Trends in mortality from Hodgkin's disease in western and eastern Europe

Cancer Mortality in Italy, 1970–2002

Aims and background

To update previous work on Italian cancer mortality.

Methods

WHO data were used to calculate death rates for 30 cancer sites for 2002. Trends were analyzed with joinpoint regression over the 1970–2002 period.

Results

Total cancer deaths for 2002 in Italy were 163,070 (93,398 men, 69,672 women). Male cancer mortality rose until 1988 and since then has had a 1.4% yearly fall. The first cause of cancer death in males was lung cancer, accounting for 28% of deaths. The decrease in mortality from male lung cancer came about the end of the 1980's (estimated annual percentage change, EAPC, −1.26 from 1989 to 1993 and −2.32 thereafter) and was the main reason for the favorable trends in total male cancer mortality, reflecting the change in smoking prevalence in Italian males. Female total cancer mortality trends have also been favorable, with an overall yearly drop of 1.1% since 1992. The most frequent causes of cancer deaths in females were breast and colorectal cancers, accounting for 16% and 14% of cancer deaths, and both showed declining trends (EAPC, −1.80 since 1992 and −1.51 from 1993 for breast and colorectal cancers, respectively). Female lung cancer has been on the rise (EAPC, 0.82 since 1987) for the last decades due to the rise in cigarette smoking since the 1970's in Italian females.

Discussion

Mortality from the most common cancers in Italy showed a favorable trend over recent years, the maintenance and potential improvement of which would require a strategy focusing on the control of tobacco and alcohol consumption, nutrition and diet. Early diagnosis for selected neoplasms can also have a relevant impact, together with advancements in treatments.

Cancer Mortality in Italy, 2008, and Predictions for 2012

Aims and background

This report provides up-to-date data and statistics for cancer mortality in Italy in 2008, and predicts the figures and rates for selected cancer sites for 2012.

Methods

Cancer death certifications (for 30 sites) and resident population estimates in 2008 stratified by sex and age were obtained from the World Health Organization (WHO) database (WHOSIS). Mortality rates were age-standardized on the world standard population.

Results

Cancer deaths registered in Italy in 2008 were 172,783 (97,773 men and 75,010 women), corresponding to age-standardized death rates of 144.1/100,000 men and 84.3/100,000 women. The projected cancer deaths in 2012 are 178,000 (100,000 men, 78,000 women) and the corresponding rates 132,5/100,000 men and 80.5/100,000 women. The favorable trend in lung cancer mortality among men was confirmed, with rates of 37.7/100,000 in 2008 (all ages) and 33.3 for 2012. Other tobacco-related cancers also declined in men but not in women, including pancreatic cancer, whose rates tended to level off over the last 3 years. The fall in female cancer mortality rates continues to be led by favorable trends in breast cancer (16.1/100,000 in 2007 and 15.2 in 2012), intestinal cancer, stomach cancer and uterine cancer. However, the female lung cancer mortality was still rising with 7743 deaths in 2008 (9.5/100,000), and lung cancer is predicted to become the second cause of female cancer mortality by 2012 (8,500 deaths, 9.8/100,000).

Conclusions

Reduced tobacco and alcohol consumption are largely responsible for the favorable trends in cancer mortality in men. Advances in treatment and management accounted for the reduced mortality from colorectal cancer, breast cancer, leukemias and a few other cancers, as well as improved diagnosis for colorectal, cervical and breast cancer. The rising epidemic of tobacco-related deaths in women indicates the need for targeted tobacco-control strategies.

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.

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.

Malignant lymphatic and hematopoietic neoplasms mortality in Serbia, 1991-2010: a joinpoint regression analysis

BACKGROUND

Limited data on mortality from malignant lymphatic and hematopoietic neoplasms have been published for Serbia.

METHODS

The study covered population of Serbia during the 1991-2010 period. Mortality trends were assessed using the joinpoint regression analysis.

RESULTS

Trend for overall death rates from malignant lymphoid and haematopoietic neoplasms significantly decreased: by -2.16% per year from 1991 through 1998, and then significantly increased by +2.20% per year for the 1998-2010 period. The growth during the entire period was on average +0.8% per year (95% CI 0.3 to 1.3). Mortality was higher among males than among females in all age groups. According to the comparability test, mortality trends from malignant lymphoid and haematopoietic neoplasms in men and women were parallel (final selected model failed to reject parallelism, P = 0.232). Among younger Serbian population (0-44 years old) in both sexes: trends significantly declined in males for the entire period, while in females 15-44 years of age mortality rates significantly declined only from 2003 onwards. Mortality trend significantly increased in elderly in both genders (by +1.7% in males and +1.5% in females in the 60-69 age group, and +3.8% in males and +3.6% in females in the 70+ age group). According to the comparability test, mortality trend for Hodgkin's lymphoma differed significantly from mortality trends for all other types of malignant lymphoid and haematopoietic neoplasms (P<0.05).

