Undescended testis and the risk of testicular cancer: importance of source and classification of exposure information

Dairy Consumption and Risk of Testicular Cancer: A Systematic Review

Dairy consumption has been studied extensively in terms of its relationship with testicular cancer (TC), yet this relationship remains unclear. In this systematic review, we aimed to answer whether TC development is associated with (a) high amounts of dairy product consumption, (b) the type of dairy product consumed, (c) increasing levels of dairy product consumption, and (d) dairy consumption during certain periods during the lifecourse. Following a systematic review of the literature, eight studies (all case-control studies) were included in our review. The included studies varied in terms of the dairy product(s) investigated (milk, cheese, cream, butter, and yoghurt) as well as the type of exposure to dairy consumption (e.g., high vs. low exposure, dose-response, and timing during lifecourse). We found that there was no strong evidence that high levels of dairy consumption are associated with risk of TC, conflicting evidence of a dose-response relationship, inconsistent evidence on whether certain types of dairy are more strongly associated with TC than others, and conflicting evidence that exposure during certain life-course periods affects TC risk more than other periods. There is no consistent evidence to support the premise that dairy product consumption is associated with the risk of TC development.

One to Watch: A Germ Cell Tumor Arising in an Undescended Testicle in Rubinstein-Taybi Syndrome

A male preterm infant was born with dysmorphic features consistent with Rubinstein-Taybi syndrome (RTS). An undescended right testicle was noted on examination. At 5 months of age he developed a palpable right-sided abdominal mass and an elevated alpha-fetoprotein. Histology revealed a malignant germ cell neoplasm arising within the undescended testis. This is the first reported case of a germ cell tumor occurring in a pediatric patient with RTS. Urologic abnormalities occur in approximately 52% of RTS patients, of which cryptorchidism is the commonest. Given the frequency of undescended testes in this population, closer screening may be warranted.

Management of non-obstructive azoospermia

Non-obstructive azoospermia (NOA) is defined as no sperm in the ejaculate due to failure of spermatogenesis and is the most severe form of male infertility. The etiology of NOA is either intrinsic testicular impairment or inadequate gonadotropin production. Chromosomal or genetic abnormalities should be evaluated because there is a relatively high incidence compared with the normal population. Although rare, NOA due to inadequate gonadotropin production is a condition in which fertility can be improved by medical treatment. In contrast, there is no treatment that can restore spermatogenesis in the majority of NOA patients. Consequently, testicular extraction of sperm under an operating microscope (micro-TESE) has been the first-line treatment for these patients. Other treatment options include varicocelectomy for NOA patients with a palpable varicocele and orchidopexy if undescended testes are diagnosed after adulthood, although management of these patients remains controversial. Advances in retrieving spermatozoa more efficiently by micro-TESE have been made during the past decade. In addition, recent advances in biotechnology have raised the possibility of using germ cells produced from stem cells in the future. This review presents current knowledge about the etiology, diagnosis, and treatment of NOA.

A population-based case-control study on social factors and risk of testicular germ cell tumours

OBJECTIVES

Incidence rates for testicular cancer have risen over the last few decades. Findings of an association between the risk of testicular cancer and social factors are controversial. The association of testicular cancer and different indicators of social factors were examined in this study.

DESIGN

Case-control study.

SETTING

Population-based multicentre study in four German regions (city states Bremen and Hamburg, the Saarland region and the city of Essen).

PARTICIPANTS

The study included 797 control participants and 266 participants newly diagnosed with testicular cancer of which 167 cases were classified as seminoma and 99 as non-seminoma. The age of study participants ranged from 15 to 69 years.

METHODS

Social position was classified by educational attainment level, posteducational training, occupational sectors according to Erikson-Goldthorpe-Portocarrero (EGP) and the socioeconomic status (SES) on the basis of the International SocioEconomic Index of occupational status (ISEI). ORs and corresponding 95% CIs (95% CIs) were calculated for the whole study sample and for seminoma and non-seminoma separately.

