Effect on survival of longer intervals between confirmed diagnosis and treatment initiation among low-income women with breast cancer

Abstract

Purpose: To determine the impact of longer periods between biopsy-confirmed breast cancer diagnosis and the initiation of treatment (Dx2Tx) on survival.

Patients and methods: This study was a noninterventional, retrospective analysis of adult female North Carolina Medicaid enrollees diagnosed with breast cancer from January 1, 2000, through December, 31, 2002, in the linked North Carolina Central Cancer Registry-Medicaid Claims database. Follow-up data were available through July 31, 2006. Cox proportional hazards regression models were constructed to evaluate the impact on survival of delaying treatment ≥ 60 days after a confirmed diagnosis of breast cancer.

Results: The study cohort consisted of 1,786 low-income, adult women with a mean age of 61.6 years. A large proportion of the patients (44.3%) were racial minorities. Median time from biopsy-confirmed diagnosis to treatment initiation was 22 days. Adjusted Cox proportional hazards regression showed that although Dx2Tx length did not affect survival among those diagnosed at early stage, among late-stage patients, intervals between diagnosis and first treatment ≥ 60 days were associated with significantly worse overall survival (hazard ratio [HR], 1.66; 95% CI, 1.00 to 2.77; P = .05) and breast cancer-specific survival (HR, 1.85; 95% CI, 1.04 to 3.27; P = .04).

Conclusion: One in 10 women waited ≥ 60 days to initiate treatment after a diagnosis of breast cancer. Waiting ≥ 60 days to initiate treatment was associated with a significant 66% and 85% increased risk of overall and breast cancer-related death, respectively, among late-stage patients. Interventions designed to increase the timeliness of receiving breast cancer treatments should target late-stage patients, and clinicians should strive to promptly triage and initiate treatment for patients diagnosed at late stage.

Fig 1.

Study inclusion and exclusion criteria. NC, North Carolina.

Fig 2.

(A) Crude and (B) adjusted overall survival curves for late-stage patients (time from biopsy-confirmed diagnosis to the initiation of treatment ≥ 60 days v 0 to 59 days; n = 721). HR, hazard ratio.

Fig 3.

(A) Crude and (B) adjusted breast cancer–specific survival curves for late-stage patients (time from biopsy-confirmed diagnosis to the initiation of treatment ≥ 60 days v 0 to 59 days; n = 721). HR, hazard ratio.

Fig 4.

Sensitivity analysis of fully adjusted overall and breast cancer–specific survival for time from biopsy-confirmed diagnosis to the initiation of treatment ≥ 60 days versus 0 to 59 days by stage at diagnosis subgroup. Models for the in situ–only subgroup are not presented because there were too few events to build a valid model. All model results are adjusted for age, race, marital status, year of diagnosis, metropolitan status, and health professional shortage area status of a patient's county of residence at diagnosis, stage at diagnosis (where > one stage is included), tumor size, hormone receptor status, Charlson comorbidity index, disability status, whether or not the patient lived in home health care or assisted living care in the year before diagnosis, whether or not the patient had any claims for consultations/procedures for biopsies or medical imaging or for hospitalizations or emergency department visits between diagnosis and treatment, type of surgery received, and whether or not chemotherapy, radiation therapy, or hormonal therapy was administered. RR, relative risk.