Clinical practice patterns and cost effectiveness of human epidermal growth receptor 2 testing strategies in breast cancer patients.
BACKGROUND
Testing technologies are increasingly used to target cancer therapies. Human epidermal growth factor receptor 2 (HER2) testing to target trastuzumab for patients with breast cancer provides insights into the evidence needed for emerging testing technologies.


METHODS
The authors reviewed literature on HER2 test utilization and cost effectiveness of HER2 testing for patients with breast cancer. They examined available evidence on: percentage of eligible patients tested for HER2; test methods used; concordance of test results between community and central/reference laboratories; use of trastuzumab by HER2 test result; and cost effectiveness of testing strategies.


RESULTS
Little evidence was available to determine whether all eligible patients are tested, how many are retested to confirm results, and how many with negative HER2 test results still receive trastuzumab. Studies suggested that up to 66% of eligible patients had no documentation of testing in claims records, up to 20% of patients receiving trastuzumab were not tested or had no documentation of a positive test, and 20% of HER2 results may be incorrect. Few cost-effectiveness analyses of trastuzumab explicitly considered the economic implications of various testing strategies.


CONCLUSIONS
There was little information about the actual use of HER2 testing in clinical practice, but evidence suggested important variations in testing practices and key gaps in knowledge exist. Given the increasing use of targeted therapies, it is critical to build an evidence base that supports informed decision making on emerging testing technologies in cancer care.
Phillips
Kathryn A
KA
Department of Clinical Pharmacy, University of California San Francisco, San Francisco, CA 94143-0613, USA. PhillipsK@pharmacy.ucsf.edu
Marshall
Deborah A
DA
Haas
Jennifer S
JS
Elkin
Elena B
EB
Liang
Su-Ying
SY
Hassett
Michael J
MJ
Ferrusi
Ilia
I
Brock
Jane E
JE
Van Bebber
Stephanie L
SL
D000911:Antibodies, Monoclonal / Q000191:economics* / Q000627:therapeutic use; D061067:Antibodies, Monoclonal, Humanized; D000970:Antineoplastic Agents / Q000191:economics / Q000627:therapeutic use*; D014408:Biomarkers, Tumor / Q000032:analysis*; D001943:Breast Neoplasms / Q000188:drug therapy* / Q000191:economics* / Q000378:metabolism*; D003362:Cost-Benefit Analysis; D016503:Drug Delivery Systems / Q000191:economics* / Q000706:statistics & numerical data; D006801:Humans; D010818:Practice Patterns, Physicians' / Q000191:economics*; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000032:analysis*; D000068878:Trastuzumab
D000911:Antibodies, Monoclonal; D061067:Antibodies, Monoclonal, Humanized; D000970:Antineoplastic Agents; D014408:Biomarkers, Tumor; D018719:Erb-b2 Receptor Tyrosine Kinases; D000068878:Trastuzumab; C508053:ERBB2 protein, human