The role of bone scintigraphy in the follow-up of osteogenic sarcoma.

The role of bone scintigraphy in the follow-up of osteosarcoma patients is still controversial. It is not yet clear whether bone scintigraphy results in early detection of relapse nor whether this can improve the survival rate of relapsed patients. In this study, results of scintigraphies obtained from 78 patients treated for osteosarcoma between 1978 and 1992 were analysed. 28/78 patients presented with 61 relapse sites, including 34 lung metastases, 20 distant relapses and 7 local recurrences. More than 90% of relapses were detected within 4 years after primary diagnosis of the tumour. A total of 489 bone scintigraphies were performed routinely during follow-up of these patients. 66/489 scintigraphies showed increased uptake of tracer. In 7/66 positive scintigraphies, a relapse was detected: lung metastases (3), local recurrence (1) and distant bone or soft tissue relapses (3). These relapses occurred between 1 and 4 years after primary diagnosis. In these cases, scintigraphies showed areas with increased uptake, although these patients had neither clinical symptoms nor positive X-rays or CT scans. At an observation period of 2.5 or 3.5 years, a second or third remission was induced in 2/6 patients in whom scintigraphy allowed an early diagnosis of the relapse. In conclusion, these data show that only a small number of routinely performed bone scintigraphies indicate a relapse. However, since bone scintigraphy is able to detect relapses early, the outcome of future relapsed patients might be improved. Therefore, bone scintigraphies should be included in a follow-up programme for patients with osteosarcoma. Since most relapses detected by scintigraphy occurred during the first 4 years after initial diagnosis, bone scintigraphy should be limited to this time frame.