Molecular Imaging Insight - March 2008 - (Page 11) PET/CT Oncology Relative changes in tumor FDG evaluation does not address initial uptake on PET and size from the response to treatment or early detecbaseline to the follow-up scan were tion of disease recurrence. calculated on CT by two different According to a study published in observers, blinded to one another’s the Nov. 21, 2007 issue of the Journal findings. Their accuracy for assessof the American Medical Association, ment of histopathologic response was the use of metabolic imaging with compared by receiver operating charFDG-PET in the follow-up of paacteristic curve analysis. tients treated for advanced cervical The researchers found that changes cancer can lead to earlier detection of in tumor size were not significantly corcancer recurrence. related with histopathologic response. Although the development of the “Using standard size criteria for evalhuman papilloma virus (HPV) vacuation of tumor response (RECIST), cine has the potential to significantly only 25 percent of the histopathologireduce de novo HPV infection in cally responding tumors were identified women younger than 26 years, a sigSarcoma arising in the psoas muscle near the spine and in the current study, the authors wrote. pelvis. Source: Apollo Hospitals, Hyderabad, India. nificant population of women remains “By comparison, metabolic changes corat risk for future development of cerrectly identified all of the histopathologic responders and 71 percent vical cancer, according to the authors. of the histopathologic non-responders. These striking differences Researchers at Washington University School of Medicine in suggest that in high-grade, soft-tissue sarcoma, response assessment St. Louis performed pre- and post-treatment FDG-PET/CT on according to RECIST is of limited value and should be complement92 patients diagnosed with cervical cancer from Jan. 1, 2003 ed by imaging of tumor metabolic activity with FDG-PET.” through Sept. 1, 2006. Post-therapy PET scans were performed, The scientists noted that although the study is encouraging, it on average, three months after treatment. is difficult to draw definitive conclusions because response “The three-month, post-therapy FDG-PET provided an immeassessment by CT or magnetic resonance imaging was not done diate measure of response to therapy and was a robust predictor of in parallel with the FDG-PET studies. However, the results clearoutcome to treatment for cervical cancer,” the authors reported. ly demonstrate that FDG-PET should be employed as a modality “If this finding is verified by others, we recommend designing to monitor treatment response in soft-tissue sarcoma patients. clinical trials to explore novel therapies for patients with either “This prospective study shows that a change in tumor glucose partial metabolic response or progressive disease on post-therametabolic activity is a significantly more accurate parameter py FDG-PET,” the authors suggested. than a change in size at assessing histopathologic response to neoadjuvant therapy in patients with high-grade, soft-tissue sarCoLoN CANCER coma,” the authors wrote. Staging Pathways in Recurrent Colorectal Carcinoma: CERviCAL CANCER Association of Posttherapy Positron Emission Tomography With Tumor Response and Survival in Cervical Carcinoma JAMA, November 21, 2007—Vol 298, No. 19 Cervical cancer, one of the three most prevalent cancer diagnoses in women worldwide, presents challenges to clinicians in treatment and follow-up. For patients presenting with the disease, approximately one-third will develop disease recurrence after therapy. Unfortunately, the current guideline for post-therapy MolecularImaging.net is Contrast-Enhanced 18F-FDG PET/CT the Diagnostic Tool of Choice? J Nucl Med 2008; 49:354–361 The utilization of FDG-PET for the evaluation of recurrent colorectal carcinoma has found widespread acceptance; however, in clinical practice the use of contrast-enhanced CT is still the modality of choice for a first-line re-staging tool. A team of Swiss researchers found that contrast-enhanced PET/CT provides higher accuracy and leads to greater therapeutic impact for restaging colorectal cancer patients, in results published in the March 2008 | Molecular Imaging Insight 11 http://www.ncbi.nlm.nih.gov/pubmed/18287263?dopt=Abstrac http://jama.ama-assn.org/cgi/content/abstract/298/19/2289 http://MolecularImaging.net
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