Time trends in Hodgkin's disease incidence. The role of diagnostic accuracy

Global, regional, and national burden of Hodgkin lymphoma from 1990 to 2017: estimates from the 2017 Global Burden of Disease study

Background

Hodgkin lymphoma (HL) is an uncommon B cell lymphoma. We assessed the global, regional, and national burden of HL from 1990 to 2017, by gender, age, and social-demographic index (SDI).

Methods

Data on HL, including incidence, mortality, and disability adjusted life-years (DALY), from 1990 to 2017 were obtained from the 2017 Global Burden of Disease study. Estimated annual percentage changes (EAPCs) were calculated to assess incidence rate, mortality, and DALY trends.

Results

HL incidences increased by 38.66%, from 72,937 in 1990 to 101,133 in 2017, while the age-standardized incidence rate (ASIR) was relatively stable. ASIR decreased in the low SDI regions (EAPC = − 2.58; 95% CI, from − 2.66 to − 2.49) and was stable in the other four SDI regions. Incidence showed a bimodal distribution with peak values in patients aged 20–39 years and patients aged 60 years or higher. The number of death cases and DALYs were stable. The age-standardized death rate decreased by 2.36% (95% CI, from − 2.43% to − 2.30%) per year. The annual age-standardized DALY rate decreased by 2.29% (95% CI, from − 2.36% to − 2.21%). The incidence and mortality in male subjects was higher than that in female subjects. The incidence in male and female subjects aged 15–30 years old was close, whereas the biggest difference existed in patients aged < 10 years old and 45–75 years old between genders.

Conclusion

Globally, incidence of HL was stable, while mortality and DALY rate of HL had been decreasing from 1990 to 2017. Compared with lower and decreasing ASIR in the low SDI region, ASIR in the high SDI region was always high, indicating the need for HL treatment improvement and the establishment of more targeted and specific strategies in high SDI countries to reduce the incidence of HL.

Health Disparities and the Global Landscape of Lymphoma Care Today

Lymphoma encompass a wide variety of distinct disease entities, including, but not limited to, subtypes of non-Hodgkin lymphoma (NHL) and Hodgkin lymphoma (HL). In the last 3 decades, therapeutic advancements have resulted in substantial improvements in lymphoma outcome. In most high-income regions, HL is a largely curable disease and for patients with two frequent subtypes of NHL, diffuse large B-cell lymphoma (DLBCL) and follicular lymphoma (FL), survival has dramatically improved with the incorporation of rituximab as a standard treatment approach. Despite these advances, outcomes vary between and across populations. This review will provide updated information about health disparities in lymphoma in the United States and across the globe.

The increasing toll of adolescent cancer incidence in the US

Cancer incidence is rising among adolescents (“teens”). The causes of the increase are unknown but studying incidence patterns and trends may produce insights into etiology. Using data from the US National Cancer Institute’s Surveillance, Epidemiology, and End Results (SEER) program we described trends of cancer incidence among teens (15–19 year olds). We reviewed and summarized incidence patterns for histologic cancer groups and the most frequently diagnosed sites of cancer among teens during 2008–2012 reported by the SEER Cancer Statistics Review. We calculated annual incidence rates for the years 1975–2012 and used linear regression analysis to evaluate trends and calculate rates of change. Incidence for all sites combined increased annually by 0.67% for males and 0.62% for females during the period 1975 through 2012 –resulting in more than a 25% increase over 38 years. The biggest annual incidence increases occurred in non-Hodgkin lymphoma (NHL) (2.16% females; 1.38% males), thyroid cancer (2.12% females; 1.59% males), acute myeloid leukemia (AML) (1.73% females) and testicular cancer (1.55% males). Incidence rates for most histologic groups and sites showed steady long term increases over the 38 years of data. Despite improvements in survival, rising incidence trends mean growing numbers of young adults are undergoing painful and costly cancer treatments. A concerted research program is vital to investigate causes of steadily rising teen cancer rates.

Hodgkin lymphoma burden in Central and South America

RATIONALE AND OBJECTIVE

Hodgkin lymphoma (HL) is largely curable owing to improvements in treatment since the 1960s; nevertheless, high mortality rates have been reported in Central and South America. We describe the current burden of HL in the Central and South American region.

METHODS

We obtained regional- and national-level incidence data from 48 population-based cancer registries in 13 countries, and national-level mortality data from the WHO mortality database for 18 countries. We estimated world population age-standardized incidence rates (ASRs) and age-standardized mortality rates (ASMRs) per 100,000 person-years for 2003-2007 and present distributions by histological subtype.

RESULTS

HL incidence rates varied 7-fold in males and 11-fold in females (male-to-female ratio 1:1-2.5:1). The highest ASRs were seen Argentina, Brazil, Costa Rica (males), Cuba (males) and Uruguay (females), whereas the lowest were in Bolivia and El Salvador. ASMRs varied by 4-fold in males and 6-fold in females (male-to-female ratio 1:1-4.3:1), with ASMRs <0.7 for most countries, except Cuba (≥1.0). In most countries, age-specific incidence rates of HL showed a bimodal pattern. Trends in HL in Argentina, Brazil, Chile, and Costa Rica remained stable in 1997-2008. Of all HL cases, 48% were unspecified as to histological subtype. Nodular sclerosis and mixed cellularity were the most frequent histologies.

CONCLUSION

The geographic variation in HL across the region may in part reflect differences in data quality and coverage, and differences in the adoption of modern therapies and healthcare access. Our results highlight the need for high-quality data and increased coverage in order to provide vital guidance for future cancer control activities.

Time Trends in Rates of Hodgkin Lymphoma Histologic Subtypes: True Incidence Changes or Evolving Diagnostic Practice?

BACKGROUND

Histologic subtypes of classical Hodgkin lymphoma [cHL; e.g., nodular sclerosis, mixed cellularity, not otherwise specified (NOS)] are epidemiologically and prognostically distinctive. Therefore, unexplained, ongoing incidence rate declines for mixed cellularity and increases for NOS require examination.

METHODS

We analyzed detailed histology-specific Hodgkin lymphoma incidence rates in 1992 through 2011 U.S. SEER data (n = 21,372) and reviewed a regional subset of 2007 through 2011 NOS pathology reports for insight into diagnostic practices.

RESULTS

cHL rates were stable until 2007, then decreased for whites [annual percent change (APC) and 95% confidence interval (CI), -3.6% (-5.6% to -1.5%)]. Nodular sclerosis rates declined after 2007 by 5.9% annually, with variation by gender, age, and race/ethnicity. In 1992 through 2011, mixed cellularity rates declined [APC -4.0% (-4.7% to -3.3%)], whereas NOS rates rose [5.3% (4.5%-6.2%)] overall and in most patient groups. The 2007-2011 NOS age-specific rates were more similar to mixed cellularity rates for 1992-1996 than 2007-2011. Trends in combined rates were minimal, supporting increasing misclassification of mixed cellularity, lymphocyte depletion, and specific nodular sclerosis subtypes as NOS. Eighty-eight of 165 reviewed NOS pathology reports addressed classification choice. Twenty (12.1%) justified the classification, 21 (12.7%) described insufficient biopsy material, and coders missed specific subtype information for 27 (16.4%).

CONCLUSION

Recent nodular sclerosis rate declines largely represent true incidence changes. Long-term rate decreases for mixed cellularity and other less common subtypes, and increases for NOS (comprising ∼30% of cHL cases in 2011), likely reflect changes in diagnostic and/or classification practice.

IMPACT

Diminishing histologic subtyping undermines future surveillance and epidemiologic study of Hodgkin lymphoma. Guideline-based use of excisional biopsies and more coding quality control are warranted.

