The value of abdominal CT scans in decision-making during chemotherapy in ovarian cancer

During chemotherapy of ovarian cancer many CT scans are performed to assess tumor response during treatment. The aim of this study was to determine the value of abdominal CT scan in the decision to continue chemotherapy or not, after the standard six cycles.

All ovarian cancer patients diagnosed between 1991 and 1997 were retrospectively included in the study. Clinical parameters, surgical results, diagnostic test results, and therapeutic strategies were collected from medical records. With logistic modeling those parameters were chosen that predicted best the chance of receiving additional chemotherapy. The chance of receiving further chemotherapy after six cycles based on these parameters was computed and compared to the chance based on CT scan results in addition to these parameters. Arbitrarily we defined a change of over 20% as meaningful.

Eighteen of 50 included patients (36%) received over six cycles of chemotherapy; 29 patients (10%) were at low risk for receiving over six cycles, because they had an optimal debulking surgery and low levels of CA-125 at cycle six. The chance of receiving continued chemotherapy after taking into account positive tumor signs on CT-scan was 22%. This figure further increased to 33% if tumor presence was based on judgment of two CT scans. High-risk patients were patients with suboptimal debulking surgery or patients with an optimal debulking, but high CA-125 levels at cycle six (n = 21). Based on these parameters their chance of receiving additional chemotherapy was 71%, and after taking into account results of one or two CT-scans, the risks increased to 74% and 81%, respectively.

CT scans are of no value in deciding the number of chemotherapy cycles in the initial treatment for ovarian cancer. They cost a lot of money, can add a lot of confusion, and offer no benefit over results of debulking surgery and CA-125 levels.