Ovarian cancer is the most deadly malignant tumor of female reproductive tract, with a current incidence rate of 8.14/100,000 and mortality rate of 3.13/100,000 in China. Due to the lack of effective early diagnosis methods, 70% of patients are already at advanced stage when they are first diagnosed, and treatment is quite difficult. Therefore, early diagnosis and standardized treatment have become the most important issues in the diagnosis and treatment of ovarian cancer. As reported by Powell et al. at the Society of Gynecologic Oncologists (SGO) 2011 meeting, an SGO Quality and Outcomes Committee study based on the National Cancer Database and including 144,449 patients found that adherence to NCCN guidelines for treatment was associated with improved survival in advanced ovarian cancer, but even in countries with relatively high levels of ovarian cancer care such as the United States, advanced However, even in countries with relatively high levels of ovarian cancer care, such as the United States, the rate of standardized treatment for advanced ovarian cancer is only 43.2%. The situation in China is even more worrisome. The inaccurate staging of early-stage ovarian cancer without lymph node dissection or removal of only pelvic lymph nodes leads to incorrect prognosis estimation and treatment selection, and a considerable number of patients are either under-treated or over-treated; the low satisfaction rate of initial tumor cytoreductive surgery for advanced ovarian cancer leads to more patients with chemotherapy resistance and poor prognosis; the treatment of recurrent ovarian cancer is even more confusing, and a considerable number of patients suitable for reoperation are deprived of surgical treatment. The treatment of recurrent ovarian cancer is even more confusing, and a considerable number of patients who are suitable for surgery again lose the best time for surgery, and chemotherapy seriously affects patients’ quality of life, and even death due to chemotherapy side effects happens from time to time. All these show that the standardized treatment of ovarian cancer needs to be strengthened. I. Surgical treatment of early-stage ovarian cancer Strictly speaking, the definition of early-stage ovarian cancer should be defined as ovarian cancer with stage I surgical pathological stage. Surgery should be preferred for early-stage ovarian cancer. The purpose of surgery is not only to remove the tumor, but also, very importantly, to clarify the diagnosis and stage. To distinguish it from tumor cell reduction in advanced ovarian cancer, the procedure is now commonly referred to as full staging surgery. It can be seen that the surgical nomenclature of ovarian cancer is basically based on the principle of surgery, which is tumor reduction in advanced stages, while the most important thing is accurate staging in early stages. To achieve accurate staging, the procedure usually includes abdominal irrigation fluid or ascites left after opening, full exploration and biopsy of suspicious areas such as the peritoneum; in addition, total hysterectomy, bilateral adnexal resection, major omentectomy (usually along the root of the transverse colonic mesentery), pelvic lymph node dissection and para-aortic lymph node dissection should be routinely performed. The latter NCCN guidelines emphasize that it should be performed at least to the level of the inferior mesenteric artery and preferably to the level of the renal vasculature. The appendix should also be routinely removed for epithelial carcinoma. In young, fertile patients with stage I tumors confined to one side at any grade, fertility can be preserved. However, the scope of surgery must meet the requirements for full staged surgery, except for preservation of the healthy adnexa and uterus, which is called staged surgery for preservation of reproductive function. Any abnormalities in the appearance of the preserved ovary should be dissected and require biopsy and frozen pathology if necessary. A completely normal appearance does not require dissection. Patients whose initial surgery is not fully staged should undergo another full staging procedure before chemotherapy is started to achieve full staging, called re-staging surgery. According to the NCCN guidelines, early-stage ovarian cancer with high and intermediate differentiation in stages IA and IB can be observed only without chemotherapy; some studies have reported that the rate of lymph node metastasis in ovarian cancer that appears to be stage I to the naked eye is as high as 25-30%. Re-staging surgery, on the one hand, has the potential to spare those truly early-stage patients from unnecessary chemotherapy; on the other hand, it also has the potential to screen patients with potentially advanced stages, achieve complete tumor reduction and avoid under-treatment. It is important to emphasize that it has been an accepted principle that the earlier the patient, the larger the surgery should be. Narrowing the scope of surgery or incomplete staging under any pretext other than the patient’s own difficulty in tolerating surgery is not standard treatment. If the required surgical scope cannot be reached due to technical reasons, it is best to transfer the patient to a hospital with the appropriate technical level before surgery; if the primary care physician unexpectedly encounters ovarian cancer during surgery, he or she may perform only competent surgery such as biopsy or adnexal resection, and transfer the patient to a higher level hospital for re-staging