p16INK4A immunohistochemical staining and predictive value for progression of cervical intraepithelial neoplasia grade 1: a prospective study in China.

p16(INK4A) is strongly expressed in tissues diagnosed as cervical intraepithelial neoplasia (CIN) and cancer in women infected with human papillomavirus (HPV), but few prospective studies have evaluated p16(INK4A) as a marker for the risk of low-grade CIN (CIN1) progression. We investigated the prevalence of p16(INK4A) immunostaining by CIN grade and whether overexpression of p16(INK4A) in CIN1 predicts future risk for high-grade CIN in Chinese women. 6,557 Chinese women aged 30-49 years were screened from 2003 to 2005 using cytology and carcinogenic HPV test. Colposcopy was performed on women with any abnormal result. p16(INK4A) Immunostaining was performed on biopsies from all women with CIN1, as well as randomly selected women with normal or CIN grade 2 and worse (CIN2+) biopsies. Women with CIN1 were followed up without treatment. Colposcopy was performed on all untreated women at a 2-year interval. The prevalence of p16(INK4A) staining was 2.7%, 42.7%, 75.5%, 79.6% and 100% among women with normal, CIN1, 2, 3 and cancer biopsies, respectively (p < 0.001). HPV positivity was strongly associated with p16(INK4A) staining [odds ratios (OR) = 12.8; 95% confidence intervals (CI): 5.2-31.6]. p16(INK4A) staining of CIN1 biopsies at baseline was associated with an increased risk of finding high-grade CIN over 2 years of follow-up (OR = 1.43; 95% CI: 0.52-3.91). The two-year cumulative incidence of CIN2+ for p16(INK4A) positive women was higher at 10.71% than for p16(INK4A) negative women at 1.30% (crude RR = 8.25, 95% CI: 1.02-66.62). p16(INK4A) overexpression is strongly associated with grade of CIN and risk of progression to high-grade CIN in women with low-grade lesions.

Prevalence of human papillomavirus and cervical intraepithelial neoplasia in China: a pooled analysis of 17 population-based studies.

High-risk (HR) human papillomavirus (HPV) prevalence has been shown to correlate well with cervical cancer incidence rates. Our study aimed to estimate the prevalence of HR-HPV and cervical intraepithelial neoplasia (CIN) in China and indirectly informs on the cervical cancer burden in the country. A total of 30,207 women from 17 population-based studies throughout China were included. All women received HPV DNA testing (HC2, Qiagen, Gaithersburg, MD), visual inspection with acetic acid and liquid-based cytology. Women positive for any test received colposcopy-directed or four-quadrant biopsies. A total of 29,579 women had HR-HPV testing results, of whom 28,761 had biopsy confirmed (9,019, 31.4%) or assumed (19,742, 68.6%) final diagnosis. Overall crude HR-HPV prevalence was 17.7%. HR-HPV prevalence was similar in rural and urban areas but showed dips in different age groups: at age 25-29 (11.3%) in rural and at age 35-39 (11.3%) in urban women. In rural and urban women, age-standardized CIN2 prevalence was 1.5% [95% confidence interval (CI): 1.4-1.6%] and 0.7% (95% CI: 0.7-0.8%) and CIN3+ prevalence was 1.2% (95% CI: 1.2-1.3%) and 0.6% (95% CI: 0.5-0.7%), respectively. Prevalence of CIN3+ as a percentage of either all women or HR-HPV-positive women steadily increased with age, peaking in 45- to 49-year-old women. High prevalence of HR-HPV and CIN3+ was detected in both rural and urban China. The steady rise of CIN3+ up to the age group of 45-49 is attributable to lack of lesion removal through screening. Our findings document the inadequacy of current screening in China while indirectly raising the possibility that the cervical cancer burden in China is underreported.

Comparison of ThinPrep and SurePath liquid-based cytology and subsequent human papillomavirus DNA testing in China.