DNA methylation patterns in EBV-positive and EBV-negative Hodgkin lymphomas

PURPOSE

Hodgkin lymphoma (HL) is characterized by the presence of Hodgkin and Reed-Sternberg cells. Epstein-Barr virus (EBV) infection is thought to play an important role in the development of HL. Although epigenetic alterations, such as aberrant DNA methylation, are known to contribute to the pathogenesis of various malignancies, little is known about such alterations in HL and their putative relationships with EBV infection.

METHODS

We investigated promoter methylation patterns of seven tumor-associated genes in 53 primary HL cases using methylation-specific PCR (MS-PCR). Concomitantly, the EBV infection status was assessed using PCR, in situ hybridization and immunohistochemistry.

RESULTS

The gene promoter hypermethylation frequencies observed were 77.3 % for P16, 58.5 % for RASSF1A, 50.9 % for CDH1, 45.3 % for DAPK, 43.4 % for GSTP1, 37.7 % for SHP1 and 24.3 % for MGMT. SHP1 gene promoter hypermethylation was more frequently observed in patients at extreme ages (i.e., ≤ 15 and >54 years) than in adult patients (p = 0.006) and in patients with B symptoms (p = 0.03). Interestingly, most of the analyzed gene promoters were more frequently hypermethylated in EBV-negative than in EBV-positive cases, in particular the DAPK gene promoter (58 % versus 27 %, p = 0.04). Furthermore, hypermethylation of multiple gene promoters (≥ 3) was encountered more frequently in females than in males (86 % versus 57 %, p = 0.04), whereas EBV-positive cases were more common among males than females (55 % versus 30 %, p = 0.02).

CONCLUSIONS

Our results indicate that epigenetic changes frequently occur in both EBV-positive and EBV-negative HL. The rates of these changes were found to vary according to clinico-pathological parameters. These observations probably reflect the multitude of factors involved in HL development and the complexity of their interactions with genetic and/or hormonal factors.

Different time trends by gender for the incidence of Hodgkin's lymphoma among young adults in the USA: a birth cohort phenomenon

OBJECTIVES

Hodgkin's lymphoma (HL) is one of the most common cancers among young adults. We investigated the time trends for HL among the 20-44 age group in the USA by gender to identify the potential factors accounting for the incidence trends.

METHODS

Using data from the National Cancer Institute's Surveillance, Epidemiology, and End Results program for 1973-2010, we conducted age-period-cohort modeling to evaluate birth cohort patterns on incidence trends of HL over time.

RESULTS

For all races combined, the age-adjusted incidence patterns were similar to that of whites. The birth cohort patterns for whites and all races were similar, but the patterns differed according to gender. Specifically, except for the 1970-1975 birth cohort, all other birth cohorts showed an increasing birth cohort trend for females. Conversely, there was a decreasing cohort trend in males beginning in the 1960 birth cohort regardless of the assumptions of the period effect.

CONCLUSION

The established risk factors for HL can seemingly not explain the gender disparities of the cohort pattern, which necessitates further analytical epidemiological studies to explore the risk factors for this disease with respect to potential differences by gender and by histological subtype.

A collaborative nationwide lymphoma study in Lebanon: incidence of various subtypes and analysis of associations with viruses

Incidence of various Hodgkin (HL) and non-Hodgkin lymphoma (NHL) subtypes and association with viruses in Lebanon are not known. We undertook a nationwide study of 272 patients diagnosed with lymphoma in 2007. HL comprised 32.7 % (n = 89) of cases while NHL represented 67.3 % (n = 183). Consistent with the literature, nodular sclerosis was the most predominant HL subtype (n = 57/89). Among NHL, B-cell NHL represented 88 % (n = 161/183), T-cell NHL 9 % (n = 17/183), whereas in 2.7 % it was not classifiable. The B-cell NHL comprised predominantly diffuse large B-cell lymphoma (46 %) and follicular lymphoma (23 %). 81 cases were reviewed by a panel of pathologists with 87.6 % concordance rate. Serology was negative for hepatitis C in 122 tested cases. HIV was positive in 2 cases. Two adult T-cell leukemia/lymphoma were HTLV-I positive. EBV IgG were positive in 88.5 % of cases. 38 EBV seropositive cases [27 NHL (24 B-cell, 3 T-cell) and 11 HL] were studied for EBV genome expression using EBV-encoded RNA (EBER)-in situ hybridization. EBER expression was positive in 8 (21 %) cases (6 HL, 2 T-cell NHL). The distribution of lymphoma subtypes in Lebanon appears similar to that of Western countries. The high rate of EBV positivity in HL and T-cell lymphoma by EBER deserves further investigation.

Subtype of dietary fat in relation to risk of Hodgkin lymphoma: a population-based case-control study in Connecticut and Massachusetts

Few epidemiological studies have examined the relationship between dietary fat, which may affect immune function and risk of Hodgkin lymphoma (HL). The aim of this study was to test the hypothesis that high dietary intake of fat and specific subtypes of fat is associated with the risk of HL among 486 HL cases and 630 population-based controls recruited between 1997 and 2000 in Connecticut and Massachusetts. Unconditional logistic regression was used to calculate odds ratios (ORs) and 95 % confidence intervals (CIs) stratified by age and gender. Among younger adults, HL risk was significantly and positively associated with higher intake of saturated fat [ORs for increasing quartiles = 1.3, 1.8, and 2.1; p trend = 0.04] and negatively associated with higher intake of monounsaturated fat [ORs for increasing quartiles = 0.5, 0.5, and 0.4; p trend = 0.03), after adjustment for potential confounders including lifestyle and other dietary factors. The associations with saturated fat (ORs for increasing quartile = 2.4, 3.2, and 4.4; p trend < 0.01] and monounsaturated fat (ORs for increasing quartile = 0.3, 0.6, and 0.3; p trend = 0.04) were most apparent in younger women, whereas there was no significant association between intake of total fat or any type of fat and risk of HL in older females or younger or older males. These findings show that the associations between dietary fat and risk of HL may vary by gender and age and require confirmation in other populations.

Body size and risk of Hodgkin's lymphoma by age and gender: a population-based case-control study in Connecticut and Massachusetts

PURPOSE

Descriptive studies have indicated a rising trend in Hodgkin's lymphoma (HL) incidence in young adults, especially females. Increasing evidence has suggested that some risk factors associated with HL may vary by age or gender. Recent studies have reported an increased risk of HL associated with increasing body mass index (BMI), but the results have been inconsistent. The objectives of this study were to examine whether the associations between measures of body size (height, weight, and BMI) and HL risk vary by age and/or gender.

METHODS

A population-based case-control study was conducted in Connecticut and Massachusetts. A total of 567 HL cases and 679 controls were recruited in 1997-2000. Unconditional logistic regression was used to calculate odds ratios (ORs) and 95 % confidence intervals (CIs).

RESULTS

Among younger women <35 years old, being overweight (25-29.9 kg/m(2)) versus normal weight (18.5-24.9 kg/m(2)) was significantly associated with an increased risk of HL (OR = 2.1, 95 % CI = 1.1-4.0). The risk increased with increasing weight and BMI (p trends <0.01). Among women ≥35 years old, by contrast, higher weight and BMI were associated with a reduced risk of HL (p trends <0.01). Conversely, there was no significant association between BMI and risk of HL in younger or older males.

CONCLUSIONS

These findings show that the associations between body size and risk of HL vary by gender and age, and require confirmation in other populations.

International Prognostic Score in advanced-stage Hodgkin's lymphoma: altered utility in the modern era

PURPOSE

The International Prognostic Score (IPS) is the most widely used risk stratification index for Hodgkin's lymphoma (HL). It is based on patients treated before 1992 and predicts 5-year freedom from progression (FFP) and overall survival (OS) ranging from 42% to 84% and 56% to 89%, respectively. The IPS has not been validated in a recently treated population in which outcomes have improved compared with historic results.