surgery before chemotherapy begins. Various staging and restaging procedures for early-stage ovarian cancer can also be done laparoscopically, provided that the tumor can be safely removed without affecting the staging; laparoscopic lymph node dissection of the abdominal aorta, at least up to the level of the inferior mesenteric artery, can be done in a standardized manner. If the so-called “minimally invasive” technique causes incomplete staging or even rupture of the tumor, it is unacceptable to change patients with IA or IB stage who do not need chemotherapy into IC stage who must be treated with chemotherapy, and thus cause great hidden danger and huge trauma to the patients. The ICON1 clinical trial in Europe confirmed the long-term efficacy of adjuvant chemotherapy on recurrence-free survival and overall survival of early-stage ovarian cancer after long-term observation. A total of 477 cases of early-stage epithelial ovarian cancer were included in the study, and at 10 years of follow-up, overall survival improved by 9% and recurrence-free survival improved by 10%, especially in high-risk patients, who showed a 17% improvement in overall survival and a 22% improvement in recurrence-free survival, without excluding the smaller benefit of adjuvant chemotherapy for intermediate- and low-risk patients. It is currently believed that after fully staged surgery, histopathologically confirmed stage IA and IB, highly differentiated patients can be treated without chemotherapy; those with intermediate differentiation can be observed or treated with chemotherapy according to the patient’s wishes. Otherwise, all patients with stage IC, hypofractionation, and histopathological types with poor prognosis such as clear cell carcinoma and carcinosarcoma should be treated with chemotherapy for 3-6 courses. the clinical trial of GOG157 specifically compared the efficacy and toxicities of 3 and 6 courses of chemotherapy. 457 patients with early-stage ovarian cancer were included in the study, of which 427 (93%) met the trial criteria. 69% were stage I The 6-course group had more severe toxicities and a 24% lower recurrence rate, with an expected 5-year recurrence rate of 20.1% (6-course) vs 25.4% (3-course) compared with the 3-course group, but no difference in overall mortality. Further stratified analysis showed that 6 courses prolonged survival in the high-risk type of early-stage ovarian cancer. Therefore, it is now generally accepted that 6 courses are preferable except for intermediate-risk patients. The chemotherapy regimen is the same as that for advanced ovarian cancer. Surgical treatment of advanced ovarian cancer Surgery should be preferred for advanced ovarian cancer. Since 2008, the NCCN guidelines have changed the criteria for satisfactory tumor cytoreduction from <2 cm to <1 cm residual lesion, and in the 2011 edition, it is emphasized that although the standard is set at <1 cm, it is better to achieve no visual residual. To achieve this, the satisfactory scope of tumor cytoreduction may include, in addition to the scope of full staging surgery described above, radical pelvic organ resection, diaphragmatic surface or other peritoneal surface tumor debulking, bowel resection, splenectomy, partial hepatectomy, cholecystectomy, partial gastrectomy, partial cystectomy, ureterocystic anastomosis, and pancreatic body and tail resection. In addition, it may include surgery for stage IV ovarian cancer such as supraclavicular lymph node dissection, thoracentesis and drainage, and excision of isolated skin metastatic lesions. After such surgeries, in principle, a clear diagnosis, comprehensive staging, and no residual meatus or satisfactory tumor load reduction should be achieved. The ratio of satisfactory tumor cell reduction to the initial treatment of all ovarian cancers should be the most important indicator of the level of ovarian cancer diagnosis and treatment in hospitals and countries. In recent years, the satisfactory rate of initial tumor cytoreduction for ovarian cancer has been mostly reported to be 45.5%-62.5%, and some experienced gynecologic oncologists have reported satisfactory tumor cytoreduction rates of 91%. Kehoe et al. have written that the success rate of the procedure is related to both the surgical skill of the attending surgeon and the experience of the entire team involved in the procedure. For patients with advanced disease who are considered to have no chance of satisfactory decompression at a lower level hospital, surgical satisfaction rates of 71%-76% can be achieved at a higher level institution. Therefore, they recommend that patients with advanced ovarian cancer should be seen by a medical institution that can achieve a satisfaction rate of 75% or higher. The satisfaction rate of initial tumor cytoreductive surgery for advanced ovarian cancer at the Gynecologic Oncology Center of Peking University People's Hospital was 89.3%. In the past 18 years, the overall ovarian cancer survival rate was 54.7%, all of which reached the international advanced level. NCCN guidelines suggest that for stage IV patients with distant metastases and stage III patients with large tumors that are difficult to achieve satisfactory reduction, a biopsy histopathological diagnosis can be obtained by laparoscopy or fine needle aspiration, or when a gynecologic oncologist with specialized training has a high suspicion of ovarian cancer and a positive cytological diagnosis by ascites aspiration, several courses of chemotherapy, i.e. neoadjuvant chemotherapy, should