Endometrial carcinoma (EC) is a common gynecologic malignancy, occurring in approximately 5% of cases in women of childbearing age under 40 years. The primary treatment is total hysterectomy with bilateral adnexal resection or concomitant retroperitoneal lymph node dissection. However, as women worldwide are getting ready to conceive later and people’s demand for quality of life is increasing, the treatment for young endometrial cancer patients should not only aim to reduce recurrence and prolong survival, but also to maximize the quality of survival and preserve physiological functions or even fertility on the basis of ensuring prognosis. Although there are reports about the successful pregnancy achieved with fertility preservation treatment for endometrial cancer, which brings hope to such patients, there are still many unresolved issues, including: the safety of fertility treatment and pregnancy rate after treatment, the risk of ovarian tumor in preserving physiological function, and whether hormone replacement therapy can be performed after medically induced menopause. 1. Safety of fertility preservation therapy for young endometrial cancer patients The ideal outcome of fertility preservation therapy for endometrial cancer patients should be to achieve successful pregnancy without the adverse outcomes caused by tumors. Will conservative drug therapy delay treatment and affect prognosis? Due to the slow progression of endometrial cancer and the emphasis on monitoring of endometrial biopsy during diagnosis and treatment, recalcitrant cases that do not respond well to progestin therapy can be detected in time for timely surgical removal of the uterus, and the prognosis will not be affected. Therefore, none of the patients with highly differentiated endometrial cancer with poor response to drug therapy and timely hysterectomy reported in the literature died [1].Kaku et al. reported two recurrences in nine patients with endometrial cancer treated effectively with conservative therapy, including one with left-sided closed lymph node involvement and another in remission after re-treatment with MPA, who was able to get pregnant (but had an early-onset miscarriage) and had a first relapse 87 months after the first treatment, and finally a hysterectomy was performed and no residual lesions were found. However, there have been reports of residual lesions being found at the time of surgery, after delivery. In addition, despite the belief that full-term pregnancy is protective of the endometrium, pregnancy combined with endometrial cancer has been reported. Moreover, patients may have developed high-grade lesions, myxoid infiltration, lymph node metastases, ovarian malignancies (concurrent or metastatic), or metastatic disease during or after treatment, delaying the underlying surgical treatment and worsening the prognosis [2]. Therefore, long-term follow-up after treatment to preserve fertility requires close monitoring not only for local recurrence of uterine lesions, but also for the presence of concurrent ovarian tumors. Vaginal ultrasound, hysteroscopy or endometrial curettage should be performed every 3-6 months, and any suspicious symptoms or signs should be seen at any time for ultrasound or other imaging examinations for early detection of recurrence and reduction of distant morbidity and mortality. 2. Fertility issues after fertility preservation treatment for young endometrial cancer patients Pregnancy is the ultimate goal of fertility preservation treatment, however, it is difficult to determine the pregnancy rate after successful fertility preservation treatment for endometrial cancer patients because these patients usually have other factors that affect fertility, such as obesity, polycystic ovary syndrome and long-term anovulation. The key to addressing fertility is how to induce ovulation quickly, safely and effectively: clomiphene, GnRH pulse therapy, laparoscopic ovarian drilling, and aromatase inhibitors such as letrosole to promote ovulation [3]. In addition, the application of assisted reproductive techniques, in vitro fertilization-embryo transfer (IVF-ET), has the advantage of being expected to solve fertility problems in a limited time frame. After complete remission of endometrial cancer has been confirmed by diagnostic scraping, for those who are eager to have children, natural pregnancy can be attempted if the patient has no history of infertility, and those who are still not pregnant at 3 months, tests related to infertility are performed or assisted reproduction is performed accordingly based on the evaluation of the fertility of both partners. In patients with a history of infertility and anovulation, ovulation induction should be initiated once complete remission of endometrial cancer is confirmed, as there is no evidence that ovulation-inducing drugs (e.g., clomiphene) can cause an increased risk of developing endometrial cancer. Although information on the outcome of assisted reproductive technologies (ART) after conservative treatment of endometrial cancer is limited, ART does not affect the prognosis. Not only is there no evidence that high-dose gonadotropins used for IVF increase the risk of recurrence of endometrial cancer, but ART may also increase the chance of successful pregnancy and shorten the interval between pregnancies. For reluctant pregnancies, maintenance therapy with oral contraceptives, cyclic progestins, long-acting MPA or progestin-containing IUDs is recommended, and ultrasound evaluation of the endometrium and D&C should be performed periodically. levonorgestrel IUD has recently been reported to be a good inhibitor of endometrial hyperplasia [1]. Although the effectiveness of progestin IUD in endometrial cancer remains unclear, it could be an alternative to estrogen-progestin therapy during observation in reluctant pregnant patients. Ushijima et al. reported the use of infertility treatment in 11 of 12 pregnancies, including 5 cases of IVF-ET. It was also reported that 55% of the 17 pregnancies obtained after progestin therapy were successful by IVF. Thus, it seems that most patients with endometrial cancer were treated conservatively with infertility treatment before obtaining a successful pregnancy, including assisted conception techniques. Therefore, only multidisciplinary (reproductive endocrinology, gynecologic oncology and perinatal medicine) comprehensive treatment can lead to a satisfactory pregnancy outcome in these patients. 