Serum calcium and breast cancer risk: results from a prospective cohort study of 7,847 women

Serum metabolite and metal ions profiles for breast cancer screening

Enhancing early-stage breast cancer detection requires integrating additional screening methods with current diagnostic imaging. Omics screening, using easily collectible serum samples, could serve as an initial step. Alongside biomarker identification capabilities, omics analysis allows for a comprehensive analysis of prevalent histological types-DCIS and IDC. Employing metabolomics, metallomics, and machine learning, could yield accurate screening models with valuable insights into organism responses. Serum samples of confirmed breast cancer patients were utilized to analyze metabolite and metal ion profiles, using two distinct analysis methods, proton NMR for metabolomics and ICP-OES for metallomics. The resulting responses were then subjected to discriminant analysis, progression biomarker exploration, examination of correlations between patients' metabolites and metal ions, and the impact of age and menopause status. Measured NMR spectra and metabolite relative integrals were used to achieve statistically significant discrimination through MVA between breast cancer and control groups. The analysis identified 24 metabolites and 4 metal ions crucial for discrimination. Furthermore, four metabolites were associated with disease progression. Additionally, there were important correlations and relationships between metabolite relative integrals, metal ion concentrations, and age/menopausal status subgroups. Quantified relative integrals allowed for discrimination between studied subgroups, validated with a holdout set. Feature importance and statistical analysis for metabolomics and metallomics extracted a set of common entities which in combination provides valuable insights into ongoing molecular disturbances and disease progression.

Analysis of Preoperative Predictors of Single and Multigland Primary Hyperparathyroidism

INTRODUCTION

Preoperative differentiation of single-gland (SG) versus multigland (MG) primary hyperparathyroidism (PHPT) can assist with surgical planning, treatment prognostication, and patient counseling. The aim of this study was to identify preoperative predictors of SG-PHPT.

METHODS

Retrospective analysis of 408 patients with PHPT who underwent parathyroidectomy at a tertiary referral center. Comprehensive preoperative parameters, including demographic, laboratory, clinical, and imaging results were analyzed. Univariate analysis and binary logistic regression identified preoperative predictors of SG-PHPT. Receiver operator curves were used to analyze the predictive values of existing and novel preoperative predictive models.

RESULTS

Elevated parathyroid hormone (PTH) (99.1 pg/mL in SG versus 93.0 pg/mL in MG), elevated calcium (10.8 mg/dL in SG versus 10.6 mg/dL in MG), lower phosphate levels (2.80 mg/dL in SG versus 2.95 mg/dL in MG), and positive imaging (ultrasound 75.6% in SG versus 56.5% in MG; sestamibi 70.8% in SG versus 45.5% in MG) were significantly associated with SG-PHPT. The Washington University Score (a predictive scoring system made from calcium, PTH, phosphate, ultrasound, and sestamibi) and the Washington University Index ([calcium × PTH]/phosphate) were comparable to previous scoring systems used to predict SG versus MG-PHPT.

CONCLUSIONS

The association of lower phosphate with SG-PHPT is a novel finding. Previously identified predictors of SG-PHPT, including elevated PTH and positive imaging were confirmed. The Washington University Score and Index are comparable to previously described models and can be used to help surgeons predict if a patient may have SG versus MG-PHPT.

Magnitude of parathyroid hormone elevation in primary hyperparathyroidism: Does time of day matter?

BACKGROUND

Parathyroid hormone demonstrates a circadian rhythm in nondiseased patients, but it is unclear if this diurnal variation persists in the context of primary hyperparathyroidism. We anecdotally noticed that parathyroid hormone levels drawn early on the morning of parathyroid surgery (preincision parathyroid hormone), were of lower magnitude than values obtained at later times in the day. If present, a time-of-day based variation in parathyroid hormone could have important clinical implications on intraoperative surgical decision making.

METHODS

We performed an Institutional Review Board-approved, retrospective chart review of patients undergoing parathyroidectomy for primary hyperparathyroidism between October 2019 and February 2022 at a quaternary care referral center. Demographic, laboratory, imaging, and operative parameters were extracted. Analysis was performed using mixed models for repeated measures with a first order autoregression correlation structure. Parathyroid hormone values were compared before and after hourly intervals between 6:00 A.M. and 12:00 P.M.

RESULTS

Of 418 patients, the mean age was 61 years old, 80% of patients were female, and two-thirds had single-gland disease. A total of 933 parathyroid hormone levels were included in the analysis and median parathyroid hormone was 97.3 pg/mL. Parathyroid hormone levels were noted to be significantly lower if they were drawn before 7:00 A.M. This diurnal variation persisted in patients with single-gland and advanced hyperparathyroidism but was abrogated in multi-gland and low-baseline-parathyroid hormone disease.

CONCLUSION

In patients with primary hyperparathyroidism, parathyroid hormone levels were significantly lower in the early morning hours, especially in patients with single-gland and high-baseline-parathyroid hormone hyperparathyroidism. This may have implications for intraoperative decision making when utilizing an early morning, preincision parathyroid hormone value.

Increased thyroid malignancy in patients with primary hyperparathyroidism

BACKGROUND

Multiple studies have reported the increased incidence of thyroid cancer in patients with primary hyperparathyroidism (PHPT). However, the underlying risk factors of concomitant thyroid cancer in patients with PHPT remain unknown. The primary aim of this study was to examine the records of patients with PHPT to identify characteristics that correlated with the presence of coexisting thyroid nodules, and which may have an implication for the prediction of thyroid cancer.

METHODS

Medical records of consecutive patients with PHPT (n = 318) were reviewed from January 2010 to September 2020 in two tertiary medical centers in China. Patient clinicopathological and biological data were collected and analyzed.

RESULTS

Of a total of 318 patients with PHPT, 105 (33.0%) patients had thyroid nodules and 26 (8.2%) patients were concomitant with thyroid cancer. A total of 38 thyroid nodules taken from 26 patients were pathologically assessed to be well-differentiated papillary thyroid carcinoma (PTC), with 81% being papillary thyroid microcarcinoma (PTMC). In 79% (30/38) of these cancers, thyroid nodules were considered suspicious following preoperative ultrasound. Multinomial logistic regression analysis revealed that female gender was associated with increased risk of thyroid nodules (OR = 2.13, 95% CI: 1.13-3.99, P = 0.019), while lower log-transformed parathyroid hormone levels were an independent predictor of thyroid cancer in patients with PHPT (OR = 0.50, 95% CI: 0.26-0.93, P = 0.028).

CONCLUSION

In conclusion, we observed a relatively high prevalence of thyroid cancer in our cohort of Chinese patients with PHPT. Evaluation of thyroid nodules by preoperative ultrasound may be advisable in patients with PHPT, particularly for females and patients with modestly elevated serum parathyroid hormone levels.

Phytotherapy and Nutritional Supplements on Breast Cancer

Breast cancer is the most frequent type of nonskin malignancy among women worldwide. In general, conventional cancer treatment options (i.e., surgery, radiotherapy, chemotherapy, biological therapy, and hormone therapy) are not completely effective. Recurrence and other pathologic situations are still an issue in breast cancer patients due to side effects, toxicity of drugs in normal cells, and aggressive behaviour of the tumours. From this point of view, breast cancer therapy and adjuvant methods represent a promising and challenging field for researchers. In the last few years, the use of some types of complementary medicines by women with a history of breast cancer has significantly increased such as phytotherapeutic products and nutritional supplements. Despite this, the use of such approaches in oncologic processes may be problematic and patient's health risks can arise such as interference with the efficacy of standard cancer treatment. The present review gives an overview of the most usual phytotherapeutic products and nutritional supplements with application in breast cancer patients as adjuvant approach. Regardless of the contradictory results of scientific evidence, we demonstrated the need to perform additional investigation, mainly well-designed clinical trials in order to establish correlations and allow for further validated outcomes concerning the efficacy, safety, and clinical evidence-based recommendation of these products.

