Risk factors for testicular germ cell tumours by histological tumour type. United Kingdom Testicular Cancer Study Group

International Trends in the Incidence of Testicular Cancer: Lessons from 35 Years and 41 Countries

BACKGROUND

Incidence rates of testicular cancer (TC) have been increasing in many countries since, at least, the mid-20th century without clear explanation. Examining the varying trends across countries and time provides clues to understanding the causes of TC.

OBJECTIVE

We have presented incidence data from 41 countries and evaluated incidence trends for the 35-yr period from 1978 to 2012.

DESIGN, SETTING, AND PARTICIPANTS

Cancer registry data from Cancer Incidence in Five Continents (CI5) volumes V-XI, CI5plus, and the NORDCAN database were analysed.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

Age-standardised rates of TC overall and by histological type were calculated. A joinpoint regression model of the natural log-transformed rates was used to calculate the average annual percent change (AAPC) in incidence. Age-period-cohort modelling was used to examine the effect of birth cohort on rates.

RESULTS AND LIMITATIONS

While the highest incidence of TC remains in Northern Europe, the gap is closing between higher- and lower-incidence regions. Age-period-cohort modelling found flattening of risk among recent cohorts in Denmark and the UK, a steady increase in risk in the USA (particularly for seminomas), and an increase in risk among more recent cohorts in Costa Rica, Croatia, and Slovakia.

CONCLUSIONS

The gap between low- and high-incidence countries is closing due to increases in the former and stabilisation in the latter. Understanding the causes of these and other differences in incidence rates between, and within, countries may help further our understanding of the aetiology of this cancer.

PATIENT SUMMARY

We examined the rates of testicular cancer in different countries over time. These rates have been increasing, although the rates in high-incidence countries seem to be slowing down, while rates in low-incidence countries are catching up. These trends might help us understand what is causing testicular cancer in general.

The puzzling incidence of testicular cancer in New Zealand: what can we learn?

BACKGROUND

Testicular germ cell tumour is the most common cancer to be diagnosed among young men. In New Zealand, we have observed some puzzling trends in the epidemiology of this disease.

METHODS

We have conducted a narrative review of available evidence regarding the puzzling epidemiology of testicular germ cell tumour in New Zealand and discussed the possible drivers of these trends.

RESULTS AND DISCUSSION

Whereas testicular cancer is most commonly a disease of White men, in New Zealand it is the indigenous Māori population that suffer by far the greatest rate of disease (age-adjusted relative risk: 1.80, 95% CI 1.58-2.05). Even more curiously, the rate of testicular germ cell tumour among Māori men aged 15-44 (28/100,000) is substantially greater than for Pacific Island men (9/100,000), a rare example of divergence between these two populations in terms of the incidence of any disease (cancer or otherwise). Our observations beg the following questions: first, why are rates of testicular germ cell tumour so much higher among Māori New Zealanders compared to the already high rates observed among European/Other New Zealanders? Second, why are rates of testicular germ cell tumour so completely divergent between Māori and Pacific New Zealanders, when these two groups typically move in parallel with respect to the incidence of given diseases? Finally, what might we learn about the factors that cause testicular germ cell tumour in general by answering these questions?

CONCLUSION

This review examines the possible drivers of our observed disparity, discusses their feasibility, and highlights new work that is underway to further understand these drivers.

Physical activity and risk of testicular cancer: a systematic review

BACKGROUND

Physical activity has been implicated as a risk factor in the development of testicular cancer (TC), but the relationship remains controversial. This systematic review pooled available evidence regarding this association.

METHODS

Using Boolean search terms and following PRISMA guidelines, we examined the risk of TC across three categories of exposure: intensity (i.e. comparison of risk between those previously exposed to high, moderate and low levels of physical activity); dose-response (i.e. whether risk of TC increases or decreases with increasing exposure to physical activity); and the role of timing of physical activity (i.e. during early childhood or adolescence).

RESULTS

Thirteen studies (11 case-control studies, 2 cohort studies) were included in the review. While some studies have reported a strong protective effect of high levels of physical activity on risk of TC, others have reported either no relationship or a weak direct association; and while a dose-response relationship has been identified across several studies, this relationship has been observed in both directions. Similarly conflicting results exist in terms of individual types of activity and the lifecourse timing of the physical activity. Reasons for this inconsistency may include the absence of any association, heterogeneous assessment of physical activity, misclassification bias and difference in sample sizes.

CONCLUSIONS

On balance, there is presently no strong evidence of an association between physical activity and risk of subsequent TC. This review highlights key areas for future investigation that may clarify any association between physical activity and risk of testicular cancer.

Adult Consequences of Self-Limited Delayed Puberty

Delayed puberty is a common condition defined as the lack of sexual maturation by an age ≥2 SD above the population mean. In the absence of an identified underlying cause, the condition is usually self-limited. Although self-limited delayed puberty is largely believed to be a benign developmental variant with no long-term consequences, several studies have suggested that delayed puberty may in fact have both harmful and protective effects on various adult health outcomes. In particular, height and bone mineral density have been shown to be compromised in some studies of adults with a history of delayed puberty. Delayed puberty may also negatively affect adult psychosocial functioning and educational achievement, and individuals with a history of delayed puberty carry a higher risk for metabolic and cardiovascular disorders. In contrast, a history of delayed puberty appears to be protective for breast and endometrial cancer in women and for testicular cancer in men. Most studies on adult outcomes of self-limited delayed puberty have been in small series with significant variability in outcome measures and study criteria. In this article, we review potential medical and psychosocial issues for adults with a history of self-limited delayed puberty, discuss potential mechanisms underlying these issues, and identify gaps in knowledge and directions for future research.

Transitional Urology for Male Adolescents: What Adult Urologists Should Know

In recent years, there has been increasing interest in transitional urology, or how to best prepare patients with major congenital urologic diseases, such as bladder exstrophy and neuropathic bladder, to manage their own health care with adult urologists. However, common pediatric urologic conditions may be encountered by the adult urologist with more regularity. This review focuses on three relatively common conditions which may be identified in childhood, the consequences from which a patient may seek help from an adult urologist: cryptorchidism, varicocele, and Klinefelter syndrome.

