Oral contraceptive use and the incidence of cervical intraepithelial neoplasia

Contraceptive strategies for reducing the risk of reproductive cancers

Reproductive cancers, encompassing various malignancies like endometrial, ovarian, cervical cancer, and gestational trophoblastic neoplasia, pose a significant global health burden. Understanding their patterns is vital for effective prevention and management. Contraceptives show a protective effect against some of these cancers. This clinical guidance document aims to elucidate the disease burden of reproductive cancers and the evidence supporting contraceptive methods in prevention and management. Regional disparities in incidence and mortality highlight the urgent need for targeted interventions, particularly in low-resource settings. Healthcare providers must weigh individual risk profiles and medical eligibility criteria when discussing contraceptive options. Enhanced health literacy through direct patient education is essential for leveraging low-cost behavioral interventions to mitigate reproductive cancer risks.

Disparities in Cervical Cancer Incidence and Mortality: Can Epigenetics Contribute to Eliminating Disparities?

Screening for uterine cervical intraepithelial neoplasia (CIN) followed by aggressive treatment has reduced invasive cervical cancer (ICC) incidence and mortality. However, ICC cases and carcinoma in situ (CIS) continue to be diagnosed annually in the United States, with minorities bearing the brunt of this burden. Because ICC peak incidence and mortality are 10-15 years earlier than other solid cancers, the number of potential years of life lost to this cancer is substantial. Screening for early signs of CIN is still the mainstay of many cervical cancer control programs. However, the accuracy of existing screening tests remains suboptimal. Changes in epigenetic patterns that occur as a result of human papillomavirus infection contribute to CIN progression to cancer, and can be harnessed to improve existing screening tests. However, this requires a concerted effort to identify the epigenomic landscape that is reliably altered by HPV infection specific to ICC, distinct from transient changes.

Cervical cancer and hormonal contraceptives: collaborative reanalysis of individual data for 16,573 women with cervical cancer and 35,509 women without cervical cancer from 24 epidemiological studies

BACKGROUND

Combined oral contraceptives are classified by the International Agency for Research on Cancer as a cause of cervical cancer. As the incidence of cervical cancer increases with age, the public-health implications of this association depend largely on the persistence of effects long after use of oral contraceptives has ceased. Information from 24 studies worldwide is pooled here to investigate the association between cervical carcinoma and pattern of oral contraceptive use.

METHODS

Individual data for 16,573 women with cervical cancer and 35,509 without cervical cancer were reanalysed centrally. Relative risks of cervical cancer were estimated by conditional logistic regression, stratifying by study, age, number of sexual partners, age at first intercourse, parity, smoking, and screening.

FINDINGS

Among current users of oral contraceptives the risk of invasive cervical cancer increased with increasing duration of use (relative risk for 5 or more years' use versus never use, 1.90 [95% CI 1.69-2.13]). The risk declined after use ceased, and by 10 or more years had returned to that of never users. A similar pattern of risk was seen both for invasive and in-situ cancer, and in women who tested positive for high-risk human papillomavirus. Relative risk did not vary substantially between women with different characteristics.

INTERPRETATION

The relative risk of cervical cancer is increased in current users of oral contraceptives and declines after use ceases. 10 years' use of oral contraceptives from around age 20 to 30 years is estimated to increase the cumulative incidence of invasive cervical cancer by age 50 from 7.3 to 8.3 per 1000 in less developed countries and from 3.8 to 4.5 per 1000 in more developed countries.

