Endometrial cancer and hormone-replacement therapy in the Million Women Study

BACKGROUND

Postmenopausal women who use hormone-replacement therapy (HRT) containing oestrogen alone are at increased risk of endometrial cancer. To minimise this risk, many HRT users who have not had a hysterectomy use combined oestrogen-progestagen preparations or tibolone. Limited information is available on the incidence of endometrial cancer in users of these therapies.

METHODS

716,738 postmenopausal women in the UK without previous cancer or previous hysterectomy were recruited into the Million Women Study in 1996-2001, provided information about their use of HRT and other personal details, and were followed up for an average of 3.4 years, during which time 1320 incident endometrial cancers were diagnosed.

FINDINGS

320,953 women (45%) reported at recruitment that they had used HRT, among whom 69,577 (22%) last used continuous combined therapy (progestagen added daily to oestrogen), 145,486 (45%) last used cyclic combined therapy (progestagen added to oestrogen, usually for 10-14 days per month), 28,028 (9%) last used tibolone, and 14,204 (4%) last used oestrogen-only HRT. These HRT types had sharply contrasting effects on the overall risk of endometrial cancer (p<0.0001 for heterogeneity). Compared with never users of HRT, risk was: reduced with last use of continuous combined preparations (relative risk 0.71 [95% CI 0.56-0.90]; p=0.005); increased with last use of tibolone (1.79 [1.43-2.25]; p<0.0001) and oestrogen only (1.45 [1.02-2.06]; p=0.04); and not significantly altered with last use of cyclic combined preparations (1.05 [0.91-1.22]; p=0.5). A woman's body-mass index significantly affected these associations, such that the adverse effects of tibolone and oestrogen-only HRT were greatest in non-obese women, and the beneficial effects of combined HRT were greatest in obese women.

INTERPRETATION

Oestrogens and tibolone increase the risk of endometrial cancer. Progestagens counteract the adverse effect of oestrogens on the endometrium, the effect being greater the more days every month that they are added to oestrogen and the more obese that women are. However, combined oestrogen-progestagen HRT causes a greater increase in breast cancer than the other therapies do. Thus, when endometrial and breast cancers are added together, there is a greater increase in total cancer incidence with use of combined HRT, both continuous and cyclic, than with use of the other therapies.

Role of progestins in contraception

Progestins have been used for contraception for more than 30 years. The main goal was to develop a contraceptive method devoid of the metabolic or clinical side-effects associated with the use of estrogens. The development of new contraceptive methods and formulations is time-consuming and requires devotion, belief, and also strong economical basis. As a result of this endeavor new methods have been developed: oral progestins, implants, injectables, intrauterine hormonal systems, and vaginal rings. Progestin-only contraceptives may be preferable in some situations, which have absolute or relative contraindications to estrogen, side-effects to estrogen containing hormonal contraception, lactation, and comfort and feasibility of formulations for long-term use. At present, emergency contraception is also performed with progestin.

Steroid hormones for contraception in men: systematic review of randomized controlled trials

Male hormonal contraception has been an elusive goal. Administration of sex steroids to men can shut off sperm production through effects on the pituitary and hypothalamus. However, this approach also decreases production of testosterone, so an "add-back" therapy is needed. We conducted a systematic review of all randomized controlled trials of male hormonal contraception and azoospermia. Few significant differences emerged from these trials. Levonorgestrel implants combined with injectable testosterone enanthate (100 mg im) were significantly more effective than was levonorgestrel 125 microg po daily combined with testosterone patches [10 mg/d; odds ratio (OR) for azoospermia with the oral levonorgestrel regimen, 0.03; 95% CI, 0.00-0.29]. The addition of levonorgestrel 500 microg po daily improved the effectiveness of testosterone enanthate 100 mg im weekly by itself (OR for azoospermia with the combined regimen, 4.0; 95% CI, 1.00-15.99). Several regimens, including testosterone alone and gonadotropin-releasing hormone agonists and antagonists, had disappointing results. In conclusion, no male hormonal contraceptive is ready for clinical use. All trials published to date have been small exploratory studies. As a result, their power to detect important differences has been limited and their results have been imprecise. In addition, the definition of oligospermia has been imprecise or inconsistent in many reports. To avoid bias, future trials need to pay more attention on the methodological requirements for randomized controlled trials. Trials with adequate power would also be helpful.

Not all progestins are the same: implications for usage

Recent clinical evidence showing unexpected side-effects of progestins used in contraception and hormone replacement therapy has highlighted the importance of choice of synthetic progestin. The molecular mechanisms of action of the relatively nonspecific and most widely used synthetic progestins, medroxyprogesterone acetate and norethisterone, are discussed in the context of this recent clinical evidence. Future directions involving a more mechanism-based approach for improved therapeutics, with greater specificity and fewer side-effects, are discussed.

