Muddy Water? Variation in Reporting Receipt of Breast Cancer Radiation Therapy by Population-Based Tumor Registries

Abstract

Purpose Receipt of radiation therapy (RT) is a key quality indicator in breast cancer treatment. Prior analyses using population-based tumor registry data have demonstrated substantial underuse of RT for breast cancer, but the validity of such findings remains debated. To address this controversy, we evaluated accuracy of registry RT coding compared to the gold standard of Medicare claims. Methods and Materials Using SEER-Medicare data, we identified 73,077 patients age ≥ 66 diagnosed with breast cancer from 2001-2007. Underascertainment (1-sensitivity), sensitivity, specificity, kappa, and chi-square were calculated for RT receipt determined by registry data vs. claims. Multivariate logistic regression characterized patient, treatment, and geographic factors associated with underascertainment of RT. Findings in the SEER-Medicare registries were compared to three non-SEER registries (Florida, New York, and Texas). Results In the SEER-Medicare registries, 41.6% (n=30,386) of patients received RT according to registry coding versus 49.3% (n=36,047) according to Medicare claims (P<0.001). Underascertainment of RT was more likely if patients resided in a newer SEER registry (OR 1.70, 95%CI 1.60-1.80;P<0.001), rural county (OR 1.34, 95%CI 1.21-1.48;P<0.001) or if RT was delayed (OR 1.006/day, 95%CI 1.006-1.007,P<0.001). Underascertainment of RT receipt in SEER registries was 18.7% (95% CI 18.6-18.8%), compared to 44.3% (95% CI 44.0-44.5%) in non-SEER registries. Discussion Population-based tumor registries are highly variable in ascertainment of RT receipt and should be augmented with other data sources when evaluating quality of breast cancer care. Future work should identify opportunities for the radiation oncology community to partner with registries to improve accuracy of treatment data.

Trends in Radiation Therapy among Cancer Survivors in the United States, 2000–2030

“…For example, our breast cancer projections assume that radiation therapy will play the same role in local control as it does in current practice. Third, recent studies in breast cancer suggest that SEER may underestimate the true rates of radiation delivery (41,42). In addition, SEER only records radiation during a patient's first course of treatment, which implies that patients receiving radiation for recurrent or metastatic disease beyond their first course of treatment would not be included.…”

Utilization and impact of a postmastectomy radiation boost for invasive breast cancer

“…The overall adjusted model had a HR for BSC of 1.04, 95% CI, 0.86-1. 26 Based on our finding regarding tumor size and chemotherapy in univariate analyses, we created multivariate models for each of these strata. For women who did not receive chemotherapy, those who did not receive a CWB had a HR for breast cancer death of 1.50, 95% CI, 0.91-2.47.…”

“…[26][27][28] Our data are a single registry and may have inaccuracy compared with prospectively collected cooperative group data, or even single institution data. A study by Malin et al 27 examined the California Cancer Registry and found that data were accurate for hospital-based settings, and that the receipt of radiation therapy was 72% as verified by the medical record.…”

“…In a recent study that examined the receipt of radiation therapy using SEER registries, 41.6% of patients received RT according to registry coding versus 49% per Medicare claims, P b .001. 26 Radiation reporting was influenced by the reporting in newer SEER registries, rural setting, or if the radiation was delayed. 26 Again, the purpose of this study was not to evaluate the receipt of radiation treatment but to evaluate the use and role of a CWB among women who received RT.…”

“…26 Radiation reporting was influenced by the reporting in newer SEER registries, rural setting, or if the radiation was delayed. 26 Again, the purpose of this study was not to evaluate the receipt of radiation treatment but to evaluate the use and role of a CWB among women who received RT. Despite the caveats with registry data, a valid strength of this study is its population base; breast cancer cases from the entire state of California.…”