Dietary vitamin D intake and serum 25-hydroxyvitamin D level in relation to disease outcomes in head and neck cancer patients

Season of radiotherapy and outcomes of head & neck cancer patients in the MACH-NC & MARCH meta-analyses

BACKGROUND

A single institution retrospective study suggested that head and neck squamous cell cancer (HNSCC) patients receiving radiotherapy (RT) during "dark" season (fall/winter) may have better outcomes than those treated during "light" season (spring/summer), possibly secondary to seasonal variations in cell cycle progression. We investigated the impact of season of RT in two large, multi-institutional, prospective datasets of randomized trials.

METHODS

Individual patient data from the MACH-NC and MARCH meta-analyses were analyzed. Dark season was defined as mid-radiotherapy date during fall or winter and light the reverse, using equinoxes to separate the two periods. Primary endpoint was progression-free survival (PFS) and secondary endpoint was locoregional failure (LRF). The effect of season was estimated with a Cox model stratified by trial and adjusted on sex, tumor site, stage, and treatment. Planned sensitivity analyses were performed on patients treated around solstices, who received "complete radiotherapy", patients treated with concomitant radio-chemotherapy and on trials performed in Northern countries.

RESULTS

11320 patients from 33 trials of MARCH and 6276 patients from 29 trials of MACH-NC were included. RT during dark season had no benefit on PFS in the MARCH (hazard ratio[HR]: 1.01 [95%CI 0.97;1.05],p=0.72) or MACH-NC dataset (HR:1.00 [95%CI 0.94;1.06],p=1.0. No difference in LRF was observed in the MARCH (HR:1.00 [95%CI 0.94;1.06,p=0.95) or MACH-NC dataset (HR:0.99 [95%CI 0.91; 1.07],p=0.77). Sensitivity analyses showed similar results.

CONCLUSION

Season of RT had no impact on PFS or LRF in two large databases of HNSCC.

The association between the Mediterranean Diet Score and death from cancer of the head and neck

PURPOSE

The association between diet quality, captured by the Mediterranean Diet Score (MDS), and mortality was studied among 1184 individuals diagnosed with head and neck cancer (HNC) who reflected on the year preceding diagnosis about their usual diet using National Cancer Institute's Diet History Questionnaire (DHQ).

METHODS

Intakes of nine dietary components were scored and summed to construct the MDS (sample: median = 4; range (0-9); lower MDS reflected poorer diet quality; 5-year survival probability = 0.62). Cox regression estimated 5-year hazard ratios (HR) and 95% confidence intervals (95CI) for all-cause mortality and for HNC-specific death for contrasts of MDS quintiles. Effect measure modification (EMM) by tumor features [human papillomavirus (HPV) positivity; anatomic site] and sociodemographic behavioral factors [race, body mass index (BMI), smoking, alcohol consumption] was explored.

RESULTS

The 5-year [HR (95CI); P-trend] for all-cause mortality and HNC-specific mortality for highest versus lowest MDS quintile contrasts were [0.51 (0.33, 0.80); 0.014] and [0.43 (0.22, 0.85); 0.004], respectively. A unit increase in MDS adherence resulted in a 15% reduction of the 5-year HR for HNC-specific death for tumors located at the oral cavity [HR (95CI): 0.85 (0.75, 0.96)]. Poor diet quality (MDS ≤ 4) interacted with lower BMI (kg/m2 < 25) and separately with ever-using alcohol to produce 5-year HRs for all-cause and HNC-specific mortality that were statistically significantly larger than the sum of the individual HRs representing each combination (Poor diet quality + lower BMI; Poor diet quality + ever-using alcohol).

CONCLUSION

Greater adherence to a Mediterranean diet pattern prior to HNC diagnosis may reduce post-diagnosis mortality.

