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VERIFIED CONTENTAuthor: Krzysztof Bialazite

Lobular carcinoma of the breast is one of the subtypes of breast cancer. It is estimated that lobular carcinoma accounts for about 10-15 percent. malignant breast cancer. Find out the special features of breast lobular cancer, the types of breast lobular cancer, the symptoms of breast lobular cancer, and how to diagnose and treat breast lobular cancer.

Lobular carcinoma of the breastis a subtype of breast cancer distinguished on the basis of the microscopic structure of this neoplasm.

Breast cancer is no longer seen as a single disease in modern medicine. Currently, it is a group of diseases whose common feature is the place of their origin - the mammary gland. Many years of research into breast cancer have allowed this group of diseases to be divided into categories.

The individual types of breast cancer differ in terms of biological features, course and, consequently, response to treatment and prognosis. Lobular breast cancer has many features in common with other breast cancers. However, there are some differences that are unique to lobular carcinoma; they may influence a slightly different course of diagnosis and treatment of this neoplasm.

Lobular carcinoma of the breast - characteristic features

The full name of lobular breast cancer is:invasive lobular carcinoma of the breast . It is the second most common malignant neoplasm of the mammary glands; it accounts for about 10-15% of all breast cancers.

  • What are lobules?

There are 2 dominant types of tissue in the mammary gland: adipose tissue and glandular tissue. Their mutual proportion changes depending on a woman's age, body weight and hormonal status.

The glandular tissue of the breast is organized into special subunits called lobules. Lobular cells are capable of producing secretions from the mammary glands - milk.

Each lobule is connected to a discharge conduit, which enables the transport of secretions produced in it. The milk formed in the lobules, thanks to the duct system, flows out of the nipple.

Due to the important role in neoplastic processes, a certain type is distinguished in the structure of the breastspecific structure. It is the so-called terminal ductal lobular unit (TDLU).

Many breast neoplastic lesions (both benign and malignant) begin to develop within this unit. The TDLU consists of a lobule with an intra- and extralobular duct. As you can easily guess, this unit is also the site of the formation of lobular breast cancer.

Invasive ductal carcinoma occurs much more frequently in the breast. In addition to the incidence, there are many important differences between the two breast cancers.

Lobular breast cancer grows in a characteristic way : it does not form a compact mass, but forms narrow, streaked infiltrates. This causes great difficulties in its imaging: standard imaging tests (e.g. mammography) do not always give a chance to visualize lobular breast cancer.

Another consequence of such an overgrowth is a relatively long asymptomatic period of its development - the first symptoms of the disease may appear only at the stage of its advanced advancement.

Another characteristic feature of breast lobular cancer is its tendency to form multiple tumor foci at the same time. Lobular carcinoma is also associated with a slightly higher risk of cancer in the other breast.

We call this situation contralateral breast cancer. The diagnosis of lobular cancer of one breast gland always requires a thorough examination of the other breast.

Each case of lobular cancer of the breast requires detailed research, called molecular diagnostics. These are tests that allow to determine the individual characteristics of a given tumor and assess the chance of responding to various types of therapy.

Most lobular breast carcinomas show less aggressive behavior in relation to ductal carcinoma in these studies.

Lobular carcinoma of the breast is in most cases hormone-dependent; his cells often have, among others estrogen receptors, which enables the use of hormone therapy.

Lobular carcinoma of the breast - risk factors

Factors that increase the risk of developing breast cancer are common to all types of breast cancer. These include:

  • female - 99 percent of breast cancer cases occur in women
  • age - the risk of developing breast cancer increases with age
  • hormonal factors - most cases of lobular cancer of the breast show the so-called hormone dependence

Hormonal conditions influencing the development of breast cancer may not be modified(patient-independent): Examples include prolonged exposure to estrogen caused by the early onset of menstruation or the late onset of menopause. An example of a modifiable effect on the endocrine system is the use of hormone replacement therapy by peri and postmenopausal women. Hormone replacement therapy may increase the risk of developing breast cancer, and there are also reports linking an increased incidence of lobular breast cancer in the last 20 years with an increase in the use of hormone replacement therapy during this period.