RESULTS

Testicular cancer risk was modestly increased among participants with an apprenticeship (OR=1.7 (95% CI 1.0 to 2.8)) or a university degree (OR=1.6 (95% CI 0.9 to 2.8)) relative to those whose education was limited to school. Analysis of occupational sectors revealed an excess risk for farmers and farm-related occupations. No clear trend was observed for the analyses according to the ISEI-scale.

CONCLUSIONS

Social factors based on occupational measures were not a risk factor for testicular cancer in this study. The elevated risk in farmers and farm-related occupations warrants further research including analysis of occupational exposures.

Cryptorchidism and testicular germ cell tumors: comprehensive meta-analysis reveals that association between these conditions diminished over time and is modified by clinical characteristics

INTRODUCTION

Risk of testicular germ cell tumors (TGCT) is consistently associated with a history of cryptorchidism (CO) in epidemiologic studies. Factors modifying the association may provide insights regarding etiology of TGCT and suggest a basis for individualized care of CO. To identify modifiers of the CO-TGCT association, we conducted a comprehensive, quantitative evaluation of epidemiologic data.

MATERIALS AND METHODS

Human studies cited in PubMed or ISI Web of Science indices through December 2011 and selected unpublished epidemiologic data were reviewed to identify 35 articles and one unpublished dataset with high-quality data on the CO-TGCT association. Association data were extracted as point and 95% confidence interval estimates of odds ratio (OR) or standardized incidence ratio (SIR), or as tabulated data. Values were recorded for each study population, and for subgroups defined by features of study design, CO and TGCT. Extracted data were used to estimate summary risk ratios (sRR) and evaluate heterogeneity of the CO-TGCT association between subgroups.

RESULTS

The overall meta-analysis showed that history of CO is associated with four-fold increased TGCT risk [RR = 4.1(95% CI = 3.6-4.7)]. Subgroup analyses identified five determinants of stronger association: bilateral CO, unilateral CO ipsilateral to TGCT, delayed CO treatment, TGCT diagnosed before 1970, and seminoma histology.

CONCLUSIONS

Modifying factors may provide insight into TGCT etiology and suggest improved approaches to managing CO. Based on available data, CO patients and their parents or caregivers should be made aware of elevated TGCT risk following orchidopexy, regardless of age at repair, unilateral vs. bilateral non-descent, or position of undescended testes.

A systematic review and meta-analysis of perinatal variables in relation to the risk of testicular cancer--experiences of the son

BACKGROUND

We undertook a systematic review and meta-analysis of perinatal variables in relation to testicular cancer risk, with a specific focus upon characteristics of the son.

METHODS

Literature databases Scopus, EMBASE, PubMed and Web of Science were searched using highly sensitive search strategies. Of 5865 references retrieved, 67 articles met the inclusion criteria, each of which was included in at least one perinatal analysis.

RESULTS

Random effects meta-analysis produced the following results for association with testicular cancer risk: birth weight [per kilogram, odds ratio (OR) = 0.94, 95% confidence interval (CI) 0.88-1.01, I(2)= 12%], low birth weight (OR = 1.34, 95% CI 1.08-1.67, I(2)= 51%), high birth weight (OR = 1.05, 95% CI 0.96-1.14, I(2)= 0%), gestational age (per week, OR = 0.95, 95% CI 0.92-0.98, I(2)= 38%; low vs not, OR = 1.31, 95% CI 1.07-1.59, I(2)= 49%), cryptorchidism (OR = 4.30, 95% CI 3.62-5.11, I(2)= 44%), inguinal hernia (OR = 1.63, 95% CI 1.37-1.94, I(2)= 38%) and twinning (OR = 1.22, 95% CI 1.03-1.44, I(2)= 22%). Meta-analyses of the variables birth length, breastfeeding and neonatal jaundice did not provide evidence for an association with testicular cancer risk. When low birth weight was stratified by data ascertainment (record/registry vs self-report), only the category of self-report was indicative of an association. Meta-regression of data ascertainment (record/registry vs self-report) inferred that record-/registry-based studies were less supportive of an association with gestational age (per week = 0.97, 95% CI 0.94-1.00, I(2)( )= 29%; low vs not = 1.08, 95% CI 0.91-1.28, I(2)= 32%).

