Incidence and spectrum of dialysis-associated cancer in three continents

Impact of dialysis on intravesical recurrence and survival outcomes in upper tract urothelial cancer patients undergoing radical nephroureterectomy

BACKGROUND

Upper tract urothelial carcinoma (UTUC) presents a significant recurrence risk following radical nephroureterectomy (RNU). Patients on dialysis may experience unique clinical trajectories due to uremic states and altered immune responses.

OBJECTIVE

To evaluate the impact of dialysis on intravesical recurrence and survival outcomes in patients with UTUC undergoing RNU, and to identify predictive factors influencing prognosis.

METHODS

A retrospective cohort study analyzed 402 patients with non-metastatic UTUC treated with RNU between 2001 and 2014. Patients were stratified into dialysis (n = 66) and non-dialysis (n = 336) groups. Survival and recurrence outcomes were assessed using Kaplan-Meier and Cox regression analyses.

RESULTS

Dialysis patients were predominantly female, younger, and exhibited less advanced pathological tumor stages. Dialysis was associated with higher intravesical recurrence rates (p = 0.009), which were largely attributable to a history of bladder cancer (42.4% vs. 26.5%; p = 0.009). After adjustment for bladder cancer history, dialysis was not an independent predictor of bladder recurrence-free survival (BRFS). Advanced pT stages (HR: 3.9, p = 0.012) and prior bladder cancer were the primary factors influencing BRFS.

CONCLUSIONS

Dialysis does not independently worsen surgical outcomes or BRFS in UTUC patients post-RNU when accounting for prior bladder cancer. Prognostic models should integrate these findings to enhance individualized surveillance and treatment strategies.

Is End-Stage Renal Disease Tumor Suppressive? Dispelling the Myths

The prevalence of end-stage renal disease is increasing worldwide. Malignancies accompanying end-stage renal disease are detected in approximately 120 individuals per 10,000 person-years. Most studies have suggested that end-stage renal disease causes carcinogenesis and promotes tumor development; however, this theory remains questionable. Contrary to the theory that end-stage renal disease is predominantly carcinogenic, recent findings have suggested that after controlling for biases and sampling errors, the overall cancer risk in patients with end-stage renal disease might be lower than that in the general population, except for renal and urothelial cancer risks. Additionally, mortality rates associated with most cancers are lower in patients with end-stage renal disease than in the general population. Several biological mechanisms have been proposed to explain the anticancer effects of end-stage renal disease, including premature aging and senescence, enhanced cancer immunity, uremic tumoricidal effects, hormonal and metabolic changes, and dialysis therapy-related factors. Despite common beliefs that end-stage renal disease exacerbates cancer risk, emerging evidence suggests potential tumor-suppressive effects. This review highlights the potential anticancer effects of end-stage renal disease, proposing reconsideration of the hypothesis that end-stage renal disease promotes cancer development and progression.

Stage at Diagnosis and Prognosis of Colorectal, Stomach, Lung, Liver, Kidney, and Bladder Cancers in Dialysis Patients: A Multicenter Retrospective Study Using Cancer Registry Data and Administrative Data

<b><i>Background:</i></b> Cancer is an important comorbidity that can affect survival in dialysis patients. However, it is unclear if dialysis patients who develop cancer are disadvantaged by later detection and poorer prognosis. This study comparatively examined the stage at diagnosis and prognosis of several common cancer types in dialysis and nondialysis patients. <b><i>Methods:</i></b> In this retrospective cohort study, cancer registry data were linked with administrative data to identify dialysis and nondialysis patients with any new diagnosis of cancer between 2010 and 2015 at 36 hospitals in Osaka Prefecture, Japan. In these patients, we identified the cancer stage at diagnosis for patients with colorectal, stomach, lung, liver, kidney, and bladder cancers. The association between dialysis and survival time (up to 3 years of follow-up) was examined for each cancer type using Cox proportional hazards models that adjusted for age, sex, and cancer stage. <b><i>Results:</i></b> We analyzed 2,161 dialysis patients and 158,964 nondialysis patients with cancer. Dialysis patients had a higher prevalence of colorectal, liver, and kidney cancers than nondialysis patients. Colorectal, stomach, lung, liver, and kidney cancers were diagnosed earlier in dialysis patients, whereas bladder cancer was diagnosed at an advanced stage. The Cox proportional hazards models revealed that mortality was significantly higher in dialysis patients with colorectal, stomach, lung, and bladder cancers than in nondialysis patients (all <i>p</i> &#x3c; 0.05). <b><i>Conclusions:</i></b> Dialysis patients had higher mortality for several common cancers despite their earlier detection. This poorer prognosis may be influenced by the unavailability and complications of cancer treatment for these patients.

