HPV: The leading cause of cervical cancer

An estimated 75% of sexually active Canadians of both sexes will be infected with HPV during their lifetimes.[1] This is not surprising, as the virus is extremely contagious. Skin-to-skin contact in the genital area, even without penetration, is often enough to spread it.

In addition, there are more than 200 types of HPV, around 40 of which can infect the genital tract. During their lifetime, an individual can therefore be infected by more than one type of HPV, or even several times by the same type. Fortunately, the vast majority of these infections disappear on their own, very often without the infected individuals knowing.

However, some types of HPV can lead to the appearance of genital warts (condylomas), while around 15 others can cause cancer. These so-called high-risk types of HPV can cause cancer of the penis in men, of the throat, mouth or anus in both sexes and, in women, of the vulva, vagina and, more frequently, the cervix.[2]

In 2019, an estimated 1,350 Canadian women were diagnosed with cervical cancer and 410 died from the disease.[3] Why does HPV, which disappears on its own in the majority of infected individuals, turn into an agent of cancer in some women?

Predisposing conditions

When a high-risk type of HPV infects a cell in the cervix, it alters the way the cell functions, causing it to reproduce new HPV particles. If the virus is present for long enough, proteins involved in this reprogramming will trigger uncontrolled multiplication of infected cells. Normally, our immune system should be able to recognize these abnormal cells and neutralize them before they invade the organs. But certain situations, or combinations of situations, allow them to escape our defence mechanisms.[4]

Risk factors for cervical cancer

• Presence of high-risk HPV (HPV 16, 18 or 31)
• Weakening of the immune system (medication, AIDS)
• Smoking (associated with greater persistence of the virus)
• Early sexual relations and multiple sexual partners (increased exposure to multiple types of HPV)
• Concomitant STBBI (double the risk if co-infected with chlamydia)

The time factor

As the number of abnormal cells increases, a lesion forms on the cervix. This lesion, still benign, is made up of what are known as precancerous cells. Eventually it will be detectable during an examination of the cervix, and analysis of the cells under the microscope (gynaecological cytology or Pap test) will determine its nature. If this lesion is not detected or treated, it will take many years – 10 to 20 or more – before it becomes cancerous and invades the surrounding tissues.

The problem is that there are generally few symptoms in the early stages of cervical cancer, and the cancer’s progress often goes unnoticed. The most typical symptom is unusual vaginal bleeding after intercourse, between periods or after menopause. There may be other causes for this bleeding, and it is not automatically linked to cancer. At the very least, you should talk to your doctor about this bleeding. Other symptoms of a cancerous lesion range from pain and discomfort during intercourse to a foul-smelling vaginal discharge.[5]

Effective treatments Most women who have cervical cancer undergo surgery, most often a radical hysterectomy, which involves removal of the cervix, uterus, surrounding tissues and upper vagina. Depending on the case, this operation may be combined with radiotherapy and chemotherapy. Thanks to these treatments, the five-year survival rate for everyone diagnosed is 74%,[10] rising to more than 92% for cases detected early (44% of cases).[11]

As with other cancers, there are regular proposals to improve cervical cancer treatment. A recent study, led by the Canadian Cancer Trials Group in collaboration with the Gynecologic Cancer InterGroup, showed that radical hysterectomy could in many cases be beneficially replaced by simple hysterectomy (uterus and cervix), which involves far fewer side-effects and has less impact on quality of life and sexual health.[11]

However, these treatments could one day become obsolete. Thanks to vaccination against HPV, along with screening and improved follow-up of abnormal results, it may be possible to eradicate cervical cancer in Canada by 2040.[12]

Take charge of your health with periodic cervical cancer screening

Book a screening, or contact Biron Groupe Santé customer service at 1 833 251-6006.