- Rectal cancer causes
- Rectal cancer diagnostics
- Rectal cancer stages
- Condition symptoms
- Therapy tactics
- What operations are performed for rectal cancer?
- What is the treatment for stages 1, 2 and 3 of rectal adenocarcinoma?
- What tactics is adopted for stage 4 cancer?
- What chemotherapy is applied for rectal adenocarcinoma?
- Targeted adenocarcinoma therapy
Rectal cancer belongs to tumors the diagnostics of which requires just a routine examination. Unlike other colon tumors, it is sensitive to irradiation and chemotherapy, but the best result is achieved only when these are combined with surgery. As a rule, the tumor occurs in the middle part of the gut called ampulla.
Rectal cancer causes
The main risk factor are polyps, yet not all, but those having a villous structure. In addition, the probability of a polyp malignization is related to its size and duration of existence, the larger the size, the higher the likelihood of cancer, so all polyps must be removed.
Adenocarcinoma more often develops in the peoples of East Asia, and it is assumed that there is a close relationship with their nutrition and genetics. For some reason, the condition is more common in men, but heredity has no significant role.
Rectal cancer diagnostics
Rectal cancer is recognized as a condition that can be detected very early, by visual localization of a malignant tumor. Detection of rectal pathology does not require complex equipment, the surgeon just needs to feel the intestine with a finger from the inside. Digital examination is included in the standard surgical technique, but it is performed very rarely, therefore, the condition is infrequently detected at an early stage.
This cancer manifests itself in unpleasant symptoms, usually a change in defecation character, pain and bleeding, but at the beginning of the malignant neoplasm development there are no clinical signs.
Rectal cancer stages
Previously, the stage of cancer was determined by the tumor size, but it turned out that much more important for the prognosis, and hence for the choice of optimal treatment, are the depth of cancer cells penetration into the intestine wall and existence of metastases in nearby lymph nodes. If the tumor has not yet involved the lymph nodes in the process, then this is early cancer stage I and II.
- At stage I, the tumor is limited to the rectal mucosa.
- Its growth through the entire intestinal wall, but without going beyond the organ limits, takes the process to stage II.
- Metastases in the lymph nodes near the intestine at any size of the primary tumor change the stage to III.
- Stage IV is diagnosed only with metastases in other organs, most often in the liver and lungs.
A very important prognostic sign is the degree of neoplasm malignancy determined by maturity of the cells. The more primitive a cell is, the more aggressive it multiplies. The cancer of the most primitive cells is called undifferentiated, and it quickly metastasizes. The neoplasm with a high differentiation has the lowest malignancy and the best prognosis. Accordingly, a moderately differentiated cancer has an average degree of aggressiveness.
The main function of the rectum is the formation and excretion of fecal material. Therefore, defecation disorders are the first symptoms of the disease. It may be constipation or diarrhea, at first the symptoms are transient, but with the growth of the neoplasm, the feces of normal consistency become very rare.
Often there are false urges, when with a small amount of feces there is an overwhelming desire to evacuate one’s bowels, which is called «rectal spittle». Very often, after defecation there is no feeling of complete emptying of the intestine, if the cancer is located near the anus, then during the bowel movement there is a disturbing pain.
The second sign is appearance of blood in the feces, at first only by streaks, then clots are released, sometimes with an admixture of mucus. The presence of mucus without blood is not considered a sign of rectal cancer. With chronic blood loss, blood test is made for anemia, a lack of red blood cells and hemoglobin.
Intense chronic pain occurs during invasion of the entire intestine wall and involvement of the pelvic nerve plexus. If the cancer spreads to the urinary bladder, then symptoms of a cystitis resistant to standard treatment appear. When cancer invades vaginal tissues, there is pain during intercourse.
Rectal cancer progresses aggressively even with a favorable histological structure, a well differentiated adenocarcinoma. The process is prone to relapse and rapid metastasic spreading, most often to the liver and lungs. The high degree of malignancy coincides with the sensitivity to irradiation and chemotherapy, but cancer cells quickly develop resistance, that is, a
The main set of therapeutic measures can be supplemented by innovative local methods of destruction by various physical factors and targeted drugs. But with an advanced process, even the most advanced approach does not promise a complete cure, that’s why it is so important to identify the malignant process at the very beginning, preferably at the stage of a villous polyp.
The neoplasm is detected by digital examination, and an endoscopic examination called sigmoidoscopy is always performed, during which a piece of the tumor is taken for microscopy. A colonoscopy is always performed, because occurrence in the large intestine of several cancer nodules at once is rare but possible.
Before starting treatment, MRI of the lesser pelvis is performed to establish the size of the formation and involvement of the neighboring organs and tissue of the lesser pelvis.