PATIENTS AND METHODS

By using the British Columbia Cancer Agency Lymphoid Cancer Database, we identified all patients age ≥ 16 years newly diagnosed with advanced-stage HL (stage III to IV, or stage I to II with "B" symptoms or bulky disease ≥ 10 cm) from 1980 to 2010, treated with curative intent with doxorubicin, bleomycin, vinblastine, and dacarbazine (ABVD) or an ABVD-equivalent regimen with complete clinical information.

RESULTS

In all, 740 patients were identified. Five-year FFP and OS were 78% and 90%, respectively. The IPS was prognostic for both FFP (P < .001) and OS (P < .001), with 5-year FFP ranging from 62% to 88% and 5-year OS ranging from 67% to 98%. Analysis limited to patients age 16 to 65 years (n = 686) demonstrated a narrower range of outcomes, with 5-year FFP ranging from 70% to 88% and 5-year OS ranging from 73% to 98%.

CONCLUSION

The IPS remains prognostic for advanced-stage HL, but the range of outcomes has narrowed considerably. This improvement in outcome with ABVD should be acknowledged before consideration of alternate initial therapies and when comparing results from current trials with those of historic controls.

Racial disparities in Hodgkin's lymphoma: a comprehensive population-based analysis

BACKGROUND

Racial disparity has been investigated in a number of cancers; however, there remains a comparative paucity of data in Hodgkin's lymphoma (HL).

PATIENTS AND METHODS

We examined time-, age-, and gender-specific incidence, disease characteristics, and survival across and within races for adolescent/adult HL (age 10-79 years) diagnosed during 1992-2007 in the SEER 13 registries.

RESULTS

A total of 15 662 HL cases were identified [11,211 non-Hispanic whites, 2067 Hispanics, 1662 blacks, and 722 Asian/Pacific Islanders (A/PI)]. Similar to whites, A/PIs had bimodal age-specific incidence, while blacks and Hispanics did not. Further, HL was significantly more common in Hispanics versus whites age>65 years (7.0/1×10(6) versus 4.5/1×10(6), respectively, P<0.01). By place of birth, US-born Hispanics and A/PIs age 20-39 years had higher incidence of HL versus their foreign-born counterparts (P<0.05), however, rates converged age>40 years. Interestingly, from 1992-1997 to 2003-2007, A/PI incidence rates increased >50% (P<0.001). Moreover, this increase was restricted to US-born A/PI. We also identified a number of disease-related differences based on race. Finally, 5-, 10-, and 15-year overall survival rates were inferior for blacks and Hispanics compared with whites (P<0.005 and P<0.001, respectively) and A/PI (P<0.018 and P<0.001, respectively). These differences persisted on multivariate analysis.

CONCLUSION

Collectively, we identified multiple racial disparities, including survival, in adolescent/adult HL.

Epidemiologic overview of malignant lymphoma

Malignant lymphoma encompasses a wide variety of distinct disease entities. It is generally more common in developed countries and less common in developing countries. The East Asia region has one of the lowest incidence rates of malignant lymphoma. The incidence of malignant lymphoma around the world has been increasing at a rate of 3-4% over the last 4 decades, while some stabilization has been observed in developed countries in recent years. The reasons behind this lymphoma epidemic are poorly understood, although improving diagnostic accuracy, the recent AIDS epidemic, an aging world population and the increasing adoption of cancer-causing behaviors are suggested as contributing factors. Etiologies of malignant lymphoma include infectious agents, immunodeficiency, autoimmune disease, exposure to certain organic chemicals, and pharmaceuticals. The distribution of many subtypes exhibit marked geographic variations. Compared to the West, T/natural killer (NK) cell lymphomas (T/NK-cell lymphoma) and extranodal marginal zone lymphoma of mucosa-associated lymphoid tissue (MALT lymphoma) are relatively more common, whereas other B-cell lymphomas, particularly follicular lymphoma and chronic lymphocytic leukemia/small lymphocytic lymphoma, are less common in Asia. Some subtypes of T/NK-cell lymphomas defined by Epstein-Barr virus association are predominantly Asian diseases, if not exclusively so. Both ethnic and environmental factors play roles in such diversity. In this review, we discuss the geographic distribution and etiology of malignant lymphoma, as well as the trend.

Changing patterns of Hodgkin lymphoma incidence in Singapore

A bimodal age-specific incidence pattern with a relatively high proportion of cases occurring in adolescents and young adults is a hallmark of Hodgkin lymphoma (HL) epidemiology in Western industrialized countries. The young adult incidence peak is believed to reflect the association between HL risk in young adults and an affluent childhood socioeconomic environment. However, the dynamic development of the young adult incidence peak following socioeconomic development implied by this interpretation has scarcely been demonstrated in a single population over time. We, therefore, analyzed incidence patterns of HL in Singapore between 1968 and 2004, during which time period a socioeconomic transition towards Western World lifestyles took place. As hypothesized a HL incidence peak emerged among adolescents and young adults in Singapore. Thus, in the age groups 15-19 and 20-24 years incidence rates increased annually by 7.0% (95% confidence interval 3.4%-10.7%) and 3.4% (0.1%-6.8%), respectively, in men and by 13.7% (9.1%-18.6%) and 12.2% (7.8-16.8%), respectively, in women between 1968 and 2004. However, the incidence peak remained considerably lower than what can be observed in young adults in the Western World. It remains to be determined to what extent the current lower incidence of HL in young Asian adults should be attributed to birth cohort phenomena, as would be suggested by continued increase in incidence, and to ethnic variation in HL susceptibility between Asian and non-Asian populations, respectively.

Cigarette smoking and risk of Hodgkin lymphoma: a population-based case-control study

BACKGROUND

Studies have inconsistently reported an association between tobacco smoking and Hodgkin lymphoma (HL) risk. The conflicting finding may reflect etiologic heterogeneity between HL subtypes, warranting further characterization of the relationship.

METHODS

We collected information on tobacco-smoking habits in 586 classic HL cases and 3,187 population controls in a Danish-Swedish case-control study. HL EBV status was established for 499 cases by standard techniques. Odds ratios (OR) for an association with cigarette smoking were calculated by logistic regression for HL overall and stratified by age, sex, major histology subtypes, and tumor EBV status, adjusting for known confounders.

RESULTS

Compared with never smokers, current cigarette smokers were at an increased overall HL risk [adjusted OR, 1.57; 95% confidence interval (95% CI), 1.22-2.03]. The association was strongest for EBV-positive HL (adjusted OR, 2.36; 95% CI, 1.51-3.71), but also applied to EBV-negative HL (adjusted OR, 1.43; 95% CI, 1.05-1.97; P(homogeneity EBV-pos) versus P(homogeneity EBV-neg) = 0.04). The association did not vary appreciably by age, sex, or histologic subtype, the apparent EBV-related difference present in all strata. There was no evidence of a dose-response pattern, whether by age at smoking initiation, daily cigarette consumption, number of years smoking, or cumulative number of cigarettes smoked. Similar results were obtained in analyses using non-HL patients (n = 3,055) participating in the founding study as comparison group.

CONCLUSION

The observed association between cigarette smoking and HL risk is consistent with previous findings and biologically credible. Although not easily dismissed as an artifact, the limited evidence of a dose-response pattern renders the overall evidence of causality weak.

Malignant lymphomas in autoimmunity and inflammation: a review of risks, risk factors, and lymphoma characteristics

Certain autoimmune and chronic inflammatory conditions, such as Sjögren's syndrome and rheumatoid arthritis (RA), have consistently been associated with an increased risk of malignant lymphomas, but it is unclear whether elevated lymphoma risk is a phenomenon that accompanies inflammatory conditions in general. Likewise, it is debated whether the increased risk identified in association with some disorders pertains equally to all individuals or whether it varies among groups of patients with different phenotypic or treatment-related characteristics. It is similarly unclear to what extent the increased lymphoma occurrence is mediated through specific lymphoma subtypes. This update reviews the many findings on risks, risk levels, and lymphoma characteristics that have been presented recently in relation to a broad range of chronic inflammatory, including autoimmune, conditions. Recent results clearly indicate an association between severity of chronic inflammation and lymphoma risk in RA and Sjögren's syndrome. Thus, the average risk of lymphoma in RA may be composed of a markedly increased risk in those with most severe disease and little or no increase in those with mild or moderate disease. The roles of immunosuppressive therapy and EBV infection seem to be limited. Furthermore, RA, Sjögren's syndrome, systemic lupus erythematosus, and possibly celiac disease may share an association with risk of diffuse large B-cell lymphoma, in addition to well-established links of Sjögren's syndrome with risk of mucosa-associated lymphoid tissue lymphoma and of celiac disease with risk of small intestinal lymphoma. However, there is also obvious heterogeneity in risk and risk mediators among different inflammatory diseases.

