Vaginal Cancer

Vaginal cancer is an exceptionally rare form of cancer, originating in the tissue of the vagina. It is classified into two main categories: primary and secondary vaginal cancer. Primary vaginal cancer originates from the vaginal tissue, with squamous cell carcinoma being the most common type. Other types include adenocarcinoma, sarcoma, and melanoma. Secondary vaginal cancer, which is more common, involves metastasis from cancers originating in other parts of the body.

Signs and Symptoms

Vaginal cancer often does not cause signs or symptoms in its early stages. When symptoms do occur, they may include abnormal vaginal bleeding, heavy menstrual flow, bleeding after menopause, intermenstrual bleeding, blood in stool or urine, frequent or urgent urination, constipation, dyspareunia, and palpable lumps or growths in the vagina. Enlarged pelvic lymph nodes may also be detected upon palpation.

Risk Factors

Several risk factors are associated with vaginal cancer, including:

• Prenatal exposure to diethylstilbestrol (DES)
• Infection with human papillomavirus (HPV) type 16
• Infection with human immunodeficiency virus (HIV) type 1
• Previous history of cervical cancer
• Smoking
• Chronic vulvar itching or burning

Types

There are several types of vaginal cancer:

• Squamous-cell carcinoma: Arises from the squamous cells lining the vagina, most common in women aged 60 or older.
• Adenocarcinoma: Originates from glandular cells in the vaginal lining, more likely to metastasize to the lungs and lymph nodes.
• Clear cell adenocarcinoma: Linked to DES exposure in utero, primarily in women born between 1938 and 1973.
• Vaginal germ cell tumours: Rare, found primarily in infants and children.
• Sarcoma botryoides: A type of rhabdomyosarcoma, also found in infants and children.
• Vaginal melanoma: A melanoma occurring in the vagina.

Diagnosis and Screening

Routine screening for vaginal cancer is not recommended for asymptomatic women due to the rarity of the disease and the ineffectiveness of such measures in improving survival rates. Several diagnostic tests are used when symptoms are present, including physical exams, pelvic exams, biopsies, and colposcopies. MRI is useful for visualising the extent of the cancer. It is essential to rule out other sources of cancer, such as the urethra or cervix, before confirming a diagnosis of vaginal cancer. Cervical pap smears do not detect vaginal cancer.

Staging

The International Federation of Gynaecology and Obstetrics (FIGO) uses the Tumour, Node, Metastasis (TNM) system to stage vaginal cancer:

• Stage I: Tumour confined to the vagina
• Stage II: Tumour invading nearby tissues but not the pelvic wall
• Stage III: Tumour invading the pelvic sidewall or causing hydronephrosis by obstructing the ureter
• Stage IV: Tumour invading nearby pelvic organs or spreading beyond the pelvis

Management

Historically, external-beam radiation therapy (EBRT) has been the most common treatment for vaginal cancer. Surgery also plays a role, especially in early-stage cancer. Advanced stages have lower survival rates, but newer treatments, including concurrent carboplatin plus paclitaxel, EBRT, and high-dose-rate interstitial brachytherapy (HDR-ISBT), show promise. Radiation therapy is often used when surgical removal is not feasible or poses a high risk of damaging surrounding organs. Tumours smaller than 4 cm in diameter treated with radiation therapy have a five-year survival rate exceeding 80%. Treatment plans are highly individualised due to the rarity of the disease.

Epidemiology

Vaginal cancer accounts for only 2% of all gynaecological cancers and less than 0.5% of all cancers in women. In 2017, there were an estimated 4,810 new cases and 1,240 deaths in the United States. In the UK, 254 cases were identified in 2014, with 110 deaths. About 53% of vaginal cancer cases are related to HPV infection.

Research

Due to the rarity of vaginal cancer, there have been few phase three clinical trials. An ongoing phase three trial is studying the efficacy of the drug triapine, and several phase one and two trials are investigating new gynaecological cancer treatment regimens that include vaginal cancer.

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Self-assessment MCQs (single best answer)

What is the most common type of primary vaginal cancer?

Which of the following is NOT a symptom of vaginal cancer?

Which virus is associated with an increased risk of vaginal cancer?

Which type of vaginal cancer is linked to prenatal exposure to diethylstilbestrol (DES)?

What is the main method used to confirm a diagnosis of vaginal cancer?

Which stage of vaginal cancer is defined by the tumour being confined to the vagina?

What is the five-year survival rate for tumours smaller than 4 cm treated with radiation therapy?

Which treatment is often used when surgical removal of vaginal cancer is not feasible?

What is the most common age group for squamous-cell carcinoma of the vagina?

What percentage of vaginal cancer cases are related to HPV infection?