Osteoradionecrosis risk higher than thought.
Moreover, intensity-modulated radiation therapy (IMRT) was not associated with significantly lower rates of jaw complications, compared with older radiation techniques, although there was a slight trend in that direction and the interval to developing jaw complications was longer following IMRT, reported Dr. Beth M. Beadle at the symposium.
In the literature, osteoradionecrosis (ORN), the most severe jaw manifestation resulting from head/neck radiation, was reported on average in 11.8% of patients in 10 studies (total, 3,312 irradiated patients) from the 1930s through the 1960s, said Dr. Beadle, a radiation oncologist at the University of Texas M.D. Anderson Cancer Center, Houston.
With improved technologies, the rate dropped to 5.4%, as documented in 21 studies involving a total of 11,077 patients conducted from the 1970s through the early 1990s. Since 1997, 25 retrospective and prospective studies involving 9,632 patients overall have reported an overall average ORN rate of 3.0%, she said.
For the current study, data were taken from the SEER (Surveillance, Epidemiology and End Results) database for Medicare beneficiaries. Patients who were diagnosed with oral cancers in 1999-2007 were identified using SEER, ICD-9, and CPT codes. Primary tumor sites included those of the lip, tongue, floor of mouth, gum, tonsil, oropharynx, and other oral cavity and pharynx.
Of 1,848 patients overall, 16.1% (297) had at least one osteoradionecrosis code within 90 days of radiation therapy completion. Of those, 256 patients had ICD-9 diagnostic codes that included those for osteonecrosis of jaw (733.45), osteomyelitis of jaw (526.4), and other diseases of the jaws, including inflammatory conditions, alveolitis, and periradicular pathology (all 526.x).
Some 41 patients (3.8% of the total) had CPT procedure codes, including drainage of abscess (41800), alveolecto-my (41830), operations on facial bones or joints with concurrent ORN diagnosis (76.3), or hyperbaric oxygen therapy (99183), and 30 patients (1.6% of the total) had both a diagnostic and a procedural ORN code, Dr. Beadle said.
The percentage of patients who required intervention for ORN (3.8%) is more consistent with the overall ORN rates from the literature, suggesting that most previous studies have captured only the more severe osteoradionecrosis, which is usually defined as that requiring a procedure, she explained.
In univariate analysis, female sex, not receiving chemotherapy, and a lower number of comorbidities on the Charl-son Comorbidity Index were the only factors significantly associated with all jaw complications.
Receipt of IMRT was not a significant predictor, although there was a trend. Patients who received IMRT differed significantly from non-IMRT patients in several ways, however, including their younger age and their greater likelihood to be male, to have advanced-stage disease, to have received definitive vs. adjuvant treatment, to have received chemotherapy, and to have fewer comorbidities.
Although IMRT per se did not predict jaw complications, there was a longer time interval between treatment and the development of jaw complications among the patients who received IMRT (462 days vs. 386 days for the non-IMRT patients).
In response to questions from the audience, Dr. Beadle said that it wasn't clear why jaw complications would be more common among patients who did not receive chemotherapy, but it might be that those patients received higher doses of radiation. As for the sex difference, she suggested it may be that women have better follow-up care, or it might relate to either osteoporosis or use of bisphosphonates. Her group is investigating those possibilities.
Dr. Beadle stated that she has no disclosures.
RELATED ARTICLE: VITALS
Major Finding: Of a total 1,848 patients with oral cancers, 16% (297) had at least one osteoradionecrosis code within 90 days of radiation therapy completion.
Data Source: Data were taken from the SEER database for Medicare beneficiaries.
Disclosures: Dr. Beadle reported having no financial disclosures.
BY MIRIAM E. TUCKER
FROM A HEAD AND NECK CANCER
SYMPOSIUM SPONSORED BY THE AMERICAN SOCIETY FOR RADIATION ONCOLOGY
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|Author:||Tucker, Miriam E.|
|Publication:||Internal Medicine News|
|Article Type:||Clinical report|
|Date:||Mar 15, 2012|
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