Time trend analysis of breast cancer in Iran and its six topographical regions: a population-based study

Breast cancer is the most common cancer among women, and in 2002 it was expected that 636,000 new cases would occur in developed countries and 514,000 in developing countries. Although the incidence rate of this cancer in Asian countries is lower than in Western countries, whereas the incidence trend increasing rapidly in Asia. Using the data from the Cancer Registry System, this study was carried out to investigate the incidence trend during 2000-2005 in Iran and its six geographical areas. The incidence rates were standardized according to age-sex groups by Excel directly and confidence intervals is calculated for the point estimations by Stata11. The trends were analyzed separately based on gender, age groups for different provinces by Poisson regression in Stata11. The age standardized incidence rate in 2000 was 0.1 and 3.4 per 100,000 in males and females, respectively, reaching 0.5 and 16.7 per 100,000 in 2005. The incidence trends in all geographical areas of the country were increased despite the difference in the slopes. The sex ratio of male to female was 31.6 and the mean age of the patients was 49.4 (±12.6) years. The incidence of breast cancer in Iran was lower than the European and Asian countries but the trend is in rising. Although this increase is due to the increase in the prevalence of risk factors among Iranian population. Improvement in the coverage of the cancer registry system as well as the screening programs are important factors for these changes.

The Beginning of a Decline in Breast Cancer Incidence in Italy?

The incidence of invasive breast cancer in Turin, Italy, showed a statistically significant decrease during 1999–2003 overall (estimated annual percent change -2.6; 95% CL -8.52; -0.78) and in women aged over 50, similar to the recently documented trend in American data. This represents the first demonstration of a decline in breast cancer incidence in the early years of this decade outside the United States. In our population, the drop in the usage of hormone replacement therapy which occurred after 2002 is unlikely to be at the origin of this declining incidence trend, which is largely explained by a screening effect. This observation may be relevant to other geographical areas where organized or spontaneous screening reached a plateau after an increase in the preceding years.

Trends in detection of invasive cancer and ductal carcinoma in situ at biennial screening mammography in Spain: a retrospective cohort study

BACKGROUND

Breast cancer incidence has decreased in the last decade, while the incidence of ductal carcinoma in situ (DCIS) has increased substantially in the western world. The phenomenon has been attributed to the widespread adaption of screening mammography. The aim of the study was to evaluate the temporal trends in the rates of screen detected invasive cancers and DCIS, and to compare the observed trends with respect to hormone replacement therapy (HRT) use along the same study period.

METHODS

Retrospective cohort study of 1,564,080 women aged 45-69 years who underwent 4,705,681 screening mammograms from 1992 to 2006. Age-adjusted rates of screen detected invasive cancer, DCIS, and HRT use were calculated for first and subsequent screenings. Poisson regression was used to evaluate the existence of a change-point in trend, and to estimate the adjusted trends in screen detected invasive breast cancer and DCIS over the study period.

RESULTS

The rates of screen detected invasive cancer per 100.000 screened women were 394.0 at first screening, and 229.9 at subsequent screen. The rates of screen detected DCIS per 100.000 screened women were 66.8 at first screen and 43.9 at subsequent screens. No evidence of a change point in trend in the rates of DCIS and invasive cancers over the study period were found. Screen detected DCIS increased at a steady 2.5% per year (95% CI: 1.3; 3.8), while invasive cancers were stable.

CONCLUSION

Despite the observed decrease in breast cancer incidence in the population, the rates of screen detected invasive cancer remained stable during the study period. The proportion of DCIS among screen detected breast malignancies increased from 13% to 17% throughout the study period. The rates of screen detected invasive cancer and DCIS were independent of the decreasing trend in HRT use observed among screened women after 2002.

Systematic review about breast cancer incidence in relation to hormone replacement therapy use

BACKGROUND

Several studies report a decrease in breast cancer incidence subsequent to the decrease in hormone replacement therapy (HRT) use. But its magnitude and the time-lag may vary between countries. This may reflect differences in populations, previous type and prevalence of HRT use and breast cancer screening.

AIM

To review systematically studies assessing the relation between breast cancer incidence and change of HRT use.

MATERIAL AND METHOD

Descriptive analysis of the methodology of the studies including design limitations and presence of confounding factors, data sources for breast cancer and HRT and regimens of HRT used.