Clinical and histopathological results of the adult patients with unilateral cryptorchidism

OBJECTIVE

To evaluate the clinical and histopathological results of adult unilateral cryptorchidism patients.

MATERIAL AND METHODS

Data from adult unilateral cryptorchidism patients that underwent orchiectomy in our clinic between between January 2004 and March 2013 were retrospectively evaluated. Patients were divided into three groups as intra-abdominal, inguinal canal and superficial inguinal region according to the location of the undescended testes. Patients were also grouped according to their testicular volume (<4 cc, 4.1-12 cc, and >12 cc). Histopathology results of orchiectomy specimens were classified as follows: 1. Sertoli cells only, testicular atrophy and vanished testis (anorchia) 2. Hypospermatogenesis, and 3. Maturation arrest. Patients were grouped as normospermia, azoospermia and oligo/astheno/teratospermia groups according to semen analysis results. Correlations between testicular localization, testicular size, semen analysis and pathology results were evaluated. Incidental tumor detection rates were also calculated.

RESULTS

Two hundred and forty-four adult unilateral cryptorchidism patients underwent orchiectomy in our clinic. There was no a significant relationship between location of the testis and testicular pathology results (p=0.707). Most common semen analysis results was normospermia in patients with high testicular volume group however azoospermia and oligoasthenospermia observed commonly in patients with low testicular volume group. There was a significant relationship between testicular volume and semen analysis results (p=0.023). No significant relationship was observed between semen analysis and pathological results (p=0.929). After an evaluation of all factors with possible effects on the semen analysis results, only testicular volume (p=0.036) was found to have a significant impact. Only one case (0.4%) was incidentally diagnosed seminoma after a review of 233 patients with available histopathological results on record.

CONCLUSION

Adult unilateral cryptorchidism has a minimal effect on male fertility or even this effect can be overlooked. Low detection rates of incidental germ cell tumors also make an orchiectomy decision questionable in such cases.

Association between Testicular Cancer and Epididymoorchitis: A Population-Based Case-Control Study

Even though epididymoorchitis and testicular cancer (TC) may have similar pathophysiological pathways, no prior study has attempted to determine the association between these two diseases. This case-control study investigated the relationship between TC and prior epididymoorchitis by using a large population-based database. We used the Taiwan Longitudinal Health Insurance Database 2005 to select 372 patients who had received a diagnosis of TC and 3,720 age-matched controls without TC. We found that of the total sample of 4,092 patients, 53 (1.3%) had received a diagnosis of epididymoorchitis prior to the index date. Patients with TC had a higher prevalence of prior epididymoorchitis than that of patients without TC (11.0% vs. 0.3%, p < 0.001). Conditional logistic regression showed that prior epididymoorchitis was significantly associated with TC (crude OR = 38.24, 95% CI = 19.91-73.46). The association remained statistically significant even after adjustment for the other variables (OR = 47.17, 95% CI = 23.83-93.40). This study showed that patients with TC have higher odds of prior epididymoorchitis than do those without TC even after adjustment for potential confounders.

Etiology and early pathogenesis of malignant testicular germ cell tumors: towards possibilities for preinvasive diagnosis

Malignant testicular germ cell tumors (TGCT) are the most frequent cancers in Caucasian males (20-40 years) with an 70% increasing incidence the last 20 years, probably due to combined action of (epi)genetic and (micro)environmental factors. It is expected that TGCT have carcinoma in situ(CIS) as their common precursor, originating from an embryonic germ cell blocked in its maturation process. The overall cure rate of TGCT is more than 90%, however, men surviving TGCT can present long-term side effects of systemic cancer treatment. In contrast, men diagnosed and treated for CIS only continue to live without these long-term side effects. Therefore, early detection of CIS has great health benefits, which will require an informative screening method. This review described the etiology and early pathogenesis of TGCT, as well as the possibilities of early detection and future potential of screening men at risk for TGCT. For screening, a well-defined risk profile based on both genetic and environmental risk factors is needed. Since 2009, several genome wide association studies (GWAS) have been published, reporting on single-nucleotide polymorphisms (SNPs) with significant associations in or near the genes KITLG, SPRY4, BAK1, DMRT1, TERT, ATF7IP, HPGDS, MAD1L1, RFWD3, TEX14, and PPM1E, likely to be related to TGCT development. Prenatal, perinatal, and postnatal environmental factors also influence the onset of CIS. A noninvasive early detection method for CIS would be highly beneficial in a clinical setting, for which specific miRNA detection in semen seems to be very promising. Further research is needed to develop a well-defined TGCT risk profile, based on gene-environment interactions, combined with noninvasive detection method for CIS.

Individualized Treatment Guidelines for Postpubertal Cryptorchidism

Cryptorchidism is a well-known congenital anomaly in children. However, its diagnosis is often delayed for reasons including patient unawareness or denial of abnormal findings in the testis. Moreover, it has been difficult to establish an optimal treatment strategy for postpubertal cryptorchidism, given the small number of patients. Unlike cryptorchidism in children, postpubertal cryptorchidism is associated with an increased probability of neoplasms, which has led orchiectomy to be the recommended treatment. However, routine orchiectomy should be avoided in some cases due to quality-of-life issues and the potential risk of perioperative mortality. Based on a literature review, this study proposes individualized treatment guidelines for postpubertal cryptorchidism.

Obscure etiology, unusual disparity: the epidemiology of testicular cancer in New Zealand

PURPOSE

Testicular cancer (TC) remains perplexing, both in terms of what causes the disease and why certain populations are at greater risk of developing it. In New Zealand, an unusual ethnic disparity exists, whereby the indigenous Māori population suffer the highest rates of disease. In this study, we further describe the epidemiology of TC in the New Zealand context.

METHODS

Eligible patients diagnosed with TC between 2000 and 2011 (n = 1,800) were determined from the NZ Cancer Registry and linked to mortality data. Census data were used to estimate population incidence of TC and tumor sub-type by ethnic group. Kaplan-Meier and Cox regression analyses were used to compare survival between ethnic groups.

