The phenomenon of spontaneous tumor regression in breast cancer

Spontaneous tumor regression is an increasingly prevalent phenomenon of partial or complete disappearance of primary tumor tissue or associated metastases in the absence of therapeutic intervention. Cases of spontaneous regression have been established in malignant tumors, such as testicular germ cell tumor, renal cell cancer, melanoma, basal cell carcinoma, neuroblastoma, colon cancer, breast cancer, as well as metastases. Breast cancer has increasingly been reported to have a higher rate of spontaneous regression than previously thought. Immunologic response is cited as the forefront of spontaneous regression phenomenon, with the focus on immunologic cell death. This report brings awareness to a case of spontaneous regression observed in invasive ductal carcinoma of the breast and how disruption of the tumor microenvironment can take a variable course even in malignant disease.