CONCLUSION

Unfavourable mortality trend in Serbia requires targeted intervention for risk factors control, early diagnosis and modern therapy.

The prevalence of opportunistic infections and malignancies in autopsied patients with human immunodeficiency virus infection in Japan

BACKGROUND

Opportunistic infections and malignancies such as malignant lymphoma and Kaposi sarcoma are significant complications of human immunodeficiency virus (HIV) infection. However, following the introduction of antiretroviral therapy in Japan in 1997, the incidence of clinical complications has decreased. In the present study, autopsy cases of HIV infection in Japan were retrospectively investigated to reveal the prevalence of opportunistic infections and malignancies.

METHODS

A total of 225 autopsy cases of HIV infection identified at 4 Japanese hospitals from 1985-2012 were retrospectively reviewed. Clinical data were collected from patient medical records.

RESULTS

Mean CD4 counts of patients were 77.0 cells/μL in patients who received any antiretroviral therapy during their lives (ART (+) patients) and 39.6 cells/μL in naïve patients (ART (-) patients). Cytomegalovirus infection (142 cases, 63.1%) and pneumocystis pneumonia (66 cases, 29.3%) were the most frequent opportunistic infections, and their prevalence was significantly lower in ART (+) patients than ART (-) patients. Non-Hodgkin lymphoma and Kaposi sarcoma were observed in 30.1% and 16.2% of ART (-) patients, and 37.9% and 15.2% of ART (+) patients, respectively. Malignant lymphoma was the most frequent cause of death, followed by cytomegalovirus infection regardless of ART. Non-acquired immunodeficiency syndrome (AIDS)-defining cancers such as liver and lung cancer caused death more frequently in ART (+) patients (9.1%) than in ART (-) patients (1.5%; P = 0.026).

CONCLUSIONS

The prevalence of infectious diseases and malignancies were revealed in autopsy cases of HIV infection in Japan. The prevalence of cytomegalovirus infection and pneumocystis pneumonia at autopsy were lower in ART (+) patients than ART (-) patients. Higher prevalence of non-AIDS defining malignancies among ART (+) patients than ART (-) patients suggests that onsets of various opportunistic infections and malignancies should be carefully monitored regardless of whether the patient is receiving ART.

Changes in period and cohort effects on haematological cancer mortality in Spain, 1952-2006

BACKGROUND

In contrast to other haematological cancers, mortality from non-Hodgkin's lymphoma and multiple myeloma increased dramatically during the second half of the 20th century in most developed countries. This widespread upward trend remains controversial, as it may be attributable either to progressive improvements in diagnosis and certification or to increasing exposures to little-known but relevant risk factors.

METHODS

To assess the relative contribution of these factors, we analysed the independent effects of age, death period, and birth cohort on haematological cancer mortality rates in Spain across the period 1952-2006. Weighted joinpoint regression analyses were performed to detect and estimate changes in period and cohort curvatures.

RESULTS

Although mortality rates were consistently higher among men, trends across periods and cohorts were virtually identical in both sexes. There was an early period trend reversal in the 1960s for Hodgkin's disease and leukaemia, which was delayed to the 1980s for multiple myeloma and the 1990s for non-Hodgkin's lymphoma. Birth cohort patterns showed a first downturn for generations born in the 1900s and 1910s for all haematological cancers, and a second trend reversal for more recent cohorts born in the 1950s and 1960s for non-Hodgkin's lymphoma and leukaemia.

CONCLUSIONS

The sustained decline in Hodgkin's disease mortality and the levelling off in leukaemia seem to be driven by an early period effect linked to improvements in disease treatment, whereas the steep upward trends in non-Hodgkin's lymphoma and multiple myeloma mortality in Spain are more likely explained by a cohort effect linked to better diagnosis and death certification in the elderly. The consistent male excess mortality across all calendar periods and age groups points to the importance of possible sex-related genetic markers of susceptibility in haematological cancers.