RESULTS

Māori males aged 15-44 were 80% more likely to be diagnosed with TC compared to European/Other males [age-standardized relative risk (RR) 1.80, 95% CI 1.58-2.05]. By contrast, disease burden was comparatively low among Pacific and Asian populations. Māori had a greater incidence of both seminoma (RR 1.88, 95% CI 1.52-2.22) and non-seminoma (RR 1.67, 95% CI 1.35-2.07) germ cell tumors than the European/Other population, reducing the likelihood that our observed disparity is driven by differential propensity to one given sub-type among Māori. Māori had poorer survival outcomes [cancer-specific adjusted hazard ratio (HR) 2.29, 95% CI 1.14-4.59] than the European/Other population.

CONCLUSIONS

Understanding the drivers of New Zealand's unusual incidence disparities--particularly between Māori and Pacific--could further our understanding of the key exposures involved in TC etiology.

Role of primary chemotherapy in management of large tumors of undescended testis: Our experience

OBJECTIVE

This study aimed to share our experience with tumors of undescended testis (UDT) and to assess the impact of primary cisplatin-based chemotherapy on such tumors.

MATERIALS AND METHODS

This study included the cases of tumor in UDT from February 2005 to December 2011. Evaluation of the cases was done with proper clinical examination and laboratory investigations along with tumor markers (alfa-feto protein, beta-human chorionic gonadotropin, lactate dehydrogenase) and contrast-enhanced computed tomography abdomen. Fine needle aspiration cytologywas done in all cases. Primary chemotherapy with three cycles of bleomycin, etoposide, and cisplatin regimen at three weekly intervals started in all cases. Response to treatment was seen after four weeks of the third cycle.

RESULTS

Fourteen cases (12.5%) of germ cell tumor in UDT out of 112 cases of germ cell tumor of the testis were included. The age ranged from 16-60 years. Histological diagnosis was pure seminoma in all cases. After three cycles of BEP regime, complete response was seen in 11 cases and partial response in three cases where the residual tumor was excised along with retroperitoneal lymph node dissection RPLND. Of the 14 cases, 13 were in regular follow-up and one was lost to follow-up. All on follow-up were doing well without recurrence till now.

CONCLUSION

Surgical removal of the primary tumor in UDT with or without bulky metastasis is complicated. Primary chemotherapy with cisplatin-based regimen is a good option in such cases.

Age at puberty and risk of testicular cancer: a meta-analysis

Testicular cancer is one of the most rapidly increasing tumour types but its aetiology is still largely unexplained. Cryptorchidism and familial testicular cancer, established risk factors, explain less than 10% of all cases. Among investigated post-natal factors, early puberty was suggested as a potential risk factor but the topic has been poorly investigated. We undertook a meta-analysis of the effect of age at puberty on testicular cancer risk, attempting at enhancing the homogeneity in the definition of the exposure among studies to obtain valid pooled estimates. Search strategies were conducted in PubMed on December 2011. All markers of puberty onset (age at voice change, age when started shaving and reported age at onset) were considered. We re-categorized age at puberty from all studies into a common three-level variable: younger than peers, same age as peers, older than peers. A total of 391 references were retrieved, of which 12 met the inclusion criteria. Later puberty appeared to be protective. In particular late vs. same age at start shaving gave an OR of 0.84 (95% CI: 0.75-0.95, five studies); late vs. same age at voice change gave an OR of 0.87 (95% CI: 0.75-1.01, five studies); and later age than peers at reported onset of puberty gave an OR of 0.81 (95% CI: 0.73-0.89, eight studies). Early puberty showed no effect on testicular cancer risk. This meta-analysis has found consistent evidence of a decreased risk of testicular cancer in association with later puberty, suggesting that post-natal factors may contribute to testicular cancer risk.

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.

International trends in the incidence of testicular cancer, 1973-2002

BACKGROUND

Whereas testicular cancer incidence rates have been widely reported in populations of Northern European ancestry, rates in other populations have been less frequently examined. In a prior report, global testicular cancer incidence rates and trends for the years 1973 to 1997 were summarized. The current report extends these analyses with an additional 5 years of data from Cancer Incidence in Five Continents.

METHODS

Age-standardized incidence rates over successive 5-year time periods were obtained for populations in the Americas, Asia, Europe, and Oceania.

RESULTS

In general, testicular cancer incidence remained highest in Northern European populations (8.0-9.0 per 100,000) and lowest in Asian and African populations (<1 per 100,000). One notable exception to this pattern, however, was the very high rate reported by the Valdivia, Chile registry (8.8 per 100,000). In many populations, rates rose between 1973 and 2002, although the increases were strongest and most consistent among populations of European ancestry. In certain European populations, such as those of Denmark and of Geneva, Switzerland, some recent plateauing of rates was evident. There was little evidence of increase and possible evidence of a modest decline in rates among east Asian populations. Trends by histology (seminoma and nonseminoma) were generally similar to one another.

CONCLUSIONS

Risk of testicular cancer remains relatively high in Northern European populations and low in Asian and African populations. Similar trends by histology suggest common risk factors. EFFECT: Reasons for increasing rates among Northern Europeans and stable or declining rates among East Asians are unexplained, supporting the need for future etiologic studies.

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.

Ethnic and socioeconomic trends in testicular cancer incidence in New Zealand

Ethnic differences in testicular cancer incidence within countries are often sizeable, with white populations consistently having the highest ethnic-specific rates. Many studies have found that high socioeconomic status is a risk factor for testicular cancer. The objectives of this article are to test whether trends in testicular cancer incidence have varied by ethnicity and socioeconomic position in New Zealand between 1981 and 2004. Five cohorts of the entire New Zealand population for 1981-1986, 1986-1991, 1991-1996, 1996-2001 and 2001-2004 were created, and probabilistically linked to cancer registry records, allowing direct determination of ethnic and household income trends in testicular cancer incidence. There were more than 2,000 cases of testicular cancer over the study period. We found increasing rates of testicular cancer for all ethnic and income groups since 1990s. Maori had higher rates, and Pacific and Asian lower rates than European/other men with rate ratios pooled over time of 1.51 (95% CI 1.31-1.74), 0.40 (95% CI 0.26-0.61) and 0.54 (95% CI 0.31-0.94), respectively. Overall, men with low incomes had higher risk of testicular cancer than those with high incomes (pooled rate ratio for lowest to highest income groups = 1.23; 95% CI 1.05-1.44). There was no strong evidence that disparities in testicular cancer incidence have varied by ethnicity or household income over time. Given the lack of understanding of the etiology of testicular cancer, the unusual patterns identified in the New Zealand context may provide some etiological clues for future novel research.