Lymphoma incidence patterns by WHO subtype in the United States, 1992-2001

Because the causes of most lymphoid neoplasms remain unknown, comparison of incidence patterns by disease subtype may provide critical clues for future etiologic investigations. We therefore conducted a comprehensive assessment of 114,548 lymphoid neoplasms diagnosed during 1992-2001 in 12 Surveillance, Epidemiology, and End Results (SEER) registries according to the internationally recognized World Health Organization (WHO) lymphoma classification introduced in 2001. Cases coded in International Classification of Diseases for Oncology, Second Edition (ICD-O-2), were converted to ICD-O-3 for WHO subtype assignment. Age-specific and age-adjusted rates were compared by sex and race (white, black, Asian). Age-adjusted trends in incidence were estimated by sex and race using weighted least squares log-linear regression. Diverse incidence patterns and trends were observed by lymphoid neoplasm subtype and population. In the elderly (75 years or older), rates of diffuse large B-cell lymphoma (DLBCL) and follicular lymphoma increased 1.4% and 1.8% per year, respectively, whereas rates of chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL) declined 2.1% per year. Although whites bear the highest incidence burden for most lymphoid neoplasm subtypes, most notably for hairy cell leukemia and follicular lymphoma, black predominance was observed for plasma cell and T-cell neoplasms. Asians have considerably lower rates than whites and blacks for CLL/SLL and Hodgkin lymphoma. We conclude that the striking differences in incidence patterns by histologic subtype strongly suggest that there is etiologic heterogeneity among lymphoid neoplasms and support the pursuit of epidemiologic analysis by subtype.

Familial aggregation and heterogeneity of non-Hodgkin lymphoma in population-based samples

The importance of genetic factors in the etiology of non-Hodgkin lymphoma (NHL) is suggested by case-control and cohort studies. Most previous studies have been too small to estimate accurately risks of specific categories of lymphoproliferative malignancies in relatives of NHL cases or to quantify the contribution of NHL case characteristics to familial risk. We have overcome sample size limitations and potential recall bias by using large databases from Sweden and Denmark. Diagnoses of lymphoproliferative malignancies were compared in 70,006 first-degree relatives of 26,089 NHL cases (including 7,432 with subtype information) versus 161,352 first-degree relatives of 58,960 matched controls. Relatives of NHL cases were at significantly increased risk for NHL [relative risk (RR), 1.73; 95% confidence interval (95% CI), 1.39-2.15], Hodgkin lymphoma (RR, 1.41; 95% CI, 1.0-1.97), and nonsignificantly for chronic lymphocytic leukemia (CLL; RR, 1.31; 95% CI, 0.93-1.85). No increased risk was found for multiple myeloma among case relatives. Findings with respect to siblings compared with parents and offspring or with respect to age at diagnosis of proband were inconsistent. In both populations, relatives of cases with an aggressive NHL subtype were at substantially increased risk of NHL (combined RR, 3.56; 95% CI, 1.80-7.02). We conclude that NHL has an important familial component, which is shared with Hodgkin lymphoma and CLL. We estimate that the absolute lifetime risk for a first-degree relative of an NHL case to develop NHL is 3.6% (compared with a population risk of 2.1%) and higher if the index case had an aggressive subtype of NHL.

No evidence for anticipation in lymphoproliferative tumors in population-based samples

Genetic anticipation in familial non-Hodgkin's lymphoma, Hodgkin's lymphoma, and chronic lymphocytic leukemia (CLL) has been consistently reported in the literature. However, most of these findings were based on data from families ascertained for genetic studies. Fecundity bias, right censoring bias, and secular trends can lead to erroneous conclusions regarding the presence of anticipation. Our report investigates anticipation in four lymphoproliferative cancers, non-Hodgkin's lymphoma, Hodgkin's lymphoma, CLL, and multiple myeloma, drawn from Swedish and Danish population-based registries. We used marginal survival methods to test for a relative difference in age at diagnosis between parents and offspring and to account for other risk factors, staggered entries, censored data, and correlations among relatives. Changes in incidence rates of lymphoproliferative tumors were accommodated in the models by using time-varying covariates for different periods of diagnosis. Whereas no anticipation was observed for Hodgkin's lymphoma, CLL, and multiple myeloma, our initial model, which controlled for gender and country, suggested a significant difference (hazard ratio, 0.5; 95% confidence interval, 0.33-0.75) in age at diagnosis between the parents and offspring in the non-Hodgkin's lymphoma sample. However, once we accounted for the significant change in non-Hodgkin's lymphoma incidence over time, the statistical difference between parents and offspring disappeared (hazard ratio, 0.99; 95% confidence interval, 0.56-1.76). Our results emphasize the importance of considering secular trends when evaluating the possibility of anticipation in lymphoproliferative cancers. This is the first study to consider the changes of incidence over time as a source of bias when evaluating anticipation in lymphoproliferative cancers.

Neighborhood Socioeconomic Status and Hodgkin's Lymphoma Incidence in California

Hodgkin's lymphoma occurrence has long been noted to associate with higher socioeconomic status (SES). However, the Hodgkin's lymphoma-SES association has not been examined recently or across important, possibly etiologically distinct, patient subgroups. In approximately 150 million person-years of observation in the multiethnic population of California, we examined the association of Hodgkin's lymphoma incidence with a composite measure of neighborhood-level SES in patient subgroups defined by age, sex, race/ethnicity, and Hodgkin's lymphoma histologic subtype. Using population-based cancer registry data on 3,794 Hodgkin's lymphoma patients diagnosed 1988 to 1992 and 1990 census data, we assigned a previously validated, multidimensional SES index to census block groups of patient residence. We then calculated neighborhood SES-specific incidence rates and estimated rate ratios using Poisson regression. Positive neighborhood SES gradients in Hodgkin's lymphoma incidence were observed only in young adults (ages 15-44 years at diagnosis) with nodular sclerosis Hodgkin's lymphoma and older adult (ages > or =45 years) White and Hispanic males with mixed cellularity Hodgkin's lymphoma. For young adults, associations were marked in Hispanic and Asian women, weaker in Hispanic and White men and White women, and subtle to nonexistent in Blacks and Asian men. Neighborhood SES gradients in Hodgkin's lymphoma incidence varied by age, sex, race/ethnicity, and histologic subtype, underscoring etiologic complexity in Hodgkin's lymphoma. Racial/ethnic gradients were not entirely explained by neighborhood SES. In California, etiologically relevant exposures for young adult Hodgkin's lymphoma, the most common form, could associate more with race/ethnicity or foreign birthplace than neighborhood SES and may be modified by reproductive or other sex-specific factors.

Familial clustering of Hodgkin lymphoma and multiple sclerosis

BACKGROUND

Epidemiologic similarities between Hodgkin lymphoma in young adults (i.e., between 15 and 44 years old) and multiple sclerosis have led to the suggestion that these diseases may have related etiologies. Previous investigations have not supported this hypothesis, but the negative results could have been caused by methodologic problems. We therefore assessed the risk of developing Hodgkin lymphoma for patients with multiple sclerosis and for their families and the risk of developing multiple sclerosis for patients with Hodgkin lymphoma and for their families.

