What is the Anus?
The large intestine is part of the body’s gastrointestinal (GI) tract or digestive system. The colon and rectum make up the large intestine, which plays an important role in the body’s ability to process waste. The colon makes up the first 5 to 6 feet of the large intestine, and the rectum makes up the last 6 inches, ending at the anus.
The colon and rectum have 5 sections. The ascending colon is the portion that extends from a pouch called the cecum to the portion of the colon that is near the liver. The cecum is the beginning of the large intestine into which the small intestine empties; it’s on the right side of the abdomen. The transverse colon crosses the top of the abdomen. The descending colon takes waste down the left side. Finally, the sigmoid colon at the bottom takes waste a few more inches, down to the rectum. Waste leaves the body through the anus.
What is Anal Cancer?
Colorectal cancer begins when healthy cells in the lining of the colon or rectum change and grow out of control, forming a mass called a tumour. A tumour can be cancerous or benign. A cancerous tumour is malignant, meaning it can grow and spread to other parts of the body. A benign tumour means the tumour can grow but will not spread. These changes usually take years to develop. Both genetic and environmental factors can cause the changes. However, when a person has an uncommon inherited syndrome, changes can occur in months or years.
Types of Anal Cancer
Colorectal cancer is typically classified into different types based on the type of cells that give rise to cancer, the location within the colon or rectum, and the growth pattern of the cancer cells.
Here are the common types of colorectal cancer –
Adenocarcinoma
This is the most common type of colorectal cancer, accounting for more than 95% of cases. It develops from the cells that line the inside of the colon or rectum.
Carcinoid tumours
These are rare and slow-growing tumors that develop from hormone-producing cells in the gastrointestinal tract. They usually occur in the rectum.
Gastrointestinal stromal tumors (GISTs)
These are rare tumours that start in the cells that support the tissues of the gastrointestinal tract. They can occur anywhere in the gastrointestinal tract, including the colon and rectum.
Lymphoma
This is a rare cancer that affects the lymphatic system, which is part of the immune system. It can occur in the colon or rectum, but it’s more commonly found in other parts of the body.
Sarcoma
These are rare cancers that develop in the connective tissues, such as muscle, fat, or blood vessels. They can occur in the colon or rectum, but they are more commonly found in other parts of the body.
Risk Factors of Anal Cancer
There are several risk factors associated with an increased likelihood of developing colorectal cancer. These include –
Family history
Family history may signify either a genetic abnormality or shared environmental factors, or a combination of these factors. About 15% of all colorectal cancers occur in patients with a history of colorectal cancer in first-degree relatives.
Sedentary lifestyle
Lack of physical activity and a sedentary lifestyle can increase the risk of colorectal cancer.
Obesity
Being overweight or obese increases the risk of colorectal cancer, especially in men.
Smoking
Men and women smoking during the previous 20 years have three times the relative risk for small adenomas (<1 cm) but not for larger ones. Smoking for >20 years was associated with 2.5 times the relative risk for larger adenomas.
Inflammatory bowel disease (IBD)
Individuals with Crohn’s disease or ulcerative colitis have a higher risk of developing colorectal cancer. account for 27% of melanoma cases, whereas individuals with few common nevi (0 to 10) account for only 4% of melanoma cases.
- Ulcerative colitis is a clear risk factor for colon cancer. About 1% of colorectal cancer patients have a history of chronic ulcerative colitis. The risk for the development of cancer in these patients varies inversely with the age of onset of the colitis and directly with the extent of colonic involvement and duration of active disease.
- Crohn disease: Patients with colorectal Crohn disease are at 1.5 to 2 times increased risk for colorectal cancer. The risk is less than that of those with ulcerative colitis.
Diet
Populations with high intake of fat, higher caloric intakes, and low intake of fiber (fruits, vegetables, and grains) characterized as a westernized diet tend to have an increased risk for colorectal cancer in most but not all studies.
Symptoms of Anal Cancer
In its early stages, colorectal cancer may not produce any noticeable symptoms. However, as cancer grows and spreads, it can cause several symptoms. Here are some of the common symptoms of colorectal cancer –
- Changes in bowel habits, such as diarrhoea or constipation last for more than a few days.