Identification of a heritable model of testicular germ cell tumor in the zebrafish

Germ cell tumors (GCTs) affect infants, children, and adults and are the most common cancer type in young men. Progress in understanding the molecular basis of GCTs has been hampered by a lack of suitable animal models. Here we report the identification of a zebrafish model of highly penetrant, heritable testicular GCT isolated as part of a forward genetic screen for cancer susceptibility genes. The mutant line develops spontaneous testicular tumors at a median age of 7 months, and pedigree analysis indicates dominant inheritance of the GCT susceptibility trait. The zebrafish model exhibits disruption of testicular tissue architecture and the accumulation of primitive, spermatogonial-like cells with loss of spermatocytic differentiation. Radiation treatment leads to apoptosis of the tumor cells and tumor regression. The GCT-susceptible line can serve as a model for understanding the mechanisms regulating germ cells in normal development and disease and as a platform investigating new therapeutic approaches for GCTs.

Etiologic factors in testicular germ-cell tumors

Globally, testicular cancer incidence is highest among men of northern European ancestry and lowest among men of Asian and African descent. Incidence rates have been increasing around the world for at least 50 years, but mortality rates, at least in developed countries, have been declining. While reasons for the decreases in mortality are related to improvements in therapeutic regimens introduced in the late 1970s, reasons for the increase in incidence are less well understood. However, an accumulating body of evidence suggests that testicular cancer arises in fetal life. Perinatal factors, including exposure to endocrine-disrupting chemicals, have been suggested to be related to risk.

Paediatric germ cell tumours and congenital abnormalities: a Children's Oncology Group study

Methods:

Maternally reported congenital abnormalities (CAs) were examined in a case–control study of 278 cases of paediatric germ cell tumours (GCTs) and 423 controls.

Results and conclusions

Germ cell tumours were significantly associated with cryptorchidism in males (OR=10.8, 95% CI: 2.1–55.1), but not with any other specific CA in either sex.

Cryptorchidism and testicular cancer: separating fact from fiction

PURPOSE

We dissected prevailing assumptions about cryptorchidism and reviewed data that support and reject these assumptions.

MATERIALS AND METHODS

Five questions about cryptorchidism and the risk of testicular cancer were identified because of their implications in parent counseling and clinical management. Standard search techniques through MEDLINE were used to identify all relevant English language studies of the questions being examined. Each of the 5 questions was then examined in light of the existing data.

RESULTS

The RR of testicular cancer in a cryptorchidism case is 2.75 to 8. A RR of between 2 and 3 has been noted in patients who undergo orchiopexy by ages 10 to 12 years. Patients who undergo orchiopexy after age 12 years or no orchiopexy are 2 to 6 times as likely to have testicular cancer as those who undergo prepubertal orchiopexy. A contralateral, normally descended testis in a patient with cryptorchidism carries no increased risk of testis cancer. Persistently cryptorchid (inguinal and abdominal) testes are at higher risk for seminoma (74%), while corrected cryptorchid or scrotal testicles that undergo malignant transformation are most likely to become nonseminomatous (63%, p <0.0001), presumably because of a decreased risk of seminoma.

CONCLUSIONS

Orchiectomy may be considered in healthy patients with cryptorchidism who are between ages 12 and 50 years. Observation should be recommended in postpubertal males at significant anesthetic risk and all males older than 50 years. While 5% to 15% of scrotal testicular remnants contain germinal tissue, only 1 case of carcinoma in situ has been reported, suggesting that the risk of malignancy in these remnants is extremely low.

Is increased body mass index associated with the incidence of testicular germ cell cancer?

PURPOSE

Epidemiological and ecological evidences suggest a positive association of overweight and obesity with the risk of testicular germ cell cancer (GCC). Previous controlled trials reported conflicting results. The present study aimed to analyse the putative association of overweight with GCC risk in a large patient sample and to summarize previous data.

METHODS

A total of 8,498 GCC patients were enrolled in a nationwide multicentric case control study. Self-reported body dimensions were recorded for calculation of the body mass index (BMI; kg/m(2)). For comparison, 2,070 age-matched male probands of the latest German National Health Survey (NHS) were employed. Patients and controls were categorized according to age as follows: 18-29, 30-39, and 40-49 years, respectively, and according to BMI, as follows: <18.5; 18.5 to <25; 25 to <30; >30 kg/m(2), respectively. Frequencies of BMI-categories in the three age groups were tabulated and compared statistically. The literature was searched for previous controlled trials regarding BMI and GCC risk.

RESULTS

The median BMI of all GCC patients is 24.69 kg/m(2). Overall comparison of frequencies of BMI categories of cases and controls did not reveal any significant difference. However, in young men (18-29 years) BMI categories 25 to <30 kg/m(2) and >30 kg/m(2) were significantly more frequent in GCC patients than in controls (p < 0.00001). Nineteen previous studies were identified in the literature, one of which being clearly in accordance with the present hypothesis, one being antithetical while the remaining studies were inconclusive in various aspects.

CONCLUSION

The results of this population-based study lend support to two hypotheses regarding the pathogenesis of GCC: First, as high-calorie nutrition is the most important reason for increased BMI, it appears conceivable that nutritional factors are involved in the pathogenesis of GCC. Second, as nonseminoma is the most prevalent histological subtype among younger patients, the association of increased BMI with incidence of GCC in this particular subgroup may point to divergent pathogenetic pathways of nonseminoma and seminoma, respectively.