Serum Calcium and Risk of Nonmedullary Thyroid Cancer in Patients with Primary Hyperparathyroidism

Background

Clinical cases of nonmedullary thyroid carcinoma (NMTC) in combination with primary hyperparathyroidism (PHPT) have been reported occasionally. However, the clinical characteristics and risk factors of concomitant NMTC in PHPT patients remain unclear. This study aimed to assess the association between PHPT and NMTC, and evaluate the clinical characteristics and risk factors of NMTC in Chinese patients with PHPT.

Material/Methods

This was a retrospective cohort analysis. We reviewed the medical records of 155 patients who underwent surgery for PHPT in two large medical centers in China between 2009 and 2014. The clinical manifestations, biochemical abnormalities, and histological characteristics of PHPT patients were analyzed.

Results

Of the 155 patients with PHPT, 58 patients (37.4%) had thyroid nodules and 12 patients (7.7%) were ill with concomitant NMTC. PHPT patients with NMTC demonstrated significantly lower preoperative serum calcium levels compared to PHPT patients with benign thyroid nodules (p<0.05). A significantly negative association between preoperative serum calcium levels and the presence of NMTC was found in PHPT patients (p<0.05). Furthermore, ROC analysis revealed that albumin-corrected serum calcium levels <2.67 mmol/L had good capacity to differentiate the PHPT patients with NMTC from those with benign thyroid nodules.

Conclusions

Compared with the reported much lower prevalence of thyroid carcinoma in the general population, our results suggest that PHPT might be a risk factor for the malignancy of thyroid nodules; a lower level of serum calcium may predict the existence of NMTC in PHPT patients with thyroid nodules.

Serum Calcium and the Risk of Breast Cancer: Findings from the Swedish AMORIS Study and a Meta-Analysis of Prospective Studies

To investigate the association between serum calcium and risk of breast cancer using a large cohort and a systematic review with meta-analysis. From the Swedish Apolipoprotein Mortality Risk (AMORIS) Study we included 229,674 women who had baseline measurements of serum total calcium and albumin. Multivariable Cox regression was used to assess the association between total and albumin-corrected calcium and breast cancer risk. For the systematic review, an electronic search of MEDLINE and EMBASE databases was performed to identify other prospective cohorts assessing the relationship between serum calcium and breast cancer risk. We pooled the results of our AMORIS cohort with other eligible studies in a meta-analysis using a random effects model. I² test was used to assess heterogeneity. In the AMORIS study, 10,863 women were diagnosed with breast cancer (mean follow-up: 19 years). We found an inverse association between total serum calcium and breast cancer when comparing the fourth quartile to the first quartile (HR: 0.94, 95% CI: 0.88–0.99, p value for trend 0.04) and similar results using albumin-corrected calcium. In the systematic review, we identified another two prospective cohorts evaluating pre-diagnostic serum total calcium and breast cancer. Combining these studies and our findings in AMORIS in a meta-analysis showed a protective effect of serum calcium against breast cancer, with a summary RR of 0.80 (95% CI: 0.66–0.97). No substantial heterogeneity was observed. Our findings in AMORIS and the meta-analysis support an inverse association between serum calcium and breast cancer risk, which warrants mechanistic investigations.

Independent and joint effects of serum 25-hydroxivitamin D and calcium on breast cancer ratio in an Iran population: A cross-sectional study

BACKGROUND

It has been suggested that Vitamin D and calcium have protective effects against breast cancer. The results about breast cancer and serum Vitamin D and calcium levels are still controversial, indefinite, and insufficient to determine the amount of nutritional needs. Thus, we investigated the association between serum 25-hydroxyvitamin D(25-OH-D) and calcium on the ratio of breast cancer at diagnosis time.

MATERIALS AND METHODS

We carried out a hospital-based cross-sectional study in a population of Iran. It comprised 57 breast cancer cases, who were newly diagnosed, and 85 controls in 2013. The serum 25-OH-D and calcium levels were measured.

RESULTS

There was not any significant association between 25-OH-D and breast cancer ratio. Odds ratio (OR) comparing the highest quartile to the lowest quartile was 1.03(95% confidence interval[CI] 0.33-3.22, P-trend 0.95). Having sufficient (>75 nmol/L) serum 25-OH-D levels compared to insufficient serum 25-OH-D levels was not associated with a significantly decreased ratio of breast cancer (OR 0.55, 95% CI 0.23-1.29, P = 0.17). Furthermore, an association between calcium and breast cancer did not get statistical significance (OR 0.51, 95% CI 0.17-1.49, P-trend 0.31). The joint effect was negative interaction.

CONCLUSION

Vitamin D and calcium do not act on decreasing ratio of breast cancer. Decreasing ratio of breast cancer in relation to serum calcium and Vitamin D level at diagnosis time needs more assessments.

Total, dietary, and supplemental calcium intake and mortality from all-causes, cardiovascular disease, and cancer: A meta-analysis of observational studies

AIMS

This systematic review and meta-analysis of observational studies was conducted to summarize the evidence on the association between calcium intake and mortality.

METHODS AND RESULTS

PubMed, Institute for Scientific Information (ISI) (Web of Science), SCOPUS, SciRUS, Google Scholar, and Excerpta Medica dataBASE (EMBASE) were searched to identify related articles published through May 2014. We found 22 articles that assessed the association between total, dietary, and supplementary intake with mortality from all-causes, cardiovascular disease (CVD), and cancer. Findings from this meta-analysis revealed no significant association between total and dietary calcium intake and mortality from all-causes, CVD, and cancer. Subgroup analysis by the duration of follow-up revealed a significant positive association between total calcium intake and CVD mortality for cohort studies with a mean follow-up duration of >10 years (relative risk (RR): 1.35; 95% confidence interval (CI): 1.09-1.68). A significant inverse association was seen between dietary calcium intake and all-cause (RR: 0.84; 95% CI: 0.70-1.00) and CVD mortality (RR: 0.88; 95% CI: 0.78-0.99) for studies with a mean follow-up duration of ≤10 years. Although supplemental calcium intake was not associated with CVD (RR: 0.95; 95% CI: 0.82-1.10) and cancer mortality (RR: 1.22; 95% CI: 0.81-1.84), it was inversely associated with the risk of all-cause mortality (RR: 0.91; 95% CI: 0.88-0.94).

CONCLUSIONS

We found a significant relationship between the total calcium intake and an increased risk of CVD mortality for studies with a long follow-up time and a significant protective association between dietary calcium intake and all-cause and CVD mortality for studies with a mean follow-up of ≤10 years. Supplemental calcium intake was associated with a decreased risk of all-cause mortality.

Analysis of serum levels of 15 trace elements in breast cancer patients in Shandong, China

Experimental and epidemiological studies suggest that serum levels of trace elements may be associated with breast cancer risk. We compared serum levels of 15 trace elements between breast cancer patients and normal controls from Shandong, China, for the first time to assess whether serum levels of trace elements were associated with breast cancer risk. Eighty-eight breast cancer patients and 84 healthy controls were enrolled in the study. A Spectraspan V direct current plasma atomic emission spectrometer was used to determine the serum levels of 15 trace elements including Zn, Mn, Al, Cd, Fe, Mg, Ca, Pb, Cu, Se, Ni, Ti, Co, Li, and Cr. Breast cancer patients had significantly higher serum levels of Cd (p = 0.000), Mg (p = 0.001), Cu (p = 0.000), Co (p = 0.006), and Li (p = 0.003) and borderline higher Cr (p = 0.052), while significantly lower Mn (p = 0.000), Al (p = 0.000), Fe (p = 0.000), and Ti (p = 0.000) compared to their matched controls. However, there were no significant differences in serum levels of Zn (p = 0.824), Ca (p = 0.711), Pb (p = 0.274), Se (p = 0.236), and Ni (p = 0.185) between the two groups. Our study showed a possible association between serum levels of trace elements and breast cancer risk in eastern China, though it warrants further investigations to confirm the association. If confirmed, modulation of trace elements may help reduce breast cancer risk.