Role of Vitamin D in Head and Neck Cancer-Immune Function, Anti-Tumour Effect, and Its Impact on Patient Prognosis

Head and neck squamous cell carcinoma (HNSCC) describes a heterogeneous group of human neoplasms of the head and neck with high rates of morbidity and mortality, constituting about 3% of all cancers and ~1.5% of all cancer deaths. HNSCC constituted the seventh most prevalent human malignancy and the most common human cancer in the world in 2020, according to multi-population observations conducted by the GLOBOCAN group. Since approximately 60-70% of patients present with stage III/IV neoplastic disease, HNSCC is still one of the leading causes of death in cancer patients worldwide, with an overall survival rate that is too low, not exceeding 40-60% of these patients. Despite the application of newer surgical techniques and the implementation of modern combined oncological treatment, the disease often follows a fatal course due to frequent nodal metastases and local neoplastic recurrences. The role of micronutrients in the initiation, development, and progression of HNSCC has been the subject of considerable research. Of particular interest has been vitamin D, the pleiotropic biologically active fat-soluble family of secosteroids (vitamin-D-like steroids), which constitutes a key regulator of bone, calcium, and phosphate homeostasis, as well as carcinogenesis and the further development of various neoplasms. Considerable evidence suggests that vitamin D plays a key role in cellular proliferation, angiogenesis, immunity, and cellular metabolism. A number of basic science, clinical, and epidemiological studies indicate that vitamin D has multidirectional biological effects and influences anti-cancer intracellular mechanisms and cancer risk, and that vitamin D dietary supplements have various prophylactic benefits. In the 20th century, it was reported that vitamin D may play various roles in the protection and regulation of normal cellular phenotypes and in cancer prevention and adjunctive therapy in various human neoplasms, including HNSCC, by regulating a number of intracellular mechanisms, including control of tumour cell expansion and differentiation, apoptosis, intercellular interactions, angio- and lymphogenesis, immune function, and tumour invasion. These regulatory properties mainly occur indirectly via epigenetic and transcriptional changes regulating the function of transcription factors, chromatin modifiers, non-coding RNA (ncRNAs), and microRNAs (miRs) through protein-protein interactions and signalling pathways. In this way, calcitriol enhances intercellular communication in cancer biology, restores the connection with the extracellular matrix, and promotes the epithelial phenotype; it thus counteracts the tumour-associated detachment from the extracellular matrix and inhibits the formation of metastases. Furthermore, the confirmation that the vitamin D receptor (VDR) is present in many human tissues confirmed the physiopathological significance of vitamin D in various human tumours. Recent studies indicate quantitative associations between exposure to vitamin D and the incidence of HNC, i.e., cancer risk assessment included circulating calcidiol plasma/serum concentrations, vitamin D intake, the presence of the VDR gene polymorphism, and genes involved in the vitamin D metabolism pathway. Moreover, the chemopreventive efficacy of vitamin D in precancerous lesions of the head and neck and their role as predictors of mortality, survival, and recurrence of head and neck cancer are also widely discussed. As such, it may be considered a promising potential anti-cancer agent for developing innovative methods of targeted therapy. The proposed review discusses in detail the mechanisms regulating the relationship between vitamin D and HNSCC. It also provides an overview of the current literature, including key opinion-forming systematic reviews as well as epidemiological, prospective, longitudinal, cross-sectional, and interventional studies based on in vitro and animal models of HNSCC, all of which are accessible via the PubMed/Medline/EMBASE/Cochrane Library databases. This article presents the data in line with increasing clinical credibility.

Association Between Vitamin D Exposure and Head and Neck Cancer: A Systematic Review With Meta-Analysis

Background

Vitamin D deficiency is a well-described preventable cause of many cancers; the association of vitamin D use with the development of head and neck cancer (HNC) is not clear. We aim to conduct a systematic review of the studies assessing the relation between vitamin D exposure and the prevention and prognosis of the HNC using meta-analysis.

Methods

PubMed, EMBASE, Cochrane Library, Web of Science up to 1 January 2021, and reference lists of related studies were searched. We extracted observational studies reporting the association between vitamin D (vitamin D receptor gene polymorphisms, 25-hydroxyvitamin D concentrations, and vitamin D intake) and the outcomes of interest (HNC incidence and HNC mortality) in HNC patients aged 18 or older. Fixed effects models were used to calculate pooled effect sizes and 95% confidence intervals (CIs) by RevMan (version 5.3).

Results

Sixteen studies with a total of 81,908 participants were enrolled in our meta-analysis. Based on the pooled genomic analysis, comparing with participants with the genotypes of Ff + FF or FF, the pooled odds ratio (OR) of participants with the genotype of ff was 0.77 (95% CI: 0.61 to 0.97) and 0.75 (0.58 to 0.97), respectively. A similar trend was noted when comparing tt with Tt + TT or TT, in which OR (95% CI) was 0.70 (0.55 to 0.90) and 0.72 (0.55 to 0.95). No significant association was identified between BsmI polymorphism and HNC. Furthermore, the OR of HNC incidence was 0.77 (0.65 to 0.92) for participants with vitamin D intake over the ones with a regular diet. High concentrations of circulated 25-hydroxyvitamin D (25-OHD) significantly decreased by 32% of HNC incidence (OR (95% CI): 0.68 (0.59 to 0.78)) and increased HNC survival (pooled hazard ratio 1.13, 1.05 to 1.22) during a 4-5 years follow-up. High concentrations of circulating 25-OHD in patients with HNC led to a decreased risk of mortality to 0.75 (0.60 to 0.94) as the follow-up extends to 8-12 years.