Radical treatment of rectal cancer necessarily includes surgery. At stage 1, endoscopic surgery or the most sparing and
The scope of intervention at stage 2 depends on the localization of the tumor in the organ and its true size, a poorly differentiated adenocarcinoma requires chemotherapy. At stage 3, preventive chemotherapy is required after surgery, supplemented with irradiation.
What operations are performed for rectal cancer?
- In case of an early adenocarcinoma, an
organ-preservingendoscopic transanal resection is sufficient, when the entire malignant tumor is microsurgically removed with a small area of the intestinal wall. The cancerous lesion should be very small, not exceeding 3 cm, and should occupy no more than one third of the intestine circumference, not penetrating beyond the mucous membrane and having no signs of cell aggressiveness. If, with minimal surgery, subsequent histological examination reveals unfavorable prognostic signs, a repeated operation of a larger scope is possible.
- A rather extensive part of the organ is excised during mesorectuctomy, depending on the location of the cancer conglomerate. This resection option may be partial or total, without a temporary output of the end portion on the abdominal wall, or with an ileostomy. In the lower third of the intestine closer to the anus, a practically similar intervention is called
abdominal-analor intersphincter resection. If it is necessary to relocate the anus to the abdomen, the patency of the intestinal tube is fully restored after some time, as a rule, after completion of preventive chemotherapy.
abdominal-perinealextirpation is also still performed, when the cancerous lesion does not allow for another option, and large arrays of tissue are removed in the process of pelvic evisceration for a relapse after radical treatment. In both cases, the intestine is exteriorized on the abdominal wall, creating thus an artificial anus, and a postoperative scar remains in place of the anatomical anus.
Currently, there is a tendency to operate each patient. If the tumor is initially inoperable, then at the first stage chemoradiation treatment is performed, after which the possibility of delayed surgical treatment is discussed. As a rule, the probability of a surgical intervention is questionable in case of multiple and
What is the treatment for stages 1, 2 and 3 of rectal adenocarcinoma?
With early stage 1 cancer, endoscopic resection is applied, and most patients can be cured without any additional exposure, so no radiation or chemotherapy is performed.
With a larger lesion of the intestinal wall depth by the malignant process, but without seeding of cancer cells into peripheral lymph nodes (stage 2), a part of the organ is also resected, but widely this time, applying mesorectimectomy. If the relapse probability is low, the treatment is considered completed. In the presence of cellular signs of an unfavorable prognosis, preventive chemotherapy is perfromed for six months.
At stage 3 of adenocarcinoma, irradiation is performed before surgery. With
What tactics is adopted for stage 4 cancer?
With an initially inoperable stage 3 process, a large neoplasm impacted into the surrounding tissue,
Stage 4 is not a contraindication to surgery if it is possible to remove hepatic and pulmonary metastases, but at the first stage, up to 6 chemotherapy cycles are performed. After chemotherapy, surgery is performed with simultaneous excision of the rectal tumor and resection of metastases, or all tumors are removed in several sessions, including such innovative methods as laser or radio frequency ablation (RFA), and cryodestruction.
What chemotherapy is applied for rectal adenocarcinoma?
- For adjuvant or prophylactic chemotherapy, FOLFOX and XELOX schemes are prescribed.
- At stages 2 and 3, only tablet forms of drugs are used. The duration of preventive therapy is 6 months.
- No optimal standard options have yet been found for therapy of generalized metastatic process. There is no single strategy, different options are possible: to perform a
semi-annualcycled chemotherapy until the cancer process stabilizes and stop without resorting to chemotherapy until signs of progression appear; after 3–4 months of combined chemotherapy in any of the regimens, to continue treatment to maintain the achieved result; the third approach is to administer treatment as long as there is no severe toxicity or the patient has enough strength.
Targeted adenocarcinoma therapy
A targeted drug, unlike the one intended for chemotherapy, interrupts a certain biochemical process disrupting the reproduction of cancer cells. Cytostatic chemotherapy is enhanced by a targeted drug from the group of monoclonal antibodies, since a targeted drug alone has not shown efficacy.
With colonic cancer, a mutation of the CRAS gene is necessarily detected in the tumor; if it is not present, the use of a monoclonal antibody against the specific vascular factor EGFR is useful.
Clinical studies have demonstrated the benefit of using a progressive blocker of the cell enzyme protein kinase for advanced rectal cancer.
All antitumor drugs affect both cancer and normal cells, which is manifested by side reactions, the spectrum of which is diverse, and the intensity is individual.
This text is based on the materials of NCCN (National Cancer Comprehensive Network).
Treatment of rectal cancer is a very difficult task, where a positive result depends on the biological characteristics of the cancer cells, but the clinic’s possibilities are also important, while the national clinical recommendations make a special emphasis, because the optimal treatment of each clinical case is available only to highly qualified experts, like the ones who work in our clinic.