Role of bone scan in routine practice for early recognition of bisphosphonate-related osteonecrosis of the jaws (ONJ): Pro and con.

Abstract

e20694 Background: The literature on the role of 99mTc-MDP bone scan (BS) in the diagnosis and follow-up of bisphosphonate-related ONJ is limited and unconsistent. Following data are in favour: a) BS is an imaging technique with high sensitivity; b) sporadic cases of early jawbone (maxilla or mandible) uptake have been reported, occasionally even months or years before the clinical evidence of ONJ (bone exposure); c) the jaw BS uptakes can change on different stages of ONJ disease (acute/symptomatic or less); d) the BS is performed periodically in patients with skeletal metastases to check out the status of disease activity and the response to specific treatments; consequently the research of ONJ does not involve additional costs. Vice versa, some limitations include: a) BS is a technique with low specificity; bone traumatic, inflammatory, degenerative lesions can determine an uptake; b) a non-negligible proportion of patients (even without any tumor disease) shows jaw uptakes, due to dental diseases widely seen in the general population (abscesses, denture ulcers,periodontal disease,etc.); c) even in BP-related ONJ suspected cases, jaw uptake may be due to infections that are not necessarily connected to the osteomyelitis component of ONJ; d) bone necrosis (sequestrum) is usually not uptaking at the BS, but it can appear as a downtaking area surrounded by an uptaking area. Methods: We conducted a retrospective study of 59 BS performed in 15 ONJ patients treated with BPs (8 with breast cancer,6 prostate cancer,1 renal cell carcinoma). Two Nuclear Medicine specialists reviewed 18 "baseline" BS (before treatment with BP), 14 BS in the 6-12 months prior to diagnosis of ONJ, 13 BS performed at the diagnosis time of ONJ (or within 6 months), 14 BS collected after the diagnosis of ONJ. Results: 6-12 months prior to diagnosis, 10 BS were positive (jaw uptakes in ONJ sites) and 4 negative. At the moment of ONJ diagnosis, 12 out of 13 exams resulted positive and one doubtful. Conclusions: These retrospective data will be used to design a case-control study with different patient groups, inluding ONJ cases, patients treated with BP and not suffering from ONJ, and cancer patients not receiving BPs.