BACKGROUND: Liquid-based cytology (LBC) has been compared with conventional cytology in numerous studies. In the current study of 2 LBC systems, the accuracy, rates of unsatisfactory cytology, and sufficiency of residual LBC specimens for Hybrid Capture 2 (HC2) HPV DNA testing were compared. METHODS: Eligible women ages 30 to 49 years were recruited for this cross-sectional population-based study in rural China. Women were assessed by visual inspection with acetic acid (VIA), LBC, and high-risk HPV HC2 DNA assay. Cervical specimens were preserved according to SurePath or ThinPrep protocols. LBC results were manually read. HC2 testing was performed on specimens with sufficient residual volume. Colposcopies and biopsies were performed on women who were VIA positive at the time of initial screening. Women with abnormal LBC or HC2 test results were called back for colposcopies and 4-quadrant cervical biopsies. RESULTS: Of 2005 eligible women, 972 were tested by SurePath and 1033 by ThinPrep. Compared with SurePath samples, ThinPrep samples had higher rates of unsatisfactory cytology (0.2% for SurePath and 1.5% for ThinPrep) and insufficient residual volume for HC2 (0.0% for SurePath and 18.2% for ThinPrep). SurePath samples yielded higher sensitivities and similar specificities for LBC and HC2 testing of residual specimens, but these differences were not determined to be significant by area-under-the-curve analysis (LBC performance: 0.89 for SurePath and 0.85 for ThinPrep; HC2 performance: 0.91 for SurePath and 0.89 for ThinPrep). CONCLUSIONS: Both methods yielded similar validity in detecting significant cervical lesions. However, SurePath samples yielded higher rates of satisfactory LBC slides and sufficient residual volume for HC2.

Aspects of prophylactic vaccination against cervical cancer and other human papillomavirus-related cancers in developing countries.

Cervical cancer and other human papillomavirus- (HPV-) related cancers are preventable, but preventive measures implemented in developing countries and especially in low-income rural regions have not been effective. Cervical cancer burden derived from sexually transmitted HPV infections is the heaviest in developing countries, and a dramatic increase in the number of cervical cancer cases is predicted, if no intervention is implemented in the near future. HPV vaccines offer an efficient way to prevent related cancers. Recently implemented school-based HPV vaccination demonstration programmes can help tackle the challenges linked with vaccine coverage, and access to vaccination and health services, but prevention strategies need to be modified according to regional characteristics. In urban regions WHO-recommended vaccination strategies might be enough to significantly reduce HPV-related disease burden, but in the rural regions additional vaccination strategies, vaccinating both sexes rather than only females when school attendance is the highest and applying a two-dose regime, need to be considered. From the point of view of both public health and ethics identification of the most effective prevention strategies is pivotal, especially when access to health services is limited. Considering cost-effectiveness versus justice further research on optional vaccination strategies is warranted.

Association of elevated E6 oncoprotein with grade of cervical neoplasia using PDZ interaction-mediated precipitation of E6.

OBJECTIVE: To determine the expression of human papillomavirus (HPV) type 16 E6 oncoprotein in cervical specimens of women with and without cervical intraepithelial neoplasia (CIN). MATERIALS AND METHODS: Cervical specimens from 2,530 unscreened women aged 30 to 54 years from Shanxi, China, were obtained. All women were assessed by liquid-based cytology, high-risk HPV DNA tests, and colposcopy with directed biopsy and endocervical curettage as necessary. Women with abnormal cytologic results or positive HPV DNA results were recalled for colposcopy, 4-quadrant cervical biopsies, and endocervical curettage. Women with biopsy-proven CIN and cancer and a convenience sample of HC2-positive, disease-negative women were tested for the presence of HPV-16 infection via HPV-16 E6 DNA-specific polymerase chain reaction. A PDZ interaction-mediated E6 oncoprotein precipitation method followed by E6-specific Western blot was performed on specimens from women with HPV-16 infections. Associations between elevated expression of E6 oncoprotein and CIN 2 and 3 were determined using logistic regression and a reference category of CIN 1 and disease-negative. RESULTS: A significant trend for the detection of HPV-16 E6 oncoprotein in specimen of women with proven HPV-16 infection was determined: 0% (0/12), 12.5% (1/8), 36.4% (4/11), and 42.9% (3/7) of those with negative findings, CIN 1, 2, and 3, respectively (p = .01). Compared with the category combining negative findings and CIN 1, detection of E6 oncoprotein was associated with CIN 2 (odds ratio = 10.9, p = .05) and CIN 3 (odds ratio = 14.3, p = .04). CONCLUSIONS: There is a significant association between elevated expression of E6 oncoprotein and grade of CIN. This finding seems consistent with the role played by E6 oncoprotein in carcinogenesis.

Expectant management versus immediate treatment for low-grade cervical intraepithelial neoplasia : a randomized trial in Canada and Brazil.

