Cancer treatment facts for kids

Quick facts for kids Cancer treatment
A patient prepared for radiation therapy
Specialty	Oncology
ICD-10-PCS	110000053

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.

The choice of therapy depends upon the location and grade of the tumor and the stage of the disease, as well as the general state of the patient. Biomarker testing can help to determine the type of cancer, and indicate the best therapy. A number of experimental cancer treatments are continuously under development. In 2023 it was estimated that one in five people will be diagnosed with cancer at some point in their lifetime.

The primary goal of cancer treatment is to either cure the cancer by its complete removal, or to considerably prolong the life of the individual. Palliative care is involved when the prognosis is poor and the cancer termed as terminal. There are many types of cancer, and many of these can be successfully treated if detected early enough.

Types of treatments

The treatment of cancer has undergone evolutionary changes as understanding of the underlying biological processes has increased. Tumor removal surgeries have been documented in ancient Egypt, hormone therapy and radiation therapy were developed in the late 19th century. Chemotherapy, immunotherapy and newer targeted therapies are products of the 20th century. As new information about the biology of good cancer emerges, treatments will be developed and modified to increase effectiveness, precision, survivability, and quality of life.

Surgery

Malignant tumours can be cured if entirely removed by surgery. But if the cancer has already spread (metastasized) to other sites, complete surgical excision is usually impossible. In the Halstedian model of cancer progression, tumors grow locally, then spread to the lymph nodes, then to the rest of the body. This has given rise to the popularity of local-only treatments such as surgery for small cancers. Even small localized tumors are increasingly recognized as possessing metastatic potential.

Examples of surgical procedures for cancer include mastectomy, and lumpectomy for breast cancer, prostatectomy for prostate cancer, and lung cancer surgery for non-small cell lung cancer. The goal of the surgery can be either the removal of only the tumor, the entire organ, or part of the organ. A single cancer cell is invisible to the naked eye but can regrow into a new tumor, a process called recurrence. For this reason, the pathologist will examine the surgical specimen to determine if a margin of healthy tissue is present, thus decreasing the chance that microscopic cancer cells are left in the patient.

In addition to removal of the primary tumor, surgery is often necessary for staging, e.g. determining the extent of the disease and whether it has metastasized to regional lymph nodes. Staging is a major determinant of prognosis and of the need for adjuvant therapy. Occasionally, surgery is necessary to control symptoms, such as spinal cord compression or bowel obstruction. This is referred to as palliative treatment.

Surgery may be performed before or after other forms of treatment. Treatment before surgery is often described as neoadjuvant. In breast cancer, the survival rate of patients who receive neoadjuvant chemotherapy are no different from those who are treated following surgery. Giving chemotherapy earlier allows oncologists to evaluate the effectiveness of the therapy, and may make removal of the tumor easier. However, the survival advantages of neoadjuvant treatment in lung cancer are less clear.

Radiation therapy

Radiation therapy (radiotherapy) is the use of ionizing radiation to kill cancer cells and shrink tumors by damaging their DNA causing cellular death. Radiation therapy can either damage DNA directly or create charged particles (free radicals) within the cells that can in turn damage the DNA. Radiation therapy can be administered externally via external beam radiotherapy or internally via brachytherapy. The effects of radiation therapy are localised and confined to the region being treated. Although radiation damages both cancer cells and normal cells, most normal cells can recover from the effects of radiation and function properly. The goal of radiation therapy is to damage as many cancer cells as possible, while limiting harm to nearby healthy tissue. Hence, it is given in many fractions, allowing healthy tissue to recover between fractions.

Radiation therapy may be used to treat almost every type of solid tumor, and may also be used to treat leukemia and lymphoma. Radiation dose to each site depends on a number of factors, including the radio sensitivity of each cancer type and whether there are tissues and organs nearby that may be damaged by radiation. Thus, as with every form of treatment, radiation therapy is not without its side effects.

Radiation therapy can lead to dry mouth from exposure of salivary glands to radiation, resulting in decreased saliva secretion. Post therapy, the salivary glands will resume functioning but rarely in the same fashion. Dry mouth caused by radiation can be a permanent problem.

Chemotherapy

Chemotherapy is the treatment of cancer with drugs ("anticancer drugs") that can destroy cancer cells. Chemotherapy can be given in a variety of ways such as injections into the muscles, skin, artery, or vein, or it could even be taken by mouth in the form of a pill. In current usage, the term "chemotherapy" usually refers to cytotoxic drugs which affect rapidly dividing cells in general, in contrast with targeted therapy (see below). Chemotherapy drugs interfere with cell division in various possible ways, e.g. with the duplication of DNA or the separation of newly formed chromosomes. Most forms of chemotherapy target all rapidly dividing cells and are not specific to cancer cells, although some degree of specificity may come from the inability of many cancer cells to repair DNA damage, while normal cells generally can. Hence, chemotherapy has the potential to harm healthy tissue, especially those tissues that have a high replacement rate (e.g. intestinal lining). These cells usually repair themselves after chemotherapy.