- Blood in the stool or rectal bleeding, may appear as bright red or very dark.
- Abdominal pain or discomfort, including cramping or bloating.
- Unexplained weight loss.
- Fatigue or weakness.
- Narrow stools.
- Feeling like you need to have a bowel movement that is not relieved by doing so.
- Nausea or vomiting.
These symptoms can be caused by other conditions, such as haemorrhoids or inflammatory bowel disease. However, if you experience any of these symptoms, especially if they persist for more than a few days, you should consult your healthcare provider for an evaluation. Early detection of colorectal cancer is key to successful treatment and improved outcomes. Screening tests such as colonoscopy can help detect cancer at an early stage, even before symptoms appear.
Diagnoses of Anal Cancer
The diagnosis of colorectal cancer typically involves several steps, including –
Biopsy confirmation:
Biopsy confirmation of malignancy via colonoscopy or via CTguided fine-needle aspiration is important. US-guided biopsy of the liver metastases can also be diagnostic.
General evaluation:
General evaluation includes a complete physical examination with digital rectal examination, CBC, LFT, and chest imaging.
Carcinoembryonic antigen (CEA) screening:
CEA screening is recommended by the American Society of Clinical Oncology (ASCO) as a means of identifying early recurrence despite the lack of elevation in 40% of individuals with metastatic disease. A preoperative CEA can be useful as a prognostic factor in determining if the primary tumour is associated with CEA elevation. Preoperative CEA elevation implies that CEA may aid in the early identification of metastases because metastatic tumour cells are more likely to result in CEA elevation in this circumstance.
Endoscopy (or CT colonography):
Colonography is indicated to assess the entire colonic mucosa because about 3% of patients have synchronous colorectal cancers and a larger percentage have additional premalignant polyps. In patients where the initial full colonoscopy was not possible due to a distal obstruction, deserve a full evaluation after recovery from initial surgical resection.
Preventions and Treatments for Anal Cancer
Preventions to be considered are as follows
There are several measures that can be taken to help prevent colorectal cancer. These include –
- Periodic sigmoidoscopy or colonoscopy identifies and removes precancerous lesions (polyps) and reduces the incidence of colorectal cancer in patients who undergo colonoscopic polypectomy.
- Diets that are high in fiber and low in fat or that contain calcium supplements, or both, may deter polyp progression to cancer.
- Nonsteroidal anti-inflammatory drugs (NSAIDs): In a randomized, double-blind, placebo-controlled study of patients with familial polyposis, sulindac at a dose of 150 mg b.i.d. significantly decreased the mean number and mean diameter of polyps as compared with those in patients given placebo.
Treatments required for Anal Cancer
The treatment for colorectal cancer depends on several factors, including the stage of cancer, the location of the tumour, and the patient’s overall health. Here are some of the common treatments for colorectal cancer –
Surgery is the only universally accepted potentially curative treatment for colorectal cancer. Curative surgery should excise the tumour with wide margins and maximize regional lymphadenectomy such that at least 12 lymph nodes are available for pathologic evaluation. For lesions above the rectum, resection of the tumour with a minimum 5-cm margin of the grossly negative colon is considered adequate, although the ligation of vascular trunks required to perform an adequate lymphadenectomy may necessitate larger bowel resections. Laparoscopic colectomy approaches have been developed and appear to be equally effective staging and therapeutic approaches to open colectomy, with modest decreases in hospital stay and pain medication use and improved cosmetic results. Subtotal colectomy and ileoproctostomy may be advisable for patients with potentially curable colon cancer and with adenomas scattered in the colon or for patients with a personal history of prior colorectal cancer or a family history of colorectal cancer in first-degree relatives.
- Arterial supply. Excision of a tumour in the right colon should include the right branch of the middle colic artery as well as the entire ileocolic and right colic artery. Excision of a tumour at the hepatic or splenic flexure should include the entire distribution of the middle colic artery.
