Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Positron emission tomography superior to standard evaluation tools in measuring treatment response

04.02.2008
Standard evaluation imaging missed 80 percent of responders

Positron Emission Tomography (PET) was much more sensitive and more accurate than conventional imaging methods in detecting response to treatment in sarcoma patients, according to a UCLA study that is among the first to directly compare PET to CT scanning.

The study has important implications for patients. If conventional imaging fails to detect treatment response, oncologists may discontinue therapies that in fact are working and study participants may be dismissed from clinical trials that are actually helping them. Conversely, if a patient is not responding, using PET scanning to evaluate response could help prevent them from undergoing toxic therapies that aren’t working.

The study, conducted by a multidiscplinary team of scientists at UCLA’s Jonsson Cancer Center, appears in the Feb. 1, 2008 issue of Clinical Cancer Research. Researchers found that standard size-based evaluation methods only identified 20 percent of responders, while PET was able to identify responders 100 percent of the time.

Current practice evaluates response to treatment using RECIST, or Response Evaluation Criteria in Solid Tumors. Patients are scanned using CT or MRI before and after treatment and the scans are then compared to determine if the tumor has decreased in size. If there is no change, the disease is considered stable. A partial response is tumor shrinkage of more than 30 percent, while a total response is tumor elimination.

“We knew from our considerable experience with neoadjuvant therapy (treatment before surgery) in sarcoma patients, that measuring tumor size correlated poorly with response,” said Dr. Fritz Eilber, an assistant professor of surgery, director of the Sarcoma Program at UCLA’s Jonsson Cancer Center and senior author of the study. “We have removed many tumors that have not changed in size with treatment or have even grown, but are completely dead on pathologic analysis. Just because the tumor doesn’t shrink doesn’t mean the treatment didn’t work.”

Eilber and his team of top scientists, including PET scan inventor Michael Phelps, wanted to find a better way to predict response so patients would not have to undergo unnecessary treatment or be removed from therapies that were working. Since operable sarcomas are treated before surgery with chemotherapy and radiation, it was the ideal cancer in which to compare PET scanning to CT.

CT and MRI scans provide anatomical pictures of the body, while PET images many different biochemical functions in real time, acting as a sort of molecular camera. Unlike CT and MRI, PET doesn’t just take a snapshot of body structures, it watches what the body is doing.

In this study, researchers measured the metabolic activity of the tumor, or how much sugar was being consumed in the cancer cells. Cancer cells, because they’re growing uncontrollably, use much more sugar than do normal cells. Using a specific PET probe that measures sugar metabolism, researchers could determine whether the cancer cells in the tumor were still alive and dividing after chemotherapy and radiation, Eilber said.

Researchers used a PET/CT scanner in the study, a technologic advance that combines the imaging modalities in one machine. The combined scanner allowed researchers to directly compare the before and after treatment scans for both tumor size and metabolic activity.

“PET was much more sensitive in picking up response than size-based RECIST,” Eilber said. “RECIST missed a large percentage of patients that actually had a response. PET picked up all of the responders.”

The study also has important implications for long-term patient follow-up, Eilber said. PET scanning quickly tells doctors how much of the tumor is dead. The amount of tumor that dies during treatment correlates with patient outcomes. If a large amount of the tumor is killed during treatment, sarcoma patients experience increased survival and lower recurrence rates.

This form of monitoring response to treatment also will be important in evaluating patients whose cancers have spread throughout the body, Eilber said.

“Evaluating biologic responses to therapy is the future of cancer imaging,” he said.

Eilber and his team already are working to confirm their results in a larger study and are testing new metabolic tracers to assess treatment response.

The study represented a true multidisciplinary effort, Eilber said. Experts from surgery, medical oncology, radiology, pathology, orthopedics, nuclear medicine and biostatistics comprised the research team.

Kim Irwin | EurekAlert!
Further information:
http://www.mednet.ucla.edu

More articles from Studies and Analyses:

nachricht Win-win strategies for climate and food security
02.10.2017 | International Institute for Applied Systems Analysis (IIASA)

nachricht The personality factor: How to foster the sharing of research data
06.09.2017 | ZBW – Leibniz-Informationszentrum Wirtschaft

All articles from Studies and Analyses >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Neutron star merger directly observed for the first time

University of Maryland researchers contribute to historic detection of gravitational waves and light created by event

On August 17, 2017, at 12:41:04 UTC, scientists made the first direct observation of a merger between two neutron stars--the dense, collapsed cores that remain...

Im Focus: Breaking: the first light from two neutron stars merging

Seven new papers describe the first-ever detection of light from a gravitational wave source. The event, caused by two neutron stars colliding and merging together, was dubbed GW170817 because it sent ripples through space-time that reached Earth on 2017 August 17. Around the world, hundreds of excited astronomers mobilized quickly and were able to observe the event using numerous telescopes, providing a wealth of new data.

Previous detections of gravitational waves have all involved the merger of two black holes, a feat that won the 2017 Nobel Prize in Physics earlier this month....

Im Focus: Smart sensors for efficient processes

Material defects in end products can quickly result in failures in many areas of industry, and have a massive impact on the safe use of their products. This is why, in the field of quality assurance, intelligent, nondestructive sensor systems play a key role. They allow testing components and parts in a rapid and cost-efficient manner without destroying the actual product or changing its surface. Experts from the Fraunhofer IZFP in Saarbrücken will be presenting two exhibits at the Blechexpo in Stuttgart from 7–10 November 2017 that allow fast, reliable, and automated characterization of materials and detection of defects (Hall 5, Booth 5306).

When quality testing uses time-consuming destructive test methods, it can result in enormous costs due to damaging or destroying the products. And given that...

Im Focus: Cold molecules on collision course

Using a new cooling technique MPQ scientists succeed at observing collisions in a dense beam of cold and slow dipolar molecules.

How do chemical reactions proceed at extremely low temperatures? The answer requires the investigation of molecular samples that are cold, dense, and slow at...

Im Focus: Shrinking the proton again!

Scientists from the Max Planck Institute of Quantum Optics, using high precision laser spectroscopy of atomic hydrogen, confirm the surprisingly small value of the proton radius determined from muonic hydrogen.

It was one of the breakthroughs of the year 2010: Laser spectroscopy of muonic hydrogen resulted in a value for the proton charge radius that was significantly...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

ASEAN Member States discuss the future role of renewable energy

17.10.2017 | Event News

World Health Summit 2017: International experts set the course for the future of Global Health

10.10.2017 | Event News

Climate Engineering Conference 2017 Opens in Berlin

10.10.2017 | Event News

 
Latest News

Ocean atmosphere rife with microbes

17.10.2017 | Life Sciences

Neutrons observe vitamin B6-dependent enzyme activity useful for drug development

17.10.2017 | Life Sciences

NASA finds newly formed tropical storm lan over open waters

17.10.2017 | Earth Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>