Methyltertiary-Butyl Ether: Studies for Potential Human Health Hazards

When methyl tertiary-butyl ether (MTBE) in gasoline was first introduced to reduce vehicle exhaust emissions and comply with the Clean Air Act, in the United States, a pattern of complaints emerged characterised by seven "key symptoms." Later, carefully controlled volunteer studies did not confirm the existence of the specific key symptoms, although one study of self-reported sensitive (SRS) people did suggest that a threshold at about 11-15% MTBE in gasoline may exist for SRSs in total symptom scores. Neurobehavioral and psychophysiological studies on volunteers, including SRSs, found no adverse responses associated with MTBE at likely exposure levels. MTBE is well and rapidly absorbed following oral and inhalation exposures. Cmax values for MTBE are achieved almost immediately after oral dosing and within 2 h of continuous inhalation. It is rapidly eliminated, either by exhalation as unchanged MTBE or by urinary excretion of its less volatile metabolites. Metabolism is more rapid humans than in rats, for both MTBE and tert-butyl alcohol (TBA), its more persistent primary metabolite. The other primary metabolite, formaldehyde, is detoxified at a rate very much greater than its formation from MTBE. MTBE has no specific effects on reproduction or development, or on genetic material. Neurological effects were observed only at very high concentrations. In carcinogenicity studies of MTBE, TBA, and methanol (included as an endogenous precursor of formaldehyde, without the presence of TBA), some increases in tumor incidence have been observed, but consistency of outcome was lacking and even some degree of replication was observed in only three cases, none of which had human relevance: alpha(2u)-globulin nephropathy-related renal tubule cell adenoma in male rats; Leydig-cell adenoma in male rats, but not in mice, which provide the better model of the human disease; and B-cell-derived lymphoma/leukemia of doubtful pathogenesis that arose mainly in lungs of orally dosed female rats. In addition, hepatocellular adenomas were significantly higher in female CD-1 mice and thyroid follicular-cell adenomas were increased in female B6C3F1 mice treated with TBA, but these results lack any independent confirmation, which would have been possible from a number of other studies.

Endogenous DNA damage and testicular germ cell tumors

Testicular germ cell tumors are comprised of two histologic groups, seminomas and non-seminomas. We postulated that the possible divergent pathogeneses of these histologies may be partially explained by variable levels of net endogenous DNA damage. To test our hypothesis, we conducted a case-case analysis of 51 seminoma and 61 non-seminoma patients using data and specimens from the Familial Testicular Cancer study and the U.S. Radiologic Technologists cohort. A lymphoblastoid cell line was cultured for each patient and the alkaline comet assay was used to determine four parameters: tail DNA, tail length, comet distributed moment (CDM) and Olive tail moment (OTM). Odds ratios (OR) and 95% confidence intervals (95% CI) were estimated using logistic regression. Values for tail length, tail DNA, CDM and OTM were modelled as categorical variables using the 50th and 75th percentiles of the seminoma group. Tail DNA was significantly associated with non-seminoma compared with seminoma (OR(50th percentile) = 3.31, 95% CI: 1.00, 10.98; OR(75th percentile) = 3.71, 95% CI: 1.04, 13.20; p for trend = 0.039). OTM exhibited similar, albeit statistically non-significant, risk estimates (OR(50th percentile) = 2.27, 95% CI: 0.75, 6.87; OR(75th percentile) = 2.40, 95% CI: 0.75, 7.71; p for trend = 0.12) whereas tail length and CDM showed no association. In conclusion, the results for tail DNA and OTM indicate that net endogenous levels are higher in patients who develop non-seminoma compared with seminoma. This may partly explain the more aggressive biology and younger age-of-onset of this histologic subgroup compared with the relatively less aggressive, later-onset seminoma.

The inguinal canal: anatomy and imaging features of common and uncommon masses

A variety of benign and malignant masses can be found in the inguinal canal (IC). Benign causes of masses in the IC include spermatic cord lipoma, hematoma, abscess, neurofibroma, varicocele, desmoid tumor, air, bowel contrast material, hydrocele, and prostheses. Primary neoplasms of the IC include liposarcoma, Burkitt lymphoma, testicular carcinoma, and sarcoma. Metastases to the IC can occur from alveolar rhabdomyosarcoma, monophasic sarcoma, prostate cancer, Wilms tumor, carcinoid tumor, melanoma, or pancreatic cancer. In patients with a known malignancy and peritoneal carcinomatosis, the diagnosis of metastases can be suggested when a mass is detected in the IC. When peritoneal disease is not evident, a mass in the IC is indicative of stage IV disease and may significantly alter clinical and surgical treatment of the patient. A combination of the clinical history, symptoms, laboratory values, and radiologic features aids the radiologist in accurately diagnosing mass lesions of the IC. Supplemental material available at radiographics.rsnajnls.org/cgi/content/full/28/3/819/DC1.

Trends in testicular germ cell tumours by ethnic group in the United States

The incidence of testicular germ cell tumours (TGCT) has increased in white and black men in the United States. Little is known, however, about trends among men of other racial/ethnic groups. The current study sought to examine TGCT patterns among men of Asian/Pacific Islander/American Indian/ Alaska Native (API/AIAN) and Hispanic ancestries and to determine whether tumours in these groups are diagnosed at comparable stages and sizes to tumours in white and black men. TGCT incidence data and tumour characteristics were drawn from the Surveillance, Epidemiology and End Results registries for two time periods: 1973-2003 and 1992-2003. In 1973-2003, TGCT rates were significantly lower among black (rate ratio = 0.18, p < 0.001) and API/AIAN (rate ratio = 0.37, p < 0.001) men than among white men. Among white and API/AIAN men, rates increased over 60%, mainly prior to 1989-1993. Among black men, rates increased almost 40%, mainly after 1989-1993. Among white and API/AIAN men, increasing proportions of localized disease were diagnosed over time, while the opposite trend was seen among black men. In 1992-2003, TGCT incidence among Hispanic white men (3.46/100 000) was significantly lower than it was among non-Hispanic white men, but rates of both seminoma and non-seminoma increased. While the incidence of TGCT increased among all men, different patterns in the increase were evident. These data suggest that rates are increasing among Hispanic white men and black men, but are stabilizing among white men and API/AIAN men. The peak of the TGCT epidemic may have been reached in these latter groups.