METHODS

We identified 11,790 patients with multiple sclerosis and 19,599 of their first-degree relatives in Danish population-based registers and followed them for the occurrence of Hodgkin lymphoma. Analogously, we identified 4381 patients with Hodgkin lymphoma and 7388 of their first-degree relatives and followed them for the occurrence of multiple sclerosis. The relative risks (RRs) of Hodgkin lymphoma and multiple sclerosis were expressed as standardized incidence ratios (i.e., the ratio between observed and expected numbers of outcomes based on age, sex, and period-specific incidence rates). All statistical tests were two-sided.

RESULTS

Overall, six cases of Hodgkin lymphoma were identified in patients with multiple sclerosis (RR for Hodgkin lymphoma = 1.40, 95% confidence interval [CI] = 0.63 to 3.12), two of which occurred in young adults (RR = 1.59, 95% CI = 0.40 to 6.37). The risk of young-adult-onset Hodgkin lymphoma was statistically significantly increased in the first-degree relatives of patients with multiple sclerosis (RR = 1.93, 95% CI = 1.01 to 3.71; n = 9 such lymphomas). Two cases of multiple sclerosis were identified among young adult patients with Hodgkin lymphoma (RR for multiple sclerosis = 0.82, 95% CI = 0.20 to 3.27), and the risk for multiple sclerosis was statistically significantly increased in their first-degree relatives (RR = 2.76, 95% CI = 1.44 to 5.31; n = 9 such multiple sclerosis cases).

CONCLUSION

The observed familial clustering of multiple sclerosis and young-adult-onset Hodgkin lymphoma is consistent with the hypothesis that the two conditions share environmental and/or constitutional etiologies.

Familial aggregation of Hodgkin lymphoma and related tumors

BACKGROUND

The importance of genetic factors in the etiology of Hodgkin lymphoma (HL) has been suggested by family and population studies. However, the spectrum of malignancies associated with common genetic etiology and the effects of gender and age on familial risk have not been established.

METHODS

Diagnoses of lymphoproliferative malignancies were compared in 15,799 first-degree relatives of 5047 patients with HL versus 32,117 first-degree relatives of 10,078 control probands from Sweden and in 7185 first-degree relatives of 2429 patients with HL versus 27,434 first-degree relatives of 8,495 control probands from Denmark using marginal survival models.

RESULTS

The risk of HL in relatives of patients with HL was increased significantly in both populations, with relative risks of 3.47 (95% confidence interval [95% CI], 1.77-6.80) in Sweden and 2.55 (95% CI, 1.01-6.45) in Denmark and a pooled estimate of 3.11 (95%CI, 1.82-5.29). In Sweden, risks for relatives of patients also were increased significantly for chronic lymphocytic leukemia and non-Hodgkin lymphoma (in males). Relative risks were higher in males compared with females and in siblings of patients compared with parents and offspring of patients. Relatives of patients with earlier-onset disease were at higher risk for HL.

CONCLUSIONS

HL has an important familial component, which is stronger in families of affected individuals age < 40 years, in males, and in siblings, and it is shared with some (but not other) lymphoproliferative malignancies. The cumulative lifetime risks are very small, however, for the development of HL de novo or in first-degree relatives of affected patients.

Hodgkin’s lymphoma in Chinese migrants to British Columbia:a 25-year survey

BACKGROUND

Compared with the West, Hodgkin's lymphoma in Oriental countries is characterized by a lower incidence rate and a higher proportion of mixed cellularity histology. Both environmental and genetic factors may be involved.

PATIENTS AND METHODS

The incidence and pattern of pathology of Hodgkin's lymphoma in the migrant Chinese population (0.4 million) in British Columbia (population 3.2 million) were studied. From a computerized database, all Hodgkin's lymphoma cases diagnosed in British Columbia from 1970 to 1997 were identified. Chinese descent was determined using patient surname by standard methodology and verified from the treatment record or by patient interview. The corresponding figures from the Chinese population in Hong Kong were used for comparison. For incidence rates, the age-specific incidence of Hodgkin's lymphoma in Hong Kong was obtained from the government cancer registry. For comparison of histology subtypes, 200 Hodgkin's lymphoma records from a Hong Kong regional referral center for the same time period were reviewed. Crude and age-standardized incidence rates were calculated by 5-year intervals in terms of age and calendar year, and relative rates were compared between the three populations.

RESULTS

From 1970 to 1997, Hodgkin's lymphoma was diagnosed in 34 Chinese patients in BC, with 24 cases diagnosed from 1970 to 1994. Thus, the crude and age-adjusted incidence rates from 1970 to 1994 were 0.91 and 1.14 per 100,000 per year in the British Columbia Chinese migrant population. Within the same period, 1862 cases of Hodgkin's lymphoma were diagnosed in British Columbia, giving a provincial background crude and age-adjusted incidence rates of 5.2 and 4.87 per 100,000 per year. The number of cases in the Hong Kong Chinese population (1970-1994) was 404, giving crude and age-adjusted incidence rates of 0.32 and 0.31 per 100,000 per year, respectively. Corrected for age and calendar year trends, the observed 25-year incidence of Hodgkin's lymphoma in British Columbia Chinese was significantly lower than expected from the British Columbia background population [24 observed versus 71 expected cases; standardized incidence ratio (SIR) = 0.34; 90% confidence interval (CI) 0.24-0.48; P <0.0001]. On the other hand, it is higher than that expected by extrapolating from the Hong Kong Chinese population (24 observed versus 8.5 expected cases; SIR = 2.81; 90% CI 1.94-3.95; P <0.0001). The difference is mainly accounted for by young patients with nodular sclerosis type disease in the migrant population.

CONCLUSIONS

Although any conclusion about the impact of migration on Hodgkin's lymphoma incidence and types in the Chinese population must be considered tentative due to the small number of observed cases and confounding variables such as age, changing diagnostic standards and secular trends in Hodgkin's lymphoma rates, our data demonstrate a tendency for the Chinese population of British Columbia to take on a Western pattern of Hodgkin's lymphoma. This observation provides additional evidence that both genetic and environmental influences play a role in the pathogenesis of this lymphoma, and that environmental factors can exert their influence over a relatively short period of time.

The Scotland and Newcastle epidemiological study of Hodgkin's disease: impact of histopathological review and EBV status on incidence estimates

AIMS

The epidemiological and pathological features of Hodgkin lymphoma (HL) are complex. The Epstein-Barr virus (EBV) is consistently associated with a proportion of cases, and these cases are thought to represent a distinct aetiological subgroup of HL. The aim of the present analysis was to determine the age and sex specific incidence of EBV associated and non-associated HL, analysed separately, using data derived from a population based study-the Scotland and Newcastle epidemiological study of Hodgkin's disease (SNEHD). This study also provided a unique opportunity to evaluate accuracy in the current diagnosis and classification of HL.

METHODS

SNEHD analysed consecutive cases of HL diagnosed in the study area between 1993 and 1997. Diagnostic biopsy material was retrieved, EBV status of tumours was determined, and histological review was performed.

RESULTS

In total, 622 cases were eligible for the study, and EBV studies and histopathological review were performed on biopsy material from 537 and 549 cases, respectively. Accuracy in the overall diagnosis of HL and classification of nodular sclerosis HL was good, but diagnosis of HL in the elderly and classification of other subtypes was less reliable. One third of classic HL cases were EBV associated, and age specific incidence curves for EBV associated and non-associated cases were distinct.

CONCLUSIONS

Comparison of age specific incidence curves for EBV associated and non-associated HL supports the hypothesis that these are two distinct aetiological entities. Accuracy in the diagnosis of HL is generally good, but certain subgroups of cases continue to present diagnostic difficulties.