Conclusions

Elevated activities of vitamin D by diet intake, genomic polymorphisms, or circulated 25-OHD may protect people from HNC and improve the prognosis of patients with HNC.

Systematic Review Registration

PROSPERO, identifier CRD42020176002 (https://www.crd.york.ac.uk/PROSPERO/display_record.php?RecordID=176002).

Vitamin D in Head and Neck Cancer: a Systematic Review

PURPOSE OF REVIEW

Observational studies have shown that serum 25-OH vitamin D [25(OH)D] is inversely associated with overall cancer risk in many malignancies. We performed a systematic literature review to determine whether vitamin D deficiency is related to head and neck cancer (HNC) etiology and outcome.

RECENT FINDINGS

The search yielded five prospective studies reporting 25(OH)D levels prior to cancer diagnosis and their effect on the risk of HNC. Eight studies were cross-sectional or case-control studies, in which 25(OH)D levels were only measured after cancer diagnosis. Two studies found an inverse association between 25(OH)D level and HNC risk, while two other prospective cohort studies demonstrated no connection between 25(OH)D and HNC risk. Several studies reported cancer patients to have significantly lower 25(OH)D levels than controls. Associations between 25(OH)D and prognosis and mortality were variable. The link between vitamin D and HNC has so far only been investigated in a few observational, prospective, and case-control studies. Vitamin D deficiency may be more common in HNC patients than in the healthy population. There is no evidence for a causal relationship. Further studies are needed to evaluate whether low 25(OH)D concentrations play a role in the development or outcome of HNCs.

Vitamin D intake and survival and recurrence in head and neck cancer patients

OBJECTIVES/HYPOTHESIS

With an unacceptably low 5-year survival rate and few identified modifiable factors that affect head and neck cancer (HNC) outcomes, HNC survival remains an important public health problem. Vitamin D has been shown to be associated with immune reactivity and improved outcomes for some cancer sites, but findings are mixed, and few studies have examined vitamin D in relation to HNC. This study aimed to assess the association between vitamin D intake and survival outcomes in HNC patients.

STUDY DESIGN

Prospective cohort study.

METHODS

This study utilized data on 434 HNC patients with valid pretreatment food frequency questionnaire data who participated in the University of Michigan Head and Neck Specialized Program of Research Excellence epidemiology project. Cox proportional hazard models were used to estimate the associations between total, dietary, and supplemental vitamin D intake and HNC outcomes, while adjusting for other known prognostic factors.

RESULTS

After multivariable adjustment, we found a statistically significant inverse trend between total vitamin D intake and recurrence (Q4 vs. Q1 hazard ratio: 0.47, 95% confidence interval: 0.20-1.10, P trend = .048). We observed no association with dietary or supplemental intake separately, and no association was observed with all-cause or HNC-specific mortality.

CONCLUSIONS

These findings suggest that HNC patients with lower levels of vitamin D intake are at higher risk of recurrence. If borne out in future studies, our results suggest that increased vitamin D intake through dietary intervention or the use of supplements may be a feasible intervention for prevention of recurrence in HNC patients.

LEVEL OF EVIDENCE

2b. Laryngoscope, E371-E376, 2018.

The impact of vitamin D pathway genetic variation and circulating 25-hydroxyvitamin D on cancer outcome: systematic review and meta-analysis

BACKGROUND

Vitamin D has been linked with improved cancer outcome. This systematic review and meta-analysis investigates the relationship between cancer outcomes and both vitamin D-related genetic variation and circulating 25-hydroxyvitamin D (25OHD) concentration.

METHODS

A systematic review and meta-analysis of papers until November 2016 on PubMed, EMBASE and Web of Science pertaining to association between circulating vitamin D level, functionally relevant vitamin D receptor genetic variants and variants within vitamin D pathway genes and cancer survival or disease progression was performed.