Serum calcium level used as a prognostic predictor in patients with resectable pancreatic ductal adenocarcinoma

BACKGROUND AND OBJECTIVE

There is a relative scarcity of reports to evaluate the associations between serum calcium level and the prognosis in patients with pancreatic ductal adenocarcinoma (PDAC). The aim of this study was to determine whether serum calcium level is a significant predictor for survival in PDAC patients.

METHODS

This is a retrospective cohort study. The clinicopathological characteristics, preoperative serum calcium levels and the survival data of 114 patients who underwent surgery for PDAC between January 1, 2009 and January 31, 2012 were collected. The associations between serum calcium level and overall survival were evaluated using the multivariate Cox proportional hazards model.

RESULTS

The median age of the patients was 60 years, and 64 (56.1%) of them were male. Eighty-one cases (71.1%) were dead at the last follow up. Forty-four patients (38.6%) died within the first year after surgery. The receiver operating characteristics (ROC) curve indicated a significant result for serum calcium level in predicting one-year death after surgery [area under the curve (AUC), 0.629; 95% CI 0.527-0.730, P=0.021]. In multivariate analysis, higher serum calcium levels [hazard ratio (HR), 1.922; P=0.036], diabetes (HR, 1.820; P=0.017), histologically poorly-differentiated tumor (HR, 3.342; P=0.001) and vessel invasion (HR, 1.729; P=0.023) were independent predictors of poor prognosis. Similarly, the albumin-adjusted albumin level was also an independent prognostic factor.

CONCLUSIONS

The higher serum calcium level is associated with poor prognosis in patients with resectable PDAC and the level of serum calcium can predict death within one year after surgery.

Serum levels of vitamin D, parathyroid hormone and calcium in relation to survival following breast cancer

Purpose

Vitamin D, parathyroid hormone (PTH) and calcium in blood are correlated with each other. Previous studies have suggested vitamin D to have anti-proliferative effects on tumor cells, whereas PTH may have carcinogenic effects. A cancer disease may influence calcium levels in blood, but less is known about calcium and its potential effect on cancer risk and survival. The aim of this study was to examine pre-diagnostic levels of vitamin D (25OHD), PTH and calcium in relation to survival after breast cancer.

Methods

The Malmö Diet and Cancer Study enrolled 17,035 women between 1991 and 1996. 672 patients developed incident invasive breast cancer up until 31 December 2006. Serum samples collected at baseline were analyzed for 25OHD, PTH and calcium. All patients were followed until 31 December 2010 using the Swedish Cause of Death Registry. The analytes were divided into tertiles and the risk of death from breast cancer was analyzed using an adjusted Cox proportional hazards analysis, yielding hazard ratios with 95 % confidence intervals.

Results

Levels of 25OHD and breast cancer mortality were associated in a u-shaped manner with the highest mortality among patients in the first (2.46: 1.38–4.37) and third tertiles (1.99: 1.14–3.49), as compared to the second. An inverse relation was found between calcium levels and breast cancer mortality, with the lowest mortality in the third tertile, (0.53: 0.30–0.92) as compared to the first. There was no clear association between PTH and breast cancer mortality.

Conclusions

This study shows that pre-diagnostic 25OHD and calcium may affect survival following breast cancer.

Dietary intake of vitamin D and calcium and breast cancer risk in the European Prospective Investigation into Cancer and Nutrition

Studies assessing the effects of vitamin D or calcium intake on breast cancer risk have been inconclusive. Furthermore, few studies have evaluated them jointly. This study is the largest so far examining the association of dietary vitamin D and calcium intake with breast cancer risk in the European Prospective Investigation into Cancer and Nutrition. During a mean follow-up of 8.8 yr, 7760 incident invasive breast cancer cases were identified among 319,985 women. Multivariable Cox proportional hazards regression was used to estimate hazard ratios (HR) and 95% confidence intervals (CI) for pre- and postmenopausal breast cancer risk. Comparing the highest with the lowest quintile of vitamin D intake, HR and 95% CI were 1.07 (0.87-1.32) and 1.02 (0.90-1.16) for pre- and postmenopausal women, respectively. The corresponding HR and 95% CIs for calcium intake were 0.98 (0.80-1.19) and 0.90 (0.79-1.02), respectively. For calcium intake in postmenopausal women, the test for trend was borderline statistically significant (P(trend) = 0.05). There was no significant interaction between vitamin D and calcium intake and cancer risk (P(interaction) = 0.57 and 0.22 in pre- and postmenopausal women, respectively). In this large prospective cohort, we found no evidence for an association between dietary vitamin D or calcium intake and breast cancer risk.

Serum calcium concentration and prostate cancer risk: a multicenter study

This study sought to further evaluate the possible effects of serum calcium level on prostate cancer (PC) risk, with considering the age, body mass index (BMI), and sex steroid hormones. Using data from a prospective multicenter study, serum calcium concentration, as well as thorough demographic and medical characteristics, were determined in 194 cases with newly diagnosed, clinicopathologically confirmed PC and 317 controls, without any malignant disease, admitted to the same network of hospitals. Serum total and ionized calcium levels were categorized into tertiles. Multivariate logistic regression model was used to estimate odds ratios (OR) and corresponding 95% confidence intervals (CI) after adjustment for major potential confounders, including age, BMI, smoking, alcohol, education, occupation, marital status, family history of PC, and sex hormones level. The mean serum calcium level (±SD) in case and control groups was 9.22 (±0.46) mg/dl and 9.48 (±0.51) mg/dl, respectively (P < 0.001). After adjustment for mentioned confounders, a significant trend of decreasing risk was found for serum total calcium concentration (OR = 0.27, 95% CI = 0.12-0.59, comparing the highest with the lowest tertile) and ionized calcium (OR = 0.25, 95% CI = 0.10-0.58). An increase of 1 mg/dl in serum calcium level was associated with a significant decrease in PC risk (OR = 0.52; 95% CI = 0.34-0.76). Our findings reveal the inverse association between serum total and ionized concentrations and PC risk, which supports the hypothesis that calcium may protect against PC. Furthermore, no evidence was found regarding age, BMI, and sex steroid hormones to modify the association between serum calcium and PC risk.

Determinants of serum levels of vitamin D: a study of life-style, menopausal status, dietary intake, serum calcium, and PTH

Background

Low blood levels of vitamin D (25-hydroxy D3, 25OHD3) in women have been associated with an increased risk of several diseases. A large part of the population may have suboptimal 25OHD3 levels but high-risk groups are not well known. The aim of the present study was to identify determinants for serum levels of 25OHD3 in women, i.e. factors such as lifestyle, menopausal status, diet and selected biochemical variables.

Methods

The study was based on women from the Malmö Diet and Cancer Study (MDCS), a prospective, population-based cohort study in Malmö, Sweden. In a previous case–control study on breast cancer, 25OHD3 concentrations had been measured in 727 women. In these, quartiles of serum 25OHD3 were compared with regard to age at baseline, BMI (Body Max Index), menopausal status, use of oral contraceptives or menopausal hormone therapy (MHT) , life-style (e.g. smoking and alcohol consumption), socio-demographic factors, season, biochemical variables (i.e. calcium, PTH, albumin, creatinine, and phosphate), and dietary intake of vitamin D and calcium. In order to test differences in mean vitamin D concentrations between different categories of the studied factors, an ANOVA test was used followed by a t-test. The relation between different factors and 25OHD3 was further investigated using multiple linear regression analysis and a logistic regression analysis.

Results

We found a positive association between serum levels of 25OHD3 and age, oral contraceptive use, moderate alcohol consumption, blood collection during summer/ autumn, creatinine, phosphate, calcium, and a high intake of vitamin D. Low vitamin D levels were associated with obesity, being born outside Sweden and high PTH levels.

Conclusions

The present population-based study found a positive association between serum levels of 25OHD3 and to several socio-demographic, life-style and biochemical factors. The study may have implications e. g. for dietary recommendations. However, the analysis is a cross-sectional and it is difficult to suggest Lifestyle changes as cause- effect relationships are difficult to assess.

