additional risk factors is not widely considered for treatment decision making; given the association of LN metastasis with poorer prognosis, and the presence of LN metastasis in these small rectal NETs with additional risk factors, further investigation is warranted in this rectal NET subset to advise of the best treatment approach, perhaps specifically in those rectal NETs with venous invasion or LVI, which has been demonstrated in this study and others, to have an impact on LN metastasis.…”