Appendix cancer is a malignant tumor that is formed from the cells of the appendix of the caecum. It occurs primarily against the background of predisposing factors or develops with metastasis of oncopathology of another localization. The disease proceeds for a long time without clinical manifestations, typical symptoms occur in the case of appendicitis. Ultrasound, CT or MRI of the abdominal organs, histological analysis are used for diagnosis. Treatment includes radical or palliative surgery, adjuvant chemotherapy, complex symptomatic therapy.
ICD 10
C18.1 Malignant neoplasm of the vermiform process
Meaning
Appendix cancer is one of the rarest pathologies in practical oncology. Its frequency is no more than 0.5% of all malignant neoplasms of the large intestine. According to the results of the study of the removed vermiform processes, cancerous tumors cause only 0.02% of appendectomies performed. However, the disease does not lose its relevance and requires oncological alertness from practicing surgeons who conduct an initial examination and selection of treatment tactics for patients with appendicular symptoms.
Causes
Like other types of malignant neoplasms, appendix cancer does not have exact etiological factors. The risk of developing pathology increases in patients over the age of 50 years, with a hereditary predisposition to intestinal cancer, in the presence of Crohn’s disease with intestinal lesions of the type of terminal ileitis. Additional risk factors include smoking, frequent constipation, an irrational diet with a predominance of fats and a deficiency of vegetable fiber.
A separate category is metastatic cancer of the appendix, which occurs when the primary tumor spreads from other structures of the abdominal cavity and pelvis. The defeat of the vermiform process is observed in pancreatic cancer, gastric oncopathology, ovarian tumors in women. The medical literature describes several cases of metastasis to the appendix of malignant tumors of the mammary glands in men and women.
Pathogenesis
The disease develops according to the classical laws of tumor growth, which includes 3 consecutive stages: initiation, promotion, progression. Appendix neoplasms are characterized by exophytic growth and mucus formation (in 50% of cases), which leads to blockage of the organ lumen. This creates favorable conditions for the reproduction of pathogenic pathogens and the development of an acute inflammatory process – appendicitis.
Classification
Most often, the oncopathology of the appendix is represented by epithelial tumors – carcinomas, which, according to their histological structure, are divided into adenocarcinoma, mucinous and cricoid cell carcinoma. The second group of cancer is represented by neuroepithelial tumors. In clinical oncology, a modified classification according to TNM is widely used, which divides cancer into 4 stages:
- Stage I. It is determined when the size of the primary appendicular tumor is within 2 cm and there are no metastases.
- Stage II. It is diagnosed when the cancer grows to 2-4 cm or more with its germination into the cecum or ileum.
- Stage III. It is established with a tumor larger than 4 cm, germination into the ileum and lesion of regional lymph nodes, or with invasive growth of the neoplasm into the visceral or parietal peritoneum.
- Stage IV. It is determined in the presence of distant tumor metastases, regardless of the size and degree of invasiveness of the primary focus in the appendix.
Symptoms
At the initial stages of the disease, when the tumor is small, there are no clinical manifestations. With the progression of the neoplasm, nonspecific symptoms are possible in the form of discomfort in the right iliac region, cramping pains, instability of the stool. Systemic effects of the oncological process are represented by a deterioration of appetite, a decrease in working capacity, weight loss for no apparent reason.
Acute symptoms develop when the disease is complicated by appendicitis. The main sign is pain, which primarily occurs in the projection area of the appendix, or migrates from the epigastrium, the umbilical region. After 1-2 hours from the appearance of the pain syndrome, nausea and vomiting are added. There is a delay in stool and gases, an increase in body temperature, a complete refusal of food. In the destructive form of appendicitis, the intoxication syndrome is pronounced.
Complications
The most dangerous consequence of appendix cancer is regional and distant metastases. Metastasis is caused by lymphogenic and hematogenic pathways of the spread of malignant cells. When the tumor is located in the proximal 2/3 of the process, secondary foci appear in the lymph nodes at its base and along the right colon. Neoplasms from the distal part of the organ metastasize to the mesentery lymph nodes.
