Water molecule movement may be the key to monitoring success of ovarian cancer treatmentBMJ 2012; 344 doi: http://dx.doi.org/10.1136/bmj.e1229 (Published 20 February 2012) Cite this as: BMJ 2012;344:e1229
Magnetic resonance imaging (MRI) that measures the movement of water molecules in tumours may be the best way to monitor the response to treatment of women with advanced ovarian cancer, shows a study that compares different types of imaging in this group of patients.
The study compared three different MRI techniques and found that diffusion weighted MRI was the most effective for detecting the effects of treatment on primary ovarian tumours and on tumours that had metastasised to surrounding tissues (Radiology doi:10.1148/radiol.11110175).
Computed tomography has traditionally been used to assess whether patients with ovarian cancer should continue with chemotherapy after their first round of treatment. But this type of scanning measures changes only in the size of tumours, not in their structure.
Serum CA-125, a cell surface protein that is increased in ovarian cancer, is also used as a biomarker of overall response to treatment, but it integrates responses from responding and non-responding tumours in patients with multiple sites of disease.
“At the moment we rely on CT scans and blood tests to tell us what’s going on inside a patient’s tumour,” explained Evis Sala, lecturer in radiology at the University of Cambridge and the study’s lead author. “But it’s difficult to judge how effective treatment has been from these alone, particularly when the cancer has spread to other tissues where it may behave differently from the primary tumour,” she added.
The lack of reliable methods for assessing response to treatment has made it difficult to accurately monitor the effects of treatment in women with ovarian cancer and to decide whether it would be beneficial to continue treatment. Molecular differences between primary ovarian tumours and metastatic disease that affect response to treatment mean that it is also important to monitor what happens to tumours at different sites.
Researchers from Addenbrooke’s Hospital, Cambridge, compared three types of imaging in assessing the primary ovarian mass and tumours at two distant sites in 21 women with advanced ovarian cancer being treated with platinum based chemotherapy.
The three methods they compared were diffusion weighted MRI (which measures the movement of water molecules in tissues), dynamic contrast material enhanced MRI (which uses a contrast agent to make tissues easier to see), and hydrogen-1 MR spectroscopy.
Results showed that diffusion weighted MRI was the most effective imaging technique for detecting responses to treatment and differentiating between responses in primary tumours in the ovary and those at distant sites.
“We’ve shown that diffusion weighted MRI can give a much better idea of the density of tumours, in addition to their size, making it easier to determine which patients are benefiting most from the treatment,” said Dr Sala.
The group concluded that the combination of robustness, non-invasiveness, and extensive anatomic coverage may make diffusion MR imaging the most appropriate imaging modality for monitoring response to neoadjuvant platinum based chemotherapy in patients with advanced ovarian cancer.
“We are now collaborating on a nationwide study to see if this type of imaging could be an effective way of predicting treatment response in a much larger group of patients with advanced ovarian cancer,” Dr Sala concluded.
Cite this as: BMJ 2012;344:e1229