Risk of progression of cervical intraepithelial neoplasia grade 2 in human papillomavirus-vaccinated and unvaccinated women: a population-based cohort study

BACKGROUND

Many countries have implemented active surveillance (ie, leaving the lesion untreated) as an option among younger women with cervical intraepithelial neoplasia grade 2 because regression rates are high and excisional treatment increases the risk for preterm birth in subsequent pregnancies. However, early identification of women at increased risk for progression to cervical intraepithelial neoplasia grade 3 or worse is important to ensure timely treatment. Because women who have received a human papillomavirus vaccine have a lower risk for cervical cancer, they may have a lower risk for progression of untreated cervical intraepithelial neoplasia grade 2 to cervical intraepithelial neoplasia grade 3 or worse.

OBJECTIVE

This study aimed to investigate if women who received a human papillomavirus vaccine and who are undergoing active surveillance for cervical intraepithelial neoplasia grade 2 are less likely to progress to cervical intraepithelial neoplasia grade 3 or worse when compared with women who did not receive the vaccine.

STUDY DESIGN

We conducted a population-based cohort study in Denmark using data from national health registers. We identified all women aged 18 to 40 years who were undergoing active surveillance for cervical intraepithelial neoplasia grade 2 from January 1, 2007, to December 31, 2020. Women with a previous record of cervical intraepithelial neoplasia grade 2 or worse, hysterectomy, or a loop electrosurgical excision procedure were excluded. Exposure was defined as having received ≥1 dose of a human papillomavirus vaccine at least 1 year before the cervical intraepithelial neoplasia grade 2 diagnosis. We used cumulative incidence functions to estimate the risk for progression to cervical intraepithelial neoplasia grade 3 or worse within 28 months using hysterectomy, emigration, and death as competing events. We used modified Poisson regression to calculate crude and adjusted relative risks of progression during the 28-month surveillance period. Results were stratified by age at vaccination and adjusted for index cytology, disposable income, and educational level.

RESULTS

The study population consisted of 7904 women of whom 3867 (48.9%) were vaccinated at least 1 year before a diagnosis of cervical intraepithelial neoplasia grade 2. At the time of cervical intraepithelial neoplasia grade 2 diagnosis, women who were vaccinated were younger (median age, 25 years; interquartile range, 23-27 years) than those who were not (median age, 29 years; interquartile range, 25-33 years). The 28-month cumulative risk for cervical intraepithelial neoplasia grade 3 or worse was significantly lower among women who were vaccinated before the age of 15 years (22.9%; 95% confidence interval, 19.8-26.1) and between the ages of 15 and 20 years (31.5%; 95% confidence interval, 28.8-34.3) when compared with women who were not vaccinated (37.6%; 95% confidence interval, 36.1-39.1). Thus, when compared with women who were not vaccinated, those who were vaccinated before the age of 15 years had a 35% lower risk for progression to cervical intraepithelial neoplasia grade 3 or worse (adjusted relative risk, 0.65; 95% confidence interval, 0.57-0.75), whereas women who were vaccinated between the ages of 15 and 20 years had a 14% lower risk (adjusted relative risk, 0.86; 95% confidence interval, 0.79-0.95). For women who were vaccinated after the age of 20 years, the risk was comparable with that among women who were not vaccinated (adjusted relative risk, 1.02; 95% confidence interval, 0.96-1.09).

CONCLUSION

Women who were vaccinated and who were undergoing active surveillance for cervical intraepithelial neoplasia grade 2 had a lower risk for progression to cervical intraepithelial neoplasia grade 3 or worse during 28 months of follow-up when compared with women who were not vaccinated but only if the vaccine was administered by the age of 20 years. These findings may suggest that the human papillomavirus vaccination status can be used for risk stratification in clinical management of cervical intraepithelial neoplasia grade 2.

Insufficient training in colposcopy and loop electrosurgical excision procedure among residents

INTRODUCTION

Colposcopy is an important tool in the diagnostic work-up of women with an abnormal cervical smear. Unlike in other countries where colposcopy is mostly performed by certified colposcopists, in Denmark, colposcopy may be performed by residents in obstetrics and gynaecology (OB/Gyn). We aimed to evaluate training in colposcopy and loop electrosurgical excision procedure (LEEP) among Danish OB/Gyn residents.

METHODS

Two questionnaires were developed: one for OB/Gyn residents who are required to learn colposcopy and LEEP during their residency, and one for chief physicians who are responsible for providing their training. Questionnaires were distributed by e-mails and via social media from November to December 2021.

