摘要
Background:Invasive micropapillary carcinoma(IMPC)is an uncommon subtype of breast cancer.Previous studies of this subtype demonstrated a higher propensity for lymph node metastases as compared with invasive ductal carci-noma(IDC).The purpose of the present study was to determine the clinical characteristics,outcomes,and propensity for lymph node metastasis of patients with IMPC of the breast recorded in the National Cancer Database(NCDB).Methods:Records of patients with IMPC diagnosed between 2004 and 2014 were retrieved from the NCDB.Log-rank test was performed to evaluate associations of clinical characteristics with overall survival(OS).Cox proportional hazards model was used to determine variables associated with OS.Results:Overall,2660 patients with IMPC met the selection criteria;the 5-year OS rate was 87.5%and 24.9%of patients had nodal involvement at presentation.Patients with≥4 positive lymph nodes had shorter OS than node-negative patients,whereas patients with 1-3 positive nodes had similar OS to node-negative patients.Age<65 years,receipt of radiotherapy,and estrogen receptor positivity were also associated with prolonged OS.The benefit of radiotherapy was limited to IMPC patients undergoing lumpectomy;there was no benefit for the patients undergoing mastectomy(regardless of nodal positivity/negativity).Conclusions:Favorable prognostic factors of IMPC patients included age<65 years,<4 positive lymph nodes,receipt of radiotherapy,and estrogen receptor positivity.The results presented herein suggest a survival benefit asso-ciated with radiotherapy in IMPC treatment,though this may be limited to the patients treated with lumpectomy.