Long Term Outcome in Adolescents with Hodgkin's Lymphoma: Poor Results using Regimens Designed for Adults

It is unclear whether the outcome in adolescents with Hodgkin's lymphoma is as good as that in children and there are no prospective randomized trials comparing regimes used in children and adults in this setting. We have therefore performed an analysis of 210 adolescent patients diagnosed with Hodgkin's lymphoma between 1970-1997 and registered on the database held by the British National Lymphoma Investigation. Patients were treated according to adult regimens current at the time of their diagnosis. The complete response rate recorded in 209 patients was 76%. This was highly dependent on disease stage being 95% in patients with localized disease but 63% in those with advanced disease. The 5 year event free survival for the whole cohort was 50% falling to 41% at 20 years with overall survival of 81% falling to 68% at 5 and 20 years respectively. There is no significant difference in the 3 decades pertaining to this analysis. Of the 62 deaths in this cohort, 70% were due to Hodgkin's lymphoma but of the 13 deaths occurring beyond 10 years, only 3 were due to Hodgkin's lymphoma, the reminder being attributable to the late effects of therapy. Results from paediatric groups have been much more encouraging than those presented from this cohort. It seems the use of risk-adjusted combined modality therapy with minimization of radiation fields and doses and reduction of anthracycline and alkylator exposure has been successful in children and should be used in adolescents.

Cancer mortality in the European Union, 1970-2003, with a joinpoint analysis

BACKGROUND

Cancer mortality peaked in the European Union (EU) in the late 1980s and declined thereafter.

MATERIALS AND METHODS

We analyzed EU cancer mortality data provided by the World Health Organization in 1970-2003, using join point analysis.

RESULTS

Overall, cancer mortality levelled off in men since 1988 and declined in 1993-2003 (annual percent change, APC = -1.3%). In women, a steady decline has been observed since the early 1970s. The decline in male cancer mortality has been driven by lung cancer, which levelled off since the late 1980s and declined thereafter (APC = 2.7% in 1997-2003). Recent decreases were also observed for other tobacco-related cancers, as oral cavity/pharynx, esophagus, larynx and bladder, as well as for colorectal (APC = -0.9% in 1992-2003) and prostate cancers (APC = -1.0% in 1994-2003). In women, breast cancer mortality levelled off since the early 1990s and declined thereafter (APC = -1.0% in 1998-2003). Female mortality declined through the period 1970-2003 for colorectal and uterine cancer, while it increased over the last three decades for lung cancer (APC = 4.6% in 2001-2003). In both sexes, mortality declined in 1970-2003 for stomach cancer and for a few cancers amenable to treatment.

CONCLUSION

This update analysis of the mortality from cancer in the EU shows favorable patterns over recent years in both sexes.

Trends in cancer mortality in Switzerland, 1980-2001

Trends in cancer mortality in Switzerland were analysed over the period 1980-2001, on the basis of the World Health Organization database. Appropriately developed correction factors were utilized for the period before 1995, to allow for spurious trends introduced by the change between the 8th and the 10th revisions of the ICD. Steady declines in cancer mortality were observed, particularly from the mid-1980s onwards. Over the last decade, the fall in overall age-standardized (world standard) cancer mortality was 11.1% in men (from 158.1 in 1990-1991 to 140.6/100,000 in 2000-2001) and 7.6% in women (from 91.6 to 84.7/100,000), and the decline was larger in truncated rates from 35 to 64 years (-18.0 and -9.7%). In men, all major tobacco and alcohol neoplasms have declined until the late 1990s but have levelled off over the last few years, reflecting recent trends in alcohol and tobacco consumption. The fall in male lung cancer mortality was 20% over the last decade (from 42.9 to 34.3/100,000). In contrast, lung cancer mortality in women has steadily increased by 38% between 1981 and 1991 and by 47% between 1991 and 2001, to reach 10.7/100,000 at all ages and 18.3 at age 35 to 64, due to increased prevalence of smoking in subsequent generations of Swiss women. Other sites showing substantial declines include stomach and colorectum in both sexes, (cervix) uteri and breast in women. Likewise, prostate cancer showed modest favourable trends after 1995. Steady declines were observed for leukaemias, Hodgkin's disease and testicular cancer, namely, the neoplasms most influenced by therapeutic improvements, while trends in lymphomas and myeloma showed no clear pattern.

