Breast cancer and pregnancy: diagnosis and treatment options

A 36-year-old woman had noticed a lump in her right breast, just after she had discovered she had been pregnant for about 6 weeks. At referral to our clinic, on physical examination a palpable mass was found in the upper quadrant of her right breast, sized 2 cm in diameter. Diagnostic mammography and ultrasound were performed elsewhere and showed an uncertain density on mammography and an uncertain hypoechoic structure on ultrasound cranial to the righter mammilla, sized 15 mm in diameter. Utrasound of the axilla showed no suspected lymph nodes. A core biopsy proved an adenocarcinoma. After discussing the different options, the patient preferred a skin-sparing mastectomy with nipple banking and sentinel node biopsy. The sentinel node was retrieved by 85 MBq technetium-99m nanocolloid intra-tumoural injection, without using blue dye. At histopathology the tumour was T1 (15 mm) in size, B&R grade II; the sentinel node was tumournegative after multiple slicing and IHC staining with Cam 5.2; oestrogen receptor was 100% positive and progestin receptor was 100% positive; HER2neu was negative. The margins were free. The Mammaprint showed a low-risk signature, that is no distant metastases within at least 5 years. Since the patient was in her first trimester of pregnancy, and the child was very much desired, finally, the patient opted for endocrine therapy. She will receive tamoxifen and ovarian suppression by LHRH agonist after her child delivery. She decided not to have adjuvant chemotherapy, particularly considering the high hormone responsiveness of the tumour and the Mammaprint low risk. In addition, due to her young age, she was referred to the genetic counselling department.