Unveiling the lymph node drainage route in stage IB1 to IIA2 cervical cancer: insights from a retrospective cohort study

This study aimed to identify the drainage route and the first station of lymph node metastasis (LNM) in patients with stage IB1 to IIA2 cervical cancer. The clinicopathological data of stage IB1 to IIA2 cervical cancer patients who underwent radical surgery between 2018 and 2022 were retrospectively retrieved and assessed. Hematoxylin and eosin-stained cervical cancer specimens, including cervix and lymph node tissues, were collected and reviewed independently by two pathologists blinded to the patients' clinical information. Of the 429 investigated patients, the mean number of lymph nodes removed per patient was 30, and the number of lymph nodes removed between the left and right pelvis was comparable. Additionally, of the 121 (28.2%) patients with LNM, the number of LNM between the left and right pelvis was comparable, and 64 (52.9%) patients had one area of LNM. The internal iliac lymph node was the primary area of LNM, followed by the obturator and external iliac lymph nodes. These three areas accounted for approximately 80% of all LNM cases. We also observed that in cases with LNM in any of these three areas, the second station of drainage area was fixed in more than 50% of patients. The most common first stations of LNM in stage IB1-IIA2 cervical cancer patients were found to be the internal iliac, obturator and external iliac lymph nodes in sequence, and complete removal of these lymph nodes is crucial for those without satisfactory or even failed sentinel lymph node mapping.