Using practice guidelines to define appropriate care, we found that over 90% of all patients received recommended care for 7 of the 11 guidelines examined at an aggregate patient level. We also identified 6 measures for which at least half the institutions were concordant with the guidelines 100% of the time. These high concordance rates suggest that the factors influencing clinical decision-making are adequately captured in the current guidelines and surgeons recognize the importance of these therapies. As a result, we were able to demonstrate that Medicare beneficiaries are highly likely to receive appropriate care and that this finding is consistent across hospitals.
For several of the guidelines related to nodal management, however, concordance rates were low and few hospitals provided appropriate care to all patients. Specifically, we found that published guidelines recommending examination of a minimum number of lymph nodes in colon and gastric cancer have not resulted in routine adoption of this practice in elderly Americans despite the inclusion of these recommendations in the AJCC staging manual . It is possible that despite apparent expert consensus regarding the importance of evaluation of a minimum number of nodes, the lack of definitive evidence supporting a particular threshold has left many practitioners (surgeons and/or pathologists) unconvinced. They may not believe the potential benefits of more extensive lymph node harvests outweigh the added operative risks, perhaps particularly in older patients. The limitations of the evidence base supporting nodal evaluation and the difficulty in defining an appropriate nodal threshold for use in guidelines or quality measurement are well-described in two recent reviews, a report from the Cochrane Collaboration regarding extent of lymph node dissection for gastric cancer and a meta-analysis on colon cancer nodal evaluation. 19-20
We observed a somewhat different pattern of concordance for central neck dissection for node positive papillary thyroid cancer, with a higher aggregate concordance rate of 71.6%. In the hospital-level analysis, but no institutions at all performing neck dissections in all of their patients. Instead, most institutions performed them in approximately 80% of patients. One possible explanation for these findings is that there is agreement that a central neck dissection constitutes appropriate care for most but not all elderly patients with node positive papillary thyroid cancer, and that the factors relevant to selecting patients for the procedure are not adequately captured by the current guideline inclusion criteria, at least in this population of elderly Americans. Such factors might include the presence of a macro-rather than micrometastasis, or nodes detectable pre-operatively or at the time of surgery, rather than only on post-operative pathology review.
Several other explanations could account for the patterns observed in this study. Prior research on the Hospital Quality Alliance measures has suggested an association between the length of time guidelines have been in place and concordance rates.21
We found high concordance rates and minimal variation for the breast measures, guidelines that were among the first to be developed in cancer care.
It's also possible that because referral for adjuvant therapy is a dichotomous decision, which facilitates both compliance and measurement, it's easier for institutions to achieve consistent and high concordance rates on these measures than on guidelines measuring a continuous outcome such as number of lymph nodes examined. Alternatively or in addition, the fact that referrals result in reimbursement for the provider or the health system while lymph node harvests do not may contribute to the higher concordance we observed for guidelines related to adjuvant therapy.
Finally, there is a suggestion in our data that the level of evidence on which a guideline is based is associated with the level of concordance. Six of the 8 guidelines with concordance rates > 90% were based on high level evidence and all 3 of the guidelines with concordance rates <90% were based on lower level evidence (). Similarly, 5 of the 6 guidelines where more than 50% of institutions provided concordant care to 100% of their patients were graded as 1, while 4 of the 5 guidelines for which less than half of the institutions provided fully concordant care were graded 2 (). The role that level of evidence may play in acceptance of guidelines deserves further investigation.
This study has the usual limitations associated with analyses of large national databases, including incomplete capture of cases, loss of follow up, and missing data as well as the limitations of claims data such as variation in billing practices and coding inaccuracies. Additionally, because Medicare provides the only consistent and comprehensive national data source on medical services delivered, our analysis was limited to patients 65 and older. A focus on older patients did allow us to study a particularly vulnerable population and one that makes up the majority of patients with gastric and colorectal cancer. However, breast and thyroid cancer are common in younger Americans, so our reliance on Medicare data represents a more significant limitation for these diagnoses.
We found a high level of concordance with guidelines in some domains of surgical oncology care, but far less so in others, especially those that are associated with nodal management. Five of the six measures with wide acceptance into practice relate to appropriate referral for or receipt of adjuvant therapy. Given the current national focus on quality in healthcare, there is increasing pressure to develop measures to determine whether patients are getting appropriate care; however, within the surgical disciplines, there is a paucity of data to support what constitutes appropriate care. It is critical that surgeons focus on the generation of the data necessary to inform clinical decision-making and promote quality surgical care.