Do testicular seminoma and nonseminoma share the same etiology? Evidence from an age-period-cohort analysis of incidence trends in eight European countries

The incidence of the two main clinical subentities of testicular germ cell cancer (seminoma and nonseminoma) is increasing throughout Europe. Most studies have revealed little variation in risk factors between the two subtypes. This study compared generation-specific trends in eight European countries, hypothesizing that similar temporal pattern by birth cohort implied that seminoma and nonseminoma had a largely comparable etiology. The results are presented using the age-period-cohort model and the nonidentifiability problem highlighted by partitioning the age, period, and cohort effects in terms of their linear and curvature component parts, assuming a priori that cohort effects predominated. Despite uniform overall increases by calendar period, declining rates of nonseminoma but not pure seminoma were observed in the majority of countries during the 1990s. The subtype trends were, however, largely analogous on a birth cohort scale. Notable observations were a decline in rates of both subtypes among recent birth cohorts in Switzerland and a short-term wartime effect in several countries, involving an attenuation of increasing risk of both subtypes in men born in 1940 to 1945. Departures from the steady increases in testicular cancer over time were likely to occur for nonseminomas some years ahead of seminoma on a period scale. The importance of birth cohort coincided with the view that given a short time interval of susceptibility to exposures earlier in life and a biologically constant time to diagnosis, all temporal changes in rate-limiting exposures should appear as generational effects. Trends in seminoma and nonseminoma conform to largely the same temporal patterns on this scale, implying that they share important etiologic factors.

Immunostaining for placental alkaline phosphatase on fine-needle aspiration specimens to detect noninvasive testicular cancer: a prospective evaluation in cryptorchid men

OBJECTIVE

To assess, in a 12-year prospective study, the potential for early detection of testicular carcinoma in situ (CIS) by immunocytochemistry, using anti-placental alkaline phosphatase (PLAP) monoclonal antibodies on testicular fine-needle aspiration cytology (FNAC) specimens taken from a group of formerly cryptorchid patients, as such men are at greater risk of developing testicular cancer.

PATIENTS AND METHODS

Sixty-eight men who had had orchidopexy at the Urological Department of the University of Padova between 1975 and 1983 were evaluated first in 1993, by a protocol including a history, physical examination, testicular ultrasonography and serum tumour markers, to eliminate the presence of testicular cancer. In 57 of the 68 men, specimens taken from bilateral testicular FNAC were stained immunocytochemically using anti-PLAP monoclonal antibodies. After 8 years, the same protocol was repeated on the 57 men, and the follow-up was prolonged until March 2005 for men with previous positive PLAP immunostaining.

RESULTS

In 1993, six of the 57 men, (10.5%) had unilateral positive immunostaining for PLAP. By 2001, none of these men had developed testicular cancer, while of the other 51 men, only one developed a nonseminomatous tumour. The uninterrupted surveillance of PLAP-positive men showed no overt cancer until March 2005.

CONCLUSION

The present findings do not seem to confirm the reliability of PLAP immunostaining of testicular specimens from FNAC for detecting CIS. These findings might depend on the geographical variability of both CIS and testicular cancer incidence, as well as on the variable relationship between CIS and successive occurrence of invasive testis cancer.

Developmental model for the pathogenesis of testicular carcinoma in situ: genetic and environmental aspects

Carcinoma in situ testis (CIS), also known as intratubular germ cell neoplasia (ITGCN), is a pre-invasive precursor of testicular germ cell tumours, the commonest cancer type of male adolescents and young adults. In this review, evidence supporting the hypothesis of developmental origin of testicular germ cell cancer is summarized, and the current concepts regarding aetiology and pathogenesis of this disease are critically discussed. Comparative studies of cell surface proteins (e.g. PLAP and KIT), some of the germ cell-specific markers (e.g. MAGEA4, VASA, TSPY and NY-ESO-1), supported by studies of regulatory elements of the cell cycle (e.g. p53, CHK2 and p19-INK4d) demonstrated a close similarity of CIS to primordial germ cells and gonocytes, consistent with the pre-meiotic origin of CIS. Recent gene expression profiling studies showed that CIS cells closely resemble embryonic stem cells (ESCs). The abundance of factors associated with pluripotency (NANOG and OCT-3/4) and undifferentiated state (AP-2gamma) may explain the remarkable pluripotency of germ cell neoplasms, which are capable of differentiating to various somatic tissue components of teratomas. Impaired gonadal development resulting in the arrest of gonocyte differentiation and retention of its embryonic features, associated with an increasing genomic instability, is the most probable model for the pathogenesis of CIS. Genomic amplification of certain chromosomal regions, e.g. 12p, may facilitate survival of CIS and further invasive progression. Genetic studies, have so far not identified gene polymorphisms predisposing to the most common non-familial testicular cancer, but this research has only recently begun. Association of CIS with other disorders, such as congenital genital malformations and some forms of impaired spermatogenesis, all rising in incidence in a synchronous manner, led to the hypothesis that CIS might be a manifestation of testicular dysgenesis syndrome (TDS). The aetiology of TDS including testicular cancer remains to be elucidated, but epidemiological trends suggest a primary role for environmental factors, probably combined with genetic susceptibility.

Cryptorchidism: an indicator of testicular dysgenesis?

Cryptorchidism is a common ailment of new-born boys, affecting 1-9% of full term boys at birth. Cryptorchidism has been associated with an increased risk of testicular cancer and reduced fertility. Aetiology of cryptorchidism remains obscure in most cases. Familial occurrence suggests a heritable susceptibility to cryptorchidism; however, seasonal variation in the incidence of cryptorchidism suggests that environmental factors also contribute. Testicular descent is characterised by androgen-dependent regression of cranial suspensory ligament and androgen + insulin-like hormone 3 (Ins l3)-dependent gubernacular outgrowth. Even though hormonal defects are rarely detected in patients, both hypo-and hypergonadotropic hormonal patterns have been associated with cryptorchidism. Moreover, cryptorchid boys have significantly reduced serum androgen bioactivity at 3 months of age when normal boys have a strong surge of reproductive hormones. Defects in Ins l3 action cause cryptorchidism in male mice, and over-expression in female mice causes ovarian descent. Defects in leucine-rich repeat-containing G-protein-coupled receptor 8/G-protein-coupled receptor affecting testis descent (LGR8/GREAT), the receptor for Ins l3, manifest the same phenotype as Ins l3 knockout mutants. Even though mutations found in Ins l3 and LGR8/GREAT genes are not a common cause of cryptorchidism in patients, it remains to be resolved whether low Ins l3 levels during development are associated with cryptorchidism. Cryptorchidism may reflect foetal testicular dysgenesis that may later manifest as subfertility or testicular cancer.

