OFFICE NUMBER

305-271-3300

 

 

 

Radiation Therapy

Radiation therapy has been used to treat breast cancer for almost one century. It is part of the armamentarium against breast cancer and is considered an integral component in its management. Generally, it is easy to tolerate and safe. Radiation is included in the treatment plan based on its ability to reduce the risk of locoregional failure (tumor returning back in the breast or chest wall). It reduces local recurrence rates by approximately 70%.

How Does it Work?
It uses high-energy particles to destroy cancer cells. The radiation works by damaging the DNA of the cells. This genetic material is indispensable for cells to grow, multiply and ultimately survive. Normal cells that are in the radiation pathway are also damaged but to a lesser extent. They are better equipped to repair themselves and survive treatment.

 

Surgery and Radiation Therapy:
Surgery is considered the primary treatment of breast cancer. The goal of surgery is the removal of all cancer cells. Unfortunately, not even the most meticulous surgeon can guarantee complete removal of the cancer. Cancer cells are too small to be seen by the human eye. Breast imaging studies may not identify the location of all cancer cells prior to surgery. Cancerous cells can be left behind even in cases where we achieve negative margins (no cancer cells identified at the cut surface of the specimen removed). The cells that are left behind can grow and form a new tumor (recurrence). This is explained by the fact that some breast cancers are multifocal and multicentric. It is important to understand these terms.

 

Multifocal:
Multifocality refers to multiple foci of the same tumor in the same quadrant of the breast. Breast conservation could be a surgical treatment option as long as the tumor different tumor foci are close to the main tumor and can be resected through one surgical incision.

 

Multicentric:
Multicentricity refers to multiple tumors but at independent sites of origin in a separate duct system or a different quadrant of the breast. In other words, in some cases there are additional areas with microscopic cancer cells (think of these cells as salt and pepper) at a distance away from the known main tumor. Imagine a hurricane with the eye being the main tumor and the winds that surrounds the eye being these small independent cancerous cells. As a consequence, even if we remove the primary tumor there is the potential of leaving malignant cells behind. Numerous studies have shown that radiation therapy can kill these residual cells and significantly decrease the chances of a recurrence or development of a new tumor.

 

Breast Conservation

Role in Breast Conservation:
It is well established that lumpectomy with negative margins (removal of the tumor and a small cancer-free margin of tissue around the tumor) combined with radiation therapy provides the same long-term survival as does a mastectomy (removal of the entire breast). This applies to patients with either ductal carcinoma in situ or invasive carcinoma.

 

Mastectomy

Role After Mastectomy:
Radiation therapy is recommended in some patients treated with mastectomy. This is usually determined by the size of the tumor in the breast and the presence of either close or positive mastectomy margins.

 

Axillary Lymph Node Dissection

Role After Axillary Node Dissection:
Radiation therapy is also recommended in a group of patients after surgery. This is determined by the number of positive axillary nodes (lymph nodes under the arm that contain evidence of cancer) or the size of the tumor.

 

Radiation Therapy and Survival

Radiation therapy can improve long-term survival. The main effect of radiation therapy on local recurrence is seen during the first few years after treatment, but the primary effect on mortality is seen in later years. It has become apparent that effective local therapy is critical to maximizing long-term survival

 

Radiation Therapy Options

External Beam Radiation Therapy:
The first step is the planning session. The patient will be placed under a special X- ray machine named a simulator. The body will be placed in a position so the X- ray beam targets the area of interest, while sparing nearby healthy organs. The skin may be marked with special tattoos to assure the delivery of radiation to the same area. A mold may also be used to immobilized the body and keep it in the same position during treatment. Once the planning stage has been finalized the patient starts treatment.

Each radiation session lasts approximately 15 minutes. The entire visit to the radiation center will take approximately 1 hour. The patient generally gets treated everyday from Monday to Friday for 4 to 6 weeks.

 

External radiation therapy is an integral component in the treatment of breast cancer. The patient generally gets treated from Monday to Friday everyday for approximately 4 to 6 weeks.

 

Accelerated Partial Breast Irradiation (APBI):
Patient compliance with the recommended post-lumpectomy radiation therapy remains a clinical challenge. Although whole-breast radiation is proven to reduce local recurrences, it can represent a burden to some patients. The treatment takes up to 6 weeks to complete and requires daily trips to the radiation center. Some patients do not have the means for transportation and others do not have reasonable access to a radiation facility. Others are concerned about the potential effects on the surrounding healthy tissues and organs. Approximately 20% of patients who undergo breast conservation do not receive adjuvant radiation therapy to complete their treatment due to these conflicts. APBI is an alternative to a selective group of patients depending on the tumor characteristics and the age of the patient. A shorter course of radiation therapy (5 days) can alleviate some of the burdens of a longer course of treatment.

In women with early breast cancer treated with breast conservation, approximately 80% of local recurrences (tumor coming back in the breast) occur in the immediate vicinity of the lumpectomy cavity. The incidence of failure remote from the lumpectomy cavity is less than 5% and this number is unaltered by the addition of external radiation therapy. This suggests that APBI should be equivalent to whole-breast radiation therapy. APBI is still considered investigational and should be used in "low risk" patients. The American Society for Therapeutic Radiology and Oncology (ASTRO) and the American Society of Breast Surgeons (ASBS) have set patient selection guidelines. Several phase 3 clinical trials are being conducted to compare APBI to whole-breast radiation therapy. The final results are not available yet. The data available at this time is encouraging and has shown comparable local control as compared to whole-breast radiation therapy.

 

Accelerated partial breast irradiation is an alternative option to a selective group of breast cancer patients. The mammosite is a balloon catheter system use to deliver a shorter course of radiation therapy. The catheter is placed after lumpectomy as long as the margins are negative. The procedure is performed under sonographic guidance and local anesthesia.

 

The patient receives a short course of radiation therapy. The treatment is given twice a day for a total of five days. The catheter is removed as soon as the treatment is finished.

 

Available Partial-Breast Radiation Treatment Modalities Include:

  Balloon catheter systems (Mammosite)
  Insterstitial brachytherapy
  CT-based conformal external beam techniques
  Intraoperative electron beam therapy

 

Side Effects Balloon Brachytherapy:

  Fat necrosis
  Skin necrosis
  Infection
  Fibrosis
  Palpable mass
  Breast deformity
  Persistent seroma
  Pain

 

Side Effects of External Radiation Therapy:

  Skin desquamation
  Breast pain
  Fatigue
  Nausea
  Lack of appetite
  Breast swelling
  Lymphedema
  Rib fracture
  Pneumonitis
  Pulmonary fibrosis
  Cardiac disease (the risk appears to be associated with radiation methods)
  Radiation- induced sarcoma