Because some drugs work better together than alone, two or more drugs are often given at the same time. This is called "combination chemotherapy"; most chemotherapy regimens are given in a combination.

Since chemotherapy affects the whole body, it can have a wide range of side effects. Patients often find that they start losing their hair since the drugs that are combatting the cancer cells also attack the cells in the hair roots. This powerful treatment can also lead to fatigue, loss of appetite, and vomiting depending on the person.

The treatment of some leukaemias and lymphomas requires the use of high-dose chemotherapy, and total body irradiation (TBI). This treatment ablates the bone marrow, and hence the body's ability to recover and repopulate the blood. For this reason, bone marrow, or peripheral blood stem cell harvesting is carried out before the ablative part of the therapy, to enable "rescue" after the treatment has been given. This is known as autologous stem cell transplantation.

Targeted therapies

Targeted therapy, which first became available in the late 1990s, has had a significant impact in the treatment of some types of cancer, and is currently a very active research area. This constitutes the use of agents specific for the deregulated proteins of cancer cells. Small molecule drugs are targeted therapy drugs that are generally inhibitors of enzymatic domains on mutated, overexpressed, or otherwise critical proteins within the cancer cell. Prominent examples are the tyrosine kinase inhibitors imatinib (Gleevec/Glivec) and gefitinib (Iressa).

Monoclonal antibody therapy is another strategy in which the therapeutic agent is an antibody which specifically binds to a protein on the surface of the cancer cells. Examples include the anti-HER2/neu antibody trastuzumab (Herceptin) used in breast cancer, and the anti-CD20 antibody rituximab, used in a variety of B-cell malignancies.

Targeted therapy can also involve small peptides as "homing devices" which can bind to cell surface receptors or affected extracellular matrix surrounding the tumor. Radionuclides which are attached to these peptides (e.g. RGDs) eventually kill the cancer cell if the nuclide decays in the vicinity of the cell. Especially oligo- or multimers of these binding motifs are of great interest, since this can lead to enhanced tumor specificity and avidity.

Photodynamic therapy (PDT) is a ternary treatment for cancer involving a photosensitizer, tissue oxygen, and light (often using lasers). PDT can be used as treatment for basal cell carcinoma (BCC) or lung cancer; PDT can also be useful in removing traces of malignant tissue after surgical removal of large tumors. In February 2019, medical scientists announced that iridium attached to albumin, creating a photosensitized molecule, can penetrate cancer cells and, after being irradiated with light, destroy the cancer cells.

High-energy therapeutic ultrasound could increase higher-density anti-cancer drug load and nanomedicines to target tumor sites by 20x fold higher than traditional target cancer therapy.

Targeted therapies under pre-clinical development as potential cancer treatments include morpholino splice switching oligonucleotides, which induce ERG exon skipping in prostate cancer models, multitargeted kinase inhibitors that inhibit the PI3K with other pathways including MEK and PIM, and inhibitors of NF-κB in models of chemotherapy resistance.

A systematic review published in Cochrane database found that targeted therapies significantly improve progression-free survival by 35 to 40% in metastatic or relapsed cancer. While the research points to promising clinical outcomes, there is still limited evidence on the long-term effects of targeted therapies in terms of overall survival, quality of life, and severe adverse events.

Immunotherapy

Cancer immunotherapy refers to a diverse set of therapeutic strategies designed to induce the patient's own immune system to fight the tumor. Contemporary methods for generating an immune response against tumors include intravesical BCG immunotherapy for superficial bladder cancer, and use of interferons and other cytokines to induce an immune response in renal cell carcinoma and melanoma patients. Cancer vaccines to generate specific immune responses are the subject of intensive research for a number of tumors, notably malignant melanoma and renal cell carcinoma. Sipuleucel-T is a vaccine-like strategy for prostate cancer in which dendritic cells from the patient are loaded with prostatic acid phosphatase peptides to induce a specific immune response against prostate-derived cells. It gained FDA approval in 2010.

Allogeneic hematopoietic stem cell transplantation (usually from the bone marrow) from a genetically non-identical donor can be considered a form of immunotherapy, since the donor's immune cells will often attack the tumor in a phenomenon known as graft-versus-tumor effect. For this reason, allogeneic HSCT leads to a higher cure rate than autologous transplantation for several cancer types, although the side effects are also more severe.

