Pelvic chondrosarcomas: surgical treatment options.

INTRODUCTION: Chondrosarcoma (CS) is a primary malignant bone tumor with cartilaginous differentiation. The only available treatment is carcinological surgical resection since the usual adjuvant treatments are ineffective. The pelvic location creates specific technical difficulties both for exeresis and reconstruction. Our objective was to evaluate the carcinological and functional outcomes of inter-ilioabdominal amputation and conservative surgery.

MATERIALS AND METHODS: We retrospectively studied 59 cases of pelvis chondrosarcoma managed in our department between 1968 and 2003. Demographic, anatomopathological, surgical and survival data were analyzed. Survival was estimated by the Kaplan-Meier curves and the cumulative incidence method. Multivariate analysis was used to identify all possible independent prognostic variables.

RESULTS: There were 33 men and 26 women, with an average age of 48 years. The average follow-up duration was 94 months. Eleven patients had a grade 1 chondrosarcoma, 36 a grade 2 chondrosarcoma, five were grade 3, and seven were dedifferentiated chondrosarcoma. Eleven patients underwent an inter-ilioabdominal disarticulation, and 48 had a more conservative surgery. Resection margins proved healthy in 46 patients (78%). Eighteen patients (31%) had a local recurrence, and 12 (20%) had metastases. At last follow-up, 30 patients (51%) were still alive without any sign of recurrence. Twenty-three patients (39%) died from the disease. Multivariate analysis showed that margin invasion was associated with a definitely increased local recurrence rate. A high tumoral grade was correlated with a greater risk of metastases occurrence. These two last factors (margin status and tumor grade) as well as acetabulum involvement were correlated with a reduced survival rate. Function was better among patients treated by conservative surgery, and among them, even better when the peri-acetabular area remained intact. Our study confirmed that resection margins quality is a major prognostic factor both for local control and for survival. On the other hand, local recurrence is an adverse survival prognosis factor and is itself correlated with resection margins quality. Peri-acetabular chondrosarcoma location (in zone 2) appears to be a poor oncological prognosis factor since, in this location, obtaining healthy margins appears particularly difficult. Compared to resection, inter-ilioabdominal amputation did not prove its superiority concerning resection margins quality or survival. However, resection guaranteed a better functional outcome.

CONCLUSION: Chondrosarcoma of the pelvic girdle remains of worse prognosis than peripheral bones chondrosarcoma since the critical prognosis factor is the resection margins quality. This location, and especially the peri-acetabular zone, poses difficult specific technical problems when conservative surgery is selected. Various imaging techniques should help better envision tumor resection extent. Inter-ilioabdominal amputation should only be resorted to in non-metastatic patients, when the tumor does not seem to be removable with sufficient healthy margins guarantee, or when local conditions make it impossible to hope for a good quality reconstruction.

LEVEL OF EVIDENCE: Level IV; therapeutic retrospective study.