Date of Award

January 2013

Document Type

Open Access Thesis

Degree Name

Medical Doctor (MD)

Department

Medicine

First Advisor

Cary Gross

Subject Area(s)

Medicine

Abstract

PART 1:

BACKGROUND: Because the benefits of adjuvant radiation therapy (RT) for breast cancer decrease with increasing age, the use of expensive and unproven RT modalities such as brachytherapy in the treatment of older women has been questioned. In particular, patients and policy makers may be concerned that for-profit hospitals might be more likely to use therapies with higher reimbursements. Among both younger and older Medicare beneficiaries with breast cancer, we examined whether hospital ownership status is associated with use of adjuvant brachytherapy.

METHODS: We conducted a retrospective study of female Medicare beneficiaries aged 66-94 years old receiving breast-conserving surgery for invasive breast cancer in 2008 and 2009. We assessed the relationship between hospital ownership and receipt of brachytherapy, as well as overall RT (i.e. brachytherapy or whole breast irradiation (WBI)) using hierarchical generalized linear models.

RESULTS: The sample consisted of 35,118 women, 8.0% of whom had undergone surgery at for-profit hospitals. Among patients who received RT, those who underwent surgery at for-profit hospitals were significantly more likely to receive brachytherapy (20.2%) than patients treated at not-for-profit hospitals (15.2%; Odds Ratio (OR) for profit vs. not-for profit: 1.50, 95% CI: 1.23-1.84). Among women 66-79 years old, there was no relation between hospital profit status and overall RT use. However, among women age 80-94 years old, receipt of surgery at a for-profit hospital was significantly associated with higher overall RT use (1.22; 1.03-1.45) and brachytherapy use (1.66; 1.18-2.34), but not WBI use (1.14; 0.96-1.36)

CONCLUSIONS: Medicare beneficiaries undergoing breast-conserving surgery at for-profit hospitals were more likely to receive brachytherapy, a newer, less proven, and more expensive technology. Among the oldest women, who are least likely to benefit from RT, care at a for-profit hospital was associated with higher overall RT use, which was explained by higher utilization of brachytherapy in this subgroup

PART 2:

PURPOSE: The use and limited benefit of radiation therapy in the clinical care of older women with favorable risk breast cancer have raised concerns about overuse, expenditure, and cost-effectiveness. Moreover, newer radiation therapy modalities such as intensity modulated radiation therapy (IMRT) and brachytherapy are diffusing into the clinical practice despite their increased costs and uncertain clinical benefit. We used Medicare data to: (1) estimate incremental cost-effectiveness ratios (ICERs) of external beam radiation therapy (EBRT) compared to no radiation; (2) incorporate age and comorbidity into cost-effectiveness estimates of EBRT; (3) evaluate the cost-effectiveness of newer radiation modalities.

METHODS: Using the Surveillance, Epidemiology, and End Results-Medicare database, we identified women who fulfilled the Cancer and Leukemia Group B C9343 trial criteria (>70 years of age, tumor size ≤2cm, estrogen-receptor positive status, node negative) and in whom the use of radiation can be safely omitted. We estimated the annual recurrence, annual metastasis and determined 10-year survival rates according to receipt of EBRT. We determined cancer-related costs to Medicare from a payer perspective. Assuming that all radiation modalities have equivalent effectiveness, we used a Markov decision model to calculate ICERs for each modality compared to no radiation therapy over a 10-year time horizon. We determined the ICERs for various radiation modalities by age and comorbidity status.

RESULTS:The median incremental radiation-related cost associated with EBRT compared to no radiation was $10,308. The cost-effectiveness ratio of EBRT compared to no radiation for the full study sample was $43,015/QALY, and increased with increasing age, ranging from $36,675 (ages 70-74) to $51,375 (ages 80-94) per QALY. The ICER for EBRT among the oldest women with the most comorbidities reached $343,333/QALY. The number needed to treat with radiation to prevent one recurrence was 125. The median incremental cost was $19,254 for IMRT and $18,249 for brachytherapy. Newer treatments would have to be at least 30% more effective to be cost-effective.

CONCLUSIONS: EBRT is cost-effective for a many older women with early stage breast cancer, but substantially less cost-effective for older women with multiple comorbidities. Newer radiation modalities would have to be less costly or substantially more effective in improving quality of life to be cost-effective

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