Technetium-99m-MDP scintigraphy and long-term follow-up of treated primary malignant bone tumors

Local malignant bone tumor excision followed by high-dose extracorporeal irradiation (300 Gy) and subsequent reimplantation is a unique technique for treatment of primary bone and cartilage tumors. The long-term scintigraphic findings of irradiated bone autografts in relation to clinical patient data were reviewed retrospectively.

Thirty-seven patients (12 women, 25 men; age range 13.0-66.7 yr; average age 29.1 yr) were studied. Postsurgical anatomopathological diagnoses included osteosarcoma, 20 patients; chondrosarcoma, 7 patients; and other less-frequent primary osteogenic tumors, 10 patients. Three hundred ninety 99mTc-methylene diphosphonate (MDP) whole-body scans performed between 3 mo and 18.3 yr (mean 6.5 yr) after treatment were reviewed.

The 10-yr actuarial survival rate was 78%. After a mean period of 19.4 mo, 6 patients developed a local recurrence, and MDP scintigraphy detected the recurrence in 4. Distant metastases developed in 11 patients (30%), of which 10 were nonosseous. Initially, all autografts appeared as photon-deficient areas. Diffusely increased bone uptake was present at osteotomy sites and at articulating surfaces contiguous with autografts within the first few months after surgery. Of all 25 patients with adequate follow-up, 7 showed persistent decreased uptake up to 129 mo after surgery. The other patients developed partial tracer uptake after 19.6 mo, on average. In 6 patients, scintigraphic images consistent with complete revascularisation were noted later (mean 31.5 mo). Local, sometimes multiple, complications were noted in 22 patients, mainly mechanical graft-related (15) or infections (11). Scintigraphic sensitivity for mechanical complications was 100%. Significantly more fractures and collapses were seen when partial tracer uptake suggestive of revascularisation occurred. Altered bone stress gave rise to focal and diffuse scintigraphic abnormalities, often in the spine and lower extremities. In recent literature, similar clinical complication patterns are found for massive allografts.

Skeletal scintigraphy is a sensitive technique for evaluating long-term follow-up of massive grafts to treat primary malignant bone tumors. Revascularisation and partial bone ingrowth are not sufficient conditions for a lower complication rate.