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!
Multi-year study finds 'hotspots' of ammonia over world's major agricultural areas
17.03.2017 | University of Maryland
Diabetes Drug May Improve Bone Fat-induced Defects of Fracture Healing
17.03.2017 | Deutsches Institut für Ernährungsforschung Potsdam-Rehbrücke
Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.
The results will be published on March 22 in the journal „Astronomy & Astrophysics“.
Galaxy clusters are the largest gravitationally bound structures in the universe. With a typical extent of about 10 million light years, i.e. 100 times the...
Researchers at the Goethe University Frankfurt, together with partners from the University of Tübingen in Germany and Queen Mary University as well as Francis Crick Institute from London (UK) have developed a novel technology to decipher the secret ubiquitin code.
Ubiquitin is a small protein that can be linked to other cellular proteins, thereby controlling and modulating their functions. The attachment occurs in many...
In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...
Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are less stable. Now researchers at the Technical University of Munich (TUM) have, for the first time ever, produced a composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process. This brings the scientists a significant step closer to industrial applications like flexible displays and photosensors.
Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are...
Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to simulate these confined natural conditions in artificial vesicles for the first time. As reported in the academic journal Small, the results are offering better insight into the development of nanoreactors and artificial organelles.
Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to...
20.03.2017 | Event News
14.03.2017 | Event News
07.03.2017 | Event News
23.03.2017 | Life Sciences
23.03.2017 | Power and Electrical Engineering
23.03.2017 | Earth Sciences