Serum calcium and the calcium-sensing receptor polymorphism rs17251221 in relation to coronary heart disease, type 2 diabetes, cancer and mortality: the Tromsø Study

Serum calcium measured in 27,158 subjects in 1994 and the calcium-sensing receptor polymorphism rs17251221 genotyped in 9,404 subjects were related to cardiovascular risk factors, incident myocardial infarction (MI), type 2 diabetes (T2DM), cancer and death during follow-up until 2008-2010. In a Cox regression model with adjustment for age, gender, smoking and body mass index, subjects with serum calcium 2.50-2.60 mmol/L had a significantly increased risk of incident MI [n = 1,802, hazards ratio (HR) 1.40, 95 % confidence interval (CI) 1.18, 1.66] and T2DM (n = 705, HR 1.49, 95 % CI 1.15, 1.94) and a significantly reduced risk of cancer (n = 2,222, HR 0.73, 95 % CI 0.62, 0.86) as compared to subjects with serum calcium 2.20-2.29 mmol/L. For rs17251221 there was a mean difference in serum calcium of 0.05 mmol/L between major and minor homozygote genotypes. No consistent, significant relation between rs17251221 and risk factors or the major hard endpoints were found. The minor homozygote genotype (high serum calcium) had a significant twofold increased risk (HR 2.32, 95 % CI 1.24, 4.36) for prostate cancer, as compared to the major homozygote. This may be clinically important if confirmed in other cohorts.

A comparison of minimally invasive video-assisted parathyroidectomy and traditional parathyroidectomy for parathyroid adenoma

Background: Pre-operative imaging techniques for sporadic primary hyperparathyroidism (SPHPT) and intraoperative parathyroid hormone (ioPTH) have led to the wide spread use of minimally invasive surgical approaches.

Study Design: In our prospectively collected database, 157 subjects with SPHPT and a preoperative diagnosis of parathyroid adenoma were treated with parathyroidectomy between January 2003 and November 2011. Subjects in group A were enrolled between January 2003 to September 2006, and underwent traditional parathyroidectomy with intraoperative frozen section and bilateral neck exploration. Subjects in group B were enrolled between September 2006 to November 2011, and underwent minimally invasive video-assisted parathyroidectomy (MIVAP) with ioPTH. Operative times and post-operative pain levels were compared between groups. Subjects were followed for a minimum of 6 months post-operatively and recurrence rates and complication rates were measured between groups.

Results: 81 subjects were enrolled in group A, and 76 subjects were enrolled in group B. Pre-operative evaluation demonstrated that the groups were statistically similar. Significantly decreased operative times (28min vs. 62min) and post-operative pain levels were noted in group B. Recurrence rates were similar between group A (3.7%) and group B (2.6%).

Conclusions: MIVAP with ioPTH demonstrated significantly improved operative times and post-operative pain levels, while maintaining equivalent recurrence rates.

Is the risk of primary hyperparathyroidism increased in patients with untreated breast cancer?

BACKGROUND

An increased frequency of primary hyperparathyroidism (PHP) has been reported in patients with treated breast cancer (BC). PHP has been found in about 7% of BC patients after surgery and radio-, chemio- or hormonal therapy.

AIM

To evaluate the frequency of PHP in untreated BC patients.

SUBJECTS AND METHODS

We evaluated 186 women with BC and 233 women with thyroid cancer (TC, no.=122) or benign thyroid diseases (BTD, no.=111). In all patients, serum calcium, albumin, PTH, and 25-hydroxyvitamin D (25-OH vitD) were measured before any treatment.

RESULTS

Serum calcium concentrations were significantly higher in BC than in TC and BTD groups (median values 9.5 mg/dl, 9.3 mg/dl and 9.3 mg/dl, respectively) but, according to a logistic regression model, calcium was not significantly different between the 3 groups when age was taken into account. In all patients, serum calcium was in the normal range, indicating that no case of overt PHP was present. Five patients (1 in BC, 2 in TC, and 2 in BDT groups) had serum calcium close to the upper limit of normal range, high PTH and low 25-OH vitD, indicating a possible PHP with hypercalcemia masked by concomitant 25-OH vitD deficiency.

CONCLUSIONS

In untreated BC group, no patient had overt PHP and 1/186 (0.5%) presented a possible PHP masked by 25-OH vitD deficiency, a PHP frequency much lower than that observed in treated BC patients. These data suggest that the treatments of BC may be responsible for the increased frequency of PHP reported in previous studies.

Calcium intake is not related to breast cancer risk among Singapore Chinese women

There is experimental evidence that calcium protects against breast cancer development. Prospective epidemiologic studies supporting a protective effect of calcium on breast cancer risk have mainly been limited to Western populations. We examined the association between calcium intake and breast cancer risk in the Singapore Chinese Health Study, a large population-based prospective cohort. Calcium intake and supplement use was assessed by in-person interviewer using a validated food frequency questionnaire. After a mean follow-up of 14.2±3.5 years, 823 cohort participants developed invasive breast cancer. Multivariate proportional hazards regression models were fitted to examine the associations between calcium intake and breast cancer risk. Vegetables were the primary food source of calcium in this study population, followed by dairy products, grains and soy foods. Calcium intake was not associated with breast cancer risk, comparing highest quartile (>345.6 mg/1,000 kcal/day) to lowest quartile (<204.5 mg/1,000 kcal/day) of intake. There was no evidence of effect modification by menopausal status, body mass index, dietary vitamin D or stage of disease at diagnosis. Our findings do not support a hypothesis for calcium in breast cancer chemoprevention, contrary to findings from previous studies among Western populations with higher calcium intake primarily from dairy products and supplements.

Calcium nutrition and extracellular calcium sensing: relevance for the pathogenesis of osteoporosis, cancer and cardiovascular diseases

Through a systematic search in Pubmed for literature, on links between calcium malnutrition and risk of chronic diseases, we found the highest degree of evidence for osteoporosis, colorectal and breast cancer, as well as for hypertension, as the only major cardiovascular risk factor. Low calcium intake apparently has some impact also on cardiovascular events and disease outcome. Calcium malnutrition can causally be related to low activity of the extracellular calcium-sensing receptor (CaSR). This member of the family of 7-TM G-protein coupled receptors allows extracellular Ca2+ to function as a "first messenger" for various intracellular signaling cascades. Evidence demonstrates that Ca2+/CaSR signaling in functional linkage with vitamin D receptor (VDR)-activated pathways (i) promotes osteoblast differentiation and formation of mineralized bone; (ii) targets downstream effectors of the canonical and non-canonical Wnt pathway to inhibit proliferation and induce differentiation of colorectal cancer cells; (iii) evokes Ca2+ influx into breast cancer cells, thereby activating pro-apoptotic intracellular signaling. Furthermore, Ca2+/CaSR signaling opens Ca2+-sensitive K+ conductance channels in vascular endothelial cells, and also participates in IP(3)-dependent regulation of cytoplasmic Ca2+, the key intermediate of cardiomyocyte functions. Consequently, impairment of Ca2+/CaSR signaling may contribute to inadequate bone formation, tumor progression, hypertension, vascular calcification and, probably, cardiovascular disease.

Hyperparathyroidism: cancer and mortality

Hyperparathyroidism is a commoner endocrinopathy today with a large number of asymptomatic patients in contrast to the scenario five decades ago. Surgery is indicated for patients fulfilling the NIH criteria who are mostly symptomatic while individuals with mild disease are managed conservatively. Several studies indicate increased risk of malignancy involving several sites and related mortality in primary hyperparathyroidism (PHPT) with the risk persisting for several years after surgery. PHPT is associated with structural & functional cardiac abnormalities and premature death from increased cardiovascular disease with risk normalising only several years after surgery. Mortality risk is associated with pre-operative serum calcium & parathormone and parathyroid adenoma weight. However, the issue of existence of similar risk and surgical benefit in mild PHPT is mired in controversy although some studies have shown an association and beneficial trends with surgery. With current evidence, it would be prudent to follow up PHPT patients for malignancy and cardiovascular disease and possibly adopt a more liberal attitude towards surgery.

