What Are the Causes of Cervical Cancer?

Cervical cancer is the most common gynecological malignancy. Carcinoma in situ has a high incidence of 30 to 35 years of age, and invasive cancer of 45 to 55 years of age. In recent years, its incidence has become younger. The widespread application of cervical cytology screening in recent decades has enabled early detection and treatment of cervical cancer and precancerous lesions, and the incidence and mortality of cervical cancer have decreased significantly.

Basic Information

English name: cervical cancer
Visiting department: Obstetrics and Gynecology
Multiple groups: Carcinoma in situ is 30 to 35 years old, and invasive cancer is 45 to 55 years old

Common causes: HPV infection, multiple sexual partners, young primiparous age, multiple pregnancy and multiple births, C. trachomatis, herpes simplex virus type II, trichomoniasis, smoking
Common symptoms: Early symptoms are often asymptomatic, and vaginal bleeding and drainage may develop

Causes of cervical cancer

The cause may be related to the following factors:

Virus infection

Persistent high-risk HPV infection is a major risk factor for cervical cancer. More than 90% of cervical cancers are associated with high-risk HPV infection.

2. Sexuality and number of births

Multiple sexual partners, first sexual life <16 years old, young primiparous age, multiple pregnancy and childbirth are closely related to the occurrence of cervical cancer.

3. Other biological factors

Chlamydia trachomatis, herpes simplex virus type II, trichomoniasis and other pathogens have synergistic effects in the pathogenesis of cervical cancer caused by high-risk HPV infection.

4. Other behavioral factors

Smoking as a co-factor of HPV infection can increase the risk of cervical cancer. In addition, malnutrition and poor sanitary conditions can also affect the occurrence of diseases.

Clinical manifestations of cervical cancer

Early cervical cancer often has no obvious symptoms and signs, and the cervix may be smooth or difficult to distinguish from cervical ectopic epithelium. Patients with cervical canal type are easily missed or misdiagnosed due to the normal appearance of the cervix. As the disease progresses, the following manifestations can occur:

Symptoms

(1) Vaginal bleeding is mostly contact bleeding in the early stages; irregular vaginal bleeding in the middle and late stages. The amount of bleeding varies according to the size of the lesion, the invasion and interstitial blood vessels. If it invades the large blood vessels, it can cause major bleeding. Younger patients can also show prolonged menstrual periods and increased menstrual flow; older patients often have irregular vaginal bleeding after menopause. Generally, the exogenous type has symptoms of vaginal bleeding earlier, and the amount of bleeding is large; the endogenous type appears later.

(2) Vaginal drainage Most patients have vaginal drainage, the liquid is white or bloody, and it can be thin like water or rice-like or smelly. Advanced patients with cancerous tissue necrosis and infection may have a large amount of rice soup-like or purulent stench leucorrhea.

(3) Advanced symptoms Different secondary symptoms appear according to the extent of cancer involvement. Such as frequent urination, urgency, constipation, swelling and pain in the lower limbs, etc .; When the tumor compresses or involves the ureter, it can cause ureteral obstruction, hydronephrosis and uremia; in the later stage, there may be symptoms of systemic failure such as anemia and cachexia.

2. Signs

Carcinoma in situ and minimally invasive carcinoma may have no obvious gross lesions, and the cervix may be smooth or only columnar epithelial ectopic. Different signs may appear as the disease progresses. Exogenous cervical cancer can be seen with polyps and cauliflower-like vegetation, often accompanied by infection, and the tumor is brittle and easy to bleed. Endogenous cervical cancer is characterized by cervical hypertrophy, firmness, and cervical canal enlargement; advanced cancer tissue necrosis and shedding, forming ulcers or Hollow with stench. When the vaginal wall is affected, it can be seen that the vegetation grows on the vaginal wall or the vaginal wall is hardened; when the parauterine tissues are involved, the double and triple diagnosis can touch the thickened, nodular, hard or frozen frozen tissues Pelvic.

3. Pathological type

There are three types of squamous cell carcinoma, adenocarcinoma, and adenosquamous carcinoma.

(1) Squamous cell carcinoma is classified into grade III according to histological differentiation. Grade is highly differentiated squamous cell carcinoma, grade is moderately differentiated squamous cell carcinoma (non-keratinizing large cell type), grade is poorly differentiated squamous cell carcinoma (small cell type), and mostly undifferentiated small cells.

(2) Adenocarcinoma accounts for 15% to 20% of cervical cancer. There are two main types of histology. Mucinous adenocarcinoma: Most commonly, it originates from columnar mucinous cells of the cervical canal. Glandular structures are seen under the microscope. Glandular epithelial cells are multi-layered, with atypical dysplasia. See mitotic figures. Can be divided into high, medium and poorly differentiated adenocarcinoma. Malignant adenoma: It is also called slightly adenocarcinoma, which is a highly differentiated cervical canal mucosal adenocarcinoma. There are many cancerous glands, varying in size and morphology, and they protrude into the deep layer of human cervical interstitium. The glandular epithelial cells have no atypia and often have lymph node metastasis.

(3) Adenosquamous carcinoma accounts for 3% to 5% of cervical cancer. It is formed by the differentiation and development of reserve cells into glandular cells and squamous cells at the same time. Cancerous tissue contains two components of adenocarcinoma and squamous cell carcinoma.