The changing presentation of germ cell tumours of the testis between 1983 and 2002

OBJECTIVE

To prospectively investigate the presentation of germ cell tumours (GCTs) of the testis in terms of stage or histology, as the incidence of this disease in increasing.

PATIENTS AND METHODS

Patients diagnosed with GCT of the testis between 1983 and 2002 were categorised into three periods depending on the date of diagnosis of the GCT, and the presentational characteristics assessed. RESULTS There was a significant increase in the proportion of patients presenting with stage I disease (59% to 78%) and seminoma (43% to 58%) over this period. There was also a significant reduction in the size of the primary tumour (5 to 4 cm).

CONCLUSION

A greater proportion of patients with GCT are presenting with stage I seminoma, the reasons for which are unclear, although earlier diagnosis through improved awareness of GCT may be important.

Origins and molecular biology of testicular germ cell tumors

Testicular germ cell tumors can be divided into three groups (infantile/prepubertal, adolescent/young adult and spermatocytic seminoma), each with its own constellation of clinical histology, molecular and clinical features. They originate from germ cells at different stages of development. The most common testicular cancers arise in postpubertal men and are characterized genetically by having one or more copies of an isochromosome of the short arm of chromosome 12 [i(12p)] or other forms of 12p amplification and by aneuploidy. The consistent gain of genetic material from chromosome 12 seen in these tumors suggests that it has a crucial role in their development. Intratubular germ cell neoplasia, unclassified type (IGCNU) is the precursor to these invasive tumors. Several factors have been associated with their pathogenesis, including cryptorchidism, elevated estrogens in utero and gonadal dysgenesis. Tumors arising in prepubertal gonads are either teratomas or yolk sac tumors, tend to be diploid and are not associated with i(12p) or with IGCNU. Spermatocytic seminoma (SS) arises in older patients. These benign tumors may be either diploid or aneuploid and have losses of chromosome 9 rather than i(12p). Intratubular SS is commonly encountered but IGCNU is not. The pathogenesis of prepubertal GCT and SS is poorly understood.

Epidemiology of testicular cancer: An overview

Testicular cancer is a rare disease, accounting for 1.1% of all malignant neoplasms in Canadian males. Despite the low overall incidence of testicular cancer, it is the most common malignancy among young men. The incidence rate of testicular cancer has been increasing since the middle of the 20th century in many western countries. However, the etiology of testicular cancer is not well understood. A search of the peer-reviewed literature was conducted to identify important articles for review and inclusion in this overview of the epidemiology of testicular cancer. Most of the established risk factors are related to early life events, including cryptorchidism, carcinoma in situ and in utero exposure to estrogens. Occupational, lifestyle, socioeconomic and other risk factors have demonstrated mixed associations with testicular cancer. Although there are few established risk factors for testicular cancer, some appear to be related to hormonal balance at various life stages. Lifestyle and occupational exposures occurring later in life may play a role in promoting the disease, although they are not likely involved in cancer initiation. In addition to summarizing the current epidemiologic evidence on risk factors for testicular cancer, we suggest future research directions that may elucidate the etiology of testicular cancer.

Testicular Cancer Incidence in Eight Northern European Countries: Secular and Recent Trends

Objective: Striking geographic variation and marked increasing secular trends characterize the incidence of testicular cancer. However, it is not known whether these patterns have attenuated in recent years and whether they are similar for seminomas and nonseminomas, the two main histologic groups of testicular cancer.

Method: Cancer registry data, including 27,030 testicular cancer cases, were obtained from Denmark, Estonia, Finland, Latvia, Lithuania, Norway, Poland, and Sweden. Between 57 (Denmark) and 9 (Poland) years of registration were covered. Country-specific temporal trends were estimated, with focus on the last decade and seminomas and nonseminomas. Data from the Nordic countries were further analyzed using an age-period-cohort approach.

Results: Age-standardized incidence rates increased annually by 2.6% to 4.9% during the study period, with marginal differences between seminomas and nonseminomas. In the last decade, the increasing trend attenuated only in Denmark (annual change, −0.3%; 95% confidence interval, −1.5 to 0.9). In 1995, the highest and the lowest age-standardized incidence rates (per 105) were 15.2 in Denmark and 2.1 in Lithuania. Incidence rates (i.e., for all cancers and for seminomas and nonseminomas, separately) depended chiefly on birth cohort rather than on calendar period of diagnosis (although both birth cohort and period determined the Danish incidence rates).

Conclusions: Testicular cancer incidence is still increasing, with the exception of Denmark, and a large geographic difference exists. The increasing trend is mainly a birth cohort phenomenon also in recent cohorts. Temporal trends for seminomas and nonseminomas are similar, which suggests that they share important causal factors.

Cancers of the prostate, penis, and testicles: epidemiology, prevention, and treatment

Cancer is a disease that most people fear. Nurses are required to provide information on how to avoid cancer, and, once the diagnosis is made, how to cope with it. Prevention and early detection of the cancers described in this article are in the very early stages of knowledge development, but general health promotion guidance can be offered on how to avoid most cancers (ie, no tobacco use, a high-fiber and low fat diet, exercise, and maintaining a normal weight). Nurses also can advise patients to be screened for colorectal cancer at the appropriate ages and time intervals and to be aware as new developments occur in the scientific base for screenings in the areas of prostate, penile, and testicular cancer. Finally, coping with these forms of cancer often requires the patient to make major lifestyle and psychological changes, especially if surgery in the genital area occurs. Decreased libido, incontinence, and impotence are major complications that can occur with these illnesses. The male cancers described vary tremendously in their prevalence, incidence, mortality, treatment, and survival rates. Within this group, there are remarkably positive outcomes and outcomes much in need of improvement. Penile and testicular cancers are the bright spots in this picture; both are uncommon, and both are eminently treatable. Prostate cancer, on the other hand, is quite common, difficult to screen, difficult to treat without major sexual problems, and yet receives relatively little funding from the NIH. Although as many men die from prostate cancer as women die from breast cancer, NIH funds breast cancer research at much higher levels than prostate cancer. According to the latest data available at the NIH Web site, during the 1990s, the amount of NIH funding varied from four times more for breast cancer (1993) to 2.9 times more in 1999. For fiscal year 2002, NIH is providing $522 million in funding for breast cancer and $278 million for prostate cancer. Private foundation funds for prostate cancer are much smaller than those available for breast cancer. Both types of cancer are extremely important to address, and both should receive adequate research attention. Nurses can advocate for more funding for prostate cancer, from basic science approaches to behavioral science strategies.

