Application of Lymphangiography in Para-Aortic Lymphadenectomy for Ovarian Cancer
Epithelial ovarian cancer (EOC) represents the most prevalent form of ovarian malignancy, with staging surgeries incorporating para-aortic and pelvic lymphadenectomy as a standard recommendation in both FIGO (2018) and NCCN (2019) guidelines. Despite its diagnostic and therapeutic benefits, this approach elevates risks of complications such as vascular injuries, intraoperative blood loss, and postoperative lymphatic disruptions, including chylous leakage. This study explores a novel method utilizing preoperative oral peanut oil to enhance intraoperative visualization of lymphatic structures, aiming to reduce postoperative chylous complications.
Clinical Context and Rationale
The radical removal of pelvic and para-aortic lymph nodes up to the renal vessels is integral to ovarian cancer staging and treatment. However, the procedure’s complexity introduces risks of damaging critical lymphatic pathways, particularly the intestinal trunk, which transports dietary lipids absorbed by intestinal villi. Injury to these structures during lymphadenectomy often results in chylous leakage, characterized by milky peritoneal drainage, elevated triglycerides (≥110 mg/dL), and daily fluid volumes exceeding 200 mL. Such complications prolong recovery, increase infection risks, and compromise patient nutrition and immunity.
Traditional intraoperative identification of lymphatic vessels is challenging due to their low-pressure, translucent fluid content, especially after preoperative bowel cleansing. This study hypothesizes that preoperative ingestion of peanut oil, rich in long-chain fatty acids, could opacity lymphatic fluid, enabling surgeons to visualize and avoid critical structures during dissection.
Study Design and Methodology
A retrospective analysis was conducted on 103 ovarian cancer patients undergoing para-aortic lymphadenectomy (up to renal vessels) and pelvic lymphadenectomy between January 2017 and December 2019. Patients were stratified into two groups: 52 received 60 mL of oral peanut oil 10 hours preoperatively, while 51 served as controls. Ethical approval was obtained, and all surgeries were performed by a consistent surgical team to minimize variability.
Key inclusion criteria encompassed histologically confirmed EOC, while exclusion criteria prioritized cases with preoperative lymphatic abnormalities or contraindications to peanut oil. Postoperative chylous leakage was diagnosed based on drainage characteristics, triglyceride levels, volume thresholds, and exclusion of infectious causes.
Outcomes and Observations
The intervention group exhibited a significantly lower incidence of chylous leakage compared to controls (3.85% vs. 15.69%, P = 0.042). Among the 10 cases of leakage, serous carcinoma predominated (8 cases), followed by clear-cell carcinoma and carcinosarcoma (1 case each). Leakage onset averaged 6.02 ± 2.35 days postoperatively, managed via ligation, electrocautery, Hemolok clips, biologic glue, or absorbable packing.
Lymphatic visualization was successful in 98.08% of the intervention group, revealing distinct anatomical patterns:
- Intestinal Trunk Distribution: 86.54% of cases showed chylous vessels above the inferior mesenteric artery (IMA), near the left renal vein.
- Variants: 5.77% exhibited crossing vessels over the aorta and inferior vena cava, extending into the right pelvis.
- Aortic Surface: 73.08% had lymphatic networks below the duodenal level on the aortic surface.
Macroscopically, peanut oil ingestion rendered lymphatic capillaries as white, grid-like structures along the small intestine mesentery (Figure 1A), with the intestinal trunk appearing as a milky-white cord in the para-aortic region (Figure 1B). This contrast allowed precise intraoperative identification, enabling prophylactic ligation or coagulation of vulnerable vessels.
Mechanistic Insights and Technical Advantages
Peanut oil’s high oleic acid content facilitates rapid intestinal absorption and incorporation into chylomicrons, which distend lymphatic vessels and increase fluid opacity. This transient lymphangiography effect peaks within 10 hours, aligning with surgical timing. Enhanced visualization aids in distinguishing lymphatic from vascular structures, reducing unintended injuries. Notably, the intestinal trunk’s typical location—left of the aorta, above the IMA—aligns with high-risk zones for iatrogenic injury during para-aortic dissection.
The study underscores the importance of meticulous lymphatics mapping, particularly in advanced disease (68.93% stage III/IV cases), where extensive dissection increases complication risks. By preemptively identifying and securing chylous pathways, surgeons mitigate postoperative leakage, aligning with recommendations for selective lymphadenectomy tailored to disease stage.
Clinical Implications and Future Directions
These findings advocate for preoperative peanut oil administration as a low-cost, accessible adjunct to ovarian cancer surgery. Its integration into surgical protocols could standardize lymphatic mapping, complementing emerging techniques like sentinel lymph node (SLN) biopsy. Future research should prospectively evaluate combined approaches—SLN mapping with dynamic lymphangiography—to refine dissection boundaries, minimize tissue removal, and further reduce morbidity.
Additionally, subgroup analyses by histology (e.g., higher leakage rates in serous carcinoma) may guide personalized risk stratification. Investigating optimal dosing, timing, and lipid compositions could enhance visualization efficacy while addressing potential allergies or gastrointestinal intolerance.
Conclusion
Preoperative oral peanut oil significantly enhances intraoperative visualization of para-aortic lymphatic structures, reducing chylous leakage incidence in ovarian cancer lymphadenectomy. This technique offers a pragmatic solution to a persistent surgical challenge, emphasizing the value of anatomical precision in oncologic outcomes. As minimally invasive and precision strategies evolve, such adjuncts will play a pivotal role in balancing radicality with patient safety.
doi.org/10.1097/CM9.0000000000001087
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