Patient case: 35-year-old female with Colorectal cancer. Genetic variant: FGFR1 Amplification. Other conditions: None.

Clinical trial: PET Evaluation of Response After 1 Course of Chemotherapy as Predictor of Treatment Outcome.

Summary: Study hypothesis : early decrease in fdg-pet measured SUV max after 1 cycle of chemotherapy can accurately predict response of chemotherapy as assessed by conventional radiology after 3 cycles of chemotherapy.
  FDG-PET imaging will be done at J0 and J14 of a new line of chemotherapy treatment in metastatic colorectal cancer.
  SUV max will be recorded and delta SUVmax will be compared to the results of conventional radiological evaluation after 3 courses of chemotherapy. Results will also be compared to the time to disease progression.

Detailed description: statistical hypothesis : Sample size calculation for FDG-PET in metastatic patients.
  In the paper of Cascini et al. [1], they have 18 patients with a TRG response (TRG = Tumor Regression Grade) and 15 patients with no response.
  SUV mean was measured at baseline and at day 12 in all 33 patients. All 33 patients showed a reduction in SUV-mean from baseline to day 12. The median reduction in SUV-mean was 63% (mean 66%) in responding tumors and 22% (mean 22%) for non responding tumors. Using a cutoff level of 52% a perfect accuracy could be obtained, i.e. all responding tumors had a SUV-mean reduction higher than 52% and all non responding tumors had a SUV-mean reduction lower than 52%.
  (Standard deviation of the SUV-mean reduction was 25.) All 33 patients showed also a reduction in SUV-max from baseline to day 12. The median reduction in SUV-max was 62% in responding tumors and 28% in non responding tumors. (No information about mean or standard deviation of SUV-max available in [1].) Based on the data of SUV-mean we can do a power calculation based on the Wilcoxon test: In order to demonstrate an absolute difference in the mean of ΔSUV-mean of 44% between responding and non responding patients, with an estimated standard deviation of 25, using 35 patients (50% response, 50% no response), at a significance level of 5%, we obtain a power of 0.98.
  For SUV-max, if we assume that the difference in the means is similar to the difference in the medians, i.e. 34% and the standard deviation is similar to the one of SUV-mean, i.e. 25, we obtain a power of 0.93 If we, to be safe, are a little bit less optimistic and estimate that the difference in the mean of ΔSUV-max between responding and non responding tumors would be a little lower than in [1]: 35%, and the standard deviation a little bit higher: 30, then we need 40 patients at a power of 0.90
  Référence 1 : Cascini GL, Avallone A, Delrio P, Guida C, Tatangelo F, Marone P et al.: F-18-FDG PET is an early predictor of pathologic tumor response to preoperative radiochemotherapy in locally advanced rectal cancer. Journal of Nuclear Medicine 2006, 47: 1241-1248.

Eligibility: Inclusion Criteria:
  -  advanced colorectal cancer
  -  evaluable disease
  -  signed informed consent
  Exclusion Criteria:
  -  no other cancer
  -  no other life-threatening condition
  -  unwillingness or inability to sign informed consent
  -  active cerebral metastasis

Relevance to patient case: not relevant