- Avoidance of permanent colostomy in middle and low rectal cancers has been encouraged by the emergence of new surgical stapling techniques as well as the use of preoperative chemotherapy and radiation to shrink tumours prior to resection.
- Rectal tumours may be treatable by primary resection and more distal anastomosis, usually without even a temporary (anastomosisprotective) colostomy, if the lower edge is above 5 cm from the anal verge.
Chemotherapy is the use of drugs to destroy cancer cells, usually by keeping the cancer cells from growing, dividing, and making more cells.
A chemotherapy regimen, or schedule, usually consists of a specific number of cycles given over a set period of time. A patient may receive 1 drug at a time or a combination of different drugs given at the same time.
Chemotherapy may be given after surgery to eliminate any remaining cancer cells. For some people with rectal cancer, the doctor will give chemotherapy and radiation therapy before surgery to reduce the size of a rectal tumour and reduce the chance of cancer returning.
Many drugs are approved by the U.S. Food and Drug Administration (FDA) to treat colorectal cancer in the United States. Your doctor may recommend 1 or more of them at different times during treatment. Sometimes these are combined with targeted therapy drugs.
Radiation therapy is the use of high-energy x-rays to destroy cancer cells. It is commonly used for treating rectal cancer because this kind of tumor tends to recur near where it originally started. A doctor who specializes in giving radiation therapy to treat cancer is called a radiation oncologist. A radiation therapy regimen, or schedule, usually consists of a specific number of treatments given over a set period of time.
- External-beam radiation therapy: External-beam radiation therapy uses a machine to deliver x-rays to where the cancer is located. Radiation treatment is usually given 5 days a week for several weeks. It may be given in the doctor’s office or at the hospital.
- Stereotactic radiation therapy: Stereotactic radiation therapy is a type of external-beam radiation therapy that may be used if colorectal cancer has spread to the liver or lungs. This type of radiation therapy delivers a large, precise radiation dose to a small area. This technique can help save parts of the liver and lung tissue that might otherwise have to be removed during surgery. However, not all cancers that have spread to the liver or lungs can be treated in this way.
- Radiation therapy for rectal cancer: For rectal cancer, radiation therapy may be used before surgery, called neoadjuvant therapy, to shrink the tumour so that it is easier to remove. It may also be used after surgery to destroy any remaining cancer cells. Both approaches have worked to treat this disease. Chemotherapy is often given at the same time as radiation therapy to increase the effectiveness of the radiation therapy. This is called chemoradiation therapy.
For colorectal cancer, the following targeted therapies may be options.
1. Anti-angiogenesis therapy: Anti-angiogenesis therapy is focused on stopping angiogenesis, which is the process of making new blood vessels. Because a tumour needs the nutrients delivered by blood vessels to grow and spread, the goal of anti-angiogenesis therapies is to “starve” the tumour.
2. Epidermal growth factor receptor (EGFR) inhibitors. Researchers have found that drugs that block EGFR may be effective for stopping or slowing the growth of colorectal cancer.
- Cetuximab (Erbitux)
- Panitumumab (Vectibix)
3. HER2-targeted therapy: Some tumors express a protein called HER2 that can be targeted by specific medications. If this happens, the cancer is called HER2-positive. For people with HER2-positive advanced colorectal cancer, treatment with a combination of tucatinib (Tukysa) and trastuzumab (Herceptin and other brand names) may be an option. This combination may only be used if there are no mutations in the RAS gene, surgery is not an option, and chemotherapy has stopped working and/or caused side effects that require stopping treatment.
4. Combined targeted therapies: Some tumors have a specific mutation, called BRAF V600E, that can be detected by an FDA-approved test. A class of targeted treatments called BRAF inhibitors can be used to treat tumors with this mutation. A combination using the BRAF inhibitor encorafenib (Braftovi) and cetuximab may be used to treat people with metastatic colorectal cancer with this mutation who have received at least 1 previous treatment.
Immunotherapy uses the body’s natural defences to fight cancer by improving your immune system’s ability to attack cancer cells.
Checkpoint inhibitors are an important type of immunotherapy used to treat colorectal cancer.
