Micrometastasis

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A micrometastasis is a small collection of cancer cells that has been shed from the original tumor and spread to another part of the body through the lymphovascular system. [1] Micrometastases are too few in size and quantity to be picked up in a screening or diagnostic test, and therefore cannot be seen with imaging tests such as a mammogram, MRI, ultrasound, PET, or CT scans. These migrant cancer cells may group together to form a second tumor, which is so small that it can only be seen under a microscope. Approximately 90 per cent of people who die from cancer die from metastatic disease, since these cells are so challenging to detect. [2] It is important for these cancer cells to be treated immediately after discovery, in order to prevent the relapse (regrowth of the cancer) and the likely death of the patient.

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Detection of micrometastatic cells

The major concern with micrometastases is that the only way to determine if they are present in distant tissue is to remove cells from where they are located and look at slices of the tissue under the microscope. The typical biopsy procedure involves hematoxylin and eosin (H&E) staining of specific markers that correspond to the particular tumor type. [3] Although surgeons are able to remove parts of a single lymph node from the body to screen, it is impossible to remove every lymph node and other organs (lungs, liver, bones, etc.) to look for spread. [2] Doctors must assume that the tumor cells have likely spread to other regions of the body if micrometastases are present in one of the lymph nodes. The presence or absence of micrometastases is crucial in choosing the right treatment option for cancer patients.[ citation needed ]

The detection of micrometastases in the sentinel lymph nodes (SLN) is the primary indicator of its spread to the regional lymph nodes, bone marrow, peripheral blood and ultimately to distant metastatic sites, since they are the first of the nodes that cancer would travel to. [3] This concept applies to melanoma, breast cancer, and other solid tumors, including colorectal, esophageal, stomach, lung, head and neck, vulvar, and penile cancers. [3] Therefore, the presence of these cells in the SLN can help make predictions regarding the patient’s diagnosis and prognosis. For example, it has been found that the prognosis of women who have micrometastases to the sentinel lymph node is poorer than that of women who do not have any evidence of tumor in these lymph nodes. [2] The same applies to patients with melanoma and the other solid tumor cancers.[ citation needed ]

Before the micrometastases colonize at a distant site, the tumor cells can be found in the bone marrow or peripheral blood. [3] Tumor cells found in the bone marrow are known as disseminated tumor cells (DTCs), and those found in the peripheral blood are known as circulating tumor cells (CTCs). These cells have successfully left the primary tumor microenvironment and the SNLs, and are able to survive in a non-native environment, which makes them more aggressive. [3]

Treatment of micrometastases

In breast cancer patients, if micrometastases are present in the SLN, removal of these nodes is often the next step in treatment. Axillary lymph node dissection involves the excision of the nodes from the armpit, or axilla, region. Depending on the progression of the cells, the surgeon will determine the level of dissection that is required. Level one is the least invasive, as it involves just the removal of tissue around the axillary vein, while level three is the most aggressive as it removes all of the nodal tissue from the axilla. [4] It may be necessary to remove other lymph nodes in addition to the SLN. Each woman has a different number of lymph nodes in her body, so determining how many nodes to remove is based on location, rather than number. [4] The lymph nodes serve as a filtering system for the lymphatic system, so it is important to preserve as many as possible, while also ridding the body of all cancer cells.[ citation needed ]

In order to eliminate micrometastases that are not near lymph nodes and have traveled to distant regions of the body, chemotherapy and radiation therapies are necessary. However, since most micrometastatic tumor cells are in the nonproliferative G0 phase[ clarification needed ], standard cytotoxic chemotherapies may not be as useful. [5] Therefore, adjuvant chemotherapy and adjuvant radiation therapy[ clarification needed ] are more effective to eliminate micrometastases, since they are aimed to target dividing and quiescent cells[ clarification needed ]. Adjuvant therapies are administered after the removal of the lymph nodes. The significance of these therapies is to serve as a “clean up” method for those cells that have migrated elsewhere from the primary tumor. [2] Researchers still question whether this treatment method to rid the body of this small cluster of cells that may or may not progress is worth the side effects that it may cause. [6] Side effects include fatigue, hair loss, nausea, or vomiting. In addition, adjuvant therapies do not always result in a cure and they do not benefit all patients.[ citation needed ]

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<span class="mw-page-title-main">Metastasis</span> Spread of a disease inside a body

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<span class="mw-page-title-main">Sarcoma</span> Cancer originating in connective tissue

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<span class="mw-page-title-main">Anaplastic large-cell lymphoma</span> Medical condition

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<span class="mw-page-title-main">Lymphadenectomy</span> Surgical removal of lymph nodes

Lymphadenectomy, or lymph node dissection, is the surgical removal of one or more groups of lymph nodes. It is almost always performed as part of the surgical management of cancer. In a regional lymph node dissection, some of the lymph nodes in the tumor area are removed; in a radical lymph node dissection, most or all of the lymph nodes in the tumor area are removed.

<span class="mw-page-title-main">Lumpectomy</span> Limited surgical removal of breast tissue

Lumpectomy is a surgical removal of a discrete portion or "lump" of breast tissue, usually in the treatment of a malignant tumor or breast cancer. It is considered a viable breast conservation therapy, as the amount of tissue removed is limited compared to a full-breast mastectomy, and thus may have physical and emotional advantages over more disfiguring treatment. Sometimes a lumpectomy may be used to either confirm or rule out that cancer has actually been detected. A lumpectomy is usually recommended to patients whose cancer has been detected early and who do not have enlarged tumors. Although a lumpectomy is used to allow for most of the breast to remain intact, the procedure may result in adverse affects that can include sensitivity and result in scar tissue, pain, and possible disfiguration of the breast if the lump taken out is significant. According to National Comprehensive Cancer Network guidelines, lumpectomy may be performed for ductal carcinoma in situ (DCIS), invasive ductal carcinoma, or other conditions.

