What is the most common type of breast cancer?

• A. Invasive lobular carcinoma
• B. Infiltrating ductal carcinoma
• C. Medullary carcinoma
• D. Mucinous carcinoma

Answer: (B)

Infiltrating ductal carcinoma is recognized as the most common type of breast cancer, accounting for approximately 80% of all breast cancer diagnoses. This type of cancer begins in the milk ducts of the breast and invades surrounding tissues, which is a hallmark of its invasive nature. The significant prevalence of infiltrating ductal carcinoma can be attributed to the anatomical structure of the breast, as the ductal system is where the majority of breast cancers originate.

In contrast, the other types listed, such as invasive lobular carcinoma, medullary carcinoma, and mucinous carcinoma, are less common and have different characteristics and patterns of growth. Invasive lobular carcinoma accounts for about 10-15% of breast cancers and tends to grow in a less defined manner. Medullary and mucinous carcinomas are even rarer, making infiltrating ductal carcinoma the clear frontrunner in terms of incidence. This understanding helps in identifying the most prevalent form of breast cancer, facilitating awareness and treatment strategies in clinical practice.