This article discusses how tests such as the Oncotype DX or Mammaprint can be used to design individual treatment plans for patients with breast cancer.
Patients with stage I and stage II breast cancer are treated similarly. Following surgical removal of a breast tumor, systemic (body-wide) treatment is often used. This secondary treatment is called 'adjuvant'. Adjuvant care aims to kill any residual cancer cells that may have escaped surgical removal and to prevent recurrence. Chemotherapy and endocrine therapy (hormone therapy) are used for adjuvant care of breast cancer. The choice of adjuvant care depends on:
1) The size of the tumor
2) Whether the tumor has spread to other parts of the body (metastasized)
3) The type of receptors on the surface of the cancer cells. The 3 most important receptors found on breast cancer cells are the estrogen receptor (ER), progesterone receptor (PR) and HER2. These receptors are proteins that promote tumor growth.
Adjuvant hormone therapy with anti-estrogen treatment such as Tamoxifen is recommended to most women with a tumor that is hormone receptor positive. Additional chemotherapy is recommended to those who also have a high recurrence score, or as adjuvant care if the tumor is hormone receptor-negative. If the tumor is HER2 positive, targeted treatment with a drug such as Trastuzumab (Herceptin) plus chemotherapy is generally recommended.
The recurrence score is calculated using genetic tests which measure levels of genes in a biopsy (tumor sample). These tests include the Oncotype DX which is a 21-gene test and Mammaprint which is a 70-gene test. These tests identify tumor markers that can be used to predict how quickly the cancer might spread.
There is still disagreement if there is sufficient need for this type of diagnosis.This method of identifying biomarkers could however help identify tumors which are rare and require specific treatment. It may also help to identify what causes cancer cells to be resistant to treatment.
Published By :
Annals of oncology
Date :
Sep 01, 2012
