With increasing incidence of EC in younger women, increasingly women are likely to seek conservative management options. Progestin therapy is widely accepted as the main fertility-sparing treatment for young women with AEH and well-differentiated EC and acquire satisfactory results(5–7). However, there are still about 20% of these patients who failed to achieve CR, and lost fertility after hysterectomy(11). Side-effects or contraindications of progestins, such as weight gain or liver dysfunction call for alternative regimes other than oral high dose progestins.(12) .
GnRHa is a group of synthetic compounds which are derived from natural GnRH through substitution of amino acids at position 6 and/or 10(13). Some studies revealed that GnRHa can affect endometrial cell proliferation not only through the hormonal axis indirectly, but also by acting on the GnRH receptors directly(14, 15). Therefore, GnRHa could be used in the treatment of endometrial diseases due to its antiproliferative effect on endometrial cells. But the use of GnRHa is still experimental and did not achieve clinical practice. The application of GnRHa for endometrial diseases was initially reported for the management of patients with recurrent EC, resistant to other treatment modalities, with a regression rate as high as 35%(16, 17). LNG-IUS represents a newly available delivery system for EC treatment(18). It could provide local intrauterine concentrations many-fold higher than oral progestins. Some researchers used LNG-IUS solely or in combination with GnRHa and reported encouraging results(9, 19, 20). Letrozole is the third-generation AIs, which can reduce the levels of estrogen by inhibiting estrogen synthesis leading to a reduction in the receptor-mediated growth stimulated in estrogen receptor positive tumors such as EC. Combination of GnRHa and AIs has been reported as an option for preserve women’s fertility with EC and AEH(21, 22). In this study, we reported a series of patients with EC and AEH treated with GnRHa plus LNG-IUS/AIs. The preliminary results show an encouraging result a little better than or at least comparable to previous oral-progestin studies (23, 24).
In our study, over 90% patients achieved CR, 96.7% in AEH patients and 93.3% in EC patients, suggesting an encouraging result. Most AEH patients achieved CR within 6 months, but the median CR time of EC is about 3–4 months longer than AEH. 18 patients achieved CR after extension of treatment time as long as 9–15 months. Thus, we recommend that these combination regimes be administered for at least 6 months, especially for EC patients. The long-term adverse effect of GnRHa and influence on fertility by repeated curettage need to be noted. It has been documented that 2–3% of bone mass will be loss with 6 months use of GnRH analogs. And it is unclear what’s the maximal duration of therapy, whether the add-back therapy should be performed, whether the bone mineral density should be monitored, and whether calcium and bisphosphonates should be added(25). Considering that over 90% AEH patients acquired complete remission after 2 course of treatments and LNG-IUS could be used solely to treat EC(18. 19), for AEH patients who already achieved PR after 6 months, the use of LNG-IUD alone might be an option to avoid the side effect of GnRHa. But the efficacy and safety were unclear and further research is needed to accumulate experience.
In our study, patients who were obese and lose weight ༜3% have lower response and pregnancy rates, as well as higher recurrence rates, consistent with previous studies(26). Patients were unable to conceive due to obesity and PCOS, which leading to anovulation and the absence of stimulation of progestin, may also increase the risk of recurrence(27). Herein, weight control and health consulting are crucial in the whole-lifespan management of fertility-spearing treatment. GnRHa combined therapy have advantage on weight control compared with progestin therapy since we all know that weight gain was a main side effect of high-dose progestin.
Due to the data limitation, we failed to find the biomarker and the possible reason for treatment failure. MMR testing has been proposed in young women desiring fertility-sparing treatment, but the association between MMR and response is unclear (28). Some articles have proposed that the overall and recurrence-free survival was significantly lower in p53 abnormal and dMMR patient subgroups. Thus, patients with Lynch syndrome and P53 mutations may not be treated conservatively(29). The status of progesterone receptor (PR) and estrogens receptor (ER) was thought to be associated with disease regression in some research(30–32). But all patients in our study were ER and PR positive, so, we failed to analyse the relationship between IHC and of CR. As modern The Cancer Genome Atlas (TCGA)-based molecular classification system that has been validated, it might helpful to predict the response and contribute to the selection of population who suit for fertility-preserving.
Previous studies revealed a high rate of relapse, ranging from 10–88%(18, 24). In our research, about 25% women had developed recurrence with 20 months median recurrence time, consist with former articles. But some of the recurrences were diagnosed as early as 6–7 months after a CR. Another study report that recurrence occurred 3–4 months after CR which mandates the follow-up to be started early(33). The latest recurrence in our cohort took place at 7 years in our research, others also report at 13 years(34, 35). Therefore, long-term and regular follow-up is essential due to the high rate of late recurrence. Additionally, hormonal maintenance therapy is important for complete responders who do not wish to conceive immediately after completion of treatment(36). And low recurrence rate was also found in patients with pregnancy. Therefore, maintenance therapy and conception immediately were encouraged to reduce the risk of recurrence.
The pregnancy and live birth rates in our research are still somewhat suboptimal, lower than other large studies about progestin(23, 37). This might be due to endometrium atrophic decreased by repeated hysteroscopic evaluation and curettage. But the miscarriage rate at the first or second trimester are in accordance with ordinary population(38). The follow up time in our study was relatively short, if longer follow-up time were performed, high rate of relapse and live birth may be observed(39). Despite our expectations ART did not significantly improve the live birth rate, women who choosing IVF-ET had a relatively better results and some studies did report improved birth rate with ART(40, 41). Hence, once CR has been achieved, pregnancy should be carried out as soon as possible, and IVF-ET is recommended without causing significant delays.
Strengths and limitations
To the best of our knowledge, the current study included the largest number of subjects of both oncologic and reproductive results about GnRHa based treatments. The findings confirm that the combination of GnRHa with LNG-IUS/letrozole is an effective method with high rate of regression and minor side effects. But there are still some limitations. Firstly, it is a single-center retrospective study, multi-center prospective clinical trials are supposed to conducted to verify the suitability of the combination of GnRHa with LNG-IUS/letrozole use for fertility preservation. Secondly, the follow-up time of this center is limited, and long-term follow-up of these patients will also be performed to verify high pregnancy rate. Thirdly, as the modern TCGA-based molecular classification system is being introduced, it would be necessary to assess responses and recurrences in all future conservatively treated EC patients from this molecular perspective. Fourthly, long-term side-effect of GnRHa such as osteoporosis and the cardiovascular complications should be considered in future observation.