CONCLUSION

In conclusion, this systematic review and meta-analysis finds evidence that cryptorchidism, inguinal hernia and twinning, and tentative evidence that birth weight and gestational age, are associated with risk of testicular cancer.

Risk of contralateral testicular cancer among men with unilaterally undescended testis: a meta analysis

The association between undescended testis (cryptorchidism) and testicular cancer is established, but it is not known whether the risk of testicular cancer among men with unilateral maldescent is increased in both testes, or only on the undescended side. This is a meta-analysis of 11 case-control studies and 1 cohort study that all assessed the risk of testicular cancer separately for the undescended and descended testis. We used fixed-effects meta-analysis to calculate pooled estimates and 95% confidence intervals (CIs) for the relative risk. Of 199 tumors in men with unilateral cryptorchidism, 158 (79%) were on the ipsilateral side and 41 (21%) on the contralateral side. The pooled relative risks for testicular cancer in the ipsilateral and contralateral testis were 6.33 (95% CI, 4.30 to 9.31) and 1.74 (95% CI, 1.01 to 2.98), respectively. We conclude that in 1-sided undescended testis, the risk of testicular cancer may be increased in both testes, although to a much greater extent on the ipsilateral side.

[Is there any relationship between rural environmental factors and reproductive health in the Pampa Humeda in Argentina?]

The relationship between environmental factors and health is well known. Rural environmental influences on reproductive health have been properly proved, both in animals and humans. In Latin America, few studies have been conducted in this area. The current project is based on the description of relationships between reproductive health and environmental factors in rural populations, characterized by specific environmental characteristics. Three variables were evaluated: male-to-female birth ratio, male urogenital malformations (cryptorchidism and hypospadias), and endocrine-related cancer incidence. Five rural communities in the Pampa Humeda in Argentina were selected, and the data were compared to the national mean. Biomedical data and environmental risk factors were correlated through a geographic information system. The ratio of male to female births did not show any differences. Malformations showed very significant differences. Endocrine-related cancers showed higher incidence rates compared to the national mean, particularly in some communities. In conclusion, there is a relationship between environmental factors and reproductive health conditions in this region.

Subtype-specific incidence of testicular cancer in Germany: a pooled analysis of nine population-based cancer registries

Comparisons of incidence estimates of testicular cancer subtypes beyond seminoma and non-seminoma are virtually missing in the epidemiologic literature. We analysed incidence data from population-based German cancer registries to provide subtype-specific incidences of testicular cancer. We pooled data from nine cancer registries from 1998 to 2003. We estimated incidence and mortality time trends of West and East Germany. Incidence and mortality were standardized by the European standard population. The annual percentage incidence change from 1961 through 1989 was 4.9% in East Germany and 3.0% from 1970 through 2004 in Saarland. Incidence increases were the most pronounced among adolescents and young men aged 15-49 years. In 1998-2003, the seminoma incidence rate was 5.1 per 100,000; among non-seminomas, the rates were the highest for malignant teratoma (1.6 per 100,000), followed by embryonal carcinoma (1.2 per 100,000). Testicular lymphomas were rare (0.1 per 100,000). The incidence of testicular cancer among children aged 0-14 years was nearly constant from 1987 through 2004. Majority of these cancers were yolk sac tumours (0.1 per 100,000). In East and West Germany, rates of embryonal carcinoma in the early periods were considerably lower than the rates of malignant teratoma. In the most recent periods, rates of embryonal carcinoma became quite similar to the rates of malignant teratoma. The mortality decline started in West Germany roughly 12 years earlier than in East Germany. The later start of the mortality decline in East Germany may be because of a later introduction of platinum-based chemotherapy compared to West Germany.