- Pembrolizumab (Keytruda): Pembrolizumab targets PD-1, a receptor on tumor cells, preventing the tumor cells from hiding from the immune system. Pembrolizumab is used to treat unresectable or metastatic colorectal cancers that have a molecular feature called microsatellite instability (MSI-H) or mismatch repair deficiency (dMMR) (see Diagnosis). Unresectable means surgery is not an option.
- Nivolumab (Opdivo): Nivolumab is used to treat people who are 12 or older and have MSI-H or dMMR metastatic colorectal cancer that has grown or spread after treatment with chemotherapy with a fluoropyrimidine (such as capecitabine and fluorouracil), oxaliplatin, and irinotecan.
- Denvax Immunotherapy: Denvax is a treatment known as cancer immunotherapy. It boosts the immune system to fight against cancer, mostly solid tumours. Denvax is targeted therapy and comes under the 4th modality of cancer treatment called cancer Immunotherapy.
Dendritic cells are cells of the immune system that help in the fight against cancer. Denvax treatment is customized dendritic cell-based cancer immunotherapy. Denvax shows the most promise at preventing a recurrence of cancer after surgery, chemotherapy or radiation because the immune system will need to recognize and attack a smaller number of cancer cells.
- Dostarlimab (Jemperli): Dostarlimab is a PD-1 immune checkpoint inhibitor. It may be used to treat recurrent or metastatic colorectal cancers that have dMMR.
- Nivolumab and ipilimumab (Yervoy) combination: This combination of checkpoint inhibitors is approved to treat patients who are 12 or older and have MSI-H or dMMR metastatic colorectal cancer that has grown or spread after treatment with chemotherapy with a fluoropyrimidine, oxaliplatin, and irinotecan.
References:
- Manual of Clinical Oncology by Bartosz Chmeilowski and Mary Territo
- cancer.net
What are Colon and Rectum?
The large intestine is part of the body’s gastrointestinal (GI) tract or digestive system. The colon and rectum make up the large intestine, which plays an important role in the body’s ability to process waste. The colon makes up the first 5 to 6 feet of the large intestine, and the rectum makes up the last 6 inches, ending at the anus.
The colon and rectum have 5 sections. The ascending colon is the portion that extends from a pouch called the cecum to the portion of the colon that is near the liver. The cecum is the beginning of the large intestine into which the small intestine empties; it’s on the right side of the abdomen. The transverse colon crosses the top of the abdomen. The descending colon takes waste down the left side. Finally, the sigmoid colon at the bottom takes waste a few more inches, down to the rectum. Waste leaves the body through the anus.
What is Colorectal Cancer?
Colorectal cancer begins when healthy cells in the lining of the colon or rectum change and grow out of control, forming a mass called a tumour. A tumour can be cancerous or benign. A cancerous tumour is malignant, meaning it can grow and spread to other parts of the body. A benign tumour means the tumour can grow but will not spread. These changes usually take years to develop. Both genetic and environmental factors can cause the changes. However, when a person has an uncommon inherited syndrome, changes can occur in months or years.
What are Polyps?
The main importance of polyps is the well-recognized potential of a subset to evolve into colorectal cancer. The evolution to cancer is a multistage process that proceeds through mucosal cell hyperplasia, adenoma formation, and growth and dysplasia to malignant transformation and invasive cancer. Oncogene activation, tumour suppressor gene inactivation, deficient DNA mismatch repair enzymes, and chromosomal deletion may lead to adenoma formation, growth with increasing dysplasia, and invasive carcinoma.
Types of Colorectal Cancer
Colorectal cancer is typically classified into different types based on the type of cells that give rise to cancer, the location within the colon or rectum, and the growth pattern of the cancer cells.
Here are the common types of colorectal cancer –
Adenocarcinoma
This is the most common type of colorectal cancer, accounting for more than 95% of cases. It develops from the cells that line the inside of the colon or rectum.
Carcinoid tumours
These are rare and slow-growing tumors that develop from hormone-producing cells in the gastrointestinal tract. They usually occur in the rectum.
