Causes of Cervical Cancer explained by Dr. Saurabh Mohite

Human Papilloma Virus (HPV) is found in over 99 per cent of cervical cancers. Although infection with a high risk type of Human Papilloma Virus (HPV) is necessary for cervical cancer to develop, not every woman who is infected with it will go on to develop the disease. What makes any individual woman develop cervical cancer is not known, although we know that certain factors increase the risk of this happening. There are many types of HPV and only some cause cancer. The HPV vaccine protects against Human Papilloma Virus associated with the development of cervical cancer. The vaccine currently in use covers the two most important types which cause 70 to 75 per cent of cervical cancers

In this Health Blog Consultant Surgical Oncologist, Dr Saurabh Mohite explains more about Risk Factors of Cervical Cancer

• Some types of Human Papilloma Virus, in particular HPV 16 and HPV 18, the types included in the vaccine, are found in over 99 per cent of cervical cancers. These are known as ‘high risk’ types. Some other types (eg HPV 6 and HPV 11) can cause genital warts. Those which cause genital warts do not place a woman at increased risk of developing cervical cancer. Some types of HPV appear to be harmless
• The majority of sexually active women will come into contact with high risk HPV types at some time in their life. In most women (90 per cent), their body’s own immune system will get rid of the infection without them ever knowing it was there. Only a minority of those who are positive for high risk HPV types will develop cervical abnormalities (CIN) which could develop into cervical cancer if left untreated
• Women with many sexual partners, or whose partners have had many partners, are more at risk of developing cervical cancer. This is because their behaviour is more likely to expose them to HPV. However, a woman with only one partner could contract HPV if that partner has previously been in contact with the virus
• Women who are immunosuppressed (for example, those who are taking immunosuppressive drugs after an organ transplant, or women who are HIV positive) may be at increased risk of developing cervical cancer
• Long term use of oral contraceptives increases the risk of developing cervical cancer
• Women who smoke are about twice as likely to develop cervical cancer as nonsmokers. This may be because smoking is associated with high risk health behaviours or because it suppresses the immune system allowing the persistence of high risk HPV infection. Stopping smoking appears to help clinical abnormalities to return to normal
• Using a condom offers only very limited protection from transmission of HPV
• Women with a late first pregnancy have a lower risk of developing cervical cancer than those with an early pregnancy. The risk rises with the number of pregnancies 

What about women who are not sexually active?

If a woman has never been sexually active, then research evidence shows that her chance of developing cervical cancer is very low indeed. In these circumstances, a woman may refuse cervical screening. If a woman is not currently sexually active but has had partners in the past, we would recommend that she continues screening.

The NHS Data

In the first ten years of the organized screening program implemented by the NHS in UK, cervical cancer incidence fell by 42 per cent. Cervical cancer mortality rates in 2007 (2.4 per 100,000 females) were nearly 70 per cent lower than they were 30 years earlier (7.5 per 100,000 females in 1977). The latest relative survival figures for England show that 63 per cent of women diagnosed with cervical cancer between 2000 and 2001 were alive five years later. These statistics validate the efficacy of screening programs in improving cure rates in cancer through early diagnosis and treatment.