A clinician's review of the WHI-related literature

When the monitoring board of the Women's Health Initiative (WHI) canceled the estrogen-progestin arm of the study in July 2002, the effect was immediate and dramatic, as several million postmenopausal women with the full agreement of their physicians ceased taking combined hormone therapy. Soon thereafter the manufacturers of conjugated equine estrogens felt compelled to publicize a drastic restriction of the indications for their product. Little notice, except in the medical literature, was given to the continuation of the other treatment arms of the WHI, nor did the rather small (however significant) increases in risk of cardiovascular disease and breast cancer resulting from combined therapy receive widespread serious analysis. In this article, special attention is given to the population sampling involved in setting up the WHI, arm by arm, with full discussion of how these samplings compare with those in other studies--HERS, ERA, WEST, etc. All studies are scrutinized in terms of treatment regimens, follow-up, confounding factors, particularly statins and aspirin, and high drop-out rates in order to discover possible reasons for the results in the WHI for primary and secondary prevention of cardiovascular disease in the combined-therapy arm and slightly disappointing results for breast cancer. Each of the two main sections of the article, Cardiovascular Disease and Breast Cancer, concludes with a detailed summation of points derived from the often contrasting results of the various studies, which can be used in counseling patients.

Implanon use in Thai women above the age of 35 years

A prospective study of Implanon implant use in women older than 35 was conducted in Bangkok, Thailand. The purposes of this study were to evaluate the menstrual pattern and side effects of Implanon in 51 women followed for 6 months. Their mean age was 39.7 years. Most acceptors had completed primary school. No accidental pregnancies occurred in 6 months of use. The most common menstrual pattern in these acceptors was irregular bleeding followed by amenorrhea. The major side effect was irregular bleeding. There was no significant change in body weight, body mass index and diastolic blood pressure during the 6-month follow-up period, but systolic blood pressure declined. Implanon implant use is a safe and effective contraceptive method and should become another choice for contraception in women aged above 35 years who have contraindications for oral contraceptive use.

Impact of progestagens on activated protein C (APC) resistance among users of oral contraceptives

Oral contraceptive (OC) use is associated with an increased risk of venous thromboembolism. Previous data reported higher thrombotic risk in women using third-generation combined OC than in those using second generation OC. The difference could be explained by differential effects of progestagens on plasma sensitivity to activated protein C (APC). The main purpose of this cross-sectional study was to assess the influence of a progestagen-only OC (chlormadinone acetate) as well as the effect of several combined OC with different progestagen components on APC resistance. The effect of APC on endogenous thrombin potential (ETP) was investigated in the plasma of healthy women using either combined OC (n=82) or progestagen-only OC (n=28), and in non-users (n=64). Carriers of factor V Leiden were excluded. Compared with non-users, there was no significant change in APC resistance in women using progestagen-only OC. Women who used combined OC were less sensitive to APC than non-users (P < 0.001) and the difference was significantly more pronounced in women using third-generation OC (n=41) than in those who used second-generation OC containing levonorgestrel (n=22) (P < 0.05). Compared with OC containing levonorgestrel, use of norethisterone-containing OC (n = 9) was associated with an increased resistance to APC (P < 0.05). Women who used cyproterone-containing OC (n = 10) were less sensitive to APC than those using third-generation OC (P < 0.05) or second-generation OC containing levonorgestrel (P < 0.05). Protein S, factor II and FVIII levels explained in part the OC-related changes in APC sensitivity variations. ETP-based APC resistance may contribute to explain why different brands of OC can be associated with different levels of thrombogenicity.

Efficacy and safety of a low-dose 24-day combined oral contraceptive containing 20 μg ethinylestradiol and 3 mg drospirenone

The aim of this open-label, multicenter, noncomparative study was to determine the efficacy, safety and bleeding profile of a new low-dose, monophasic combined oral contraceptive containing 20 micrograms ethinylestradiol and 3 mg drospirenone administered daily for 24 days followed by a 4-day hormone-free interval. Contraceptive efficacy was analyzed for 1018 women completing 11,140 treatment cycles. Eleven pregnancies occurred, giving a Pearl Index (PI) of 1.29 (upper limit of the 95% confidence interval [CI], 2.30); of these pregnancies, five were considered due to method failure, giving an adjusted PI of 0.72 (upper limit of the 95% CI, 1.69). A total of 7 (0.7%) women discontinued study medication because of irregular bleeding, suggesting a favorable bleeding profile. Overall, the treatment was well tolerated with an excellent safety profile. The majority of women (86%) stated that they were satisfied or very satisfied with the treatment and over 70% of women would have continued with the study medication.

Should Progestins Be Blamed for the Failure of Hormone Replacement Therapy to Reduce Cardiovascular Events in Randomized Controlled Trials?

