Combined positron emission tomography and computed tomography (PET/CT) is currently widely used in the clinical diagnosis of cancer to provide functional and morphological imaging. The value of PET/CT in detection of the recurrence and metastasis of colorectal cancer (CRC) was recently confirmed in an article appearing in the October 7 issue of the World Journal of Gastroenterology.
The research performed at the Department of Medical Oncology, Jinling Hospital, China. Dr. Chen and his colleagues observed a total of 68 postoperative CRC patients, 48 male and 20 female, who were examined in the Jinling Hospital PET/CT Center between August 2004 and August 2006. After PET/CT imaging, recurrence and/or metastasis were confirmed in 82.4% (56/68) of the patients, with 91.7% (22/24) cases with elevated serum CEA levels. PET/CT detected more lesions than CT or ultrasonography alone in 30.4 % (17/56) of the cases of recurrence and/or metastasis.
CRC is the most common gastrointestinal malignancy, and its incidence and mortality are rising in China. Radical resection remains as the major means of CRC management, but recurrence and/or metastasis occurs in 30 to 50 percent of patients after surgery. An accurate diagnosis of postoperative local recurrence and distant metastasis is crucial for prescribing optimal individualized management and thus elevating the survival rate. However, CRC is not normally detected by traditional imaging techniques, such as CT, magnetic resonance imaging (MRI) and ultrasonography, until the lesion reaches a considerable size.
PET/CT imaging provides a whole-body overview in one examination, and can detect abnormal glucose metabolism before the morphological changes of a lesion can be identified. In the current study, the treatment plans of 16.2% (11/68) of the cases were altered based on the PET/CT findings. Local metastasis focus was detected in the liver or lung in three cases; accordingly surgical resections were conducted instead of intravenous chemotherapy. Conversely, disseminated metastases were detected in six cases, and thus intravenous or oral chemotherapy was prescribed instead of surgery.
To most CRC patients, the cost of PET/CT is more expensive than traditional imaging techniques. However, Dr. Chen believes an optimal, individualized treatment plan is the most important aspect of treating this malignancy, as such a plan can indeed prolong the life and lessen both the mental and economical burdens of patients.
The researchers demonstrated the superiority of 18F-DG PET/CT in the imaging diagnosis of the postoperative recurrence and/or metastasis of CRC by conducting a retrospective study of 68 patients. Their findings are valuable when considering the choice of imaging techniques for detecting the recurrence and/or metastasis of CRC.
Reference: Chen LB, Tong JL, Song HZ, Zhu H, Wang YC. 18F-DG PET/CT in detection of recurrence and metastasis of colorectal cancer. World J Gastroenterol 2007; 13(37): 5025-5029
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