Decades of research have shown that significant disparities in cancer care exist based on where patients are treated. In particular, people who receive care at hospitals that specialize in cancer and treat a large number of cases have better long-term survival rates.
At the same time, there has been uncertainty about what these differences actually mean. Traditional methods of assessing hospital performance have often relied on data that is not comprehensive and leaves room for doubts about whether certain complicating factors — such as the stage of patients’ tumors — make it difficult to draw valid conclusions when comparing outcomes.
Now a new study by Memorial Sloan Kettering researchers suggests that hospitals’ long-term survival outcomes for cancer patients can be assessed without data on tumor stage, by using readily available, unbiased Medicare claims data. The study, reported online October 8 in JAMA Oncology, could be a critical step toward ultimately improving patient care nationwide.
“Patients need reliable information about hospitals’ survival rates so they can make informed choices about their care,” says David Pfister, Chief of MSK’s Head and Neck Oncology Service and lead author of the study. “But similarly important, measuring the differences in survival rates among hospitals is a first step toward improving cancer care at every hospital across the country.”
Limitations of Conventional Measurement
Survival rates for cancer patients can be readily ascertained from Medicare claims data, which relates to treatments that patients receive over the course of their care. But researchers have hesitated to rely solely on this data when comparing patient outcomes.
The reason for this has to do with the risk-adjustment process researchers use to account for variation in outcomes that is related more to the types of patients they treat — such as those with more advanced disease — than true differences in the quality of care they receive. In cancer, the concern has been that standard risk adjustment could not be adequately accomplished without information on each patient’s cancer stage.
A hospital with a large share of patients with advanced-stage tumors, for example, could have a lower survival rate than a hospital with a greater proportion of patients with less-advanced disease — even though the two hospitals provide equally good care.Back to top
The Tumor Stage Test
For the JAMA Oncology study, the MSK researchers analyzed two parallel data sets: fee-for-service Medicare claims from across the United States, which do not include information on cancer stage; and the Surveillance, Epidemiology, and End Results (SEER) Medicare database, which does include that information. The claims data covered the entire spectrum of inpatient and outpatient cancer care, including office visits, chemotherapy, radiation, and even home care.
The researchers calculated the risk-adjusted probability of death over three years and five years for four major cancer types — lung, prostate, breast, and colon — as well as for an “other” category, broken out by the type of hospital providing care. Each patient was assigned to a single hospital where they received care, and the hospitals were categorized into four types:
- PPS-exempt, which are freestanding cancer hospitals that are exempt from the Medicare prospective payment system
- National Cancer Institute–designated cancer centers that are not PPS-exempt
- Academic Medical Centers, or AMCs, which are other academic teaching hospitals
- other category, which included community hospitals
Including Tumor Stage Did Not Change Hospital Status
The MSK researchers analyzed risk-adjusted Medicare data both with and without tumor stage information and found that the disease stage had no effect on outcomes from individual hospitals. The results showed that hospital standing based on survival outcomes remained stable, providing strong evidence that incorporating tumor stage information is not essential for accurate assessment.
Findings showed that patients treated at the 11 PPS-exempt hospitals had a 10 percent lower chance of dying in the first year than patients treated at other non-teaching hospitals (18 percent versus 28 percent), with NCI cancer centers and AMCs falling between the two extremes.Back to top
Implications for Public Health
The findings have significant long-term implications for public health. The authors believe acknowledging that significant survival differences do exist among hospitals is an important first step in improving outcomes and worthy of deeper exploration.
“This observed one-year survival gap of 10 percent between hospital types is substantial and represents potentially preventable deaths of cancer patients,” says Peter Bach, director of MSK’s Center for Health Policy & Outcomes and senior author of the paper.
“If further research confirms this survival gap, a next step would be to figure out the mechanics underpinning it,” he adds. “Is it due to readmissions or mortality rates after surgery? Are people having severe side effects keeping them from finishing the chemotherapy that benefits them? We need to break down the data and figure out where the gaps in care exist.”
Similar outcomes research using only administrative claims data is already under way nationally in cardiovascular disease. For example, the Centers for Medicare and Medicaid Services publish risk-adjusted cardiovascular disease mortality rates for US hospitals.
“We hope to eventually do the same thing in cancer,” Dr. Bach says. “More validation is needed of the risk adjustment metrics for hospitals, but I think we can certainly challenge the idea that we need patient-level data on cancer stage to evaluate hospitals.”Back to top