New study reveals late recurrence and low survival rate of adenoid cystic carcinoma of the breast
RESEARCH SPOTLIGHT: New study reveals late recurrence and low survival rate of adenoid cystic carcinoma of the breast and the need for tailored treatment plans
What is adenoid cystic carcinoma (ACC)?
Adenoid cystic carcinoma (ACC) is a rare type of cancer that most commonly affects the salivary glands—about 1 in 10 salivary gland cancers (SGCs) are ACCs. While ACC primarily affects the salivary glands, it can also occur in the nasopharynx, trachea, cervix, skin, lungs, kidneys, and, extremely rarely, in the breast. Less than 1% of all breast cancers are ACCs [1].
Misdiagnosis of ACC of the breast
While ACC of the breast is slow-growing and treatable, it can be easily misdiagnosed as other forms of more aggressive breast cancer due to its status as a triple-negative breast cancer (TNBC). Most breast cancer tissues have at least one of three receptors: the oestrogen receptor (ER), progesterone receptor (PR), or human epidermal growth factor receptor 2 (HER2). These receptors pass signals to cancer cells to stimulate growth. Many breast cancer treatments therefore target these receptors to prevent, slow, or stop cancer growth.
TNBCs lack these receptors, so alternative treatment strategies are needed. TNBC accounts for around 15% of all breast cancers, and tends to be aggressive, likely to spread beyond the breast, and less responsive to treatment than other breast cancers [2,3]. However, ACC of the breast, despite often being classed as a TNBC, has a favourable prognosis and a high survival rate. This makes ACC of the breast an exception among other TNBCs.
Distinguishing ACC of the breast from other TNBCs early on can ensure that ACC specific treatment options are explored. Imaging is a crucial tool for spotting breast cancers early, but because ACC is so rare and there is a lack of imaging studies defining its characteristics, its features aren’t well understood. This makes it easy to mistake ACC for other types of triple-negative breast cancer (TNBC), which can lead to less effective or inappropriate treatment plans [4]. A lab method called immunohistochemistry, which uses antibodies to test tissues, has shown to be helpful in identifying ACC of the breast and setting it apart from other tumors with similar features [5].
A new study
A recent study by Britton et al (2025) looked at how ACC of the breast progresses and compares to other types of ACC. They analysed data from 450 ACC patients (16 of whom had ACC of the breast) diagnosed between 1990 and 2020. The researchers retrospectively reviewed disease characteristics, treatment, and survival outcomes.
Key findings
- Patients with ACC of the breast were treated with a combination of surgery, chemotherapy, and radiotherapy, consistent with the standard management of other breast cancers.
- Initial survival rates for patients with ACC of the breast were high—100% at two years and 87.5% at five years.
- The cancer recurred in 7 of the 16 ACC of the breast patients, with the median time to recurrence being 6 years. Once the cancer recurred, the median survival rate dropped dramatically to only 9 months, significantly lower than other ACC patients who had a median post-recurrence survival rate of 4.25 years.
- 6 out of the 7 patients with recurrent ACC of the breast died from their disease. This shows that, while ACC of the breast has a similar overall survival rate to other ACCs, the survival rate after recurrence is much lower.
This study highlights that ACC of the breast behaves differently from other ACCs, so its management should reflect this. ACC of the breast typically recurs more than 5 years after diagnosis, and the post-recurrence survival rate is low. Clinicians should therefore plan for longer-term monitoring to catch these late recurrences.
Unfortunately, research is still limited because this type of cancer is so rare. It is important for both clinicians and patients to be aware of this rare type of breast cancer to ensure it can be accurately diagnosed and ACC specific management can be considered.
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References
- Kocaay, A.F., Celik, S.U., Hesimov, I., Eker, T., Percinel, S. and Demirer, S., 2016. Adenoid cystic carcinoma of the breast: a clinical case report. Medical Archives, 70(5), pp.392-394.
- Gordillo, C. and Chukus, A., 2022. Adenoid cystic carcinoma: A case of rare breast cancer. Radiology Case Reports, 17(3), pp.690-692.
- Kumar, P. and Aggarwal, R., 2016. An overview of triple-negative breast cancer. Archives of gynecology and obstetrics, 293, pp.247-269.
- Zhang, W., Fang, Y., Zhang, Z. and Wang, J., 2021. Management of adenoid cystic carcinoma of the breast: a single-institution study. Frontiers in oncology, 11, p.621012.
- Gillie, B., Kmeid, M., Asarian, A. and Xiao, P., 2020. Adenoid cystic carcinoma of the breast with distant metastasis to the liver and spleen: a case report. Journal of Surgical Case Reports, 2020(11), rjaa483.