Category Archives: Breast Cancer Drugs

What are the side effects of tamoxifen?

Side effects and Risks of tamoxifen

Tamoxifen acts like an anti-estrogen in some tissues and acts like estrogen in other tissues.

  • Hot flashes and night sweats
  • Cancer of the uterus (most were endometrial cancer, a few were uterine sarcoma).  The risk is not present in those patients who have had  a hysterectomy.
  • Blood clots (DVT, PE, and stroke)

Tamoxifen is contraindicated in patients who continue to smoke due to the increased risk of thromboembolic disease.

What is Perjeta, a breast cancer drug?

Perjeta is Pertuzumab

Perjeta is Pertuzumab

  • It is a targeted therapy to be used before surgery and in combination with other HER2 postive breast cancer drugs such as Herceptin (trastuzumab).
  • Perjeta has a different way of working than the other HER2 positive breast cancer medications.
  • Pertuzumab is a monoclonal antibody (like trastuzumab). The first of its class in a line of agents called “HER dimerization inhibitors.”
  • Both Perjeta and Herceptin target HER2 but work in complementary ways.  The combination may increase the death of cancer cells.
  • Perjeta is contraindicated in pregnancy.
  • FDA approved for Genentech (makers of Herceptin, too) on September 12, 2013.
  • Before surgery usage is called neoadjuvant or now called primary systemic therapy.

What is Trastuzumab – a breast cancer drug?


Herceptin is Trastuzumab for breast cancer

  • Trastuzumab has a trade name of Herceptin.
  • It is a monoconal antibody that interferes with the HER2/neu receptor.
  • Her proteins stimulate cell proliferation.  In certain types of breast cancers, HER2 is over expressed and causes the cancer cell to reproduce uncontrollably.
  • Trastuzumab is associated with cardiac dysfunction in 2-7% of cases.  Regular cardiac screening with an echocardiogram or MUGA scan is commonly undertaken during the trastuzumab treatment duration.
  • Optimal treatment duration of Herceptin isn’t known but one year of treatment is generally accepted as the optimum length of therapy based on clinical trials.
  • FDA approval was received in 1998 by Genentech with UCLA.

HER2 positive breast cancers vs. HER-2 negative

HER2 positive breast cancers have a worse prognosis.  HER2 positive breast cancers are likely to have high proliferative rate, positive axillary lymph nodes, and decreased expression extrogen and progesterone receptors.

Of invasive breast cancers what percentage are HER2 positive?

15-20% of invasive breast cancers are HER2 positive.

Lobular Carcinoma In Situ, a incidental finding, consider Tamoxifen

Lobular Carcinoma In Situ

  • Usually incidental finding at biopsy
  • Younger premenopausal women
  • 1% risk of breast cancer per year
  • The future cancer can appear in either breast
  • If surgery is to be considered, the procedure of choice is bilateral mastectomy
  • Tamoxifen can reduce future risk of breast cancer by 50%

Increased probability of developing a carcinoma of the breast

  • This can happen in 20-30 years after diagnosis of LCIS (Lobular carcinoma in situ)
  • 1% risk increase of breast cancer per year in someone diagnosed with LCIS
  • No role for sentinel lymph node biopsy.
  • Treatment for Lobular Carcinoma In Situ (LCIS)
  • Close observation
  • Consider repeat mammogram in 6 months.
  • Informed of increased risk of breast cancer
  • No role for re-excision, SLN or irradiation.
  • Tamoxifen should be considered with a nearly 50% reduction in cancer formation in women with LCIS
  • For patients who insist on a surgical operation – a bilateral total mastectomy would be the procedure of choice because the risk of breast cancer is equal on both sides.
Tamoxifen mechanism of action.  Breast Cancer.
Tamoxifen mechanism