  • genetic factors - the incidence of breast cancer may be related to a genetic predisposition. The best known mutations that increase the risk of breast cancer are the BRCA1 and BRCA2 mutations.

The presence of cases of breast cancer in the immediate family (mother, sister) also increases the risk of developing this cancer.

  • Lifestyle factors - Obesity, inadequate physical activity and alcohol consumption are believed to increase the risk of developing breast cancer.
  • factors associated with the presence of specific changes in the breasts - the recognition of certain types of changes in the mammary glands is a risk factor for the development of breast cancer.

An example of such a change is Lobular Carcinoma In Situ (LCIS), which increases the risk of invasive breast cancer by about 8 times.

Lobular carcinoma of the breast - precursor changes

Invasive lobular carcinoma of the breast is a malignant tumor that develops within the lobules of the mammary glands.

The invasive nature of cancer causes its cells to invade surrounding tissues, and in the later stages of the disease - to form metastases in lymph nodes and distant organs.

The lobules of the mammary glands may also develop proliferative changes other than invasive lobular carcinoma. Among them we distinguish:

  • ALH - Atypical Lobular Neoplasia
  • LCIS - Lobular Carcinoma in Situ.

These are lesions made up of atypical, abnormal cells which, unlike invasive cancer, are found only within lobules and do not tend to invade other tissues.

Since ALH and LCIS lesions are very similar to each other, the distinction between them depends only on the number of abnormal cells. Atypical lobular hyperplasia is diagnosed when abnormal cells account for less than 50 percent.lobule volumes; Lobular carcinoma in situ means an involvement of more than 50%. its volume.

Both ALH and LCIS increase the risk of developing breast cancer. Interestingly, it does not have to be lobular carcinoma - research has also shown an increased risk of developing other malignant breast cancers, including ductal carcinoma.

Atypical lobular hyperplasia and lobular carcinoma in situ are considered to be the so-called non-obligatory precursors of breast cancer. This means that these changes may or may not lead to the development of invasive breast cancer.

Most cases of ALH and LCIS are detected by chance during a breast biopsy. At this point, it is worth emphasizing once again that these changes are not cancer, but only increase the risk of invasive cancer.

It is estimated that ALH causes an approx. 4-fold and LCIS approx. 8-fold increase in the risk of developing invasive breast cancer. For this reason, for many years people wondered what should be the right procedure after detecting this type of change.

Currently, the diagnosis of ALH or LCIS is an indication for regular preventive examinations and observation of patients. The exceptions are patients with additional burdens (e.g. having genetic mutations increasing the risk of breast cancer) or the presence of more aggressive forms of LCIS.

In such cases, prophylactic surgical interventions (excision of lesions, less often prophylactic mastectomy) are considered more often.

Lobular carcinoma of the breast - classifications

The diagnosis of invasive lobular carcinoma of the breast requires thorough research. Their purpose is to determine the microscopic structure, stage and biological features of the neoplasm.

The above data constitute an important prognostic factor and allow for the selection of the most optimal therapy. Pathologists examine the tumor tissue. The result of the pathomorphological examination usually includes the following data:

a. The histological structure of the tumor.While viewing the preparation of the lobular carcinoma of the breast under a microscope, the pathologist assesses the position of the neoplastic cells. On this basis, histological subtypes of lobular carcinoma of the breast are distinguished.

The most common variant of breast lobular cancer is the classic subtype, in which the tumor cells spread along the so-called breast stroma (bands of adipose tissue and connective tissue) in the form of strips made of single cells.

In the solid type of lobular carcinoma of the breast, the tumor cells form large clusters, and in the follicular type - slightly smaller, resemblingbubbles.

The tubulo-lobular type means that some of the cells are arranged as in the classic variant of cancer, and some of them form coil-like structures.

