Metastasis to para-aortic lymph nodes cephalad to the renal veins in patients with ovarian cancer

The subjects of this study were patients with an initial diagnosis of epithelial ovarian cancer, primary peritoneal cancer, or fallopian tube cancer who underwent extended PAN dissection and pelvic lymph node dissection at Toho University Ohashi Medical Center.

The eligibility criteria for our surgical procedure were as follows: (1) preoperative Eastern Cooperative Oncology Group (ECOG) Performance Status of 0–1; (2) adequate major organ function as evaluated by hematology tests, biochemical tests, coagulation tests, chest and abdominal X-ray examination, and electrocardiography; and (3) written informed consent to surgery provided by the patient. Patients who met any of the following criteria were excluded: (1) a history of intestinal obstruction, (2) uncontrolled diabetes or hypertension, (3) deep venous thrombosis, (4) pancreatic disease, (5) a desire to preserve fertility, (6) borderline malignant tumor, and (7) active double cancer.

The chest and abdomen, including the supra-renal PANs, were examined carefully by computed tomography (CT) before surgery. Staging laparotomy was performed in patients with a clinical diagnosis of early cancer, while primary debulking surgery (PDS) was done in patients with a clinical diagnosis of advanced cancer in whom it was considered that primary surgery would achieve an optimal outcome. In addition, interval debulking surgery (IDS) was performed after 3–4 cycles of neoadjuvant chemotherapy (NAC) with taxanes, platinum, and bevacizumab in patients with clinically suspected advanced cancer in whom it was considered that primary surgery would not be optimal.

After pelvic lymph node dissection was completed, Komiyama’s maneuver for extended PAN dissection was carried out as follows (Fig. 1).

(1) The ascending colon was displaced from the right paracolic gutter toward the left side. A retroperitoneal incision was made from the ileocecal region in the cephalic direction along the so-called Monk’s white line on the dorsal side of the ascending colon. At this site, Gerota’s fascia, the ascending mesocolon, and the retroperitoneum coalesce to form the so-called fusion fascia, which continues to the mesentery on the right side of the second part of the duodenum and ends superiorly at the epiploic foramen on the inferior surface of the left lobe of the liver. The fusion fascia was incised through the medial side of Gerota’s fascia toward the root of the right renal vein to separate the right kidney from the ascending colon, which was mobilized to expose the region from the anterior surface of the inferior vena cava (IVC) to the left side of the abdominal aorta. The right ovarian vein runs through the fusion fascia and then through the pelvic cavity toward the midpoint of the IVC, and the right ureter also runs through the fusion fascia, allowing both structures to be easily identified by incising the fascia. After identifying the right ovarian vein, it was transected to expose the IVC below the renal vein (Fig. 1a–c).

(2) Kocher’s maneuver was performed for mobilization of the duodenum. The second part of the duodenum was displaced toward the left side and the incision in the fusion fascia, which was at the root of the right renal vein, was extended to the epiploic foramen. Then, connective tissues were stripped from around the duodenum, and it was mobilized to completely expose the IVC below the inferior surface of the left lobe of the liver (Fig. 1d, e).

(3) A retroperitoneal incision was commenced near the bifurcation of the abdominal aorta into the common iliac arteries and was continued along the medial border of the inferior mesenteric vein toward the ligament of Treitz, allowing complete mobilization of the small intestine and the right hemicolon. After mobilization, the small intestine and right hemicolon were placed in an isolation bag and lifted out of the abdominal cavity to clearly expose the whole aortic region from the superior mesenteric artery to the common iliac artery (Fig. 1f–i).

(4) The right and left renal arteries and the left inferior adrenal vein were identified, taking care to avoid damaging these vessels. When the left high para-aortic lymph nodes were dissected, care was also taken to avoid damaging the left adrenal gland, which is embedded in fatty tissue and is difficult to distinguish from a lymph node. The high para-aortic lymph node region contains important lymphatic channels, including the lumbar lymphatic trunk, the intestinal lymphatic trunk, and the chyle cistern. These structures must be managed carefully to prevent damage that could lead to leakage of chyle and occurrence of chylous ascites. Accordingly, both a vessel sealing system and a vascular clip (double ligation) were employed to prevent such events (Fig. 1j–l). While paying attention to these points, the para-aortic lymph nodes were dissected in the following order (Fig. 2):

The target region for supra-renal PAN dissection was bounded by the inferior surface of the left lobe of the liver (superiorly), the right border of the IVC (to the right), the medial border of the left adrenal gland (to the left), and the left inferior adrenal vein (inferiorly). Figure 3 shows an intraoperative view after systematic lymph node dissection.

Before the incision was closed, a hyaluronate carboxymethyl cellulose membrane (Seprafilm ®, Sanofi, Paris, France) was placed into the abdominal cavity to prevent postoperative adhesions and drains were inserted into the abdominal cavity. Cefmetazole was administered from the day of surgery until postoperative day 2 to prevent postoperative infection. Low-dose opioid infusion was provided via an epidural catheter until postoperative day 4 for pain management. Subcutaneous administration of enoxaparin sodium (Clexane ®, Sanofi) was started on postoperative day 2 and continued until postoperative day 7 to prevent postoperative deep venous thrombosis or venous thromboembolism.

This was a single-center retrospective study. The following patient characteristics and perioperative data were obtained from the medical records: the age, primary tumor site, FIGO stage, tumor histology, serum CA-125 level immediately before surgery, presence or absence of supra-renal PAN measuring ≥ 1 cm on CT before initiation of treatment, presence or absence of ascites at laparotomy, timing of surgery (PDS or IDS), curability of surgery and maximum residual tumor diameter, postoperative Union for International Cancer Control (UICC) pTNM classification (the ypTNM classification was used in patients who received NAC), postoperative duration of hospitalization, operating time, intraoperative blood loss, perioperative complications (from the day of surgery to postoperative day 30), number of dissected lymph nodes, number of metastatic lymph nodes, and locations of metastatic lymph nodes. Formalin-fixed, paraffin-embedded sections of the all dissected lymph nodes were made tissue specimens with the largest section and stained with hematoxylin and eosin. All dissected lymph nodes were examined histologically by pathologists, and metastatic nodes were diagnosed pathologically. When the presence of carcinoma in the parenchyma of the lymph node was observed microscopically, it was diagnosed as lymph node metastasis (Fig. 4). Intraoperative and postoperative complications were evaluated according to the Common Terminology Criteria for Adverse Events (CTCAE) Version 4.03 [4].

This study was conducted in compliance with the Declaration of Helsinki, and the protocol was approved by the ethical committee of Toho University Ohashi Medical Center (approval number H-17044). Informed consent was waived by the board due to the retrospective design of this study.