CME: Childhood Cancer: Potential Late Effects

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The Reduction in Circulating Melatonin Level May Contribute to the Pathogenesis of Ovarian Cancer: A Retrospective Study

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 Abstract
Ovarian cancer is the third most common gynaecological malignancy. Changes in circadian rhythms such as bright light exposure may affect female reproductive physiology. Night shift work is associated with higher risks of developing gynaecological cancers. In addition, the season of birth is also suggested as an important environmental risk factor for developing gynaecological cancers. Melatonin may play an important role in this association as a marker of circadian rhythms. Serum from 96 women with ovarian cancer and 40 healthy women were collected and the level of melatonin was measured. In addition 277 women with ovarian cancer and 1076 controls were retrospectively collected for season of birth analysis over seven years. The serum levels of melatonin were significantly lower in women with ovarian cancer compared with healthy women (p<0.05). However there was no difference in melatonin levels in perimenopausal and postmenopausal patients. In addition, there is no statistically significant difference in seasonal distribution of birth between ovarian cancer patients and the control group. The melatonin levels in ovarian cancer patients and controls were not associated with the season of birth. Our results demonstrate the lower serum levels of melatonin in ovarian cancer patients which may contribute to the pathogenesis of ovarian cancer. The incidence of ovarian cancer was not associated with the season of birth. The serum levels of melatonin do not appear to be associated with season of birth in ovarian cancer patients.

Introduction

Ovarian cancer is the third most common gynaecological malignancy and the leading cause of death in gynaecological cancers globally and the incidence has been increasing in the last decade [1]. Although the pathogenesis of the ovarian cancer is unclear, studies have suggested that changes in circadian rhythms such as bright light exposure may affect female reproductive physiology [2]. Night shift work is associated with higher risks of developing breast [3-5] and endometrial cancer [6]. Other studies also suggested that the season of birth may be an important environmental risk factor for developing endometrial cancer [7]. However, the mechanism of this association and whether season of birth is also associated with developing ovarian cancer remain unknown.
One of the speculations for this association is the reduction in production of melatonin by pineal glands. Melatonin a marker of circadian rhythms is an endogenously-produced lipid soluble hormone whose level changes with circadian rhythm. It has been proposed that melatonin is synthesized in mitochondria at high levels [8] and has multifaceted functions, including direct free radical scavenging. In addition to pineal gland, melatonin is also produced by the ovaries, regulating the function of the ovaries [9, 10]......

 In conclusion, we demonstrate a reduction of melatonin levels in women with ovarian cancer at diagnosis. There is no association between the incidence of ovarian cancer and season of birth, and melatonin level in women with ovarian cancer at diagnosis is not subject to season of birth. Future prospective studies are needed to confirm our findings in this study.

The Ultimate Guide To Eating For Cancer Patients – Part 2

Part 2 | CancerDocs

 Michel Choueiri

Michel completed his Oncology training at the University of California at San Diego and specialized in cancers of the kidneys, prostate and testicular cancer at the MD Anderson Cancer Center. With the constant changes in diagnostic tests and treatment options, he believes every patient should have access to the highest level of care.

The incidence of leukaemia in women with BRCA1 and BRCA2

Abstract
 The incidence of leukaemia in women with BRCA1 and BRCA2 mutations: an International Prospective Cohort Study

Background:

Germline mutations in BRCA1 and BRCA2 increase the susceptibility to develop breast and ovarian cancers as well as increase the risk of some other cancers. Primary objective was to estimate the risk of leukaemia in BRCA1 and BRCA2 mutation carriers.

Methods:

We followed 7243 women with a BRCA1 or a BRCA2 mutation for incident cases of leukaemia. We used the standardised incidence ratio (SIR) to estimate the relative risk of leukaemia, according to mutation and history of breast cancer.

Results:

We identified five incident cases of leukaemia (two BRCA1, three BRCA2). All five women had a prior history of breast cancer and four had received chemotherapy. The mean time from breast cancer diagnosis to the development of leukaemia was 10.2 years (range 3–18 years). The SIR for BRCA1 carriers was 0.66 and the SIR for BRCA2 carriers was 2.42. The SIR was significantly higher than expected for women with a BRCA2 mutation and breast cancer, in particular for women who received chemotherapy).

Conclusions:

We observed an increased risk of leukaemia in women with a BRCA2 mutation who receive chemotherapy for breast cancer.