If it is difficult to identify the dominant pattern of neoplastic cells, the histological type of lobular carcinoma is mixed.

b. Histological grade - gradingAnother element of the pathomorphological assessment of lobular breast cancer is the so-called grading, i.e. the assessment of the degree of histological malignancy.

It is performed by assessing the tumor cells in terms of their malignancy. There are special cell structure parameters (e.g. the appearance of cell nuclei, the presence of cell division structures) that allow this classification to be made.

The grading scale has three grades (G1, G2, G3), with G1 being the lowest grade and G3 the highest grade. The vast majority of classic lobular carcinomas of the breast are graded G1 or G2.

c. Clinical advancement - stagingClinical advancement is assessed in the TNM classification, which is used to assess the advancement of many types of malignant neoplasms.

This classification takes into account 3 parameters of the tumor: the size of the primary tumor (T - Tumour), the presence of metastases in the lymph nodes (N-Nodes) and the presence of metastases in distant organs (M-Metastases). For breast cancer, the symbols used in the TNM classification have the following meanings:

  • T1 - primary tumor size<20mm,
  • T2 - primary tumor size between 20 and 50mm,
  • T3 - primary tumor size>50 mm,
  • T4 - primary tumor infiltrating the chest and skin wall,
  • N0 - no metastases to nearby lymph nodes,
  • N1 - presence of metastases in 1-3 local lymph nodes,
  • N2 - presence of metastases in 4-9 local lymph nodes,
  • N3 - presence of metastases in 10 or more nearby lymph nodes (or involvement of distant lymph nodes),
  • M0 - no metastases to distant organs,
  • M1 - presence of metastases to distant organs.

d. Molecular tumor assessmentThe final stage in the pathomorphological assessment of lobular cancer of the breast is molecular diagnostics.

This test allows you to learn about the biological characteristics of the cancer and is a very important guide in choosing the right therapy. The first stage of this diagnosis is the assessment of molecular markers, which include estrogen receptors, progesterone receptors and the HER2 marker.

A positive result of one of them isan indication for the use of targeted therapy directed specifically against this factor (e.g. anti-estrogen therapy in the presence of estrogen receptors, anti / HER2 therapy in the event of a positive HER2 result).

On the basis of molecular studies, 4 subtypes of breast cancer are distinguished: luminal A and B, HER2-positive and basal type. Most lobular carcinomas fall into the first three categories. The basal type, associated with the highest aggressiveness and worst prognosis, is extremely rare in lobular breast cancer.

Lobular carcinoma of the breast - symptoms

Lobular carcinoma of the breast tends to infiltrate the stroma of the breast glands in the form of narrow bands.

This type of cancer rarely forms compact structures. For this reason, symptoms of lobular breast cancer are not very specific.

There is rarely a lump when palpating the breasts. Symptoms more typical of lobular cancer of the breast are a change in texture, thickening or swelling in the breast gland.

It is also worth taking a close look at the skin on the breasts for changes in its structure and color. Another symptom of breast lobular cancer is that the nipple is retracted, its shape changes, or abnormal discharge appears.

Lobular carcinoma of the breast - diagnosis

Diagnostics of lobular cancer of the breast begins with a medical interview and physical examination. When talking to your doctor, expect questions about the factors that increase your risk of developing breast cancer (use of hormone replacement therapy, a family history of breast cancer).

A physical examination of the mammary glands in lobular cancer does not have to show any abnormalities; perceptible changes in the breasts may not appear until the late stages of the disease.

The next stage in the diagnosis of lobular cancer of the breast is imaging. The basic test for breast cancer is mammography. Unfortunately, in the case of lobular carcinoma, mammography does not always show the tumor foci.

The reason for this is the way the lobular carcinoma grows (thin, narrow bands) and the slight differences between the neoplastic tissue and the tissue of a he althy breast.

The sensitivity of mammography in detecting lobular cancer of the breast is estimated at 55-80 percent. (depending on sources). This means that the diagnosis of this type of cancer often requires additional imaging tests.

