OBJECTIVE: To investigate the method and significance of retroperitoneal lymph node dissection during staging exploration for ovarian epithelial carcinoma. METHODS: The clinical data of retroperitoneal lymph node dissection in 48 patients with staged ovarian cancer were retrospectively analyzed. RESULTS: The rate of retroperitoneal lymph node metastasis was 39.6% (19/ 48), of which 15.4% (2/ 13), 22.2% (2/ 9), and 57.6% (15/ 26) were in stages I, II, and III, respectively, and 4 patients in stages I and II had lymphatic metastasis and were upgraded to stage IIIc. The lymph node removal under the renal vein was significantly more difficult than the lymph node removal under the inferior mesenteric artery, with significantly longer operation time, more bleeding, and longer postoperative bowel function recovery. Conclusion: Retroperitoneal lymph node dissection is not only a prerequisite and necessary condition for accurate staging of ovarian cancer, but also a treatment tool. In recent years, lymphatic metastasis has been emphasized as an important route of metastatic spread of ovarian cancer, and it has become one of the main elements of the International Federation of Gynecology and Obstetrics (FIGO) surgical pathological staging of ovarian cancer. We performed retroperitoneal lymph node dissection in 48 cases of epithelial ovarian cancer, and discussed the significance, scope and surgical considerations of these cases. The histopathological types were: 27 plasma carcinoma, 8 endometrioid carcinoma, 7 mucinous carcinoma, 5 clear cell carcinoma, and 1 other carcinoma; the degree of histodifferentiation was: 9 highly differentiated, 12 moderately differentiated, and 27 poorly differentiated; the patients’ ages ranged from 21 to 67 years, with a median age of 52 years. After intraoperative rapid pathological examination to confirm ovarian cancer, total hysterectomy, double adnexa, greater omentum and appendix were performed, and retroperitoneal lymph node removal was performed. 27 cases underwent parietal aortic and pelvic lymph node removal at the origin of the inferior mesenteric artery (A-level removal), and 21 cases underwent lymph node removal at the origin of the inferior renal vein (B-level removal). The right hemi-colon was separated from the posterior abdominal wall and turned to the left upper abdomen together with the small intestine; the lymph nodes were cleared from the inferior mesenteric artery at the A level. The lymph nodes were cleared at the A level from the inferior mesenteric artery downward and the ureter medially on both sides; the lymph nodes were cleared at the B level up to the lower edge of the renal vein and the hilum and ureter medially on both sides; the order of clearance: from top to bottom, the lymph nodes next to the abdominal aorta, bilateral common iliac, presacral, external iliac, deep inguinal, internal iliac and closed foramen lymph nodes were cleared in turn. 3. Observation indexes: lymph node clearance time and bleeding volume, surgical complications, and lymph node metastasis. Results 1.Surgery and complications: the average time of surgery: about 1 hour and 45 minutes for A level clearance, 2 hours and 45 minutes for B level, and up to 4 hours for the longest case; blood loss: 150-450 ml for A level, 220 ml on average, 250-600 ml for B level, 350 ml on average, and up to 1300 ml; vascular injury: 2 cases of external iliac vein, 1 case of common iliac vein, 5 cases of inferior vena cava Five cases, including two cases of bleeding from inferior vena cava fissure caused by tearing of the nameless vein, were repaired with 6-0 vascular sutures and completed the operation as planned; one case of ureteral injury. The average recovery of bowel function was 2-3 days in the A-level area and 3-5 days in the B-level area after surgery, and no abdominal para-aortic lymphatic cysts were seen. 2. Lymph node metastasis: According to the surgical-pathological staging criteria (1988), there were 13 cases of stage I, 9 cases of stage II, and 26 cases of stage III. The metastasis rate of stage I was 15.4% (2/ 13); stage II was 22.2% (2/ 9); stage III was 57.7% (15/ 26), total 19 cases had lymph node metastasis, the metastasis rate was 39.6% (19/ 48), pelvic 37.5% (18/ 48), abdominal aorta 16.6% (8/ 48). The significance of retroperitoneal lymph node clearance: lymphatic metastasis is an important way for ovarian cancer to spread, and it is reported in the literature that it is 30% to 60%, Allen et al[2] reported that retroperitoneal lymph node dissection increased clinical staging in about 17% of patients, resulting in more rational and adequate treatment, and Onda et al[3] reported that in 67 stage I and II patients, after pelvic and para-aortic lymph node dissection, 14 patients increased their staging to stage IIIc, and their 5-year survival rate was similar to that of stage I and II patients, but higher than that of other stage III patients. The 5-year survival rate was similar to that of stage I and II patients and higher than that of other stage III patients. Lang Jinghe [4 ] reviewed the opinions of many foreign scholars and concluded that lymph node metastases do not respond to systemic chemotherapy and treatment mainly relies on surgical removal; Zinzindohoue et al [5 ] reported that the occurrence of lymph node metastases is basically the same before and after chemotherapy and concluded that the role of retroperitoneal lymph node dissection is its ability to remove lymph node metastases that cannot be reached by chemotherapy drugs. Therefore, retroperitoneal lymph node dissection is not only a prerequisite and necessary condition for accurate staging, but also a therapeutic tool that can not only remove metastatic lymph nodes and achieve the purpose of tumor reduction, but also enable patients who were originally considered early stage to receive reasonable diagnosis and adequate treatment. Adequate treatment. 2, the scope of retroperitoneal lymph node removal: the scope of retroperitoneal lymph node removal has not been completely unified, some perform lymph node removal at the beginning of the inferior mesenteric artery [6,7 ], some up to the level of the renal vein [1 ]. In our group, 21 cases underwent lymph node dissection at the level of the renal vein, which is significantly more risky and difficult than that at the level of the inferior mesenteric artery, with longer operation time, more bleeding, more time for postoperative bowel function recovery, and more complications, and the status of lymph nodes at the level of the inferior mesenteric artery can already reflect the presence or absence of metastasis in the main abdominal lymph nodes. If there is no clear lymph node enlargement, lymph node removal at the level of renal vessels is generally not recommended. (1) familiar with retroperitoneal anatomy, especially the distribution and direction of blood vessels and ureters, and pay attention to the possible variants; (2) careful operation When performing lymph node removal of the parietal aorta, pay attention to the nameless vein on the inferior vena cava to avoid bleeding from the tearing of the inferior vena cava, which caused nearly 300 ml of bleeding in one case in our group. (3) Correctly deal with all kinds of vascular bleeding, small veins bleeding, can be compressed to stop bleeding, while large veins should be repaired, this group of 8 cases of injury, all a successful repair, arterial wall is thicker, not easy to damage, such as bleeding, large arteries should be repaired, small arteries are ligated; (4) good psychological quality, in the event of large vessel bleeding, should be calm and composed, do not blindly clamp, otherwise easy to cause further damage to the vein wall, should be in After applying non-invasive vascular instruments to control bleeding, perform vascular repair. (5) Make adequate preoperative preparations, prepare all kinds of instruments that may be used such as vascular surgery kits, and preoperative imaging can help to determine the condition of retroperitoneal lymph nodes and help to estimate the difficulty of surgery.