Outcome of renal cell carcinoma in patients on dialysis compared to non-dialysis patients

PURPOSE

To investigate the impact of hemodialysis on survival in renal cell carcinoma (RCC) patients.

METHODS

We studied 388 patients who underwent radical or partial nephrectomy for RCC at Toranomon Hospital from 2005 to 2013. Survival curves were drawn according to the Kaplan-Meier method and compared with the log-rank test. Multivariate analysis was performed using the Cox proportional hazards regression model to assess the prognostic influence of hemodialysis on cancer-specific survival.

RESULT

Of the 388 patients, 66 were on hemodialysis and 322 were not on dialysis. In the hemodialysis patients, incidental diagnosis of RCC was less frequent than in the non-dialysis patients. In addition, RCC was more likely to be multicentric (41% vs 1.2%), bilateral (14% vs 0.6%), and papillary (18% vs 7%) in hemodialysis patients. Moreover, tumors were smaller, the stage was lower, and the Fuhrman nuclear grade was higher in the patients on hemodialysis. The 5-year cancer-specific survival rate was 82.8% for hemodialysis patients and 93.5% for nondialysis patients. Multivariate analysis indicated that hemodialysis, stage, and Fuhrman nuclear grade were independent prognostic factors for RCC.

CONCLUSIONS

This study suggested that hemodialysis was an independent prognostic factor for cancer-specific survival in RCC patients, along with the tumor stage and Fuhrman nuclear grade.

Increased cancer risk in patients undergoing dialysis: a population-based cohort study in North-Eastern Italy

BACKGROUND

In southern Europe, the risk of cancer in patients with end-stage kidney disease receiving dialysis has not been well quantified. The aim of this study was to assess the overall pattern of risk for de novo malignancies (DNMs) among dialysis patients in the Friuli Venezia Giulia region, north-eastern Italy.

METHODS

A population-based cohort study among 3407 dialysis patients was conducted through a record linkage between local healthcare databases and the cancer registry (1998-2013). Person-years (PYs) were calculated from 30 days after the date of first dialysis to the date of DNM diagnosis, kidney transplant, death, last follow-up or December 31, 2013, whichever came first. The risk of DNM, as compared to the general population, was estimated using standardized incidence ratios (SIRs) and 95% confidence intervals (CIs).

RESULTS

During 10,798 PYs, 357 DNMs were diagnosed in 330 dialysis patients. A higher than expected risk of 1.3-fold was found for all DNMs combined (95% CI: 1.15-1.43). The risk was particularly high in younger dialysis patients (SIR = 1.88, 95% CI: 1.42-2.45 for age 40-59 years), and it decreased with age. Moreover, significantly increased DNM risks emerged during the first 3 years since dialysis initiation, especially within the first year (SIR = 8.52, 95% CI: 6.89-10.41). Elevated excess risks were observed for kidney (SIR = 3.18; 95% CI: 2.06-4.69), skin non-melanoma (SIR = 1.81, 95% CI: 1.46-2.22), oral cavity (SIR = 2.42, 95% CI: 1.36-4.00), and Kaposi's sarcoma (SIR = 10.29, 95% CI: 1.25-37.16).

CONCLUSIONS

The elevated risk for DNM herein documented suggest the need to implement a targeted approach to cancer prevention and control in dialysis patients.

The incidence of urinary tract cancers is related to preserved diuresis: a single-center report

PURPOSE

Residual diuresis progressively decreases with longer dialysis vintage, and higher incidence of renal and urinary tract cancers was often observed in hemodialyzed patients compared to the general population so we hypothesized that patients without preserved residual diuresis have higher risk of renal and urinary tract cancers than patients with preserved residual diuresis.