RESULTS

A total of 44 165 cases from 64 studies were included in meta-analyses. Higher 25OHD was associated with better overall survival (hazard ratio (HR=0.74, 95% CI: 0.66-0.82) and progression-free survival (HR=0.84, 95% CI: 0.77-0.91). The rs1544410 (BsmI) variant was associated with overall survival (HR=1.40, 95% CI: 1.05-1.75) and rs7975232 (ApaI) with progression-free survival (HR=1.29, 95% CI: 1.02-1.56). The rs2228570 (FokI) variant was associated with overall survival in lung cancer patients (HR=1.29, 95% CI: 1.0-1.57), with a suggestive association across all cancers (HR=1.26, 95% CI: 0.96-1.56).

CONCLUSIONS

Higher 25OHD concentration is associated with better cancer outcome, and the observed association of functional variants in vitamin D pathway genes with outcome supports a causal link. This analysis provides powerful background rationale to instigate clinical trials to investigate the potential beneficial effect of vitamin D in the context of stratification by genotype.

In serum, higher parathyroid hormone but not lower vitamin D is associated with oral squamous cell carcinoma

INTRODUCTION

Vitamin D and calcium are known to regulate differentiation and proliferation of keratinocytes; they might potentially have a role in suppressing carcinogenesis in squamous epithelium. Serum parathyroid hormone (pth) is a sensitive indicator of calcium and vitamin D deficiency, and 25-hydroxyvitamin D [25(OH)D] is an established marker of vitamin D status.

METHODS

To determine whether levels of 25(OH)D, calcium, or pth in serum are associated with oral squamous cell carcinoma (oscc), we examined those parameters in serum collected from 70 patients with oscc and from an equal number of matched control subjects.

RESULTS

The results showed that intact pth was significantly higher in serum from oscc patients than in serum from control subjects. However, we observed no significant differences in 25(OH)D or calcium in serum from oscc patients and from control subjects.

CONCLUSIONS

We conclude that higher serum pth, but not lower serum vitamin D or calcium, is associated with oscc.

Vitamin D, Cancer Risk, and Mortality

Antiproliferative effects of 1,25-dihydroxyvitamin D, the biologically active form of vitamin D, are well established in various cell types by influencing cell differentiation and decreasing cell proliferation, growth, invasion, angiogenesis, and metastasis. Several meta-analyses showed that low serum levels of 25(OH)D was associated with colorectal cancer and overall mortality, while the association with cancer mortality was less consistent. VDR is a crucial mediator for the cellular effects of vitamin D and conflicting data have been reported for most malignancies. Beyond VDR, the biological effects of vitamin D are mediated by the vitamin D-binding protein. The GC (group-specific component) gene, encoding DBP, is highly polymorphic and several polymorphisms were investigated in association with cancer development with controversial results. Vitamin D supplementation was found to be associated with a reduced risk of overall mortality, reviewing all published trials on healthy subjects, whereas the evidence of an effect on cancer risk and mortality is less clear. Furthermore, long-term health effects of high doses of vitamin D, extended duration of supplementation, and the association with different baseline vitamin D levels remain to be investigated. In summary, epidemiological and preclinical studies support the development of vitamin D as preventative and therapeutic anticancer agents, with significant associations especially found for low vitamin D status with overall mortality and cancer outcome, more than cancer incidence. However, a definitive conclusion cannot be drawn and only large randomized clinical trials, both in healthy subjects and in cancer patients, will allow to draw definitive conclusions on the effect of vitamin D supplementation on cancer risk, prognosis, and mortality.

Review: the impacts of circulating 25-hydroxyvitamin D levels on cancer patient outcomes: a systematic review and meta-analysis

CONTEXT

Circulating levels of 25-hydroxyvitamin D [25(OH)D] may affect the prognosis of cancer patients; however, the epidemiological results are not consistent.

OBJECTIVE

To perform a meta-analysis of all published studies to assess the associations of circulating 25(OH)D levels measured at or near the time of diagnosis and outcomes for cancer patients.

DATA SOURCES

Searches of the PubMed and MEDLINE databases were performed and updated to December 2013.

STUDY SELECTION

Studies reporting an association between circulating 25(OH)D levels at or near the time of diagnosis and outcomes for the patients were included.

DATA EXTRACTION

Data extraction was performed independently by two authors, and conflicts were resolved by a third investigator.

