Multidisciplinary Program Needed to Reduce CC NumbersThu, 09/07/2017 - 13:45
One in 10 cancer-related deaths in Mexican women is caused by cervical cancer (CC), which kills 11 women every day, according to the Mexican Ministry of Health. While in 2006 breast cancer replaced CC as the first cause of death by cancer in Mexican women, according to INEGI, CC killed 4,009 women in 2015. The highest mortality rates belong to the states of Morelos, Oaxaca and Chiapas, validating the fact that CC is an inequality indicator since its mortality tends to concentrate in the least economically favored regions throughout our country.
The primary cause of CC is chronic infection with a highrisk type (16 and 18) of human papillomavirus (HPV), the most common infection acquired during sexual relations. In most women, these infections resolve spontaneously, but a minority persist and may progress to CC 10 to 20 years later. This gap offers an opportunity to detect and treat precursor lesions. The Pap smear is a well-established method for examining the cells collected from the cervix to determine whether they show signs of these lesions. It is a free and essential screening test that must be done annually. It can be done every two or three years if the patient has three consecutive normal tests.
The evolution of CC has been widely studied and its precursor lesions identified. In 1988 the Bethesda system (TBS) for reporting cervical cytologic diagnosis was first introduced and revised in 1991, 2001 and 2014. Its aim is to develop a uniform terminology for cervical cytology interpretation and upright communication between pathologists and clinicians. TBS reports have three basic components: a descriptive interpretation, a statement of specimen adequacy and, optionally, a general categorization of the interpretation. TBS defines the squamous intraepithelial lesions, as well as all the HPV associated noninvasive squamous cell abnormalities, and divides them between low-grade squamous intraepithelial lesions (LSIL) and highgrade squamous intraepithelial lesions (HSIL). Specimens with subtle changes can be classified as atypical squamous cells of undetermined significance (ASC-US). This division has a better inter-observer reproducibility than other reporting systems.
The features of LSIL include nuclear enlargement with hyperchromasia or pyknosis and irregular nuclear contours along with a perinuclear cavity and peripheral thickening of the cytoplasm. Features that favor HSIL include increased numbers of abnormal cells, higher nucleus to cytoplasmic ratios, greater irregularities in the outline of the nuclear envelope and nuclear chromatin distribution. The appearance of the cytoplasm can help to distinguish LSIL from HSIL in borderline cases. LSIL involve mature, intermediate or superficial cytoplasm with polygonal borders, while cells of HSIL have an immature cytoplasm, either delicate or dense with rounded cell borders.
Based on the natural history of HPV infections, the majority of LSIL regresses within an average of two years. However, when LSIL or HSIL is detected by a Pap smear, a colposcopy is recommended within six weeks; if HSIL is detected, a biopsy should be performed and the patient must be treated with cryotherapy or loop electrosurgical excision procedure (LEEP). If HSIL is not detected, the cytology must be repeated at six to 12 months. The treatment of CC includes surgery, chemotherapy and radiotherapy.
A national program of CC screening has been in operation since the 1970s, and ENSANUT reports 45.5 percent of Mexican women of reproductive age had a Pap smear in 2012, with increasing numbers and a plan to reach at least 70 percent by 2018. Although screening with cervical cytology has diminished CC in our country we still have the highest mortality rates among OECD members. The Ministry of Health has almost 2,000 employees working in the national screening program, including colposcopists, pathologists and cytotechnologists, but they are not equally distributed or skilled, which hinders some women’s access to efficient screening. Our health system must focus on risk factors and low participation in screening programs that dismiss many women from timely detection of precursor lesions. Only a multidisciplinary program established by determined policymakers, managers and professionals in the health sector will meet the extent and quality indicators needed for a real solution for the current numbers of CC in Mexico.