Epidemiology of Hodgkin's disease and non-Hodgkin's lymphoma

This review considers in detail the descriptive and aetiological epidemiology of Hodgkin's disease and non-Hodgkin's lymphoma (NHL), with attention to histological subcategories when the literature allows. The aetiology of Hodgkin's disease remains only partially understood. There is evidence that Epstein-Barr virus (EBV) may be involved in the causation of some cases, and clinical immune deficiency is a risk factor for a few, but the evidence is not entirely consistent and other factors may also be important in causing the EBV-associated cases of Hodgkin's disease. The cause of EBV-unassociated cases remains obscure. For NHL, although it has been shown that some cases are related to immune deficiency and chronic antigenic stimulation, and especially to EBV in the context of immune deficiency, the causation of the majority of cases remains unknown. The increasing incidence of NHL, other than that related to AIDS, is also essentially unexplained. Epidemiological investigation of the aetiology of NHL and Hodgkin's disease is making steady progress, however, and there remain leads to be followed that may result in a better understanding and hence prevention.

Hodgkin's disease in Asians: incidence patterns and risk factors in population-based data

Hodgkin's disease (HD) has been reported to be rare in Asians. Data sparseness has hindered studies exploring the relative contributions of environment and heredity to HD etiology, and individual risk factors have never been studied in an Asian population. With the most recent, uniformly collected population-based data from the US and Asia, we compared HD incidence rates in Chinese, Japanese, Filipinos, and Asian Indians in the US and in Asia. HD incidence rates were quite low in all Asian subgroups, but approximately double in US Asians as in native Asians. In both, rates were lower for Japanese and Chinese than for Filipinos and Asian Indians. A modest young-adult rate peak occurred for most US Asian groups, but not for any population in Asia. In data from a population-based case-control study of HD in San Francisco area women, young-adult Asian cases, like young-adult cases of other racial/ethnic groups, had childhood social environments indicative of less early contact with children. Given environmental and lifestyle differences between the US and Asia, the consistently low rates of HD in Asians suggest genetic resistance to disease development, possibly associated with HLA type. International and inter-ethnic differences, and risk factor patterns in case-control data, implicate environmental influences in the etiology of HD.

Age variation in Hodgkin's disease risk factors in older women: evidence from a population-based case-control study

Hodgkin's disease (HD), which affects all age groups, has been associated with childhood social class, particularly among adults under age 40. Little is known about social class risk factors in older adults, and the few existing studies have conflicting findings. As part of a population-based case-control study of HD in women, we examined social class risk factors by diagnostic age groups (45-54 years and 55-79 years) corresponding to incidence patterns and by histologic subtypes based on a uniform pathologic review. Among women ages 45-54, cases were more likely to be Catholic, to have lower income and to be taller than controls. Among women ages 55-79, cases tended to have come from small or large childhood households, lived in single-family childhood housing, and had a single rather than shared bedroom at age 11. For the nodular sclerosis (NS) histologic subtype, similar age differences in risk factors were apparent. Comparisons between the NS and non-NS subtypes in women ages 55-79 identified some common risk factors (single-family childhood home, single bedroom at age 11) but others specific to one subtype (childhood household size, adult height for NS; lower maternal education for non-NS). Thus, some social class associations with HD differed between middle-aged and older women, as well as between these groups and younger adults, while others were shared across age groups. Risk also was associated with both higher and lower childhood social class in middle-aged and older women, in contrast with previous findings. None of these patterns was explained entirely by histologic subtype but may reflect age and histology subtype variation in the HD-EBV association.

Incidence of Hodgkin's disease in Nordic countries

We analysed age and sex-specific trends in the incidence of Hodgkin's lymphoma in Denmark, Sweden, Norway, and Finland during 1978-97. The incidence of Hodgkin's lymphoma decreased significantly in all age groups above 40 years; there was a significant increase in incidence among adolescents and young adults. This increase occurred primarily for Hodgkin's lymphoma of the nodular sclerosis subtype. These observations emphasise the need to identify risk factors for Hodgkin's lymphoma in the young.

Expert review of the diagnosis and histologic classification of Hodgkin disease in a population-based cancer registry: interobserver reliability and impact on incidence and survival rates

BACKGROUND

The reliability of Hodgkin disease (HD) diagnosis and histologic classification is an ongoing concern but has not been evaluated in a population-based case series in 20 years. Yet, diagnostic error in cancer registry data used in surveying HD occurrence may produce statistics that misrepresent incidence, mortality, or survival.

METHODS

Uniform pathology review was attempted for all 395 women ages 19--79 years with incident HD reported to a population-based cancer registry in 1988--94. Agreement between original registry and review diagnoses was measured with positive predictive values and kappa statistics. Incidence rates and survival probabilities were computed based on registry and review diagnoses.

RESULTS

Registry and review diagnosis agreed for 245 of the 362 reviewed cases. Positive predictive values varied by histologic subtype (nodular sclerosis, 95%; lymphocyte predominance, 69%; mixed cellularity, 58%; lymphocyte depletion, 0%; not otherwise specified, 40%), but agreement was good overall (kappa, 0.66, 95% confidence interval, 0.56--0.76). Eleven patients were determined not to have HD; all were older than age 44 years. Hodgkin disease incidence rates differed for original and review diagnoses only in older women, for whom registry rates slightly overestimated incidence. Five-year survival rates did not differ for registry and review data overall or by age group.

CONCLUSIONS

For most adult women patients, the diagnosis of HD was confirmed on review, reflecting the very good agreement between registry and review diagnoses for nodular sclerosis, the most common subtype. Thus, cancer registry statistics for this time period can provide accurate estimates of disease patterns for HD overall and for the nodular sclerosis variant. For other histologic subtypes, rates may be unreliable, and HD occurrence overall may be less dependable in populations with larger proportions of these subtypes.

Epidemiology of lymphomas

Non-Hodgkin lymphoma (NHL) is the fifth most common cancer in the US, with about 55,000 new cases estimated for the year 2000. According to the new Surveillance, Epidemiology, and End Results (SEER) data from 1973 to 1997, the age-adjusted incidence rates rose by about 80%, with an annual percentage increase of nearly 3%, which is faster than for the majority of cancers. The increasing incidence of NHL is largely unexplained. AIDS-related NHL accounts for some but not all of the increase. The American Cancer Society predicts about 7,400 new cases of Hodgkin Disease (HD) in the year 2000 in the US. The incidence of HD is consistently lower than that of NHL, and has decreased about 16% since the 1970s. Only a small portion of the decrease in HD incidence can be explained by misdiagnosis of HD as NHL. Further research is needed on the cofactors that predispose AIDS cases to lymphoma, as well as other possible causes of NHL such as immunosuppression, genetics, viruses, medical conditions, pesticides, solvents, hair dyes, and diet. Further evaluation of the role of viruses, occupational exposures, and genetics in the etiology of HD should prove valuable.

Time trends and sex patterns in Hodgkin's disease incidence in Canada, 1970-1995

PURPOSE

To examine time trends and sex patterns in Hodgkin's disease incidence in Canada, from 1970 through 1995.

METHOD

In addition to analyses of the secular trends and sex ratio in incidence rates, age-period-cohort models were fitted to estimate the effects on the trends. Age-specific male/female incidence rate ratios were examined for the disease and for its two major histologic subtypes.

RESULTS

The overall age-adjusted incidence rate of Hodgkin's disease decreased significantly in males (3.5 per 100,000 in 1970-71 to 2.8 in 1994-95) but only slightly in females (2.4 per 100,000 to 2.3). There was a significant increase in the incidence among females aged 10-29 and among males aged 10-24, but a dramatic decrease among older ages. Age-period-cohort modelling showed that birth cohort and period effects were responsible for the observed trends in males and females, respectively.

CONCLUSION

The risk factors responsible for Hodgkin's disease are different in females and males. Reproductive factors are likely to be associated with the occurrence of the disease in young women.

