From the Guidelines
Radiation therapy to periaortic lymph nodes should be delivered with a dose of 45-50 Gy for microscopic disease, and extended-field pelvic and para-aortic radiotherapy is recommended for patients with documented common iliac and/or para-aortic nodal involvement, up to the level of the renal vessels, as stated in the most recent guidelines 1.
Key Considerations
- The radiation field should encompass the periaortic lymph node chain from the renal vessels (T12-L1) down to the common iliac bifurcation (L5-S1) 1.
- Modern techniques like IMRT (Intensity-Modulated Radiation Therapy) or VMAT (Volumetric Modulated Arc Therapy) are preferred to maximize target coverage while minimizing exposure to surrounding organs including kidneys, small bowel, and spinal cord 1.
- Prior to treatment, CT simulation with IV contrast is essential for accurate lymph node delineation, and daily image guidance should be employed during treatment 1.
- Patients should be monitored for potential side effects including nausea, diarrhea, and fatigue, which can be managed with antiemetics like ondansetron 4-8mg every 8 hours as needed and loperamide 2mg after each loose stool.
Treatment Approach
- For patients with negative nodes on surgical or radiologic imaging, the radiation volume should include the entirety of the external iliac, internal iliac, and obturator nodal basins 1.
- For patients deemed at higher risk of lymph node involvement, the radiation volume should be increased to also cover the common iliacs 1.
- Concurrent cisplatin-based chemotherapy is given during EBRT for most patients with cervical cancer 1.
Recent Guidelines
- The 2019 guidelines from the National Comprehensive Cancer Network (NCCN) recommend extended-field pelvic and para-aortic radiotherapy for patients with documented common iliac and/or para-aortic nodal involvement 1.
- The guidelines also emphasize the importance of accurate lymph node delineation and daily image guidance during treatment 1.
From the Research
Radiation to Lymph Node Periaortic Staging
- The role of elective para-aortic lymph node irradiation in patients with locally advanced cervical cancer was examined in a study published in 2014 2. The study found that the addition of para-aortic lymph node radiotherapy to pelvic radiotherapy was not associated with a significant difference in disease-free survival or overall survival.
- A study published in 1986 3 found that extended-field radiation therapy for prostatic carcinoma with para-aortic lymph node metastasis can result in prolonged progression-free survival and perhaps cure many patients with juxtaregional dissemination of adenocarcinoma of the prostate.
- Radiation therapy for para-aortic lymph node metastases from uterine cervical cancer was evaluated in a study published in 2015 4. The study found that radiation therapy can effectively control para-aortic lymph node metastases in patients with uterine cervical cancer, and a total dose of 50.4 Gy in 1.8 Gy fractions is sufficient to control metastatic lymph nodes ≤ 25 mm in diameter.
- A study published in 2019 5 found that patients with isolated para-aortic lymph node recurrence after curative radiotherapy for cervical cancer had higher survival outcomes at 3 years, and histologic type, presence of symptoms, extent of disease, and disease-free interval were the prognostic factors for survival.
- The management of para-aortic lymph node metastasis in colorectal patients was reviewed in a systematic review published in 2016 6. The review found that para-aortic lymph node dissection for isolated para-aortic lymph node metastasis from colorectal cancer can be performed with minimal morbidity and confers a survival advantage, in comparison with conventional palliative chemotherapy or chemoradiation therapy.
Treatment Outcomes
- The 3-year overall survival rate for patients with para-aortic lymph node recurrence after curative radiotherapy for cervical cancer was 42.7% 5.
- The 5-year overall survival after metastatectomy for synchronous para-aortic lymph node metastasis in colorectal cancer ranged from 22.7% to 33.9% 6.
- The median overall survival for patients with metachronous para-aortic lymph node metastasis in colorectal cancer was 34-40 months for those who underwent para-aortic lymph node dissection, compared to 3-14 months for those who did not undergo dissection 6.