3. risk of ovarian malignancy in young patients with endometrial cancer Young patients with endometrial cancer are at risk of coexisting adnexal disease, including primary ovarian tumors as well as tumors metastatic from endometrial cancer to the ovary [2]. In women of childbearing age, the chance of metastasis of clinical stage I endometrial cancer to the ovary is rare, about 5%. However, the odds of concurrent presence of ovarian malignancy in any stage of endometrial cancer are as high as 10-29%, at least 5 times higher than in patients over 45 years of age with endometrial cancer in combination with ovarian tumors (2-4.6%). Although younger patients with endometrial cancer and ovarian malignancy usually have enlarged ovaries, it is also possible to have occult ovarian tumors. Recently, several studies have reported the occurrence of ovarian malignancies in young patients with endometrial cancer.Walsh et al. retrospectively reviewed 102 patients aged 24 to 45 years with hysterectomized endometrial cancer and found that 26 (25%) had ovarian malignancies, 23 of which were coexisting primary ovarian tumors. Of the adnexa with normal preoperative imaging, 9% (4/46) were found to have ovarian malignancy; of the 16 patients whose ovaries were preserved at surgery, three ovarian abnormalities (two benign and one malignant) were found at the time of the second surgery. In addition, Yang et al. reported that 4 of 6 patients with highly differentiated endometrial cancer with normal pre-treatment evaluation did not respond to progestin therapy, and all 4 patients were found to have ovarian malignancy at the time of surgery. yamazawa et al. reported that 2 of 9 patients with endometrial cancer treated with progestin developed endometrial malignancy 10 and 22 months after obtaining complete histological remission of the endometrium and discontinuing progestin therapy. In addition, Morice et al. reported a case of a young endometrial cancer patient with normal pelvic and abdominal ultrasound. abdominal ultrasonography was normal and MRI suggested superficial myxomatous infiltration, and surgery was chosen, which revealed a moderately differentiated ovarian cystic adenocarcinoma with focal peritoneal lesions, again emphasizing the need for surgical exploration or laparoscopy prior to conservative treatment of highly differentiated endometrial cancer. Highly differentiated endometrial cancer is not expected to be free of adnexal disease, and tumor marker levels prior to treatment are not reliable; therefore, patients with endometrial cancer suitable for conservative treatment should be carefully selected, and a thorough evaluation of the adnexa by pelvic ultrasound, MRI, CA125, and even surgical exploration is needed, even if these tests are not perfect [4,5]. 4. the problem of hormone replacement therapy after medically induced menopause in young endometrial cancer patients Because endometrial cancer is an estrogen-dependent tumor, bilateral adnexa are routinely removed simultaneously during surgery. However, ovaries are important endocrine organs and the hormones they secrete have important physiological effects on urinary, reproductive system, breast, bone, glycolipid metabolism and cardiovascular. Young patients with ovariectomy will gradually develop vasodystrophic symptoms, genitourinary tract atrophy symptoms and osteoporosis, which will have a serious impact on the patient’s quality of life. Some experts give hormone replacement therapy (HRT) with continuous estrogen and progestin or estrogen alone to young endometrial cancer patients who have undergone total hysterectomy with both ovaries, and claim that HRT does not affect the survival time of patients. However, since endometrial cancer is a hormone-dependent malignancy that responds to both endogenous and exogenous estrogens, the question of whether exogenous estrogens will stimulate the growth of occult tumor cells after endometrial cancer surgery, shorten the survival time with tumor, promote recurrence, and reduce the survival rate has long been a concern for the application of hormone replacement therapy after endometrial cancer surgery. In 1986, Creasman et al. firstly reported the combination of estrogen therapy after surgery for stage I endometrial cancer (clinical stage), and concluded that estrogen replacement therapy was not a contraindication for patients with a history of endometrial cancer. Most of the studies concluded that the application of HRT did not affect the recurrence rate and survival rate of endometrial cancer after surgery. From the results of existing clinical studies, endometrial cancer is not an absolute contraindication to HRT. Since there is a lack of definite evidence of evidence-based medicine on the pros and cons of HRT or hormone therapy (TH) application in postoperative patients with endometrial cancer, and almost all estrogen preparations used for hormone therapy clearly state in their drug instructions that endometrial cancer is an absolute contraindication to the use of the drug, it is necessary to have very clear indications for its application, and secondly, HRT should be explained to patients and their families The role, risks, optional drugs and their side effects, and the length of treatment should be explained to patients and their families, and they should fully communicate with them to achieve informed consent. In addition, patients should have better follow-up conditions, and they should be followed up closely. 5. Over- and under-treatment of young endometrial cancer found accidentally Clinically, we often encounter cases of endometrial cancer reported by pathology after surgery, and it is worth paying attention to how to handle them correctly and avoid over- and under-treatment. The problems usually encountered are whether to operate again to remove both ovaries and whether to operate again to remove the pelvic and para-abdominal aortic lymph nodes. In principle, according to the endometrial cancer diagnosis and treatment standard, if indicated, endometrial cancer staging surgery should be performed to avoid under-treatment. Of course, if the indication is not strong and there is good follow-up, staging surgery is not necessary, especially for young patients, to avoid overtreatment. In conclusion, as the proportion of young endometrial cancer patients continues to increase, individualized treatment should be provided to these patients to meet their fertility requirements and improve their quality of life. However, it should be noted that because the treatment of young patients differs from the standard treatment of endometrial cancer and most studies are retrospective small sample case studies and case reports, there are still some debatable issues in the treatment of young endometrial cancer patients and a large multicenter prospective study on the treatment of young endometrial patients is needed to help develop appropriate treatment protocols and determine the safety of treatment. and to determine the safety of treatment.