Altered urinary profiles of polyamines and endogenous steroids in patients with benign cervical disease and cervical cancer

The risk of cancer of the cervix is linked with sexual behavior. Although infectious agents, such as human papillomaviruses (HPVs) are implicated, these alone may be insufficient to induce the disease. We investigated the potential role of estrogen, androgen, and polyamine metabolism as co-factors in the development of cervical cancer. We obtained urine samples from patients with benign cervical disease (n=18) and cervical cancer (n=18) and from age-matched normal female subjects (n=25). For 11 polyamine determination, an improved and sensitive gas-chromatographic with nitrogen/phosphorus-detection (GC/NPD) procedure was used. The urinary levels of 25 androgens and corticoids and 16 estrogens were quantitatively determined by gas chromatography-mass spectrometry-selected ion-monitoring (GC/MS/SIM). In the patients with cervical cancer, the ratio of 16alpha-hydroxy estrone (16alpha-OH E1)/2-hydroxy estrone (2-OH E1), putrescine (Put)/N(1)-acetylspermidine (N(1)-acSpd) and 5beta-tetrahydrocortisol (THF)/5alpha-tetrahydrocortisol (5alpha-THF) were significantly increased in comparison to the values of the normal controls. These data suggest: (1) an increase of 16alpha-hydroxylation in estrogen metabolism; (2) the high activity of polyamine oxidase (PAO) in polyamine metabolism; and (3) the low activity of 5alpha-reductase in androgen metabolism may play a significant role in the development of cervical cancer. Although additional research is necessary, the combination of 16alpha-OH E1/2-OH E1 and THF/5alpha-THF may provide a dual marker for the discrimination of benign cervical disease and cervical cancer.

Hormonal and barrier methods of contraception, oncogenic human papillomaviruses, and cervical squamous intraepithelial lesion development

We assessed the influence of hormonal (oral, injectable, or levonorgestrel [Norplant, Wyeth-Ayerst, Philadelphia, PA]) and barrier methods of contraception on the risk of cervical squamous intraepithelial lesions (SIL), while adjusting for high-risk (HR) HPV infection. Subjects were women receiving family planning services through the state health department clinics from 1995 to 1998. We selected 60 cases with high-grade cervical/SIL (HSIL) and 316 with low-grade cervical/SIL (LSIL) and controls (427 women with normal cervical cytology) and analyzed cervical DNA for HR-HPV, using Hybrid Capture I (Digene; Gaithersburg, MD). When assessing ever use, duration, recency, latency, and age at first use, neither oral contraceptives (OC), Norplant, nor injectable use was associated with an increased risk of SIL development after adjusting for age, age at first sexual intercourse, and HR-HPV positivity. Among HR-HPV-positive women, longer duration barrier method use was associated with a reduced risk of SIL. This finding has important clinical implications for SIL prevention among HR-HPV-infected women.

Risk factors for pre-cancerous lesions of the cervix

Studies on risk factors for pre-cancerous lesions of the uterine cervix have shown strong association with sexual practice. Women with multiple sexual partners and intercourse at early age are at high risk. A role of male partners in further enhancing the risk has been identified. All these support the hypothesis relating to a sexually transmissible aetiological agent. An extensive review of the literature on the risk factors for pre-cancerous lesions of cervix has been carried out. The risk factors were grouped into genital, sexual, chemical, dietary and life factors. Human papilloma virus (HPV) is the major infectious aetiological agent associated with the development of pre-cancerous lesions of cervix. Other co-factors such as multiple sexual partners of the male as well as the female and early age of first intercourse are also involved at the critical aetiological step of progression from low-grade to high-grade lesions. The role of other infectious agents in terms of supportive or interactive effects is not clear. No independent effect for herpes simplex virus 2 on risk is observed. Other risk factors include cigarette smoking, oral contraceptive usage, certain nutritional deficiencies and poor personal hygiene. However, it is not clear whether these factors operate independently from HPV. There is no consistency in the independent effect of these factors on the development of low- to high-grade lesions of cervix. There is a similarity in the patterns of risk between pre-cancerous lesions of the cervix and cervical cancer. Monogamy, late commencement of sexual activity, personal hygiene and use of barrier contraceptive methods help towards primary prevention. In the long-term, primary prevention of cervical neoplasia through HPV immunization of population may be a possibility.

