Epidemiology of non-Hodgkin lymphoma in Connecticut. 1935-1988.

BACKGROUND. During the past decades, there have been reports of increases in the incidence and mortality rates due to non-Hodgkin lymphoma (NHL) in many parts of the world. The risk factors responsible for the increasing incidence are largely unknown. This study provided an overview of the incidence pattern of NHL in Connecticut and generated hypotheses for additional investigation. METHODS. This study was based on all the NHL cases reported to the Connecticut Tumor Registry (CTR) between 1935 and 1988. Crude, age-adjusted, and age-specific incidence rates of NHL were calculated for each sex. Age-adjusted incidence rates were calculated by the direct method standardized to the 1970 United States standard million population. The data are presented by calendar year and cohort year of birth to examine the secular trends and birth cohort effects. Racial information was not coded before 1957 and is of uncertain validity until the early 1970s; therefore, racial analysis was restricted to 1970-1988. Analyses by histologic subtypes and by anatomic sites were restricted to the last 3 decades (1960-1988) because more accurate classification systems were used during this time. RESULTS. A total of 11,326 newly diagnosed cases of NHL were included in the study. Of them, 5866 (52%) were diagnosed in men and 5460 (48%) were diagnosed in women. The study results indicated that the incidence rate of NHL has been increasing during the past decades for men and women, whites and blacks, nodular NHL and diffuse NHL, disease originating from lymph nodes and disease originating from other sites, and in all age groups, especially the older age groups. Birth cohort examination did not show any indication of a decline or levelling off in incidence rates among recent birth cohorts. Age-specific incidence rates in both sexes suggested that the rates increase with age, with a sharp increase beginning at 50 years of age and peaking at 80 years of age. Men had a 30% higher incidence rate than women, and whites had approximately 1.5 times the age-adjusted incidence rate of blacks. CONCLUSIONS. The results indicated that the incidence rate of NHL has been increasing in Connecticut during the past decades and is likely to continue to rise in the coming years. Analytical epidemiologic studies are needed to examine the risk factors that might account for the increase in NHL.     

Trends in lung cancer incidence in Sweden with special reference to period and birth cohorts

Objective: Sweden has one of the largest population-based cancer registers in the world that provides an opportunity to examine the trend of lung cancer incidence during a 35-year period. The primary aim of the present study was to estimate the effects of birth cohort, year of diagnosis (period), and age on the time trends of lung cancer incidence rates, and to analyze the gender-specific incidence of different histopathological types of lung cancer. Results: Among men the age-standardized incidence rate increased steadily up to 1982, when a peak of 49 cases per 100,000 person-years was reached. Among women the incidence rate was lower and showed a monotonic increase throughout the observation period. The fastest rate of increase was noted among the youngest women. In women, but not in men, there was a steady increase in risk with each successive birth cohort. For both sexes there were large changes in the histopathological distributions of cases. The most notable was a major increase in adenocarcinomas. Conclusions: The overall age-adjusted incidence rate of lung cancer in Sweden has stabilized in men during the past two decades while rates are still increasing in women. In view of the continued high prevalence of smoking among young women, a future definite increase in the overall number of lung cancer cases in women can be expected.     

Bronchogenic carcinoma in Olmsted County, 1935-1979

The incidence rates of bronchogenic carcinoma based upon 414 cases that occurred in Olmsted County, Minnesota, over a period of 45 years are described. Histologic preparations were available for 97% of cases and were reviewed by one pathologist. The overall average annual age-adjusted rates per 100,000 person-years for the most recent 5 years were 45.6 and 14.0 for men and women, respectively. Squamous cell carcinoma was most common among men and adenocarcinoma was the most common cell type among women. Incidence rates for women have risen to approximately those of men 30 years ago, whereas the incidence for men in the last 5 years has ceased to increase. Age-specific rates show increases for women in all age groups 55 years and older, and for men 65 years and older, whereas the incidence in men younger than 65 years has declined. Survival for 5 years is best for women for all cell types except small cell carcinoma, and is essentially unchanged from the earlier 40-year report.     

Trends in the incidence of cancer in Kampala,Uganda 1991–2010

The Kampala cancer registry is the longest established in Africa. Trends in incidence rates for a 20‐year period (1991–2010) for Kyadondo County (Kampala city and a rural hinterland) illustrate the effects of changing lifestyles in urban Africa, and the effects of the epidemic of HIV‐AIDS. There has been an overall increase in the risk of cancer during the period in both sexes, with incidence rates of major cancers such as breast and prostate showing particularly marked increases (3.7% and 5.2% annually, respectively). In the 1960s cancer of the oesophagus was the most common cancer of men (and second in women), and incidence in the last 20 years has not declined. Cancer of the cervix, always the most frequent cancer of women, has shown an increase over the period (1.8% per year), although the rates appear to have declined in the last 4 years. HIV prevalence in adults in Uganda fell from a maximum in 1992 to a minimum (about 6%) in 2004, and has risen a little subsequently, while availability of antiretroviral drugs has risen sharply in recent years. Incidence of Kaposi sarcoma in men fell until about 2002, and has been relatively constant since then, while in women there has been a continuing decline since 2000. Other HIV related cancers—non‐Hodgkin lymphoma of younger adults, and squamous cell carcinoma of conjunctiva—have shown major increases in incidence, although the former (NHL) has shown a small decline in incidence in the most recent 2 years.     