The rise in incidence of lymphomas in Europe 1985-1992

A collaborative study was carried out of the descriptive epidemiology of the lymphomas from seven countries across Europe in the period 1985-1992. Careful attention was paid to sources of information and the data quality in close collaboration with expert histopathologists. The data were classified as non-Hodgkin's lymphoma (NHL) and Hodgkin's disease (HD). An attempt was made to put the data into a modified version of the Revised European American Lymphoma (REAL) classification. We observed an overall rise in total NHL throughout the time period in all European countries but no such trend in HD. The increase in NHL overall being 4.2% per annum, representing an increase of 4.8% in males and 3.4% in females per annum, was only marked in middle and old age. Such increases were observed in all participating areas except in Burgundy. Different countries, however, have different base rates, the rates being highest in Scandinavia and the Netherlands. The analysis by subcategory classification suggested that the increase in NHL was confined to the follicle centre cell type, extranodal B-cell, nodal T-cell and nodal lymphomas not otherwise specified, categories. These new observations present a picture of real increase in case incidence with no obvious explanation. The increases in NHL do not appear to be due solely to better diagnoses. Pending other explanations or refutation, these present a compelling picture of an inexorable rise in incidence of this disease.

The many faces of Hodgkin's disease around the world: what have we learned from its pathology?

In the past decade there have been many advances in our understanding of Hodgkin's disease. Among the most important is the discovery that the Reed-Sternberg cell is a lymphoid cell, in most cases a B cell, and that it is clonal, and thus a true lymphoma, deserving of a name change, to 'Hodgkin's lymphoma' (HL). Based on a combination of immunophenotype and morphology, the R.E.A.L. Classification recognizes two main types of HL: classical types (nodular sclerosis, mixed cellularity, lymphocyte-rich classical HL, and lymphocyte depletion) and nodular lymphocyte predominance type (NLPHL), which probably represent distinct biological entities. The immunophenotype and genetic features of both classical HL and NLPHL have been defined. These are useful in the subclassification of HL and in distinguishing HL from two recently-described, aggressive lymphomas that were in the past often diagnosed as HL: anaplastic large-cell lymphoma, T-cell type (ALCL), and T-cell/histiocyte-rich large B-cell lymphoma (T/HRBCL). Epstein-Barr virus has been detected in approximately 40% of the cases of classical HL, and is clonal, suggesting that this virus may play a role in the pathogenesis of at least some types of HL. The frequency of HL varies in different populations, and the frequency of EBV-positive HL appears to be inversely related to the overall frequency of HL in a given population. Thus, it is possible that its presence may simply reflect the prevalence of EBV-infected B cells in the individual. Despite the advances of the past ten years, many questions remain to be answered, and these will provide the challenges of the next decade.

Epstein-Barr virus in the pathogenesis of Hodgkin's disease

Epidemiologic and clinico-pathologic features of Hodgkin's disease suggest that an infectious agent may be involved in the pathogenesis of this puzzling disorder. Recently accumulated data provide direct evidence supporting a causal role of Epstein-Barr virus in a significant proportion of cases. In addition to allowing a better understanding of the complex pathogenesis of Hodgkin's disease, these virological advances, briefly reviewed herein, also constitute an important basis for the development of new therapeutic strategies.

Incidence and time trends in Hodgkin's disease: from parts of the United Kingdom (1984-1993)

Over 3,000 cases of Hodgkin's Disease diagnosed between 1984-93 were used to examine incidence and time trends. These data are part of the Leukaemia Research Fund's specialist Data Collection Study, which is the only large, population-based data set of its type in Europe. The age specific incidence curves showed different patterns for nodular sclerosis contrasted with all other subtypes combined (non-nodular sclerosis). For nodular sclerosis, there was a female excess for young adults, while for non-nodular sclerosis a gradual rise in incidence with age in both sexes was observed. Incidence varied over time, showing a complex pattern with a decreasing trend in males in all Rye-subtypes and no significant change among females diagnosed with nodular sclerosis. These complex patterns of change are different from those seen in other countries. It is concluded that the results provide clear evidence of the heterogeneity of Hodgkin's disease between the sexes and between subtypes, which should be taken into account in future studies.

Hodgkin's disease in the setting of human immunodeficiency virus infection

Although Hodgkin's disease (HD) is not usually associated with congenital or acquired immunodeficiency disorders, recent evidence would suggest a statistically significant increase in HD among individuals infected with human immunodeficiency virus (HIV). In the setting of underlying HIV infection, clinical and pathologic characteristics of HD may differ from usual expectations. Thus, 70%-100% of HIV-infected patients with HD present with systemic "B" symptoms. Likewise, disseminated, stage III or IV disease is reported in approximately 75%-90%. Bone marrow is a common site of extranodal HD, occurring in 40%-50%. Complete response rates after multiagent chemotherapy range from approximately 45% to 70%, although median survival has been only in the range of approximately 18 months. Hematologic toxicity from multiagent chemotherapy may be substantial, even with the use of hematopoietic growth factor support. It is apparent that new strategies of therapeutic intervention must be explored.

What causes Hodgkin's disease in children?

Hodgkin's disease is one of the commonest cancers of older children and adolescents, but little is known about its aetiology. Recent data, particularly in descriptive epidemiology and virology, tend to confirm the 'two-disease' hypothesis. Mixed cellularity Hodgkin's disease is more common, especially at younger ages, in poorer socioeconomic environments, whereas nodular sclerosing Hodgkin's disease has a higher incidence in more affluent societies. Approximately three-quarters of childhood Hodgkin's disease, and a higher proportion of the mixed cellularity subtype, may be a rare response to Epstein-Barr virus infection, together with an unidentified cofactor related to the degree of affluence of the population. Other infectious agents may be implicated in some cases. The already low incidence, especially of nodular sclerosis, among populations of East Asian ethnic origin and the high incidence, especially of mixed cellularity, among some populations of South Asian origin are apparently independent of socioeconomic status. This ethnic variation in risk suggests that genetic predisposition also plays a role. Detailed HLA studies may help to elucidate the complex variations between populations in the risk of Hodgkin's disease and its principal subtypes.

Hodgkin's disease in a national and hospital population: trends over 20 years

The aim of the study was to investigate the incidence rate and time trends in a national registry population of Hodgkin's disease (HD) and the effects of selection in a hospital population. A national registry population of all HD patients from Norway and a hospital population of HD patients treated at the Norwegian Radium Hospital (NRH) were studied retrospectively from 1971 to 1993. The incidence of non-Hodgkin's lymphomas (NHL) in Norway increased steadily from 1961 in contrast to a stable incidence pattern for HD before 1980 and a decreasing incidence since 1980. Due to improved diagnostic tools after 1980, an increasing proportion of patients previously diagnosed as lymphocyte depleted and unclassified HD were classified as NHL. As these histologies are dominant in older patients, the incidence of older patients with HD and the total population of HD have decreased since 1980. As a result, the proportion of young adults with a favourable histology has increased. These changes may partly explain the increased patient survival observed both in the national and the hospital population. The hospital population comprised 92% of patients aged 15-39 years, 80% of patients aged 40-59 years and 53% of patients aged > 60 years in the national population. The selection of younger patients in the hospital material may explain a higher survival rate as compared with the national population.

Mistaken diagnoses of Hodgkin's disease

This article reviews the frequency of and general types of diagnostic errors in Hodgkin's disease (HD) over the past several decades, discusses the most common diagnostic errors in the four histologic subtypes of HD today, and describes some of the clinical and pathologic features that may aid in avoiding a mistaken diagnosis of HD.

