What is the Most Aggressive Type of Breast Cancer?

Invasive breast cancer is more aggressive than localized breast cancer because invasive breast cancer has spread beyond breast tissue. Triple negative breast cancer is breast cancer without estrogen or progesterone receptors and without overproduction of Her2, making it both agressive and difficult to treat. Triple negative breast cancers grow faster and have less treatment options. Triple negative breast cancer is also more likely to recur, meaning it can come back after it has been treated. The most common invasive breast cancers are invasive ductal carcinoma (IDC) and invasive lobular carcinoma.

Reference:

Cancer: https://www.cancer.org/cancer/breast-cancer/understanding-a-breast-cancer-diagnosis/types-of-breast-cancer/triple-negative.html

NBC: https://www.nationalbreastcancer.org/triple-negative-breast-cancer

Komen: https://ww5.komen.org/AboutBreastCancer/FactsandStatistics/WhatisBreastCancer/InvasiveBreastCancers.html