Many observational studies and experimental and animal studies have demonstrated that estrogen replacement therapy (ERT) or hormone replacement therapy (HRT) (estrogen plus progestin) significantly reduces the risk of coronary heart disease. Nonetheless, recent randomized controlled trials demonstrated some trends toward an increased risk of cardiovascular events rather than a reduction of risk. Recently, both the HRT and ERT arms of the Women’s Health Initiative (WHI) study were terminated early because of an increased/no incidence of invasive breast cancer, increased incidence of stroke, and increased trend/no protective effects of cardiovascular disease. We discuss the controversial effects of HRT and ERT on cardiovascular system and provide a hypothesis that the failure of HRT and ERT in reducing the risk of cardiovascular events in postmenopausal women might be because of the stage of their atherosclerosis at the time of initiation of HRT or ERT.

Hormone Replacement Therapy and Endometrial Cancer

Postmenopausal hormone replacement therapy (HRT) using unopposed estrogens significantly increases endometrial cancer risk and should not be used in non-hysterectomized women. Even low-potency estrogens (oral estriol) or low-dose unopposed estrogens significantly enhance the risk to develop endometrial cancer. This risk is markedly reduced, when in addition to estrogens, progestins are administered for at least 10 days (better 14 days) per month. In some studies, a normalization of endometrial cancer risk to that of women receiving no HRT was only found when a continuous combined estrogen/progestin replacement was used. The use of progestins for less than 10 days per month and long-cycle regimens, where a progestin is added only every 3 months cannot be recommended. For women needing HRT, estrogen dose should be selected as low as possible and reassessment of the need of HRT should be performed annually.

Spontaneous snapping of an Implanon in two halves in situ

A 30-year-old woman presented at our family planning clinic for Implanon removal and reinsertion. At the time of presentation the patient's weight was 148 kg. The Implanon was fitted in July 2000 (i.e. 35 months previously) when her weight was 138.5 kg. The patient was very happy with the contraceptive method. She was aware that her Implanon had snapped in half about 2 months ago. There was no aggravating factor such as weightlifting associated with this incidence.

Continuous use of an oral contraceptive for endometriosis-associated recurrent dysmenorrhea that does not respond to a cyclic pill regimen

OBJECTIVE

To ascertain whether long-term reduction of pain is obtained by continuous administration of an oral contraceptive (OC) in women with endometriosis-associated recurrent dysmenorrhea that does not respond to cyclic OC use.

DESIGN

Prospective, therapeutic, self-controlled clinical trial.

SETTING

A tertiary care and referral center for patients with endometriosis.

PATIENT(S)

Fifty women who underwent surgery for endometriosis in the previous year and experienced recurrent dysmenorrhea despite cyclic OC use.

INTERVENTION(S)

Continuous use of an OC containing ethinyl estradiol (0.02 mg) and desogestrel (0.15 mg) for 2 years.

MAIN OUTCOME MEASURE(S)

Dysmenorrhea variation during cyclic and continuous OC use, evaluated with a 100-mm visual analog scale and a 0- to 3-point verbal rating scale, and degree of satisfaction with continuous OC treatment.

RESULT(S)

In the study period, amenorrhea, spotting, and breakthrough bleeding were reported by 19 (38%), 18 (36%), and 13 (26%) women. The mean +/- SD number of >7-day bleeding episodes with consequent 7-day OC suspension was 5.5 +/- 2.1. The mean +/- SD dysmenorrhea visual analog scale and verbal rating scale scores were 75 +/- 13 and 2.4 +/- 0.5 at baseline and 31 +/- 17 and 0.7 +/- 0.6 at 2-year follow-up, respectively. Moderate or severe side effects were reported by 7/50 (14%) women. At final evaluation, 13 (26%) women were very satisfied, 27 (54%) were satisfied, 1 (2%) was uncertain, 8 (16%) were dissatisfied, and 1 (2%) was very dissatisfied.

CONCLUSION(S)

Long-term continuous OC use can be proposed to women with symptomatic endometriosis and menstruation-related pain symptoms.

Estrogen plus progestin and the risk of coronary heart disease

BACKGROUND

Recent randomized clinical trials have suggested that estrogen plus progestin does not confer cardiac protection and may increase the risk of coronary heart disease (CHD). In this report, we provide the final results with regard to estrogen plus progestin and CHD from the Women's Health Initiative (WHI).

METHODS

The WHI included a randomized primary-prevention trial of estrogen plus progestin in 16,608 postmenopausal women who were 50 to 79 years of age at base line. Participants were randomly assigned to receive conjugated equine estrogens (0.625 mg per day) plus medroxyprogesterone acetate (2.5 mg per day) or placebo. The primary efficacy outcome of the trial was CHD (nonfatal myocardial infarction or death due to CHD).

