Cancer staging

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Cancer staging
PurposeDetermining the extent to which a cancer has developed

Cancer staging is the process of determining the extent to which a cancer has grown and spread. A number from I to IV is assigned, with I being an isolated cancer and IV being a cancer that has metastasized and spread from its origin. The stage generally takes into account the size of a tumor, whether it has invaded adjacent organs, how many regional (nearby) lymph nodes it has spread to (if any), and whether it has appeared in more distant locations (metastasized).

Contents

TNM staging system

3D medical illustration depicting the TNM stages in breast cancer 3D medical animation TNM Staging System.jpg
3D medical illustration depicting the TNM stages in breast cancer

Cancer staging can be divided into a clinical stage and a pathologic stage. In the TNM (Tumor, Node, Metastasis) system, clinical stage and pathologic stage are denoted by a small "c" or "p" before the stage (e.g., cT3N1M0 or pT2N0). This staging system is used for most forms of cancer, except brain tumors and hematological malignancies.

Because they use different criteria, clinical stage and pathologic stage often differ. Pathologic staging is usually considered to be more accurate because it allows direct examination of the tumor in its entirety, contrasted with clinical staging which is limited by the fact that the information is obtained by making indirect observations of a tumor which is still in the body. However, clinical staging and pathologic staging often complement each other. Not every tumor is treated surgically, so pathologic staging is not always available. Also, sometimes surgery is preceded by other treatments such as chemotherapy and radiation therapy which shrink the tumor, so the pathologic stage may underestimate the true stage.

Considerations

Correct staging is critical because treatment (particularly the need for pre-operative therapy and/or for adjuvant treatment, the extent of surgery) is generally based on this parameter. Thus, incorrect staging would lead to improper treatment.

For some common cancers the staging process is well-defined. For example, in the cases of breast cancer and prostate cancer, doctors routinely can identify that the cancer is early and that it has low risk of metastasis. [1] In such cases, medical specialty professional organizations recommend against the use of PET scans, CT scans, or bone scans because research shows that the risk of getting such procedures outweighs the possible benefits. [1] Some of the problems associated with overtesting include patients receiving invasive procedures, overutilizing medical services, getting unnecessary radiation exposure, and experiencing misdiagnosis. [1]

Pathologic

Pathologic staging, where a pathologist examines sections of tissue, can be particularly problematic for two specific reasons: visual discretion and random sampling of tissue. "Visual discretion" means being able to identify single cancerous cells intermixed with healthy cells on a slide. Oversight of one cell can mean misstaging and lead to serious, unexpected spread of cancer. "Random sampling" refers to the fact that lymph nodes are cherry-picked from patients and random samples are examined. If cancerous cells present in the lymph node happen not to be present in the slices of tissue viewed, incorrect staging and improper treatment can result.

Current research

New, highly sensitive methods of staging are in development. For example, the mRNA for GCC (guanylyl cyclase c), present only in the luminal aspect of intestinal epithelium, can be identified using molecular screening (RT-PCR) with a high degree of sensitivity and exactitude. Presence of GCC in any other tissue of the body represents colorectal metaplasia. Because of its high sensitivity, RT-PCR screening for GCC greatly reduces underestimation of disease stage. Researchers hope that staging with this level of precision will lead to more appropriate treatment and better prognosis. Furthermore, researchers hope that this same technique can be applied to other tissue-specific proteins.

Systems

Staging systems are specific for each type of cancer (e.g., breast cancer and lung cancer), but some cancers do not have a staging system. Although competing staging systems still exist for some types of cancer, the universally-accepted staging system is that of the UICC, which has the same definitions of individual categories as the AJCC.

Systems of staging may differ between diseases or specific manifestations of a disease.

Blood

Solid

For solid tumors, TNM is by far the most commonly used system, but it has been adapted for some conditions.

Overall stage grouping

Cancer stages.svg

Overall Stage Grouping is also referred to as Roman Numeral Staging. This system uses numerals I, II, III, and IV (plus the 0) to describe the progression of cancer.

Within the TNM system, a cancer may also be designated as recurrent, meaning that it has appeared again after being in remission or after all visible tumor has been eliminated. Recurrence can either be local, meaning that it appears in the same location as the original, or distant, meaning that it appears in a different part of the body.

Stage migration

Stage migration is a change in the distribution of stages in a particular cancer population, induced by either a change in the staging system itself or else a change in technology which allows more sensitive detection of tumor spread and therefore more sensitivity in detecting spread of disease (e.g., the use of MRI scans). Stage migration can lead to curious statistical phenomena (for example, the Will Rogers phenomenon).

Related Research Articles

<span class="mw-page-title-main">Lung cancer</span> Malignant tumor characterized by uncontrolled cell growth in lung tissue

Lung cancer, also known as lung carcinoma, is a malignant tumor that begins in the lung. Lung cancer is caused by genetic damage to the DNA of cells in the airways, often caused by cigarette smoking or inhaling damaging chemicals. Damaged airway cells gain the ability to multiply unchecked, causing the growth of a tumor. Without treatment, tumors spread throughout the lung, damaging lung function. Eventually lung tumors metastasize, spreading to other parts of the body.

<span class="mw-page-title-main">Prostate cancer</span> Male reproductive organ cancer

Prostate cancer is the uncontrolled growth of cells in the prostate, a gland in the male reproductive system below the bladder. Early prostate cancer causes no symptoms. Most cases are detected after screening tests – typically blood tests for levels of prostate-specific antigen (PSA) – indicate unusual growth of prostate tissue. Diagnosis requires a biopsy of the prostate. If cancer is present, the pathologist assigns a Gleason score, with a higher score representing a more dangerous tumor. Medical imaging is performed to look for cancer that has spread outside the prostate. Based on the Gleason score, PSA levels, and imaging results, a cancer case is assigned a stage 1 to 4. Higher stage signifies a more advanced, more dangerous disease.