be administered first, followed by initial intermittent tumor cytoreduction. Neoadjuvant chemotherapy can reduce the difficulty of tumor cytoreduction, improve the satisfaction rate of surgery, and reduce the intraoperative and postoperative morbidity and mortality to some extent, but it does not prolong the survival of patients, and often results in higher incidence of drug resistance and prolong the overall treatment time of patients, thus causing a decrease in their quality of life. Therefore, neoadjuvant chemotherapy should not be used as the conventional treatment of choice for advanced ovarian cancer. However, neoadjuvant chemotherapy appears to prolong tumor-free survival in elderly patients with advanced ovarian cancer over 70 years of age. In the initial tumor cytoreductive surgery, if the cancer foci are found to have extensive pelvic and abdominal implantation and metastasis, and it is difficult to achieve satisfactory tumor reduction, an operation called "basic surgery" by the author can be performed, the scope of which should include at least bilateral adnexa and greater omentum. On the other hand, the primary site of the tumor (from the ovaries, fallopian tubes, or peritoneum) can be clarified, which is helpful for diagnosis and prognosis assessment. The NCCN guidelines also state that in patients with stage II-IV disease who have had incomplete initial surgery, complete tumor cytoreduction can be performed after 3-6 courses of chemotherapy if unresectable residual lesions are evaluated. Here, although the NCCN guidelines do not specify the name of this procedure, it should be similar in meaning to intermittent tumor cytoreduction as described by the author, and distinctly different from initial intermittent tumor cytoreduction performed after neoadjuvant chemotherapy as described above. The former is obviously chemotherapy based on a certain degree of tumor reduction, while the latter is only chemotherapy based on biopsy or even cytological diagnosis, which are not comparable. Although the former is also part of the initial treatment strategy for ovarian cancer, it is already in the realm of secondary surgery, whereas the latter is still in the realm of initial surgery. It is worth noting that whether intermittent tumor cell reduction can prolong survival is still controversial and cannot be used as a routine treatment for advanced ovarian cancer. However, the treatment model of basic surgery + chemotherapy + intermittent tumor cytoreductive surgery can be used as an alternative in cases where advanced ovarian cancer is unexpectedly encountered during surgery and the conditions of frozen pathology or satisfactory tumor reduction are not available, so that the patient has the opportunity to be transferred to a higher level hospital to complete standardized surgery. It is of great clinical significance today when the overall level of standardized surgery for ovarian cancer in China is still far from that of European and American countries. Chemotherapy for advanced ovarian cancer Chemotherapy is the most important adjuvant treatment for advanced ovarian cancer. In the 2011 Chinese edition of NCCN guidelines, four preferred chemotherapy regimens for ovarian epithelial cancer are recommended, namely paclitaxel + cisplatin, paclitaxel + carboplatin, docetaxel + carboplatin, and weekly therapy with paclitaxel, all of which are class I evidence. These four regimens, with essentially similar efficacy and all with Class I evidence, are still the actual currently accepted preferred monthly regimen of paclitaxel + carboplatin (TC), i.e., regimen 2, due to side effects and practical aspects, which causes fewer and milder acute toxic reactions to chemotherapy. The main dose-limiting toxicity is the hematologic toxicity such as grade III/IV platelet reduction, and the timely application of leukocyte- and platelet-raising drugs can effectively control such side effects. The paclitaxel + cisplatin (TP) regimen, although with the same efficacy as TC, has poor patient compliance due to more severe acute toxic reactions, such as nausea and vomiting, and a high incidence of irreversible side effects, such as severe peripheral neurotoxicity. The docetaxel + carboplatin regimen has a more severe hematologic toxic response than the TC regimen, but is generally used more often in patients who are more prone to neurotoxicity, such as those with diabetes, because of the milder peripheral neurotoxicity of docetaxel. Regimen 4, i.e., TC weekly therapy, has limited application at present due to weekly chemotherapy, which conflicts with our current chemotherapy often requiring hospitalization, and health insurance reimbursement policies. The evidence for the combination of other platinum analogues such as platinum oxalate, nedaplatin, and leuprolide with paclitaxel as first-line treatment is not sufficient and should not be the preferred regimen for the time being. Similarly, the combination of other paclitaxel classes, such as liposomal paclitaxel and albumin paclitaxel, with platinum should not be routinely preferred. However, patients should be encouraged to participate in well-designed formal clinical trials. Treatment of recurrent ovarian cancer Once ovarian cancer recurs, treatment is extremely difficult. Treatment of recurrent ovarian cancer is different from that of primary treatment, with chemotherapy often being the first choice, followed by surgery. However, the 2011 edition of NCCN guidelines emphasizes that for platinum-sensitive (complete remission