<span class="mw-page-title-main">Invasive carcinoma of no special type</span> Medical condition

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Adjuvant therapy, also known as adjunct therapy, adjuvant care, or augmentation therapy, is a therapy that is given in addition to the primary or initial therapy to maximize its effectiveness. The surgeries and complex treatment regimens used in cancer therapy have led the term to be used mainly to describe adjuvant cancer treatments. An example of such adjuvant therapy is the additional treatment usually given after surgery where all detectable disease has been removed, but where there remains a statistical risk of relapse due to the presence of undetected disease. If known disease is left behind following surgery, then further treatment is not technically adjuvant.

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<span class="mw-page-title-main">Axillary lymph nodes</span> Lymph nodes in the human armpit

The axillary lymph nodes or armpit lymph nodes are lymph nodes in the human armpit. Between 20 and 49 in number, they drain lymph vessels from the lateral quadrants of the breast, the superficial lymph vessels from thin walls of the chest and the abdomen above the level of the navel, and the vessels from the upper limb. They are divided in several groups according to their location in the armpit. These lymph nodes are clinically significant in breast cancer, and metastases from the breast to the axillary lymph nodes are considered in the staging of the disease.

<span class="mw-page-title-main">Breast cancer chemotherapy</span> Medical intervention

Breast cancer chemotherapy refers to the use of cytotoxic drugs (chemotherapy) in the treatment of breast cancer.

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Cancer of unknown primary origin (CUP) is a cancer that is determined to be at the metastatic stage at the time of diagnosis, but a primary tumor cannot be identified. A diagnosis of CUP requires a clinical picture consistent with metastatic disease and one or more biopsy results inconsistent with a tumor cancer.

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<span class="mw-page-title-main">Spiradenoma</span> Medical condition

Spiradenomas (SA) are rare, benign cutaneous adnexal tumors that may progress to become their malignant counterparts, i.e. spiradenocarcinomas (SAC). Cutaneous adnexal tumors are a group of skin tumors consisting of tissues that have differentiated towards one of the four primary adnexal structures found in normal skin: hair follicles, sebaceous sweat glands, apocrine sweat glands, and eccrine sweat glands. SA and SAC tumors were regarded as eccrine gland tumors and termed eccrine spiradenomas and eccrine spiradenocarcinomas, respectively. However, more recent studies have found them to be hair follicle tumors and commonly term them spiradenomas and spiradenocarcinomas, respectively. Further confusing the situation, SA-like and SAC-like tumors are also 1) manifestations of the inherited disorder, CYLD cutaneous syndrome (CCS), and 2) have repeatedly been confused with an entirely different tumor, adenoid cystic carcinomas of the salivary gland. Here, SA and SAC are strictly defined as sporadic hair follicle tumors that do not include the hereditary CCS spiradenomas and heridtary spiradenocarcinoms of CCS or the adenoid cystic carcinomas.

Carcinoma of the tonsil is a type of squamous cell carcinoma. The tonsil is the most common site of squamous cell carcinoma in the oropharynx. It comprises 23.1% of all malignancies of the oropharynx. The tumors frequently present at advanced stages, and around 70% of patients present with metastasis to the cervical lymph nodes. . The most reported complaints include sore throat, otalgia or dysphagia. Some patients may complain of feeling the presence of a lump in the throat. Approximately 20% patients present with a node in the neck as the only symptom.

Mammary secretory carcinoma (MSC), also termed secretory carcinoma of the breast, is a rare form of the breast cancers. MSC usually affects women but in a significant percentage of cases also occurs in men and children. Indeed, McDvitt and Stewart first described MSC in 1966 and termed it juvenile breast carcinoma because an increased number of cases were at that time diagnosed in juvenile females. MSC is the most common form of breast cancer in children, representing 80% of childhood breast cancers, although it accounts for less than 0.15% of all breast cancers.

Papillary carcinomas of the breast (PCB), also termed malignant papillary carcinomas of the breast, are rare forms of the breast cancers. The World Health Organization (2019) classified papillary neoplasms of the breast into 5 types: intraductal papilloma, papillary ductal carcinoma in situ (PDCIS), encapsulated papillary carcinoma (EPC), solid-papillary carcinoma (SPC), and invasive papillary carcinoma (IPC). The latter four carcinomas are considered here; intraductal papilloma is a benign neoplasm. The World Health Organization regarded solid papillary carcinoma as having two subtypes: in situ and invasive SPC.

References

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  2. 1 2 3 4 "Micrometastases in Lymph Nodes Need Treatment". breastcancer.org. 2009-06-04. Retrieved 2018-04-19.
  3. 1 2 3 4 5 Leong, Stanley; Tseng, William (2014-02-05). "Micrometastatic cancer cells in lymph nodes, bone marrow, and blood: Clinical significance and biologic implications". CA: A Cancer Journal for Clinicians. 64 (3): 195–206. doi: 10.3322/caac.21217 . PMID   24500995.
  4. 1 2 "Axillary Node Dissection". Johns Hopkins Medicine. Retrieved 2018-04-19.
  5. Pantel, Klaus; Kote, Richard; Fodstad, Oystein (1999-07-07). "Detection and Clinical Importance of Micrometastatic Disease". Journal of the National Cancer Institute. 91 (13): 1113–1124. doi: 10.1093/jnci/91.13.1113 . PMID   10393719.
  6. Whittington, Elizabeth (2009-12-12). "The Implications of Micrometastases in Early-Stage Breast Cancer Revealed". curetoday.com. Retrieved 2018-04-19.