Distant metastases of appendix cancer can be found in the liver and adrenal glands, in women – in the right ovary. Pathognomonic for appendicular oncopathology is metastasis to the peritoneum by the type of carcinomatosis. Patients develop pseudomyxoma of the peritoneum, the main clinical manifestation of which is ascites. With a large diameter of the primary tumor focus, mechanical intestinal obstruction is possible.
Diagnostics
Patients with pain in the area of the appendix are immediately referred to the surgeon with suspected acute appendicitis. The initial examination includes the collection of complaints and anamnesis, palpation of the abdomen to check for pathognomonic symptoms (Bartomier-Michelson, Volkovich, Voskresensky, etc.). The scope of the diagnostic program and the timing of its implementation are determined individually, taking into account the patient’s condition. The following methods are used to make a diagnosis:
- Abdominal ultrasound. The study is conducted as a screening method to confirm or exclude appendicitis, assess the condition of the right ovary in women. According to the results of echosonography, it is possible to determine non-specific signs of the inflammatory process, but it is impossible to verify the diagnosis.
- CT of the abdominal cavity. During X-ray diagnostics, an expanded and filled appendix can be detected, which is characteristic of a tumor lesion of an organ. To clarify the size and localization of the pathological focus, computed tomography is supplemented by MRI.
- Tests for cancer markers. According to the principles of oncological alertness, patients with unclear symptoms and suspected malignant tumor are prescribed studies for markers of REA, CA 19-9. An increase in these indicators is not an absolute sign of oncopathology and is used in the complex diagnosis of appendicular cancer.
- Histological examination. Morphological verification of the diagnosis is carried out after surgery based on the analysis of the removed drug. The study clarifies the cellular composition and degree of differentiation of the tumor, the distance to the proximal and distal edges of resection. According to the indications, immunohistochemical and molecular genetic clarifying analyses are performed.
Differential diagnosis
Appendix cancer is an intraoperative diagnosis, because before its surgical removal, verification of the disease is difficult due to the lack of specific criteria. Differential diagnosis of neoplasms is carried out with benign appendicular tumors, acute appendicitis, appendicular infiltrate. In women, it is necessary to exclude ovarian neoplasms and other pathologies of the reproductive system.
Treatment
Surgical treatment
All cases of appendicular cancer require surgical removal of malignated tissues. Right-sided hemicolectomy is recognized as the operation of choice. At stages II-III, when the cancer is resectable, such an intervention is radical in nature and gives chances for a relapse-free cure. In stage IV appendicular cancer, palliative interventions are indicated – the imposition of bypass anastomoses or the removal of a stoma to normalize the passage of feces through the intestine.
Adjuvant chemotherapy
Chemotherapy drugs are used as a second-line treatment in patients with inoperable forms of appendix cancer and in the presence of unfavorable prognosis factors after radical surgery. Indications for the appointment of pharmacotherapy are a low degree of cell differentiation, the presence of lymphovascular or perineural invasion, the inability to perform adequate lymph dissection. Chemotherapy is prescribed for a period of 6 months.
Symptomatic therapy
All patients with appendix cancer require a complex of supportive treatment, which is aimed at eliminating concomitant manifestations of the disease and improving the quality of life. Of particular importance is rational analgesic therapy, which in addition to analgesics may include remote irradiation and locoregional anesthesia. According to the indications, antiemetics, preparations of digestive enzymes are prescribed.
Prognosis and prevention
After radical hemicolectomy with lymph node dissection, the 5-year survival rate is 60%. Patients are monitored dynamically with visits to an oncologist every 3-6 months during the first 2 years from the end of treatment, then, in the absence of relapses, the schedule of examinations is set individually. Taking into account the polyetiology and complex pathogenesis of appendicular oncopathology, effective preventive measures have not been developed.