Serum calcium levels, TRPM7, TRPC1, microcalcifications, and breast cancer using breast imaging reporting and data system scores

BACKGROUND

An association between higher serum calcium (Ca²⁺) levels and breast cancer has been previously reported. However, little is known regarding the relationship between serum Ca²⁺ levels and the expression of Ca²⁺ channels in the presence of breast microcalcifications.

METHODS

A retrospective analysis of women newly diagnosed with breast microcalcifications was performed based on the Breast Imaging Reporting and Data System (BI-RADS). The expression of TRPC1, TRPC3, and TRPM7 using normal biopsy without microcalcifications (controls) and infiltrating ductal carcinoma with microcalcifications was evaluated.

RESULTS

Data on 138 women were analyzed. Seventy percent of women had a BI-RADS score (1-3) corresponding to benign disease. Seventy-six percent of women with a BI-RADS score (4 or 5) were diagnosed with breast cancer, 56% were cancers in situ, and 93% were infiltrating ductal carcinomas. No difference in the distribution of corrected serum Ca²⁺ levels between BI-RADS scores (1-3) and BI-RADS scores (4-5) (P = 0.82) was observed. Serum Ca²⁺ levels were similar in women without cancer and women diagnosed with breast cancer (P = 0.94). However, the expression of TRPM7 and TRPC1, but not TRPC3, Ca²⁺ channels were increased in infiltrating ductal carcinoma samples with microcalcifications when compared with age-matched controls without calcification or cancer.

CONCLUSION

We observed an increase in the expression of TRPM7 and TRPC1 Ca²⁺ channels in infiltrating ductal carcinoma samples with microcalcifications, whereas no change in serum Ca²⁺ levels was observed. Together these data suggest that increased expression of these channels might lead to an increase in intracellular Ca²⁺ levels thereby restoring serum Ca²⁺ levels, but these can contribute to the breast microcalcifications. However, future studies exploring the intracellular Ca²⁺ levels as well as the role of TRPM7 and TRPC1 function according to BI-RADS scores are needed.

Serum calcium, tumor size, and hormone receptor status in women with untreated breast cancer

Elevated serum levels of calcium are frequently observed in advanced breast cancer, but data on serum calcium and breast cancer characteristics at the time of breast cancer diagnosis are limited. We conducted a cross-sectional study of 555 women with newly-diagnosed, untreated breast cancer in North Dakota. We examined the relationship between tumor size, serum calcium and other clinical characteristics of breast tumors, including age and hormone receptor status, using multiple linear regressions. Tumors that were estrogen receptor negative tended to be associated with higher serum calcium levels (p = 0.07). We observed a significant positive correlation between tumor volume and serum calcium levels (adjusted for patient age, body mass index, hormonal receptors, stage at diagnosis, and grade). The association between tumor volume and serum calcium was limited to post-menopausal women. Our finding that postmenopausal women with larger breast tumors had significantly higher serum calcium levels is consistent with a calciotropic effect of early breast cancer in postmenopausal women.

Lower blood calcium associates with unfavorable prognosis and predicts for bone metastasis in NSCLC

Ionized calcium was involved in various cellular signal pathways,and regulates many cellular processes, including those relevant to tumorigenesis. We hypothesis that imbalance of calcium homeostasis is correlated with development of lung carcinomas. We collected the clinical data of 1084 patients with non small cell lung cancer (NSCLC) treated in Shandong Provincial Hospital, Shandong University. Logistic regression was used to determine the association between calcium levels and clinical characteristics, and COX regression and Kaplan-Meier model were applied to analyze risk factors on overall survival. Blood electrolytes were tested before treatment; and nearly 16% patients with NSCLC were complained with decreased blood calcium, which is more frequent than that in other electrolytes. Further, Multivariate logistic regression analysis disclosed that there were significant correlation between blood calcium decrease and moderate and poor differentiation (P = 0.012, OR = 1.926 (1.203-4.219)), squamous cell carcinoma (P = 0.024, OR = 1.968(1.094-3.540)), and bone metastasis (P = 0.032, OR = 0.396(0.235-0.669)). In multivariate COX regression analysis, advanced lymph node stage and decreased blood calcium were significantly and independent, unfavorable prognostic factors (P<0.001). Finally, the Kaplan-Meier Survival curve revealed that blood calcium decrease was associated with shorter survival (Log-rank; χ(2) = 26.172,P<0.001). Our finding indicates that lower blood calcium levels are associated with a higher risk of unfavorable prognosis and bone metastasis of NSCLC.

Abandoning unilateral parathyroidectomy: why we reversed our position after 15,000 parathyroid operations

BACKGROUND

Our group championed the techniques and benefits of unilateral parathyroidectomy. As our experience has matured, it seems this limited operation might be appropriate only occasionally.

METHODS

A single surgical group's experience with 15,000 parathyroidectomies examined the ongoing differences between unilateral and bilateral techniques for 10-year failure/recurrence, multigland removal, operative times, and length of stay.

RESULTS

With limited experience, 100% of operations were bilateral, decreasing to 32% by the 500(th) operation (p < 0.001), and long-term failure rates increased to 6%. Failures were 11 times more likely for unilateral explorations (p < 0.001 vs bilateral), causing gradual increases in bilateral explorations to 97% at the 14,000(th) operation (p < 0.001). Ten-year cure rates are unchanged for bilateral operations, and unilateral operations show continued slow recurrence rates of 5% (p < 0.001). Removal of more than one gland occurred 16 times more frequently when 4 glands were analyzed (p < 0.001), increasing cure rates to the current 99.4% (p < 0.001). Of 1,060 reoperations performed for failure at another institution, intraoperative parathyroid hormone levels fell >50% in 22% of patients, yet a second adenoma was subsequently found. Operative times decreased with experience; bilateral operations taking only 5.9 minutes longer on average (22.3 vs 16.4 minutes; p < 0.001), which is 25 minutes less than unilateral at the 500(th) operation (p < 0.001). By the 1,000(th) operation, incision size (2.5 ± 0.2 cm), anesthesia, and hospital stay (1.6 hours) were identical for unilateral and bilateral procedures.

CONCLUSIONS

Regardless of surgical adjuncts (scanning, intraoperative parathyroid hormone), unilateral parathyroidectomy will carry a 1-year failure rate of 3% to 5% and a 10-year recurrence rate of 4% to 6%. Allowing rapid analysis of all 4 glands through the same 1-inch incision has caused us to all but abandon unilateral parathyroidectomy.

The role of bone microenvironment, vitamin D and calcium

Starting first from Paget's "seed and soil" to the latest hypothesis about metastatic process involving the concept of a premetastatic niche, a large amount of data suggested the idea that metastatization is a multistep coordinated process with a high degree of efficiency. A specific subpopulation of cells with tumor-initiating and migratory capacity can selectively migrate toward sites that are able to promote survival, and/or proliferation of metastatic tumor cells through a microenvironment modification. Bone plays a pivotal role in this process, acting not only as a preferential site for cancer cells' homing and proliferation, due to a complex interplay between different cellular phenotypes such as osteoblasts and osteoclasts, but also as a source of bone marrow precursors that are able to facilitate the metastatic process in extra-skeletal disease. Moreover, bone microenvironment has the unique capacity to retain cancer stem cells in a quiescent status, acting as a reservoir that is able to cause a metastatic spread also many years after the resection of the primary tumor. To add a further level of complexity, these mechanisms are strictly regulated through the signalling through several soluble factors including PTH, vitamin D or calcium concentration. Understanding this complexity represents a major challenge in anti-cancer research and a mandatory step towards the development of new drugs potentially able not only to reduce the consequences of bone lesions but also to target the metastatization process from the "bone pre-neoplastic niche" to "visceral pre-neoplastic niches".