RESULTS AND DISCUSSION

Eighteen articles were selected. Most studies were ecological and confounding factors such as mammography screening and changes in reproductive and lifestyle habits could not be excluded. Sources of data on breast cancer and HRT were heterogeneous and only few data on HRT regimens used were available. Most studies concluded that the decrease in HRT use during the last decade was probably associated with a decrease in breast cancer incidence, especially for women aged 50 years or more.

CONCLUSIONS

Data, mostly from epidemiological studies, suggest that the decrease in breast cancer incidence can be partly attributed to the drop in HRT use. Nevertheless, available studies are hampered by a number of limitations and it remains difficult to evaluate the exact impact of the drop in HRT use on the decrease in breast cancer incidence. Especially, the studies are seldom based on detailed individual data and do not provide information on regimens used, type of cancers and possible confounding factors.

Trends in incidence of breast cancer among women under 40 in seven European countries: a GRELL cooperative study

Young women are not usually screened for breast cancer (BC). The trends in incidence in this population may better reflect changes in risk factors. However, studies on this subject are scarce and heterogeneous. The aim of this study was to describe the trends in incidence of BC in women under 40 from 1990 to 2008, using pooled European data. Thirty-seven European population-based cancer registries from Belgium, Bulgaria, France, Italy, Portugal, Spain and Switzerland participated in this study. World age-standardized incidence rates were first analyzed graphically and then using a Poisson regression model, in order to estimate average annual percent changes (AAPCs). The overall incidence rate of BC in the area covered increased linearly during the study period by 1.19% (0.93; 1.46) on average per year. This increase varied between countries from 0.20% (-0.53; 0.64) in Bulgaria to 2.68% (1.97; 3.40) in Portugal. In Italy, after a significant rise of 2.33% (1.14; 3.54) per year, BC incidence began decreasing in 2002 by -2.30% (-4.07; -0.50) yearly. The rise in incidence was greater for women under 35 and for ductal carcinomas. This increase can be due to a rise in risk factors and/or changes in diagnosis and surveillance practices, but we could not clearly distinguish between these two non-exclusive explanations.

Near-infrared imaging of breast cancer using optical contrast agents

Breast cancer is the most common malignancy in women worldwide and the second leading cause of cancer death. On the basis of three studies performed by our group, this article reviews the current status of optical breast imaging using extrinsic contrast agents. To date, only two contrast agents have been applied in human studies, indocyanine green (ICG) and omocianine. Both contrast media were used for absorption and fluorescence imaging. Generally speaking, malignant breast lesions exhibited higher absorption contrast as well as higher fluorescence contrast compared to benign lesions or non-diseased breast tissue. Some groups consider early enhancement characteristics helpful for differentiation between malignant and benign lesions. Late fluorescence ICG imaging - capitalizing on the extravasation of the dye through the wall of tumorous vessels - seems to be a promising technique to distinguish malignant from benign breast lesions.

Screening mammography use among current, former, and never hormone therapy users may not explain recent declines in breast cancer incidence

BACKGROUND

Screening mammography and invasive breast cancer and ductal carcinoma in situ (DCIS) rates recently declined in the United States; screening mammography declines among former hormone therapy (HT) users may be an important contributor. We longitudinally examined women and compared mammography use and cancer rates by HT use [current, former, and never users of estrogen + progestin (EPT) and estrogen only (ET)].

METHODS

We studied 163,490 unique women aged 50-79 years enrolled in Group Health (Washington State) between 1994-2009. Electronic data identified HT dispensing, mammography use and incident breast cancer diagnosis. We calculated age-adjusted screening compliance as a time-varying variable (screened-within-the-past-26 months, yes/no).

RESULTS

Before 2002, screening compliance differed significantly by HT with current EPT users having the highest rates (83%) followed by former EPT (77%), current ET (77%), former ET (72%), and never users (56%). After 2002, screening was high (∼81%) among current and former EPT and ET users and significantly increased among never users (∼62%). Invasive breast cancer rates significantly decreased over the whole study period (P(trend) ≤ 0.05) for all HT users, except EPT current users (P(trend) = 0.68); DCIS rates did not change in any group.

CONCLUSIONS

Differential screening mammography rates by HT use do not explain invasive breast cancer incidence declines. Our data suggest discontinuing HT has an immediate effect on breast cancer rates, lending support to the mechanism that cessation leads to tumor regression.

