Screening

Women

Breast Cancer

Breast cancer remains the most common cancer in women. Though a higher incidence in well-resourced countries exists, it is become a more significant issue in low-resource countries as well, where diagnosis tends to be later, disease more aggressive, and prognosis poorer (Formenti, Arslan, and Love, 2011).

Breast self-exam is important in low-resource settings. Women should be taught to assess for:

• a palpable lump
• nipple discharge
• skin changes, including redness, peau d’orange
• nipple excoriation or scaling
  

Consider and gently address the mis-information or fears the woman might have.

Image: breast self-exam, used with permission

Clinical breast exam (main article) should be taught to a satisfactory level to the appropriate health care provider. Primary care physicians and non-physician clinicians should be competent in this skill, and there are various efforts to train nurses, midwives and community workers in CBE as well.

Cervical Cancer

Cervical cancer is the second most common cancer among women in developing countries (Ferlay et al., 2012).

While Papanicolau (Pap)-smear testing has been the most effective screening tool in high-income countries, it is not feasible in developing countries due to logistical and implementation challenges. Particularly, the procedure is costly and requires highly trained professionals. Additionally, even in optimal conditions, the readings produced are of low sensitivity. Another well-used screening tool is liquid-based cytology (LBC). LBC is the use of a fluid medium to preserve the collected cervical cells which is then processed to provide a layer of cervical cells without debris on a glass slide. Although it is thought to perform equally well as Pap-smears, it faces similar challenges of implementation (Shastri and Shastri, 2014; International Agency for Research on Cancer).  

As such, two new main screening strategies have emerged as options for resource-constrained areas.

Visual Inspection with acetic acid (VIA)

VIA involves applying 5% acetic acid (vinegar) to the cervix and detecting, with the naked eye, dysplastic cervical epithelium that turns white. Treatment can then follow immediately by the application of liquid nitrogen or carbon nitrogen to the area (Mukakalisa et al., 2014).

Advantages of VIA include: it’s simple and immediate result; does not require elaborate resources; can be performed by nurses and midwives with short training; is accepted by health care workers and women; is inexpensive, at less than $3 USD. The only major weakness is its level of sensitivity. Often times it may cause false positives, but it is at least similar or better than Pap (Jeronimo et al., 2014; Mukakalisa, 2014; Shastri and Shastri, 2014).

(Image: Tsu, 2011)

careHPV

The Human papilloma virus (HPV) is a common cause of cervical cancer. As HPV-DNA tests are often not suitable for developing countries because of limitations such as expense and a highly-equipped laboratory, a recent development based on similar techniques has been made with the alternative careHPV (QIAGEN, Gaithersburg, MD) screening tool.

The test is simple, involving a portable compact unit, and allows women to collect cervical and vaginal samples themselves. As the unit does not require advanced facility settings (ie. no temperature, water or electricity is needed), it is a feasible tool to use in low-resource settings. Additionally, a significant advantage of the self-collection component is that it does not require uncomfortable pelvic evaluation, which could otherwise act as a deterrent, and can thereby increase population coverage, particularly in low resource areas (Jeronimo et al., 2014).

Note on the HPV Vaccine: Though the most effective prevention strategy, the vaccines do not treat precancerous conditions. Therefore, screening will still be necessary. Additionally, since the vaccine does not protect against all the oncogenic genotypes of the virus, even amongst vaccinated cohorts screening procedures, as highlighted above, are necessary (Jeronimo, 2014).

Cervical Cancer

Cervical cancer is the second most common cancer among women in developing countries (Ferlay et al., 2012).

While Papanicolau (Pap)-smear testing has been the most effective screening tool in high-income countries, it is not feasible in developing countries due to logistical and implementation challenges. Particularly, the procedure is costly and requires highly trained professionals. Additionally, even in optimal conditions, the readings produced are of low sensitivity. Another well-used screening tool is liquid-based cytology (LBC). LBC is the use of a fluid medium to preserve the collected cervical cells which is then processed to provide a layer of cervical cells without debris on a glass slide. Although it is thought to perform equally well as Pap-smears, it faces similar challenges of implementation (Shastri and Shastri, 2014; International Agency for Research on Cancer).  

As such, two new main screening strategies have emerged as options for resource-constrained areas.

Visual Inspection with acetic acid (VIA)

VIA involves applying 5% acetic acid (vinegar) to the cervix and detecting, with the naked eye, dysplastic cervical epithelium that turns white. Treatment can then follow immediately by the application of liquid nitrogen or carbon nitrogen to the area (Mukakalisa et al., 2014).