Evaluation of the significance of polyamines and their oxidases in the aetiology of human cervical carcinoma

The risk of cancer of the cervix is linked with sexual behaviour. Although infectious agents such as human papillomaviruses (HPVs) are implicated, these alone may be insufficient to induce the disease. We have investigated the potential role of oxidation products of the polyamines spermine and spermidine and the diamine putrescine in seminal plasma (SP) as co-factors in the development of cervical cancer. These amines are oxidised by polyamine oxidase (PAO) and diamine oxidase (DAO) to generate oxygen radicals and hydrogen peroxide, reactive aldehydes and acrolein, which are likely to exert local mutagenic, cytotoxic and immunosuppressive effects in vivo. Using a chemiluminescence assay, we determined the levels of these amines in 187 samples of SP. Spermine plus spermidine, as substrates for PAO, were present in a range equivalent to 0-4.8 mg ml-1 spermine. Putrescine, as a substrate for DAO, was detectable in only 4 of 40 samples assayed (range 0-168 micrograms ml-1) and constitutes a minor component of the oxidisable content of SP. Cervical mucus (126 samples) was assayed for the presence of PAO and DAO. Both enzymes were present in 14.3% of the samples, PAO only in 21.4%, DAO only in 15.1% and neither enzyme in 49.2%. PAO levels ranged from 0 to 0.828 pmol peroxide generated min-1 mg-1 mucus and DAO levels ranged from 0 to 7.0 pmol peroxide generated min-1 mg-1 mucus. These results suggest that sexual activity in the absence of physical barrier contraception may lead to the generation of mutagenic and immunosuppressive polyamine oxidation products within the female genital tract. We thus propose that women with high levels of PAO and/or DAO in their cervical mucus may be at increased risk of cervical cancer, especially if the male partner's SP shows high polyamine levels. HPV infection may synergise with the effects of polyamine oxidation by suppressing apoptosis in keratinocytes carrying potentially oncogenic mutations, leading to the survival and proliferation of transformed cells in the cervix.

Women, contraception and STDs including HIV

It is estimated that eight million women are infected with the human immunodeficiency virus (HIV) worldwide. Heterosexual transmission is the predominant mode of HIV transmission on a global basis and is becoming increasingly important in the Western world. Women have long used contraceptives as a means of protection against an unwanted pregnancy, some of which may also protect against sexually transmitted disease (STD) including HIV. We review the relationship between contraceptive methods and STD acquisition and transmission; HIV acquisition and transmission; and the implications of contraceptive use, particularly regarding disease progression, in those women who are already infected with the virus. It is important for all women that protection against both unwanted pregnancy and HIV acquisition and transmission are considered together and not in isolation as nowhere is the argument for a broad based multi-disciplinary approach more cogent.

Dysplasia and HPV infection initially detected by DNA analysis in cytomorphologically normal cervical smears

OBJECTIVE

We examined the relationship between the risk of dysplasia and human papillomavirus (HPV) infection initially detected by DNA analysis in Japanese women with cytomorphologically normal cervical smears.

METHOD

We applied the polymerase chain reaction method to detect HPV DNA in 800 women and subsequently followed up 49 women positive for HPV DNA.

RESULTS

HPV 16 or HPV 18 DNA was detected in 53 (6.6%) of 800 women with normal smears (negative). During the follow-up period (23 months), the presence of HPV DNA could not be detected in 41 (83.7%) of 49 women after its initial presence. The remaining eight women had repeated HPV DNA, and four of these eight women had lesions that progressed to mild dysplasia.

CONCLUSION

The results indicated that some women with cytomorphologically normal smears may have HPV DNA which can be transient, and persistence of HPV types 16 or 18 DNA plays an important role in the pathogenesis of cervical dysplasia.

