CORR Insights®: Regional Lymph Node Involvement Is Associated with Poorer Survivorship in Patients with Chondrosarcoma: a SEER Analysis.

Abstract

Generally speaking, lymph node involvement is only considered to occur in certain histologic sarcoma subtypes, such as rhabdomyosarcoma, angiosarcoma, clear cell sarcoma, epithelioid sarcoma, and synovial sarcoma [1, 6, 7, 10, 11]. However, according to some investigations, synovial sarcoma nodal metastases are quite rare, and myxoid liposarcoma may be more deserving of being on that list [5]. In the current study, Wan and colleagues [13] use a large database to evaluate a rare disease, and they learned that the prevalence of lymph node involvement across all chondrosarcoma subtypes (excluding the misnomer extraskeletal myxoid chondrosarcoma) was 1.3%. While an admittedly small prevalence, this number is perhaps larger than one would expect as reports of nodal metastases from bone sarcoma are extremely rare [3, 4, 12]. The current study discusses nodal involvement at the time of initial staging. The authors designed the study this way because the SEER database does not support longitudinal evaluation of these parameters. Therefore, the prevalence of node involvement discussed is really the prevalence at the time of the initial diagnosis and not the likelihood of developing nodal metastatic disease over the course of treating chondrosarcoma. That being so, in a study like this, there is no way to confirm the accuracy of true nodal disease (metastatic spread to the lymph nodes) as compared to direct extension into the lymphatic system (tumor invasion into the lymph nodes). Similarly, there is no way to confirm whether the physician who entered the data for each patient carefully considered the nodal evaluation in their reporting of the stage. This may be important, because surgeons may not have paid careful attention to the lymphnode status of tumors that aren’t supposed to spread by way of the lymphatic system. Unfortunately, most of what we know about this topic comes from case reports [3, 8, 9]. Nevertheless, the authors nicely demonstrate here that lymph node involvement is an independent risk factor for having a poor oncologic outcome. Given that the overall survival was nearly 50% less for patients with lymph node involvement, it should be considered another surrogate marker of biologic activity of the tumor (similar grade and metastatic status). Perhaps not surprisingly, lymph node involvement was demonstrated to be more likely in patients with larger, higher-grade tumors. However, we learn in the current study that there is a threefold increase of lymph node metastases if the primary tumor originates in an extraskeletal location [13], a finding we’ve also seen in patients with osteosarcoma [12].