BACKGROUND: Cancer is one of the main public health issues in the world. Breast cancer is one of the most common types of cancer among women. It is also the second cause of mortality in women. The association between the use of oral contraceptive pills and breast cancer is controversial and a main issue in public health. Some findings have shown that taking these pills does not have a significant effect in increasing the risk of breast cancer, while others have confirmed the carcinogenic effect of these products. These contradictory findings necessitated this meta-analysis, through of all correlated studies in Iran. METHODS: All published studies were considered from June 2000 until June 2015, using reliable Latin databases like PubMed, Google Scholar, Google search, Scopus, and Science Direct, and Persian database like SID, Irandoc, IranMedex, and Magiran. Finally, 26 papers were selected: 24 studies were case control while two were population based studies. A total of 26 papers with 46,260 participants were assessed since 2001. RESULTS: Overall estimate of OR for the effect of oral contraceptive pills on breast cancer is 1.521 (CI = 1.25–1.85), which shows that the intervention group had more chance (52%) compared to the control group (P = 0.001). Using these pills increased the risk of breast cancer up to 1.52 times. CONCLUSIONS: Because of directly increasing levels of estrogen and the role of estrogen in gaining weight indirectly, oral contraceptive pills can stimulate the occurrence of breast cancer. More studies should be conducted for controlling the period of pill use.
Breast Neoplasms* ; Breast* ; Case-Control Studies ; Estrogens ; Female ; Humans ; Iran ; Mortality ; Public Health ; Sudden Infant Death

Breast cancer is one of the most common causes of death all over the world. Therapeutic options applied to the patients include surgery, chemotherapy, and radiotherapy.However, far advanced disease often leads to chemoresistance and toxicity. Innovative therapies are needed to address these challenges. Melatonin has the potential to prevent and treat cancer, as it has been revealed in numerous clinical studies. Melatonin is a nontoxic agent that is mostly produced in the pineal gland, inducing various mechanisms of action such as the induction of apoptosis, antiangiogenic, antiproliferative, and metastasis-inhibitory effects. Therefore, melatonin increases therapeutic sensitivity when combined with conventional medication in breast cancer. Melatonin (3-20 mg/day) may reduce breast cancer cell growth in preclinical studies and enhance chemotherapy efficacy. Small human trials suggest potential benefits, but larger studies are needed. Higher doses (≥20 mg/day) are sometimes used alongside chemotherapy. This manuscript reviews research that has demonstrated the antitumor properties of melatonin, thereby focusing on its actions on angiogenesis, apoptosis, metastasis, and antiproliferative properties. We also discuss recent advances in the understanding of the actions of melatonin on epigenetic mechanisms (especially DNA methylation) and telomere length. The data in this review were obtained from journal articles up to May 2024.Regarding the study, Google Scholar and ScienceDirect were used as engines to search for open access. We searched the ISI, Pubmed and Scopus as valid external databases, and as internal databases, ISC and Iran medex. By finding mean keywords such as ‘breast cancer’, ‘estrogen’, ‘melatonin’, ‘cell death’, ‘cell proliferation’, ‘telomerase’ and ‘DNA methylation’, we reached to the formula with maximum collectivity in searching, then equivalent terms were found by Mesh database. The review also covers recent clinical investigations of melatonin in breast cancer.

Breast cancer is one of the most common causes of death all over the world. Therapeutic options applied to the patients include surgery, chemotherapy, and radiotherapy.However, far advanced disease often leads to chemoresistance and toxicity. Innovative therapies are needed to address these challenges. Melatonin has the potential to prevent and treat cancer, as it has been revealed in numerous clinical studies. Melatonin is a nontoxic agent that is mostly produced in the pineal gland, inducing various mechanisms of action such as the induction of apoptosis, antiangiogenic, antiproliferative, and metastasis-inhibitory effects. Therefore, melatonin increases therapeutic sensitivity when combined with conventional medication in breast cancer. Melatonin (3-20 mg/day) may reduce breast cancer cell growth in preclinical studies and enhance chemotherapy efficacy. Small human trials suggest potential benefits, but larger studies are needed. Higher doses (≥20 mg/day) are sometimes used alongside chemotherapy. This manuscript reviews research that has demonstrated the antitumor properties of melatonin, thereby focusing on its actions on angiogenesis, apoptosis, metastasis, and antiproliferative properties. We also discuss recent advances in the understanding of the actions of melatonin on epigenetic mechanisms (especially DNA methylation) and telomere length. The data in this review were obtained from journal articles up to May 2024.Regarding the study, Google Scholar and ScienceDirect were used as engines to search for open access. We searched the ISI, Pubmed and Scopus as valid external databases, and as internal databases, ISC and Iran medex. By finding mean keywords such as ‘breast cancer’, ‘estrogen’, ‘melatonin’, ‘cell death’, ‘cell proliferation’, ‘telomerase’ and ‘DNA methylation’, we reached to the formula with maximum collectivity in searching, then equivalent terms were found by Mesh database. The review also covers recent clinical investigations of melatonin in breast cancer.

Breast cancer is one of the most common causes of death all over the world. Therapeutic options applied to the patients include surgery, chemotherapy, and radiotherapy.However, far advanced disease often leads to chemoresistance and toxicity. Innovative therapies are needed to address these challenges. Melatonin has the potential to prevent and treat cancer, as it has been revealed in numerous clinical studies. Melatonin is a nontoxic agent that is mostly produced in the pineal gland, inducing various mechanisms of action such as the induction of apoptosis, antiangiogenic, antiproliferative, and metastasis-inhibitory effects. Therefore, melatonin increases therapeutic sensitivity when combined with conventional medication in breast cancer. Melatonin (3-20 mg/day) may reduce breast cancer cell growth in preclinical studies and enhance chemotherapy efficacy. Small human trials suggest potential benefits, but larger studies are needed. Higher doses (≥20 mg/day) are sometimes used alongside chemotherapy. This manuscript reviews research that has demonstrated the antitumor properties of melatonin, thereby focusing on its actions on angiogenesis, apoptosis, metastasis, and antiproliferative properties. We also discuss recent advances in the understanding of the actions of melatonin on epigenetic mechanisms (especially DNA methylation) and telomere length. The data in this review were obtained from journal articles up to May 2024.Regarding the study, Google Scholar and ScienceDirect were used as engines to search for open access. We searched the ISI, Pubmed and Scopus as valid external databases, and as internal databases, ISC and Iran medex. By finding mean keywords such as ‘breast cancer’, ‘estrogen’, ‘melatonin’, ‘cell death’, ‘cell proliferation’, ‘telomerase’ and ‘DNA methylation’, we reached to the formula with maximum collectivity in searching, then equivalent terms were found by Mesh database. The review also covers recent clinical investigations of melatonin in breast cancer.