Prevention, incidence, and survival of cervical cancer in Sweden
Sundqvist, Avalon LU
(2021)
In Lund University, Faculty of Medicine Doctoral Dissertation Series
- Abstract
- Cervical cancer is preventable by screening. In 1967, Sweden introduced a cervical screening program. Screening for high-risk human papillomavirus (hr-HPV), the causative factor of cervical cancer, is more sensitive than cytology and can be performed as a self-sample. Non-attendance to screening is a large risk factor for cervical cancer. Self-samples may improve screening attendance.
The aims of this thesis were: To analyze if the cervical screening program in Sweden can be improved by using vaginal self-samples and an HPV mRNA assay, with the main focus on screening non-attendees. To obtain knowledge if cervical cancer incidence and survival has changed since the implementation of the screening program.
Study I:... (More) - Cervical cancer is preventable by screening. In 1967, Sweden introduced a cervical screening program. Screening for high-risk human papillomavirus (hr-HPV), the causative factor of cervical cancer, is more sensitive than cytology and can be performed as a self-sample. Non-attendance to screening is a large risk factor for cervical cancer. Self-samples may improve screening attendance.
The aims of this thesis were: To analyze if the cervical screening program in Sweden can be improved by using vaginal self-samples and an HPV mRNA assay, with the main focus on screening non-attendees. To obtain knowledge if cervical cancer incidence and survival has changed since the implementation of the screening program.
Study I: Incidence and net survival according to morphology, age, and stage at diagnosis among women diagnosed with invasive cervical cancer between 1960 and 2014 were calculated. The age-standardized incidence of squamous cell carcinoma (SCC) decreased until the year 2000, while the incidence of adenocarcinoma (ADC) increased continuously. Age-standardized 5-year net survival increased. SCC and ADC did not statistically differ in net survival after 2012. Among women >75 years, long-term net survival has decreased since 1960.
Study II: The sensitivity and specificity of vaginal and urine self-samples compared to cervical samples analyzed by Aptima HPV mRNA assay were evaluated in a referral population. The sensitivity for detection of high-grade squamous intraepithelial lesions /adenocarcinoma in situ/cancer was 85.5% for the vaginal self-sample, 44.8% for the urinary sample, 100.0% for the cervical sample and 81.7% for cytology.
Study III-V: Screening non-attendees or women in the upper age screening limit were sent a vaginal self-sampling kit by mail. In study III, 1,000 women, aged 69-70 years, received a kit. In study IV and V, 6,023 and 19,766 women, aged 30-70 years, received a kit. Returned samples were analyzed for HPV mRNA by Aptima assay. HPV-positive women were invited to follow-up. The response rate of the self-sample was 43.3%, 13.2% and 18.5% for study III, IV and V respectively. The HPV prevalence was 6.2% in study III, and no cases of high-grade dysplasia/cancer were diagnosed. The HPV prevalence was 9.9% and 11.3% in study IV and V respectively. In study IV, the prevalence of cervical cancer was almost seven times higher compared to organized screening, but in study V the prevalence of cancer was not increased.
Conclusion: This thesis demonstrated that the incidence of SCC, but not ADC, has decreased since 1960. SCC and ADC did not statistically differ in net survival after 2012. The decreased long-term net survival among women >75 years of age suggests the need for prolonged HPV screening up to 75 years of age. Self-sampling is a promising method since it was accepted among women 69-70 years old, and it increased the attendance to cervical screening by almost one fifth among non-attendees. A vaginal HPV self-sample analyzed by Aptima mRNA assay showed a similar sensitivity as routine cytology and may be used to reach screening non-attendees. Among screening non-attendees and women in the upper age screening limit, around one in 10-20 tested positive for HPV mRNA, with risk of development of cervical dysplasia, although the prevalence of cervical cancer varied between the studies. (Less)
Please use this url to cite or link to this publication:
https://lup.lub.lu.se/record/06e9f26b-7d5d-45bc-9406-a87004c858f6
- author
- Sundqvist, Avalon
LU
- supervisor
- opponent
-
- Professor Olovsson, Matts, Department of Women's and Children's Health, Uppsala University
- organization
- publishing date
- 2021
- type
- Thesis
- publication status
- published
- subject
- keywords
- Cervical cancer, Human papillomavirus, Screening, Self-sampling, Incidence, Net survival
- in
- Lund University, Faculty of Medicine Doctoral Dissertation Series
- issue
- 2021:124
- pages
- 95 pages
- publisher
- Lund University, Faculty of Medicine
- defense location
- Föreläsningssalen KK, vån 3, Klinikgatan 12, Universitetssjukhuset i Lund. Join by Zoom: https://lu-se.zoom.us/j/63250731501
- defense date
- 2021-11-26 09:00:00
- ISSN
- 1652-8220
- ISBN
- 978-91-8021-131-4
- language
- English
- LU publication?