Risk of testicular germ-cell tumours in relation to childhood physical activity

The US Servicemen's Testicular Tumor Environmental and Endocrine Determinants (STEED) case–control study of testicular germ-cell tumours (TGCTs) enrolled participants and their mothers in 2002–2005. Hours of sports or vigorous childhood physical activity per week were ascertained for three time periods; 1st–5th grades, 6th–8th grades and 9th–12th grades. Son- and mother-reports were analysed separately and included 539 control son–mother pairs and 499 case son–mother pairs. Odds ratios and 95% confidence intervals were produced. The analysis of the sons' responses found no relationship between childhood physical activity and TGCT, while the mothers' analysis found an inverse association, which was solely due to nonseminoma. Future studies should seek to validate responses further using recorded information sources such as school records.

Adolescent Milk Fat and Galactose Consumption and Testicular Germ Cell Cancer

Recent case-control studies suggested that dairy product consumption is an important risk factor for testicular cancer. We examined the association between consumption of dairy products, especially milk, milk fat, and galactose, and testicular cancer in a population-based case-control study including 269 case and 797 controls (response proportions of 76% and 46%, respectively). Dietary history was assessed by food frequency questions for the index persons and through their mothers including diet 1 year before interview and diet at age 17 years. We used conditional logistic regression to calculate odds ratios as estimates of the relative risk (RR), 95% confidence intervals (95% CI), and to control for social status and height. The RR of testicular cancer was 1.37 (95% CI, 1.12-1.68) per additional 20 servings of milk per month (each 200 mL) in adolescence. This elevated overall risk was mainly due to an increased risk for seminoma (RR, 1.66; 95% CI, 1.30-2.12) per additional 20 milk servings per month. The RR for seminoma was 1.30 (95% CI, 1.15-1.48) for each additional 200 g milk fat per month and was 2.01 (95% CI, 1.41-2.86) for each additional 200 g galactose per month during adolescence. Our results suggest that milk fat and/or galactose may explain the association between milk and dairy product consumption and seminomatous testicular cancer.

Intersex genetic anomalies with malignant potential

PURPOSE OF REVIEW

Mutations in genes contributing to sexual determination and differentiation can cause clinical syndromes with potential for the development of malignant tumors. This article focuses on intersex disorders requiring surveillance for and/or operation to prevent or treat malignancies.

RECENT FINDINGS

Classification of intersex disorders into risk groups gives guidance to physicians about children who are vulnerable to malignant degeneration of the gonads or kidneys. The gonads most at risk are both dysgenetic and intra-abdominal, and early gonadectomies are recommended as malignancies have been reported in infancy. Predominant risk groups include syndromes of gonadal dysgenesis and Ullrich-Turner syndrome. Partial gonadectomy is feasible in true hermaphrodites commensurate with sex of rearing. Histologically normal intra-abdominal gonads may be left through puberty (androgen insensitivity syndromes). A palpably normal descended gonad in a child with a Y chromosome can be observed if the child is reared as male. Certain intersex syndromes with splice variants of the WT1 gene are susceptible to Wilms' tumors (Frasier and Denys-Drash syndromes).

SUMMARY

Prevention or early recognition of malignancy in intersex disorders requires knowledge of the risk factors including dysgenetic gonads, a Y chromosome with intra-abdominal gonads and dysgenetic syndromes with WT1 gene splice variants. This paper describes the evolution toward laparoscopic gonadectomy in intersex patients, as a means to remove abnormal gonads and associated ductal structures as dictated by the disease or syndrome.

Carpenters, cabinetmakers, and risk of testicular germ cell cancer

OBJECTIVE

A recent cohort study showed an increased risk of testicular cancer among members of the United Brotherhood of Carpenters and Joiners of America. We explored our data of a German population-based case-control study on the etiology of testicular cancer with regard to this association.

METHODS

The case-control study included 269 testicular cancer cases and 797 controls. We applied conditional logistic regression to calculate odds ratios (OR) and 95% confidence intervals (95% CIs).

RESULTS

People who worked as cabinetmakers or carpenters had an OR of 0.84 (95% CI = 0.45-1.56). Risks were increased among cabinetmakers who worked at least 15 years ago (OR = 5.81, 95% CI = 1.20-28.09). Ever being employed as a carpenter was associated with a reduced OR of 0.59 (95% CI = 0.24-1.46).