4. Transfer route

Mainly direct spread and lymphatic metastasis, hematogenous metastasis is rare.

(1) Direct spread is most common, with local infiltration of cancerous tissues and spread to adjacent organs and tissues. The vaginal wall is often involved, and the cervical cavity is rarely affected by the cervical canal. The spread of cancerous lesions to the sides can involve the cervical and paravaginal tissues up to the pelvic wall. When the cancerous lesions compress or invade the ureter, it can cause ureteral obstruction and kidney disease water. The late stage can spread forward and backward and invade the bladder or rectum, forming a bladder vaginal fistula or rectal vaginal fistula.

(2) Lymphatic metastasis: After local infiltration of the cancerous foci, it invades the lymphatic vessels to form tumor plugs, which drain into the local lymph nodes with the drainage of lymphatic fluid and spread within the lymphatic vessels. The primary lymphatic metastasis group included parauterine, paracervix, obturator, intra-condylar, extra-condylar, common iliac, and pre-condylar lymph nodes; the secondary group included deep groin, superficial lymph nodes, and paraabdominal lymph nodes.

(3) Hematogenous metastasis is rare, and it can be metastasized to lung, liver or bone in the later stage.

Cervical cancer screening

Cervical smear cytology

It is the main method for cervical cancer screening, and it should be obtained in the cervical transformation area.

2. Cervical iodine test

Normal cervical and vaginal squamous epithelium is rich in glycogen, and brown or dark brown after iodine solution staining. The non-stained area indicates that the epithelium lacks glycogen and may have lesions. Taking biopsies in areas not stained with iodine can improve the diagnosis rate.

3. Colposcopy

Cervical scrape cytology examination of Pap and above, TBS classification as squamous intraepithelial neoplasia, should be selected under the colposcopy observation of suspicious cancerous areas for cervical biopsy.

4. Cervical and cervical canal biopsies

It is a reliable basis for the diagnosis of cervical cancer and cervical precancerous lesions. The tissues taken should include interstitial and adjacent normal tissues. The cervical smear is positive, but the cervix is smooth or the cervical biopsy is negative. The cervical canal should be scraped with a small curette, and the scraped material will be sent for pathological examination.

5. Cervicotomy

Applicable to those who have multiple positive cervical smears and negative cervical biopsy; or cervical biopsy for cervical intraepithelial neoplasia, which needs to exclude invasive cancer. Cold knife resection, circular electric resection or condensing electric knife resection can be used.

Cervical cancer diagnosis

The diagnosis can be confirmed based on medical history, symptoms, gynecological examination and / or colposcopy and cervical tissue biopsy.

Differential diagnosis of cervical cancer

The diagnosis is mainly based on cervical biopsy. Attention should be paid to the identification of various cervical lesions with similar clinical symptoms or signs. include:

Benign cervical lesions

Cervical columnar epithelium, cervical polyps, cervical endometriosis, and cervical tuberculosis ulcers;

2. cervical benign tumor

Cervical submucosal fibroids, cervical canal fibroids, cervical papilloma, etc .;

3. Cervical malignancy

Primary malignant melanoma, sarcoma and lymphoma, metastatic cancer, etc.

Cervical Cancer Treatment

According to clinical staging, patient age, fertility requirements, general conditions, medical technology level and equipment conditions, comprehensive consideration should be made to develop an appropriate individualized treatment plan. A comprehensive treatment plan with surgery and radiation as the mainstay and chemotherapy as the supplementary is adopted.

Surgical treatment

Surgery is mainly used in patients with early cervical cancer.

Commonly used procedures are: total hysterectomy; subextensive hysterectomy and pelvic lymph node dissection; extensive total hysterectomy and pelvic lymph node dissection; paraabdominal aortic lymphectomy or sampling. The ovaries of young patients can be preserved normally. For young patients who require reproductive function, it is a particularly early feasible cervical cone resection or radical cervical resection. Different surgical methods are selected according to the different stages of the patient.

2. Radiation therapy

Applicable to: middle-to-late stage patients; early patients whose general conditions are not suitable for surgery; preoperative radiotherapy of large cervical lesions; adjuvant treatment of high risk factors found after pathological examination after surgery

3. chemotherapy

It is mainly used for patients with advanced or recurrent metastasis. In recent years, surgery combined with preoperative neoadjuvant chemotherapy (intravenous or arterial infusion chemotherapy) has been used to reduce tumor lesions and control subclinical metastases. It is also used for radiosensitization. Commonly used chemotherapy drugs are cisplatin, carboplatin, paclitaxel, bleomycin, ifosfamide, and fluorouracil.

Cervical cancer prognosis

It is closely related to clinical stage and pathological type. Patients with lymph node metastasis have a poor prognosis. Cervical adenocarcinoma is susceptible to lymphatic metastasis at an early stage and the prognosis is relatively poor. All in all, early treatment has a better prognosis.

Cervical cancer prevention

1. Popularize anti-cancer knowledge, carry out sexual health education, and promote late marriage and less childcare.

2. Pay attention to high-risk factors and high-risk groups, and seek medical attention in a timely manner.

3. Early detection and diagnosis of cervical intraepithelial neoplasia, blocking the occurrence of cervical invasive carcinoma.

4. Improve and play the role of women's cancer prevention and health care network, carry out cervical cancer screening, and achieve early detection, early diagnosis and early treatment.