[The role of calcium in the chemoprevention of colorectal cancer]


SEPTEMBER 20, 2005

Ca&Bone - 2005;8(03)

[One of the most exciting research areas of the past decade has concerned the chemoprevention of colorectal cancer (CRC). Numerous clinical studies have been conducted on the preventive role of NSAIDs, high fibre intake, selenium, phytooestrogens, hormone replacement therapy, antioxidants, COX-inhibitors, folic acid and calcium, however, their results are controversial. Among the suggested chemopreventive agents, the preventive role of calcium is supported by the strongest evidence.This paper aims to review the available facts on the role of calcium. Recent studies suggest that appropriate calcium intake may partially counterbalance the effect of the genes that contribute to the development of CRC. Experimental data show that calcium directly influences the expression of several genes involved in tumorigenesis and that it is also involved in a number of signalling pathways that control cell proliferation, differentiation and apoptosis.These effects mostly arise through the activation of the calcium sensing receptor. The main goal of this review is to draw attention to the established chemopreventive role of calcium in CRC. Published data suggest that a lifelong daily calcium intake between 1200 to 1500 mg (even 2000 mg in high risk groups) would significantly decrease the incidence of CRC by inhibition of tumorigenesis.]



Further articles in this publication


[Serum 25(OH)-Vitamin D levels and bone metabolism in patients on maintenance hemodialysis]


[INTRODUCTION - Increasing evidence suggests that 25- hydroxy vitamin D3 (25(OH)D3) may contribute to the bone health of patients with chronic kidney disease.However, there is very little information available on the vitamin D3 status of patients with chronic renal failure. In a cross-sectional study we assessed the association between vitamin D3 status and parathyroid function, bone turnover, bone mass and structure in patients on maintenance haemodialysis. PATIENTS AND METHODS - Sixty-nine patients on maintenance haemodialysis were assessed by bone densitometry (DEXA) and quantitative bone ultrasound. Serum 25-hydroxy vitamin D3 levels and serum markers of bone turnover were simultaneously measured. RESULTS - A high prevalence of potentially significant vitamin D3 deficiency was found in this patient group; 59% of the patients had their 25(OH)D3 vitamin level below 20 nmol/l.There was a significant negative correlation between serum 25(OH)D3 and serum intact parathormone (iPTH) levels (r=-0.231, p<0.05) and this association remained significant after controlling for potential co-variables. Furthermore, a positive correlation was observed between serum 25(OH)D3 concentration and bone mineral density measured at the radius (r=0.424, p<0.01). Finally,we show for the first time that 25(OH)D3 levels are significantly and independently associated with broad band ultrasound attenuation (β =0.237, p<0.05) measured with calcaneal quantitative bone ultrasound in patients with chronic renal failure. CONCLUSION - Vitamin D3 deficiency may contribute to the impaired bone health of patients on maintenance dialysis, therefore, it seems to be warranted regularly monitoring and carefully controlling the D3-vitamin level of these patients.The results also suggest that quantitative bone ultrasound is useful in assessing bone health of patients with chronic renal failure.]


[About risk factors of osteoporotic fractures - Fractures of bones, quality of bone, age, quality of life]



[Hungarian and international results in compliance of antiporotic treatment]


[The studies investigate the compliance of treatment showed that the compliance is one of the most important factor which influence the success of an otherwise effective treatment. Not only the patients, but also the doctors and nurses are responsible for the unsuccessful treatment. Our article shortly review Hungarian and international data about the compliance of antiporotic treatment and summarises a study which we plan to achieve in the near future.]


[The effect of sex hormone replacement on radial bone mineral content in boys with panhypopituitarism]


[INTRODUCTION - Children with pituitary insufficiency normally receive growth hormone and thyroid hormone substitution, but glucocorticoid treatment is rarely necessary. Sex hormone replacement is introduced in puberty, which, at the same time, promotes growth and bone maturation. In this study the effect of testosterone replacement on bone mineral content was examined. PATIENTS AND METHODS - Nine boys (16.3±1.3 years) with hypopituitarism were involved in the study who had been receiving growth hormone and thyroid hormone replacement for several years by the beginning of the study.Androgen was substituted by the intramuscular administration of 50 mg testosterone biweekly.The children's height,weight, the rate of pubescence, and bone age were checked, and bone mineral density was measured by single photon absorptiometry every six month. During the substitution treatment serum thyroxin and testosterone levels remained in the normal ranges. RESULTS - A significant increase in bone mineral density was observed during the testosterone treatment, with Z-scores -1.80, -0.91 and +0.14 at baseline, 12 and 24 months, respectively (p<0,001). Z-scores adjusted for bone age remained in the normal range throughout the study (-0.904 at baseline and -0.946 at one year). CONCLUSION - The increase rate of bone mineral density (0.16 g/cm/year) was significantly higher compared both to the normal reference in this age group (0.07 g/cm/yr, p=0.0015) and to the normal reference relative to their bone age (p<0.0006). The increase in bone mineral density suggests that testosterone replacement has an important role both in the quantitative and qualitative development of bones.]