The cell based immunotherapy in which the patients own natural killer cells (NKs) and cytotoxic T cells are used has been in practice in Japan since 1990. NK cells and TCs primarily kill the cancer cells when they are developed. This treatment is given together with the other modes of treatment such as surgery, radiotherapy or chemotherapy and termed autologous immune enhancement therapy (AIET).

Immune checkpoint therapy focuses on two immune checkpoint proteins, cytotoxic T-lymphocyte associated protein 4 (CTLA-4) and programmed cell death protein 1 (PD-1). Under normal conditions, the immune system utilizes checkpoint proteins as negative feedback mechanisms to return to homeostasis once pathogens have been cleared from the body. In a tumor microenvironment, cancer cells can commandeer this physiological regulatory system to "put a brake" on the anti-cancer immune response and evade immune surveillance. 2018 Nobel Prize in medicine is awarded to Dr. James Allison of University of Texas MD Anderson Cancer Center in U.S. and Dr. Tasuku Honjo Kyoto University in Japan for their contributions in advance of PD-1 and CTLA-4 immune checkpoint therapy.

Hormonal therapy

The growth of some cancers can be inhibited by providing or blocking certain hormones. Common examples of hormone-sensitive tumors include certain types of breast and prostate cancers. Blocking estrogen or testosterone is often an important additional treatment. In certain cancers, administration of hormone agonists, such as progestogens may be therapeutically beneficial. Although the side effects from hormone therapy vary depending on the type, patients can experience symptoms such as hot flashes, nausea, and fatigue.

Angiogenesis inhibitors

Angiogenesis inhibitors prevent the extensive growth of blood vessels (angiogenesis) that tumors need to survive and grow. Continued growth allows the invasion of cells into neighbouring tissues, and metastasis into distal tissues. There are many approved angiogenesis inhibitors including bevacizumab, axitinib, and cabozantinib.

Flavonoids have been shown to downregulate the angiogenic stimulation of VEGF and Hypoxia-inducible factor (HIF) but none have reached clinical trials.

Exercise prescription

Exercise prescription is becoming a mainstream adjunct treatment for cancer, based on studies which show that exercise (compared to no exercise) is associated with reduced recurrence rates, improved mortality outcomes, reduction of side effects from traditional cancer treatments. Although it is uncertain whether improved outcomes with exercise are correlated or causative, the benefit-risk ratio of including exercise as part of cancer treatment is large, as exercise has further benefits (e.g. cardiovascular, mental health) without major risks, although there is a small risk of overuse injury if added too aggressively. Exercise physiologists and exercise medicine specialists can assist oncologists and primary care practitioners with exercise prescription in cancer patients.

Walking is usually an excellent exercise option as an adjunct cancer treatment.

Synthetic lethality

Synthetic lethality arises when a combination of deficiencies in the expression of two or more genes leads to cell death, whereas a deficiency in only one of these genes does not. The deficiencies can arise through mutations, epigenetic alterations or inhibitors of one or both of the genes.

Cancer cells are frequently deficient in a DNA repair gene. (Also see DNA repair deficiency in cancer.) This DNA repair defect either may be due to mutation or, often, epigenetic silencing (see epigenetic silencing of DNA repair). If this DNA repair defect is in one of seven DNA repair pathways (see DNA repair pathways), and a compensating DNA repair pathway is inhibited, then the tumor cells may be killed by synthetic lethality. Non-tumorous cells, with the initial pathway intact, can survive.

Ovarian cancer

Mutations in DNA repair genes BRCA1 or BRCA2 (active in homologous recombinational repair) are synthetically lethal with inhibition of DNA repair gene PARP1 (active in the base excision repair and in the microhomology-mediated end joining pathways of DNA repair).

Ovarian cancers have a mutational defect in BRCA1 in about 18% of patients (13% germline mutations and 5% somatic mutations) (see BRCA1). Olaparib, a PARP inhibitor, was approved in 2014 by the US FDA for use in BRCA-associated ovarian cancer that had previously been treated with chemotherapy. The FDA, in 2016, also approved the PARP inhibitor rucaparib to treat women with advanced ovarian cancer who have already been treated with at least two chemotherapies and have a BRCA1 or BRCA2 gene mutation.

Colon cancer

In colon cancer, epigenetic defects in the WRN gene appear to be synthetically lethal with inactivation of TOP1. In particular, irinotecan inactivation of TOP1 was synthetically lethal with deficient expression of the DNA repair WRN gene in patients with colon cancer. In a 2006 study, 45 patients had colonic tumors with hypermethylated WRN gene promoters (silenced WRN expression), and 43 patients had tumors with unmethylated WRN gene promoters, so that WRN protein expression was high. Irinotecan was more strongly beneficial for patients with hypermethylated WRN promoters (39.4 months survival) than for those with unmethylated WRN promoters (20.7 months survival). The WRN gene promoter is hypermethylated in about 38% of colorectal cancers.

