Gynecological Cancer – 1
(All the articles published in past are available at www.shyamhemoncclinic.com/blog/)
Question: Thank you Chiragbhai for explaining about lung cancer in detail. We have covered most common cancers by now, including Head and Neck, Gastrointestinal, Breast, Lung, and Blood cancers. What is the next topic we are going to cover?
Ans: One big area still uncovered is Gynecological cancers. Cancer of cervix is still very common in India. About 120,000 women are diagnosed each year with cervix cancer, and about 67,000 die due to this cancer each year. Other less common ones in this category are mainly cancers of ovary, uterus, vulva.
Cervical cancer is of particular interest for various reasons. Most important risk factor for cervix cancer is HPV (human papilloma virus) infection. Out of many HPV types, 15 are most common as the risk factor. Out of these, type 16 and 18 are responsible for about 70% of cancers. Many women are infected with HPV, but most of them clear the virus. Some have persistent infection, which leads to incorporation of HPV gene E6 and E7 into cervix cells, and inactivation of tumor suppressor genes such as TP 53. This leads to development of cancer over several years.
Fortunately, cancer of cervix develops very slowly. Precancerous changes can be detected several years before cancer formation, by various tests. Most common one used worldwide has been PAP smear. This test can be done during routine gynecological examination, with a small spatula. Fluid is collected from cervix and smeared on a glass slide and examined by a pathologist conversant with cytology reading. This test is extensively performed in developed countries, and has brought down cervix cancer incidence drastically there. Most cancers there are detected in this preinvasive stage, known as CIN (cervical intraepithelial neoplasia) 1, 2, or 3. PAP smear is the best cancer screening test available today, much better than all other tests like mammogram, PSA etc. In USA, it is performed as part of routine health check up by not just gynecologist, but also by physician or general practitioner.
PAP test should start at age 21 and continue every 3 years till age 65 in general.
Knowledge of HPV subtypes has led to further improvements in testing by use of liquid based cytology etc. These tests help in refining cancer risk better, hence better tailoring of test frequency and next level tests.
Another improvisation for developing countries like India, is use of Acetic acid for testing, known as VIA (visual inspection using acetic acid). This test marks affected area of CIN as white, allowing treatment in the first visit itself, rather than calling women for a follow up visit. Follow up visits are difficult in developing countries, as there is poor compliance for the same. Many of these tests are done as part of camps by hospital, NGO etc.
In general, women with CIN 2 or 3 stage are considered for next level test, known as colposcopy. This is essentially an outpatient procedure, where affected part of the cervix is removed.
Que: Amazing! So cervix cancer is actually a result of infection, and early diagnosis is so easy. Most other cancer screening tests detect cancer stage, whereas PAP smear actually detects precancerous changes, resulting in much better outcome. Since this is an infection, is there a way to prevent it, and are there any other risk factors for cervix cancer?
Ans: Risk factors for cervix cancer include HPV infection, smoking, immunocompromised state (such as HIV, post transplant). Behavioral risk factors associated with higher chance of obtaining HPV infection include: early age of onset of sexual activity, multiple sexual partners or a partner who has multiple partners, history of sexually transmitted disease.
And yes, since this is an infection, fortunately now there is a vaccine against HPV. It is highly effective, with over 90% reduction in risk of CIN 2 or higher stage, if given before HPV infection. At later stage i.e. after infection, efficacy drops by about half. It is to be given at young age, preferably before onset of sexual activity. Various guidelines recommend different ages, between 9 to 13, or up to even 21 in some cases. Standard recommendation has been 3 doses, but very recently US guidelines have recommended that 2 doses are sufficient for age below 15. And 3 doses after age 15. This new recommendation of only 2 doses for age below 15 is important for India, considering the current higher cost.
Que: Thank you for this extremely interesting and clinically useful information. How do we make an early diagnosis? Can we use PAP smear to make diagnosis?
Ans: Most women present with abnormal bleeding i.e. after menopause, or between cycle, or after intercourse. PAP smear can be normal in 50% cases of cancer, hence if there are symptoms, one should not rely only on PAP smear. In advance cases, there may be foul smelling discharge, pelvic pain as well.
December 11th 2016.
Dr. Chirag A. Shah; M.D. Oncology/Hematology (USA), 079 26754001. Diplomate American Board of Oncology and Hematology. Ahmedabad. firstname.lastname@example.org Shyam Hem-Onc Clinic. 402 Galaxy, Near Shivranjani, Opp Jhansi ki Rani BRTS, Ahmedabad. www.shyamhemoncclinic.com