The second commonly used imaging test is the ultrasound examination (USG). It is a toolallowing for a better assessment of the mammary glands in which glandular tissue predominates (this is the case, for example, in younger patients).

Ultrasound examination in the case of lobular breast cancer is not, like mammography, an ideal examination. The sensitivity of ultrasound in the diagnosis of lobular cancer ranges from 60 to 90%.

The imaging examination with the highest sensitivity (according to research 93%) is the magnetic resonance imaging of the breast. Magnetic resonance imaging allows for an accurate assessment of the size of the tumor, which is usually not possible with imaging studies of lower resolution.

The main disadvantage of MRI is its high price compared to mammography and ultrasound. During imaging diagnostics of lobular carcinoma of the breast, one should always bear in mind the tendency of this neoplasm to form many foci at the same time.

For this reason, the detection of one tumor is always an indication for a thorough examination of both breast glands.

In order to establish the diagnosis of lobular carcinoma of the breast, it is necessary to perform a pathomorphological examination of the tumor tissue. Its fragments are obtained during an aspiration biopsy. It is a test that involves taking tissue samples from a place suspected of developing a neoplastic process.

In addition to establishing the diagnosis, the pathomorphological examination of the tumor tissue allows for the assessment of its biological features, which is crucial for establishing a treatment strategy.

Lobular carcinoma of the breast - treatment

In the treatment of lobular cancer of the breast, methods are used that are used in all types of malignant breast cancer. The treatment method is selected individually each time.

The therapeutic strategy depends on the type of cancer and its stage. The mainstay of treatment for lobular cancer of the breast is surgery in most cases.

In some cases, pre-surgery treatments include radiotherapy, hormone therapy or chemotherapy (the so-called neoadjuvant therapy). Their goal is to reduce the tumor mass and remove microscopic foci of neoplastic spread (so-called micrometastases).

The type and extent of surgery in lobular breast cancer depends on the size of the tumor. In the case of relatively small lesions, conserving procedures are performed, such as lumpectomy (removal of the tumor itself with a margin of he althy tissue) or quadrantectomy (removal of one of the four quadrants of the breast).

For more advanced cancers, a mastectomy (removal of the entire breast) may be necessary. It is worth mentioning that nowadays, after mastectomy, it is very often performedthere are reconstructive procedures of the mammary glands.

During surgery, in addition to removing the tumor tissue, it may also be advisable to remove the surrounding lymph nodes. The number of lymph nodes necessary for removal is determined on the basis of their pathomorphological examination.

The so-called sentinel node, i.e. the lymph node that first collects lymph from the tumor area. If pathological examination reveals the presence of neoplastic cells in the sentinel node, it is usually necessary to remove more lymph nodes.

After surgical treatment of lobular cancer of the breast, complementary methods are often used, collectively known as adjuvant therapy. The type of therapy depends on the type of tumor and its sensitivity to various treatment methods.

If the tumor is hormone-dependent (e.g. the presence of estrogen receptors), supplementary hormone therapy is used. This is very common in breast lobular cancer.

If the molecular diagnosis of lobular cancer of the breast shows the HER2 + feature, targeted anti-HER2 treatment (Trastuzumab drug) is initiated. Additionally, depending on the indications, it is possible to use various types of chemotherapy and radiotherapy.

Lobular carcinoma of the breast - prognosis

The prognosis in lobular breast cancer depends - as in most malignant neoplasms - on the stage of the disease at diagnosis. Most of the lobular carcinoma of the breast shows features of limited aggressiveness and histological malignancy.

This type of cancer relatively often has positive estrogen receptors, which makes it sensitive to hormone therapy.

On the other hand, the specific growth pattern of this tumor results in a relatively long asymptomatic period and difficulties in visualization in standard imaging tests.

For this reason, lobular cancer of the breast is sometimes detected only at a higher stage of advancement. The earlier you manage to diagnose and start treatment for lobular breast cancer, the greater the chance of a full recovery and recovery.

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Category:

Oncology