ROLE OF FDG PET-CT IN COMPARISON WITH ENHANCED CT IN DETECTION OF POST THERAPEUTIC COLORECTAL CANCER RECURRENCE AND METASTASIS
Colorectal cancer is a major cause of morbidity and mortality throughout the world. It accounts for over 9% of all cancer incidence. It is the third most common cancer worldwide and the fourth most common cause of death. It affects men and women almost equally (Fatima and Robin, 2009).
Despite optimal primary treatment, with adequate surgery with or without adjuvant chemotherapy, 30%–50% of patients with colon cancer will relapse and die of their disease. The principal aim of follow-up programmes after curative resection of colorectal cancer is to improve survival (Gan et al., 2007).
Early detection of recurrence is clinically important and can improve the prognosis and survival of patients with cancer. CT is considered the primary method of investigation because of its low cost, widespread availability, and high-resolution of anatomic details, but may under-estimate the actual tumor burden by overlooking small tumor clusters in areas of distorted anatomy after treatment. (Israel and Kuten ,2007).
Cancer-related metabolic abnormalities usually precede structural changes and are readily detected by PET. PET is a highly sensitive imaging test for the detection of occult recurrences, such as those seen in colorectal cancer (Israel et al., 2011).
Accurate imaging of patients with possible recurrent colorectal cancer (CRC) is vital, as it is now clear that curative surgery is still possible for a proportion of patients with metastatic disease. Follow-up is usually performed with carcinoembryonic antigen (CEA) level, computerized tomography (CT) and other conventional imaging techniques, but in the last few years, functional imaging using integrated positron emission tomography and CT (PET/CT) is being used increasingly to identify recurrent disease (Mittal et al., 2011).
AIM OF THE WORK
AIM OF THE WORK
The goal of this study is to elucidate the role of 18F-FDG PET-CT in comparison with enhanced CT for detection of post therapeutic colo-rectal cancer recurrence and metastasis
Review of literature
The large intestine is a long muscular tube which starts from the caecum down to the rectum with approximately 1.5 m in length. The colon has three longitudinal muscle layers (taena coli) that converge on the appendix proximally and the rectum distally, both of which have a complete muscular coat. The taena coli are about 30 cm shorter than the colon, giving sacculations (haustra) (Khan ,2012).
Fig.1: Anatomy and relations of colonic segments
(Quoted from Bharwani and Reznek , 2011).
Fig.2: The extension and relations of the cecum (Quoted from Netter, 2014)
It is an intraperitoneal blind ended “pouch-like” structure situated in the right iliac fossa bounded to the abdominal wall by the cecal peritoneal folds. The cecum measures about 7.5 cm and connects the ileum to the large intestine by an invagination known as the ileocecal valve. The vermiform appendix arises from the posteromedial aspect of cecum about 3.5 cm from the ileocecal valve (Netter, 2014).
The ileum …
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