Regional and in-transit lymph nodes for extremity tumors

Because of the significant incidence of regional nodal spread in patients with extremity primary tumors (often without clinical evidence of involvement) and because of the prognostic and therapeutic implications of nodal involvement, extensive pretreatment assessment of regional and in-transit nodes is warranted.[90-94]; [95][Level of evidence C2] In-transit nodes are defined as epitrochlear and brachial for upper-extremity tumors and popliteal for lower-extremity tumors. Regional lymph nodes are defined as axillary/infraclavicular nodes for upper-extremity tumors and inguinal/femoral nodes for lower-extremity tumors.

Positron emission tomography (PET) scanning is recommended for evaluation and staging of extremity primary tumors before initiation of therapy [95] and is useful in RT treatment planning.[96]

For patients enrolled in clinical trials, the COG-STS recommends biopsy of all enlarged or clinically suspicious lymph nodes, if possible, without delay in therapy or adverse functional outcome. If biopsy is not feasible, clinically abnormal nodes need to be included in the RT treatment plan.

In the trunk and extremity, if no enlarged lymph nodes are identified in the draining nodal basin, a sentinel lymph node biopsy is recommended. This type of biopsy is a more accurate way of assessing regional lymph nodes than random lymph node sampling. Techniques for sentinel lymph node biopsy are standardized and should be completed by an experienced surgeon.[93,97-103]

In a single-institution study of 28 patients aged 6 months to 32 years with soft tissue sarcomas, but not confined to rhabdomyosarcoma, sentinel lymph node biopsy was prospectively compared with PET-CT scan for detection of lymph node metastases. Forty-three percent of patients (3 of 7) with proven malignant sentinel lymph nodes had negative cross-sectional and functional imaging (PET-CT). Also, PET-CT suggested nodal involvement in 14 patients, whereas only 4 of those were proven to have metastatic disease. The study does not address relapse rate or follow-up in these patients. Therefore, the use of PET-CT staging to diagnose lymph node disease in soft tissue sarcomas is of uncertain utility.[104]