IMPACT

Studies examining the influence of a changing exposure in relation to outcomes should account for varying exposures, individuals' characteristics, as well as screening methods and frequency.

An epidemiological overview of the relationship between hormone replacement therapy and breast cancer

Large-scale randomized clinical trials and observational studies have consistently found that use of hormone replacement therapy (HRT) increases the risk of breast cancer. More recently, ecological studies have shown correlations between dramatic reductions in use of HRT in many countries, and declines in the rates of breast cancer in older women. Meta-analyses of data from the trials and observational studies show that the increase in breast cancer risk is greater for combined estrogen-progestin therapies compared with estrogen alone; that for both types of preparation, breast cancer risk increases with duration of use; and that the risks decrease relatively quickly after cessation of use. For both estrogen-only and combined therapies, the risk of breast cancer is higher if therapy is initiated close to the time of the menopause, relative to the risks in women starting HRT later. Most drug regulatory authorities currently recommend that HRT be prescribed only to fully informed women who have moderate-to-severe menopausal symptoms, for the shortest duration possible; and it is recommended that the need for therapy be reviewed at least every 6-12 months.

Is the decrease in breast cancer incidence related to a decrease in postmenopausal hormone therapy?

Following the Women's Health Initiative (WHI) publication in mid 2002, a drastic decrease in hormone therapy for postmenopausal women has been observed worldwide. Since 2007, the reported incidence in breast cancer has declined. Most authors have linked this decline to the reduction in hormone treatment. In this paper we discuss why these ecological observations are not fully convincing and focus on the importance of screening and variations in other risk factors to interpret this decline in breast cancer.

Breast cancer incidence and hormone replacement therapy in Canada

BACKGROUND

In 2002, results of the Women's Health Initiative clinical trial indicated that the long-term risks of combined estrogen and progestin hormone replacement therapy outweighed the health benefits for postmenopausal women. The resulting decline in use of hormone replacement therapy was followed by concurrent decreases in breast cancer incidence in several countries. The aim of the current study was to determine whether similar declines occurred in Canada.

METHODS

Data on prescriptions for hormone therapy were obtained from a national registry of pharmacy-filled prescriptions to confirm the reported trend in use of hormone replacement therapy among approximately 1200 women aged 50-69 years who participated in the National Population Health Survey between 1996 and 2006 and whose data were extrapolated to the Canadian female population. Age-standardized incidence rates for breast cancer were obtained from the population-based Canadian Cancer Registry for the same period, and mammography rates were obtained from the Canadian Community Health Survey. Joinpoint regression was used to examine changes in trends in the use of hormone replacement therapy and breast cancer incidence.

RESULTS

A reduced frequency of use of hormone replacement therapy was reflected in the decrease in dispensed hormone therapy prescriptions after 2002. The largest drop in use of combined hormone replacement therapy (from 12.7%, 95% confidence interval [CI] = 10.1% to 14.2%, to 4.9%, 95% CI = 3.4% to 6.8%, of all women) occurred between January 1, 2002, and December 31, 2004, among women aged 50-69 years. This drop occurred concurrently with a 9.6% decline in the incidence rate of breast cancer (from 296.3 per 100,000 women, 95% CI = 290.8 to 300.5 per 100,000 women, in 2002 to 268.0 per 100,000 women, 95% CI = 263.3 to 273.5 per 100,000 women, in 2004). Mammography rates were stable at 72% over the same period.

CONCLUSION

During the period 2002-2004, there was a link between the declines in the use of hormone replacement therapy and breast cancer incidence among Canadian women aged 50-69 years, in the absence of any change in mammography rates.

Recent trends in hormone therapy utilization and breast cancer incidence rates in the high incidence population of Marin County, California

Background

Recent declines in invasive breast cancer have been reported in the US, with many studies linking these declines to reductions in the use of combination estrogen/progestin hormone therapy (EPHT). We evaluated the changing use of postmenopausal hormone therapy, mammography screening rates, and the decline in breast cancer incidence specifically for Marin County, California, a population with historically elevated breast cancer incidence rates.

