The treatment for rectal cancer depends on the location and extent of the tumor. The goals of treatment are to cure the malignancy and to do so without a permanent colostomy. Early-stage rectal cancers may be treated either with endocavitary irradiation alone or transanal excision. Tumors that may be somewhat less favorable are often treated with a transanal excision combined with either preoperative or postoperative radiation therapy. More advanced rectal cancers require removal of part or all of the rectum. If at all possible, only part of the rectum is removed and a permanent colostomy is avoided. Often, advanced tumors require adjuvant radiation therapy combined with fluorouracil (5-FU) chemotherapy to reduce the risk of recurrent cancer in the pelvis and improve the chance of survival.
Before any treatment is started, the recommended treatment, the reasons it is recommended, the procedures to be carried out, the expected or possible side effects or complications, and the expected benefits are all explained to the patient and family. The patient must give permission for treatment, based on this knowledge (“informed consent”), before treatment is given.
Radiation Therapy for Lower GI Cancers – An Overview
Radiation therapy is more effective and better tolerated if given before the operation. Treatments usually are given once a day, 5 days a week, over approximately 5 to 6 weeks. The treatments tend to be well tolerated, with side effects such as minimal diarrhea and/or burning with urination. The surgery in these situations generally takes place approximately a month after completion of external-beam radiation therapy. If at the time of the operation it appears that there may be areas at high risk for tumor remaining, it is possible to perform intraoperative brachytherapy where catheters are placed into the tumor bed and then afterloaded with radioactive isotopes. This provides a boost dose of radiation to the tumor bed without exceeding the radiation tolerance of the small intestine, thus reducing the risk of a complication such as a bowel obstruction.
The chance of cure is approximately 90% for early-stage rectal cancers, 60-70% for moderately advanced rectal cancers, and approximately 20% for advanced, unresectable rectal cancers that are fixed to structures that are not removable, such as the side walls of the pelvis or the upper part of the sacrum.
Carcinoma of the esophagus
Carcinoma of the esophagus may be treated either with surgery or with radiation therapy combined with chemotherapy. The combination of radiation therapy and chemotherapy is more effective than radiation therapy alone. The advantage of surgery compared with radiation therapy and chemotherapy is that there is less likely to be a stricture in the esophagus that could cause swallowing problems after successful treatment. The disadvantage is that a major operation is required.
Radiation Therapy for Upper GI Cancers – An Overview
The optimal treatment at this time appears to be the combination of preoperative chemotherapy and irradiation to facilitate tumor regression followed by esophagectomy (surgical removal of the esophagus) and reconstruction, usually with a gastric transposition (suturing the stomach to the hypopharynx in the neck). This provides a good chance of cure with a relatively low risk of serious complications.
Before any treatment is started, the recommended treatment, the reasons it is recommended, the procedures to be carried out, the expected or possible side effects or complications, and the expected benefits are all explained to the patient and family. The patient must give permission for treatment, based on this knowledge (“informed consent”), before treatment is given.
The radiation is given once a day, 5 days a week, for 25 treatments over 5 weeks. The chemotherapy usually consists of two cycles of fluorouracil (5-FU) and cisplatin during the first and fifth weeks of radiation therapy. The surgery is performed one month after the chemotherapy and radiation therapy, and should be performed by a surgeon experienced with esophagectomies so as to reduce the risk of major complications.
Carcinoma of the pancreas
The mainstay of treatment for cancers of the pancreas is surgery. Radiation therapy may be used alone for pancreatic cancer or in combination with surgery as well as chemotherapy. Radiation therapy may be given either before or, more commonly, after surgery in the event of close margins or positive nodes to reduce the chance of recurrence in the pancreatic area. In the event that resection of the pancreatic cancer is not feasible, radiation therapy may also be given with chemotherapy to alleviate the symptoms caused by the cancer. Radiation therapy alone, or combined with chemotherapy, is unlikely to permanently eradicate an unresectable pancreatic cancer.
Before any treatment is started, the recommended treatment, the reasons it is recommended, the procedures to be carried out, the expected or possible side effects or complications, and the expected benefits are all explained to the patient and family. The patient must give permission for treatment, based on this knowledge (“informed consent”), before treatment is given.
Biliary tract cancer
The most effective treatment for biliary cancer is surgery. Radiation therapy is sometimes given after surgery in the event of close margins or positive nodes. If the cancer is not resectable, radiation therapy may be given with a combination of external beam radiation followed by a boost dose from intracavitary high-dose-rate brachytherapy, which gives a high dose of radiation therapy to the tumor from within the bile duct.
Before any treatment is started, the recommended treatment, the reasons it is recommended, the procedures to be carried out, the expected or possible side effects or complications, and the expected benefits are all explained to the patient and family. The patient must give permission for treatment, based on this knowledge (“informed consent”), before treatment is given.
Although the likelihood of cure with radiation therapy alone is relatively low, the probability of significant palliation is fairly high.
Anal cancer
Squamous cell carcinoma of the anal canal has been treated in the past by an operation to remove the anus and rectum, requiring a permanent colostomy. In recent years, this operation has been supplanted by radiation therapy. The odds of cure are essentially the same for either surgery or radiation therapy, and radiation therapy has the advantage of preserving the anus and rectum, thus avoiding a colostomy.
Before any treatment is started, the recommended treatment, the reasons it is recommended, the procedures to be carried out, the expected or possible side effects or complications, and the expected benefits are all explained to the patient and family. The patient must give permission for treatment, based on this knowledge (“informed consent”), before treatment is given.
Radiation is given once daily, 5 days a week, for approximately 6 to 6½ weeks. The treatment is usually combined with chemotherapy for patients who have more advanced cancers. The chemotherapy is usually either fluorouracil (5-FU) combined with either mitomycin C or cisplatin. The chance of cure with a combination of chemotherapy and radiation therapy is approximately 75% to 80%. Cure rates are higher for earlier stage, T1 and T2 cancers and somewhat lower for patients with more advanced disease.
Squamous cell carcinoma of the anal margin (that is, the perianal skin) may be treated either with a local excision or limited-field irradiation if the tumor is small (stage T1) and the cancer cells are well to moderately differentiated. Because larger cancers, 2 to 4 cm in maximum diameter, have an increased risk of spread to the inguinal lymph nodes, both the primary cancer and the inguinal nodes are treated with irradiation. Patients with more advanced cancers (stages T3 or T4) or with lymph nodes known to contain cancer are treated with irradiation and chemotherapy, employing the same techniques used for patients with anal canal cancers.