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All articles in the issue

Related contents


[The role of alfacalcidol in the prevention of osteopenia following renal transplantation]


[AIM - The aim of this prospective study was the long-term evaluation of the effect of calcium and alfacalcidol treatment on calcium metabolism in patients with renal transplantation. METHODS - Patients were divided in two groups. Patients in Group 1 (n=159) received calcium substitution, while patients in Group 2 (n=81) were treated with alfacalcidol. Serum Ca, P, Mg, alkaline phosphatase (AP) and PTH levels were determined before and after transplantation regularly for three years. Femur neck and lumbar vertebral bone mineral densities (BMD) were measured at the same time after transplantation. RESULTS - After transplantation the mean serum calcium level significantly increased, while the mean serum phosphate level significantly decreased in both groups. After the operation the PTH levels decreased in both groups and it was found to be more pronounced in the alfacalcidol group.The majority of patients had osteopenia in the follow-up period. Between the third month and the third year after transplantation, BMD increased by 9.4% in Group1, and decreased by 4% in Group 2 at the lumbar spine. At 3 years the mean BMD value at the femoral neck was increased by 6.5% in Group 1, and by 6.7% in Group 2, compared to the 3-month values.The change in BMD was only significant at the lumbar spine, in Group 1 (p=0.019). During the follow-up period osteonecrosis was diagnosed in 6 patients in Group 1 and in 9 cases in Group 2. CONCLUSION - Alfacalcidol treatment decreased secondary hyperparathyroidism more rapidly and effectively, which was also indicated by the more pronounced decrease of serum PTH levels. During the 3 years follow-up period, BMD increased in both groups except for the lumbar spine in Group 2, however, the majority of the patients still had osteopenia.The study could not demonstrate a superiority of alfacalcidol over calcium supplementation in the prevention of posttransplantational osteopenia.]

Clinical Oncology

[Why don’t immune checkpoint inhibitors work in colorectal cancer?]

SHI Yuequan, ZOU Zifang, KERR David

[In recent years, immune checkpoint inhibitors have been shown to be effective in treating manifold types of cancer but less robust in colorectal cancer (CRC). While, the subgroup of CRC with microsatellite instability (MSI; also termed as mismatch repair defi cient) showed a moderate response to Pembrolizumab in a single arm phase II clinical trial, microsatellite stable (MSS) cancers were unresponsive. Possible mechanisms that affect immune response in colorectal cancer will be reviewed in this article. We will also propose that histone deacetylase (HDAC) inhibition may reverse the immune editing commonly seen in advanced CRC and render them sensitive to immune checkpoint blockade.]

Lege Artis Medicinae

[Systemic adjuvant pharmacotherapy of colorectal cancer]


[Colorectal cancer is one of the most frequent cancer in the postindustrial world; its most common form is adenocarcinoma. In Hungary, colorectal cancer has the second highest mortality among tumours. If diagnosed early, it might be successfully treated by surgery, however, chemotherapy is necessary to prevent tumor relapse and development of metastases and achieve adequate palliation. In the past few years, adjuvant treatment of colorectal cancer has improved substantially. Many new drugs have been developed, which are also being used in combination with previously known agents. This article will discuss the novelties in the field of adjuvant chemotherapy for colorectal cancer and the main guidelines of adjuvant treatment.]

Lege Artis Medicinae


ÚJSZÁSZY László, SIMON László, HORVÁTH Gábor, TAM Beatrix

[The frequency of colorectal cancer is increasing all over the world. It is the second most frequent oncological disease leading to death in both sexes in Hungary. The main part of colorectal cancer develope after the age of 50. In case of patients having higher risk we have to calculate with the earlier appearance of the tumour and detectable molecular genetic disorders. The development of colorectal cancer needs a long time. Before the appearance of the cancer, precancerous processes (adenomas, polyps) can be detected in the large intestine. The development of colorectal cancer can be prevented by the removal of the adenomas (polypectomy). There are many different and efficient methods to detect the precancerous and early disorders. For increasing the compliance to screening programs the common efforts of the society, the National Health Care Services and medical doctors are necessary. The education of the population and the medical services would also be helpful. The colorectal cancer screening programs are costeffective and supported by the different health services independently from the type of the insurance. Screening the patients having higher risk is one of most important task. In these cases the use of colonoscopy is the most frequent method for the screening and follow up as well.]

Clinical Oncology

[How the molecular informations infl uence the therapeutic strategy against colorectal cancer?]

AXEL Grothey

[Colorectal cancer is not a homogenous disease, but it has different subgroups based on their molecular characteristics. NCCN and ESMO guidelines emphasize the importance of the determination of RAS and BRAF mutations in those patients who are intended to treat with targeted therapy. The increase in knowledge on the molecular changes will help to design and start a new generation of clinical trials, which will be designed not on their randomization of large groups of unselected patients, but rather on the consideration of the molecular subgroups determined before introducing therapy.]