February 28, 2013

Today, we will be discussing breast cancer surgeries and breast setups for external beam radiation therapy.

• Radical mastectomy

1.      Removal of the breast with its overlying skin, all axillary lymph nodes, and the pectoral muscles.

2.      Overall long-term survival rate not improved, but chest wall recurrence reduced.

3.      Complication rate is high, and complications can be severe.

4.      Currently rarely performed.

• Modified radical mastectomy

1.      Modified to preserve muscle, some skin, lymphatics, and blood vessels improving cosmetic results, reducing arm swelling, and improving arm strength.

2.      Has replaced radical mastectomy.

• Lumpectomy

1.      Excisional biopsy that removes tumor with a margin of normal appearing tissue.

• Breast conservation therapy

1.      Equally effective for patients with early-stage breast cancer.

2.      Generally lower megavoltage beam energies (4-8MV) and tissue compensators are used to improve dose homogeneity.

3.      Tangential fields are used to encompass the entire breast and chest wall.

4.      The amount of lung projected at the center of the tangential fields should be limited to between 1.0-3.4cm, thereby reducing the risk of radiation pneumonitis.

5.      If peripheral lymphatic radiation is required, then overlapping or excessive gapping between fields must be avoided.

6.      Fields are treated daily with standard fractionation (180-200cGy/fraction) to a total dose of 4500-5000cGy.

7.      A boost dose may be delivered with a reduced photon field, electron beam, or interstitial technique, increasing the total dose to the primary tumor site to 6000-6600cGy.

• RT treatment techniques

1.      Tx for primary breast malignancy is one of the more technically challenging and relatively high-volume procedures.

2.      Techniques can vary by treatment center, but are only a variation on a theme or more standardized treatment.

• Positioning and immobilization

1.      Simulation must occur after patient’s arm mobility has returned enough to ensure proper positioning of the shoulder girdle.

2.      An important element in reproducibility in immobilization is the ability to index the patient to the immobilization device exactly the same way each day.

Reflections:

Surgery removing breast cancer with a margin of healthy tissue is very effective when paired with radiation therapy to eradicate any leftover cancer.  Also, breasts are not going to be in the same place if the torso isn’t inclined, therefore most breast patients must use a breast board to raise their heads and cause the breasts to sag down with gravity.  Gravity should help put the breasts near the same location everyday.  I am treating a very large woman at Nevada Cancer Center which uses only the wing board and vac-lock.  We are doing our best to get her in the same position everyday.  We are not using the breast board because she wouldn’t fit through the bore of the CT machine.

I decided to look up "breast cancer immobilization" and found a product called "bravelle".  It looks like it might be a plastic ring with three straps hooked to it to secure the breast in place.  Of course, in order to use it you would have to buy other immobilization products that work with the  bravelle.  From the pictures it looks to work well with both large and small breasts.  I haven't seen a bravelle here in Las Vegas.  We are, according to Jim, 10 years behind the country in medical technology.  Perhaps, it is used at other clinics elsewhere in the country.