Lymphatic mapping for image guided radiotherapy in patients with locally advanced cercical cancer, a pilot study

Lymph node metastasis is an important unfavourable prognostic factor in locally advanced cervical cancer (LACC), thus preferably all lymph nodes with metastases should be included in the radiotherapy treatment plan. At our institution, the radiotherapy treatment plan consists of external beam radiotherapy of the pelvis, extended to the para-aortal region if there are evidently suspicious lymph nodes on imaging, histopathologically proven when feasible. An extra boost is given to the parametria when there is suspicion of parametrium involvement on imaging and/or during investigation under anaesthesia, and to suspicious lymph nodes. External beam radiotherapy is followed by additional brachytherapy to the primary tumour.
If no lymphadenectomy is performed, it can be challenging to prove lymph node metastases on imaging, especially micrometastases. Early recurrence of cervical cancer occurs most of the time in lymph nodes. This suggests that in a patient with lymph node recurrence, the radiation treatment was suboptimal: the nodes with recurrent disease were either not included in the radiation treatment plan or did not receive a sufficient radiation dose.
Lymphatic mapping is a procedure in which all lymph nodes with drainage from the primary tumor, i.e. all nodes with potential (micro)metastases, can be imaged. These nodes are not necessarily suspicious on other imaging techniques.
Objective:
The goal of this pilot study is to
1. investigate the feasibility of the lymphatic mapping procedure in locally advanced cervical cancer
2. study the agreement of the lymphatic map with the radiotherapy treatment plan including previous imaging (MRI / CT / FDG-PET/CT)

1. It is feasible to perform lymphatic mapping in locally advanced uterine cervical cancer. 2. There are lymph nodes on the lymphatic map which are not included in the radiation treatment plan or did not receive sufficient radiation dose.

Start date 20-07-2020.
Primary outcome: After completion of the 2nd lymphatic map imaging (1 day after inclusion).
Method: visual assessment. Visualisation of lymph nodes on both sides of the tumor is considered a positive outcome. Visualised nodes are nodes at risk.
Secondary outcome: After inclusion of all patients.
Method: the details of the RT treatment plan (location and dose of RT on lymph nodes; blinded to the lymphatic map) is retreived from the electronical patient chart. The RT data will be compared to the localisation of nodes at risk on the lymphatic map.