R. L. Hoffman1, K. D. Simmons1, G. C. Karakousis1, N. N. Mahmoud1, R. R. Kelz1 1Hospital Of The University Of Pennsylvania,Philadelphia, PA, USA
Introduction: Stage-specific, evidence-based guidelines to assist with the delivery of quality cancer care were first released in 1996. Adherence to guideline-based therapy has been shown to have an impact on overall and recurrence free survival for colon cancer patients. In order to identify high yield regions for educational campaigns regarding colon cancer guidelines, we analyzed the geographic distribution of guideline-adherent care using spatial autocorrelation.
Methods: Patients aged 65-84 years diagnosed with AJCC stage II and III colon cancer were identified within the SEER-Medicare database (2005-2009). High risk stage II disease was defined as those with a T4 tumor, poor differentiation and <12 lymph nodes examined. Guideline adherence was assigned using stage-specific NCCN guidelines. The percentage of adherence was calculated for each state and county within the SEER registry catchment areas containing more than 10 patients, and translated to a choropleth map. Tests of spatial autocorrelation with queen contiguity-based spatial weights were used to evaluate geographic clustering of guideline-concordant therapy delivery. The Moran’s I and the local indicator of spatial autocorrelation (LISA) were calculated.
Results:There were 17,715 patients identified. A total of 4,933 (28%) were low risk Stage IIA/IIB, 4,446 (34%) were high risk stage IIA/IIB, and 8,336 (47%) were stage IIIA/B/C. A total of 13,017 (73%) patients underwent colectomy, 3,549 (27%) had ≤12 lymph nodes removed, 3,988 (31%) received chemotherapy, and 485 (4%) were treated with radiation. A total of 331 (3%) were treated with all modalities. Of all those who underwent surgery, 6,348 (49%) received guideline concordant treatment and 6,669 (51%) were discordant (5,837; 45% undertreated, 832; 6% overtreated). Stage IIA/B patients received concordant therapy 53% of the time and are undertreated in 39% of cases while Stage III patients receive concordant care 44% of the time and are undertreated in 52%. Twelve states were represented in the SEER registry and 73 counties. Adherence rates ranged from 43% to 56% by state and ranged from 16% to 87% by county. The value of Moran’s I was 0.187. Clustering of concordant care varied throughout the US (Fig 1).
Conclusion:There is variation in the treatment of stage II and III colon cancer across geographic locations within the United States. Variation seems to be unrelated to the presence of NCI Designated Comprehensive Cancer Centers. Graphical representation of NCCN guideline concordance patterns using spatial autocorrelation represents a new approach to identifying high yield regions for education campaigns. Issues related to cancer care access may be more specifically targeted using this knowledge.
