Purpose of the report: identifying imaging predictors of healing of osteonecrosis of the jaw (ONJ) in cancer patients may assist in better stratification of treatment strategies.
Materials and methods: patients with ONJ were followed prospectively and underwent bone scintigraphy, both planar and single-photon emission computed tomography (SPECT) imaging. End points were time to healing and the number of recurrences. Studied parameters included lesion visibility, pattern of uptake, and quantification of uptake relative to the unaffected side.
Results: a total of 22 patients were recruited (3 men; 19 women) with a stage 1 ONJ lesion in 8, stage 2 in 9, and stage 3 ONJ in 5 patients. Median duration of follow-up was 12 months (range, 6-37). SPECT acquisitions proved superior over planar images in detecting ONJ lesions (P = 0.03). Quantification of tracer uptake in the ONJ lesion relative to the unaffected side showed increasing uptake with higher stages of ONJ: mean, 1.67 (95% confidence interval [CI], 1.17-2.18) in stage 1, 2.72 (95% CI, 2.24-3.20) in stage 2, and 4.62 (95% CI, 3.98-5.26) in stage 3. In addition, this relative ratio of uptake was found to be an independent predictor of ONJ healing (hazard ratio, 0.24; 95% CI, 0.07-0.82; P = 0.02). Neither ONJ stage nor relative ratio of uptake were predictors of the occurrence of ONJ relapses.
Conclusions: bone scintigraphy in patients with ONJ is feasible and SPECT acquisitions are preferred over planar images. Relative quantification of tracer uptake provides prognostic information independent of clinical stage that may assist in identifying patients with a poor prognosis.