Gynecologic Cancers: Where Molecular Imaging Makes a Difference

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Patricia Eifel, MD, ASTRO President and Professor of Radiation Oncology at MD Anderson Cancer Center

Molecular imaging, particularly PET/CT, shows promise in improving staging and monitoring of cervical cancer patients. In anticipation of the 50th annual ASTRO meeting, Patricia Eifel, MD, ASTRO president and professor of radiation oncology at MD Anderson Cancer Center in Houston, offers insight into current protocols, potential impacts and impediments to routine clinical use of PET/CT in cervical cancer care.

Eifel’s clinical practice and research is focused exclusively on the treatment of gynecologic malignancies. At MD Anderson, the gynecologic cancer treatment arsenal consists of advanced radiation therapy techniques, including intensity modulated radiation therapy, 3D conformal therapy, intraoperative electron beam therapy and brachytherapy. Increasingly, Eifel and her colleagues tap into PET/CT to improve clinical treatment of patients with cervical cancer.

MII: Can you provide an overview of the circumstances under which a patient is referred for molecular imaging?

Eifel: At MD Anderson, we routinely refer cervical cancer patients for PET/CT studies. A number of studies demonstrate the utility of PET/CT in gynecologic cancers, particularly cervical cancers. PET/CT is useful both for upfront staging to evaluate potential sites of disease and for follow-up therapeutic monitoring. Ideally, patients undergo at least one PET/CT follow-up three months after therapy. The second scan helps physicians determine the patient’s response to radiation treatment.

MII: Does molecular imaging bridge any gaps in cervical cancer imaging?

Eifel: PET/CT is the most accurate non-invasive test to image cervical cancer. All of the other non-invasive tests are less accurate than PET/CT. Other non-invasive studies evaluate the size of the lymph nodes to estimate the extent of disease. It’s well-known that this method is not sufficiently accurate. PET/CT, on the other hand, is very accurate, indicating with greater sensitivity whether or not lymph nodes are involved in the malignancy.

MII: How can molecular imaging make a difference in caring for women with gynecologic cancers?

Eifel: In many cases, the results of the PET study direct physicians toward potential sites of disease that are very difficult to find with other imaging studies. Physicians use the PET data to inform and, often change, treatment and management of the disease.

MII: Do you see greater adoption and more widespread use of PET/CT in gynecologic cancers in the future?

Eifel: Multiple studies indicate the utility of PET/CT for staging and monitoring of cervical cancer. Other studies show that the technology plays a key role in treatment planning by identifying sites of active disease. This information helps us determine where to target the highest radiation dose. In the future, PET/CT will be increasingly used in treatment planning.

In addition, researchers are still defining the role of PET/CT in follow-up of cervical cancer patients. Researchers are attempting to determine the frequency of follow-up PET/CT studies. Overall, there is a lot of opportunity for PET/CT in the cervical cancer treatment program. It is a very useful tool in our field.

MII: Can you describe any impediments to full adoption of molecular imaging technology in cervical cancer?

Eifel: The primary impediment is cost. PET/CT is not always reimbursed by insurers. The lack of reimbursement is especially pronounced in follow-up scans; it is more difficult to obtain reimbursement for follow-up studies for therapeutic monitoring especially for Medicare patients.

Although a number of studies demonstrate the utility of PET/CT for staging and monitoring cervical cancers, more research is needed. We need to better understand the role and frequency of follow-up studies as well as treatment planning imaging.