RESULTS

Among 120 eligible residents, 93 completed the questionnaire. The median age was 36 (interquartile range: 34-39) years. Most received training in colposcopy (84.9%), but the majority considered training to be insufficient (76.3%) and had low self-efficacy in performing colposcopy (72.0%). With respect to LEEP, most received training (84.9%), but nearly half considered that their training had been insufficient (43.0%) and had low self-efficacy in performing LEEP (49.5%).

CONCLUSIONS

Most Danish OB/Gyn residents receive insufficient training in colposcopy and LEEP, which demonstrates a need for a formal training programme for residents and their supervisors to ensure an appropriate level of training and adequate patient care.

FUNDING

Danish Association of Younger Gynaecologists and Obstetricians (FYGO).

TRIAL REGISTRATION

Not relevant.

Intact transmembrane isoforms of the neural cell adhesion molecule are released from the plasma membrane

Three soluble neural cell adhesion molecule (NCAM) polypeptide classes of M(r) values 190,000 (NCAM-s1), 135,000 (NCAM-s2) and 115,000-110,000 (NCAM-s3) have been demonstrated in rat brain and cerebrospinal fluid [Krog, Olsen, Dalseg, Roth and Bock (1992) J. Neurochem. 59, 838-847]. NCAM-s3 is known to arise from released glycosylphosphatidylinositol (GPI)-linked NCAM [He, Finne and Goridis (1987) J. Cell. Biol. 105, 2489-2500] as well as from extracellularly cleaved transmembrane NCAM isoforms [Nybroe, Linnemann and Bock (1989) J. Neurochem. 53, 1372-1378]. In this study the origin of NCAM-s1 and NCAM-s2 and the function of soluble NCAM forms were investigated. It was shown that all three soluble forms could be released from brain membranes with M(r) values identical to the three major membrane-associated forms: the large transmembrane 190,000-M(r) form (NCAM-A), the smaller transmembrane 135,000-M(r) form (NCAM-B) and the GPI-anchored 115,000-110,000-M(r) form (NCAM-C). A polyclonal antibody, directed against transmembrane and cytoplasmic epitopes common to NCAM-A and NCAM-B, was shown to react with NCAM-s1 and NCAM-s2. Furthermore, NCAM-B was shown to be shed in a presumably intact soluble form from membranes of cells transfected with this isoform. Thus, NCAM-s1 and NCAM-s2 probably represent intact released transmembrane NCAM-A and NCAM-B. The soluble transmembrane forms are likely to exist in vivo, as NCAM-s1 and NCAM-s2 were readily demonstrated in cerebrospinal fluid. By density-gradient centrifugation it was shown that shed transmembrane NCAM-B was present in fractions of high, as well as low, density, indicating that a fraction of the shed NCAM is associated with minor plasma membrane fragments. Finally, it was shown that isolated soluble NCAM inhibited cell binding to an immobilized NCAM substratum, attributing a pivotal role to soluble NCAM in vivo as a modulator of NCAM-mediated cell behaviour.

Age-related changes in expression of neural cell adhesion molecule (NCAM) in heart: a comparative study of newborn, adult and aged rats

The neural cell adhesion molecule (NCAM) has been implicated in cellular interactions involved in cardiac morphogenesis and innervation. In this study, expression of NCAM mRNA and protein was characterized in rat heart during postnatal development and aging (postnatal days 1, 10, 40, 270, and 730). Alternative splicing of NCAM mRNA was analyzed by Northern blotting using DNA oligonucleotide probes designed for demonstration of certain exons or exon combinations. Total NCAM mRNA was downregulated during postnatal development followed by upregulation in the aging heart. Three major NCAM mRNA classes of 6.7, 5.2 and 2.9 kb were expressed in newborn heart in approximately equal proportions. At all other ages, the mRNAs of 5.2 and 2.9 kb were more predominant than the 6.7 kb mRNA. During postnatal development and aging, expression of exon VASE was selectively downregulated in the 6.7 kb NCAM mRNA class, whereas it was clearly detectable in NCAM mRNA classes of 5.2 and 2.9 kb. Insertion of exons a and AAG between exons 12 and 13 was more pronounced in the 5.2 and 2.9 kb NCAM mRNAs than in the 6.7 kb mRNA at all ages. Insertions at the 12/13 junctions decreased in the 6.7 kb mRNA as compared to the 5.2 and 2.9 kb mRNAs during postnatal development. Quantification of NCAM protein by enzyme-linked immunosorbent assay showed that NCAM protein amount decreased from a level of 0.93 microgram NCAM/mg total protein at birth to postnatal day 40 where a level of 0.21 microgram NCAM/mg total protein was found. During aging, NCAM increased again to 0.34 micrograms NCAM/mg total protein at postnatal day 730. NCAM isoforms were studied by immunoblotting analysis. At all ages, the major NCAM isoforms of 190, 145 and 120 kDa were observed in heart, the 145 kDa isoform being predominant.(ABSTRACT TRUNCATED AT 250 WORDS)