RESULTS

After a mean follow-up of 5.2 years (planned duration, 8.5 years), the data and safety monitoring board recommended terminating the estrogen-plus-progestin trial because the overall risks exceeded the benefits. Combined hormone therapy was associated with a hazard ratio for CHD of 1.24 (nominal 95 percent confidence interval, 1.00 to 1.54; 95 percent confidence interval after adjustment for sequential monitoring, 0.97 to 1.60). The elevation in risk was most apparent at one year (hazard ratio, 1.81 [95 percent confidence interval, 1.09 to 3.01]). Although higher base-line levels of low-density lipoprotein cholesterol were associated with an excess risk of CHD among women who received hormone therapy, higher base-line levels of C-reactive protein, other biomarkers, and other clinical characteristics did not significantly modify the treatment-related risk of CHD.

CONCLUSIONS

Estrogen plus progestin does not confer cardiac protection and may increase the risk of CHD among generally healthy postmenopausal women, especially during the first year after the initiation of hormone use. This treatment should not be prescribed for the prevention of cardiovascular disease.

Risks and benefits, advantages and disadvantages of levonorgestrel-releasing contraceptive implants

Levonorgestrel-releasing implants are long acting contraceptives, approved for 5 years of continuous use. Two marketed systems, the six capsule Norplant use of tradenames is for product identification purposes only and does not imply endorsement. and the two rod Jadelle, have essentially equal rates of drug release, pregnancy and adverse events over 5 years of use. Randomised clinical trials and controlled cohort observations indicate that for the first 3 years, when pregnancy rates are at or almost zero, no other contraceptive system is more effective, although etonogestrel implants provide equal effectiveness. Annual pregnancy rates rise in the fifth year of continuous use but remain below 1 per 100 women. Annual pregnancy rates of Norplant users remain below 1 per 100 throughout 7 years of continuous use. Levonorgestrel implants provide low progestogen doses; 40-50 microg/day at 1 year of use, decreasing to 25-30 microg/day in the fifth year. Serum levels of levonorgestrel at 5 years are 60-65% of those levels measured at 1 month of use. Adverse effects with levonorgestrel implants are similar to those observed with progestogen only and combined oral contraceptives. Risks of ectopic pregnancy, other pregnancy complications and pelvic inflammatory disease are reduced in comparison with those of women using copper or non-medicated intrauterine devices. Risks of developing gallbladder disease and hypertension or borderline hypertension, although small, are about 1.5 and 1.8 times greater, respectively, in women using levonorgestrel implants than in women not using hormonal contraception. Other serious diseases have not been found to occur significantly more frequently in levonorgestrel implant users than in women not using hormonal contraception. The great majority of levonorgestrel implant users experience menstrual problems, but serious bleeding problems are not more frequent than in controls. Other health problems reported more frequently by levonogestrel implant users than by women not using hormonal contraception in a study of 16000 women included skin conditions, headache, upper limb neuropathies, dizziness, nervousness, malaise, minor visual disturbances, respiratory conditions, arthropathies, weight change, anxiety and non-clinical depression. Clinical depression is not more frequent in women using implants compared with those not using hormonal contraception (i.e. using intrauterine devices, sterilisation). Removal problems occur less frequently with Jadelle than with Norplant. The mean removal time for Jadelle is half that of Norplant. Levonorgestrel implants in nationally representative scientific samples, in randomised trials, and in controlled cohort studies have continuation rates as high as or higher than any other reversible contraceptive over a duration of 5 years. This would imply that the satisfaction women derive from the contraceptive effectiveness of levonorgestrel implants greatly outweighs the dissatisfaction that may accompany menstrual disturbances and other adverse effects associated with implants.

The benefit of oestrogens and progestogens in postnatal depression

Postnatal depression, with a prevalence of at least 10%, is a common complication of the puerperium. The aetiology is unclear, specific diagnostic criteria cannot be drawn and the treatment options are limited. As hormones are thought to contribute to its pathophysiology, the supplementation with either progesterone or oestrogen might be of prophylactic and/or therapeutic value in postnatal depression. Research into hormonal prophylaxis and treatment of postnatal depression (PND) is limited. This review article is aimed at exploring the evidence available regarding the use of oestrogen and progesterone in postnatal depression. A search of electronic databases Medline, Psychinfo, Embase and published books from 1970 to 2002 was carried out. The search strategy was limited to the English language. Of 193 articles, 30 were chosen and all 30 copies were identified and analysed critically. Prophylactic and treatment value were separately analysed for both oestrogen and progesterone. Some uncontrolled studies by Dalton (1982, 1985) report the benefit of progesterone in preventing postnatal depression. The value of oestrogen in preventing and treating this disorder is suggested by some articles but the methodological shortcomings in these studies make the study results unreliable. In addition, the use of oestrogen in the postnatal period may have significant side effects. Use of synthetic progesterone is associated with depression in the postnatal period and should be used with caution. Oestrogen therapy may be of modest value in severe postnatal depression.