DATA SYNTHESIS

Included in the meta-analysis were 25 studies with 17 332 cases. Significant associations between circulating 25(OH)D levels at or near the time of diagnosis and the outcomes for cancer patients were found. The pooled hazard ratio for the highest vs the lowest quartile of circulating 25(OH)D levels was 0.55 (95% confidence interval [CI] = 0.33-0.91) for overall survival of colorectal cancer patients, 0.63 (95% CI = 0.51-0.77) for breast cancer patients, and 0.48 (95% CI = 0.36-0.64) for lymphoma patients. Higher 25(OH)D levels were significantly associated with reduced cancer-specific mortality for patients with colorectal cancer (P = .005) and lymphoma (P < .001) and improved disease-free survival for patients with breast cancer (P < .001) or lymphoma (P < .05). A 10-nmol/L increment in circulating 25(OH)D levels conferred a hazard ratio of 0.96 (95% CI = 0.95-0.97) for overall survival of the cancer patients.

CONCLUSIONS

The results indicate that cancer patients with higher circulating 25(OH)D levels at or near the time of diagnosis have better outcomes.

Prospective population-based study of the association between serum 25-hydroxyvitamin-D levels and the incidence of specific types of cancer

BACKGROUND

Observational studies have suggested an inverse association between vitamin D status and cancer. We investigated the prospective associations between vitamin D status and the total and specific type of cancer in three cohorts from the general Danish population.

METHODS

A total of 12,204 individuals 18 to 71 years old were included. The level of 25-hydroxyvitamin D was measured at baseline, and information about cancer was obtained from the Danish Cancer Registry.

RESULTS

During the 11.3-year median follow-up time, there were 1,248 incident cancers. HRs [95% confidence intervals (CI)] per 10 nmol/L higher baseline vitamin D level were: for all cancers (HR = 1.02; 95% CI, 0.99-1.04), all cancers excluding non-melanoma skin cancer, NMSC (HR = 1.00; 95% CI, 0.97-1.03), head and neck cancer (HR = 0.97; 95% CI, 0.84-1.12), colorectal cancer (HR = 0.95; 95% CI, 0.88-1.02), cancer of bronchus and lung (HR = 0.98; 95% CI, 0.91-1.05), breast cancer (HR = 1.02; 95% CI, 0.96-1.09), cancer of the uterus (HR = 1.10; 95% CI, 0.95-1.27), prostate cancer (HR = 1.00; 95% CI, 0.93-1.08), cancer of the urinary organs (HR = 1.01; 95% CI, 0.90-1.14), NMSC (HR = 1.06; 95% CI, 1.02-1.10), and malignant melanoma (HR = 1.06; 95% CI, 0.95-1.17).

CONCLUSIONS

Apart from a significantly higher risk for NMSC with higher vitamin D status, we found no statistically significant associations between vitamin D status and total or specific cancers.

IMPACT

Our results do not indicate that there is an impact of vitamin D on total cancer incidence.

Vitamin D and risk of cause specific death: systematic review and meta-analysis of observational cohort and randomised intervention studies

OBJECTIVE

To evaluate the extent to which circulating biomarker and supplements of vitamin D are associated with mortality from cardiovascular, cancer, or other conditions, under various circumstances.

DESIGN

Systematic review and meta-analysis of observational studies and randomised controlled trials.

DATA SOURCES

Medline, Embase, Cochrane Library, and reference lists of relevant studies to August 2013; correspondance with investigators.

STUDY SELECTION

Observational cohort studies and randomised controlled trials in adults, which reported associations between vitamin D (measured as circulating 25-hydroxyvitamin D concentration or vitamin D supplement given singly) and cause specific mortality outcomes.

DATA EXTRACTION

Data were extracted by two independent investigators, and a consensus was reached with involvement of a third. Study specific relative risks from 73 cohort studies (849,412 participants) and 22 randomised controlled trials (vitamin D given alone versus placebo or no treatment; 30,716 participants) were meta-analysed using random effects models and were grouped by study and population characteristics.

