As the tumor grows, lower abdominal distension, abdominal masses and ascites may appear. The symptoms of late stage ovarian cancer are mostly caused by ascites, omentum or gastrointestinal metastasis, such as abdominal distension, shortness of breath, epigastric discomfort and symptoms of incomplete or complete intestinal obstruction. (ii) Physical signs Pelvic mass, ascites (iii) Laboratory tests Serum CA125, AFP, HCG levels are elevated. (iv) Imaging examination B ultrasound or CT indicates pelvic occupancy (v) Pathology Cancer cells are found in ascites. Stage I tumor is limited to ovary ⅠA tumor is limited to one ovary, without ascites, with intact peritoneum ⅠB tumor is limited to both ovaries, without ascites, with intact peritoneum and no tumor on the surface ⅠC stage ⅠA or ⅠB tumor with ruptured peritoneum, with tumor growth on the surface, and malignant cells found in ascites or abdominal washout Ⅱ tumor invades one or both ovaries, with pelvic metastasis ⅡA tumor invades Stage IIB Tumor invades ovary with metastasis to uterus and/or fallopian tube Stage IIB Tumor invades ovary with metastasis to other tissues Stage IIC Stage IIa or IIb Tumor envelope rupture, tumor growth on surface, malignant cells found in ascites or abdominal washings Stage III Tumor invades one or both ovaries with metastasis to peritoneal implant beyond pelvic and/or retroperitoneal lymph nodes, metastasis to inguinal lymph nodes, metastasis to surface of liver. Tumor confined to pelvis but with histologically confirmed invasion of small intestine and omentum ⅢA Tumor confined to pelvis with no lymph node metastasis and histologically confirmed peritoneal implantation ⅢB Peritoneal implantation metastasis ≤ 2 cm in diameter with no lymph node metastasis ⅢC Peritoneal implantation metastasis > 2 cm in diameter and/or retroperitoneal or inguinal lymph node metastasis Ⅳ Tumor invading one or both ovaries with distant metastasis, including ascites or pleural fluid Cytology found cancer cells, liver parenchymal metastasis III. Treatment (I) Treatment principles The treatment of ovarian malignant tumor should be a comprehensive treatment mainly based on surgery. Among the adjuvant treatment, chemotherapy is an important treatment tool. （The principle of surgery varies according to the individual patient’s condition, such as comprehensive exploration and staging of early-stage cancer and surgery to preserve reproductive function; surgery for advanced ovarian malignant tumors should be based on the principle of removing the tumor as much as possible, regardless of the size of the tumor and whether there is intra-abdominal metastasis, as long as the tumor can tolerate the surgery. This surgery is called cytoreductive surgery or tumor reduction surgery. Depending on the timing of surgery, it is divided into post-neoadjuvant chemotherapy reduction, interval reduction, second dissection, and second reduction for recurrent cancer. The residual tumor diameter ≤1cm after the completion of surgery is called the ideal surgery. Those with residual tumor diameter >1cm are suboptimal surgeries.