Gastrointestinal stromal tumors (GISTs)
These are rare tumours that start in the cells that support the tissues of the gastrointestinal tract. They can occur anywhere in the gastrointestinal tract, including the colon and rectum.
Lymphoma
This is a rare cancer that affects the lymphatic system, which is part of the immune system. It can occur in the colon or rectum, but it’s more commonly found in other parts of the body.
Sarcoma
These are rare cancers that develop in the connective tissues, such as muscle, fat, or blood vessels. They can occur in the colon or rectum, but they are more commonly found in other parts of the body.
Risk Factors of Colorectal Cancer
There are several risk factors associated with an increased likelihood of developing colorectal cancer. These include –
Family history
Family history may signify either a genetic abnormality or shared environmental factors, or a combination of these factors. About 15% of all colorectal cancers occur in patients with a history of colorectal cancer in first-degree relatives.
Sedentary lifestyle
Lack of physical activity and a sedentary lifestyle can increase the risk of colorectal cancer.
Obesity
Being overweight or obese increases the risk of colorectal cancer, especially in men.
Smoking
Men and women smoking during the previous 20 years have three times the relative risk for small adenomas (<1 cm) but not for larger ones. Smoking for >20 years was associated with 2.5 times the relative risk for larger adenomas.
Inflammatory bowel disease (IBD)
Individuals with Crohn’s disease or ulcerative colitis have a higher risk of developing colorectal cancer. account for 27% of melanoma cases, whereas individuals with few common nevi (0 to 10) account for only 4% of melanoma cases.
- Ulcerative colitis is a clear risk factor for colon cancer. About 1% of colorectal cancer patients have a history of chronic ulcerative colitis. The risk for the development of cancer in these patients varies inversely with the age of onset of the colitis and directly with the extent of colonic involvement and duration of active disease.
- Crohn disease: Patients with colorectal Crohn disease are at 1.5 to 2 times increased risk for colorectal cancer. The risk is less than that of those with ulcerative colitis.
Diet
Populations with high intake of fat, higher caloric intakes, and low intake of fiber (fruits, vegetables, and grains) characterized as a westernized diet tend to have an increased risk for colorectal cancer in most but not all studies.
Symptoms of Colorectal Cancer
In its early stages, colorectal cancer may not produce any noticeable symptoms. However, as cancer grows and spreads, it can cause several symptoms. Here are some of the common symptoms of colorectal cancer –
- Changes in bowel habits, such as diarrhoea or constipation last for more than a few days.
- Blood in the stool or rectal bleeding, may appear as bright red or very dark.
- Abdominal pain or discomfort, including cramping or bloating.
- Unexplained weight loss.
- Fatigue or weakness.
- Narrow stools.
- Feeling like you need to have a bowel movement that is not relieved by doing so.
- Nausea or vomiting.
These symptoms can be caused by other conditions, such as haemorrhoids or inflammatory bowel disease. However, if you experience any of these symptoms, especially if they persist for more than a few days, you should consult your healthcare provider for an evaluation. Early detection of colorectal cancer is key to successful treatment and improved outcomes. Screening tests such as colonoscopy can help detect cancer at an early stage, even before symptoms appear.
Diagnoses of Colorectal Cancer
The diagnosis of colorectal cancer typically involves several steps, including –
Biopsy confirmation:
Biopsy confirmation of malignancy via colonoscopy or via CTguided fine-needle aspiration is important. US-guided biopsy of the liver metastases can also be diagnostic.
General evaluation:
General evaluation includes a complete physical examination with digital rectal examination, CBC, LFT, and chest imaging.
Carcinoembryonic antigen (CEA) screening:
CEA screening is recommended by the American Society of Clinical Oncology (ASCO) as a means of identifying early recurrence despite the lack of elevation in 40% of individuals with metastatic disease. A preoperative CEA can be useful as a prognostic factor in determining if the primary tumour is associated with CEA elevation. Preoperative CEA elevation implies that CEA may aid in the early identification of metastases because metastatic tumour cells are more likely to result in CEA elevation in this circumstance.
