1.1 About cervical cancer
Cervical cancer is one of the most common female cancers in Hong Kong. In 2016, there were 510 newly diagnosed cases of cervical cancer.
Early-stage cervical cancer can have no clinical symptoms at all, and without cancer screening, it may not be detected in a timely manner. If left untreated, cervical cancer can progress and even become a life-threatening, invasive cancer.
Regular cervical screening is crucial because early-stage cervical abnormalities can be detected through cervical cell examinations. Early detection and appropriate treatment can significantly improve the cure rate and prognosis for cervical cancer patients.
1.2 Types of cervical cancer
Cervical cancer is mainly classified into two major types based on the pathological characteristics of cancerous cells: squamous cell carcinoma and adenocarcinoma. Squamous cell carcinoma is the most common type, although sometimes squamous cell carcinoma and adenocarcinoma can coexist. Other rarer types of cervical cancer include small cell carcinoma.
1.3 Case of cervical cancer
The main cause of cervical cancer is the Human Papillomavirus (HPV). Research has shown that approximately 70% of cervical cancer cases are caused by HPV. There are over a hundred types of HPV, with types 16 and 18 being high-risk types directly associated with cervical cancer. Genital HPV is primarily transmitted through sexual contact, and the virus can reside in the cervix, vagina, penis, anus, and even the oral and throat areas. Most carriers of the virus do not exhibit any symptoms.
However, if the cervical cells continue to be affected by HPV, there is a possibility of cervical cell changes leading to Cervical Intra-epithelial Neoplasm (CIN). Cervical intraepithelial neoplasia is classified into three stages: CIN I – III, with the staging based on the thickness of the cervical intraepithelial neoplasm. If left untreated, CIN III, the third stage, may progress to invasive cervical cancer.
In addition to HPV, the following risk factors also increase the risk of developing cervical cancer:
- Smoking
- Early initiation of sexual activity
- Frequent sexual intercourse
- Having multiple sexual partners or having a partner with multiple sexual partners
- History of other sexually transmitted infections such as Chlamydia and Herpes
- Long-term use of oral contraceptives, exceeding five years
- Having an immunodeficiency condition such as chronic kidney disease or HIV/AIDS
- Having given birth three or more times, with the first pregnancy occurring at a young age.
1.4 Symptoms of cervical cancer
In general, early-stage cervical cancer does not present any symptoms. Most early-stage cervical cancer cases are incidentally detected during cervical screening when abnormal cells are found. If abnormal cells are detected before they develop into cancer, appropriate treatment at this stage can prevent the progression to cancer.
If cell abnormalities progress to cervical cancer, patients may experience the following symptoms:
- Abnormal vaginal bleeding, such as bleeding between menstrual periods or after sexual intercourse
- Postmenopausal vaginal bleeding
- Prolonged or heavy menstrual bleeding
- Foul-smelling vaginal discharge
- Pain during sexual intercourse
- Pelvic pain
As cervical cancer progresses to advanced stages, symptoms become more pronounced, including lower abdominal or back pain, difficulty with urination or defecation, blood in urine or stool, kidney obstruction, swelling of the legs, and other symptoms. Unfortunately, when patients notice these symptoms, it may indicate that the disease has reached an advanced stage. Therefore, if you notice any early symptoms of cervical cancer, it is important to seek medical attention promptly to avoid delays in diagnosis and treatment.
1.5 Diagnosis of cervical cancer
If a doctor suspects cervical cancer after a consultation and gynecological examination, they will arrange further diagnostic tests to determine the cause. These may include:
Colposcopy
Colposcopy is a specialized examination using a colposcope, which is equipped with a microscope for the doctor to observe the condition of the cervix and perform a biopsy if necessary. During the examination, the doctor first uses a speculum to open the patient’s vagina and then uses the colposcope to illuminate and magnify the cervix. This allows for a detailed examination of the cervix, and if any lesions are detected, a small tissue sample can be taken for biopsy to establish a diagnosis.
Additionally, if the doctor confirms cervical abnormalities or early-stage cervical cancer, they may perform surgical procedures during the colposcopy to remove the affected tissue for further pathological examination:
Cone Biopsy
The doctor performs a cone-shaped excision of the abnormal tissue from the location of the cervical lesion under general anesthesia. The excised tissue is then sent for pathological analysis.
Loop Electrosurgical Excision Procedure (LEEP) or Loop Diathermy
The doctor uses a heated wire loop to excise the abnormal tissue within the cervix. The procedure can also cauterize any bleeding during the excision. The excised sample is sent for pathological examination.
