Patients with cancers of the head and neck who received intensity-modulated radiation therapy (IMRT) - a technology designed to more precisely target cancer cells and spare nearby tissue - experienced improved outcomes, as well as reduced toxicities, compared to patients receiving conventional radiation therapy, according to new research from The University of Texas MD Anderson Cancer Center.
The study, published in the journal Cancer, is the first to document this finding in a large population-based group, as well as the first to suggest IMRT could improve outcomes in head and neck cancer patients.
"Previous studies indicated that patients treated with IMRT did better when it came to treatment-related side effects, however these studies were not designed to examine survival," said Beth Beadle, M.D., Ph.D., assistant professor in MD Anderson's Radiation Oncology. "The survival data was not well-known because IMRT is intended to spare normal tissues but still deliver radiation to the tumor so previous models assumed it was equivalent survival at best."
IMRT employs multiple beams of radiation that allows oncologists to provide a dosage that conforms to the tumor, often at varying intensities, while limiting exposure to surrounding tissue.
Since being approved in 1999 for the treatment of head and neck cancer, IMRT use has substantially increased due to its advantages in being able to target complicated tumors while minimizing patient side effects such as xerostomia (chronic dry mouth), dental complications, fibrosis and range of motion impairments.
Researchers on the population-based retrospective study used the Surveillance, Epidemiology and End Results (SEER) Medicare database, compiled by the National Cancer Institute, to identify 3,172 patients treated for head and neck cancer between 1999—2007 who received either conventional radiation therapy or IMRT.
In total, 1,056 patients were treated with IMRT and 2,116 were treated with conventional therapy. All head and neck cancer subtypes were included, with the most common, squamous cell carcinoma, accounting for 91.2 percent. The primary outcome was cause-specific survival (CSS), which reflects the chances of dying from head and neck cancer after 40 months of follow-up.
To account for differences in the patient population with those being treated with IMRT possibly representing a different cohort due to the evolution of treatments, researchers used propensity scoring to create a matched comparison. This scoring model takes into account age at diagnosis, gender, race/ethnicity, income and education, among other factors.
Results Show Outcomes Improved
Beadle and colleagues found that patients treated with IMRT had a statistically significant improvement in CSS compared to those treated with conventional therapy, 38.9 percent vs. 18.9 percent, respectively.
Although propensity scoring matched patients for known variables, the researchers noted there was still a possibility for bias in the two treatment groups as a result of unmeasured variables. To account for this, an instrumental variable model was used that also demonstrated IMRT increased survival.
"From a scientific perspective, the findings support the use of IMRT and suggests we can provide excellent care while optimizing cancer outcomes and reducing toxicities," Beadle said. "At a more global level, with concerns about health care financing and resource allocation, IMRT is more expensive than conventional radiation therapy, but the data suggest it's worth it."
The authors note a separate and recent study (Yong et al.) that examined the cost effectiveness of IMRT in the treatment of oropharynx cancer found reason to support its use. Despite increased upfront costs, the study found IMRT could avoid a case of xerostomia with an incremental cost of $4,532.
Beadle said additional work is required to more closely examine the cost-effectiveness of IMRT. However, she noted that if the therapy can reduce or eliminate subsequent disease recurrences, or treatment-related side effects, the cost impact could be favorable.
With observational studies, the authors said limitations do exist including the uncertainty of Medicare claims data and the absence of data for younger patients. Additionally, the authors note there was an absence of human papillomavirus (HPV) status, which may affect tumor control.
None of the authors have conflicts to declare.
In addition to Beadle, other authors on the all-MD Anderson study include: Thomas Buchholz, M.D., division head Department of Radiation Oncology, B. Ashleigh Guadagnolo, M.D., associate professor, Department of Radiation Oncology, Adam Garden, M.D., professor, Department of Radiation Oncology, K. Kian Ang, M.D., Ph.D., professor, Department of Radiation Oncology, Linda Elting, Dr.P.H., professor and Kai-Ping Liao, Ph.D., both of the Department of Health Services Research.
Will Fitzgerald | EurekAlert!
Drone vs. truck deliveries: Which create less carbon pollution?
31.05.2017 | University of Washington
New study: How does Europe become a leading player for software and IT services?
03.04.2017 | Fraunhofer-Institut für System- und Innovationsforschung (ISI)
An international team of scientists has proposed a new multi-disciplinary approach in which an array of new technologies will allow us to map biodiversity and the risks that wildlife is facing at the scale of whole landscapes. The findings are published in Nature Ecology and Evolution. This international research is led by the Kunming Institute of Zoology from China, University of East Anglia, University of Leicester and the Leibniz Institute for Zoo and Wildlife Research.
Using a combination of satellite and ground data, the team proposes that it is now possible to map biodiversity with an accuracy that has not been previously...
Heatwaves in the Arctic, longer periods of vegetation in Europe, severe floods in West Africa – starting in 2021, scientists want to explore the emissions of the greenhouse gas methane with the German-French satellite MERLIN. This is made possible by a new robust laser system of the Fraunhofer Institute for Laser Technology ILT in Aachen, which achieves unprecedented measurement accuracy.
Methane is primarily the result of the decomposition of organic matter. The gas has a 25 times greater warming potential than carbon dioxide, but is not as...
Hydrogen is regarded as the energy source of the future: It is produced with solar power and can be used to generate heat and electricity in fuel cells. Empa researchers have now succeeded in decoding the movement of hydrogen ions in crystals – a key step towards more efficient energy conversion in the hydrogen industry of tomorrow.
As charge carriers, electrons and ions play the leading role in electrochemical energy storage devices and converters such as batteries and fuel cells. Proton...
Scientists from the Excellence Cluster Universe at the Ludwig-Maximilians-Universität Munich have establised "Cosmowebportal", a unique data centre for cosmological simulations located at the Leibniz Supercomputing Centre (LRZ) of the Bavarian Academy of Sciences. The complete results of a series of large hydrodynamical cosmological simulations are available, with data volumes typically exceeding several hundred terabytes. Scientists worldwide can interactively explore these complex simulations via a web interface and directly access the results.
With current telescopes, scientists can observe our Universe’s galaxies and galaxy clusters and their distribution along an invisible cosmic web. From the...
Temperature measurements possible even on the smallest scale / Molecular ruby for use in material sciences, biology, and medicine
Chemists at Johannes Gutenberg University Mainz (JGU) in cooperation with researchers of the German Federal Institute for Materials Research and Testing (BAM)...
19.06.2017 | Event News
13.06.2017 | Event News
13.06.2017 | Event News
26.06.2017 | Life Sciences
26.06.2017 | Physics and Astronomy
26.06.2017 | Information Technology