METHODS

Retrospective clinical data and pathology reports were completed for 307 uremic patients undergoing chronic hemodialysis. Patients were divided into two subgroups regarding residual diuresis: the first group with residual diuresis < 500 mL, 133 of 173 (76.8%) patients from this group were completely anuric, and the second group with 134 patients with residual diuresis > 500 mL.

RESULTS

Site- and type-specific cancers in our population of ESRD patients were all localized in estrogen-positive receptor organs. The increased risk of all types of urinary tract cancers occurred in the whole group, men and women, when compared to general population. There were a significantly higher number of patients with all types of cancers in the group with residual diuresis < 250 mL compared to patients with residual diuresis > 500 mL. Importantly, all urinary tract cancers were present in patients with residual diuresis < 500 mL.

CONCLUSION

Higher incidence of urinary tract cancers found in ESRD patients undergoing chronic hemodialysis is associated with lost residual diuresis. Residual diuresis in these patients might be considered a risk marker for future urinary tract cancers as well as already established markers.

Doxycycline treatment in dialysis related amyloidosis: discrepancy between antalgic effect and inflammation, studied with FDG-positron emission tomography: a case report

Background

No effective treatment is currently available and dialysis related amyloidosis continues to be invalidating in long-term dialysis patients. A recent case series reported reduction of osteoarticular pain on doxycycline treatment, extending the indications of this drug, used in other uncommon forms of amyloidosis, to dialysis patients. Explanations of the antalgic effect were the anti-inflammatory properties and anti-coiling effects of tetracycline.

Case presentation

Our report regards a 54-year-old woman, who was never transplanted and has been on hemodialysis and hemodiafiltration for overall 37 years, due to renal hypoplasia. In spite of high efficiency hemodiafiltration, she complained of increasing, invalidating osteoarticular pain; history and imaging suggested beta-2 microglobulin amyloid. Positron emission tomography (PET scan) identified metabolically active lesions in the involved settings. Low-dose doxycycline (100 mg/day) was started, leading to a considerable decrease in pain (over 6 months, from 7 to 8 to 4–5 on a 0–10 scale). At 6 months, a PET scan showed unmodified or increased uptake in the involved settings.

Conclusions

In summary, the previously described antalgic effect of doxycycline in dialysis related amyloidosis is confirmed in our case, the first studied using PET scan. The pattern at PET can suggests that the antalgic effect is independent from inflammation and points to other factors, such as interaction with fibril geometry or with bone structure.

Cancer risk in patients receiving renal replacement therapy: A meta-analysis of cohort studies

It has been reported that patients receiving renal replacement therapy (RRT), including dialysis and kidney transplantation, tend to have an increased risk of cancer; however, studies on the degree of this risk have remained inconclusive. The present meta-analysis was therefore performed to quantify the cancer risk in patients with RRT. Cohort studies assessing overall cancer risk in RRT patients published before May 29, 2015 were included following systematic searches with of PubMed, EMBASE and the reference lists of the studies retrieved. Random-effects meta-analyses were used to pool standardized incidence rates (SIRs) with 95% confidence intervals (CIs). Heterogeneity tests, sensitivity analyses and publication bias assessment were performed. A total of 18 studies including 22 cohort studies were eventually identified, which comprised a total of 1,528,719 patients. In comparison with the general population, the pooled SIR for patients with dialysis including non-melanoma skin cancer (NMSC), dialysis excluding NMSC, transplantation including NMSC, transplantation excluding NMSC and RRT were 1.40 (95% CI, 1.36-1.45), 1.35 (95% CI, 1.23-1.50), 3.26 (95% CI, 2.29-4.63), 2.08 (95% CI, 1.73-2.50) and 2.01 (95% CI, 1.70-2.38), respectively. The cancer risk was particularly high in subgroups of large sample size trials, female patients, younger patients (age at first dialysis, 0-34 years; age at transplantation, 0-20 years), the first year of RRT and non-Asian transplant patients. A significant association was also found between RRT and the majority of organ-specific cancers. However, neither dialysis nor transplantation was associated with breast, body of uterus, colorectal or prostate cancer. Significant heterogeneity was found regarding the association between RRT and overall cancer as well as the majority of site-specific cancer types. However, this heterogeneity had no substantial influence on the pooled SIR for overall cancer in RRT according to the sensitivity analysis. Compared with the general population, RRT patients have a significantly increased risk of overall cancer and the majority of specific cancer types, particularly Kaposi sarcoma (KS), lip cancer and NMSC in patients subjected to kidney transplantation and cancer of the thyroid gland and kidney as well as myeloma in dialysis patients. Considering the high heterogeneity encountered, further high-quality studies are required.

