Spontaneous regression of breast cancer with immune response: a case report

Abstract

Background Spontaneous regression (SR) is a rare phenomenon in which a cancer disappears or remits without treatment. We report a case of breast cancer that showed spontaneous tumor regression in the surgical specimen after core needle biopsy. Case presentation A 59-year-old woman came to our hospital complaining of a painful lump in the right breast. In the upper-outer quadrant of the right breast, a tumor with an unclear boundary, 30 mm in diameter, was palpable. In pathological findings from needle biopsy, the tumor was diagnosed as solid-type invasive ductal breast carcinoma. Partial coagulation necrosis was generated in estrogen receptor-negative, HER2-negative, and AE1/AE3-positive ductal carcinoma without infiltration of lymphocytes. Surgery for right breast cancer was then performed. Histological examination of the surgical specimen revealed the tumor was invasive ductal carcinoma with lymphocyte infiltration, coagulation necrosis, and fibrous tissue with hemosiderin. The tumor formed a solid nest, 3 mm in diameter, suggesting the possibility of SR. Conclusions Immune responses, infection, hormones, surgical stress, and ischemia have been reported as mechanisms of SR. The findings in this case strongly suggest that SR of breast cancer is associated with anti-tumor immune responses.

What Can Trigger Spontaneous Regression of Breast Cancer?

“…A thorough search in PubMed was performed in order to find all cases of epithelial BC–SR published so far (December 2022). Twenty-nine reported cases were found [ 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 ]. The results of our literature search are summarized in Table 1 .…”

“…The frequency of SR varies based on the type of cancer, occurring at a rate of about 1 out of every 60,000 to 100,000 cases of all cancers [ 2 , 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 ]. The mechanisms of SR are not fully understood, but several putative mechanisms have been proposed, including inflammation, apoptosis, ischemia, and immunological responses [ 2 , 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 ]. Moreover, additional mechanisms suggested to explain the phenomenon of SR include epigenetic modifications, hormonal responses, oncogenes, tumor suppressors, cytokines, growth factors, and psychological factors [ 2 , 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 ].…”

“…In this regard, radiation therapy reduces the supply of blood and nutrients to the tumor, so necrosis and/or vascular insufficiency could slow tumor growth. In these cases, despite the fact that treatment is inadequate to cure the disease, the tumor is considered spontaneously regressed [ 2 , 6 , 13 ].…”

“…Although breast carcinoma is a common malignancy, cases of SR described in the literature are extremely rare [ 3 , 6 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 ]. Hundreds of tumor regressions published so far have been reviewed; however, to date, only twenty-nine cases of regressed epithelial breast cancer can be considered reliable [ 3 , 6 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 ]. We noticed that most of the patients were female in a wide age range.…”

“…Various authors have hypothesized that tumor regression may have been triggered by disparate mechanisms. In particular, both Cserni and Ohara assumed the role of metformin, an anti-diabetic, in SR [ 13 , 19 ]. The exact mechanism behind this “miraculous” phenomenon still remains poorly understood.…”