How to screen gynecological cancer?
Article: Prof Abraham Peedicayil is a Senior Consultant in Gynecological Oncology, and served at SQCCCRC for two years. Dr Ikram Burney is a Senior Consultant in Medical Oncology and the lead for the Gynecological Oncology Program at the SQCCCRC.
Management of gynecological cancers across the continuum of care – Part 2
This is the second of a series of several articles intended to increase awareness about cancers of the female genital tract. Management of cancer can be seen across the continuum of care, from prevention, early detection, diagnosis, treatment and symptom management through survivorship.
Screening for Gynecological Cancers
The word ‘Screening’ refers to looking for cancer or the precancerous condition before the onset of symptoms. Through screening, cancer can be detected in the pre-invasive stage or in an early stage of cancer, when treatment is easier, and chances of cure are very high.
Screening for early detection of a disease should be considered when the disease is common, could have serious consequences, has a long latent period, the proposed test is simple and non-invasive, the disease can be detected early, and the treatment at an early stage of disease results in longer survival.
Screening should be done periodically during the time when the risk of getting the cancer is high. Screening for early detection can be:
- Primary screening: Organized population-based screening with an intent to reduce cancer incidence and mortality in the community, country, or the society.
- Secondary Screening: For high-risk population (Risk is based on genetic and environmental risk factors)
- Opportunistic screening: Offered to patients attending the hospital for other reasons
At the SQCCCRC, we in the Women Health Program offer screening for breast and cervical cancer to all patients attending the OPD. In addition, patients are referred for screening of cancer of the cervix and the uterus by other clinical programs at the cancer center. We can also offer screening for high-risk individuals.
Cancer of the uterine cervix is one of the most common cancers worldwide, and the most common cancer among women in some parts of the world. Incidence in Oman has been described previously, in “Management of gynecological Cancers across the continuum of care – Part 1”
The cancer is caused by Human Papilloma Virus (HPV), which is transmitted during sexual activity. In most instances, the body’s immune system gets rid of the virus, but in some cases, the virus persists, and can lead to a stage of ‘pre-cancer’. Pre-cancer (Cervical Intra-epithelial Neoplasia or CIN) usually does not produce any symptoms and may take 5 to 10 years to progress to an invasive cancer. This long latent period provides a window of opportunity for screening.
CIN can be detected by various screening tests such as visual inspection with acetic acid or Lugol’s iodine, Pap smear cytology, and detection of the DNA of HPV. HPV DNA is considered the ‘gold standard’ test for screening and is available at the SQCCCRC. Individuals with an abnormal screening test are seen in the OPD (Colposcopy clinic) where the cervix is visualized with good lighting and magnification. Biopsies of suspicious areas are taken to confirm or refute the diagnosis.
It is recommended that sexually active or married women, 25 to 65 years of age, should have a Pap smear every 3 years or an HPV test every 5 years. Confirmed precancer can be easily treated by ablative methods such as cryotherapy or thermocoagulation. Large lesions will need excision by a loop electrode or a knife conization in the operating room. Micro-invasive or stage IA cancer can be treated by conization, if fertility is desired, or by simple hysterectomy if fertility preservation is not required.
Endometrial carcinoma is the most common gynecological cancer in the developed countries. The lifetime risk of endometrial cancer is 2.4%. Most women present with abnormal perimenopausal or postmenopausal bleeding in early stages of the disease.
At present, screening is not recommended for the general population, since there is no good screening test. However, women with a family history of uterine, colon, breast and other cancers may have an inherited cancer predisposition syndrome called the Lynch syndrome or Hereditary Non-Polyposis Cancer Coli syndrome (HNPCC). Almost 5-6% of the cases of Endometrial cancer are due to the syndrome. People who harbor mutations in genes leading to the inherited predisposition have a 50-60% risk of getting endometrial cancer during their lifetime, and they are advised to undergo annual surveillance from the age of 30 years, until the time of hysterectomy which should be done by age 40, or when further fertility is not desired. These women should also be screened for colorectal cancer. Furthermore, patients receiving Tamoxifen or having received radiotherapy to the pelvic region should undergo transvaginal ultrasound scan for endometrial thickness and endometrial sampling if there is any abnormal bleeding.
The lifetime risk of ovarian cancer is 1.4%. Screening of women with average risk in general population is not recommended, since there is no good screening test. However, individuals who develop epithelial ovarian cancer at a very young age, those who have a history of ovarian or breast cancer or both in the family, or even prostate cancer amongst men in family, may have mutations in BRCA1 or the BRCA2 gene. The family member affected by the cancer should be assessed for a genetic mutation, and if a particular mutation is detected, then the same mutation should be assessed in the unaffected first-degree relatives. If a mutation is detected in BRCA1 gene, the lifetime risk of getting ovarian cancer is 45%, and removal of both ovaries (risk-reducing salpingo-oophorectomy) is recommended as soon as fertility is no longer desired. Additionally, since the risk of breast cancer is high (65%), a very close observation is recommended, and risk reducing bilateral mastectomy should be considered. If a mutation is detected in BRCA2 gene, the lifetime risk of getting ovarian cancer is 12%, and removal of both ovaries (risk-reducing salpingo-oophorectomy) should be discussed. Preventive measures for breast cancer are the same as with BRCA1 mutation.
Screening for vulval and vaginal cancers, germ cell cancer of the ovary, and trophoblastic tumours is not routinely recommended. These cancers are relatively uncommon, and there are no good screening tests. However, patients who undergo routine surveillance of cancer of the uterine cervix, may be detected to have vulvar or vaginal abnormalities and could be screened with cytology and HPV testing. After evacuation of a molar pregnancy, women need to be under close surveillance for at least 6 months.