Patient selection: invasive breast cancer
Situations when repeating HER2 testing is appropriate:
(1) An initial biopsy specimen was negative for HER2 AND one or more of the following is present:
(1a) The carcinoma is Grade 3.
(1b) The amount of tumor in the first biopsy was small.
(1c) The tumor in the subsequent resection is distinct from the tumor in the initial specimen and higher grade.
(2) Previous HER2 results are positive AND the carcinoma is Grade 1 AND the tumor is one of the following:
(2a) ER and PR positive infiltrating ductal carcinoma
(2b) ER and PR positive infiltrating lobular carcinoma
(2c) >= 90% pure tubular carcinoma (Grade 1 infiltrating ductal)
(2d) >= 90% pure mucinous carcinoma
(2e) >= 90% pure cribriform carcinoma
(2f) >= 90% pure adenoid cystic carcinoma carcinoma
(3) Testing error is suspected in the initial test.
(4) The initial specimen may have been mishandled.
(5) The initial test was equivocal after initial and subsequent testing.
Repeat testing is not indicated in the second group if the initial results were negative.