Shorter hemodialysis duration is a risk factor for the recurrence of urothelial carcinoma of the bladder in patients on maintenance hemodialysis

PURPOSE

To investigate the association of hemodialysis duration with the recurrence of urothelial carcinoma (UC) of the bladder and overall survival in patients undergoing maintenance hemodialysis (MHD).

PATIENTS AND METHODS

52 bladder cancer patients who underwent MHD at the Xiangya Hospital of The Central South University between 2001 and 2011 were enrolled in the study. The patients were divided into three groups according to hemodialysis duration, and patient mortality and tumor recurrence rates were analyzed. The association of hemodialysis duration with occurrence and recurrence of UC of the bladder was analyzed by Cox regression analysis. Survival was evaluated by the Kaplan-Meier method.

RESULTS

Out of 6266 chronic hemodialysis patients, 52 patients had UC of the bladder after the initiation of hemodialysis for 6 months. The mean age at hemodialysis onset was 55 years (IQR 36, 71). The major complaints were painless gross hematuria and urethral bloody discharge. Tumors were generally large and multifocal. The standardized incidence ratio of UC of the bladder was 43.9 compared with general population, and it was higher in women (76.7) and in the age group 61-65 years (186.6). The mean hemodialysis duration before the diagnosis of bladder cancer was 32 months. 30 (57.7 %) patients received hemodialysis no more than 3 years, 10 (19.2 %) patients received hemodialysis between 3 and 6 years, and 12 (23.1 %) patients received hemodialysis for more than 6 years.

CONCLUSION

Preoperative shorter hemodialysis duration is a risk factor for the occurrence and recurrence of UC of the bladder in patients undergoing MHD.

Cancer Among End-Stage Renal Disease Patients on Dialysis

Introduction: The aim of this study is to investigate the risk of cancer among end-stage renal disease (ESRD) patients on dialysis in Singapore. Materials and Methods: The study looks at a retrospective cohort of 5505 ESRD patients who had received dialysis between 1998 and 2007. The cancer risk of these patients would be compared against the risk of the general population. Results: During a median follow-up time of 3.9 years, 267 (4.9%) dialysis patients developed cancer. The risk of cancer (excluding non-melanoma skin cancer) is 1.66 times higher in dialysis patients than the general population, and is highest at age less than 35 years old and at first year after dialysis. Cancer risk was found to be significantly higher among Chinese dialysis patients, followed by Malays, compared to the general population. The 3 sites with highest elevated cancer risks among dialysis patients compared to the general population are kidney, tongue and multiple myeloma. Conclusion: The finding of elevated cancer risk among younger dialysis patients is similar to other international studies. High cancer risks among specific cancer sites were also consistent with other studies. In view of the lack of screening procedures for these cancers and shortened expected survival of ESRD patients, cancer screening of ESRD patients should be individualised and based on a reasonable life expectancy and transplant candidacy, keeping in mind the competing risk of cardiovascular mortality. Key words: Chronic dialysis, Chronic kidney disease, Malignant neoplasms

The association between chronic renal failure and renal cell carcinoma may differ between black and white Americans

PURPOSE

In the United States, renal cell carcinoma (RCC) incidence is higher among blacks than among whites. Risk of RCC is elevated among end-stage renal disease patients, although no studies have looked at differences by race in the relationship between chronic renal failure and RCC.

METHODS

We investigated RCC risk in relation to chronic renal failure in a population-based case-control study of blacks and whites in Chicago and Detroit. Data, including information on kidney disease, were collected from interviews with 1,217 RCC cases (361 blacks, 856 whites) and 1,235 controls (523 blacks, 712 whites). Odds ratios (OR) and 95 % confidence intervals (CI) were estimated using unconditional logistic regression.

