lesions of the cervix.
Diethylstilbestrol (DES)
DES is a hormonal drug. Women with the use DES
developed clear-cell adenocarcinoma of the vagina or cervix. They were found to be more prone than expected for cervical carcinoma. These carcinoma is rarely found in women unexposed to DES. There is about 1 case of vaginal or cervical clear-cell
adenocarcinoma in every 1,000 women whose mothers took DES during pregnancy. DES-related clear cell adenocarcinoma occurs more commonly in the vagina than the cervix.
DES-related cancer. Doctors do not know exactly how long these women will remain at
risk.
Family history of cervical cancer
The risk of cervical carcinoma increases with a positive family history of cervical carcinoma in first degree relatives.
Studies have identified a number of risk factors that contribute to the development of cervical cancer precursors and cervical cancer. These factors include infection with certain oncogenic types of human papilloma viruses (HPV), sexual intercourse at an early age, multiple sexual partners, multiparity, low socioeconomic status, long-term use of oral contraceptive, tobacco smoking, infection with Chlamydia trachomatis, micronutrient deficiency. (IARC, 1995; Bosch etal., 1995; Schiffmanet al., 1996; Walboomerset al., 1999; Franco et al., 1999; Ferenczy& Franco, 2002). HPV types 16, 18, 31, 33, 35, 39, 45, 51, 52, 56, 58,59 and 68 are strongly associated with CIN and invasive cancer (IARC, 1995; Walboomerset al.,1999).
2.6.1 PAP SMEAR
First suggested in 1928 by Dr George Papanicolaou, with findings published in 1941 (Papanicolaou 1997), the Pap smear revolutionalized cervical cancer prevention. Taking advantage of the long period between CIN and invasive cancer and the ease of treatment of precancerous lesions, programs based on cytological screening have had a great impact on the reduction of cervical cancer incidence in mostly developed countries which can afford them. An example is the USA where in the past 60 years, the incidence of cervical cancer has been reduced by 75%, from 32.6 to 8.7 per 100,000 and mortality rates from cervical cancer decreased by 70%, from 9.3 to 2.5 per 100,000 (CDC 2005). Similar and sometimes better results were reported in Europe, especially the Nordic countries (Gustafsson 1997; Anttila 1999). Similar programs have proven too expensive to organize in most low income countries, and alternative feasible methods using visual screening have been suggested (Bradley 2005).
VIA and VILI
Visual inspection with acetic acid (VIA) involves naked-eye inspection of the cervix under bright light conditions at least 1 minute after the application of 3-5% diluted acetic acid (Blumenthal 2005). The test can be carried out by nurses or midwives (Megevand 1993; Sankaranarayanan 1998; University of Zimbabwe/ JHPIEGO project 1999).
A positive result is based on the appearance of well-defined, acetowhite areas in the transformation zone (Blumenthal 2005). This is the region on the cervix that undergoes metaplastic change from columnar epithelium to squamous epithelium. Reported sensitivity of VIA ranges from 52% to 79% and specificity from 49% to 88%, which are similar to those for cytology (Arbyn 2008). However, VIA is inefficient in detecting lesions located in the cervical canal of the uterus (Arbyn 2008).
Visual inspection with Lugol’s iodine (VILI) uses Lugol’s iodine solution applied to the cervix. It stains glycogen stored in cervical epithelial cells. Neoplastic and immature squamous metaplastic epithelium have less glycogen than the normal mature squamous epithelium and so do not turn mahogany brown. Instead they appear as mustard yellow changes, easily recognizable as the acetowhite changes associated with VIA. Sensitivity has been reported to vary from 78% to 98% and specificity from 73% to 91% (Sankaranarayanan 1998). Both VIA and VILI have an added advantage of giving immediate results (Arbyn 2008).
These two methods of visual inspection have been shown to be feasible as a primary means of screening for cervical cancer in low income settings and can be used by well trained nurses.
Because of organizational constraints and reported high rates of loss to follow up, strategies aiming at screening and treatment in the same visit (‘see and treat’) have been proposed. Effectiveness and acceptability have been evaluated in several studies and found to be good (Tsu 2005; Sankaranarayanan 2007; Luciani 2008; Kitpeerakoo 2009). Treatment of precancerous lesions is by either ablative methods, the most common being cryotherapy, or excisional methods, such as cone biopsy and loop electrosurgical excision procedure (LEEP). Unlike LEEP, cryotherapy does not avail a biopsy sample, and thus it is not possible to know if the whole lesion has been destroyed. Cryotherapy is easier to use and can be performed by nurses, making it
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more applicable in low income settings (Sankaranarayan 2007). However, it may not be enough to treat all lesions detected, for example when the entire squamocolumnar junction cannot be visualized, when the lesion is too large for the cryotherapy probe to cover in one application, if lesion extends into the endocervical canal and when there is severe cervical atrophy (Gage 2009).
One disadvantage of ‘see and treat’ screening strategy is overtreatment which has been reported to range from 1.2 to 83.3% (Cárdenas-Turanzas 2005). This is likely to be worse in see and treat strategies without a colposcopy before treatment. Colposcopy has been evaluated and could be an added asset in improving the effectiveness of ‘see and treat’ programs (Mitchell 1998; Benedet 2004). There is evidence that nurses can be trained effectively as colposcopists (Morris 1998; Todd 2002).