There are five different stages of colon cancer, and these five stages all have treatment:

• Stage 0, is where the patient is required to undergo surgery to remove the polyp (American Cancer Society).
• Stage 1, depending on the location of the cancer in the colon and lymph nodes, the patient undergoes surgery just like Stage 0.
• Stage 2 patients undergoes removing nearby lymph nodes, but depending on what the doctor says, the patent might have to undergo chemotherapy after surgery (if the cancer is at higher risk of coming back).
• Stage 3, is where the cancer has spread all throughout the lymph nodes but not yet to other organs or body parts. When getting to this stage, Surgery is conducted on the colon and lymph nodes, then the doctor orders Chemotherapy (FOLFOX or CapeOx) to treat the colon cancer in the location needed (American Cancer Society). The last a patient can get is Stage 4.
• Stage 4 patients only undergo surgery if it is for the prevention of the cancer, along with pain relief. If the pain continues with these two options, the doctor might recommended radiation therapy. The main treatment strategy is chemotherapy due to how aggressive the cancer becomes in this stage, not only to the colon but to the lymph nodes.

Symptom control and palliative care

Although the control of the symptoms of cancer is not typically thought of as a treatment directed at the cancer, it is an important determinant of the quality of life of cancer patients, and plays an important role in the decision whether the patient is able to undergo other treatments. In general, doctors have the therapeutic skills to reduce pain including, chemotherapy-induced nausea and vomiting, diarrhea, hemorrhage and other common problems in cancer patients. The multidisciplinary specialty of palliative care has increased specifically in response to the symptom control needs for these groups of patients.

Mental struggles/pain

Cancer patients undergo many obstacles and one of these includes mental strain. It is very common for cancer patients to become stressed, overwhelmed, uncertain, and even depressed. The use of chemo is a very harsh treatment causing the cells of the body to die. Physical effects like this do not only inflict pain but also cause patients to become mentally exhausted and want to give up. For a lot of reasons including these, hospitals offer many types of therapy and mental healing. Some of these include yoga, meditation, communication therapy, and spiritual ideas. All of these are meant to calm and relax the mind, or to give hope for the patients that may feel drained.

Insomnia

A common disorder experienced by people that have survived cancer treatments is insomnia. Almost 60% of cancer survivors experience insomnia, and if it is not treated properly it can have long term effects on physiological and physical health. Insomnia is defined as dissatisfaction with sleep duration or quality and difficulties initiating or maintaining sleep. Insomnia can heavily reduce one's quality of life. Cognitive behavioral therapy has been seen to reduce insomnia and depression for cancer survivors.

Muscle strength

Decreased muscle strength is a common side effect to many different cancer treatments. Because of this, exercise is very important especially in the first year after treatment. It has been shown that yoga, water exercise, and pilates can improve the emotional well-being and quality of life of breast cancer survivors.

Fatigue

Fatigue is an unrelenting feeling of physical and mental tiredness that cannot be traced back to activity levels. It is a very common experience in cancer survivors, with most patients reporting some level of fatigue before, during, and after treatment. The cause of the fatigue can be due to the cancer itself, but frequently it is medical interventions to treat the cancer – like chemotherapy, radiation, surgery, and hormone therapy – that cause the feelings of extreme tiredness. The exact processes behind cancer-related fatigue are unknown. However, evidence suggests that biological processes like inflammation and stress hormone disruption may play a role. In addition, pre-existing risk factors like a genetic predisposition, sleeping troubles, a pre-existing mood disorder, adverse childhood experiences, and low levels of physical activity are associated with increased levels of cancer-related fatigue.

Treatment options for cancer-related fatigue can be pharmacological or non-pharmacological. Medications like erythropoietin, stimulants, and antidepressants can be prescribed, but their efficacy is modest. Thus, non-pharmacological interventions are the preferred treatment for cancer-related fatigue. Aerobic exercise and psychosocial interventions like cognitive behavioral therapy and mindfulness show promise in reducing feelings of fatigue in cancer patients.

Hospice care

Hospice care provides palliative care at home, or in a dedicated hospice institution, for a person with an advanced illness termed as terminal. Untreated cancer will prove terminal, and sometimes a choice is made to forgo treatment and its unpleasant side effects, and opt instead for hospice care. Hospice care aims to provide support for the person's medical, emotional, social, practical, psychological, and spiritual needs.

Advance care planning (ACP) can help a person to decide for themself their future care wishes as they approach end of life. ACP helps adults at any stage of health to decide, and record in writing, their wishes for medical treatment preferences, and future wants, preferably as previously discussed with relatives or carers.

See also