Biased View of the Role of Site-Specific Therapy in Carcinoma of Unknown Primary
Authors: Mary-Elizabeth Percival, A. Dimitrios Colevas
Journal: Journal of Clinical Oncology (2013)

The letter by Sura et al 1 raised three concerns about our article on the unintended consequences of Veteran Affairs (VA) colorectal cancer (CRC) Oncology Watch (OncWatch) intervention, implemented in the Veterans Integrated Service Network 7 (VISN 7) during fiscal year 2008. 2 The following are our point-by-point responses.First, Sura et al stated that improving CRC screening adherence rates, as evaluated by our article, was not among the aims of OncWatch.We believe that this statement is not supported by the available evidence, andwestandbyouroriginaldescriptionofthetwoaimsofOncWatch:(1) improving screening adherence rates for the average-and high-risk veterans, and (2) providing timely diagnostic and surveillance follow-ups.The two aims were well referenced in an original review article cited in our article, one of whose coauthors was Luke Stapleton, MD, the Clinical Program Director of VISN 7, who had primary responsibilities for designing and implementing OncWatch. 3 In addition, Maria Ribeiro, MD, a member of the original OncWatch committee and a coauthor of our article, has carefully re-examined numerous internal OncWatch documents.It is amply clear from this review article and Ribeiro's first-hand experience that improving CRC screening adherence rates was one of OncWatch's central aims.That said, it is possible that some VISN 7 providers would have found it challenging to follow all OncWatch protocols.In hindsight, our article could have pointed out that variation in providers'compliancewithOncWatchmighthaveinfluencedourresults.Second, Sura et al raised a concern about the validity of the controls.In the context of the response to the first concern, our choice of the controls (ie, the non-VISN 7 hospitals) was valid because the aim of OncWatch for improving CRC screening adherence rates, using VA electronic health records, is unique within VISN 7. (Please see the discussion of potential contamination biases in our article.)Third, Sura et al were concerned about the accuracy of our estimated CRC screening adherence rates.The claims data used by our article are, by design, different from the electronic health records database used by OncWatch and Sura et al.However, we have made our best efforts to design an algorithm for estimating CRC screening adherence for average-risk veterans using claims data, in a way that mimics the inclusion/exclusion criteria set by OncWatch.(See a detailed presentation and critical appraisal of this algorithm cited in our article. 4) In addition, our article carefully considered the possibility of incomplete information on veterans who used different systems, including VA-contracted providers.Specifically, we included VA Fee Basis data in our analysis and performed a set of sensitivity analyses to test how well our algorithm performed in identifying veterans who relied primarily on the VA for health care. 2,4 On the other hand, the CRC screening adherence rates presented by Sura et al are difficult to interpret.For example, what were the exclusion and inclusion criteria used in estimating the rates?This is especially important to ensure that diagnostic and surveillance colonoscopy procedures were excluded from estimating CRC screening rates for average-risk veterans only.What were the denominators in different years?How long were the retrospective look-back windows used to determine annual adherence status for modalities recommended for longer than 1 year?In summary, the aim of our article was to report an objective evaluation of the impact of OncWatch on CRC screening rates for average-risk veterans, and we stand by our analyses and findings, subject to the limitations noted in our article.Moreover, our article illustrates how the application of a well-defined research methodology can yield evidence useful for evaluating large-scale interventions.