Orthopaedic oncology; Early Lymph Node Metastasis May Predict Poor Prognosis in Soft Tissue Sarcoma
Soft-tissue sarcomas are a rare and heterogeneous group of tumors. The last few decades have seen rapid strides in surgery with function preserving alternatives for local control in these lesions becoming the norm without compromising on overall disease survival. Good functional and oncological results can be achieved with a combination of excision of the tumor, and where required, suitable adjuvant therapies. These lesions are best managed at specialty centres where the requisite multidisciplinary care can be offered to the patient to optimise results. This overview is intended as a review of current understanding and the multimodality management of these challenging tumors.
Distant metastasis is common in patients with soft tissue sarcoma (STS) of the extremities, occurring in about 25% of patients. Pulmonary metastasis is the most common form of metastatic disease. The median survival after a diagnosis of distant metastatic disease was approximately 12 months, with a 5-year survival of about 10%. However, several studies have suggested that surgical management of pulmonary metastasis has achieved 5-year survival rates of 30% or more.
Lymph node metastasis (LNM) is a relatively rare event in STS, except for lymphogenous histotypes such as rhabdomyosarcoma, epithelioid sarcoma, and clear cell sarcoma. The overall prevalence is 1.75–12% with an increasing frequency due to the implementation of FDG-PET for whole body screening. Regional LNM is an important prognostic factor in STS, suggesting that LNM represents a component of disseminated disease. Unlike pulmonary metastasis, the precise role of lymphadenectomy remains to be defined because LNM in patients with STS is rare, thereby limiting the feasibility of well-designed prospective studies to establish the role of lymphadenectomy. There are some reports describing an association between the time from the primary STS diagnosis to LNM and patient prognosis. However, the precise duration, from primary diagnosis to detection of LNM, affecting overall survival (OS) is unknown.
The objective of this study was to analyze the clinicopathological features and patterns of LNM, focusing on the time duration from the primary diagnosis to the detection of LNM.
The 5-year survival for patients with LNM from STS is reported to be 12.8% to 34.1%. In our study, the 5-year OS was 45.5%. The most common subtype of LNM was myxofibrosarcoma and undifferentiated pleomorphic sarcoma. The low prevalence of lymphogenous histotypes such as rhabdomyosarcoma, epithelioid sarcoma, and clear cell sarcoma may be a result of the small sample size of this study, resulting in relatively good OS. Although myxofibrosarcoma has a high rate of local recurrence, the overall risk of distant metastases is relatively low compared to that of other sarcoma subtypes; the 5-year local recurrence rate has been reported to be 18–31%, with corresponding OS rates of approximately 70%. The low risk of distant metastasis is a factor for the relatively good OS associated with myxofibrosarcoma.
Some reports describe that the survival of patients with LNM at diagnosis is similar to that of patients who later develop LNM . Therefore, we examined which time duration from primary diagnosis to detection of LNM influenced OS. Of the 33 patients with LNM, there were 19 patients with pulmonary metastases. All LNMs developed earlier than the pulmonary metastases, except for 1 patient.
In our study, it was demonstrated that any treatments for LNM did not result in a better survival than that of patients receiving no treatment. The potential benefit of lymphadenectomy remains to be defined. Lymphadenectomy has been shown to improve long-term survival, while radical lymphadenectomy does not confer a substantial survival benefit. This study suggests that early LNM (<8 months of duration from the primary tumor diagnosis) may have less impact to decide on an aggressive treatment for LNM.
We acknowledge several limitations of this study: First, there were a limited number of patients with LNM. Second, our study was limited by the fact that imaging assessment (CT or MRI) was used to examine the regional lesions at 3- to 6-month intervals. Therefore, we cannot detect all LNMs unless the patient presents with lymph node swelling. Third, we used a retrospective study design and not a single institutional study design. Fourth, several different histologic tumors were included. Fifth, treatment was not performed in a randomized, controlled fashion.
Coordinator| Journal of Orthopedic Oncology
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