title: Patterns of chemotherapy, toxicity, and short-term outcomes for older women receiving adjuvant trastuzumab-based therapy.
abstract: Limited data are available regarding patterns of chemotherapy receipt and treatment-related toxicities for older women receiving adjuvant trastuzumab-based therapy. We used surveillance, epidemiology and end results (SEER)-Medicare data to identify patients ≥66 years with stage I-III breast cancer treated during 2005-2009, who received trastuzumab-based therapy. We examined patterns of chemotherapy receipt, and using multivariable logistic regression, we examined associations of age and comorbidity with non-standard chemotherapy. In propensity-weighted cohorts of women receiving standard and non-standard trastuzumab-based therapy, we also examined rates of (1) hospital events during the first 6 months of chemotherapy and (2) short-term survival. Among 2,106 women, 29.7 % were aged ≥76 and 66 % had a comorbidity score = 0. Overall, 31.3 % of women received non-standard chemotherapy. Compared to patients aged 66-70, older patients more often received non-standard chemotherapy [adjusted odds ratio (OR) = 4.1, 95 % confidence interval (CI) = 3.40-4.92 (ages 76-80); OR = 15.3, 95 %CI = 9.92-23.67 (age ≥ 80)]. However, comorbidity was not associated with receipt of non-standard chemotherapy. After propensity score adjustment, hospitalizations were more frequent in the standard (vs. non-standard) group (adjusted OR = 1.7, 95 % CI = 1.29-2.24). With a median follow-up of 2.8 years, 276 deaths occurred; the adjusted hazard ratio (HR) for death was lower in standard versus non-standard treated women (HR = 0.69, 95 % CI = 0.52-0.91). Among a population-based cohort of older women receiving trastuzumab, nearly one-third received non-standard chemotherapy, with the highest rates among the oldest women. Non-standard chemotherapy was associated with fewer toxicity-related hospitalizations but worse survival. Further exploration of treatment toxicities and outcomes for older women with HER2-positive breast cancer is warranted.
authors.affiliation: Department of Medical Oncology, Dana Farber Cancer Institute, 450 Brookline Avenue, Boston, MA, 02215, USA, rafreedman@partners.org.
authors.forename: Rachel A
authors.initials: RA
authors.lastname: Freedman
authors.forename: Ines
authors.initials: I
authors.lastname: Vaz-Luis
authors.forename: William T
authors.initials: WT
authors.lastname: Barry
authors.forename: Huichuan
authors.initials: H
authors.lastname: Lii
authors.forename: Nancy U
authors.initials: NU
authors.lastname: Lin
authors.forename: Eric P
authors.initials: EP
authors.lastname: Winer
authors.forename: Nancy L
authors.initials: NL
authors.lastname: Keating
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D061067:Antibodies, Monoclonal, Humanized / Q000009:adverse effects / Q000627:therapeutic use*; D000970:Antineoplastic Agents / Q000009:adverse effects / Q000627:therapeutic use; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use; D001943:Breast Neoplasms / Q000188:drug therapy* / Q000453:epidemiology / Q000401:mortality / Q000601:surgery; D017024:Chemotherapy, Adjuvant; D015897:Comorbidity; D005260:Female; D006801:Humans; D006278:Medicare; D018426:SEER Program; D015996:Survival Rate; D000068878:Trastuzumab; D016896:Treatment Outcome; D014481:United States
chemical_list: D061067:Antibodies, Monoclonal, Humanized; D000970:Antineoplastic Agents; D000068878:Trastuzumab