RESULTS

Risk of RCC was increased in relation to chronic renal failure (OR 4.7, 95 % CI 2.2-10.1) and dialysis (OR 18.0, 95 % CI 3.6-91). The association remained after defining exposure as those who had chronic renal failure ≥10 years prior to RCC diagnosis. Chronic renal failure was more strongly associated with RCC among blacks than among whites (OR 8.7, 95 % CI 3.3-22.9 and 2.0, 0.7-5.6, respectively; p (interaction) = 0.03) and among those without a history of diabetes relative to diabetic subjects (OR 8.3, 95 % CI 3.1-22.7 and 1.9, 0.6-5.9, respectively; p (interaction) = 0.03).

CONCLUSIONS

These results suggest that chronic renal failure is a strong risk factor for RCC, particularly among black and non-diabetic subjects. Our findings of differences in risk estimates by race, to our knowledge the first such report, require replication.

Increased risk of cancer in chronic dialysis patients: a population-based cohort study in Taiwan

BACKGROUND

An increased incidence of cancer in chronic dialysis patients has not been confirmed in the Chinese population. The aim of this population-based study was to examine the risk of various types of cancers in chronic dialysis patients in Taiwan.

METHODS

Data of 92 348 chronic dialysis patients extracted from the National Health Institutes Research Database during 1997-2008 were analyzed. Patients newly diagnosed with end-stage renal disease, free of cancer and receiving dialysis for >3 months were eligible for inclusion in the study.

RESULTS

After a mean follow-up of 4.4 years, a new cancer was diagnosed in 4328 chronic dialysis patients. The standardized incidence ratio (SIR) of chronic dialysis patients was 1.4 [95% confidence interval (CI): 1.3-1.4] and annual incidence of cancer was 1.1%. A trend of an increased SIR of cancer was observed in young patients and within the first year of dialysis. Bladder cancer carried the highest SIR (SIR: 8.2, 95% CI: 6.7-9.9) and had the highest frequency (21.2%). Importantly, the frequency (15.3%) of liver cancer was the second highest and the SIR (SIR: 1.4, 95% CI: 1.2-1.5) of liver cancer in chronic dialysis patients was higher than that of their healthy counterparts. Unexpectedly, chronic dialysis patients had a significantly reduced risk of developing lung cancer.

CONCLUSION

Increased risk of cancer in chronic dialysis patients is confirmed in the Taiwanese population and it is necessary to develop different strategies for cancer screening in chronic dialysis patients among different ethnicities.

The pattern of excess cancer in dialysis and transplantation

BACKGROUND

After transplantation, cancer risk varies from no increase for several common cancers to a many-fold increase for a number of, chiefly virus-associated, cancers. The smaller excess of cancer in dialysis has been less well described, but two studies suggested that impaired immunity might be responsible.

METHODS

In a population-based cohort study of 28 855 patients who received renal replacement therapy (RRT), we categorized incident cancers as end-stage kidney disease (ESKD) related, immune deficiency related, not related to immune deficiency, or of uncertain status, according to whether they were, or were not, increased in published reports of cancer in ESKD prior to starting RRT, organ transplantation or human immunodeficiency virus infection. Standardized incidence ratios for, and excess burdens of, cancer were calculated for all persons normally resident in Australia starting treatment by dialysis or renal transplantation from 1982 to 2003.

RESULTS

The risk for ESKD-related cancers was increased 4-fold in dialysis and during transplant function. For immune deficiency-related cancers, the increase was 1.5 (95% CI 1.3-1.6) times in dialysis, and 5-fold after transplantation. ESKD- or immune deficiency-related cancers contributed to approximately 90% of the excess burden of cancer, 48% and 36%, respectively, in dialysis, and 10% and 78% after transplantation. The remaining excess malignancy was contributed by cancers whose relationship with ESKD and immune deficiency is not yet certain.

CONCLUSIONS

In RRT, the increase in cancer is restricted, largely if not wholly, to cancers with origins in ESKD or related to immune deficiency. For the former, the cancer risk is similar in dialysis and transplantation, but for immune deficiency-related cancers, the relative risk is much greater after transplantation.

