From the Guidelines
Malignant breast masses are typically unilateral, meaning they occur in one breast rather than both breasts simultaneously. Approximately 95-98% of breast cancers present as unilateral disease at initial diagnosis, as stated in the acr appropriateness criteria1. This unilateral presentation occurs because most breast cancers arise from a single transformed cell that proliferates in one specific location within one breast. Some key characteristics of breast masses include:
- True breast masses are generally asymmetrical in relation to the other breast, distinct from the surrounding tissues, and 3-D
- A typical cancer may be firm, have indistinct borders, and have attachments to the skin or deep fascia with dimpling or nipple retraction, as noted in the acr appropriateness criteria1
- Benign masses typically are mobile and have discrete, well-defined margins and a soft or rubbery texture Bilateral breast cancers (occurring in both breasts simultaneously) are much less common, accounting for only about 2-5% of all breast cancer cases. When bilateral breast cancers do occur, they may represent either two separate primary tumors or metastasis from one breast to the other. The unilateral nature of most breast cancers is an important clinical feature that helps guide diagnostic workup and treatment planning, though it's essential to note that having cancer in one breast does increase the risk of developing a separate cancer in the opposite breast in the future, as discussed in the acr appropriateness criteria1.
From the Research
Malignant Breast Masses
- Malignant breast masses are typically unilateral, as most breast cancers originate in one breast 2.
- The study of diffuse unilateral MRI breast entities found that malignant entities, such as ductal carcinoma in situ, invasive ductal carcinoma, and invasive lobular carcinoma, often present with unilateral breast findings 2.
- While bilateral breast cancer can occur, it is less common than unilateral breast cancer 3, 4, 5.
- The diagnosis and treatment of breast cancer, whether unilateral or bilateral, require a multidisciplinary approach and consideration of various factors, including tumor load and molecular markers 3, 4, 5.
Diagnosis and Treatment
- The diagnosis of malignant breast masses often involves imaging techniques, such as MRI and ultrasound, as well as biopsy 2, 6.
- Ultrasound features, such as irregular shape, microlobulated or spiculated margins, and a width-to-anteroposterior dimension ratio of 1.4 or less, can help differentiate malignant from benign masses 6.
- Treatment options for breast cancer depend on the stage and type of cancer, as well as other factors, and may include surgery, radiation therapy, chemotherapy, and molecular treatments 3, 4, 5.