Possible Role of FDG-PET in the Early Prediction of Therapy Outcome in Liver Metastases of Colorectal Cancer

Abstract

Nonresectable colorectal cancer metastases in the liver respond to chemotherapy in 20-25% only. Early identification of nonresponders might allow the use of other regimens. In a limited feasibility study, it should be determined whether (a) a single high-dose chemotherapy application has an early effect on glucose-utilization, detectable and quantitatable by noninvasive positron emission tomography using [18F]-Fluoro-deoxyglucose (FDG-PET) and (b) assess its value as a predictor of the final therapeutic outcome. A total of 10 patients with documented nonresectable liver metastases of a colorectal cancer were studied by FDG-PET, prior and 72 h after a single infusion of 5-Fluorouracil and Folinic acid (5-FU/FA). Glucose utilization was quantitated by determination of standard-uptake values and correlated with final therapy outcome following completion of the anticipated therapy cycle. Patients were followed up for at least 6 months. All metastases responding to therapy (n = 6) exerted a statistically significant decrease of FDG uptake (-22+/-10%), metastases (n = 2) showing a short-term effect (duration of tumor reduction <3 months) had a slightly diminished, and progressing metastases (n = 3) an enhanced FDG uptake (13+/-17%). Our preliminary data indicate that acute changes of glucose utilization-as detected by FDG-PET-following a single application of chemotherapy, seems to be indicative for the final therapeutic outcome, at least in liver metastases of colorectal cancer.

Time‐course of effects of external beam radiation on [18F]FDG uptake in healthy tissue and bone marrow

“…In many studies, early metabolic changes measurable by [${}^{18}\mathrm{normalF}$]FDG‐PET were highly predictive of clinical responses observed weeks to months later. Such findings have been reported for a variety of cancers, including lymphoma, as well as breast, esophageal, gastric, colorectal, head and neck, and non‐small‐cell lung cancers 5 , 16 . Early declines in [${}^{18}\mathrm{normalF}$]FDG uptake generally correlate with longer progression‐free and overall survival.…”

Monitoring and Predicting Response to Therapy with 18F-FDG PET in Colorectal Cancer: A Systematic Review

“…Reference standards for the serial 18 F-FDG PET studies were the clinical response data, according to the World Health Organization (WHO) classification. In contrast to the studies of Findlay et al (10) and Bender et al (11), that study investigated absolute standardized uptake values (SUVs) and kinetic parameters and not fractional changes between baseline and follow-up scans. Even the quantitative values from the first PET study (at baseline) were predictive with respect to therapy outcome.…”

“…Five studies (Table 1) reported the predictive value of 18 F-FDG PET in patients treated with chemotherapy for nonresectable colorectal cancer liver metastases (10)(11)(12)(13)(14). As early as 1996, Findlay et al (10) studied 18 patients before, at 1-2 wk after, and at 4-5 wk after 5-fluorouracil (5-FU) chemotherapy with or without interferon-a by using a nondedicated PET system with a limited resolution.…”

“…Bender et al (11) showed that the flare phenomenon probably does not play a role as early as 72 h after the initiation of chemotherapy. Their preliminary results demonstrated that therapy-sensitive metastases show a reduc- tion in 18 F-FDG uptake after a single application of chemotherapy and that this effect can be quantified by PET and seems to be indicative of the final therapy outcome after the completion of an anticipated therapy cycle.…”

Assessment of Response to Therapy

“…In these cases early identification of nonresponders might allow the use of other regimens (de Geus-Oei et al 2009;Bender et al 1999). 18F-FDG PET has emerged as a promising diagnostic modality, not only for staging and re-staging of colorectal cancer (Fig.…”