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To identify factors associated with delayed radiotherapy (RT) in older women with early stage breast cancer.
We studied 541 women ages 65+ diagnosed with early stage breast cancer from 1990–1994 at five integrated healthcare delivery systems and treated with breast conserving surgery and RT, but not chemotherapy. We examined whether demographic, tumor, or treatment characteristics were associated with RT delays of >8 weeks post-surgery using chi-square tests and multivariable logistic regression.
Seventy-six women (14%) had delayed RT, with a median delay of 14 weeks. Non-white and Hispanic women were much more likely than White women to have delayed RT (OR=3.3, 95%CI: 1.7, 10) in multivariable analyses that controlled for demographic and clinical variables.
Of women receiving BCS and radiation in this cohort, 14% experienced delayed RT, even though they had insurance and access to care in integrated delivery systems. Women receiving delayed care were more likely to be non-White and Hispanic. Timely RT should be facilitated through physician and patient education, navigation, and notification programs to improve quality of care. Future research should examine modifiable barriers to RT timeliness and whether delays impact long-term outcomes.
Breast cancer, diagnosed in 180,000 women in the United States in 2008 (1), is usually treated with mastectomy or breast-conserving surgery (BCS) with or without radiotherapy (RT)(2) Treatment characteristics vary by race/ethnicity, socioeconomic status, geographic region, healthcare access, and insurance status (3–8). Quality of care, including timing and completeness of RT and chemotherapy, can affect recurrence and survival rates (9–13). The start of RT is time sensitive, yet many factors can affect whether a patient experiences a delayed start. If she has positive nodes, she may be more likely to have longer discussions about treatment options because more options are available (2). As breast cancer treatment requires extensive coordination of care across multiple providers and specialties, patients may experience difficulties navigating the healthcare system (14). Typical treatment starts with surgery and lymph node assessment, followed by recovery time after surgery, subsequent RT to the whole breast for 5–6 weeks, and a 1-week RT boost to the tumor bed (2). Positive lymph nodes are an indication for chemotherapy prior to or concurrent with RT (2).
There is conflicting evidence regarding the optimal timing of RT following BCS (11;15–19). One study suggests that RT delay does not negatively affect breast-cancer-related health outcomes (19), but most have found a negative impact (11;15–18). A systematic review concluded that RT delay was associated with higher rates of local recurrence (17). RT delay may also be associated with psychological distress and anxiety, which can negatively impact the care process and outcomes (20).
This study assesses patient-level predictors of delayed RT in an insured population of older women with early stage breast cancer treated in integrated healthcare delivery systems, a group that has not been studied for its timeliness in receiving RT.
This study is nested in the Breast Cancer Treatment Effectiveness in Older Women (BOW) Study cohort (21). We included 541 women ages 65+ diagnosed with unilateral, early-stage breast cancer (American Joint Commission on Cancer [AJCC](22) Stages I or II) enrolled in five integrated delivery systems in the Cancer Research Network, a collaborative group of research programs, enrolled populations, and data systems of 14 health systems nationwide (23). Women diagnosed from 1990–1994 were followed for 10 years. All subjects in this nested cohort received BCS with a full course of whole breast RT, but no chemotherapy. Subjects from the original cohort receiving BCS without RT (23%) or mastectomy (53%) were excluded (21). We restricted the sample to women not receiving chemotherapy to eliminate variations in RT timing related to chemotherapy sequencing. We used automated administrative databases, medical record review, and tumor registries to ascertain age, race/ethnicity, Charlson Comorbidity Index (24), lymph node status, tumor size, histology, estrogen or progesterone receptor (ER, PR) status, and any use of tamoxifen. To calculate the Charlson Comorbidity Index, information on comorbid conditions was collected from medical records for all health care services for one year prior to diagnosis. This index includes 18 conditions weighted to predict mortality. We excluded cancer diagnoses from the index and categorized the remaining score as 0, 1, or 2+. Because others have shown that an 8-week delay can impact health outcomes, we defined RT delay as starting RT >8 weeks following BCS, based on medical record data (11;17). All research was conducted following approval from local institutional review boards (IRBs) and in accordance with the ethical standards of the local IRBs.
We calculated the percentage of women with delayed RT and the percentage with timely RT by demographic and clinical characteristics. We used chi-squared tests and fit multivariable logistic regression models to identify factors associated with delayed RT; we controlled for integrated delivery system site.
