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Rectal Cancer

 

Surgery is a common treatment for rectal cancer. The type of operation used to remove the rectal cancer depends on the extent and location of the cancer. If the rectal cancer is located well above the anus, a low anterior resection (LAR) can be performed. This operation allows the patient to keep anal function and pass stools in a normal manner. If the rectal cancer is located close to the anus, sometimes the anus must be removed with the cancer in an operation called an abdominoperineal resection (APR). The patient must then use a colostomy bag. A colostomy is an opening where the large intestine is attached to the abdominal wall. A replaceable bag that encloses the colostomy is worn by the patient to collect stool.

 

Low Anterior Resection Surgery (LAR)

 

LAR is a common treatment for rectal cancer when the cancer is located well above the anus. During a LAR, the entire rectal cancer, adjacent normal rectal tissue and surrounding lymph nodes are removed through an incision made in the lower abdomen. After the cancer is removed, the cut ends of the rectum are sewn back together. The passage of stool from the large intestine through the anus is therefore preserved. If the cancer is lower in the rectum, the cut end of the large bowel may be attached directly to the anus, a procedure known as colo-anal anastomosis. When a colo-anal anastomosis is performed, some surgeons will create a temporary colostomy in order to protect the delicate surgical connection of the large intestine to the anus. After the patient has recovered from the surgery, the temporary colostomy is removed and stool is again passed normally through the large intestine. The colon is resewn to the anus.

 

Despite undergoing complete surgical removal of rectal cancer, some patients may experience recurrence of their cancer. It is important to realize that some patients with rectal cancer already have small amounts of cancer that have spread outside the rectum and were not removed by surgery. These cancer cells are referred to as micrometastases and cannot be detected with any of the currently available tests. The presence of these microscopic areas of cancer causes the relapses that follow treatment with surgery alone. External beam radiation therapy and chemotherapy can be used to cleanse the body of micrometastases in order to improve the cure rate achieved with surgical removal of the cancer.

 

Patients undergoing an LAR may experience lower abdominal pain after the operation. Less common complications related to surgery include bleeding, infection and temporary difficulty with emptying the bladder. Some men may experience sexual dysfunction after surgery. In-hospital death occurs after LAR in less than 5% of patients. Patients should ask their surgeon to explain the various surgical complications and their frequency of occurrence at the hospital where the surgery will be performed.

 

Abdominoperineal Resection Surgery (APR)

 

APR is a common treatment for rectal cancer when the cancer is located close to the anus. During an APR, the entire rectal cancer, adjacent normal rectum, rectal sphincter or anus, and surrounding lymph nodes are removed through an incision in the lower abdomen and the perineum (the skin around the anus). Following removal of the cancer, the incision in the perineum is sewn shut. The cut end of the large intestine is attached to an opening in the abdominal wall, called a colostomy. This opening is covered with a bag, which serves to collect stool as it passes through the large intestine and through the colostomy. In contrast to a LAR, the colostomy is permanent.

 

Many patients would like to avoid a permanent colostomy. When the rectal cancer lies close to the sphincter or anus, an APR is typically recommended. In some instances, a more limited surgery can be used to avoid a colostomy, or radiation therapy can be used to shrink the rectal cancer prior to surgery allowing the patient to maintain control of bowel function. Some small rectal cancers that lie close to the anus can be removed with less extensive surgery called a local excision. Not all patients can undergo a local excision (see Local Excision below).

 

Patients undergoing an APR may experience lower abdominal pain after the operation. Less common complications related to surgery include bleeding, infection, slow wound healing and temporary difficulty with emptying the bladder. Some men may experience sexual dysfunction after surgery. In-hospital death occurs after APR in less than 5% of patients. Patients should ask the surgeon to explain the various surgical complications and their frequency of occurrence at the hospital where the surgery will be performed.

 

Sphincter-Sparing Treatment

 

The rectal sphincter is the circular muscle that controls defecation. If damaged, patients lose control of bowel function. Sphincter-sparing treatment refers to cancer therapy that avoids removal of the anal sphincter for rectal cancers that lie close to the anus. The standard surgical procedure used to remove rectal cancer that lies close to the anus is an abdominoperineal resection (APR). Following an APR procedure, the anus is removed with the cancer, and the cut end of the large bowel is attached to the abdominal wall to form a colostomy. The colostomy is covered by a bag, which collects stool as it empties from the bowel. Because of the inconvenience of a colostomy, physicians are using sphincter-sparing treatments that allow the patient to preserve function of the anus. Sphincter-sparing treatment for rectal cancer involves limited surgery, often followed by a combination of chemotherapy and radiation therapy. The limited surgery is designed to remove the cancer and a small rim of normal bowel, but not the anus. The surgery may be performed through the anus (transanal excision) or through the coccyx (transcoccygeal) or the tailbone. A transanal excision can be performed for small cancers that lie close (within 2 inches) to the anus. Other small cancers higher in the rectum can be removed with a transcoccygeal excision.

