Daily Bulletin 2015

Imaging Takes on Predictive Role in Gynecological Cancer

Wednesday, Dec. 02, 2015

When it comes to gynecological cancers, imaging is transitioning from a position in which it is descriptive and morphologic, to one in which it is predictive and molecular.

Yanchun Wang

Yanchun Wang

Susanna Lee, M.D., Ph.D.

Susanna Lee, M.D., Ph.D.

Jung Jae Park, M.D.

Jung Jae Park, M.D.

That was the message during a Tuesday session on imaging gynecological malignancies. "Imaging is going to be a predictive test," said Susanna Lee, M.D., Ph.D., chief of Women's Imaging at Massachusetts General Hospital and the session's keynote speaker. "It's going to tell us how the therapy is going to work, how the patient is going to do during therapy over the long term, and what that patient's survival chances are going to be."

"It's really a biomarker, which is a really important role that imaging has taken in cancer therapy," she added.

Gynecologic imaging is also becoming more molecular, she said. "We're going to go from morphologic imaging of the organ to micro-environmental imaging of the tissue describing the metabolism of the cell, and finally down to the molecules of the genomes."

"We need to do this because the therapy people have preceded us into the molecular world," she said "The current chemotherapeutic agents are targeted to specific molecules in specific cellular pathways and we need to be able to image this in order to help them treat their patients."

DWI has Potential as Novel Imaging Biomarker

In one such session, Jung Jae Park, M.D., Samsung Medical Center, Sungkyunkwan University School of Medicine in Seoul, Republic of Korea, described a study in which he and his colleagues compared the prognostic value of diffusion weighted MRI (DWI) and PET/CT during concurrent chemotherapy (CCRT) of cervical cancer for predicting disease progression.

Among its advantages, DWI is fast and non-invasive and imaging findings can be quantified using the apparent diffusion coefficient (ADC). Thus, the potential of DWI as a novel imaging biomarker reflecting tumor aggressiveness has grown markedly.

And while PET-CT is certainly a key imaging technique, it does involve extensive pre-imaging preparation and exposes patients to ionizing radiation, he said. "Therefore, we wanted to compare the predictive value of an imaging marker derived from DWI (ADC value) and PET-CT (SUV value) to determine that these imaging techniques could be potentially interchangeable for predicting patients' outcomes."

Dr. Park and his colleagues studied 67 patients who underwent CCRT for locally advanced cervical cancer and underwent both diffusion-weighted MRI and PET/CT before and during treatment.

They found that the degree of change in the ADC value of cervical cancer during one month of CCRT had a predictive value for estimating patients' prognosis after treatment, and that the degree of change in tumor ADC (mean ADC) and SUV (maximum SUV) were correlated.

"The most important and original finding of this study was that the degrees of change in tumor ADC and SUV are similar," Dr. Park said. "And they revealed similar prognostic performance for predicting patient prognosis regarding disease progression after CCRT of cervical cancer."

Dr. Park said that the findings suggest that these imaging biomarkers are feasible for developing predictive models for estimating treatment outcome.

In another presentation Yanchun Wang, of the Department of Radiology, Tongji Hospital, Wuhan, China, discussed her study showing that intravoxel incoherent motion (IVIM) diffusion weighted MRI could help predict and monitor the effectiveness of neoadjuvant chemotherapy (NACT) for cervical cancer.

Wang and her colleague at Tongji Hospital, Dao Y. Hu, M.D., Ph.D., recruited 42 patients with primary cervical cancer. IVIM diffusion weighted MRI was performed at three points during the administration of NACT—prior to NACT, three weeks after the first administration of NACT and three weeks after the second administration of NACT.

Treatment response was assessed according to RECIST criteria three weeks after the second administration of NACT and the patients were then divided into responders and non-responders.

Before treatment the diffusion coefficient (D) and standard ADC values were significantly higher in responders than non-responders. A receiver operating characteristic curve analysis yielded area under curve values of 0.804 and 0.678 respectively and, according to Wang, could be used to differentiate responders from non-responders.

D and Standard ADC values in responders remained significantly higher than non-responders three weeks after both the first and second NACT treatments.

"IVIM may be useful for predicting and monitoring the efficacy of NACT in cervical cancer," Wang concluded. "And D and ADC values could represent reliable early predictors of NACT response."

Question of the Day:

I am treating a patient for thyroid cancer with Iodine 131. He makes pasta for a living and wants to know when he can go back to work.

Tip of the day:

Tendons and ligaments may experience "magic angle artifacts" caused by very short T2 times when the tightly bound collagen is at ~55 degrees from the main magnetic field.

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