Management of recurrence and follow-up strategies for patients with seminoma and selected high-risk groups

Seminoma is characterized by high sensitivity to both radiation and chemotherapy. Localized recurrences in the retroperitoneum after surveillance for stage I can be treated with radiotherapy; however, multiple or large bulky retroperitoneal recurrences or systemic metastasis requires cisplatin-based chemotherapy. Salvage chemotherapy for those who recur after initial CR to induction chemotherapy is based on ifosfamide- and cisplatin-containing regimens. Incomplete response or failure after induction chemotherapy requires high-dose chemotherapy and stem cell rescue. Patients with seminoma need long-term follow-up because of the possibility of late recurrence and the risk of a second primary tumor.

Dietary risk factors for testicular carcinoma

Although testicular cancer is a relatively rare lesion, accounting for only 1.1% of all malignant neoplasms in males in Canada, it is the most common cancer among Canadian men 20-45 years of age. Knowledge of the causes of testicular cancer risk in general, and more specifically, its association with diet, remain limited. Data from 601 cases of testicular cancer and 744 population-based controls collected in 8 of the 10 Canadian provinces between 1994-97 were used to explore the relationship between diet and testicular cancer risk. We systematically examined 17 food groups, 15 nutrients and 4 individual foods based on data collected through a 69-item food-frequency questionnaire. Our results suggest that high dairy product intake, in particular high intake of cheese (odds ratio [OR] = 1.87; 95% confidence interval [CI] 1.22-2.86; p-trend < 0.001), is associated with an elevated risk of testicular cancer in Canadian males.

Trends in testicular cancer incidence in Vaud, Switzerland

Upward trends in testicular cancer incidence have been reported in Europe and North America, particularly for seminomas. We considered incidence data between 1974 and 1999 from the Swiss cancer registry of Vaud, i.e. one of the highest incidence areas on a worldwide scale, including a total of 731 cases. Testicular cancer incidence was around 8.5/100 000 between the mid-1970s and the late 1980s, and increased to around 10/100 000 in the 1990s. Corresponding figures at age 15-44 were around 16/100 000 between the mid-1970s and the late 1980s, and about 19/100 000 thereafter. No evidence of persisting upward trends was evident over the last few years. The rise in testicular cancer incidence in the 1990s was apparently restricted to seminomas, whose rates increased from about 4 to 5.7/100 000 at all ages, and from 7 to over 11/100 000 at age 15-44. No consistent pattern of trends was observed for malignant teratomas and for other and unspecified histotypes. Testicular cancer in Vaud has shown no tendency to further rising over the last decade, thus re-opening the issue of a probable asymptote of testicular cancer incidence in this population.

Trends in the incidence of testicular germ cell tumors in the United States

BACKGROUND

Recent reports have suggested that the increasing rates of testicular germ cell tumors in some populations have begun to plateau. This study was conducted to examine whether rates among white men in the United States have begun to stabilize and whether rates among black men in the United States have remained low.

METHODS

Testicular germ cell tumor incidence data from in the Surveillance, Epidemiology, and End Results Program were analyzed for the years 1973-1998. Trends were examined separately for seminoma and nonseminoma. Using age-period-cohort analyses with 5-year age intervals and 5-year calendar-period intervals, changes in the slope of the trends in birth-cohort and calendar-period effects were examined.

RESULTS

Among white men, rates of seminoma continued to increase, but the rate of increase steadily declined throughout the 26-year time span. Nonseminoma rates among whites increased more slowly during the first three time intervals, then plateaued in the final interval. Rates of both seminoma and nonseminoma in black men fluctuated throughout the first three time intervals. In the final interval, the rates of seminoma increased almost 100%, whereas the rates of nonseminoma increased more modestly. Age-period-cohort modeling of the incidence data in white men found that, whereas the dominant effect was that of birth cohort, there also was a period effect.

CONCLUSIONS

Among white men in the United States, the incidence of testicular germ cell tumors varied by histology, with a continuing increase in risk only for seminoma. Among black men in the United States, the surprising increases seen between 1988 and 1998 were likely to be a calendar-period effect.

Genetics and biology of male germ cell tumors

The application of cytogenetic and molecular genetic techniques to the study of germ cell tumors has yielded many clues to the etiology and chemosensitivity of these tumors. With the advent of expression profiling and genome-scanning technologies, it may be possible to identify molecular markers of germ cell tumor outcome and molecular networks important in human development and chemotherapeutic response.

Epidemiology of cancer in adolescents

In western populations, the annual incidence rate of cancer among adolescents aged 15-19 years is around 150-200 per million, intermediate between the rates for older children and young adults. The most frequent diagnostic groups are acute leukemia, lymphomas, central nervous system tumors, bone and soft tissue sarcomas, germ cell tumors, thyroid carcinoma, and malignant melanoma. While the causes of most cancers in teenagers are still unknown, health education and promotion and public health programs offer some scope for prevention among people of this age group. Reduction in sun exposure should lead to a reduction in incidence of melanoma, and elimination of hepatitis B in regions where it is endemic should result in a decrease in hepatic carcinoma. Five-year survival of patients diagnosed around 1990 exceeded 70% in the USA and UK. Entry to clinical trials appears to be much less frequent for adolescents with cancer than for children. There is some evidence that higher survival is associated with entry to trials or centralized treatment for certain cancers in this age group.