Appearance of tumour cells along the needle track in patients with breast cancer diagnosed by SURECUT needle biopsy is found in two out of 47 consecutive cases. It is not known whether these cells are early implantation metastases or are harmless. To avoid any unnecessary risk to the patients, we recommend that needle biopsy is so performed, that it is possible to remove the track during the definite surgical procedure, and that penetration into the muscles of the thoracic wall during the biopsy procedure is avoided.