Effets paradoxaux de la grossesse sur le cancer du sein

Sociodemographic and Reproductive Risk Factors for Breast Cancer: A Case-Control Study in the Setif Province, Northern Algeria

Background:

The age-standardized rate of breast cancer (BC) increased nearly nine-fold in the last 30 years in Setif, Algeria. A case-control study was carried out to investigate the role of sociodemographic characteristics and reproductive factors in the etiology of BC in this young Arab/Berber population of Setif.

Methods:

Cases were 612 women with incident BC admitted to major teaching and general hospitals of Setif during 2012–2017. Controls were 615 women admitted for acute, non-neoplastic conditions to the same hospital network of cases. Information was elicited using a standardized questionnaire. Odds ratios (ORs) and 95% confidence intervals (CIs) were computed after allowance for age and education.

Results:

Significant associations with BC risk emerged for family history of BC (OR= 4.15 for yes vs. no; 95%CI: 2.22-7.77), for the generation of oral contraceptive used (OR=1.57 for II-generation vs. III-generation; 95%CI:1.01-2.44), and education (OR=0.63 for >11 years vs. no schooling; 95%CI: 0.46-0.86). Conversely, parity and body mass index were not associated with BC risk, whereas a late age at menarche was linked with a non statistically significant BC risk (OR=1.20 for >15 vs. <13 years; 95%CI:0.86-1.66). These results were consistent in strata of menopausal status.

Conclusion(s):

Some of the expected risk factors (e.g., low education levels and type of oral contraceptives) were associated with elevated BC risks also in Setif, and these findings offer further support to primary preventive efforts already carried on in Algeria. Conversely, no association emerged for other well established risk factors (e.g., body mass index).

[Does fertility treatment increase the risk of breast cancer? Current knowledge and meta-analysis]

OBJECTIVE

The objective of this review was to assess the level of risk of breast cancer for women exposed to ovulation-inducing therapy (OIT).

METHODS

The 25 selected studies were extracted from the PUBMED database from January 2000 until March 2016 with the following key-words: "fertility agents", "infertility treatments", "clomiphene citrate", "buserelin", "ovarian stimulation", "assisted reproductive technology" and "breast cancer". Our meta-analysis was performed using Review Manager software, Cochrane Collaboration, 2014. The results were calculated by type of OIT, as well as globally.

RESULTS

The analysis of these published epidemiological studies confirms that exposition to OIT is not a breast cancer risk factor, but the results are contradictory. Two studies have shown a significantly increased risk of breast cancer in a population of infertile women, while two others have found a significant decrease of this risk. The twenty others did not show any impact of IOT over this risk. Our meta-analysis of 20 selected studies has not identified a significant association between exposition to OIT and breast cancer risk (relative risk=0,96; IC 95: (0,81-1,14) for cohort studies and odds ratio=0,94; IC 95% (0,81-1,10) for case-control studies).

CONCLUSION

Exposition to OIT is not an identified risk factor for breast cancer. A message reassuring about a possible risk of OIT-related breast cancer should be given to these women. Exposition to OIT is therefore not an indication of increased breast surveillance.

[Infertility and breast cancer: Is there a link? Updated review of the literature and meta-analysis]

The objective of this review was to assess the level of risk of breast cancer of patients consulting for infertility.

METHODS

Studies of cohorts and case-control were extracted from the Pubmed database from January 2000 until May 2015 through the following keywords: "infertility"; "endometriosis"; "polycystic ovary syndrome"; "breast cancer", "cancer risk". Eleven publications were finally selected after exclusion of publications dealing with infertility after breast cancer. Our meta-analysis, involving 10 of these publications, was performed using Review Manager software, Cochrane Collaboration, 2014. The results were calculated by etiology of infertility, polycystic ovary syndrome (PCOS) and endometriosis, as well as globally.

RESULTS

The analysis of these published epidemiological studies confirms that infertility is not a breast cancer risk factor, but the results are contradictory. Three studies have shown a significantly increased risk of breast cancer in a population of infertile women, while 7 others have not found this risk. These contradictions are due to the heterogeneity of the studies, the included populations, the follow-up periods and confounding factors. Our meta-analysis of the selected studies has not identified a significant association between infertility and breast cancer risk (1.05; 95% CI [0.96-1.16]). A subgroup analysis on endometriosis and PCOS showed no significant association either, with an OR of 1.02 (95% CI [0.87-1.19]) and 1.19 (95% CI [0.93-1.51]), respectively.

CONCLUSION

Infertility is not an identified risk factor for breast cancer. A message reassuring about a possible risk of infertility-related breast cancer should be given to these patients. Infertility is therefore not an indication of increased breast surveillance.