The term ‘breast adenocarcinoma’ is an over-arching term used for breast cancers.
Adenocarcinoma refers to a type of cancer that begins in the glandular tissue cells that have a secretory function.
Both the breast ducts and lobules contain a lot of glandular tissue. Therefore, many breast cancers that start in the breast ducts or lobules fall under the category of adenocarcinomas.
Lobes, Lobules and Ducts
Each breast typically has around 15 to 20 sections called lobes and many smaller sections called lobules. The lobules produce breast milk. The breast milk is secreted into the breast ducts and then carried towards the nipple.
Most breast cancers start in either the breast ducts or the lobules. For this reason, both ductal and lobular breast cancers are referred to as breast adenocarcinomas.
The earliest forms of breast cancer are ductal carcinoma in-situ (DCIS) and lobular carcinoma in-situ (LCIS). In DCIS, the abnormal cells are present but still contained in the milk ducts. Likewise, with LCIS the abnormal cells are found in the breast lobules but have not yet spread to surrounding tissues.
Hence, the term ‘in-situ’ means that the abnormal cells are ‘in the same place’ or have not spread yet. The prognosis for both DCIS and LCIS is excellent.
The two main types of adenoma-carcinoma are:-
- Invasive ductal carcinoma (sometimes called infiltrating ductal carcinoma
- Invasive lobular carcinoma (sometimes called infiltrating lobular carcinoma)
1) Lobular adenocarcinoma
Lobular carcinomas are actually less common than ductal carcinomas accounting for around 10% to 15% of breast cancers.
However lobular carcinomas tend to have a better prognosis than ductal carcinomas. Lobular breast cancer has a 5-year survival rate of 77% to 93% with an average of around 90%.
2) Invasive Ductal Carcinoma
Around 80% of breast cancers are the infiltrating ductal carcinoma variety of adenocarcinoma.
However, there are also a number or rarer, specialized forms of adenocarcinoma. The subset of cancers listed below account for no more than 6% of all breast cancers.
- Inflammatory breast cancer accounts for between 1% and 6% of all breast carcinomas.
- Medullary breast carcinoma accounts for 3% to 5% of breast cancers.
- Mucinous breast carcinoma accounts for about 3% of breast cancers.
- Tubular breast carcinoma accounts for only 1% to 2% of all breast cancers.
- Cribriform breast carcinoma accounts for 5% to 6% of all breast cancers.
- Papillary breast carcinoma accounts for between 1% to 2% of all breast cancers.
Note: Because lobular invasive cancer is quite rare, some medical specialists argue that it should be included in the above sub-group. There are, of course, many other subtle variations and hybrid presentations of this core group of specialized adenocarcinomas.
Immunochemical stains can determine if suspected breast cancer is Adenocarcinoma
The microscopic examination of a breast biopsy specimen usually involves the staining of a cell sample to determine the presence of various proteins or hormones.
Analysis of the immunohistochemistry staining process can greatly assist in the differential diagnosis of breast cancers. Furthermore, the staining process can help determine the feasibility of adjuvant chemotherapy treatment.
For example, around 72% of breast adenocarcinomas overexpress the H19 gene as compared to healthy tissues. Notably, normal breast tissue does not express H19 RNA in the mammary glands, except during puberty and pregnancy.
Hormonal receptors for estrogen (ER+) and progesterone (PR+), the Wilms tumor susceptibility gene 1 (WT1) and gross cystic disease fluid protein (GCDFP) are also useful for the diagnosis of breast adenocarcinoma.
Handy Questions & Answers
What are the treatments for invasive breast adenocarcinoma?
Treatment for invasive breast adenocarcinoma may include:-
- Breast surgery: either a lumpectomy to remove the tumor or a mastectomy
- Radiation Therapy
- Hormonal medication
- Targeted Therapy
What are the two main types of adenocarcinoma?
The two most common types of breast cancer are ductal carcinomas and lobular carcinoma.
What are the symptoms of invasive ductal carcinoma?
What are the symptoms of lobular carcinoma?
Often, in the earliest stages, lobular carcinoma causes no signs or symptoms. Lobular invasive breast cancer may cause an area of thickening in the breast. Likewise, there may be an area of ‘fullness’ or swelling in the breast.
The appearance of the skin over the affected breast may change and appear dimpled. The nipple can become inverted.
Please note, however, that lobular breast cancer is less likely than other types to cause a firm breast lump.
- Adriaenssens E, Dumont L, Lottin S, Bolle D, Leprtre A, Delobelle A, Bouali F, Dugimont T, Coll J, Curgy JJ. (1998) H19 overexpression in breast adenocarcinoma stromal cells is associated with tumor values and steroid receptor status but independent of p53 and Ki-67 expression. Am J Pathol. 1998 Nov;153(5):1597-607. https://www.ncbi.nlm.nih.gov/pubmed/9811352
- Caylor H. Bilateral Adenocarcinoma of the Breast. Annals of Surgery ( April 1929) – Volume 89 – Issue 4 – p 549-551