CPT® Code 81518

1. Indications

The mRNA gene expression profiling test described by CPT® Code 81518 is indicated for specific patient populations and clinical scenarios. The following conditions and characteristics are explicitly associated with the use of this test:

• Stage I or II Breast Cancer The test is primarily performed on patients diagnosed with Stage I or II breast tumors, which are early stages of breast cancer.
• Estrogen Receptor Positive (ER+) The tumors must be positive for estrogen receptors, indicating that the cancer cells may grow in response to estrogen.
• HER2 Negative (HER2-) The test is indicated for tumors that are negative for human epidermal growth factor receptor 2, suggesting a different treatment approach compared to HER2-positive cancers.
• Limited Lymph Node Involvement The test is appropriate for tumors that are either negative for lymph node involvement or have no more than three lymph nodes that are positive for disease.

2. Procedure

The procedure for conducting the mRNA gene expression profiling test using CPT® Code 81518 involves several critical steps to ensure accurate results. Each step is outlined as follows:

• Sample Collection A formalin-fixed paraffin-embedded tissue sample is obtained from the patient. This sample is typically taken from the tumor site during a biopsy or surgical procedure. The preservation method allows for the long-term storage of the tissue while maintaining its cellular integrity for analysis.
• RNA Extraction The next step involves extracting the messenger RNA (mRNA) from the collected tissue sample. This process is crucial as it isolates the genetic material that will be analyzed for gene expression levels.
• Real-Time RT-PCR Analysis The extracted mRNA undergoes real-time reverse transcription polymerase chain reaction (RT-PCR). This technique amplifies the mRNA, allowing for the quantification of the expression levels of the 11 specific genes included in the assay. The analysis distinguishes between the 7 content genes and the 4 housekeeping genes, ensuring that the results are reliable and accurate.
• Algorithm Development Following the RT-PCR analysis, the data is processed using algorithms that calculate a percentage risk score for metastatic recurrence. This score reflects the likelihood of cancer returning after treatment and is essential for guiding treatment decisions.
• Reporting Results The final step involves compiling the results into a report that details the risk score and the likelihood of benefit from extended endocrine therapy. This report is then provided to the treating clinician for further evaluation and decision-making regarding the patient's treatment plan.

3. Post-Procedure

After the mRNA gene expression profiling test is completed, the treating clinician will review the results in conjunction with other clinical factors such as the patient's age, tumor size, and lymph node involvement. The information obtained from the test is instrumental in determining the appropriateness of extended endocrine therapy for the patient. The clinician may discuss the findings with the patient, including the implications of the risk score and potential treatment options. It is important for the patient to understand how these results may influence their ongoing treatment strategy and any necessary follow-up care. Additionally, the clinician will monitor the patient for any side effects related to the treatment decisions made based on the test results.