Newswise — Radiation therapy for head and neck cancer is a well accepted treatment and valuable adjunct in regional control when used in conjunction with surgery. It has also been shown to be an effective alternative to surgery when functional preservation is of utmost importance. However, as with many good treatment modalities, there are short and long term morbidities and occasionally mortalities. One unforeseen consequence could be radiation induced malignancy, which has been examined in a new research study.
The authors of "Radiation Induced Malignancy of the Head and Neck," are Keith Sale MD, Douglas Girod MD, Derrick Wallace MD, and Terence Tsue, MD FACS, all from the University of Kansas Medical Center, Kansas City, KS. Their findings will be presented at the American Academy of Otolaryngology-Head and Neck Surgery Foundation http://www.entnet.org Annual Meeting and OTO EXPO, being held September 21-24, 2003, at the Orange County Convention Center, Orlando, FL.
Methodology: A retrospective review of patient charts from 1985 to the present was performed to identify patients with radiation induced malignancies (RIMs). Patient information was gathered from the Kansas Tumor Registry, from outpatient and hospital clinic charts, and from pathology records. Patients were included in this study based on criteria of (1) the tumor arose in a previously irradiated field; (2) the new tumor is histologically different from the original condition; (3) there was no evidence of the new tumor at the time of radiation therapy.; (4) a latency period existed between irradiation and the development of the new tumor.
Because of the extensive literature available that links radiation therapy to skin and thyroid cancers, patients with these types of RIMs were excluded. Data collected included patient demographics, primary diagnosis leading to radiation therapy, radiation induced tumor type, tumor location, and treatment.
Results: Thirteen patients (seven male, six female) met the criteria. Patient ages ranged from 13-78 years. Eight patients were irradiated for prior malignancies and five patients were treated for benign conditions. Radiation induced malignancies were most commonly sarcomas (eight), but also included squamous cell carcinoma (two) adenoid cystic carcinoma (two), and acinic cell carcinoma (one). RIMs occurred most frequently in the paranasal sinuses, but were also found in the pharynx, mandible, neck soft tissues, and salivary glands. The latency period ranged from nine months to 49 years. The average latency period in this series was 17 years. The dosage of radiation given was documented in only two cases.
The treatment of choice was wide local resection. Follow up ranged from one to four years. Eight patients are currently alive without disease, four patients are alive with disease, one patient has died from his disease, and one patient has been lost to follow up. The incidence of RIMs in relation to new head and neck cancers at the University of Kansas Medical Center was one percent.
Conclusions: The findings from this study have led the researchers to suggest new definitive criteria for RIM of the head and neck generated from radiation induced sarcomas. They propose the criteria for identification of such patients be the selection guidelines for subjects in this study.
In this study, sarcomas were the most common type of RIM and the paranasal sinuses were most common location. Neither of the previous studies noted patient history regarding tobacco or alcohol use. This leaves open the possibility that other carcinogenic substances may have contributed to the large number of SCCA seen in those studies. In our study neither of the patients who developed radiation induced SCCA used tobacco or alcohol making the diagnosis of RIM that much more plausible. The authors conclude that radiation induced malignancy of the head and neck is a rare but life threatening complication of radiation therapy. Locoregional control of RIM can be very difficult and the treatment of choice remains wide local excision. Because the latency period for RIM is so variable, lifelong follow up should be the standard of care for any patient who has been treated with radiation therapy.
RSS