Aims: To describe the distribution of enlarged lymph nodes by nodal group found radiologically in patients presenting with adenocarcinoma of the prostate. This will help to define which nodal groups should be treated during the pelvic radiotherapy of patients with less advanced disease.
Materials and methods: The scans of 55 men presenting with prostate cancer and metastases to lymph nodes only were reviewed. Lymph nodes of 8 mm or more in size were considered to be enlarged.
Results: The medial external iliac (obturator) nodes were most commonly enlarged (75% of patients) followed by nodes in the para-aortic region (26%) and anterior internal iliac region (24%). Para-aortic lymph-node enlargement was uncommon in the absence of pelvic lymphadenopathy. Midline pre-sacral lymph-node enlargement was not observed. Incidence of enlarged lymph nodes in the lateral external iliac group was 18%, an area which may not be routinely included during radiotherapy.
Conclusion: There is a case for studying further the role of including lateral external iliac lymph nodes in the pelvic radiotherapy volume, as there may be an appreciable risk of lymph-node spread to this area.