Advantages of VIA include: it’s simple and immediate result; does not require elaborate resources; can be performed by nurses and midwives with short training; is accepted by health care workers and women; is inexpensive, at less than $3 USD. The only major weakness is its level of sensitivity. Often times it may cause false positives, but it is at least similar or better than Pap (Jeronimo et al., 2014; Mukakalisa, 2014; Shastri and Shastri, 2014).

careHPV

The Human papilloma virus (HPV) is a common cause of cervical cancer. As HPV-DNA tests are often not suitable for developing countries because of limitations such as expense and a highly-equipped laboratory, a recent development based on similar techniques has been made with the alternative careHPV (QIAGEN, Gaithersburg, MD) screening tool.

The test is simple, involving a portable compact unit, and allows women to collect cervical and vaginal samples themselves. As the unit does not require advanced facility settings (ie. no temperature, water or electricity is needed), it is a feasible tool to use in low-resource settings. Additionally, a significant advantage of the self-collection component is that it does not require uncomfortable pelvic evaluation, which could otherwise act as a deterrent, and can thereby increase population coverage, particularly in low resource areas (Jeronimo et al., 2014).

Note on the HPV Vaccine: Though the most effective prevention strategy, the vaccines do not treat precancerous conditions. Therefore, screening will still be necessary. Additionally, since the vaccine does not protect against all the oncogenic genotypes of the virus, even amongst vaccinated cohorts screening procedures, as highlighted above, are necessary (Jeronimo, 2014).

Colorectal Cancer

Although the incidence rate of colorectal cancer (CRC) is highest in developed countries, there has not been much focus on obtaining epidemiological data for the developing world. Due to the lack of this focus and the lack of awareness of CRC among the population of the developing countries, there may be a high degree of underreporting (Hagger and Boushey, 2009; Ahmed, 2014). Additionally, as incidence is increasing in many economically developing countries, such as the Asian-Pacific regions (Sung et al., 2014), attributed to ageing populations and the shift to a Western lifestyle, implementation of screening programs for CRC is likely to increase (Center et al., 2009).

If early diagnosis occurs (ie. the extent of the tumour does not develop beyond the bowel wall), there is an over 90% chance of five-year survival (Bretthauer, 2011). As such, there should be an increased effort to establish appropriate CRC screening programs via the following three main strategies:

Faecal Occult Blood Test (FOBT)

Most often used is the FOBT, which detects small, hidden traces of blood (occult blood) in a stool sample. There are two main types: guaiac-based tests (gFOBTs) and immunochemical tests (iFOBTs). The gFOBT uses the chemical guaiac to detect heme in stool samples, whereas the iFOBT uses antibodies to detect hemoglobin protein (Colorectal Cancer Association of Canada).

As the gFOBT requires dietary and medication restrictions, it may be inconvenient. Additionally, iFOBTs are reported to have increased sensitivity and specificity, leading to it’s favourable use among clinicians, even though it is more expensive (Rossum et al., 2008; Sung et al., 2014). In general, FOBT is a repetitive procedure requiring annual or biennial screening (Bretthauer, 2011).

Flexible Sigmoidoscopy (FS)

FS involves the insertion of the sigmoidoscope “through the anal verge into the rectum and advanced into the colon up to a depth of approximately 60cm and may reach the splenic flexure” (Adebogun et al., 2014). Additionally, the procedure can be taught to primary care physicians and nurses, therefore increasing the capacity for population-based screening programs (Adebogun et al., 2014).

Furthermore, disposable sheath sigmoidoscopes are available. Though they do not have video instrumentation, it has been demonstrated to increase turnaround time between cases, and can therefore be effective for use in screening rural communities, particularly for outreach initiatives (Adebogun et al., 2014; Bretthauer et al., 2002).

Colonoscopy

Colonoscopy has the highest level of sensitivity and specificity. The procedure requires the administration of sedation and allows the examination of the entire colon, whereas FS does not need sedation and only examines the lower third (Adebogun et al., 2014; John Hopkins Colon Cancer). However, as colonoscopy requires highly skilled personnel and is the most expensive method, it may not be practical to be used as a first-line test in resource-constrained regions (Sung et al., 2014).

As CRC has not yet been identified as prevalent in developing countries and therefore there are no established population-based CRC screening programs, it is important when moving forward with initiatives to consider differing contexts. For example, colonoscopy with following treatment would be cost effective in the African sub-region, but this is not necessarily applicable to all settings (Ginsberg et al., 2012; Ahmed, 2014).