Abstract
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Objectives We investigated the clinical significance of FDG-avid lymphadenopathy in the ipsilateral inguino-femoral area in patients with lower extremity osteosarcoma treated with surgical resection and endoprosthetic replacement.
Methods Among patients with lower extremity osteosarcoma treated with surgical resection and endoprosthetic replacement between 2007 to 2011, we retrospectively enrolled patients who underwent whole body FDG PET/CT before and after surgery. A case with newly detected inguino-femoral lymph nodes showing higher FDG uptake than surrounding normal tissue were defined as LN (+) on each PET/CT data set. Cases with LN (+) were clinically followed up at least for 12 months after the development of LN (+).
Results A total of 91 patients (M:F = 67 : 24, Age: 15±11) were enrolled. Twenty-eight (30.8 %) of these patients showed LN (+) PET/CT scan before (n = 18) or after surgery (n = 10). Among 18 patients who showed LN (+) before surgery, 12 patients showed LN (+) before neoadjuvant chemotherapy, and 6 patients during or after neoadjuvant chemotherapy. Among 10 patients who showed LN (+) after surgery, 5 patients showed LN (+) within 6 months after surgery and 5 patients between 6 months and 1 year. During clinical follow up (median, 63 months; range, 12 - 91 months), all the cases with LN (+) were proven to be benign lymphadenopathies. Age, sex, or primary tumor site were not correlated with existence of FDG-avid lymphadenopathy. There were no significant differences of metastasis-free survival between LN (+) group and LN (-) group.
Conclusions FDG-avid inguino-femoral lymphadenopathy is frequently encountered on the pre- or postoperative FDG PET/CT of lower extremity osteosarcoma. However, none of these inguino-femoral lymphadenopathies was proven to be true metastasis, and existence of FDG-avid lymphadenopathy was not related with prognosis.