- yes
- id
- 06e9f26b-7d5d-45bc-9406-a87004c858f6
- date added to LUP
- 2021-11-05 14:54:21
- date last changed
- 2021-11-10 11:14:02
@phdthesis{06e9f26b-7d5d-45bc-9406-a87004c858f6,
abstract = {{Cervical cancer is preventable by screening. In 1967, Sweden introduced a cervical screening program. Screening for high-risk human papillomavirus (hr-HPV), the causative factor of cervical cancer, is more sensitive than cytology and can be performed as a self-sample. Non-attendance to screening is a large risk factor for cervical cancer. Self-samples may improve screening attendance. <br/><br/>The aims of this thesis were: To analyze if the cervical screening program in Sweden can be improved by using vaginal self-samples and an HPV mRNA assay, with the main focus on screening non-attendees. To obtain knowledge if cervical cancer incidence and survival has changed since the implementation of the screening program. <br/><br/>Study I: Incidence and net survival according to morphology, age, and stage at diagnosis among women diagnosed with invasive cervical cancer between 1960 and 2014 were calculated. The age-standardized incidence of squamous cell carcinoma (SCC) decreased until the year 2000, while the incidence of adenocarcinoma (ADC) increased continuously. Age-standardized 5-year net survival increased. SCC and ADC did not statistically differ in net survival after 2012. Among women >75 years, long-term net survival has decreased since 1960. <br/><br/>Study II: The sensitivity and specificity of vaginal and urine self-samples compared to cervical samples analyzed by Aptima HPV mRNA assay were evaluated in a referral population. The sensitivity for detection of high-grade squamous intraepithelial lesions /adenocarcinoma in situ/cancer was 85.5% for the vaginal self-sample, 44.8% for the urinary sample, 100.0% for the cervical sample and 81.7% for cytology. <br/><br/>Study III-V: Screening non-attendees or women in the upper age screening limit were sent a vaginal self-sampling kit by mail. In study III, 1,000 women, aged 69-70 years, received a kit. In study IV and V, 6,023 and 19,766 women, aged 30-70 years, received a kit. Returned samples were analyzed for HPV mRNA by Aptima assay. HPV-positive women were invited to follow-up. The response rate of the self-sample was 43.3%, 13.2% and 18.5% for study III, IV and V respectively. The HPV prevalence was 6.2% in study III, and no cases of high-grade dysplasia/cancer were diagnosed. The HPV prevalence was 9.9% and 11.3% in study IV and V respectively. In study IV, the prevalence of cervical cancer was almost seven times higher compared to organized screening, but in study V the prevalence of cancer was not increased. <br/><br/>Conclusion: This thesis demonstrated that the incidence of SCC, but not ADC, has decreased since 1960. SCC and ADC did not statistically differ in net survival after 2012. The decreased long-term net survival among women >75 years of age suggests the need for prolonged HPV screening up to 75 years of age. Self-sampling is a promising method since it was accepted among women 69-70 years old, and it increased the attendance to cervical screening by almost one fifth among non-attendees. A vaginal HPV self-sample analyzed by Aptima mRNA assay showed a similar sensitivity as routine cytology and may be used to reach screening non-attendees. Among screening non-attendees and women in the upper age screening limit, around one in 10-20 tested positive for HPV mRNA, with risk of development of cervical dysplasia, although the prevalence of cervical cancer varied between the studies.}},
author = {{Sundqvist, Avalon}},
isbn = {{978-91-8021-131-4}},
issn = {{1652-8220}},
keywords = {{Cervical cancer; Human papillomavirus; Screening; Self-sampling; Incidence; Net survival}},
language = {{eng}},
number = {{2021:124}},
publisher = {{Lund University, Faculty of Medicine}},
school = {{Lund University}},
series = {{Lund University, Faculty of Medicine Doctoral Dissertation Series}},
title = {{Prevention, incidence, and survival of cervical cancer in Sweden}},
url = {{https://lup.lub.lu.se/search/files/109355714/e_spik_ex_Avalon.pdf}},
year = {{2021}},
}