 

Local Excision

 

Limited surgery can be performed to remove the cancer and preserve the anus and prevent the complications that may occur with more extensive LAR or APR surgeries. The limited surgery is designed to remove the cancer and a small rim of normal bowel, but not the anus. The surgery may be performed through the anus (transanal excision) or through the coccyx (transcoccygeal) or the tailbone. A transanal excision can be performed for small cancers that lie close (typically within 2 inches) to the anus. Other small cancers higher in the rectum can be removed with a transcoccygeal excision.

 

For limited surgery to be effective, the entire cancer with a rim of normal tissue must be removed. Patients with cancers that are larger, more deeply invading, or appear aggressive under the microscope are better treated with traditional surgery. In order to improve the cure rates after limited surgery alone, a combination of chemotherapy and radiation therapy is often administered for cancers that have grown into the muscular wall of the rectum.

 

Patients undergoing limited surgery may experience pain in the region of the perineum or tailbone. Less common complications related to surgery include bleeding, infection, and difficulty with healing of the rectal wall. In-hospital fatality is very rare after limited surgery.

 

Strategies to Improve Treatment

 

The progress that has been made in the treatment of rectal cancer has resulted from improved surgical techniques and the development of neoadjuvant and adjuvant treatments in patients with more advanced stages of cancer and participation in clinical trials. Future progress in the treatment of rectal cancer will result from continued participation in appropriate clinical trials.

 

Improved Sphincter-Sparing Treatments: Because of the inconvenience of a colostomy, physicians are using sphincter-sparing treatments that allow patients with low-lying rectal cancers to keep the anus. Improved methods to select patients who can be treated with limited surgery followed by adjuvant chemotherapy and radiation therapy are being developed. More aggressive use of preoperative (neoadjuvant) chemoradiation may allow more patients with larger low-lying rectal cancers a chance to maintain anal function.

 

Neoadjuvant Therapy: When rectal cancer cannot be completely removed with surgery, a patient’s chance of cure is greatly diminished. Presurgery radiation and/or chemotherapy is referred to as neoadjuvant therapy. Neoadjuvant therapy can shrink some rectal cancers and therefore allow complete surgical removal. Determining the optimal neoadjuvant chemotherapy and radiation therapy is an area of current research.

 

Radiation Therapy for Rectal Cancer

 

Radiation therapy, or radiotherapy, is a common way to treat rectal cancer. Doctors who specialize in treating cancers with radiation are known as radiation oncologists. Radiation therapy involves the use of high-energy x-rays to kill cancer cells. For many rectal cancers, radiation therapy is used after surgery to destroy any cancer cells that may remain in the area of the operation. In advanced stages of rectal cancer, radiation therapy is often given before surgery to shrink the cancer, or instead of surgery when an operation cannot be performed. Radiation therapy is also commonly given in combination with anti-cancer drugs (chemotherapy). Chemotherapy has the ability to kill cancer cells directly and make radiation therapy more effective in killing cancer cells.

 

Radiation therapy for rectal cancer is typically given by a machine that aims x-rays at the body (external beam radiation). External beam radiation therapy (EBRT) for rectal cancer is given on an outpatient basis, 5 days a week, for approximately 5 to 6 weeks. EBRT begins with a planning session, or simulation, where marks are placed on the body and measurements are taken in order to line up the radiation beam in the correct position for each treatment. A program of daily treatments is then begun where the patient lies on a couch and is treated with radiation from multiple directions to the pelvis. The radiation oncologist may perform a second planning session or simulation near the end of treatment to focus the radiation to the area where cancer cells are most likely to remain. The last 3-5 days of treatment may be directed at this area.

 

Although patients do not feel anything while receiving a radiation treatment, the effects of radiation gradually build up over time. Many patients become somewhat fatigued as treatment continues. Loose stools or diarrhea are also common. Urination may become more frequent or uncomfortable. Some patients may experience loss of pubic hair or irritation of the skin. When radiation therapy is given with 5-fluorouracil chemotherapy, diarrhea can be worse. In a small percentage of patients, an obstruction or blockage in the small bowel can occur, which may require hospitalization or even abdominal surgery to relieve. Radiation therapy can also cause chronic changes in bowel function, resulting in loose stools and inflammation of the prostate when severe.