Cervical intraepithelial neoplasia in Jordan: A ten year retrospective cytoepidemiologic study

Occurrence of cervical intraepithelial neoplasia (CIN) was studied in 10,659 females attending obstetric and gynecology clinics in Jordan. The frequency rate of intraepithelial neoplasia was 1.1% in 7743 Jordanian females and 2916 non-Jordanian residents of younger age during the period from 1982 to 1991 inclusive. The incidence rate in 2649 Jordanian females, selected because they attended only for routine checkup, was 49 per 100,000. There were 121 CIN cases which were graded into Grade I (21%), II (48%) and III (31%) respectively. Histological grading correlated with cytology in 70% of the cases while in the remaining 30%, cytologic underrating by one grade was noted; evidence against any overdiagnosis of CIN in our series. Study of the human papillomavirus (HPV) was outside the scope of this effort. However, circumcision in male partners and marital status were associated with a lower frequency of CIN. Age at marriage and average duration, parity, breast feeding, the contraceptive pill, socioeconomic status and menstrual disorders showed no relationship to the frequency of CIN in our patients. Any differences in the latter between Jordanian and non-Jordanian females are believed due to cultural factors. Conization in 27 cases proved effective at 30 months' follow-up. Occurrence of CIN in Jordanian females appears substantial although much lower than that seen in high incidence zones, while its incidence in the general female population remains to be determined. This study shows for the first time the value of Papanicolaou (Pap) smears in Jordanian females over 20 years of age with special emphasis on those over 35 years of age attending obstetric and gynecology clinics.

Etiology of cervical cancer: current concepts

The data on the etiological factors presented here may enable us to suggest a synergism between the various factors associated with the pathogenesis of cervical cancer. Infection of the cervix by HPV 16/18 may result in persistence of viral DNA. The persistent HPV-DNA undergoes disruption at the E2 region, when integrated into the host genome. The transcriptional products E6 and E7 oncoproteins bind to and cause the degradation of p53 and Rb tumor-suppressor gene products. It is possible that, at that point, other cofactors may be involved in the progression toward a precancerous or cancerous condition. Those cofactors may include cigarette smoking, by introducing co-carcinogens to the tissue or by suppressing the local or systemic immune resistance similar to the effect of depressed immune resistance seen in AIDS or immunosuppression of transplant patients; hormones, by enhancing growth of HPV and transformation of HPV infected cells; low serum vitamin levels leading to decreased tissue resistance; or other infections causing local inflammation and the production of free radicals. CIN develops, leading eventually to cervical cancer.

Trichomonas vaginalis (TV) and human papillomavirus (HPV) infection and the incidence of cervical intraepithelial neoplasia (CIN) grade III

The temporal relationship between cervical infection with Trichomonas vaginalis (TV) or human papillomavirus (HPV) and the incidence rate of cervical intraepithelial neoplasia grade three (CIN III) was examined in a cohort of 43,016 Norwegian women. From 1980 to 1989, a cervico-vaginal infection from TV and HPV was diagnosed cytologically in 988 and 678 women, respectively. During the 181,240 person-years of observation, 440 cases of CIN III/cervical cancer developed. The age-adjusted incidence rates (IR) of CIN III were 225 per 100,000 person-years among women with no cytologic evidence of infection, 459 among women with TV infection, and 729 among women with HPV infection. A multiple regression model yielded a relative rate (RR) of CIN III of 2.1 (95 percent confidence interval [CI] = 1.3-3.4) among women with TV infection and 3.5 (CI = 1.9-6.6) among women with HPV infection, compared with women with neither infection. As CIN can be misclassified as HPV infection, the entry Pap-smears of 10 women with HPV infection who later developed CIN III were re-examined. Excluding the four discordant cases with the corresponding person-years decreased the RR of CIN III to 2.1 (CI = 0.9-4.8). Our report demonstrates the limitations of studies that rely only on cytologic detection of HPV infection. Nevertheless, the results support the hypothesis that HPV is a causal factor for CIN III lesions, and also display an association between TV infection and cervical neoplasia.