Age-related changes in expression of the neural cell adhesion molecule in skeletal muscle: a comparative study of newborn, adult and aged rats

Neural cell adhesion molecule (NCAM) is expressed by muscle and involved in muscle-neuron and muscle-muscle cell interactions. The expression in muscle is regulated during myogenesis and by the state of innervation. In aged muscle, both neurogenic and myogenic degenerative processes occur. We here report quantitative and qualitative changes in NCAM protein and mRNA forms during aging in normal rat skeletal muscle. Determination of the amount of NCAM by e.l.i.s.a. showed that the level decreased from perinatal to adult age, followed by a considerable increase in 24-month-old rat muscle. Thus NCAM concentration in aged muscle was sixfold higher than in young adult muscle. In contrast with previous reports, NCAM polypeptides of 200, 145, 125 and 120 kDa were observed by immunoblotting throughout postnatal development and aging, the relative proportions of the individual NCAM polypeptides remaining virtually unchanged at all ages examined. However, changes in the extent of sialylation of NCAM were demonstrated. Even though the relative amounts of the various NCAM polypeptides were unchanged during aging, distinct changes in NCAM mRNA classes were observed. Three NCAM mRNA classes of 6.7, 5.2 and 2.9 kb were present in perinatal and young adult skeletal muscle, whereas only the 5.2 and 2.9 kb mRNA classes could be demonstrated in aged muscle. This indicates that metabolism of the various NCAM polypeptides is individually regulated during aging. Alternative splicing of NCAM mRNA in skeletal muscle was studied by Northern blotting using DNA oligonucleotide probes specifically hybridizing to selected exons or exon combinations. Exon VASE, which has previously been shown to be present in both brain and heart NCAM mRNA, was virtually absent from skeletal muscle at all ages studied. In contrast, the majority of NCAM mRNA in postnatal skeletal muscle was shown to contain extra exons inserted between exons 12 and 13. Of the various possible exon combinations at this splice site, the combinations 12-a-AAG-13 and 12-a-b seemed to be prevalent in postnatal skeletal muscle. No significant change in the relative proportion of these two exon combinations occurred during aging. The observed upregulation of NCAM protein in aged muscle supports the assumption that an increasing proportion of muscle fibres are denervated in aged muscle. Selective upregulation of the 5.2 and 2.9 kb mRNA forms have previously been demonstrated in muscle cell lines and in primary cultures of muscle cells during formation of myotubes in vitro, and this switch in NCAM mRNA classes has been suggested to correlate with myogenesis.(ABSTRACT TRUNCATED AT 250 WORDS)

Characterization of soluble neural cell adhesion molecule in rat brain, CSF, and plasma

The polypeptide composition and glycosylation of soluble isoforms of neural cell adhesion molecule (NCAM) in developing rat brain, CSF, and plasma were characterized. Soluble NCAM in rat brain consisted of several glycosylated isoforms. The degree of glycosylation was developmentally regulated. After desialylation, four polypeptides of M(r) values of approximately 190,000 (s1), 135,000 (s2), 115,000 (s3), and 110,000 (s4) were observed. Polypeptides s1, s2, and s3 were also present in CSF, whereas only s3 and s4 were observed in plasma. Treatment of soluble brain NCAM with N-glycosidase F, which removes N-linked carbohydrates, produced polypeptides of M(r) values of approximately 190,000, 125,000, and 108,000-97,000. The monoclonal antibody OB11, which recognizes an epitope on the cytoplasmic part of transmembrane forms of NCAM, did not react with any of the soluble isoforms. Purified soluble NCAM, consisting mainly of s3, contained an N-terminal sequence identical to that of membrane-associated NCAM. Gel filtration of s3 indicated that it was present as a dimer under the chosen conditions. NCAM-expressing glioma cells adhered specifically to immobilized soluble NCAM. This implies that functionally significant soluble forms of NCAM are present in the extracellular fluid.