BACKGROUND: The optimal management strategy for women with low-grade biopsy-proven cervical intraepithelial neoplasia (CIN) is not clear. Our objective was to compare the effectiveness of regular colposcopic follow-up and treatment of progressive disease only versus immediate treatment. METHODS: Data were accrued between November 2000 and March 2006 for a noninferiority randomized clinical trial of 415 women with biopsy-proven grade 1 CIN from 8 Canadian and 2 Brazilian colposcopy clinics. Subjects were randomly assigned to either undergo immediate treatment with a loop electrical excision procedure (LEEP) or receive regular colposcopic follow-up for 18 months. The primary outcome was progression of disease to CIN 2 to 3 was based on histology obtained during 18 months of follow-up. Treatments were compared using differences of proportion with a 9% noninferiority margin. Analysis was conducted on the basis of intention-to-treat. RESULTS: An initial LEEP was performed on 179 women. Disease progression was found in 32. Easily controlled vaginal bleeding occurred in 16 (8.9%). During follow-up, disease progression was identified in 3 (1.7%) women in the immediate treatment arm and 9 (4.4%) in the colposcopic follow-up arm-a tolerable difference of 2.7% with 1-sided 95% confidence interval (CI) upper limit of 6.0%. Compliance with all 3 follow-up visits was 61% overall, but significantly worse in women ≤30 years of age (P < .05). CONCLUSIONS: The risk of progression to CIN grade 2 or 3 or cancer over 18 months was similar in the 2 treatment groups. In Canada and Brazil, follow-up for 18 months is a reasonable management strategy for women with persistent low-grade cytology who are found to have grade 1 CIN on referral for colposcopy and cervical biopsy.

Performance of high-risk human papillomavirus DNA testing as a primary screen for cervical cancer: a pooled analysis of individual patient data from 17 population-based studies from China.

BACKGROUND: Controversy remains over whether high-risk human papillomavirus (HPV) DNA testing should be used as a primary screen for cervical cancer. The aims of our study were to assess whether HPV DNA testing could be applied to cervical-cancer screening programmes in China, as well as other similar developing countries. METHODS: We did a pooled analysis of population-based cervical cancer screening studies done in mainland China from 1999 to 2008 with concurrent HPV DNA testing (Hybrid Capture 2 assay; Qiagen, Gaithersburg, MD, USA), liquid-based cytology (LBC), and visual inspection with acetic acid (VIA). Eligible women were sexually active, not pregnant, had an intact uterus, and had no history of cervical intraepithelial neoplasia (CIN), cervical cancer, or pelvic irradiation. All women positive for any test were referred for colposcopy and biopsy. Cervical lesions were diagnosed by directed or random biopsy. We assessed the diagnostic accuracy of HPV DNA testing for the detection of CIN grade 3 or greater. FINDINGS: 30,371 women from 17 cross-sectional, population-based studies in various parts of China were screened. 1523 women were subsequently excluded because of inadequate HPV DNA specimens or they did not have a biopsy taken, which included women with atypical squamous cells of undetermined significance; low-grade squamous intraepithelial lesion or worse; positive HPV, negative cytology, and missing or positive colposcopy results; and unsatisfactory cytology results. HPV DNA testing had a higher sensitivity of 97·5% (95% CI 95·7-98·7) for detection of CIN grade 3 or worse, and a lower specificity of 85·1% (82·3-87·9), compared with cytology (sensitivity 87·9% [95% CI 84·7-90·7], specificity 94·7% [93·5-96·0]) and VIA (54·6% [48·0-61·2], 89·9% [86·8-93·0]). Sensitivity did not vary by study or age (<35 years, 35-49 years, ≥50 years); however, specificity did vary with age (p<0·0001) and was highest in women younger than 35 years (89·4%; 95% CI 86·1-91·5). An increase in the positive cutoff point from the manufacturer recommended 1 pg/mL to 2 pg/mL led to a decrease in the overall HPV DNA positivity from 16·3% to 13·9% (p<0·0001), which could result in a decrease in referral rates, although sensitivity was slightly lower (97·5% to 95·2%). An increase in the cutoff point to 10 pg/mL in women younger than 35 years maintained a high sensitivity 97·7% (95% CI 87·7-99·9) and increased specificity to 93·5% (95% CI 91·9-94·6). INTERPRETATION: HPV DNA testing is highly sensitive and moderately specific for CIN grade 3 or worse, with consistent results across study sites and age groups-including women younger than 35 years. A rise in the cutoff point might be beneficial for future screening programmes in China, especially when screening women younger than 35 years.