Urinary strontium and the risk of breast cancer: a case-control study in Guangzhou, China

Strontium has been widely used in industries like electronic and pharmacy. It has a carcinogenic potential, however, and no study has been conducted to evaluate its effects on cancer risk. The aim of this study was to explore the possible association between strontium and breast cancer risk in a case-control study including 240 incident invasive breast cancer patients and 246 age-matched controls. We measured the urinary concentrations of strontium by inductively coupled plasma mass spectrometry, and conducted face-to-face interviews to obtain information on potential breast cancer risk factors. Multivariable analysis was used to estimate the association. Creatinine-adjusted levels [median (25th, 75th) μg/g] of strontium were 155.59 (99.05, 230.70) in the breast cancer patients and 119.62 (81.97, 163.76) in the controls. Women in the highest tertile of strontium showed 124% increased risk of breast cancer, when compared with those in the lowest tertile after adjustment for the potential risk factors [OR (95% CI): 2.24 (1.42-3.81)]. This association was particularly strong for HER2 positive breast cancer [OR (95% CI): 10.92 (3.53-33.77)], and only occurred among premenopausal women. These results suggest a potential role of strontium in the development of breast cancer and urge further studies on the environmental contamination and the physiological and pathological mechanisms of strontium.

The vitamin D pathway and mammographic breast density among postmenopausal women

Laboratory studies have demonstrated that vitamin D has a number of chemopreventive properties, and that these properties may be mediated or modified by other molecules in the vitamin D pathway, such as parathyroid hormone (PTH) or calcium. However, there is little epidemiologic data exploring the effects of vitamin D on breast cancer risk in the context of these other molecules. We examined a panel of molecules in the vitamin D pathway in relation to mammographic breast density, a marker of breast cancer risk, in the Wisconsin Breast Density Study. A total of 238 postmenopausal women (ages 55-70, with no history of postmenopausal hormone use) were enrolled from mammography clinics in Madison, Wisconsin. Subjects provided blood samples that were analyzed for levels of 25-hydroxy vitamin D [25(OH)D], PTH, insulin-like growth factor-1 (IGF-1), IGF-binding protein 3 (IGFBP-3), retinol, and calcium. Percent breast density was measured using Cumulus software. In age-adjusted analyses there was a positive association between 25(OH)D and percent breast density (P = 0.05; mean percent density = 11.3% vs. 15.6% for 1st vs. 4th quartile of 25(OH)D). Breast density was inversely associated with PTH (P = 0.05; 16.0% vs. 11.4% for Q1 vs. Q4) and positively associated with the IGF-1:IGFBP-3 molar ratio (P = 0.02; 11.9% vs. 15.6% for Q1 vs. Q4). However, these associations were all null after further adjustment for body mass index (BMI; P > 0.25). The independent relation between 25(OH)D and breast density remained null among subgroups defined by BMI and serum levels of retinol, calcium, and estradiol. These results suggest no strong independent associations between the circulating molecules of the vitamin D pathway and mammographic breast density in postmenopausal women. While it remains possible that vitamin D could influence breast cancer risk, our results suggest that such an effect would be mediated through pathways other than breast density.

Breast cancer associated with primary hyperparathyroidism: a nested case control study

Background:

Primary hyperparathyroidism (pHPT) is associated with an increased risk of developing breast cancer, but little is known about the underlying factors. The aim of this study was to compare women with a history of pHPT and a reference population in terms of standard factors predictive of prognosis and response to therapy for breast cancer.

Methods:

We analyzed data collected from the National Swedish Cancer Register and from two regional oncologic center registries. Seventy-one women with breast cancer and a history of parathyroid adenomectomy were compared with 338 matched controls with breast cancer only. Tumor size, stage, hormone receptor status, lymph node status, cause of death, and cumulative survival were analyzed.

Results:

The mean age was 69 ± 11 years (95% confidence interval [CI]: 68–70) in both groups and the mean time interval between the parathyroid surgery and breast cancer diagnosis was 91 ± 68 months (95% CI: 72–111). There were no differences between the two groups regarding size, stage, lymph node metastases, or survival, but none of the cases with a history of pHPT were found in Stage III or IV.

Conclusion:

In conclusion, factors predictive of prognosis and response to therapy in women with a history of pHPT and breast cancer are similar to those in breast cancer patients without pHPT.

The role of calcium in the activation of estrogen receptor-alpha

Environmental estrogen mimics, including metalloestrogens that can activate estrogen receptor-alpha (ERα), may contribute to breast cancer risk. However, the underlying mechanisms through which these molecular mimics activate the ERα are generally poorly understood. With concern to this important question, we investigated whether intracellular calcium may mediate the cross-talk between signaling pathways that activate ERα and the ligand-binding domain of ERα. MCF-7 cells treated with EGF, ATP, extracellular calcium, or caffeine to increase intracellular calcium triggered a rapid recruitment of ERα to estrogen-responsive promoters and stimulated expression of estrogen-responsive genes including pS2, complement C3, and progesterone receptor. Induction was blocked by an antiestrogen but also by the chelation of intracellular calcium. Treatment with extracellular calcium also increased the growth of MCF-7 cells through an ER-dependent mechanism. We found that EGF and extracellular calcium activated the C-terminus of ERα and the activation was blocked by the antiestrogen. Mechanistic investigations identified four potential sites on the solvent-accessible surface of the ERα ligand-binding domain as important for calcium activation of the receptor. Taken together, our results suggest that calcium mediates the cross-talk between ERα-activating signaling pathways and the ligand-binding domain of ERα providing a potential explanation for the ability of certain environmental metalloestrogens to activate the receptor.

Serum levels of vitamin D, PTH and calcium and breast cancer risk-a prospective nested case-control study

Previous studies indicate that calcium and its regulating hormones, i.e., parathyroid hormone (PTH) and vitamin D, might affect breast cancer risk. Evidence also suggests that this relationship could be influenced by menopausal status and BMI. We examined breast cancer risk related to prediagnostic serum levels of vitamin D (25OHD(2) and 25OHD(3)), PTH and calcium using a nested case-control design within the Malmö Diet and Cancer Study. There were 764 incident breast cancer cases, and 764 controls were selected by incidence density matching, using age as the underlying time scale, matching on calendar time at inclusion, menopausal status and age at inclusion. Using logistic regression analysis, odds ratios (OR) with 95% confidence intervals were calculated for breast cancer risk in different quartiles of the analyzed factors. All analyses were adjusted for risk factors for breast cancer, and for levels of albumin, creatinine and phosphate. Analyses were repeated stratified for BMI and menopausal status, and for low vs. high levels of 25OHD(3), PTH and calcium. There was a weak, nonsignificant inverse association between breast cancer risk and 25OHD(3), and the OR for the 2nd, 3rd and 4th quartiles, as compared to the first, were 0.84 (0.60-1.15), 0.84 (0.60-1.17) and 0.93 (0.66-1.33). Serum calcium was positively associated with breast cancer in premenopausal women (OR for the 4th quartile = 3.10:1.33-7.22 and p for quartile trend = 0.04), and in women with BMI > 25 (OR for the 4th quartile = 1.94:1.12-3.37 and p for trend < 0.01). There was no association between baseline serum PTH and breast cancer risk.

Dairy consumption and calcium intake and risk of breast cancer in a prospective cohort: the Norwegian Women and Cancer study

Objective

To study the association between consumption of dairy products and calcium intake and risk of breast cancer risk according to menopausal status.

Methods

In a population-based prospective cohort study of 64,904 Norwegian women followed from 1996/1999 through 2006, we examined total dairy consumption and consumption of various dairy products in relation to pre- and postmenopausal breast cancer risk. We also examined breast cancer in relation to calcium intake and to milk consumption during childhood and performed additional analyses corrected for measurement errors in the dietary data. In total, 218 premenopausal and 1,189 postmenopausal incident breast cancer cases were diagnosed during follow-up.

