Clinical Epidemiology of Low-Grade and Dedifferentiated Osteosarcoma in Norway during 1975 and 2009

Table 4

Summary of treatment in 54 patients with low-grade or dedifferentiated osteosarcoma (OS).

	Low-grade OS (%)	Dedifferentiated OS (%)	All patients (%)
Surgery	42	12	54
Amputation	3 (7)	2 (17)	5 (9)
Other	39 (93)	10 (83)	49 (91)
Surgical margins	40	12	52
Free margin	35 (87)	8 (67)	43 (83)
Positive margin	5 (13)	4 (33)	9 (17)
Chemotherapy	3	8	11
Adequate chemotherapy	2 (67)	7 (88)	9 (82)
At primary diagnosis	1 (33)	5 (63)	6 (55)
Treatment of local relapse	1 (33)	2 (25)	3 (27)
Not adequate chemotherapy	1 (33)	1 (13)	2 (18)
Radiotherapy	5	5	10
Curative treatment intention	4 (80)	2 (40)	6 (60)
Palliative treatment intention	1 (20)	3 (60)	4 (40)

Surgical margins after last resection of primary tumour during primary treatment or later relapses. Two uncertain cases were not included. Radiotherapy during primary treatment or later relapses. One patient that underwent radiotherapy with curative intent received later radiotherapy in a palliative setting. The chemotherapy was terminated after an internal hemipelvectomy, since the operation specimen verified a LGOS. The patient was subsequently followed for ten years after primary surgery with no signs of recurrent disease.