Computed tomography and magnetic resonance imaging evaluation of lymph node metastasis in early colorectal cancer

AIM: To assess the role of computed tomography(CT) and magnetic resonance imaging(MRI) and establish imaging criteria of lymph node metastasis in early colorectal cancer.METHODS: One hundred and sixty patients with early colorectal cancer were evaluated for tumor location, clinical history of polypectomy, depth of tumor invasion, and lymph node metastasis. Two radiologists assessed preoperative CT and/or MRI for the primary tumor site detectability, the presence or absence of regional lymph node, and the size of the largest lymph node. Demographic, imaging, and pathologic findings were compared between the two groups of patients based on pathologic lymph node metastasis and optimal size criterion was obtained.RESULTS: The locations of tumor were ascending, transverse, descending, sigmoid colon, and rectum. One hundred and sixty early colorectal cancers were classified into 3 groups based on the pathological depth of tumor invasion; mucosa, submucosa, and depth unavailable. A total of 20(12.5%) cancers with submucosal invasion showed lymph node metastasis. Lymph nodes were detected on CT or MRI in 53 patients. The detection rate and size of lymph nodes were significantly higher(P = 0.000, P = 0.044, respectively) in patients with pathologic nodal metastasis than in patients without nodal metastasis. Receiver operating curve analysis showed that a cut-off value of 4.1 mm is optimal with a sensitivity of 78.6% and specificity of 75%.CONCLUSION: The short diameter size criterion of≥ 4.1 mm for metastatic lymph nodes was optimal for nodal staging in early colorectal cancer.

Primary signet ring cell carcinoma of the appendix:A rare case report and our 18-year experience

Primary adenocarcinoma of the appendix is a rare ma-lignancy that constitutes < 0.5% of all gastrointestinal neoplasms. Moreover, primary signet ring cell carci-noma of the appendix is an exceedingly rare entity. We have encountered 15 cases of primary appendiceal cancer among 3389 patients who underwent appen-dectomy over the past 18 years. In the present report, we describe a rare case of primary signet ring cell carcinoma of the appendix with ovarian metastases and unresectable peritoneal dissemination occurring in a 67-year-old female patient. She underwent ap-pendectomy and bilateral salpingo-oophorectomy with a laparoscopy procedure. She then received palliative systemic chemotherapy with 12 cycles of oxaliplatin, 5-flurorouracil, and leucovorin (FOLFOX-4). The patient currently is well without progression of disease 12 mo after beginning chemotherapy.

Prognostic value of 18-fluorodeoxyglucose positron emission tomography-computed tomography in resectable colorectal cancer

AIM:To assess the prognostic value of preoperative 18 fluorodeoxyglucose positron emission tomography(FDG-PET)/computed tomography(CT) in patients with resectable colorectal cancer.METHODS:One hundred sixty-three patients with resectable colorectal cancer who underwent FDG-PET/CT before surgery were included.Patient data including pathologic stage at presentation,histology,treatment,disease-free survival and the maximum standardized uptake value(SUVmax) of the primary tumor on FDG-PET/CT were retrospectively analyzed.Median follow up duration was 756(range,419-1355).The primary end point was disease-free survival.RESULTS:Twenty-five of 163 patients(15.3%) had recurrences.The median SUVmax values of the recurrence and no-recurrence groups were 8.9(range,5-24) and 8.2(range,0-23,P = 0.998).Receiver operating characteristic(ROC) curve analysis showed no significant association between SUVmax and recurrence(area under the curve = 0.5,P = 0.998,95% CI:0.389-0.611).Because a statistically significant value was not found,SUVmax was dichotomized at its median of 8.6.The disease-free survival curve was analyzed using the median SUVmax(8.6) as the cut off.Univariate and multivariate analysis did not provide evidence that disease-free survival rates for the subgroups defined by the median SUVmax were significantly different(P = 0.52,P = 0.25).CONCLUSION:Our study suggests that the high FDG uptake of primary mass in resectable colorectal cancer doesn't have a significant relationship with tumor recurrence and disease-free survival.