What kind of radiation should you choose after lumpectomy for breast cancer?

Just a quarter of a century ago, almost all patients had mastectomy, even if their breast cancer is small.  But over the past few decades, it has been demonstrated that for small cancers, lumpectomy followed by radiation treatment is just as good as mastectomy, at preventing breast cancer recurrence.  Traditional proven radiation is external beam radiation directed to the entire involved breast for 6-7 weeks, 5 days a week (M Tu W Th F).  Depending on the size and extent of the cancer, radiation may include the chest wall and axilla (armpit) on the same side as the involved breast.  In some cases, the area treated may also include on the same side supraclavicular lymph nodes (nodes above the collarbone) and internal mammary lymph nodes (nodes beneath the breast bone near the center of the chest).

Recently, some patients with very early small cancers may consider Accelerated Partial Breast Irradiation (APBI).  Instead of treating the whole breast, APBI only delivers radiation to the focal location of the lumpectomy site.  This is because most recurrences occur at or near the site of previous cancer.  Currently, the most commonly used regimen involves only 5 days of radiation total.  A balloon is inserted into the lumpectomy site, in the office with local anesthesia.  On the fifth and final day of radiation, the balloon is pulled out.  The most established model Mammosite has been used in more than 35,000 women in the United States, and results with 4-year followup data have been good.  Despite its convenience, APBI is not for everybody.  Some general guidelines exist to determine who is "suitable" for APBI as of 2010.  As we gain more knowledge with longer use of this treatment modality, the guidelines may change in the future.  The "appropriate" criteria are: patient age 50 or more, unifocal (single) cancer, invasive cancer size no more than 2cm, pure DCIS (ductal carcinoma in situ) no more than 3cm, total tumor size (invasive and DCIS) no more than 3cm, margins clean of tumor, no lymphovascular invasion seen under microscope, and no cancer spread to lymph nodes.  Women with hereditary breast cancer, such as BRCA 1/2 carriers, should not consider APBI.

The above are only general guidelines.  Again, it should be emphasized that traditional whole breast radiation is an established treatment with much longer track record than APBI.  No two breast cancer patients are exactly alike, and therefore the decision making process is different and unique for each individual person.  Regardless of any one else's advice, you should make the choice that you personally will be able to live with for the rest of your life.