HIV-associated Hodgkin's disease. Biologic and clinical aspects

The incidence of HD appears to have increased in HIV-infected individuals, with HIV-seropositive intravenous drug users most likely to develop the disorder. All groups at risk for HIV, however, may develop HD. The pathologic spectrum of HD in the setting of HIV infection is distinct from that seen in "de novo" HD in the United States, with the majority of patients diagnosed with the mixed cellularity subtype, as opposed to the more usual occurrence of nodular sclerosis in "de novo" disease. The presence of fibrohistiocytic stromal cells within involved tissues is also a distinct characteristic of HIV-associated HD. Epstein-Barr viral genome has been detected within tumor cell nuclei, and it may be involved in the pathogenesis of disease. Clinically, patients often present with systemic "B" symptoms and widely disseminated extranodal disease, seen in 75% to 90%. Bone marrow is involved in 40% to 50% of cases at diagnosis. Complete remission may be achieved in approximately 50% of patients after use of combination chemotherapy, but median survival is short, in the range of 12 to 18 months. Death is often due to bacterial or opportunistic infection (or both), often occurring in the setting of chemotherapy-induced neutropenia.

The epidemiology of AIDS--related neoplasms

The magnitude for and risk factors of the two most important AIDS neoplasm, Kaposi's sarcoma and non-Hodgkin's lymphoma, are reviewed in detail. The association between AIDS and other cancers is mostly speculative because surveillance biases tend to favor detecting associations that may be spurious. The overall relative risk of other cancers appears, however, to be only twofold above that in the general population, with associations being most convincing for anal (but not cervical) cancer and leiomyosarcoma and possible also for Hodgkin's disease, testicular cancer, and conjunctival cancers.

The incidence of non-Hodgkin's lymphoma and its histologic subtypes in Asian migrants to the United States and their descendants

We examined the incidence of non-Hodgkin's lymphoma (NHL) in Chinese, Japanese, and Filipino residents of the United States to obtain further clues about the etiology of the disease. The age, race, and birthplace of residents of Hawaii, San Francisco/Oakland (California), and western Washington who had received a diagnosis of NHL during the period 1973-86 were obtained from population-based cancer registries, and a special tabulation from the 1980 Census was used to estimate the number of person-years at risk for each category of resident. The incidence of NHL in each of the Asian groups examined was 35 to 85 percent that of US-born Whites. However, there was no consistent trend of increasing incidence with increasing generation of residence in any of the groups. In Asian-Americans, the risk of small cell lymphocytic and plasmacytoid lymphoma was 10 to 85 percent that of Whites, although no clear trends of risk with generation of residence in the US were observed. They also were at a reduced risk of follicular lymphoma, and in Chinese and Japanese persons, the risk was lower in first generation than in later generation migrants (Chinese: Asian-born relative risk [RR] = 0.11, US-born, RR = 0.84; Japanese: Asian-born, RR = 0.15, US-born, RR = 0.36). The risk of diffuse lymphoma was similar in Chinese- and Japanese-Americans and US-born Whites. We conclude that, with the exception of follicular lymphoma, the basis for the relatively low incidence of NHL in Asian-Americans does not lie in exposures or characteristics that differ between the migrants themselves and their descendants.

Hodgkin's disease

BACKGROUND

Over three time periods, 1973-1977, 1978-1982, and 1983-1987, the Surveillance, Epidemiology, and End Results (SEER) program of the National Cancer Institute collected all cases of Hodgkin's disease in designated geographic regions representative of the United States as a whole.

METHODS

The authors reviewed the data pertaining to 9418 microscopically confirmed cases of Hodgkin's disease and focused on trends that emerged over the time intervals of this study.

RESULTS

Hodgkin's disease had a bimodal distribution of age-specific incidence rates with two peaks in the age groups of 15-34 years and older than 55 years. Since 1973, the incidence of Hodgkin's disease in the younger age group increased progressively as a result of a marked increase in the incidence of the nodular sclerosis subtype. From the period 1973-1977 to 1983-1987, the age-adjusted incidence rate of nodular sclerosis rose from 1.1 to 1.6 per 100,000. In 1983-1987, nodular sclerosis represented 57.7% of Hodgkin's disease and occurred most often in whites, with an equal sex ratio. In females, this increase in incidence over time was most dramatic in young adult women. The overall incidence of the mixed cellularity subtype, 23.4% of Hodgkin's disease, remained stable although the age-specific incidence rate increased progressively in black males older than age 40 years. The incidence of the lymphocytic predominance subtype, 6.0% of Hodgkin's disease, remained stable over time, with a slight increase in adults older than age 50 years. The lymphocytic depletion subtype, 3.8% of Hodgkin's disease, occurred predominantly in the elderly; its incidence decreased, most likely the result of changes in diagnostic criteria, with many cases being reclassified as non-Hodgkin's lymphoma (NHL). Similarly, unclassifiable cases of Hodgkin's disease designated as miscellaneous, 9.1% of Hodgkin's disease, decreased over time, probably the result of improved classification. Nevertheless, a subset of cases of Hodgkin's disease remained difficult to subclassify. The human immunodeficiency virus (HIV) epidemic appears to be associated with an increased incidence of Hodgkin's disease in San Francisco County in adult males age 30-49 years, a population known to have a high prevalence of HIV infection.

CONCLUSION

The SEER data suggest that Hodgkin's disease is a heterogeneous entity composed of at least two different diseases--nodular sclerosis and mixed cellularity. Over the time course of this study, the incidence of nodular sclerosis increased dramatically, particularly in adolescents and young adults, whereas mixed cellularity remained stable. The incidence of Hodgkin's disease in the elderly decreased, most likely the result of our improved ability to diagnose both Hodgkin's disease and NHL and the realization that many cases of NHL had been misclassified as Hodgkin's disease. This decrease in Hodgkin's disease occurred predominantly in the lymphocytic depletion and miscellaneous groups.

Cancer incidence trends in women at high risk of human immunodeficiency virus (HIV) infection

To determine the types and rates of tumors which may be associated with HIV infection in women, we used cancer incidence data from New York and northern New Jersey. We examined changes in incidence of selected cancers in women aged 20-49 years and compared groups differing in incidence of AIDS. Black women were compared to white women in New York City and in the remainder of New York State; for cervical cancer, rates were also compared for Blacks and Whites in northern New Jersey. The incidence of Kaposi's sarcoma in women increased in New York City, beginning in 1982 for Blacks and in 1984 for Whites, but remained stable in the remainder of New York State. The incidence of non-Hodgkin's lymphoma in New York women doubled in Blacks after 1982 whereas incidence trends in Whites were unchanged. No consistent variation was seen in the incidence of Hodgkin's disease. Cervical cancer in New York and northern New Jersey Blacks declined over the same period by approximately 40% for invasive tumors and 50% for in situ lesions. The HIV epidemic is associated with substantial excesses of Kaposi's sarcoma and non-Hodgkin's lymphoma in women. The absence of Kaposi's sarcoma in upstate New York women suggests the existence of a geographically restricted co-factor(s) for Kaposi's sarcoma in addition to HIV. If HIV affected cervical cancer incidence through 1988, its impact was small compared to the striking decreases which followed widespread adoption of Papanicolaou screening.

Viral involvement in Hodgkin's disease

The etiology of Hodgkin's disease (HD) is unknown, but a growing body of evidence suggests that the Epstein-Barr virus (EBV) plays a role in a proportion of cases. Clonal EBV genomes have been detected in affected tissues, and EBV has been localized to Reed-Sternberg (RS) cells, the putative malignant cells in HD. EBV latent genes, including the EBER RNAs and the latent membrane protein, LMP-1, are expressed by RS cells. These data suggest that EBV is playing a role in the pathogenesis of HD; however, it is clearly not involved in all cases. Using in situ hybridization, we can detect EBV within the RS cells in approximately 40% of cases. Epidemiological data suggest that HD is a heterogeneous condition and the distribution of EBV-associated cases is not random. Studies from several groups indicate that mixed cellularity cases are more likely to be EBV-associated than nodular sclerosis cases. Our data further suggest that the majority of pediatric and older cases of HD are EBV-associated, whereas the RS cells in young adult cases only rarely harbor EBV. We therefore speculate that another virus is responsible for the young adult peak in incidence which is seen in developed countries.