Introduction: To avoid unnecessary mastectomies and reoperations a correct size assessment of malignant lesions in breast is required. Sometimes a supplementary MRI is therefore recommended. However, at our unit MRI is not easily available. Contrast enhanced spectral mammography (CESM) has in smaller studies been shown to be equal to MRI regarding sensitivity and specificity. Size assessment using contrast-based modalities as CESM has also been shown to be significantly more accurate than using mammography. Prospective randomized studies using CESM are lacking.

Aim: The aim of the study is to evaluate the added value of CESM in diagnostics of breast cancer and choice of operation; partial mastectomy or mastectomy.

A pilot study of 50 patients will be conducted to prepare for a larger prospective randomized study.

Method: Patients found with breast cancer after diagnostics with mammography, ultrasound and core biopsy, and whom are recommended primary surgery, will be enrolled in the study. A supplementary examination with CESM will be performed. Preoperative extent of the malignant lesions are estimated with each modality and is later compared with the extent measured in post-operative PAD. Data on weight, length, age at menopaus, use of contraceptive pills, HRT or endocrine therapy, breast volume and density is collected, as well as data of diagnosis (ductal or lobular carcinoma), surrounding DCIS, histological grade, ER, PgR, Her2 expression and Ki67 index.

In this pilot study sensitivity and specificity for each modality is calculated. Multivariate analysis will be performed regarding influential factors. Pearson correlation coefficient will be calculated for each modality regarding size assessment of the malignant lesions in comparison with definitive PAD.

Inclusion Criteria:

• Patients diagnosed with breast cancer and whom are planned for primary surgery
• Signed informed consent

Exclusion Criteria:

• Ongoing pregnancy
• Ongoing lactation
• Allergy against iodine contrast
• Treatment with metformin (against diabetes)
• Renal failure
• Hyperthyroidism
• Severe heart condition
• Myasthenia gravis
• Implants
• Inability to understand study information

Most breast cancers occur in women. Male breast parenchyma is very small. Not suitable to examine by contrast enhanced spectral mammography in this study