title: Reflex immunohistochemistry and microsatellite instability testing of colorectal tumors for Lynch syndrome among US cancer programs and follow-up of abnormal results.
abstract: OBJECTIVE
  Immunohistochemistry (IHC) for MLH1, MSH2, MSH6, and PMS2 protein expression and microsatellite instability (MSI) are well-established tools to screen for Lynch syndrome (LS). Although many cancer centers have adopted these tools as reflex LS screening after a colorectal cancer diagnosis, the standard of care has not been established, and no formal studies have described this practice in the United States. The purpose of this study was to describe prevalent practices regarding IHC/MSI reflex testing for LS in the United States and the subsequent follow-up of abnormal results.
  
  
  METHODS
  A 12-item survey was developed after interdisciplinary expert input. A letter of invitation, survey, and online-survey option were sent to a contact at each cancer program. A modified Dillman strategy was used to maximize the response rate. The sample included 39 National Cancer Institute-designated Comprehensive Cancer Centers (NCI-CCCs), 50 randomly selected American College of Surgeons-accredited Community Hospital Comprehensive Cancer Programs (COMPs), and 50 Community Hospital Cancer Programs (CHCPs).
  
  
  RESULTS
  The overall response rate was 50%. Seventy-one percent of NCI-CCCs, 36% of COMPs, and 15% of CHCPs were conducting reflex IHC/MSI for LS; 48% of the programs used IHC, 14% of the programs used MSI, and 38% of the programs used both IHC and MSI. One program used a presurgical information packet, four programs offered an opt-out option, and none of the programs required written consent.
  
  
  CONCLUSIONS
  Although most NCI-CCCs use reflex IHC/MSI to screen for LS, this practice is not well-adopted by community hospitals. These findings may indicate an emerging standard of care and diffusion from NCI-CCC to community cancer programs. Our findings also described an important trend away from requiring written patient consent for screening.
authors.affiliation: City of Hope, Duarte, CA 91010, USA.
authors.forename: Laura C
authors.initials: LC
authors.lastname: Beamer
authors.forename: Marcia L
authors.initials: ML
authors.lastname: Grant
authors.forename: Carin R
authors.initials: CR
authors.lastname: Espenschied
authors.forename: Kathleen R
authors.initials: KR
authors.lastname: Blazer
authors.forename: Heather L
authors.initials: HL
authors.lastname: Hampel
authors.forename: Jeffrey N
authors.initials: JN
authors.lastname: Weitzel
authors.forename: Deborah J
authors.initials: DJ
authors.lastname: MacDonald
mesh_terms: D000328:Adult; D000368:Aged; D015179:Colorectal Neoplasms / Q000235:genetics* / Q000473:pathology*; D003123:Colorectal Neoplasms, Hereditary Nonpolyposis / Q000235:genetics / Q000473:pathology; D003430:Cross-Sectional Studies; D005260:Female; D005820:Genetic Testing / Q000706:statistics & numerical data*; D019538:Health Care Surveys; D006801:Humans; D007150:Immunohistochemistry / Q000706:statistics & numerical data*; D007258:Informed Consent / Q000706:statistics & numerical data; D016015:Logistic Models; D008297:Male; D053842:Microsatellite Instability; D008875:Middle Aged; D015397:Program Evaluation; D012017:Referral and Consultation / Q000706:statistics & numerical data; D059039:Standard of Care / Q000639:trends*; D014481:United States / Q000453:epidemiology