Endoscopy (or CT colonography):
Colonography is indicated to assess the entire colonic mucosa because about 3% of patients have synchronous colorectal cancers and a larger percentage have additional premalignant polyps. In patients where the initial full colonoscopy was not possible due to a distal obstruction, deserve a full evaluation after recovery from initial surgical resection.
Preventions and Treatments for Colorectal Cancer
Preventions to be considered are as follows
There are several measures that can be taken to help prevent colorectal cancer. These include –
- Periodic sigmoidoscopy or colonoscopy identifies and removes precancerous lesions (polyps) and reduces the incidence of colorectal cancer in patients who undergo colonoscopic polypectomy.
- Diets that are high in fiber and low in fat or that contain calcium supplements, or both, may deter polyp progression to cancer.
- Nonsteroidal anti-inflammatory drugs (NSAIDs): In a randomized, double-blind, placebo-controlled study of patients with familial polyposis, sulindac at a dose of 150 mg b.i.d. significantly decreased the mean number and mean diameter of polyps as compared with those in patients given placebo.
Treatments required for Colorectal Cancer
The treatment for colorectal cancer depends on several factors, including the stage of cancer, the location of the tumour, and the patient’s overall health. Here are some of the common treatments for colorectal cancer –
Surgery is the only universally accepted potentially curative treatment for colorectal cancer. Curative surgery should excise the tumour with wide margins and maximize regional lymphadenectomy such that at least 12 lymph nodes are available for pathologic evaluation. For lesions above the rectum, resection of the tumour with a minimum 5-cm margin of the grossly negative colon is considered adequate, although the ligation of vascular trunks required to perform an adequate lymphadenectomy may necessitate larger bowel resections. Laparoscopic colectomy approaches have been developed and appear to be equally effective staging and therapeutic approaches to open colectomy, with modest decreases in hospital stay and pain medication use and improved cosmetic results. Subtotal colectomy and ileoproctostomy may be advisable for patients with potentially curable colon cancer and with adenomas scattered in the colon or for patients with a personal history of prior colorectal cancer or a family history of colorectal cancer in first-degree relatives.
- Arterial supply. Excision of a tumour in the right colon should include the right branch of the middle colic artery as well as the entire ileocolic and right colic artery. Excision of a tumour at the hepatic or splenic flexure should include the entire distribution of the middle colic artery.
- Avoidance of permanent colostomy in middle and low rectal cancers has been encouraged by the emergence of new surgical stapling techniques as well as the use of preoperative chemotherapy and radiation to shrink tumours prior to resection.
- Rectal tumours may be treatable by primary resection and more distal anastomosis, usually without even a temporary (anastomosisprotective) colostomy, if the lower edge is above 5 cm from the anal verge.
Chemotherapy is the use of drugs to destroy cancer cells, usually by keeping the cancer cells from growing, dividing, and making more cells.
A chemotherapy regimen, or schedule, usually consists of a specific number of cycles given over a set period of time. A patient may receive 1 drug at a time or a combination of different drugs given at the same time.
Chemotherapy may be given after surgery to eliminate any remaining cancer cells. For some people with rectal cancer, the doctor will give chemotherapy and radiation therapy before surgery to reduce the size of a rectal tumour and reduce the chance of cancer returning.
Many drugs are approved by the U.S. Food and Drug Administration (FDA) to treat colorectal cancer in the United States. Your doctor may recommend 1 or more of them at different times during treatment. Sometimes these are combined with targeted therapy drugs.
Radiation therapy is the use of high-energy x-rays to destroy cancer cells. It is commonly used for treating rectal cancer because this kind of tumor tends to recur near where it originally started. A doctor who specializes in giving radiation therapy to treat cancer is called a radiation oncologist. A radiation therapy regimen, or schedule, usually consists of a specific number of treatments given over a set period of time.
- External-beam radiation therapy: External-beam radiation therapy uses a machine to deliver x-rays to where the cancer is located. Radiation treatment is usually given 5 days a week for several weeks. It may be given in the doctor’s office or at the hospital.