Pathology of pure hippocampal sclerosis in a patient with dementia and Hodgkin's disease: the Ophelia syndrome

An archive autopsy case of a 50-year-old man who died of Hodgkin's lymphoma had a 4-year, 4-month history of dementia. After radiochemotherapy, the lymphoma subsided except for involvement of the spleen, but the dementia remained. Neuropathological examination revealed that the pathology was confined to the hippocampus, both hippocampi showing sclerosis without inflammation. Neurons of sector cornu ammonis (CA) 1 were completely lost whereas moderate neuron loss was also observed in sectors CA3 and 4, and the dentate gyrus. Neurons of sector CA2 were relatively well preserved and the subiculum was intact. There was no evidence of global hypoxia, or of neurodegenerative disorders with pathological changes affecting the hippocampus. Although there was a long preneoplastic history, and no inflammatory changes were found at autopsy, the present case of hippocampal sclerosis could be included in the category of paraneoplastic limbic encephalitis associated with Hodgkin's lymphoma or the Ophelia syndrome.

Trends in cancer mortality in the European Union and accession countries, 1980-2000

Cancer mortality rates and trends over the period 1980-2000 for accession countries to the European Union (EU) in May 2004, which include a total of 75 million inhabitants, were abstracted from the World Health Organization (WHO) database, together with, for comparative purposes, those of the current EU. Total cancer mortality for men was 166/100,000 in the EU, but ranged between 195 (Lithuania) and 269/100,000 (Hungary) in central and eastern European accession countries. This excess related to most cancer sites, including lung and other tobacco-related neoplasms, but also stomach, intestines and liver, and a few neoplasms amenable to treatment, such as testis, Hodgkin's disease and leukaemias. Overall cancer mortality for women was 95/100,000 in the EU, and ranged between 100 and 110/100,000 in several central and eastern European countries, and up to 120/100,000 in the Czech Republic and 138/100,000 in Hungary. The latter two countries had a substantial excess in female mortality for lung cancer, but also for several other sites. Furthermore, for stomach and especially (cervix) uteri, female rates were substantially higher in central and eastern European accession countries. Over the last two decades, trends in mortality were systematically less favourable in accession countries than in the EU. Most of the unfavourable patterns and trends in cancer mortality in accession countries are due to recognised, and hence potentially avoidable, causes of cancer, including tobacco, alcohol, dietary habits, pollution and hepatitis B, plus inadequate screening, diagnosis and treatment. Consequently, the application of available knowledge on cancer prevention, diagnosis and treatment may substantially reduce the disadvantage now registered in the cancer mortality of central and eastern European accession countries.

Trends in mortality from major cancers in the European Union, including acceding countries, in 2004

BACKGROUND

In May 2004, 10 additional countries joined the European Union (EU), including a total of 75 million inhabitants. Most of these were from central and eastern European countries with comparably high cancer mortality rates and with relatively unfavorable trends. Therefore, it is important to provide updated mortality data regarding major cancers in various countries and to analyze trends for the current population of the EU.

METHODS

The authors considered mortality rates (directly standardized to the world standard population) for all cancers and for 8 major cancer sites in the year 2000 in the 25 countries of the EU and analyzed corresponding trends since 1980 using data derived from the World Health Organization data base.

RESULTS

For men, overall cancer mortality in the year 2000 varied by a factor > 2 between the highest rate of 258.5 per 100,000 men in Hungary and the lowest rate of 122.0 per 100,000 men in Sweden. Central and Eastern European accession countries had the highest rates not only for lung and other tobacco-related cancers but also for gastrointestinal cancers and leukemias. The geographic pattern was different and the range of variation was smaller for women, i.e., between 136.7 per 100,000 women in Denmark and 76.4 per 100,000 women in Spain in the year 2000. In the EU as a whole, lung cancer mortality in men peaked at 55.4 per 100,000 men in 1988 and declined thereafter to 46.7 per 100,000 men in 2000. Gastric cancer steadily declined from 19.7 per 100,000 men in 1980 to 10.1 per 100,000 men in 2000. Other major sites showed moderately favorable trends over the last few years. In women, breast cancer peaked at 21.7 per 100,000 in 1989 and declined to 18.9 per 100,000 in 2000. Mortality from gastric, (cervix) uterus, and intestinal cancers demonstrated steady decreases, but lung cancer increased from 7.7 per 100,000 women in 1980 to 11.1 per 100,000 women in 2000. The increase in lung cancer mortality in women age < 55 years was 38% between 1990 and 2000 (from 2.16 per 100,000 women to 2.99 per 100,000 women), reflecting the spread of tobacco smoking among women in the EU over the last few decades.

CONCLUSIONS

The priority for further reduction of cancer mortality in the EU remains tobacco control together with more widespread availability of modern diagnostic and treatment procedures for neoplasms that are amenable to treatment.

