Breast cancer arises when cells within the breast grow and multiply abnormally. This process can lead to the formation of a lump or mass of extra cells, called a tumor. In many cases the tumors are non-cancerous, or benign.

Cancer of the breast most frequently falls into one of two categories: ductal carcinoma (a cancer occurring in the milk ducts of the nipple) or lobular carcinoma (a cancer occurring in the milk-producing lobules of the breast). These tumors may be invasive, spreading quickly to other tissues such as lymph nodes, or in situ (noninvasive).

One in eight women will be diagnosed with breast cancer during her lifetime, but exams such as mammograms, breast MRI, breast ultrasound, and regular self-exams can help find the cancer early and improve the outlook for treatment. Breast cancer may be treated through surgery (lumpectomy or mastectomy), chemotherapy, radiation therapy, medication therapy (including targeted or biologic therapy, which targets specific changes in cells), or any combination of these treatments.

After consulting with your oncologist, they may conclude that radiation is the best next step. Radiation therapy is one of the most effective ways to destroy cancer cells in the breast that might remain after surgery. It uses a high-energy beam to damage cancer cells’ DNA, the material that causes the cells to divide. Following a lumpectomy, radiation is focused on the breast and sometimes the surrounding lymph node area to destroy any stray cells that may have been left behind. This treatment reduces the chance of a recurrence of cancer.

Radiation therapy is sometimes also given after a mastectomy, but only if there is a high risk of cancer recurring in that area. Our plastic surgeons and medical oncologists work together to offer an integrated program of post-mastectomy radiation to women who have undergone immediate reconstruction and require radiation treatment. Our approach has resulted in both excellent local control of the cancer and a low rate of major radiation-related problems with reconstruction.

The radiation treatment that will be used to treat you, will depend on the size and location of the tumor. At Weill-Cornell, we are exploring and using new technologies for treating breast cancer. Every case is treated with the utmost respect and care.

Side Effects

The side effects you may experience will depend on the area being treated, the type of radiation used and whether or not you also received chemotherapy. Before treatment, your doctor will describe what you can expect.

Some patients experience minor or no side effects and can continue their normal routines.

If at any time you develop side effects, tell your doctor or nurse. He or she can give you medicine to help.


Our physicians who specialize in the treatment of Breast Cancers:

Silvia Formenti, M.D.: (212) 746-3608

John Ng, M.D.: (212) 746-3614

Clinical Trials:

IRB # 1602017017 Accelerated Radiation Therapy (Art) To The Breast And Nodal Stations After Neo-Adjuvant Chemotherapy And Surgery: A Feasibility Study NCT02917421
Click Here 
This study is currently recruiting participants.

IRB # 1505016222 LY2157299 Monohydrate (LY2157299) and Radiotherapy in Metastatic Breast Cancer NCT02538471
Click Here 
This study is currently recruiting participants.

IRB # 1505016228 Phase I/II study of TLR7 agonist Imiquimod, Cyclophosphamide, and Radiotherapy in Breast Cancer Patients with Chest Wall Recurrence or Skin Metastases NCT01421017
Click Here  
This study is ongoing, but not recruiting participants.

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David H. Koch Center

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Stich Radiation Oncology Center

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Weill Cornell Medical Center
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Tel: (212) 746-3600
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The Arnold Center For Radiation Oncology

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Flushing, NY 11355
Tel: (718) 670-1501

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