Beyond anemia: the clinical impact of the physiologic effects of erythropoietin

Although we have known that oxygen tension affects erythrocyte production since the 19th century, we have only recently begun to understand many subtleties of erythropoietin (EPO) physiology. EPO administration has allowed hundreds of thousands of patients to avoid transfusions. With the beneficial effects so apparent a detailed understanding of the full clinical physiology of this plasma factor seemed less important. However, the unanticipated increase in mortality found in recent randomized studies is prompting a reassessment of this view. We will review what is known about the physiology of this plasma factor that, it is now clear, is more than just an erythrocyte production factor.

Comparison of stage at diagnosis of cancer in patients who are on dialysis versus the general population

BACKGROUND AND OBJECTIVES

Frequent medical encounters in patients with ESRD on dialysis may allow early detection of malignancies despite low rates of cancer screening in this population. It is therefore unclear whether dialysis patients are disadvantaged in terms of cancer diagnosis. This study compared stage at diagnosis of cancer in a population-based sample of patients with ESRD versus the general population.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

The Surveillance, Epidemiology, and End Results Medicare database was used to identify patients with ESRD and incident cancers from 1992 through 1999. Modified Poisson regression models were used to predict nonlocalized stage of cancer at diagnosis in patients with ESRD versus the general population, adjusting for demographics, cancer site, region, year of diagnosis, and comorbidity. Two general population comparisons were used: Standardized Surveillance, Epidemiology, and End Results public-use data and Medicare control subjects without ESRD matched 3:1 to patients with ESRD.

RESULTS

A total of 1629 patients with ESRD and incident cancer were identified. Overall, the likelihood of nonlocalized stage at diagnosis was not significantly different for patients with ESRD versus the standardized Surveillance, Epidemiology, and End Results general population or matched Medicare control subjects. Stratifying by cancer site, colorectal cancers were significantly more likely to be diagnosed earlier in the ESRD group, whereas prostate cancers were significantly more likely to be diagnosed at a later stage.

CONCLUSIONS

With the exception of prostate cancer, patients with ESRD are not more likely to present with later stage malignancies compared with the general population.

Screening, diagnosis, and treatment of cancer in long-term dialysis patients

Some have suggested that the American Cancer Society guidelines for cancer screening be applied to patients who are on long-term dialysis and have used cancer screening as a means of assessing delivered preventive health care to patients with ESRD. However, cancer screening is effective only when it leads to survival benefit (usually expressed as days of life saved) without incurring high financial costs. Certain cancers such as human papillomavirus-associated cervical and tongue cancer and urologic malignancies are more common among dialysis patients, yet because the expected remaining lifetime of most dialysis patients is shorter than the time lived to develop malignancy, cancer screening in dialysis patients as applied to the general population is ineffective from the perspective of both cost and survival benefit. Cancer screening in dialysis patients is therefore best provided in an individual patient-focused manner. The occurrence, diagnosis, and treatment of cancer as well as issues related to cancer screening in dialysis patients are discussed.

Genotoxicity of advanced glycation end products in mammalian cells

In patients with chronic renal failure, cancer incidence is enhanced. Since levels of advanced glycation end products (AGEs) are markedly elevated in renal insufficiency, we investigated potential effects of various AGEs on structural DNA integrity in tubule cells. The comet-assay was employed, a method based on the computer-aided microscopic analysis of single cells after electrophoretic separation of their nuclear DNA. Incubation of pig kidney LLC-PK1-cells for 24 h with AGE-BSA (AGE-bovine serum albumin), carboxymethyllysine-BSA as well as methylglyoxal-BSA resulted in a significant increase in DNA damage. Pretreatment of the cells with the proteases trypsin and bromelain abolished the AGE-induced comet-formation. This is in agreement with the idea that the observed genotoxicity of AGEs could be receptor-mediated and that proteases inactivate the extracellular domain of the receptor for AGEs. Binding of AGEs to the RAGE receptor leads to an increased intracellular formation of active oxygen species, which are known to induce DNA damage. It is concluded that AGEs induce genotoxicity in tubule cells, which may be involved in the enhanced cancer development in advanced kidney diseases.

