Should low-risk patients be treated with three-dimensional conformal radiation therapy-accelerated partial-breast irradiation in an off-protocol setting?

Abstract

A 52-year-old business executive presents 3 weeks after lumpectomy to discuss radiation therapy for her mammo-graphically detected stage I (pT1c, pN0, M0) left-sided breast cancer (Figs 1A and 1B). Her medical/surgical history is significant only for left-breast hypoplasia/asymmetry (one cup size smaller) since puberty, for which she ultimately underwent a right breast reduction 12 years ago. Pathology (Fig 1C) from her recent lumpectomy/sentinel node biopsy revealed a 1.1-cm invasive ductal carcinoma, Nottingham grade 1 to 2, nuclear grade 1, estrogen (ER) and progesterone receptor (PR) positive (ER, 90%; PR, 90%), and human epidermal growth factor receptor 2-neu negative by immuno-histochemistry, with margins >4 mm and no lymph vascular space/perineural invasion or sentinel node involvement. On the basis of these pathologic features and a 21-gene recurrence score of 10, the oncologist recommends adjuvant endocrine therapy with an aromatase inhibitor after irradiation. During the course of the consultation, it becomes clear that the patient has an unfounded adversity toward radiation therapy. Furthermore, she indicates that she has an important international business trip scheduled in 3 weeks that she must attend and repeatedly expresses concerns about her ultimate cosmetic outcome, stating that she is unmarried and actively dating. On examination, there is a right-sided, well-healed inframammary breast reduction scar, a left-sided healing periareolar lumpectomy scar, and an axillary sentinel node biopsy scar (Fig 1D); the breasts are bilaterally symmetric, with an excellent cosmetic result based on the Harvard cosmesis scale.1 The patient wishes to discuss the fastest radiation delivery options so that she may resume work. The irradiation facility only offers external beam radiation therapy.