title: Older Patients With Early-stage Breast Cancer: Adjuvant Radiation Therapy and Predictive Factors for Cancer-related Death.
abstract: OBJECTIVE
  Studies have shown that older women are undertreated for breast cancer. Few data are available on cancer-related death in elderly women aged 70 years and older with pathologic stage T1a-b N0 breast cancer and the impact of prognostic factors on cancer-related death.
  
  
  METHODS
  The Surveillance, Epidemiology, and End Results (SEER) database was queried for women aged 70 years or above diagnosed with pT1a or pT1b, N0 breast cancer who underwent breast conservation surgery from 1999 to 2003. The Kaplan-Meier survival analysis was performed to evaluate breast cause-specific survival (CSS) and overall survival (OS), and the log-rank test was employed to compare CSS/OS between different groups of interest. Multivariable analysis (MVA), using Cox proportional hazards regression analysis, was performed to evaluate the independent effect of age, race, stage, grade, ER status, and radiation treatment on CSS. Adjusted hazard ratios were calculated from the MVA and reflect the increased risk of breast cancer death. Competing-risks survival regression was also performed to adjust the univariate and multivariable CSS hazard ratios for the competing event of death due to causes other than breast cancer.
  
  
  RESULTS
  Patients aged 85 and above had a greater risk of breast cancer death compared with patients aged 70 to 74 years (referent category) (adjusted hazard ratio [HRs]=1.98). Race had no effect on CSS. Patients with stage T1bN0 breast cancer had a greater risk of breast cancer death compared with stage T1aN0 patients (adjusted HR=1.35; P=0.09). ER negative patients had a greater risk of breast cancer death compared with ER positive patients (adjusted HR=1.59; P<0.017). Patients with higher grade tumors had a greater risk of breast cancer death compared with patients with grade 1 tumors (referent category) (adjusted HRs=1.69 and 2.96 for grade 2 and 3, respectively). Patients who underwent radiation therapy had a lower risk of breast cancer death compared with patients who did not (adjusted HR=0.55; P<0.0001).
  
  
  CONCLUSIONS
  Older patients with higher grade, pT1b, ER-negative breast cancer had increased risk of breast cancer-related death. Adjuvant radiation therapy may provide a CSS benefit in this elderly patient population.
authors.affiliation: *Department of Radiation Oncology, New York Presbyterian-Hospital/Weill Cornell Medical College †Division of Biostatistics and Epidemiology, Department of Public Health, Weill Cornell Medical College, New York, NY.
authors.forename: Himanshu
authors.initials: H
authors.lastname: Nagar
authors.forename: Weisi
authors.initials: W
authors.lastname: Yan
authors.forename: Paul
authors.initials: P
authors.lastname: Christos
authors.forename: K S Clifford
authors.initials: KSC
authors.lastname: Chao
authors.forename: Dattatreyudu
authors.initials: D
authors.lastname: Nori
authors.forename: Akkamma
authors.initials: A
authors.lastname: Ravi
mesh_terms: D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D001943:Breast Neoplasms / Q000737:chemistry / Q000401:mortality* / Q000473:pathology / Q000628:therapy*; D005260:Female; D006801:Humans; D053208:Kaplan-Meier Estimate; D015412:Mastectomy, Segmental; D060787:Neoplasm Grading; D009367:Neoplasm Staging; D016016:Proportional Hazards Models; D018714:Radiotherapy, Adjuvant; D011960:Receptors, Estrogen / Q000032:analysis; D018426:SEER Program; D015996:Survival Rate
chemical_list: D011960:Receptors, Estrogen