RESULTS

In the primary prevention observational studies, comparing bottom versus top thirds of baseline circulating 25-hydroxyvitamin D distribution, pooled relative risks were 1.35 (95% confidence interval 1.13 to 1.61) for death from cardiovascular disease, 1.14 (1.01 to 1.29) for death from cancer, 1.30 (1.07 to 1.59) for non-vascular, non-cancer death, and 1.35 (1.22 to 1.49) for all cause mortality. Subgroup analyses in the observational studies indicated that risk of mortality was significantly higher in studies with lower baseline use of vitamin D supplements. In randomised controlled trials, relative risks for all cause mortality were 0.89 (0.80 to 0.99) for vitamin D3 supplementation and 1.04 (0.97 to 1.11) for vitamin D2 supplementation. The effects observed for vitamin D3 supplementation remained unchanged when grouped by various characteristics. However, for vitamin D2 supplementation, increased risks of mortality were observed in studies with lower intervention doses and shorter average intervention periods.

CONCLUSIONS

Evidence from observational studies indicates inverse associations of circulating 25-hydroxyvitamin D with risks of death due to cardiovascular disease, cancer, and other causes. Supplementation with vitamin D3 significantly reduces overall mortality among older adults; however, before any widespread supplementation, further investigations will be required to establish the optimal dose and duration and whether vitamin D3 and D2 have different effects on mortality risk.

The Inverse Relationship between 25-Hydroxyvitamin D and Cancer Survival: Discussion of Causation

Cancer mortality rates vary inversely with geographic latitude and solar ultraviolet-B doses. This relationship may be due to an inhibitory role of vitamin D on cancer development. The relationship between vitamin D and cancer appears to be stronger for studies of cancer mortality than incidence. Because cancer mortality reflects both cancer incidence and survival, the difference may be due to effects of vitamin D on cancer survival. Here we review analytic epidemiologic studies investigating the relation between vitamin D, measured by circulating levels of 25-hydroxyvitamin D (25-OHD), and cancer survival. A relationship between low 25-OHD levels and poor survival is shown by most of the reviewed studies. This relationship is likely to be causal when viewed in light of most criteria for assessing causality (temporality, strength, exposure-response, biological plausibility and consistency). A serum level of 25-OHD around 50 nmol/L appears to be a threshold level. Conversely, there are several mechanisms whereby cancer could lower serum levels of 25-OHD. The severity of disease at the time of diagnosis and time of serum sampling are key factors to clarify the temporal aspect of these relationships. Evidence that vitamin D supplementation could retard the disease process or prolong survival time would be key evidence, but is difficult to generate. However, recent clinical trial results in prostate cancer support a role for vitamin D in this regard.

Postdiagnosis supplement use and breast cancer prognosis in the After Breast Cancer Pooling Project

Vitamin supplement use after breast cancer diagnosis is common, but little is known about long-term effects on recurrence and survival. We examined postdiagnosis supplement use and risk of death or recurrence in the After Breast Cancer Pooling Project, a consortium of four cohorts of 12,019 breast cancer survivors from the United States and China. Post-treatment supplement use (vitamins A, B, C, D, E, and multivitamins) was assessed 1-5 years postdiagnosis. Associations with risk of recurrence, breast cancer-specific mortality, or total mortality were analyzed in Cox proportional hazards models separately by cohort. Individual cohort results were combined using random effects meta-analysis. Interactions with smoking, treatment, and hormonal status were examined. In multivariate models, vitamin E was associated with a decreased risk of recurrence (RR: 0.88; 95 % CI 0.79-0.99), and vitamin C with decreased risk of death (RR: 0.81; 95 % CI 0.72-0.92). However, when supplements were mutually adjusted, all associations were attenuated. There were no statistically significant associations with breast cancer mortality. The use of antioxidant supplements (multivitamins, vitamin C, or E) was not associated with recurrence, but was associated with a 16 % decreased risk of death (95 % CI 0.72-0.99). In addition, vitamin D was associated with decreased risk of recurrence among ER positive, but not ER negative tumors (p-interaction = 0.01). In this large consortium of breast cancer survivors, post-treatment use of vitamin supplements was not associated with increased risk of recurrence or death. Post-treatment use of antioxidant supplements was associated with improved survival, but the associations with individual supplement were difficult to determine. Stratification by ER status and considering antioxidants as a group may be more clinically relevant when evaluating associations with cancer risk and mortality.

Relationship between cancer survival and ambient ultraviolet B irradiance in China

BACKGROUND

Ecological studies in predominantly European populations have reported higher cancer survival in areas of higher solar ultraviolet (UV) B irradiation, perhaps due to a cancer protective effect of vitamin D synthesized photochemically in the skin. Such studies have not been done in developing countries, perhaps because of lack of cancer registries that can do outcome follow-up. One minus the mortality-to-incidence ratio (1-MIR), however, can be used as a measure of survival, and MIR as a measure of fatality, in developing country cancer registries. We analyzed the association between ambient solar UVB and MIR in China.