Cancers of the kidney and urinary tract in patients on dialysis for end-stage renal disease: analysis of data from the United States, Europe, and Australia and New Zealand

Patients on maintenance dialysis have increased risk for cancer, especially in the kidney and urinary tract. In a retrospective cohort of 831,804 patients starting dialysis during 1980 to 1994 in the United States, Europe, or Australia and New Zealand, standardized incidence ratios (SIR) with 95% confidence intervals (CI) were calculated for kidney and bladder cancers. Risks for cancers of the kidney (SIR 3.6; CI 3.5 to 3.8) and bladder (SIR 1.5; CI 1.4 to 1.6) were increased, relatively more in younger than older patients and more in female patients (kidney: SIR 4.6, CI 4.3 to 4.9; bladder: SIR 2.7, CI 2.4 to 2.9) than male patients (kidney: SIR 3.2, CI 3.0 to 3.4; bladder: SIR 1.3, CI 1.2 to 1.3). SIR for kidney cancer were raised in all categories of primary renal disease, and for bladder cancer in all but diabetes and familial, hereditary diseases. Notably high SIR occurred in toxic nephropathies (chiefly analgesic nephropathy) and miscellaneous conditions (a category that includes Balkan nephropathy), the excess of kidney cancer in these conditions being urothelial in origin. SIR for kidney cancer rose significantly, and those for bladder cancer fell (not reaching significance) with time on dialysis. There was no association with type of dialysis. The pattern of increased risk for renal parenchymal cancer in dialysis patients is consistent with causation through acquired renal cystic disease and of urothelial cancers of the kidney and bladder with the carcinogenic effects of certain primary renal diseases.

The impact of iron and selenium deficiencies on iodine and thyroid metabolism: biochemistry and relevance to public health

Several minerals and trace elements are essential for normal thyroid hormone metabolism, e.g., iodine, iron, selenium, and zinc. Coexisting deficiencies of these elements can impair thyroid function. Iron deficiency impairs thyroid hormone synthesis by reducing activity of heme-dependent thyroid peroxidase. Iron-deficiency anemia blunts and iron supplementation improves the efficacy of iodine supplementation. Combined selenium and iodine deficiency leads to myxedematous cretinism. The normal thyroid gland retains high selenium concentrations even under conditions of inadequate selenium supply and expresses many of the known selenocysteine-containing proteins. Among these selenoproteins are the glutathione peroxidase, deiodinase, and thioredoxine reductase families of enzymes. Adequate selenium nutrition supports efficient thyroid hormone synthesis and metabolism and protects the thyroid gland from damage by excessive iodide exposure. In regions of combined severe iodine and selenium deficiency, normalization of iodine supply is mandatory before initiation of selenium supplementation in order to prevent hypothyroidism. Selenium deficiency and disturbed thyroid hormone economy may develop under conditions of special dietary regimens such as long-term total parenteral nutrition, phenylketonuria diet, cystic fibrosis, or may be the result of imbalanced nutrition in children, elderly people, or sick patients.

Preventive medical screening is not appropriate for many chronic dialysis patients

Establishing guidelines for the appropriate preventive medical care for chronic dialysis patients requires consideration of many factors. These include the population's underlying risk factors and expected survival, the effectiveness of screening procedures in improving the duration and/or quality of life, and the potential for renal transplantation. Although many nephrologists order and direct routine cancer screening in their dialysis patients, recent studies suggest such screening is not cost effective. Cardiovascular disease is the leading cause of death among end-stage renal disease (ESRD) patients and peripheral vascular disease is a leading cause of morbidity among dialysis patients, but even less is known about the cost-effectiveness of screening for peripheral vascular and cardiovascular disease risks in ESRD patients. Despite a recently reported overall standardized cancer incidence of 1.18 in dialysis patients compared with normal populations, the shortened expected survival of dialysis patients argues against routine cancer screening in this population. Dialysis units and nephrologists should focus cancer screening on individual patients and include specific cancer risk as well as expected survival assessments and transplant candidacy in their decisions to screen a patient for cancer. Routine cancer screening of all dialysis patients is not indicated. Additional study of the benefits and cost-effectiveness of screening ESRD patients for cardiovascular and peripheral vascular disease risk factors is needed.