 

Some radiation oncology centers have special treatment equipment for certain circumstances. For small early cancers, a focused radiation beam can be aimed directly at the cancer in the rectum. Intra-operative radiation therapy (IORT) refers to treatment in a specially equipped operating room where a single dose of radiation is given during the surgery. The radiation doctor is able to see the area being treated directly and move sensitive normal structures, such as the small bowel, away from the radiation beam. IORT is usually administered when surgery is being performed for locally extensive cancer or stage II-IV cancer that has recurred in the pelvis.

 

Strategies to Improve Treatment

 

The progress that has been made in the treatment of rectal cancer has resulted from improved development of radiation treatments and surgical techniques and participation in clinical trials. Future progress in the treatment of rectal cancer will result from continued participation in appropriate clinical trials. Currently, there are several areas of active exploration aimed at improving radiation treatment of rectal cancer.

 

Newer Radiation Techniques: External Bean Radiation Therapy (EBRT) can be delivered more precisely to cancer-containing areas by using a special CT scan and targeting computer. This capability is known as three-dimensional conformal radiation therapy, or 3D-CRT. The use of 3D-CRT appears to reduce the chance of injury to nearby normal body structures, such as the bladder or rectum. Since 3D-CRT can better target the area of cancer, radiation oncologists are evaluating whether higher doses of radiation can be given safely with greater cancer cures.

 

Newer Radiation Machines: Most EBRT uses high energy x-rays to kill cancer cells. Some radiation oncology centers use different types of radiation, which require special machines to generate. These different types of radiation, such as protons or neutrons, appear to kill more cancer cells with the same dose. Combining protons or neutrons with conventional x-rays is one method of radiation therapy being evaluated in clinical trials.

 

New Radiation Therapy Modalities: Intraoperative radiation therapy (IORT) is given in specially-equipped operating rooms to deliver a single dose of radiation directly to the area of surgery. The radiation doctor is able to see the area being treated directly and move sensitive normal structures, such as the small bowel, away from the radiation beam.

 

Neoadjuvant Therapy: When rectal cancer cannot be completely removed with surgery, a patient’s chance of cure is greatly diminished. Presurgery radiation and/or chemotherapy is referred to as neoadjuvant therapy. Neoadjuvant therapy can shrink some rectal cancers and therefore allow complete surgical removal. Determining the optimal neoadjuvant chemotherapy and radiation therapy is an area of current research.

 

Recurrent Rectal Cancer

 

Recurrent rectal cancer is cancer that has returned or progressed following initial treatment with surgery, radiation therapy and/or chemotherapy.

 

A variety of factors ultimately influence a patient’s decision to receive treatment of cancer. The purpose of receiving cancer treatment may be to improve symptoms through local control of the cancer, increase a patient’s chance of cure, or prolong a patient’s survival. The potential benefits of receiving cancer treatment must be carefully balanced with the potential risks of receiving cancer treatment.

 

The following is a general overview of the treatment of recurrent rectal cancer. Circumstances unique to your situation and the prognostic factors of your cancer may ultimately influence how these general treatment principles are applied. The information on this Web site is intended to help educate you about your treatment options and to facilitate a mutual or shared decision-making process with your treating cancer physician.

 

Most new treatments are developed in clinical trials. Clinical trials are studies that evaluate the effectiveness of new drugs or treatment strategies. The development of more effective cancer treatments requires that new and innovative therapies be evaluated with cancer patients. Participation in a clinical trial may offer access to better treatments and advance the existing knowledge about treatment of this cancer. Clinical trials are available for most stages of cancer. Patients who are interested in participating in a clinical trial should discuss the risks and benefits of clinical trials with their physician. To ensure that you are receiving the optimal treatment of your cancer, it is important to stay informed and follow the cancer news in order to learn about new treatments and the results of clinical trials.

 

Patients experiencing progression of rectal cancer have been perceived to have few treatment options. However, certain patients can still be cured of their cancer and others derive meaningful palliative benefit from additional treatment.

 

Treatment of Pelvic Recurrence of Rectal Cancer

 

Patients treated for rectal cancer may experience a recurrence of cancer near the original site of the cancer. Clinical studies have reported that certain patients with localized recurrence of cancer in the pelvis can undergo surgical removal of disease and be cured in approximately 10 to 20% of circumstances. Depending on the extent of recurrent disease, surgery may involve local excision with or without bowel resection, abdominoperineal resection, or pelvic exenteration (removal of most structures in the pelvis). Patients may also be treated with chemotherapy and radiation therapy.

 

Treatment of Metastatic Rectal Cancer

 

Recurrent rectal cancer may also involve distant sites in the body such as the liver or lung. When the site of metastasis is a single organ, such as the liver, and the cancer is confined to a single defined area within the organ, patients may benefit from local treatment—such as surgery—directed at that single site of recurrence or metastasis. This local treatment may be accompanied by systemic (whole-body) treatment such as chemotherapy. When cancer is more extensive and surgery is not possible, systemic therapy is the primary approach to treatment.

