Level of tumor brightness predicts cervical cancer survival
Patient age at diagnosis, tumor volume and stage, and histology are the usual factors that are used to predict survival from cervical cancer. However, researchers from Washington University School of Medicine in St. Louis have discovered that these characteristics seem to have less association with prognosis and outcome than does the level of brightness detected from a glucose tracer in a PET scan.
As reported in the Oct. 15 issue of Cancer, Dr. Elizabeth A. Kidd and her colleagues used PET to evaluate the amount of cervical tumor uptake of F-18 fluorodeoxyglucose (FDG) — a radiolabeled gluocose tracer — and its association with treatment response and prognosis.
Two hundred eighty-seven patients with varying degrees of cervical cancer received FDG-PET or -PET/CT before cervical cancer treatment (surgery, chemotherapy or radiation therapy) and three months after treatment. For each PET evaluation, the researchers measured the maximal standardized uptake value for FDG in the primary tumor. The higher the standardized uptake, the brighter the signal appeared on the screen. They also measured the PET tumor volume to see the difference in association.
Patients were examined every two months for the first six months, every three months for the next two years and every six months after that. On average, the last follow-up was at 32 months.
The researchers discovered that patients with higher standardized uptakes of the glucose tracer were more likely to have aggressive cancers. They also found that the amount of glucose uptake was not related to tumor volume, meaning that a larger tumor did not necessarily mean a more aggressive cancer. After analyzing for associations between overall survival rate and other patient-specific characteristics, such as tumor histology and lymph node status, they found that the maximal standardized uptake value was the only significant independent predictor of death from cervical cancer.
The five-year survival rate for patients with a low standardized uptake was 95 percent (30 patients); for those with a middle-ranged standardized uptake, it was 70 percent (160 patients); and for those with a high uptake, it was 44 percent (70 patients).
The researchers concluded that the maximal standardized uptake value of FDG may be a good indicator of the treatment response and overall survival rate for patients with cervical cancer.
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