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The association between common breast cancer therapies and recurrences and second primary breast cancers in older women is unclear, although older women are less likely to receive common therapies.Women aged ≥65 years who were diagnosed with stage I or II breast cancer and who underwent mastectomy or breast‐conserving surgery (BCS) from 1990 to 1994 were identified from automated data from 6 healthcare systems and then were followed for 10 years or until breast cancer recurrence, disenrollment, or death. Trained abstractors reviewed medical records to obtain recurrence, tumor, treatment and demographic data. The authors used proportional hazards models to examine predictors of recurrent and second primary breast cancers adjusted for demographic and tumor factors.Of 1837 eligible women, 34% were ages 65 to 69 years, 46% were ages 70 to 79 years, and 20% were aged ≥80 years. In multivariable models that used mastectomy as the reference group, BCS without radiation therapy was associated with an increased risk of any recurrent and second primary breast cancer (hazard ratio [HR], 1.6; 95% confidence interval [CI], 1.1–2.3), particularly with the subgroup of women with local and regional recurrence (HR, 3.5; 95% CI, 2.0–6.0). Tamoxifen use for <1 year versus ≥5 years exhibited a borderline association with any recurrent or second primary breast cancer (HR, 1.9; 95% CI, 0.9–4.2).Radiation therapy after BCS and 5 years of tamoxifen use were beneficial in reducing recurrences and second primary breast cancers in older women, regardless of their age or comorbidity burden. Cancer 2007. © 2007 American Cancer Society. [ABSTRACT FROM AUTHOR]

The quality of medical record abstracts is often characterized in a reliability substudy. These results usually indicate agreement, but not the extent to which lack of agreement affects associations observed in the complete data. In this study, medical records were reviewed and abstracted for patients diagnosed with stage I or stage II breast cancer between 1990 and 1994 at one of six US Cancer Research Network sites. For a subsample, interrater reliability data were available. The authors calculated conventional hazard ratios and 95% confidence intervals for the association of demographic, tumor, and treatment characteristics with recurrence rate. These conventional estimates of effect were compared with three sets of estimates and 95% simulation intervals that took account of the uncertainty assessed by lack of agreement in the reliability substudy. The rate of recurrence was associated with increasing cancer stage and with treatment modality but not with demographic characteristics. The hazard ratios and simulation intervals that took account of the reliability data showed that the simulation interval grew wider as the sources of uncertainty taken into account grew more complete, but the associations expected a priori remained readily apparent. While many investigators use reliability data only as a metric for data quality, a more thorough approach can also quantitatively depict the uncertainty in the observed associations. [ABSTRACT FROM AUTHOR]