Inclusion Criteria:

- treatment with BCT with SNB and/or ALND for primary breast cancer

- previous primary breast cancer located in the upper-outer quadrant of one breast

- Primary breast cancer treatment at least 3 years before the analysis, with or without
adjuvant chemo- or hormonal therapy.

Exclusion Criteria:

- breast surgery for other reasons than breast cancer

- recurrent breast cancer

- former allergic reaction to 99mTc-colloidal albumin.