A simple test using a magnetic resonance imaging (MRI) scan may be used to predict how well people with advanced epithelial ovarian cancer will respond to treatment, according to the results of a new study published by Winfield et al in Radiology. In a large clinical trial, scientists have shown a new way to assess how well treatment is working and give an indication of its future effectiveness, which may help optimize outcomes in patients who are at a high risk of relapse after receiving treatment or who have already relapsed and are receiving second-line treatment.

Study Background

In the study, scientists used a measurement called the apparent diffusion coefficient, which is a calculation that describes the distances diffused by water molecules within tissues over time.

Water molecules are restricted from moving by structures in their vicinity, such as cell membranes. Measuring how much or how little the water molecules are restricted may provide information about the structure of tumor tissue.

Study author Nandita deSouza, MD, Professor of Translational Imaging at The Institute of Cancer Research, London, and Clinical Consultant in Imaging at The Royal Marsden NHS Foundation Trust, said, “The apparent diffusion coefficient gives a picture of what is going on across an entire lump of tumor, and at each tumor site, rather than just one small sample from a single site, like in a biopsy. These data can be used as an imaging marker and can be related to the microstructure of the tumor. The measurements also allow us to make judgements about how the tumor is responding. We can relate changes we see over time on the scans to the responses of patients and their likelihood of surviving without progression of their disease.”

Patients included in this trial had either high grade serous, endometrioid, or clear cell ovarian, primary peritoneal, or fallopian tube cancers, with at least one solid lesion measuring larger than 2 cm.

Two cohorts of patients were recruited; those in cohort 1 had newly diagnosed disease, while those in cohort 2 were on their first or subsequent relapse of the disease. Patients in the newly diagnosed cohort had an MRI within 7 days before starting treatment. Patients were treated with three cycles of chemotherapy and scanned again, prior to surgical resection. Patients in the relapsed cohort had an MRI within 7 days before starting treatment, and another scan after one and after three cycles of chemotherapy.

In both cohorts, the response to treatment was assessed by checking levels of cancer antigen 125, or CA125, and using radiologic scans.

Results

Data were analyzed from 125 women in total: 47 newly diagnosed women in cohort 1 and 78 women with relapsed disease in cohort 2. 

Analysis of all the scan data, combined with other key clinical data, showed that patients with epithelial ovarian cancer who were responding to treatment with chemotherapy had a higher apparent diffusion coefficient than patients who were not responding.

After three cycles of platinum-based chemotherapy, changes to the apparent diffusion coefficient gave an indication of whether or not the patient was responding to the treatment. In patients with relapsed disease, an increase in the apparent diffusion coefficient after one treatment cycle indicated that a patient was likely to have improved progression-free survival. Apparent diffusion coefficient change was not indicative of overall survival in either cohort.

Study author Emma Hall, PhD, Deputy Director of Clinical Studies at the Institute of Cancer Research Clinical Trials and Statistics Unit, said, “The data from this trial are useful to add to the toolbox of markers we use to predict patient outcomes. We weren’t able to find an association between the apparent diffusion coefficient and a patient’s overall survival, but there is a link to progression-free survival. From our study, we can see that the apparent diffusion coefficient increases more in patients whose cancer is responding to treatment compared to those whose cancer is not responding. This indicates changes to the microstructure of the tumor, and these changes are detectable very early on in treatment.”

“In future, this could mean we could make changes to a patient’s treatment earlier in the process, if we have signals that their cancer is not responding,” she concluded.

Disclosure: For full disclosures of the study authors, visit pubs.rsna.org.