(TORONTO, Canada, Sept. 14, 2018) - An Ontario clinical study that shows adding PET imaging to conventional CT imaging to stage locally advanced cervix cancer can change treatment means newly diagnosed women in this province may also receive PET imaging.

The findings are published online today by JAMA Network Open. Co-principal investigators Dr. Anthony Fyles, radiation oncologist at Princess Margaret Cancer Centre, and Dr. Lorraine Elit, gynecologic oncologist at Hamilton Health Sciences' Juravinski Cancer Centre, explain:

"We met our goal of determining whether adding PET detects more extensive disease and influences treatment. The study showed that patients who had PET were twice as likely to have a change in their treatment."

Locally advanced cervix cancer - about 40-50 per cent of all cervix cancers - is inoperable, but potentially curable with chemotherapy and radiation therapy. Women eligible for PET have involved or suspicious lymph node metastases on CT, in which case PET can show additional nodal disease not seen on CT.

Dr. Fyles, also Professor, Radiation Oncology, University of Toronto, says: "With PET we always learn more about disease, but does that knowledge change what we do in treating patients? In this instance it did and it's extremely gratifying to provide new evidence that changes clinical practice."

Dr. Elit, Professor of Obstetrics and Gynecology, McMaster University, Hamilton, says: "This trial was a team effort. It is an example of how physicians who treat women with cervical cancer can work together to carry out a high-quality study, the results of which ultimately change practice in our province. As a result of our research, the access to PET scans for women with this disease has expanded in Ontario."

Study author Dr. Mark Levine, Professor of Oncology, and Director, Ontario Clinical Oncology Group (OCOG) at McMaster, adds that although previous studies showed PET could detect more tumour than usual tests, the Ontario randomized trial is the first to evaluate whether PET leads to a change in clinical management.

From 2010-2014, the study, co-ordinated by OCOG and funded by Cancer Care Ontario, enrolled 171 women at six regional cancer centres - the Princess Margaret, Odette Sunnybrook, Juravinski, London, Ottawa and Thunder Bay.

Study participants were over 18 and newly diagnosed. Half the women received a CT, which shows abnormalities or disease in the body area scanned. The other half received a CT plus a PET scan, which reveals "hot spots" of cell activity or growth that can indicate cancer. About twice as many women in the PET arm received more extensive radiation.

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The research was funded by Cancer Care Ontario.

About Princess Margaret Cancer Centre, University Health Network