CONCLUSIONS

Cabinetmakers may be at an increased risk of testicular cancer.

Residential exposure to overhead high-voltage lines and the risk of testicular cancer: results of a population-based case-control study in Hamburg (Germany)

BACKGROUND

In a population-based case-control study we examined the association between residential exposure to overhead high-voltage lines and testicular cancer.

METHODS

We recorded the residential biography of cases with testicular cancer identified by the Hamburg Cancer Registry and of controls that were randomly selected from the mandatory registry of residents in Hamburg. The study included 145 incident cases between 15 and 69 years of age, diagnosed between 1995 and 1997, and 313 controls, matched for age in 5-year strata. In model A, exposure was defined by distance (ever vs never). Model B took into account residence time and the inverse distance from the nearest high-voltage line. It distinguished between low and high exposure, the never exposed persons serving as a reference group. Odds ratios (ORs) and corresponding 95% confidence intervals (CIs) were calculated by unconditional logistic regression. For men below the age of 40 years and men aged 40 years and over separate analyses were carried out.

RESULTS

Within a corridor of 100 m the prevalence of exposure to high-voltage lines in Hamburg was 6.9% in cases and 5.8% in controls (OR=1.3; 95% CI=0.56-2.80). In the more complex model B we found an OR of 1.2 (95% CI=0.60-2.47) for low exposure and 1.7 (95% CI=0.91-3.32) for high exposure. Younger men show slightly increased risks in both models.

CONCLUSIONS

In all, residential exposure to high-voltage lines did not seem to be a major risk factor for testicular cancer in our study. Yet, the fact that risks for men below the age of 40 years were slightly increased in both exposure models deserves further attention.

Testicular, Other Genital, and Breast Cancers in First-Degree Relatives of Testicular Cancer Patients and Controls

Previous studies showed an increased prevalence of testicular cancer among fathers and brothers of testicular cancer patients. We examined whether testicular, other genital, and breast cancers aggregate in parents and siblings of testicular cancer patients in a population-based case-control study, including males, ages 15 to 69 years at diagnosis, with primary malignant tumors of the testes or extragonadal germ cell tumors. Controls were ascertained through the mandatory registries of residents and frequency matched to the cases by age and region of residence. In a face-to-face interview, 269 cases and 797 controls provided health-related information on parents and siblings. We calculated odds ratios (OR) and corresponding 95% confidence intervals (95% CI) based on the generalized estimating equations technique, adjusting for the matching variables and relatives' age. Three (1.1%) fathers and eight (3.2%) brothers of cases were affected with testicular cancer compared with four (0.5%) fathers and two (0.2%) brothers of controls. The OR (95% CI) of familial testicular cancer was 6.6 (2.35-18.77). Only nonseminoma patients had fathers with testicular cancer, whereas the affected brothers were all related to seminoma patients. Overall, we found an increased risk for genital other than testicular cancers (OR 2.5, 95% CI 1.43-4.43). For breast cancer, we detected an increased risk in sisters (OR 9.5, 95% CI 2.01-45.16, adjusted for age of study participant and age of sister) but not in mothers. Our findings support the hypothesis that testicular and other genital cancers have a common familial component that may be due to genetic and shared exogenous factors such as estrogen exposure during fetal development.