Cost-effectiveness analysis of cervical cancer prevention based on a rapid human papillomavirus screening test in a high-risk region of China.

This study assessed the cost-effectiveness of a new, rapid human papillomavirus (HPV)-DNA screening test for cervical cancer prevention in the high-risk region of Shanxi, China. Using micro-costing methods, we estimated the resources needed to implement preventive strategies using cervical cytology or HPV-DNA testing, including the Hybrid Capture 2 (hc2) test (QIAGEN Corp., Gaithersburg, MD) and the rapid HPV-DNA careHPV test (QIAGEN). Data were used in a previously published model and empirically calibrated to country-specific epidemiological data. Strategies differed by initial test, targeted age, frequency of screening, number of clinic visits required (1, 2 or 3) and service delivery setting (national, county and township levels). Outcomes included lifetime risk of cancer, years of life saved (YLS), lifetime costs and incremental cost-effectiveness ratios (cost per YLS). For all screening frequencies, the most efficient strategy used 2-visit rapid HPV-DNA testing at the county level, including screening and diagnostics in the first visit, and treatment in the second visit. Screening at ages 35, 40 and 45 reduced cancer risk by 50% among women compliant with all 3 screening rounds, and was US$ 150 per YLS, compared with this same strategy applied twice per lifetime. This would be considered very cost-effective evaluated against China's per-capita gross domestic product (US$ 1,702). By enhancing the linkage between screening and treatment through a reduced number of visits, rapid HPV-DNA testing 3 times per lifetime is more effective than traditional cytology, and is likely to be cost-effective in high-risk regions of China.

Human papillomavirus testing and cervical cytology in primary screening for cervical cancer among women in rural China: comparison of sensitivity, specificity, and frequency of referral.

The causal relationship between persistent high-risk human papillomavirus infection and cervical cancer is widely accepted. HR-HPV DNA testing, alone or in combination with Pap smear testing, may have a role in primary screening. The screening results (VIA, VILI, Pap, and HR-HPV DNA) of 9,057 women in rural China were analyzed to determine the screening performance for the detection of CIN3+. All screening strategies had comparable AUCs (0.9). Cotesting strategies had the overall highest sensitivity for CIN3+ (99.4%), followed by HR-HPV DNA testing alone (96.3%), Pap alone (80.2%), and reflex testing (75.4%). Reflex testing had the highest specificity (96.7%), followed by Pap alone (93.3%), HR-HPV DNA testing alone (85.5%), and both cotesting strategies (LSIL: 84.8%, HSIL: 84.8%). Of the single-test strategies, HR-HPV DNA testing had a higher sensitivity (96.3% vs. 80.2%) compared with Pap testing. The specificity of the Pap test was higher (93.3% vs. 85.5%) and it had a lower percent referred for colposcopy (7.8% vs. 15.8%) than HR-HPV DNA testing. HR-HPV DNA testing with a 10.0 cutoff point (relative light units/cutoff ratio) had a sensitivity (85.2%) and specificity (90.6%) estimate comparable to Pap testing. A single-test primary screening strategy with adequate performance would permit less frequent screening and be most appropriate. Of the primary screening strategies investigated in this setting in China, the performance of HR-HPV DNA testing with an increased cutoff-point might best meet these criteria.

New technologies in cervical cancer screening.

A shift to a molecular approach to cervical cancer screening is the most likely solution to the goals of improved screening in both the developed and developing world. The impetus for new screening technologies in the developed world is predominately driven by the need to increase positive predictive value and reduce over-management of low-grade and often transient abnormalities (i.e., increase specificity). Rapid tests, where results can be given to a patient within the same visit, are anticipated to have the greatest impact in low resource settings in low and middle income countries (and in disadvantaged sub-populations in high-income countries) where substantial loss to follow up cripples the effectiveness of cervical cancer screening programs. Clinical validation will be required before these tests are implemented in routine screening programs.

A new HPV-DNA test for cervical-cancer screening in developing regions: a cross-sectional study of clinical accuracy in rural China.