METHODS

National cancer registration data in 32 counties of China in 2004-2005 were used to estimate MIR by age, sex, and area. The accuracy of 1-MIR as a measure of survival was assessed in the Cixian County cancer registry. Contemporary satellite measurements of cloud-adjusted ambient UVB intensity at 305 nm were taken from an NASA database and spatial Kriging methods used to estimate the average daily irradiance in each county. We estimated mortality hazard ratios (HRs) per 10 mW/m(2) of UVB for all cancers together, and the ten commonest cancer types by fitting a generalized linear model assuming mortality had a binomial distribution conditional on the sum of mortality and incidence, adjusted for sex, age, and location.

RESULTS

The 5-year survival proportions for the main cancer types were in good agreement with 1-MIR in Cixian County. MIR ratios for all cancers combined were inversely associated with ambient UVB in men (HR = 0.96, 95% CI 0.93-0.99) and women (HR = 0.91, 95% CI 0.88-0.94) and in urban (HR = 0.95, 95% CI 0.94-0.96) and rural areas (HR = 0.90, 95% CI 0.87-0.93). Similar inverse associations were present for cancers of esophagus, stomach, and bladder in both sexes together and breast cancer in women. They were present in urban residents for all major cancers except liver cancer, bladder cancer, and breast cancer in women. For rural residents, most HRs were <1.0 but, with the exception of breast cancer, their upper 95% confidence bounds were >1.0.

CONCLUSION

Ambient UVB was significantly inversely associated with MIR for all cancers together and four of ten cancer types. Solar UVB may increase survival from some cancers in China.

What you and your patients need to know about vitamin D

"Vitamin D" is the term commonly used to denote the lipid-soluble hormone critical for calcium homeostasis and skeletal maintenance. A precursor to the active compound is found in many plants and animal tissues and can be absorbed from the gut; it can also be derived from cell membranes in the epidermis during ultraviolet B irradiation. This compound is then hydroxylated sequentially in the liver and kidney to produce the active hormone 1,25(OH)(2)D that binds its nuclear receptor to modulate gene expression. Recently, vitamin D hydroxylases and the nuclear receptor have been identified in many tissues, suggesting previously unrecognized roles for vitamin D. Some epidemiologic studies have also correlated low levels of the inactive storage form 25(OH)D with an increased incidence or prevalence of a variety of diseases, suggesting that large oral supplements and/or increased ultraviolet (UV) exposure might therefore improve individual health. However, randomized, prospective controlled trials comparing vitamin D supplements with placebo have not supported this belief. Moreover, current evidence supports the conclusion that protection from UV radiation does not compromise vitamin D status or lead to iatrogenic disease. In contrast, high vitamin D levels appear to incur a risk of kidney stones and other adverse effects. In the case of true vitamin D deficiency, supplements are a more reliable and quantifiable source of the vitamin than UV exposure.

Pretreatment dietary patterns, weight status, and head and neck squamous cell carcinoma prognosis

BACKGROUND

Few studies have evaluated the association of diet and weight status with head and neck cancer outcomes.

OBJECTIVE

The purpose of this study was to determine whether pretreatment dietary patterns and weight status are associated with head and neck cancer prognosis.

DESIGN

This was a longitudinal study of 542 patients with newly diagnosed head and neck cancer who completed food-frequency questionnaires and health surveys before treatment. Clinical data were abstracted from medical records and the Social Security Death Index. Dietary patterns were identified by using principal component analysis. Cox proportional hazard models were used to examine the association of derived dietary patterns (fit by quintiles of exposure) and weight status with time to recurrence and survival, with control for covariates.

RESULTS

During the study period, there were 229 deaths and 184 recurrences. Two dietary patterns were identified: a whole-foods pattern (characterized by high intakes of vegetables, fruit, fish, poultry, and whole grains) and a Western pattern (characterized by high intakes of red and processed meats, refined grains, potatoes, and French fries). In multivariable analyses, significantly fewer deaths were observed in subjects most adherent to the whole-foods pattern (HR: 0.56; 95% CI: 0.34, 0.92; P-trend = 0.01). Subjects classified as overweight or obese had significantly fewer deaths (HR: 0.65; 95% CI: 0.49, 0.85; P = 0.001) and recurrences (HR: 0.70; 95% CI: 0.52, 0.95; P = 0.02) than did normal-weight or underweight subjects.