Clinical epidemiology of testicular germ cell tumors

Clinical epidemiology is sometimes called the basic science of clinical medicine. In terms of the pathogenesis of testicular germ cell tumors (GCTs), clinical epidemiology analyzes suspected risk factors. The present review highlights the risk factors established so far and briefly summarizes those factors currently under investigation. In analogy to the methods of evidence based medicine, this review attributes levels of evidence to each of the putative risk factors. Level I represents highest quality of evidence while level V denotes the lowest level. So far, undescended testis (UDT), contralateral testicular GCT and familial testis cancer are established risk factors attaining high levels of evidence (levels I-III a). In a meta-analysis of 21 studies exploring the association of UDT with GCT risk, an over-all relative risk (RR) of 4.8 (95% confidence interval 4.0-5.7) was found. Contralateral testicular GCT involves a roughly 25-fold increased RR of GCT, while familial testis cancer constitutes a RR of 3-10. Infertility, testicular atrophy, and twin-ship represent risk factors with lesser levels of evidence (level III a). There is also some evidence for HIV infection being a predisposing factor for GCT (level IV a). Scrotal trauma is probably not associated with GCT risk. The estrogen excess theory implies high estrogen levels during the first trimester of pregnancy. As a consequence, primordial germ cells lose track of the normal developmental line and transform into premalignant cells that later become testicular intraepithelial neoplasia (TIN), the precursor of full-blown testicular GCT. Surrogate parameters for high gestational estrogen levels are investigated in case control studies. Such factors are maternal age >30 years, first-born, low birth weight, maternal breast cancer, high sex-ratio of siblings. So far, the sum of evidence is promising but still conflicting (especially for level III b). Another novel theory is the childhood nutrition hypothesis. This concept postulates a modulating or "catalyzing" effect by high dietary intake during childhood on the pathogenesis of testicular GCT. A surrogate parameter of early childhood nutrition is adult height. So far, 12 controlled studies have looked to the possible association of attained height and GCT risk of which six demonstrated a significant association. Thus, the sum of evidence corresponds to level III b. This concept is appealing because it would explain several hitherto unexplained epidemiological features of GCT.

Firefighting and risk of testicular cancer: results from a German population-based case-control study

BACKGROUND

There is some evidence of an elevated risk for testicular cancer among firefighters.

METHODS

We performed a population-based case-control study including 269 testicular cancer cases and 797 controls matching on age and region with a special focus on occupational exposures. Job tasks were coded according to the International Standard Classification of Occupations (ISCO 68). We used conditional logistic regression to calculate odds ratios (OR).

RESULTS

Three controls (0.4%) and four cases (1.5%) ever worked as firefighters. Firefighters showed an increased odds of testicular cancer in the matched evaluation (OR = 4.3, 95% confidence interval (95% CI) 0.7-30.5). The adjustment for a history of cryptorchidism or family history of testicular cancer did not alter our results.

CONCLUSION

Although the association between firefighting and testicular cancer risk is based on only small numbers of exposed subjects in our study, the finding is consistent with a recent cohort study from New Zealand. Occupational hazards experienced by firefighters may increase the risk of testicular cancer.

Hypomethylated X chromosome gain and rare isochromosome 12p in diverse intracranial germ cell tumors

Twenty-five primary intracranial germ cell tumors (11 germinomas, 5 teratomas, 5 mixed teratomas-germinomas. 1 mixed choriocarcinoma-teratoma, 1 yolk sac tumor, 1 mixed yolk sac tumor-teratoma, and 1embryonal carcinoma; from 24 males and 1 female) were studied by fluorescence in situ hybridization with probes to the X and Y chromosomes, chromosome 12p, the CDKN2A/p16 gene, and chromosome 13q-loci previously noted to be altered in either intracranial or systemic germ cell tumors. An increased number of X chromosomes, typically 1 extra copy, was observed in 23 of 25 cases (92%), with methylation-sensitive PCR demonstrating that the additional X chromosomes were hypomethylated in 13 of 16 (81%) studied tumors. Five cases (20%) had increased copy numbers of 12p (including tumors with isochromosome 12p), and 3 (12%) had 13q loss. No tumors had CDKN2A/p16 deletion or mutation, and 16 of 25 (64%) were positive for p16 expression by immunohistochemistry. Genetic alterations such as isochromosome 12p, 13q loss and CDKN2A/p16 are therefore not common in intracranial germ cell tumors. However, gains of hypomethylated, active X chromosomes occur in nearly all intracranial germ cell tumors, regardless of histological subtype. Along with the observed male predominance of intracranial germ cell tumors and the predisposition in Klinefelter syndrome patients for these lesions, the data argue strongly that sex chromosome aberrations, rather than isochromosome 12p, are integral to intracranial germ cell tumorigenesis