Microsatellite Instability Predicts Clinical Outcome in Radiation-Treated Endometrioid Endometrial Cancer

• Published in: International journal of radiation oncology, biology, physics Vol. 76; no. 1; pp. 9 - 13
• Main Authors: Bilbao, Cristina, Ph.D, Lara, Pedro Carlos, M.D., Ph.D, Ramírez, Raquel, Henríquez-Hernández, Luis Alberto, Ph.D, Rodríguez, Germán, Ph.D, Falcón, Orlando, M.D., Ph.D, León, Laureano, Ph.D, Perucho, Manuel, Ph.D, Díaz-Chico, Bonifacio Nicolás, Ph.D, Díaz-Chico, Juan Carlos, Ph.D
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01-01-2010
• Subjects: Adult; Age Factors; Aged; Aged, 80 and over; Biomarkers, Tumor - genetics; BODY; DISEASES; Endometrial Neoplasms - genetics; Endometrial Neoplasms - mortality; Endometrial Neoplasms - pathology; Endometrial Neoplasms - radiotherapy; Endometrial Neoplasms - surgery; Endometrioid endometrial carcinoma; Epidemiologic Methods; Female; FEMALE GENITALS; Genetic Markers; Hematology, Oncology and Palliative Medicine; Humans; Hysterectomy - methods; INSTABILITY; MATHEMATICS; MEDICINE; Microsatellite Instability; Middle Aged; MULTIVARIATE ANALYSIS; Neoplasm Recurrence, Local; NEOPLASMS; NUCLEAR MEDICINE; ORGANS; Outcome; RADIOLOGY; RADIOLOGY AND NUCLEAR MEDICINE; RADIOTHERAPY; STATISTICS; THERAPY; Treatment Outcome; UTERUS; Microsatellite instability; Radiotherapy; Endometrioid endometrial carcinoma; Outcome
• ISSN: 0360-3016; 1879-355X
• DOI: 10.1016/j.ijrobp.2009.09.035

Purpose To elucidate whether microsatellite instability (MSI) predicts clinical outcome in radiation-treated endometrioid endometrial cancer (EEC). Methods and Materials A consecutive series of 93 patients with EEC treated with extrafascial hysterectomy and postoperative radiotherapy was studied. The median clinical follow-up of patients was 138 months, with a maximum of 232 months. Five quasimonomorphic mononucleotide markers (BAT-25, BAT-26, NR21, NR24, and NR27) were used for MSI classification. Results Twenty-five patients (22%) were classified as MSI. Both in the whole series and in early stages (I and II), univariate analysis showed a significant association between MSI and poorer 10-year local disease-free survival, disease-free survival, and cancer-specific survival. In multivariate analysis, MSI was excluded from the final regression model in the whole series, but in early stages MSI provided additional significant predictive information independent of traditional prognostic and predictive factors (age, stage, grade, and vascular invasion) for disease-free survival (hazard ratio [HR] 3.25, 95% confidence interval [CI] 1.01–10.49; p = 0.048) and cancer-specific survival (HR 4.20, 95% CI 1.23–14.35; p = 0.022) and was marginally significant for local disease-free survival (HR 3.54, 95% CI 0.93–13.46; p = 0.064). Conclusions These results suggest that MSI may predict radiotherapy response in early-stage EEC.