CONCLUSION

Consumption of a diet rich in vegetables, fruit, fish, poultry, and whole grains and being overweight before diagnosis with head and neck cancer are associated with a better prognosis.

Genetic sequence variants in vitamin D metabolism pathway genes, serum vitamin D level and outcome in head and neck cancer patients

Although some studies have reported associations between serum vitamin D level and prognosis in several cancers, others have found associations between genetic sequence variants (GSVs) in the vitamin D metabolism pathway genes and outcomes in various cancers including head and neck cancer (HNC). We comprehensively evaluated the association and interaction of GSVs in vitamin D metabolism pathway genes and their regulatory effects on circulatory serum vitamin D level in HNC outcome. We systemically evaluated the association of 89 tagging and candidate-based GSVs in six major vitamin D metabolism pathway genes (VDR, GC, CYP24A1, CYP27A1, CYP27B1 and CYP2R1) and the circulating serum vitamin D level with overall survival (OS) and second primary cancer (SPC) in 522 Stages I-II radiation-treated patients with HNC. For OS: median follow-up time was 8 years; for SPC, 4.4 years. The most common subsite was the larynx (84%). Three hundred and twelve patients were alive at the end of follow-up for OS. SPCs were diagnosed in 108 patients and were primarily of lung (46%). Serum vitamin D levels were significantly lower in patients carrying the minor alleles of GC:rs4588 and CYP2R1:rs10500804. CYP24A1:rs2296241 was significantly associated with OS and CYP2R1:rs1993116 was with SPC. These two GSVs remained significantly associated after adjusting for serum vitamin D level and important clinical factors. GSVs in the vitamin D metabolism pathway genes were associated with disease outcomes in HNC patients; however, these GSVs are different from those affecting serum vitamin D levels.

Vitamin D and overall mortality

Vitamin D is a steroid molecule, mainly produced in the skin that regulates the expression of a large number of genes. Several meta-analyses of epidemiological studies support the evidence that low vitamin D serum level, which is highly prevalent worldwide, could be a 'new' risk factor for many chronic diseases including cancer, and for all-cause mortality. A meta-analysis in healthy subjects suggested that current doses of vitamin D supplements could be associated with decrease in total mortality rates. However, these associations are insufficient to establish causality between vitamin D and all-cause mortality. Furthermore, long-term health effects of high doses of vitamin D, that is, prolonged supplementation and association with different baseline vitamin D levels, remain to be investigated. Several trials are ongoing but population-based, placebo-controlled randomized trials with total mortality as the main endpoint should be planned to confirm a real beneficial effect of vitamin D for non-skeletal diseases and to prove causality.

Serum 25-hydroxyvitamin D and risk of oropharynx and larynx cancers in Finnish men

BACKGROUND

Published studies suggesting a relationship between vitamin D and some common cancers sparked interest in the association of vitamin D with head and neck cancers. Prolonged darker months in Finland are associated with lower levels of ultraviolet B radiation, raising concerns about low vitamin D levels.

METHODS

We used a nested case--control study in the prospective Alpha-Tocopherol Beta Carotene (ATBC) Study of male smokers in Finland, to examine the relationship between serum 25(OH)D and risk of developing squamous cancers of the head and neck. Using conditional logistic regression, we calculated the multivariate adjusted ORs and CIs comparing those with serum 25(OH)D adequate levels of 50 to <75 nmol/L to those <25.0.

RESULTS

We identified incident cancers of the oral cavity (n = 134), pharynx (n = 48), and larynx (n = 158). Median serum vitamin D was 31 nmol/L (interquartile range: 21-48), which is below the 50 nmol/L cutoff point was considered adequate for bone and overall health. Comparing those with serum 25(OH)D below 25 nmol/L to those 50 to <75 nmol/L as the referent, the OR was 1.35 (95% CI: 0.53-3.43, P(trend) = 0.65) for overall head and neck cancers. Stratification by cancer subsites of the oral cavity, pharynx, and larynx (P(trend) = 0.93, 0.78, 0.26, respectively) or by season of blood draw also showed no association.

CONCLUSIONS

Our study showed no association between serum 25(OH)D and risk of head and neck cancers.

IMPACT

This study does not support the hypothesis that greater vitamin D exposure would reduce the risk of developing head and neck squamous cancers.