Estimate the impact of PSI interventions in selected countries, compare and download results, and explore information about the models used to estimate impact by clicking on the intervention name.
Updated March 29, 2017
Cervical cancer screening of sexually active or formerly sexually active women ascertains risk or presence of cervical cancer and gives women the opportunity to seek preventative therapy or treatment. PSI supports screening based on examination of the surface of the cervix by visual inspection after applying acetic acid (VIA) or Lugol’s iodine (VILI) and cytological examination of cells that have been gently scraped from the cervix using the Pap smear technique. Following detection of precancerous lesions, some PSI clinics or franchises are able to provide cryotherapy – applying a highly cooled metal disc to the cervix to freeze precancerous areas – on site, while others refer to partner clinics or hospitals for preventative therapy. PSI refers all patients who have active cancer for advanced treatment.
For more information about how PSI is increasing access to cervical cancer screening and treatment to improve health and save lives, visit our website at:
When a client is referred by PSI to a non-PSI supported service provider, such as the public sector, PSI attributes 50% of the impact of that service to the referral issued by PSI. This impact is only attributed to PSI when the referral is confirmed with appropriate documentation. Referral to treatment is often needed when PSI screens a patient but cannot provide treatment outside of the public sector.
The health impact in PSI DALYs averted model is based on successful treatment with preventative therapy. To estimate this impact, the model uses data on age-specific incidence and mortality of cervical cancer, precancerous lesion progression, sensitivity and specificity of the screening method, and treatment efficacy of cryotherapy (or conization).
For women in three age groups (15-39, 40-44, and 45-49), the model runs a scenario to estimate 1) how likely it is that a woman with a precancerous lesion will test positive and be treated by PSI or other health care providers, 2) how likely it is that she will develop invasive cancer if left untreated, and 3) how likely it is that she will be prevented from developing cancer if treated. This results in the cases averted per treatment or per screening and referral (cases averted coefficient).
Next, deaths averted per treatment (or per screening and referral) are estimated by multiplying the cases averted coefficient by the case fatality rate. The cases averted and deaths averted coefficients are then translated into an equivalent figure measured in DALYs averted per treatment (or per screening and referral) using data from the www.healthdata.org/gbd study.
The health impact of PSI’s screening and treatment programs depends on both the outcome of the screening and whether or not the facility has the capacity to treat any positive (abnormal) findings or must refer the client to treatment.
To accommodate the various outcomes that may result from cervical cancer screening, the model produces a set of ten DALYs averted coefficients for each country. Use only the coefficients that are applicable to the program in your country.
Estimates of DALYs averted, deaths averted, CYPs provided, and unintended pregnancies averted represent the projected health impact of the intervention. It is
projected because it has not been directly measured.
If 10,000 individuals receive cryotherapy following a VIA screening in Kenya in 2015, an estimated 2,127 DALYs would be averted.