for more than 6 months) recurrent ovarian cancer, assessment of whether surgery is still appropriate should be performed first, and secondary tumor cytoreduction should be given priority to patients who are suitable for surgical treatment. Because chemotherapy drugs always kill cancer cells in a certain proportion, it is theoretically impossible to kill tumor cells completely even if chemotherapy is effective. Only surgical resection can control the tumor fundamentally. The most important evaluation index of secondary tumor cytoreduction is whether the tumor can be cut cleanly. Some studies have reported that secondary tumor cell reduction for recurrent ovarian cancer is of limited value if no fleshly residue can be achieved. Therefore, the key to secondary surgery for recurrent ovarian cancer is preoperative evaluation, which requires a more experienced ovarian cancer specialist to be competent. This type of surgery is also quite complex and risky, and often requires the synergy of surgical teams from different departments to complete it successfully. If it is technically difficult to achieve, it is best not to venture into secondary surgery, otherwise it will not only be difficult to achieve the treatment goal, but also make the subsequent treatment unnecessarily difficult. Platinum-resistant type (complete remission less than 6 months) recurrent ovarian cancer is generally no longer suitable for surgery, except for a few special cases. The satisfaction rate of secondary tumor cytoreductive surgery for recurrent ovarian cancer at our center is 80%. Chemotherapy for sensitive recurrent ovarian cancer generally still advocates platinum-containing combination chemotherapy regimens, such as TC, carboplatin + liposomal adriamycin, cisplatin + topotecan, etc. For drug-resistant recurrent ovarian cancer, non-platinum single-agent chemotherapy is mostly used, such as topotecan weekly therapy and gemcitabine weekly therapy, etc. The common advantage of these two drugs is that they have no accumulation toxicity. If these patients can get some control of their tumors and maintain platinum-free treatment interval >1 year, it is possible to reverse platinum resistance. Usually, the longer the platinum-free interval, the higher the proportion of platinum re-sensitization, and at this time, it is still possible to obtain good efficacy by using platinum-based combination chemotherapy again. Of note is the group of patients with relapses between 6-12 months of complete remission, which was classified as partially sensitive relapses in the 2009 and 2010 editions of the NCCN guidelines and was eliminated in the 2011 edition, probably because the appropriate management response for this group of patients is not yet known. However, the prognosis of this group of patients is between the sensitive and resistant types, and our own study suggests that it may still be necessary to treat them differently, and that the management strategy should be closer to that of the resistant type. Oral VP16 capsules have a special place in the chemotherapy of recurrent ovarian cancer. Despite its good effect, this drug is generally not used prematurely because of its side effect of inducing leukemia. Studies have concluded that once even early-stage ovarian cancer recurs, the prognosis is as poor as that of late-stage ovarian cancer; while most recurrent ovarian cancer has no chance of cure, it is possible to achieve prolonged life, or long-term survival with tumor through standardized treatment. Therefore, how to control the tumor progression to a certain extent in the treatment of recurrent ovarian cancer, while maintaining a good quality of life for patients to the maximum extent should be a concern. To some extent, maintaining quality of life is the most important treatment purpose at this stage, and palliative treatment occupies an important position in opposition to blind treatment without regard to quality of life. Conclusion The standardized treatment of ovarian cancer is crucial to the prognosis. Comprehensive staging surgery is emphasized for early-stage ovarian cancer. For young patients with fertility requirements, stage I patients with tumors confined to one ovary and any grading, fertility can be preserved. For patients whose initial surgical staging is not comprehensive, restaging surgery should be performed before chemotherapy is started. Surgical pathologic staging for stages IA and IB, highly differentiated patients do not need chemotherapy; those with intermediate differentiation can be observed or treated with chemotherapy. All patients with stage IC, hypofractionation, and histopathological types with poor prognosis such as clear cell carcinoma and carcinosarcoma should be treated with chemotherapy for 3-6 sessions. Surgical treatment should be preferred for advanced ovarian cancer as much as possible. Satisfactory tumor cytoreduction is the basis for better outcome. Neoadjuvant chemotherapy should not be used as a routine treatment option for advanced ovarian cancer. The model of basic surgery + chemotherapy + intermittent tumor cytoreductive surgery has some clinical practical significance. Paclitaxel + carboplatin is the first-line chemotherapy regimen. The treatment of recurrent ovarian cancer emphasizes more on individualization. Emphasis should be placed on the surgical treatment of recurrent ovarian cancer, the selection of second- and third-line chemotherapy regimens should be planned, and the treatment should take into account the patient’s quality of life.