Results

Total dairy, adult, and childhood milk consumption was not associated with either pre- or postmenopausal breast cancer risk. Premenopausal women with the highest consumption of white cheese had half the risk of breast cancer compared to those with the lowest consumption (hazard rate ratio in the 4th quartile vs. the 1st quartile 0.50, 95% confidence interval 0.29–0.87). Total calcium intake tended to be inversely related to premenopausal (hazard rate ratio in the 4th quartile vs. the 1st quartile 0.65, 95% confidence interval 0.39–1.08) and postmenopausal breast cancer (hazard rate ratio in the 4th quartile vs. the 1st quartile 0.85, 95% confidence interval 0.70–1.04). Correcting for measurement errors did not alter the results substantially, nor did exclusion of early cancer cases.

Conclusion

Dairy consumption is not strongly related to breast cancer risk in this prospective study. A non-significant negative association between calcium intake and breast cancer risk was seen, particularly among premenopausal women.

Vitamin D and calcium intakes and breast cancer risk in pre- and postmenopausal women

BACKGROUND

Some evidence suggests that vitamin D may reduce breast cancer risk. Despite the biological interaction between vitamin D and calcium, few studies have evaluated their joint effects on breast cancer risk.

OBJECTIVE

The objective was to evaluate the associations and potential interaction between vitamin D and calcium (from food and supplements) and breast cancer risk in a population-based case-control study.

DESIGN

Breast cancer cases aged 25-74 y (diagnosed 2002-2003) were identified through the Ontario Cancer Registry. Controls were identified by using random digit dialing; 3101 cases and 3471 controls completed epidemiologic and food-frequency questionnaires. Adjusted odds ratios (ORs) and 95% CIs were estimated by using multivariate logistic regression.

RESULTS

Vitamin D and calcium intakes from food only and total combined intakes (food and supplements) were not associated with breast cancer risk, although the mean intake of vitamin D was low. Vitamin D supplement intake >10 microg/d (400 IU/d) compared with no intake was associated with a reduced risk of breast cancer (adjusted OR: 0.76; 95% CI: 0.59, 0.98). No categories of calcium supplement intake were significantly associated with reduced breast cancer risk, but a significant inverse trend was observed (P = 0.04). There were no significant interactions involving vitamin D, calcium, or menopausal status.

CONCLUSIONS

No associations were found between overall vitamin D or calcium intake and breast cancer risk. Vitamin D from supplements was independently associated with reduced breast cancer risk. Further research is needed to investigate the effects of higher doses of vitamin D and calcium supplements.

Assessing women at high risk of breast cancer: a review of risk assessment models

Women who are at high risk of breast cancer can be offered more intensive surveillance or prophylactic measures, such as surgery or chemoprevention. Central to decisions regarding the level of prevention is accurate and individualized risk assessment. This review aims to distill the diverse literature and provide practicing clinicians with an overview of the available risk assessment methods. Risk assessments fall into two groups: the risk of carrying a mutation in a high-risk gene such as BRCA1 or BRCA2 and the risk of developing breast cancer with or without such a mutation. Knowledge of breast cancer risks, taken together with the risks and benefits of the intervention, is needed to choose an appropriate disease management strategy. A number of models have been developed for assessing these risks, but independent validation of such models has produced variable results. Some models are able to predict both mutation carriage risks and breast cancer risk; however, to date, all are limited by only moderate discriminatory accuracy. Further improvements in the knowledge of how to best integrate both new risk factors and newly discovered genetic variants into these models will allow clinicians to more accurately determine which women are most likely to develop breast cancer. These steady and incremental improvements in models will need to undergo revalidation.

Does a higher ratio of serum calcium to magnesium increase the risk for postmenopausal breast cancer?

Breast cancer is the most commonly diagnosed cancer among United States (US) women. Established risk factors explain only about 13% of breast cancer incidence among women in the US. Thus, the cause of most cases of breast cancer remains unknown. In postmenopausal women, serum calcium (Ca) and serum magnesium (Mg) play an important role in skeletal health, cell proliferation and cancer. Mg is essential for DNA duplication and repair and Mg deficiency favors DNA mutations leading to carcinogenesis. Dietary intake of Mg in the US is less than the recommended amount, and the deficit is more pronounced in older individuals where gastrointestinal and renal mechanisms for Mg conservation are not as efficient. Furthermore, healthy postmenopausal women are frequently recommended to take supplemental Ca, but not Mg and vitamin D to maintain bone and overall health. Most women with hormone sensitive breast cancer are recommended to take aromatase inhibitors, which causes bone loss and thus are generally prescribed Ca and vitamin D, but not Mg. Although the association between serum Ca and breast cancer risk remains controversial, we hypothesize that this may be because Mg levels have not been accounted for. Mg level directly influences transient receptor potential melastatin 7 (TRPM7) related Ca influx, calcium-adenosine triphosphatase (Ca-ATP) levels, and cell proliferation, and thereby could lead to cancer. Thus a high serum Ca/Mg ratio is more appropriate and alterations in this ratio could lead to increased development of new and recurrent breast cancer.

Serum calcium and breast cancer risk in a prospective cohort study

Calcium has anti-proliferative and pro-differentiation effects on mammary cells in vitro and can inhibit the development of mammary tumors in mice. While there is some epidemiologic evidence for an inverse relation between dietary calcium intake and breast cancer risk, only one previous study has examined serum calcium levels in relation to breast cancer risk. We investigated this relation in a prospective cohort study of 2,762 women, aged 43-86, who were enrolled in the Beaver Dam Eye Study in 1988 and followed for up to 19 years. We found no evidence for an association between breast cancer risk and either total (hazard ratio, HR = 0.98; 95% CI: 0.60-1.60; 4(th) vs. 1(st) quartile) or ionized (HR = 0.85; 95% CI: 0.53, 1.38; 4(th) vs. 1(st) quartile) serum calcium levels. Additionally, we found no evidence for an association among subgroups defined by menopausal status and body mass index.

Serum calcium levels are elevated among women with untreated postmenopausal breast cancer

OBJECTIVE

Reports of an association between primary hyperparathyroidism in women and risk of breast cancer suggest an etiologic role for high serum calcium. However, data on the association between serum calcium levels and breast cancer in women without clinical hyperparathyroidism are limited.

METHODS

We conducted a hospital-based case-control study among postmenopausal women in Fargo, ND. Cases were women aged 65 and older with newly diagnosed, histologically confirmed breast cancer. Controls were aged 65 and older without clinical cancer who were seen at the same hospital.

RESULTS

We obtained data on 190 white cases and 172 white controls. Primary hyperparathyroidism (an abnormally high calcium level confirmed by an abnormally high serum PTH) was found in 3/190 cases and in 0/172 controls (p = 0.25). After excluding the women with primary hyperparathyroidism, the mean calcium levels among cases was 9.6 mg/dL (range, 7.5-11.0, SD = 0.47) vs. 9.4 mg/dL (7.7-10.5, 0.43) among the controls (p < 0.0001). Comparing women in the top with women in the bottom tertile of serum calcium, the multivariable-adjusted odds ratio (OR) for breast cancer was 5.21 (95% CI: 2.59-10.48). There was no relationship between serum calcium and tumor size or stage.

CONCLUSION

The distribution of serum calcium levels among postmenopausal women with incident breast cancer was shifted significantly toward the right. These findings are consistent with an effect of early breast tumors on calcium homeostasis. However, the lack of association between serum calcium levels and tumor size or stage supports the hypothesis that subclinical hyperparathyroidism may increase the risk for breast cancer.