BACKGROUND: A new test (careHPV; QIAGEN, Gaithersburg, MD, USA) has been developed to detect 14 high-risk types of carcinogenic human papillomavirus (HPV) in about 2.5 h, to screen women in developing regions for cervical intraepithelial neoplasia (CIN). We did a cross-sectional study to assess the clinical accuracy of careHPV as a rapid screening test in two county hospitals in rural China. METHODS: From May 10 to June 15, 2007, the careHPV test was done locally by use of self-obtained vaginal and provider-obtained cervical specimens from a screening population-based set of 2530 women aged 30 to 54 years in Shanxi province, China. All women were assessed by visual inspection with acetic acid (VIA), Digene High-Risk HPV HC2 DNA Test (HC2), liquid-based cytology, and colposcopy with directed biopsy and endocervical curettage as necessary. In 2388 women with complete data, 441 women with negative colposcopy, but unsatisfactory or abnormal cytology or who were positive on HC2 or the new careHPV test, were recalled for a second colposcopy, four-quadrant cervical biopsies, and endocervical curettage. An absence of independence between the tests was not adjusted for and the Bonferroni correction was used for multiple comparisons. FINDINGS: Complete data were available for 2388 (94.4%) women. 70 women had CIN2+ (moderate or severe CIN or cancer), of whom 23 had CIN3+. By use of CIN2+ as the reference standard and area-under-the-curve analysis with a two-sided alpha error level of 0.0083, the sensitivities and specificities of the careHPV test for a cut-off ratio cut-point of 0.5 relative light units, were 90.0% (95% CI 83.0-97.0) and 84.2% (82.7-85.7), respectively, on cervical specimens, and 81.4% (72.3-90.5) and 82.4% (80.8-83.9), respectively, on vaginal specimens (areas under the curve not significantly different, p=0.0596), compared with 41.4% (29.9-53.0) and 94.5% (93.6-95.4) for VIA (areas under the curve significantly different, p=0.0001 and p=0.0031, for cervical and vaginal-specimen comparisons for the careHPV test, respectively). The sensitivity and specificity of HC2 for cervical specimens were 97.1% (93.2-100) and 85.6% (84.2-87.1), respectively (areas under the curve not significantly different from the careHPV test on cervical specimens, p=0.0163). INTERPRETATION: The careHPV test is promising as a primary screening method for cervical-cancer prevention in low-resource regions.

Is magnification necessary to confirm visual inspection of cervical abnormalities? A randomized trial in Peru.

OBJECTIVES: Cervical cancer is the leading cause of cancer death among women in developing countries. This study was designed to evaluate whether visual inspection with acetic acid and magnification (VIAM) improved confirmation of cervical lesions as compared to confirmation with visual inspection with acetic acid (VIA) without magnification when used by physicians. METHODS: From April-December 2004, women in San Martin, Peru, who were referred as VIA-positive by an "obstetriz" (a professional midwife with 6 years of university training) were randomized into two groups for confirmatory screening by a physician using either VIA or VIAM with an AviScope, a hand-held 4x magnification scope with a green light source. The reference standard for the presence or absence of cervical neoplasia was colposcopy and directed biopsy, as required. RESULTS: A total of 358 women participated in the study; 161 had a confirmatory examination with VIAM and 159 with VIA. Sensitivity for low- or high-grade lesions was 68% with VIA and 77% with VIAM, and specificity was 62% with VIA and 63% with VIAM; however, these differences were not statistically significant. CONCLUSIONS: For settings where physician confirmation of cervical abnormalities identified through visual inspection is required and available, this study demonstrates that VIAM had no significant advantage over VIA.

Is magnification necessary to confirm visual inspection of cervical abnormalities? A randomized trial in Peru

OBJECTIVES: Cervical cancer is the leading cause of cancer death among women in developing countries. This study was designed to evaluate whether visual inspection with acetic acid and magnification (VIAM) improved confirmation of cervical lesions as compared to confirmation with visual inspection with acetic acid (VIA) without magnification when used by physicians. METHODS: From April-December 2004, women in San Martin, Peru, who were referred as VIA-positive by an "obstetriz" (a professional midwife with 6 years of university training) were randomized into two groups for confirmatory screening by a physician using either VIA or VIAM with an AviScope,TM a hand-held 4x magnification scope with a green light source. The reference standard for the presence or absence of cervical neoplasia was colposcopy and directed biopsy, as required. RESULTS: A total of 358 women participated in the study; 161 had a confirmatory examination with VIAM and 159 with VIA. Sensitivity for low- or high-grade lesions was 68 percent with VIA and 77 percent with VIAM, and specificity was 62 percent with VIA and 63 percent with VIAM; however, these differences were not statistically significant. CONCLUSIONS: For settings where physician confirmation of cervical abnormalities identified through visual inspection is required and available, this study demonstrates that VIAM had no significant advantage over VIA.

