Will a new test improve survival rates for cervical cancer?
According to a paper which appeared recently in the New England Journal of Medicine a DNAThe building blocks of the genes in almost all living organisms - spelt out in full as deoxyribonucleic acid. test outperformed the Pap smear in reducing deaths from cervicalRelating either to the cervix (the neck of the womb) or to the cervical vertebrae in the neck (cervical spine). cancerAbnormal, uncontrolled cell division resulting in a malignant tumour that may invade surrounding tissues or spread to distant parts of the body.. I asked Adeola Olaitan for her thoughts.
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Countries in the developing world have a disproportionately high incidenceThe number of new episodes of a condition arising in a certain group of people over a specified period of time. of cervical cancer mainly to the lack of effective screeningA way to identify people who may have a certain condition, among a group of people who may or may not seem to. Thus, the efforts of Sankaranarayanan et al. identify a low cost, reproducible and reliable screening method is welcome.
The results are encouraging: In a low-resource setting, a single round of HPVAn abbreviation for human papilloma virus, a sexually transmitted virus that can cause genital warts and may also have a role in the development of various cancers. testing was associated with a significant reduction in the numbers of advanced cervical cancers and deaths from cervical cancer.
It must be recognised however that these results were achieved within a strictly regulated study environment.
Before accepting HPV testing as a solution to screening in the developing world, it is important to determine the efficacy of the test in a real world setting. I foresee a number of obstacles.
1. Infrastructure: countries with no cultureThe growth within a laboratory of microbes, organisms too small to be seen with the naked eye. of cervical screening may encounter difficulty identifying eligible women, inviting them to undergo testing and monitoring response. Screening tests save lives only if a significant proportion of the eligible population is covered. The NHSCSP in this country aims at a minimum 80% coverage.
2. The model tested by S... et al requires a second visit for women with positive results. Several screening studies in the developing world have reported a high loss to follow up rate in similar studies. This raises questions about the ethics of screening if women with a positive result cannot be contacted for treatment.
3. Although VIA performed far worse in this study group than has previously been reported, it remains an attractive option, with it's ability to yield an instant result and allow for immediate diagnostic testing and/or treatment.
4. Cost. The authors identify the high cost of this screening technique. Even if the test is made available at a tiered rate for developing countries, there are still hidden costs for laboratory tests, recall and follow up.
On the positive side, this is a mechanised tests that avoids the limitations of individual variability and human error which have long been the limitations of cytologyThe study of cells, in medicine used to mean examination of cell samples under a microscope..
Thus on the balance, a reduction in death rate from cervical cancer is good news but more information is required before the wholesale introduction of these tests.
