© 2000 by Oxford University Press
Journal of the National Cancer Institute, Vol. 92, No. 1, 11-13,
January 5, 2000
© 2000 Oxford University Press
NEWS |
Head and Neck Cancers: Making Headway in Their Treatment?
The treatment of head and neck cancer is heading in new and more promising directions with shorter treatment times, the development of better radiosensitizers, and improvements in overcoming the often serious side effects of radiation.
These and other advances in treating head and neck cancers were presented at the recent American Society of Therapeutic Radiation Oncology meeting in San Antonio, Texas.
The idea behind shortening the time it takes to treat these cancers is that tumors will have less time to regrow. That means more aggressive radiation and telescoping the time between surgery and radiation treatment. It also can mean giving chemotherapy first to shrink the tumor, followed by a quick course of radiation.
This approach, however, may put a strain on the way things are done now at many medical centers where treatments are more drawn out, according to Kei-Kian Ang, M.D., professor of radiation oncology at the University of Texas M. D. Anderson Cancer Center, Houston. Shortening treatment time requires "a very tight collaboration between surgeons and radiation oncologists," Ang said, as well as a change in practice patterns.
In his prospective randomized study of 288 patients with advanced head and neck cancers, Ang found that those undergoing surgery and then treated with radiation for 5 weeks did better than patients similarly treated who underwent 7 weeks of radiation treatment.
"People should do everything possible to condense the treatment time," Ang urged. "And if they can't do that, then I think they should adopt a twice a day radiation treatment regimen, or perhaps add chemotherapy, although the value of chemotherapy is not proven yet."
Michael Hass, M.D., of the University of Maryland, however, disputed this view. He said that almost half of 60 head and neck cancer patients treated with adjuvant carboplatin and Taxol in his case series survived for 3 years — compared with a 20% to 30% survival for historical controls.
Meanwhile, recognition that small differences in the radiosensitivity of tumors can lead to big differences in outcomes, has led to a big scramble for better agents. Newer radiosensitizers include lipid modification enzymes such as farnesyltransferase inhibitors, which attack the H-ras allele present in some human cancers, and another that inhibits K-ras.
Another innovative approach is the use of antibodies to growth factors such as epidermal growth factor, which is commonly expressed but often overexpressed in head and neck carcinomas.
After a 100% response rate in an early pilot study, a multicenter trial is now under way using a monoclonal antibody (C225) to EGFR developed by Imclone Systems, New York, and radiation in one arm versus radiation alone in the other arm. At least two other drug companies are also studying EGFR blockade for head and neck cancers, hoping to follow the success of growth factor blockade for two other cancers.
James Bonner, M.D., chairman of radiation oncology at the University of Alabama, Birmingham, said that about 200 patients had been treated so far with the EGFR C225 antibody.
|
"The encouraging aspect of this upcoming trial," Bonner said, "is that it's based on the results we achieved in the UAB pilot study. To achieve a 100% response rate with advanced locally unresectable head and neck malignancies is really an important finding, so the Food and Drug Administration allowed us to go forward with a pivotal trial." He said the trial will involve 400 patients and be completed in about 2 years.
Karen Fu, M.D., professor of radiation oncology, University of California, San Francisco, reported results of a randomized Radiation Therapy Oncology Group study involving 1,000 patients. (See News, Dec. 15, 1999). She called the study a "major step forward" in showing that more aggressive radiation with accelerated fractionation can bring improved locoregional control over standard radiation therapy in head and neck cancers.
"And improved local control is intimately connected to quality of life," she added.
Giving patients amifostine about 15 minutes prior to their radiation treatments can also improve the quality of life, according to David Brizel, M.D., an associate professor of radiation oncology at Duke University Medical Center, Chapel Hill, N.C. Doing so, he said, reduced the incidence of dry mouth — a major side effect of radiation therapy — to 51% from 78%. The randomized study involved more than 300 patients with newly diagnosed head and neck cancer.
Ultimately, while many of these new treatments hold promise, they alone are not going to solve the problem of head and neck cancers: regional recurrences and second primaries. Studies of retinoids at M. D. Anderson have indicated that these vitamin A derivatives may delay the appearance of new tumors in the aerodigestive tract, rather than prevent them entirely, according to Waun Ki Hong, M.D., who delivered a keynote address on chemoprevention.
|
A large ongoing study there involves determining response profiles, so that hopefully preventive therapy can be tailored to individuals, he said.
CiteULike 
Connotea 
Del.icio.us What's this?
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||