3394F Quantitative HER2 immunohistochemistry (IHC) evaluation of breast cancer consistent with the scoring system defined in the ASCO/CAP guidelines (PATH)

Name of the Procedure:

Quantitative HER2 Immunohistochemistry (IHC) Evaluation of Breast Cancer

Summary

Quantitative HER2 Immunohistochemistry (IHC) Evaluation is a laboratory test used to determine the level of HER2 protein expression in breast cancer tissues. HER2 is a protein that can influence the growth of cancer cells. By assessing this, doctors can better decide on the most effective treatment plan.

Purpose

This procedure is designed to evaluate the HER2 status of breast cancer. HER2-positive tumors may respond well to targeted therapies. Determining HER2 status helps in planning appropriate treatment and predicting the patient’s prognosis.

Indications

• Diagnosis of breast cancer.
• Assessing HER2 status to guide therapy decisions.
• Re-evaluation of HER2 status in recurrent or metastatic breast cancer.

Preparation

• No specific preparation is typically required from the patient.
• The tissue sample is usually obtained during a biopsy or surgery.
• The patient should inform their healthcare provider about any medications they are taking, but no adjustments are generally needed.

Procedure Description

1. A tissue sample from the breast cancer is collected during a biopsy or surgery.
2. The sample is chemically treated and stained with antibodies that bind to the HER2 protein.
3. Under a microscope, a pathologist quantitatively evaluates the stained sample based on the ASCO/CAP guidelines.
4. The HER2 expression is scored, with a score of 0 or 1+ being considered HER2-negative, 2+ as equivocal, and 3+ as HER2-positive.

Duration

The evaluation of the tissue sample typically takes several hours to a few days, depending on the laboratory's workflow.

Setting

The procedure is performed in a pathology laboratory.

Personnel

• Pathologists
• Laboratory technicians

Risks and Complications

• Generally low risk as the procedure involves laboratory analysis of a previously obtained tissue sample.
• A possible risk is a false result, which can lead to a misdirected treatment plan.

Benefits

• Accurate HER2 status determination aids in selecting effective therapy.
• Improves the likelihood of a positive outcome by guiding the use of targeted therapies.

Recovery

• No recovery is needed as the patient is not directly involved in the laboratory analysis.
• Normal activities can be resumed immediately after the tissue sample collection (biopsy or surgery).

Alternatives

• Fluorescence In Situ Hybridization (FISH) can also be used to assess HER2 status.
• Pros: FISH is another reliable method for HER2 testing.
• Cons: It can be more expensive and time-consuming than IHC.

Patient Experience

• The patient is not involved in the actual IHC evaluation process, and thus experiences no discomfort from this specific procedure.
• Any discomfort or pain would be associated with the initial biopsy or surgical procedure to obtain the tissue sample. Pain management for these procedures will be addressed separately.