A new model of rectal cancer with regional lymph node metastasis allowing in vivo evaluation by imaging biomarkers.

OBJECT: The work is aimed to develop a murine model of rectal cancer, which could be used to monitor lymph node metastasis development by magnetic resonance imaging (MRI) and optical imaging (OI) techniques. SUBJECTS AND METHODS: Ht-29 cancer cells were directly injected into the submucosal layer of the rectum of athymic nude mice using trans-anal rectal cancer cell injection (TARCI). Thirty-six mice were inoculated with 10×10(5) cells and five mice were treated with sterile phosphate buffer solution. One to 4 weeks after cell injection, tumor growth was evaluated in vivo using T2-weighted MRI at 4.7T. A further group of animal (n=6) treated with ht-29_luc cells, with the same protocol, was monitored by optical imaging. In both groups, the presence of the primary tumor and of lymph nodes metastasis was confirmed by histology. RESULTS: In all animals, primary tumors were detectable by MRI, 1 week from TARCI. After 4 weeks primary tumors showed a mean longitudinal diameter of about 2cm. All animals developed regional lymph node metastases. Others organs (e.g. lung or liver) were not affected. In fat-suppressed, T2-weighted MRI, lymph nodes appeared as small areas characterized by hyper-intense signal compared to muscle. OI permitted evaluation of the primary tumor growth in perineal region. CONCLUSIONS: TARCI of ht-29 cells into the rectum of nude mice is a feasible way to obtain a easily reproducible model of regional lymph node metastases could be monitored by magnetic resonance and optical imaging techniques.

Treatment of abdominal aortic aneurysm associated with colorectal cancer: presentation of 14 cases and literature review.

PURPOSE: The coexistence of abdominal aortic aneurysm (AAA) and cancer is observed with increasing frequency, raising several questions about therapeutic and surgical strategies for management of both diseases. In this study, we present our experience on 14 patients affected by both colorectal cancer (CRC) and AAA, and we have also reviewed the literature from 1988 to 2005 for clinical experiences on this matter. MATERIALS AND METHODS: From January 1988 to May 2006, 1,012 AAA and 1,480 CRC were observed and treated in our department; in 14 patients (1.3% of AAA and 0.9% of CRC), both diseases were coexistent. We also performed a literature review from 1987 to 2005, and we found 254 cases of AAA associated with CRC. RESULTS: Priority was given for treatment of vascular disease. The diseases were treated in one stage in nine cases and in two stage in four patients; in the remaining case, only the CRC was treated due to patient's poor cardiac conditions. Postoperative (30-day) complications were seen in 1 of 14 patients (7.1%), whereas there were no postoperative deaths or prosthetic infections. In the literature review, treatment in one stage was performed in 102 cases and in two stage in 118 cases; in the remaining 25 cases, only one disease was treated (in 24 cases, for different reasons, only CRC was treated, whereas in the last case, only the AAA was treated, and the patient died in the postoperative period). Postoperative (30-day) morbidity and mortality in one-stage treatment were 8 and 4.5%, respectively, and 21.3 and 6% in two-stage treatments, respectively. In patients treated for only one disease, 30-day morbidity and mortality were 4 and 24%, respectively. Only one case of prosthetic infection was reported after a two-stage treatment. CONCLUSIONS: From the analysis of the literature and our experience, it is evident that, when AAA and CRC are coexistent with preoperative diagnosis of both diseases, single-stage intervention, when feasible for patient in general and local conditions, has to be preferred due to the lower morbidity. Single-stage treatment avoids a second surgical and anesthesiologic trauma and eliminates the risks joined with the non-treated lesion, increasing, however, the magnitude of the operation. Endovascular therapy, for its less invasiveness, appears to be an adequate solution for one-stage treatment of the two diseases but its role is still subject of ongoing discussions.