Cancer mortality in Europe, 1995-1999, and an overview of trends since 1960

Mortality data, abstracted from the World Health Organization database, are presented in tabular form for 26 cancer sites or groups of sites, plus total cancer mortality, in 36 European countries during the period 1995-1999. Trends in mortality are also given in graphic form for 23 major countries plus the European Union as a whole over the period 1960-1999. In the European Union, total cancer mortality declined by 7% for both sexes over the last 5 years considered. The fall since the late 1980s was 10% in both sexes, corresponding to the avoidance of over 90000 deaths per year, as compared to the rates of the late 1980s. For the first time, over the last few years, some leveling of mortality was reported also in the Russian Federation, the Czech Republic, Poland, Hungary and other Eastern European countries, although cancer rates in those areas remain exceedingly high. The overall favorable pattern of cancer mortality over recent years is largely driven by the decline of tobacco-related cancer mortality in men. However, important components of the trends are also the persistence of substantial falls in gastric cancer, mainly in Russia and Eastern Europe, the recent decline in intestinal cancer in both sexes and of breast cancer in women, together with the long-term falls in uterine (cervical) cancer, leukemias, Hodgkin's disease and other neoplasms amenable to advancements in diagnosis and treatment. Female lung cancer mortality has been declining in the Russian Federation, but is still rising in other areas of the continent. Thus, urgent intervention is needed to bring under control the tobacco-related lung cancer epidemic in European women before it reaches the high level observed in North America. Supplementary material for this article can be found on the International Journal of Cancer website at http://www.interscience.wiley.com/jpages/0020-7136/suppmat/index.html

Anaesthetic implications of anticancer chemotherapy

In anaesthetic practice we deal with cancer patients who are scheduled for operations on tumours or other manifestations of malignant disease. Those patients are often debilitated and have significant weight loss accompanied with hypoproteinaemia, anaemia and coagulation disorders. Oncological patients usually present to the anaesthetist before tumour disease surgery, but they are also candidates for elective operations (e.g. hernia repair) and urgent/emergency surgery (e.g. trauma, fractures and ileus). Chemotherapeutic agents given to these patients are potentially noxious, can affect the conduct of anaesthesia and, furthermore, may aggravate the patient's condition. In this review the most commonly used cytostatic drug regimens and their common side-effects are listed. Some preclinical studies on anaesthetic and cytostatic drug metabolism and interactions are emphasized, as well as clinically relevant perioperative alterations that may affect anaesthetic management in cancer patients. An anaesthetist may have to modify a routine anaesthetic regimen in cancer patients especially if anticancer chemotherapeutics were given. Clinically silent toxic drug effects may become apparent during operation, trauma or in the early postoperative course in such patients. Altered reactions to commonly used anaesthetics in patients receiving chemotherapeutics and an impaired stress reaction may occur in such patients. Special attention must be drawn to protection against opportunistic infections.

Trends in incidence of and mortality from cancer in The Netherlands in the period 1989-1998

This paper summarises the population-based major trends in cancer incidence and mortality in the period 1989-1998 in The Netherlands. Trends of the European age-adjusted incidence and mortality rates were estimated by the Estimated Annual Percentage Change (EAPC) method. Increases in incidence were found for cancer of the breast and lung for females. For males, an increase was observed for cancer of the prostate, colon, rectum and testis. In both groups, oesophageal and pharyngeal cancer increased, but that of stomach and gallbladder cancer decreased. The main increases in mortality were found for pharyngeal cancer in males, lung in females and oesophageal cancer in both sexes. Decreases were shown for stomach cancer for both sexes and lung cancer for males. Trends in incidence may be a result of changes in behaviour, smoking habits in preceding decades are related to the increase in lung cancer for females, and early detection, screening programmes increased the incidence for breast and prostate cancers. Decreases in mortality may be related to more successful treatment of leukaemia, Hodgkin's lymphoma, colorectal and testicular cancers. Primary prevention of cancer remains important.

Trends in cancer mortality at age 15 to 24 years in Europe

Trends in death certification rates from all cancers and seven selected cancer sites (bone sarcoma, soft-tissue sarcoma, ovary, testis, non-Hodgkin's lymphomas, Hodgkin's disease, leukaemias) were analysed for the population aged 15-24 years in Europe and, for comparative purposes, in the United States of America (USA) and Japan over the period of 1965-1998. Overall, there was a decrease in total cancer mortality of approximately 40% for both sexes. The declined mortality is largely attributable to better treatments and inclusion in multicentre clinical trials. The degree of improvement was similar in Japan and the USA, but was less in Eastern European countries, reflecting delays in the application of effective treatments, and limited involvement in large, well-designed clinical trials for these curable cancers in Eastern Europe.

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.