Serum calcium and tumour aggressiveness in breast cancer: a prospective study of 7847 women

Experimental, epidemiological and clinical studies suggest that calcium and/or its regulating hormones affect breast cancer risk. There has been no prospective cohort study investigating serum calcium levels and breast cancer aggressiveness, as determined by tumour histology and stage. Dichotomized prediagnostic serum calcium levels were investigated in relation to breast cancer aggressiveness as determined by grade (mitotic frequency, tubule formation, nuclear atypia) and stage (tumour size and axillary lymph node status). Cox's proportional hazards analysis and heterogeneity analysis were used to investigate the associations between low/high calcium and grade/stage in a prospective cohort study of 7847 women, out of whom 462 women were diagnosed with incident breast cancer during a mean follow-up of 17.2 years. All analyses were stratified for body mass index and menopausal status. Prediagnostic serum calcium levels in premenopausal women were positively associated with increased tumour aggressiveness as determined by a higher risk of nodal metastasis; relative risk (RR) for calcium above median as compared with calcium below median was 1.88 with a 95% confidence interval (CI) of 1.04-3.38. In overweight women, prediagnostic serum calcium levels were also associated with tumour aggressiveness, as determined by both a higher risk of nodal metastasis [RR (95% CI) 1.69 (0.95-3.02)] and severe nuclear atypia [RR (95% CI) 2.06 (1.10-3.86)]. Results also indicate that, in overweight women, calcium is positively associated with worse grade as determined by tubule formation and mitotic frequency. In conclusion, prediagnostic serum calcium levels are positively associated with increased tumour aggressiveness in premenopausal and/or overweight women.

Vitamin D and calcium insufficiency-related chronic diseases: molecular and cellular pathophysiology

A compromised vitamin D status, characterized by low 25-hydroxyvitamin D (25-(OH)D) serum levels, and a nutritional calcium deficit are widely encountered in European and North American countries, independent of age or gender. Both conditions are linked to the pathogenesis of many degenerative, malignant, inflammatory and metabolic diseases. Studies on tissue-specific expression and activity of vitamin D metabolizing enzymes, 25-(OH)D-1 alpha-hydroxylase and 25-(OH)D-24-hydroxylase, and of the extracellular calcium-sensing receptor (CaR) have led to the understanding of how, in non-renal tissues and cellular systems, locally produced 1,25-dihydroxyvitamin D(3) (1,25-(OH)(2)D(3)) and extracellular Ca(2+) act jointly as key regulators of cellular proliferation, differentiation and function. Impairment of cooperative signalling from the 1,25-(OH)(2)D(3)-activated vitamin D receptor (VDR) and from the CaR in vitamin D and calcium insufficiency causes cellular dysfunction in many organs and biological systems, and, therefore, increases the risk of diseases, particularly of osteoporosis, colorectal and breast cancer, inflammatory bowel disease, insulin-dependent diabetes mellitus type I, metabolic syndrome, diabetes mellitus type II, hypertension and cardiovascular disease. Understanding the underlying molecular and cellular processes provides a rationale for advocating adequate intake of vitamin D and calcium in all populations, thereby preventing many chronic diseases worldwide.

Secondary causes of low bone mass in patients with breast cancer: a need for greater vigilance

PURPOSE

An observational study to assess the prevalence of secondary causes of low bone density in patients with breast cancer.

PATIENTS AND METHODS

Female patients within 5 years of breast cancer diagnosis and age older than 50 years at diagnosis were recruited. Consenting patients completed a questionnaire and had blood taken for serum calcium, vitamin D, parathyroid hormone (PTH), and thyroid function testing. Bone mineral density (BMD) was assessed. Abnormalities were additionally investigated and treated.

RESULTS

Two hundred patients were recruited. The median age at diagnosis was 62 years. One hundred sixty-nine patients had hormone receptor (HR) -positive cancer. Vitamin D and thyroid function were assessed in 200 patients; PTH was assessed in 197 patients; and BMD was assessed in 187 patients. Eighty-seven patients (46.5%) had osteopenia, and 24 patients (12.8%) had osteoporosis. Vitamin D levels were insufficient (ie, 50 to 75 nmol/L) in 74 patients (37%) and were deficient (ie, < 50 nmol/L) in 54 patients (27%). Only 24 of 65 patients taking vitamin D supplements were replete (ie, > 75 nmol/L). Thirty-nine (21%) of 197 patients had PTH concentrations greater than the normal range. Six had primary hyperparathyroidism (PHPT), and two more had recent surgery for PHPT. Twenty-seven had secondary hyperparathyroidism (HPT) from vitamin D deficiency and six had normocalcemic HPT. Of 90 patients with low BMD and HR-positive cancer, 8% (seven of 90 patients) had new or recent PHPT, and 63% (57 of 90 patients) had insufficient or deficient vitamin D. More patients with HR-positive cancer than with HR-negative cancer had elevated PTH (38 of 167 v three of 30 patients, respectively; P = .10).

CONCLUSION

Secondary causes of low BMD are common in postmenopausal women. Identification and management of secondary causes should be included in bone health management algorithms.

Serum calcium and the risk of prostate cancer

BACKGROUND

Recent studies have suggested an association between high dietary intake of calcium and the risk of prostate cancer. Calcium-rich diet has been suggested to affect the serum levels of Vitamin D, and thereby promote cancer. We conducted the largest study of the association between prediagnostic serum levels of calcium and the risk of prostate cancer.

OUTLINE

We examined the incidence of prostate cancer in relation to prediagnostic serum calcium levels in a prospective cohort study of 22,391 healthy Swedish men, of which 1,539 incident cases of prostate cancer were diagnosed during the 30 years of follow-up until December 2006.

MATERIAL AND METHODS

Serum levels of calcium were measured at baseline, and categorized into quartiles. Cox regression was used to estimate the adjusted hazard ratios (HR) with 95% confidence intervals (CI).

RESULTS

We found no evidence of an association between prediagnostic serum levels of calcium and risk of prostate cancer (HR for trend = 0.99 [95% CI;0.94-1.03]). However, a moderate significant negative association was seen in men with a BMI above 25 and aged below 45 years at baseline (Highest vs. lowest quartile, HR = 0.63 [95% CI;0.40-0.99]).

CONCLUSION

These data do not support the hypothesis that high serum calcium levels is a risk factor for prostate cancer. On the contrary, the data suggest that high serum levels of calcium in young overweight men may be a marker for a decreased risk of developing prostate cancer.

Calcium plus vitamin D supplementation and the risk of breast cancer

BACKGROUND

Although some observational studies have associated higher calcium intake and especially higher vitamin D intake and 25-hydroxyvitamin D levels with lower breast cancer risk, no randomized trial has evaluated these relationships.

METHODS

Postmenopausal women (N = 36 282) who were enrolled in a Women's Health Initiative clinical trial were randomly assigned to 1000 mg of elemental calcium with 400 IU of vitamin D(3) daily or placebo for a mean of 7.0 years to determine the effects of supplement use on incidence of hip fracture. Mammograms and breast exams were serially conducted. Invasive breast cancer was a secondary outcome. Baseline serum 25-hydroxyvitamin D levels were assessed in a nested case-control study of 1067 case patients and 1067 control subjects. A Cox proportional hazards model was used to estimate the risk of breast cancer associated with random assignment to calcium with vitamin D(3). Associations between 25-hydroxyvitamin D serum levels and total vitamin D intake, body mass index (BMI), recreational physical activity, and breast cancer risks were evaluated using logistic regression models. Statistical tests were two-sided.

RESULTS

Invasive breast cancer incidence was similar in the two groups (528 supplement vs 546 placebo; hazard ratio = 0.96; 95% confidence interval = 0.85 to 1.09). In the nested case-control study, no effect of supplement group assignment on breast cancer risk was seen. Baseline 25-hydroxyvitamin D levels were modestly correlated with total vitamin D intake (diet and supplements) (r = 0.19, P < .001) and were higher among women with lower BMI and higher recreational physical activity (both P < .001). Baseline 25-hydroxyvitamin D levels were not associated with breast cancer risk in analyses that were adjusted for BMI and physical activity (P(trend) = .20).

CONCLUSIONS

Calcium and vitamin D supplementation did not reduce invasive breast cancer incidence in postmenopausal women. In addition, 25-hydroxyvitamin D levels were not associated with subsequent breast cancer risk. These findings do not support a relationship between total vitamin D intake and 25-hydroxyvitamin D levels with breast cancer risk.