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

Metastasis is a pathogenic agent's spread from an initial or primary site to a different or secondary site within the host's body; the term is typically used when referring to metastasis by a cancerous tumor. The newly pathological sites, then, are metastases (mets). It is generally distinguished from cancer invasion, which is the direct extension and penetration by cancer cells into neighboring tissues.

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

A sarcoma is a malignant tumor, a type of cancer that arises from cells of mesenchymal origin. Connective tissue is a broad term that includes bone, cartilage, fat, vascular, or other structural tissues, and sarcomas can arise in any of these types of tissues. As a result, there are many subtypes of sarcoma, which are classified based on the specific tissue and type of cell from which the tumor originates. Sarcomas are primary connective tissue tumors, meaning that they arise in connective tissues. This is in contrast to secondary connective tissue tumors, which occur when a cancer from elsewhere in the body spreads to the connective tissue. Sarcomas are one of five different types of cancer, classified by the cell type from which they originate. The word sarcoma is derived from the Greek σάρκωμα sarkōma 'fleshy excrescence or substance', itself from σάρξsarx meaning 'flesh'.

The TNM Classification of Malignant Tumors (TNM) is a globally recognised standard for classifying the anatomical extent of the spread of malignant tumours (cancer). It has gained wide international acceptance for many solid tumor cancers, but is not applicable to leukaemia or tumors of the central nervous system. Most common tumors have their own TNM classification. The TNM staging system is sometimes referred to as the AJCC/UICC staging system or the UICC/AJCC staging system.

<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

Invasive carcinoma of no special type, invasive breast carcinoma of no special type (IBC-NST), invasive ductal carcinoma (IDC), infiltrating ductal carcinoma (IDC) or invasive ductal carcinoma, not otherwise specified (NOS) is a disease. For international audiences this article will use "invasive carcinoma NST" because it is the preferred term of the World Health Organization (WHO).

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.

Prostate cancer staging is the process by which physicians categorize the risk of cancer having spread beyond the prostate, or equivalently, the probability of being cured with local therapies such as surgery or radiation. Once patients are placed in prognostic categories, this information can contribute to the selection of an optimal approach to treatment. Prostate cancer stage can be assessed by either clinical or pathological staging methods. Clinical staging usually occurs before the first treatment and tumour presence is determined through imaging and rectal examination, while pathological staging is done after treatment once a biopsy is performed or the prostate is removed by looking at the cell types within the sample.

<span class="mw-page-title-main">Papillary thyroid cancer</span> Medical condition

Papillary thyroid cancer is the most common type of thyroid cancer, representing 75 percent to 85 percent of all thyroid cancer cases. It occurs more frequently in women and presents in the 20–55 year age group. It is also the predominant cancer type in children with thyroid cancer, and in patients with thyroid cancer who have had previous radiation to the head and neck. It is often well-differentiated, slow-growing, and localized, although it can metastasize.

<span class="mw-page-title-main">Vulvar cancer</span> Cancer involving the vulva

Vulvar cancer is a cancer of the vulva, the outer portion of the female genitals. It most commonly affects the labia majora. Less often, the labia minora, clitoris, or Bartholin's glands are affected. Symptoms include a lump, itchiness, changes in the skin, or bleeding from the vulva.

Breast cancer management takes different approaches depending on physical and biological characteristics of the disease, as well as the age, over-all health and personal preferences of the patient. Treatment types can be classified into local therapy and systemic treatment. Local therapy is most efficacious in early stage breast cancer, while systemic therapy is generally justified in advanced and metastatic disease, or in diseases with specific phenotypes.

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

Lung cancer staging is the assessment of the extent to which a lung cancer has spread from its original source. As with most cancers, staging is an important determinant of treatment and prognosis. In general, more advanced stages of cancer are less amenable to treatment and have a worse prognosis.

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

Hypopharyngeal cancer is a disease in which malignant cells grow in the hypopharynx the area where the larynx and esophagus meet.

Breast cancer classification divides breast cancer into categories according to different schemes criteria and serving a different purpose. The major categories are the histopathological type, the grade of the tumor, the stage of the tumor, and the expression of proteins and genes. As knowledge of cancer cell biology develops these classifications are updated.

<span class="mw-page-title-main">Male breast cancer</span> Medical condition

Male breast cancer (MBC) is a cancer in males that originates in their breasts. Males account for less than 1% of new breast cancers with about 20,000 new cases being diagnosed worldwide every year. Its incidence rates in males vs. females are, respectively, 0.4 and 66.7 per 100,000 person-years. The worldwide incidences of male as well as female breast cancers have been increasing over the last few decades. Currently, one of every 800 men are estimated to develop this cancer during their lifetimes.

<span class="mw-page-title-main">Cancer treatment</span> Overview of various treatment possibilities for cancer

Cancer treatments are a wide range of treatments available for the many different types of cancer, with each cancer type needing its own specific treatment. Treatments can include surgery, chemotherapy, radiation therapy, hormonal therapy, targeted therapy including small-molecule drugs or monoclonal antibodies, and PARP inhibitors such as olaparib. Other therapies include hyperthermia, immunotherapy, photodynamic therapy, and stem-cell therapy. Most commonly cancer treatment involves a series of separate therapies such as chemotherapy before surgery. Angiogenesis inhibitors are sometimes used to enhance the effects of immunotherapies.

Colon cancer staging is an estimate of the amount of penetration of a particular cancer. It is performed for diagnostic and research purposes, and to determine the best method of treatment. The systems for staging colorectal cancers depend on the extent of local invasion, the degree of lymph node involvement and whether there is distant metastasis.

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.

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