 

Treatment of the Liver:

 

When the cancer has spread only to the liver and it’s possible to completely surgically remove all liver metastases, surgery is the preferred treatment. Although surgery offers some patients the chance for a cure, a majority of patients with liver metastases are not candidates for surgery because of the size or location of their tumours or their general health. Some of these patients may become candidates for surgery if initial treatment with chemotherapy shrinks the tumours sufficiently. If the tumours continue to be impossible to remove surgically, other liver-directed therapies may be considered. These other therapies include radiofrequency ablation (use of heat to kill cancer cells), cryotherapy (use of cold to kill cancer cells), delivery of chemotherapy directly to the liver, and radiation therapy. Relatively little information is available from clinical trials about the risks and benefits of these other approaches, but they may benefit selected patients.1

 

Systemic Treatments:

 

Several different chemotherapy regimens are available, and the choice of which to use will depend on factors such as your health and previous treatment history. In some cases, chemotherapy can shrink the cancer enough that initially inoperable cancer becomes possible to surgically remove.

 

Chemotherapy may be given in combination with other drugs known as targeted therapies. Targeted therapies are anticancer drugs that interfere with specific pathways involved in cancer cell growth or survival. Some targeted therapies block growth signals from reaching cancer cells; others reduce the blood supply to cancer cells; and still others stimulate the immune system to recognize and attack the cancer cell. Depending on the specific “target”, targeted therapies may slow cancer cell growth or increase cancer cell death.

 

Targeted therapies that have shown a benefit for selected patients with metastatic colorectal cancer include Avastin® (bevacizumab), Erbitux® (cetuximab), and Vectibix® (panitumumab). Avastin blocks a protein (VEGF) that plays a key role in the development of new blood vessels. By blocking VEGF, Avastin deprives the cancer of nutrients and oxygen and inhibits its growth. Erbitux and Vectibix slow cancer growth by targeting a protein known as EGFR. Cancers with certain gene mutations are unlikely to respond to Erbitux or Vectibix, and tests are available to detect these mutations before treatment decisions are made.

 

If patients are experiencing symptoms from their rectal cancer, they may also receive treatments such as radiation therapy, surgery, or stenting to relieve problems such as bowel obstruction.

 

Strategies to Improve Treatment

 

While some progress has been made in the treatment of recurrent or progressive rectal cancer, the majority of patients still succumb to cancer and better treatment strategies are clearly needed. Future progress in the treatment of rectal cancer will result from continued participation in appropriate clinical trials. Patients with recurrent or progressive rectal cancer are usually included in clinical trials of colon cancer. Currently, there are several areas of active exploration aimed at improving the treatment of rectal cancer.

 

New Approaches to Treating Liver Metastases: Researchers continue to explore news ways to treat cancer that has spread to the liver. One approach that is being evaluated is radioembolization This strategy uses radioactive microspheres (small spheres containing radioactive material). The small spheres are injected into vasculature of the liver, where they tend to get lodged in the vasculature responsible for providing blood and nourishment to the cancer cells. While lodged in place, the radioactive substance spontaneously emits radiation to the surrounding cancerous area while minimizing radiation exposure to the healthy portions of the liver.2 Researchers are also exploring alternatives to radiofrequency ablation for the destruction of liver tumors, as well as new approaches to delivering chemotherapy to the liver.

 

New Chemotherapy Regimens: Development of new multi-drug chemotherapy treatment regimens that incorporate new or additional anti-cancer therapies is an active area of clinical research.

 

New Approaches to Targeted Therapy: Targeted therapies such as Avastin, Erbitux, and Vectibix already play a role in the treatment of selected patients with advanced colorectal cancer, but researchers continue to explore new targeted therapies as well as new ways of using existing drugs. Developing tests to predict which patients are most likely to respond to which drugs is also an important focus of research. Tests to identify certain gene mutations in the cancer are already available, and can help guide the use of Erbitux and Vectibix.

 

Managing Side Effects

 

Techniques designed to prevent or control the side effects of cancer and its treatments are called supportive care. Side effects not only cause patients discomfort, but also may prevent the delivery of therapy at its planned dose and schedule. In order to achieve optimal outcomes from treatment and improve quality of life, it is imperative that treatment is delivered as planned and that side effects resulting from cancer and its treatment are appropriately managed. For more information, go to Managing Side Effects.

 

Source: http://www.nfcr.org/rectal-cancer?gclid=CKvW2PaitboCFbLHtAodRFkA2g