Study of distribution of inguinal nodes around the femoral vessels and contouring of inguinal nodes.

AIMS: To determine the distribution of inguinal nodes around the vessels, margins needed around the vessels and inferior extent of contouring in the inguinal region.

SUBJECTS AND METHODS: Fifty patients having pelvic malignancies with one or more malignant nodes in the inguinal region were retrospectively included in this study. The position of the nodes in relation to the vessels, size of the nodes, the distance from the center of the node to the edge of the nearest vessel was measured. Margins required to cover the nodes from the vessels and position of the nodes in relation to the lesser trochanter was noted.

RESULTS: Most of the nodes were placed either anteromedial (46%) or anterior (46.6%) to the vessels (92.6%). The range of margin required to cover all nodes in the anteromedial, anterior and anteriolateral direction varied from 0.8 to 2.7 cm. Only one node was more than 2 cm below the lower edge of lesser trochanter.

CONCLUSION: Elective clinical target volume for inguinal lymph nodes requires a minimum margin of 2.5 cm from the femoral vessels in the anterior, anterolateral and anteromedial direction 1.5 cm margin is required medially. Inferior extent of the contour should be 2 cm below the lower edge of lesser trochanter.