RAMB - JULHO 2017

ssessment

HER-2

status

invasive

breast

cancer

razil

ssoc

ras

2017; 63(7):566-574

567

stages of the disease.

12-14

As a result of these potential

benefits, HER-2 testing is currently recommended for

primary, recurrent and metastatic breast cancer lesions.

In order to establish tumor HER-2 status in the clinic,

a prerequisite for anti-HER-2 therapy, a paraffin-embed-

ded tissue block of invasive breast carcinoma is required.

When the primary tumor is assessed, specimens may be

obtained through a core-needle biopsy, as well as from

an incisional or excisional surgical procedure.

More often,

one of two methods is routinely used for the assessment

of HER-2 status: immunohistochemistry (IHC) and one

of the variants of in situ hybridization (ISH), namely

fluorescent ISH (FISH), chromogenic ISH, and silver ISH.

IHC is more widely available; however, it is more prone

to interpretation error. Conversely, ISHmethods have the

disadvantages of requiring better tissue quality, being

more expensive and technically demanding than IHC

and of being limited to only a few centers.

Because each

assay type has diagnostic pitfalls, an algorithm has been

proposed by the American Society of Clinical Oncology

(ASCO) and the College of American Pathologists (CAP).

As a result, samples classified as negative or positive by

validated IHC analysis of their invasive tumor component

require no further testing, whereas equivocal tests (i.e.,

samples classified as 2+ by IHC) should be followed by

ISH testing.

There is a wealth of information in the literature re-

garding the frequency and determinants of HER-2 positiv-

ity in many countries and settings. On the other hand,

only a few studies have been conducted in Brazil, most of

which relatively small in size or retrospective in nature.

16-18

In the current study, we prospectively attempted to inves-

tigate the frequency of HER-2-positive breast cancer in a

large sample of Brazilian women, along with the stan-

dardization of preanalytic procedures used in the assess-

ment of HER-2 and the association between HER-2 status

and various tumor and patient features, including geo-

graphic location.

ethod

Role of the sponsor and ethical aspects

This study was sponsored by Roche Brazil, which par-

ticipated in the design, analysis and publication of results.

The sponsor appointed a Scientific Committee, composed

by pathologists and a medical oncologist, which was re-

sponsible for study oversight and which vouches for the

accuracy of the data and the current manuscript. All par-

ticipating patients provided written informed consent,

and the study was approved by the Ethics Committees of

all participating institutions. The initial version of the

manuscript and subsequent changes based on input from

all authors was under the responsibility of a medical-

-writing company (Dendrix, São Paulo).

Study oversight

In order to standardize the technique, the sponsor pro-

vided initial training with regard to study procedures,

including the performance of IHC and ISH for HER-2, to

all participating institutions. Positive and negative con-

trols were provided by the Scientific Committee to par-

ticipating laboratories. During the conduction of the

study, the Scientific Committee regularly assessed the

quality of the local readings, providing further training,

if necessary.

Selection of patients and samples

In this prospective, observational study, an attempt was

made to sequentially collect all samples of primary invasive

breast cancer identified at participating pathology labo-

ratories in the five geographic regions of Brazil during a

defined period of time (from February, 2011, to December,

2012). Eligible patients were women with no neoadjuvant

therapy regimen, and surgical specimens had to be obtained

by radical mastectomy or segmentectomy, or histological

material obtained by core-needle biopsy, or conventional

surgical biopsy. Samples for which there was insufficient

residual material for IHC and ISH were excluded from

analysis. For each sample, locally collected data were cen-

trally registered regarding preanalytic procedures, tumor

size and location, margin status, histological type, archi-

tectural, nuclear and histological grade,

mitotic activity,

presence of necrosis, lymphatic invasion and lymphoplas-

macytic response, the number and nature (sentinel or not)

of dissected and involved lymph nodes, and the presence

and features of ductal carcinoma in situ (DCIS). IHC for

estrogen receptor (ER), progesterone receptor (PR) and

Ki-67 was performed at each participating laboratory us-

ing local standards, with expression of ER/PR in more

than 1% of cells being considered positive. Data were cen-

trally collected regarding antibody used, dilution, incuba-

tion time and temperature, antigen retrieval, amplification

system, and result (negative or positive, according to the

percentage of reactivity in the invasive neoplasm).

IHC analysis for HER-2

For HER-2, the IHC procedure was performed locally at

each participating laboratory in an automated fashion,

using Ventana equipment (Ventana Medical Systems,

Tucson, AZ). Fixation was performed using 10% neutral

buffered formalin at 15 to 20 times the volume of tissue