Letrozole as Maintenance Therapy for Post-surgical Endometrial Cancer Patients With NSMP

Prior treatment

• Patients require no adjuvant therapy after surgery;
• Received other adjuvant therapy within 6 months before surgery: including neoadjuvant therapy, hormone therapy, targeted therapy, immunotherapy and biotherapy, etc;

Other illness

• Recurrent endometrial cancers;
• Patients with other malignant tumors;
• History of vital organ transplantation;
• History of immune disease and need to take immunosuppressor;
• Uncontrolled psychiatric illness or other situations that would limit compliance with study requirements;
• History of drug abuse;

Other

• Endometrial stromal tumor;
• Patients with low prognostic risk according to post-operative clinical pathological assessment ( Stage IA endometrioid + low-grade* +LVSI negative or focal);
• Negative expression in estrogen receptor or progesterone receptor according to post-operative Immunohistochemistry;
• Patients with contraindications for letrozole;
• Participated in other clinical trials;
• No ability or intention to receive letrozole maintenance/sign the consent/obey the study requirements.

• Older than 18 years old;
• Initial diagnosed with stage I-IV(FIGO2009) endometrial epithelial cancer, regardless of pathological types;
• Surgery must have included a hysterectomy, bilateral salpingo-oophorectomy and sentinel node biopsy; pelvic lymph node sampling and para-aortic lymph node sampling are optional;
• Life expectancy of 2 or more years.
• Confirmed NSMP with intermediate or higher prognostic risk according to post-operative clinical pathological assessment and molecular classification;
  • Intermediate prognostic risk group:
  • Stage lB endometrioid + Iow-grade* + LVSI negative or focal
  • Stage IA endometrioid + high-grade*+ LVSI negative or focal
  • Stage IA non-endometrioid (serous, clear cell, undifferentiated carcinoma, carcinosarcoma, mixed) without myometrial invasion
  • High-intermediate prognostic risk group:
  • Stage I endometrioid + substantial LVSI, regardless of grade and depth of invasion
  • Stage lB endometrioid high-grade*, regardless of LVSI status
  • Stage II
  • High prognostic risk group:
  • Stage Ill-IVA with no residual disease
  • Stage I-IVA non-endometrioid (serous, clear cell, undifferentiated carcinoma, carcinosarcoma, mixed) with myometrial invasion, and with no residual disease
  • Advanced Metastatic:
  • Stage III-IVA with residual disease
  • Stage IVB Low grade: G1-2; High grade:G3;
• Received conventional adjuvant therapy after surgery according to the latest version of NCCN or ESGO/ESTRO/ESP guidelines;
• Patients with residual tumor after surgery (any single site) must have achieved complete response or partial response after post-operative adjuvant therapy;
• Expected start of letrozole maintenance within 3 months after adjuvant therapy;
• Adequate organ function as defined by the following criteria:
  • White blood cell (WBC) ≥ 3000/μL or Absolute neutrophil count (ANC) ≥1500/μL
  • Platelets ≥100,000/μL
  • Serum Aspartate transaminase (AST) and/or serum alanine transaminase (ALT) ≤ 2 times upper limit of normal (ULN)
  • Serum creatinine ≤2 times ULN
• Karnofsky score ≥60;
• Eastern Cooperative Oncology Group (ECOG) Performance status ≤2;
• Ability to take anti-thyroid drugs, calcium, vitamin D or bisphosphonates together.