Bone metastasis can be noted in the course of many primary malignant neoplastic lesions; breast and prostate cancers are the most frequent, but lung, kidney, and thyroid malignancies frequently metastasize to bones. Secondary osseous lymphomatous infiltrations is relatively uncommon and mainly noted in patients with non-Hodgkin lymphoma (NHL). By adding the metabolic changes to the conventional CT morphologic changes, combined positron emission tomography (PET) and computed tomography (CT) may offer clinically useful addition in assessment of treatment response of these lesions and offer helpful judgment for the different oncologic therapeutic regimens.
The study included 45 patients, 24 females (53.33%) and 21 males (46.66%). Showing bone dominant or isolated bony secondary malignant infiltrations. The study included 24 patients with history of breast cancer (53.33%), 12 patients with history of lymphoma (26.66%), and 9 patients (20%) with history of lung cancer. All the bony lesions included in the study were multiple lesions in each patient, classified into mixed lytic and sclerotic bony lesions in 21 patients (46.66%), sclerotic lesions in 12 patients (26.66%), and radiologically occult lesions or osteopenic areas in 12 patients (26.66%). The most accurate SUV max cut-off value among studied cases was 4, taking the lesion with highest SUV max value as the reference standard, with measurements taken before and after the medical regimen with six months interval. Confirmation of PET/CT results was done by serial post management follow up at 6 months interval and 1 year interval.
PET/CT study is an effective tool for assessment of treatment response for ossoues secondary malignant lesions.