Osteonecrosis of the jaw: Long-term follow-up shows variable rate of healing

Background: Osteonecrosis of the jaw (ONJ) is a rare but clinically significant disorder recently reviewed in a large retrospective study (Hoff et al, 42nd ASCO Annual Meeting 2006, Abstract #8528). A subset of the ONJ patients from that study with breast cancer or multiple myeloma (MM) was followed at the University of Texas M.D. Anderson Cancer Center (UTMDACC) dental clinic. This analysis describes the natural history of ONJ in this subset. Methods: Thirteen of 29 ONJ patients treated with intravenous bisphosphonates (IVBP) at UTMDACC and 1 treated elsewhere were evaluated in the dental clinic for > 6 months (MM, n=7; breast cancer, n=7). The maximum length of exposed bone was measured at each visit. Patients received a standard regimen of conservative dental care with debridement when indicated. Results: All 14 patients received zoledronic acid (median cumulative dose 72 mg; range 24-152) and 10 also received pamidronate (median cumulative dose 1,710 mg; range 90-2,700). They were followed for a median duration of 17.1 months (range: 7.1-67.3). The mean length of exposed bone at initial evaluation was 11 mm (SD: 8.4). Each patient demonstrated fluctuating clinical courses. The lesion from baseline to the last visit progressed in 7 patients (median increase of 13 mm), remained stable in 2, regressed in 2 and resolved in 3. Persistent ONJ was seen if IVBP was stopped (n=8), decreased in frequency (n=1) or continued at the same dose/frequency (n=2). Complete resolution occurred in 3 MM patients, where IVBP was discontinued, decreased in frequency or replaced by weekly oral alendronate. Conclusions: Our experience shows that ONJ resolved in 21% but persisted in the majority of patients with a duration of up to 5 years with conservative dental care. Further studies are needed to evaluate the pathogenesis and healing process of ONJ.