Pelvic Ultrasound Scan
Pelvic ultrasound scan, also known as ultrasonography examination of the pelvis, is a non-invasive imaging test. The ultrasound device uses sound waves to create images of the uterus and other pelvic organs through the patient’s skin, providing additional clinical information to the doctor.
Computed Tomography (CT) Scan and Magnetic Resonance Imaging (MRI)
CT scan and MRI are more detailed imaging tests. During these examinations, the doctor may administer a contrast agent through intravenous injection to enhance the clarity of the scan images. The data obtained from these scans are reconstructed by a computer to create cross-sectional images of the body, helping the doctor observe the extent of tumor cell involvement and accurately stage the tumor.
1.6 Staging of cervical cancer
After the examinations, the doctor can determine the stage of the cancer based on clinical information. The most commonly used staging system is the AJCC (American Joint Committee on Cancer) staging system:
| Stage 1 | The cancer cells have invaded the underlying tissues but the tumor is still confined to the cervix. |
| Stage 2 | The tumor has extended into nearby tissues of the cervix or the upper part of the vagina. |
| Stage 3 | The tumor has spread to the side of the pelvic wall or has extended into the lower third of the vagina. |
| Stage 4 | The tumor has spread to other major organs of the body, such as the lungs, colon, or bladder. |
1.7 Treatment of cervical cancer
After staging the tumor, the doctor needs to tailor a suitable treatment plan for the patient, taking into consideration factors such as tumor location, size, stage, invasion depth, and the patient’s overall health. Generally, if the tumor is in the early stages and confined to the cervix, the doctor will often recommend surgical removal. Conversely, if the tumor has spread extensively, surgery may not be able to completely remove all cancer cells, and other treatment options like chemotherapy need to be considered.
Surgery
For early-stage cancer, the doctor may perform a surgical procedure using a colposcope. Under general anesthesia, the doctor can perform procedures such as cone biopsy, large loop excision of the transformation zone (LLETZ), or loop diathermy to remove the cancerous cervical tissue for pathological examination.
Hysterectomy
Hysterectomy is typically suitable for stage 1 and some stage 2 cervical cancer patients without evidence of tumor spread. The surgery is performed under general anesthesia, and it involves removing the entire uterus, cervix, upper part of the vagina, and pelvic lymph nodes to ensure complete removal of the cervical tumor.
Radiation Therapy
Radiation therapy, also known as radiotherapy, uses radiation to kill cancer cells and control tumor growth. It is the primary treatment option for some stage 1 and stage 2 patients and can be used in combination with surgery. In cases where surgery is not suitable for patients due to their overall health, radiation therapy can be used as the primary treatment.
Radiation therapy is also suitable for advanced-stage or metastatic cervical cancer to control and shrink tumors. It can be delivered through external beam radiotherapy, where high-energy radiation is directed at the pelvic area, including the uterus, cervix, and surrounding tissues. Alternatively, brachytherapy, a form of internal radiation therapy, involves placing small radioactive sources directly into the vagina and cervix to deliver radiation to the affected areas.
Chemotherapy
Chemotherapy involves the use of anti-cancer drugs administered intravenously to kill cancer cells. It can be used as adjuvant therapy alongside radiation therapy or surgery to reduce the risk of recurrence. Chemotherapy is also an option for advanced-stage or metastatic cervical cancer patients.
1.8 How to prevent cervical cancer?
To prevent cervical cancer, women should not only practice safe and hygienic sexual behaviors to prevent sexually transmitted infections but also undergo regular cervical cancer screening.
During a cervical cytology (Pap smear) test, healthcare professionals use a speculum to gently open the vagina, allowing them to examine the cervix. They then use a small brush or spatula to collect a sample of cervical cells by gently scraping the surface of the cervix. The collected cervical cell sample is examined under a microscope to detect any abnormal changes in the cervical cells.
Currently, international guidelines recommend that women should initially have two cervical cytology tests one year apart, and if the results are normal, they can continue screening every three years. Research shows that this approach can effectively reduce the incidence of cervical cancer by up to 90%. The Hong Kong government currently recommends that all women aged 25 to 64 who have been sexually active should undergo cervical cytology testing.
For women who have not yet been sexually active, receiving the human papillomavirus (HPV) vaccine is a suitable preventive measure against cervical cancer. There are three types of HPV vaccines registered for use in Hong Kong: the 9-valent, 4-valent, and 2-valent vaccines. All of them can prevent about 70% of cervical cancers caused by HPV types 16 and 18. The vaccination schedule typically involves receiving 2 to 3 doses. However, since the vaccines do not protect against all cancer-causing HPV types and cannot eliminate all latent HPV infections in the body, women should still undergo regular cervical cancer screening to minimize the risk of developing the disease.