Cost of palliative radiation to the bone for patients with bone metastases secondary to breast or prostate cancer

Bone metastasis, the most common cause of cancer-related pain, [1‐3] occurs in up to 90% of patients with advanced breast or prostate cancer [1, 2, 4, 5]. Median survival times for patients with breast and prostate cancer after diagnosis of bone metastasis range from 24 to 36 months [6‐8]. Care of bone metastases is directed at decreasing skeletal complications, delaying or relieving pain, avoiding toxicity, and maintaining functional independence [2, 9, 10]. Treatment for the care of bone metastases can include surgery, radiotherapy, analgesics, anti-resorptive agents (e.g., denosumab, bisphosphonates), and radiopharmaceuticals. The prevailing treatment modality for bone metastases is radiation therapy, which is recommended by the National Comprehensive Cancer Network (NCCN) clinical oncology practice guidelines for use after or in conjunction with denosumab or bisphosphonates in treatment of patients with breast or prostate cancer [11, 12]. Radiation therapy has been demonstrated to be effective in pain relief and in reducing pathological fractures and spinal cord compression, which may lead to functional improvements [2, 13].

Radiation treatment to bone in patients with bone metastases contributes significantly to the overall burden of cancer therapy [14, 15] and the socioeconomic impact is expected to increase with the aging of the populations of developed countries [16]. Of note, approximately half of the Medicare costs for patients with cancer are incurred during the last 60 days of life [15]. While it is one of the most common treatment modalities, relatively little is known about the economic burden of palliative radiation therapy for bone metastases. Certain economic modeling studies suggest that single-fraction radiation therapy is more cost effective than pain medication, chemotherapy, and multifraction radiation therapy [17‐20]. However, these studies primarily used data from clinical trials or the medical literature with estimated charges and costs based on the literature, expert opinion, or patient surveys; as estimates, their results may not reliably reflect the actual cost of radiation therapy as used in clinical practice. The intent of the study reported herein was to estimate and establish, based on current clinical practice data, the actual costs (paid amounts, rather than charged or billed) of palliative radiation episodes of care (REOCs) for bone metastases secondary to breast or prostate cancer. Total radiation costs, radiation direct costs, and the costs of radiation-related visits and procedures associated with the REOC are reported.

Increasing limitations on healthcare resources and the recognition that treatment of bone metastases contributes significantly to the socioeconomic burden of cancer have led to calls to evaluate and better understand costs associated with treatment [14‐16]. This study quantified the recorded, actual, and paid costs of palliative radiation therapy for bone metastases secondary to breast or prostate cancer. Results from the analysis demonstrate that the total cost of radiation therapy for bone metastases was substantial. Mean total radiation costs (i.e., direct radiation cost + cost of radiation-related procedures and visits excluding actual radiation) per REOC were $7457 for breast cancer patients and $7553 for prostate cancer patients. Radiation direct costs accounted for the majority of total radiation costs. Total radiation costs did not differ materially between breast cancer and prostate cancer. Likewise, total radiation costs did not differ materially as a function of how unpopulated payment records were accounted for (i.e., records with unpopulated costs excluded from the main analysis; patients with unpopulated cost records excluded from the sensitivity analysis).

Palliative radiation practices including length of treatment, dose, radiation schedule, fractions by REOC, and frequency of fractions, appear to be similar for the treatment of patients with breast or prostate cancer. Likewise, the bone sites radiated during a REOC were also similar for the treatment of patients with breast or prostate cancer. The most commonly irradiated bone sites for both cancer types were the spine and the hip, and the least common was the humerus; most likely reflecting the variations in incidence, surrounding normal-tissue tolerance, extent of metastatic lesion(s), and other factors.

In addition to quantifying the costs of radiation therapy as used in current clinical practice, the results of this study sheds light on US practice patterns of radiation to bone in patients with bone metastases. Current guidelines indicate that radiotherapy is a successful and efficient method by which to palliate pain and/or prevent the morbidity of bone metastases [21]. For the majority of patients with breast or prostate cancer, the median number of fractions per REOC was 10; a result reflecting common use of multifraction therapy. Clinical evidence, including that from three large, randomized trials of single-fraction therapy (8 Gy) vs. multifraction therapy (20 to 30 Gy), demonstrates that single-fraction therapy may be as effective as multifraction therapy for the treatment of bone metastases [21‐24]. Although single-fraction therapy may be as clinically effective, more convenient for the patient, and less expensive than multifraction therapy, single-fraction therapy has not currently been accepted as standard practice in the US [25, 26]. A contributing factor may be the durability of the pain response as multifraction regimens (10 fractions vs. 1 fraction) have been associated with less re-treatment. This point is supported by the median and mean numbers of fractions observed per REOC for patients with breast or prostate cancer in the current study, which indicates that the use of multi-fraction schedules in the management of patients with advanced breast or prostate cancer and bone metastases is common, and is likely associated with a substantial patient burden.

Strengths of this study include its geographical diversity (data from 98 radiation cancer treatment centers in 16 US states), reflection of recent practice patterns (study period from 1 July 2008 to 31 December 2009), and “real-world” reflections (data based on electronic medical records from freestanding and hospital-based cancer treatment centers). However, the results reflect centers in 16 states and it is unknown if other centers, particularly in the other 34 states, would present similar findings. Limitations, typical of retrospective, claims-based studies, include the potential for coding errors and underreported or missing information on historical radiation treatment. In addition, the limitation of incomplete patient records, a typical shortcoming of claims-based studies, was addressed in the current study by undertaking a sensitivity analysis where patients were excluded if they had any unpopulated or absent cost records. The results on healthcare resource use and the cost data were similar and followed a consistent pattern across analysis methods, suggesting that the occurrence of incomplete payment records did not systematically affect the results. The results are specific to patients with bone metastases treated with radiation therapy, and the cost for those not treated with radiation was not studied. Lastly, it is important to note that these results describe an ‘average’ patient, and we know as clinicians and researchers that patients are individuals that follow a broad range of patterns.

Future research to examine concurrence or variations of these findings within other states will be beneficial, as well as exploring additional areas such as the correlation of the number of radiation procedures by site irradiated with increased cost, the relative costs of various radiation regimens and fractionation schedules, the cost-effectiveness of radiation therapy compared to alternative therapies for bone metastases, costs incurred without radiation therapy e.g. cord compression, and cost differences between private payers, Medicare and Medicaid, and/or academic and non-academic facilities.

The results of this study show that in the United States, palliative radiation treatment of bone metastases in patients with breast or prostate cancer represents a significant cost burden. Furthermore, the study provides a foundation for evaluating the relative costs of current and investigational therapies for the treatment of bone metastases.