PD-1 Inhibitor Combined With Progesterone Treatment in FST for Patients With MMRd Endometrial Cancer

Endometrial cancer (EC) is a prevalent gynecological cancer with an escalating global incidence. The standard treatment for endometrial cancer is total hysterectomy and bilateral salpingo-oophorectomy. However, given the rising incidence of endometrial cancer in younger individuals and the the delay in the age of human reproduction, the conservation of endometrial cancer has garnered heightened attention. Clinical practice has demonstrated that high-dose progesterone can reverse the lesioned endometrium, thereby providing a rationale for the conservative treatment of early-stage endometrial cancer.

PD-1 inhibitor has been utilized as a salvage treatment in many cancers including ovarian cancer, cervical cancer, lung cancer, gastric cancer and endometrial cancer. As endometrial cancer showed MMRd rates, it is assumed to be highly responsive to PD-1 inhibitor treatment. Previous literature has reported that the efficacy of progesterone therapy is limited in patients with a MMRd status.Here we want to investigate the feasibility of PD-1 inhibitor combined with progesterone in early stage endometrial cancer patients who want to preserve fertility.

Inclusion criteria

• Be between the ages of 18-45 years old;
• Stage IA (FIGO 2009) ;
• Confirmed diagnosis of endometrial adenocarcinoma G1-G2 based upon D&C or hysteroscopy;
• Molecular classification of MMRd, determined by immunohistochemical (IHC) for MMR proteins and by the second generation sequencing (NGS) or microsatellite polymerase chain reaction (PCR);
• With a strong desire for fertility preservation;
• Sign the informed consent.

Exclusion criteria

• Stage IB(FIGO 2009) and above；
• Tumour differentiation of G3 or non-endometrioid adenocarcinoma；
• Complicated with any other malignancy；
• Contraindicated to conservative treatment or the use of pharmaceuticals.
• Contraindications to pregnancy, or judged by the researcher to be unfit for pregnancy or delivery.