Cervical cancer and It’s prevalence in Canada

Cervical cancer also called cancer of the uterine cervix is the malignant neoplasm originating in the cells of the cervix. Cancer of the cervix uteri is the fourth common cancer among women worldwide with an estimated 604,127 new cases and 341,831 deaths in 2020.

Cervix is a part of the female reproductive system that connects the upper body of the uterus to the vagina. It is about 3 to 4 cm long and made up mostly of connective tissue and muscle. 

Cervix is divided into two main parts. The endocervix, the upper part which is close to the uterus, is covered by glandular cells, and the ectocervix, the lower part which is close to the vagina, is covered by squamous cells. The transformation zone refers to the place where these two regions of the cervix meet. Precancerous changes of the cervix and most cervical cancers start in the transformation zone.

The precancerous condition can be caused by changes in the cells of the cervix. If these cells are not treated for a long time, there is the chance that they become cancerous cells. The most common precancerous condition of the cervix is called squamous intraepithelial lesion (SIL), cervical intraepithelial neoplasia (CIN), and cervical dysplasia.

There are several types of cervical cancer, classified based on where they develop in the cervix. Cancer that develops in the ectocervix is called squamous cell carcinoma, and around 80-90% of cervical cancer cases are of this type. Cancer that develops in the endocervix is called adenocarcinoma. In addition, a small percentage of cervical cancer cases are mixed versions of the above two and are called adenosquamous carcinomas or mixed carcinomas. 

Figure 1 (a) Section through the cervix showing malignant growth (b) The zone of transformation marks the site of initiation of  
               malignancy in most cases.

Cervical cancer prevalence in Canada:

In 2020, about 1422 Canadian women diagnosed with cervical cancer and an estimated 637 died from it. It is the third most gynecologic cancer in Canada after corpus uteri and ovary cancer. Cervical cancer is found among female of 15-65+ age group. The highest numbers of cervical cancer cases are found among 40-64 age groups of female.

Figure 2: Incidence and Mortality of gynecologic cancers among women. 2020. Source: GLOBOCAN
Figure 3: Age Specific cervical cancer incidence in Canada. Source: GLOBOCAN

The highest number of cervical cancer cases and deaths were projected in Ontario province following by Quebec, British Columbia and Alberta in 2020. The lowest cervical cancer cases and deaths were projected in Prince Edward Island among all provinces.

  Figure 4: Projected numbers of cervical cancer diagnosis and mortality in Canada. Source: Canadian Cancer Society (2020).

 In Canada, the 5-year net survival for cervical cancer is 72%. This means that about 72% of women diagnosed with cervical cancer will survive for at least 5 years. Cervical cancer incidences can be declined by routine immunization and screenings in Canada.

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