- Stereotactic radiation therapy: Stereotactic radiation therapy is a type of external-beam radiation therapy that may be used if colorectal cancer has spread to the liver or lungs. This type of radiation therapy delivers a large, precise radiation dose to a small area. This technique can help save parts of the liver and lung tissue that might otherwise have to be removed during surgery. However, not all cancers that have spread to the liver or lungs can be treated in this way.
- Radiation therapy for rectal cancer: For rectal cancer, radiation therapy may be used before surgery, called neoadjuvant therapy, to shrink the tumour so that it is easier to remove. It may also be used after surgery to destroy any remaining cancer cells. Both approaches have worked to treat this disease. Chemotherapy is often given at the same time as radiation therapy to increase the effectiveness of the radiation therapy. This is called chemoradiation therapy.
For colorectal cancer, the following targeted therapies may be options.
1. Anti-angiogenesis therapy: Anti-angiogenesis therapy is focused on stopping angiogenesis, which is the process of making new blood vessels. Because a tumour needs the nutrients delivered by blood vessels to grow and spread, the goal of anti-angiogenesis therapies is to “starve” the tumour.
2. Epidermal growth factor receptor (EGFR) inhibitors. Researchers have found that drugs that block EGFR may be effective for stopping or slowing the growth of colorectal cancer.
- Cetuximab (Erbitux)
- Panitumumab (Vectibix)
3. HER2-targeted therapy: Some tumors express a protein called HER2 that can be targeted by specific medications. If this happens, the cancer is called HER2-positive. For people with HER2-positive advanced colorectal cancer, treatment with a combination of tucatinib (Tukysa) and trastuzumab (Herceptin and other brand names) may be an option. This combination may only be used if there are no mutations in the RAS gene, surgery is not an option, and chemotherapy has stopped working and/or caused side effects that require stopping treatment.
4. Combined targeted therapies: Some tumors have a specific mutation, called BRAF V600E, that can be detected by an FDA-approved test. A class of targeted treatments called BRAF inhibitors can be used to treat tumors with this mutation. A combination using the BRAF inhibitor encorafenib (Braftovi) and cetuximab may be used to treat people with metastatic colorectal cancer with this mutation who have received at least 1 previous treatment.
Immunotherapy uses the body’s natural defences to fight cancer by improving your immune system’s ability to attack cancer cells.
Checkpoint inhibitors are an important type of immunotherapy used to treat colorectal cancer.
- Pembrolizumab (Keytruda): Pembrolizumab targets PD-1, a receptor on tumor cells, preventing the tumor cells from hiding from the immune system. Pembrolizumab is used to treat unresectable or metastatic colorectal cancers that have a molecular feature called microsatellite instability (MSI-H) or mismatch repair deficiency (dMMR) (see Diagnosis). Unresectable means surgery is not an option.
- Nivolumab (Opdivo): Nivolumab is used to treat people who are 12 or older and have MSI-H or dMMR metastatic colorectal cancer that has grown or spread after treatment with chemotherapy with a fluoropyrimidine (such as capecitabine and fluorouracil), oxaliplatin, and irinotecan.
- Denvax Immunotherapy: Denvax is a treatment known as cancer immunotherapy. It boosts the immune system to fight against cancer, mostly solid tumours. Denvax is targeted therapy and comes under the 4th modality of cancer treatment called cancer Immunotherapy.
Dendritic cells are cells of the immune system that help in the fight against cancer. Denvax treatment is customized dendritic cell-based cancer immunotherapy. Denvax shows the most promise at preventing a recurrence of cancer after surgery, chemotherapy or radiation because the immune system will need to recognize and attack a smaller number of cancer cells.
- Dostarlimab (Jemperli): Dostarlimab is a PD-1 immune checkpoint inhibitor. It may be used to treat recurrent or metastatic colorectal cancers that have dMMR.
- Nivolumab and ipilimumab (Yervoy) combination: This combination of checkpoint inhibitors is approved to treat patients who are 12 or older and have MSI-H or dMMR metastatic colorectal cancer that has grown or spread after treatment with chemotherapy with a fluoropyrimidine, oxaliplatin, and irinotecan.
References:
- Manual of Clinical Oncology by Bartosz Chmeilowski and Mary Territo
- cancer.net