OBJETIVOS:En los países en desarrollo, el cáncer cervicouterino es la principal causa de muerte por cáncer en mujeres. Este estudio se diseñó para determinar si se puede mejorar la confirmación de lesiones cervicouterinas con la inspección visual con ácido acético y amplificación (VIAM) en comparación con la inspección visual con ácido acético (VIA) sin amplificación, cuando ambas las realizan médicos generales. MÉTODOS:Las mujeres de San Martín, Perú, con diagnóstico positivo mediante VIA realizado por una obstetriz (enfermera graduada con seis años de entrenamiento universitarios) entre abril y diciembre de 2004 se dividieron aleatoriamente en dos grupos para el diagnóstico confirmatorio realizado por médicos generales mediante VIA o VIAM, este último con un AviScopeTM, un dispositivo manual con lente monocular de amplificación 4X y fuente luz verde. Como método estándar de referencia para definir la presencia o ausencia de neoplasia cervicouterina se emplearon la colposcopia y la biopsia dirigida, según el caso. RESULTADOS:En el estudio participaron 358 mujeres, de ellas 161 pasaron la confirmación por VIAM y 159 por VIA. La sensibilidad para las lesiones de bajo y alto grados fue de 68 por ciento con VIA y de 77 por ciento con VIAM, mientras la especificidad fue de 62 por ciento por VIA y de 63 por ciento por VIAM; estas diferencias no tuvieron significación estadística. CONCLUSIONES:Se demostró que la VIAM no presentó ventajas significativas sobre la VIA en los casos en que se requiere y está disponible la confirmación de las lesiones del cuello uterino por un médico general.

Effect of cough technique and cryogen gas on temperatures achieved during simulated cryotherapy.

BACKGROUND: Cryotherapy is often used to treat cervical precancer in developing countries. There are different methods and cryogen gases used for cryotherapy, including the freeze-flush-freeze (cough) technique employed to minimize gas blockage. However, there is limited information to compare their effectiveness. METHODS: Using a tissue model, we compared temperature-time curves for four cryotherapy methods: uninterrupted freezing with nitrous oxide (N2O) and carbon dioxide (CO2), and two methods using a standard and extended version of the cough technique with CO2. RESULTS: Uninterrupted freezing with both N2O and CO2 produced tissue temperatures less than -20 degrees C (-40 degrees C and -30 degrees C respectively). CO2 cryotherapy procedures using the two cough techniques produced temperatures greater than -20 degrees C in the model tissue. CONCLUSION: CO2 cryotherapy using the cough technique may not achieve sufficiently low temperatures to produce the desired therapeutic effect. Other alternatives to the prevention of gas blockage should be developed.

Preliminary report of a gas conditioner to improve operational reliability of cryotherapy in developing countries.

BACKGROUND: Cryotherapy is a safe, affordable, and effective method of treatment for cervical intraepithelial neoplasia. In some low-resource settings, environmental conditions or qualities of the refrigerant gas can lead to blockage of cryotherapy equipment, terminating treatment. A prototype of a gas conditioner to prevent operational failure was designed, built, and field tested. METHODS: The prototype conditioner device consists of an expansion chamber that filters and dries the refrigerant gas. Users in Peru and Kenya reported on their experience with the prototype conditioner. In Ghana, simulated cryotherapy procedures were used to test the effects of the prototype conditioner, as well as the commonly used "cough technique." RESULTS: Anecdotal reports from field use of the device were favorable. During simulated cryotherapy, the prevalence of blockage during freezing were 0% (0/25) with the device alone, 23.3% (7/30) with the cough technique alone, 5.9% (1/17) with both, and 55.2% (16/29) with neither (Pearson's Chi square = 26.6, df = 3, p < 0.001 (comparison amongst all groups)). CONCLUSION: This prototype design of a cryotherapy gas conditioner is a potential solution for low-resource settings that are experiencing cryotherapy device malfunction.