Background: Radical resection with total mesorectal excision (TME) is the accepted standard of care for most rectal cancers. However, T1 rectal cancers may be at low risk for metastases and are therefore treatable with local resection. The aim of our study was to investigate whether the identification of these patients is possible through existing selection criteria.
Methods: Between 2001 and 2012, radical resection with TME was performed in 68 patients with a histologically confirmed T1 adenocarcinoma of the rectum. Each patient was staged preoperatively as lymph node negative. Patients at low risk to metastasize were defined as proposed by Hermanek and Gall (Int J Colorectal Dis 1(2):79-84, 1986), Kikuchi et al. (Dis Colon Rectum 38(12):1286-1295, 1995) and Hase et al. (Dis Colon Rectum 38(1):19-26, 1995) Postoperative morbidity, mortality, and oncological outcome were analyzed.
Results: Despite nodal negative staging, 9 of 68 patients (13 %) were node positive. Following the proposal of Hermanek and Gall, Kikuchi et al., and Hase et al., 14 % (5/37), 12 % (3/26), and 16 % (6/38) of patients, respectively, with low-risk tumors had lymph node metastases. In the univariate analysis, none of the investigated parameters could predict lymph node metastases. Following radical resection, none of the patients, regardless of nodal involvement, developed a recurrence.
Conclusions: Preoperative diagnostics regarding lymphatic tumor propagation and histomorphological assessment of tumor samples as predictors of lymph node metastasis are unreliable. Following radical resection with TME, the oncological outcome of node-positive patients with T1 rectal adenocarcinoma is comparable with that of lymph node-negative patients. Considering the lymph node metastases rate, a local excision should always be complemented with additional therapy.