Methods

The Marin Women's Study (MWS) is a community-based, prospective cohort study launched in 2006 to monitor changes in breast cancer, breast density, and personal and biologic risk factors among women living in Marin County. The MWS enrolled 1,833 women following routine screening mammography between October 2006 and July 2007. Participants completed a self-administered questionnaire that included items regarding historical hormone therapy regimen (estrogen only, progesterone only, EPHT), age of first and last use, total years of use, and reason(s) for stopping, as well as information regarding complementary hormone use. Questionnaire items were analyzed for 1,083 non-Hispanic white participants ages 50 and over. Breast cancer incidence rates were assessed overall and by tumor histology and estrogen receptor (ER) status for the years 1990-2007 using data from the Northern California Surveillance, Epidemiology and End Results (SEER) cancer registry.

Results

Prevalence of EPHT use among non-Hispanic white women ages 50 and over declined sharply from 21.2% in 1998 to 6.7% by 2006-07. Estrogen only use declined from 26.9% in 1998 to 22.4% by 2006-07. Invasive breast cancer incidence rates declined 33.4% between 2001 and 2004, with drops most pronounced for ER+ cancers. These rate reductions corresponded to declines of about 50 cases per year, consistent with population attributable fraction estimates for EPHT-related breast cancer. Self-reported screening mammography rates did not change during this period. Use of alternative or complementary agents did not differ significantly between ever and never hormone users. Of women who reported stopping EPHT in the past 5 years, 60% cited "health risks" or "news reports" as their primary reasons for quitting.

Conclusion

A dramatic reduction in EPHT use was followed temporally by a significant reduction in invasive and ER+ breast cancer rates among women living in Marin County, California.

Disentangling the roles of mammographic screening and HRT in recent breast cancer incidence trends in italy by analyses based on calendar time and time since screening activation

The aim of the study was to evaluate the roles of screening activation and hormone replacement therapy discontinuation on the recent declining breast cancer incidence trends in Italy. We analyzed 41,358 invasive female breast cancers incident during 1991-2004 in six Italian population-based cancer registries. Overall and age-specific incidence trends were evaluated using Joinpoint analysis. In addition to calendar years, data were analyzed on a years-since-screening-activation basis. Annual percentage change of standardized rates was computed. There were statistically significant increasing trends for women 40-44 and 45-49 years that did not change after screening activation. On the contrary, for women 50-69 years old and for those 70+ years, the increasing trends flattened around 2 years after screening activation. The prevalence of hormone replacement therapy use in Italy is and was rather low. In conclusion, the recent tendency toward stabilization observed in Italy for female breast cancer incidence rates in women aged 50 years or more follows the introduction of mammographic screening.

The benefits of oestrogen following menopause: why hormone replacement therapy should be offered to postmenopausal women

Recently, two major epidemiological studies found that hormone replacement therapy (HRT) in postmenopausal women increased the risk of breast cancer. One of the studies also found that HRT increased the risk of cardiovascular disease and thrombosis. As a consequence, women were advised to cease this therapy. However, detailed analysis of these studies suggests that the conclusions may be erroneous. Other studies suggest that the timing of initiation of HRT for healthy women is critical to achieving a beneficial outcome. When begun within 5 years of menopause in healthy women, oestrogen-based HRT results in far greater benefits than adverse outcomes. There is substantial objective evidence that the benefits of HRT include: Reduced distressing symptoms of menopause. Reduced risk of osteoporotic fractures, dementia and colorectal cancer. Improved wellbeing, quality of life; improved vaginal epithelium, sexual enjoyment and bladder capacity. Improved cardiovascular system, with reduced myocardial ischaemia and cardiovascular-related death. Increased longevity. The adverse effects of HRT include: Oral HRT doubles the risk of thromboembolism. HRT promotes growth of pre-existing breast cancer.

The decline in breast cancer incidence: real or imaginary?

Breast cancer is a major global problem, with nearly 1 million cases occurring each year. Over the past several decades, the disease's incidence has risen worldwide, increasing in developing and developed countries. This rise in breast cancer incidence has been attributed to changes in lifestyle and reproductive factors and to the dissemination of population-wide mammographic screening, which facilitates diagnosis. Recently, a decline in breast cancer incidence was reported in the United States and several other developed countries, and a substantial reduction in menopausal hormone therapy use was proposed as a possible cause. However, significant controversy remains as to the timing, causes, generalizability, and longevity of this reported decline in incidence.