The sample included 541 women, of whom 76 (14%) had a delay of more than 8 weeks (Figure 1). Among women with RT delayed >8 weeks, the median delay was 14 weeks, and 21 subjects (4%) had delays >12 weeks. More than two-thirds of the sample was <75 years, and few (3.3%) scored >1 on the Charlson Comorbidity Index. Almost 7% were ER-/PR-, and 13% of subjects had positive nodes (Table 1). In multivariable analyses (Table 2), women of non-White race or Hispanic ethnicity had significantly higher odds of delayed RT (OR=3.3, 95%CI: 1.7, 10). We had limited precision in general, as indicated by some wide confidence intervals (e.g., tumor size >2cm (OR=1.9, 95% CI 0.9, 4.1) and ER-/PR- status (OR=1.8, 95%CI 0.7, 4.9)).
In this fully-insured population of older women with breast cancer who had access to integrated delivery systems, about 1 in 7 women experienced delayed RT following BCS, a rate similar to other studies (11;17). Surprisingly, in this population, the proportion with RT delays >8 weeks was about the same as that found in a fee-for-service Medicare population (14% vs. 16%, respectively)(11). One might expect better coordinated, and therefore less delayed, care in integrated healthcare delivery systems, yet such delays >8 weeks may be due to healthcare access issues such as transportation problems, language concordance or communication issues, or limited patient knowledge about the importance of timely RT, all barriers that are not mediated by insurance status. Alternatively delays may be caused by poor care coordination by clinicians and the healthcare system or patient-related barriers, concerns, or anxiety regarding decision-making and treatment itself (20;25;26).
The only predictor of delayed RT was non-White and Hispanic race/ethnicity, consistent with previous research (11;18). Indeed, delayed RT, which may represent uncoordinated care among other possible factors, was not affected significantly by other included clinical or demographic factors. Whether these delays in turn affect mortality for patients in integrated delivery systems could not be shown due to statistical power limitations.
All eligible women were included in our study population, and we had no loss to follow-up in the treatment period. This design advantage substantially limits the potential for selection bias. Another strength of this study is that all subjects in the cohort had equal access to complete treatment by having access to care in an integrated healthcare delivery system. In addition to sociodemographic information (beyond age), we had important information about the tumors themselves that helped explain treatment receipt and reduced confounding in our analyses. Nonetheless, we did not have information on characteristics such as patient educational attainment, income, transportation availability, radiation oncologist availability, language barriers, or preferences for care; doctor-patient communication; or healthcare system programs, such as care coordination, which may be greater barriers to or facilitators of care for older women diagnosed with breast cancer (14;25). We do know, however, that non-White women and those of Hispanic ethnicity are more likely to be of lower socioeconomic status (27), however, and therefore these factors may directly or indirectly influence care-seeking behavior and receipt. All subjects had Medicare coverage in these healthcare systems with the same benefits for RT and Medicare paying for RT in inpatient, outpatient, and freestanding clinics. Outpatient RT requires a set copayment, which was usually lower than fee-for-service copayments, thereby reducing barriers to care even more. It is unlikely that coverage levels affected timeliness of RT.
We have shown that healthcare access, as reflected by a patient’s membership in an integrated healthcare delivery system, does not in itself ensure timely therapy. Rates of RT delay were similar between integrated delivery systems and the fee-for-service sector (11) and appear to be affected by race/ethnicity. Healthcare delivery systems and providers should consider targeting care coordination efforts to traditionally underserved patients to improve timeliness of RT.
This study identified factors associated with delayed radiotherapy for breast cancer in integrated healthcare delivery systems; 14% experienced delayed RT, even though they had insurance.
This study identified factors associated with delayed radiotherapy for breast cancer in integrated healthcare delivery systems; 14% experienced delayed RT, even though they had insurance and access to care.
Funded by the National Cancer Institute (R01 CA093772, R Silliman, PI) and in part by the American Cancer Society (MRSGT-04-002-01-CPHPS, HT Gold, PI).
Heather Taffet Gold, Department of Public Health, Weill Cornell Medical College.
Soe Soe Thwin, Boston University Medical Center.
Diana SM Buist, Group Health Center for Health Studies.
Terry S Field, Meyers Primary Care Institute, University of Massachusetts, Fallon Clinic, Fallon Community Health Plan.
Feifei Wei, HealthPartners Research Foundation.
Marianne Ulcickas Yood, Henry Ford Health System and Yale University School of Medicine.
Timothy L. Lash, Boston University Medical Center.
Virginia Quinn, Kaiser Permanente-Southern California.
Ann M Geiger, Wake Forest University School of Medicine.
Rebecca A Silliman, Boston University Medical Center.