Z Gastroenterol 2006; 44 - A99
DOI: 10.1055/s-2006-943465

The early judgement of the efficacy of the applied chemotherapy in metastatic colorectal cancer with PET

Á Petrányi 1, Z Lengyel 2, E Vegh 1, K Tamas 1, Z Szucs 1, Z Arányi 1, G Bodoky 1
  • 1Szent László Kórház
  • 2Pozitron Diagnosztika Kft

Objectives: The PET-CT is a widely used imaging method in the well developed countries, and it is getting more and more available in Hungary as well. We want to determine whether the PET is appropriate in early judgment of the efficiency of chemotherapy in metastatic colorectal cancers.

Methods: Since 15 July 2005, we have examined 20 patients with histologically proven colorectal carcinoma of having at least one hepatic metastasis which could be well visualized also with CT scan. We compared the SUV values before and after the first two cycles of irinotecan + de Gramont chemotherapy. The changes of the values were analyzed in order to estimate the efficacy of the chemotherapy. The results were compared with the findings of the long term radiological examination or in case of surgical interventions with the pathological results.

Results: The study is still going on. We observed that the SUV values were decreasing in 13 cases out of 20. In these cases the CT examination confirmed the partial regression (PR). In 3 cases the SUV value did not change significantly. The CT examination indicated regression (PR) in 2 and progression (PD) in 1 case. In 4 further cases the SUV values increased, 1 patient out of these died before the control, one showed stable status (SD) according to the CT scans and in 2 cases progression (PD) was detected. In few cases, the PET examination has helped us to detect some formerly not-known distant metastases.

Conclusion: The data suggest that if the SUV values of the PET examination are decreasing right after the chemotherapy, the tumor tissue is sensible to the applied chemotherapy; if the SUV values are increasing, the tumor is chemotherapy resistant. The PET examination accomplished in due time allows to judge the efficiency of the chemotherapy after the first cycle, and helps to make decision whether to continue the current therapy, or to change the cytostatic regimen, or to suggest immediate surgical intervention.