Difficulty of predicting lymph node metastasis on CT in patients with rectal neuroendocrine tumors.

BACKGROUND:Surgical indications for rectal neuroendocrine tumors with potential lymph node metastasis remain controversial. Although accurate preoperative diagnosis of nodal status may be helpful for treatment strategy, scant data about clinical values of lymph node size have been reported. The aim of this retrospective study was to investigate the relationship between lymph node size and lymph node metastasis. METHODS:Participants comprised 102 patients who underwent rectal resection with total mesenteric excision or tumor-specific mesenteric excision and in some cases additional lateral pelvic lymph node dissection for rectal neuroendocrine tumor between June 2005 and September 2016. All lymph nodes from specimens were checked and measured. RESULTS:Pathological lymph node metastasis was confirmed in 37 patients (36%), including 6 patients (5.8%) with lateral pelvic lymph node metastasis. A total of 1169 lymph nodes in the mesorectum were retrieved from all specimens, with 78 lymph nodes (6.7%) showing metastasis. Mean length (long-axis diameter) of metastatic lymph nodes in the mesorectum was 4.31 mm, significantly larger than that of non-metastatic lymph nodes (2.39 mm, P<0.01). The optimal cut-off of major axis length for predicting mesorectal lymph node metastasis was 3 mm. We could predict lymph node metastasis in only 7 patients (21%) from preoperative multidetector-row computed tomography. CONCLUSIONS:Metastatic lymph nodes were small, so predicting lymph node metastasis from preoperative computed tomography is difficult. Alternative modalities with a scan width less than 3 mm may be needed to predict lymph node metastasis of rectal NET with low cost and labour requirements

Evaluation of the delta-shaped anastomosis in laparoscopic distal gastrectomy: midterm results of a comparison with Roux-en-Y anastomosis

Various methods of reconstruction after laparoscopic distal gastrectomy (LDG) have been developed and published, whereas only a limited number of reports are available on the utility of the delta-shaped anastomosis (Delta). This study compared Delta and Roux-en-Y anastomoses (RY), with the aim to clarify the utility of Delta. Stage 1 gastric cancer patients who had undergone LDG with Delta (group D, n = 68) and those who had undergone LDG with RY (group RY, n = 60) were compared in terms of operative outcomes, postoperative clinical symptoms, gastrointestinal fiberscopic findings, and changes in body weight. Both the operative and anastomotic times were significantly shorter in group D (230 and 13 min, respectively) than in group RY (258 and 38 min, respectively) (p < 0.001). Among the complications observed at the anastomotic site, obstruction was seen in one group D patient and two group RY patients but was relieved with conservative management. Postoperative clinical symptoms were reported for 26.4 % of the group D patients but had decreased to 5.9 % 1 year later. Group RY yielded similar results. Upper gastrointestinal fiberscopy performed 1 year postoperatively showed no intergroup differences in the incidence of gastritis or residual retention and a significantly more frequent occurrence of bile reflux in group D. Postoperative weight changes did not differ between the two groups. Delta reconstruction after LDG is a safe and effective procedure that is totally laparoscopic, less time consuming, and associated with a favorable postoperative course and a better quality of life

Spontaneous regression of advanced transverse colon cancer with deficient mismatch repair: a case report

Abstract Background Spontaneous regression (SR) of cancer occurs in 1 in 60,000–100,000 patients. This phenomenon has been reported in almost all cancer types, most commonly neuroblastoma, renal cell carcinoma, malignant melanoma, and lymphoma/leukemia. However, SR in colorectal cancer (CRC) is extremely rare, particularly in advanced cases. Hence, this report describes a very rare case of spontaneous regression of advanced transverse colon cancer. Case presentation A 76-year-old female with anemia was diagnosed with a type II well-differentiated adenocarcinoma in the middle transverse colon. Two months later, a second colonoscopy examination was performed for preoperative marking, and it revealed tumor shrinkage and a shift to type 0–IIc morphology. Endoscopic tattooing was then performed, followed by a laparoscopic partial resection of the transverse colon with D3 lymph node dissection. However, the resected specimen contained no tumor, and colonoscopy showed no tumor remnants in the remaining colon. Histopathological examination revealed mucosal regeneration and a mucus nodule in between the submucosal and muscular layers, with no cancer cells detected. Immunohistochemical analysis revealed the loss of MutL homolog 1 (MLH1) and postmeiotic segregation increased 2 (PMS2) expression in the cancer cells of biopsied specimens, suggesting deficient mismatch repair (dMMR). The patient continues to be followed up until 6 years postoperatively, and no recurrence has been observed. In this study, we also reviewed similar reported cases of spontaneous regression of cancer involving dMMR. Conclusion This study presents a rare case of spontaneous regression of advanced transverse colon cancer wherein dMMR is strongly involved. However, further accumulation of similar cases is needed to elucidate this phenomenon and to develop new treatment strategies for CRC