Colorectal cancer incidence, mortality and survival in South-east England between 1972 and 2001.

We report incidence, mortality and survival from colorectal cancer in South-east England using data from 162,022 incident cases and 97,697 deaths collected between 1972 and 2001 at the Thames Cancer Registry, which currently covers 14 million people. Overall, there was an increase in the incidence of colorectal cancer among men aged 50 years and over, and a decrease among the youngest age groups. In women, there was a clear decrease in incidence among those aged less than 60 years but a slight increase among those aged 60-79 years. Furthermore, there has been a steady decrease in mortality for all ages, larger in women than in men, and an increase in the 10-year relative survival for both sexes from just over 30% among those followed-up during 1981-1986 to just over 45% among those followed-up during 1997-2001.     

Recent trends and future projections of lymphoid neoplasms – a Bayesian age–period–cohort analysis

Objectives: A steady increase in incidence of lymphoid neoplasms has been reported, especially for non-Hodgkin's lymphoma (NHL). Using high-quality incidence data from 1973–1992 in nine population-based cancer registries (Alberta, Bombay, Denmark, Israel, New Zealand, Osaka, Oxford, Slovenia, Utah), we have examined past increases in specific lymphoid neoplasms. Further, by using a Bayesian age–period–cohort approach, we have calculated 5-, 10- and 15-year projections for each group of lymphoid neoplasms. Results: NHL incidence increased in all centers by an average of 77% in men and 66% in women between 1973 and 1992. Fifteen-year projections of these rates to 2003–2007 indicate that they will increase by an average of 55% among men and 79% among women. High projected incidence rates above 15/100,000 in men and 10/100,000 in women are expected in Alberta, Denmark, Israel, New Zealand, Oxford, and Utah by 2003–2007. The one notable exception was among men from Osaka, where no increase was projected. Modest increases in leukemia and multiple myeloma rates were observed in most of the nine registries with further projected increases by 2007. Projected incidence rates of Hodgkin's disease indicated little change. Conclusion: Increases in NHL rates are occurring worldwide and provide no evidence of peaking. A key assumption in the projected rates is that the effect of environmental agents determining the trends during 1973–1992 will remain stable during the subsequent projection period.     

Changing incidence of non-Hodgkin lymphomas in the United States

BACKGROUND: The incidence of non-Hodgkin lymphoma (NHL) has been rising in many regions and populations during the last few decades. Data from the Surveillance, Epidemiology, and End Results (SEER) Program show that age-adjusted rates of NHL increased through the 1980s but leveled off in the 1990s. METHODS: To determine whether the incidence of NHL stabilized in all population subgroups, particularly in age-defined groups with distinctive risks of NHL, the authors investigated trends in NHL incidence among persons aged 0-14 years, 15-24 years, 25-34 years, 35-44 years, 45-54 years, 55-64 years, 65-74 years, and > 75 years by gender and race using 1973-1998 data from the SEER Program, which covered approximately 10% of the U.S. population. Joinpoint regression was used to assess changes in trends across the period. RESULTS: NHL incidence trends changed significantly among males aged 25-54 years, in whom rates began to decrease (6-16% per year) in the middle to late 1990s, as well as among most whites aged > or = 55 years, in whom rate increases slowed from 3-4% to 1-2% per year in the late 1980s. Incidence trends were steady in other groups, with uniform increases among whites aged 15-24 years (2-3% per year), women aged 25-54 years (1-6% per year), and blacks aged > or = 55 years (2-4% per year). Although recent age specific incidence rates were generally higher in males compared with females and in whites compared with blacks, among males aged 25-54 years, rates were significantly higher in black males compared with white males. CONCLUSIONS: There have been changes in the demographic groups impacted by NHL. The trends for human immunodeficiency virus probably are related to recent decreases in NHL incidence among males aged 25-54 years. The rate change in the older white population is unexplained but represents both an alleviation of the burden of NHL in this population and a potential opportunity to generate hypotheses regarding risk factors for the development of NHL.     

Non-Hodgkin's lymphoma: an analysis of the Metropolitan Detroit SEER database

We evaluated incidence and survival trends of non-Hodgkin's lymphoma (NHL) in a large population-based cancer registry. Data regarding demographics, histology, incidence, and survival were obtained on all patients with NHL registered in the Metropolitan Detroit Cancer Surveillance System, a participant in the Surveillance Epidemiology and End Results (SEER) Program of the National Cancer Institute. Incidence and survival trends from 1973 through 1995 were evaluated and stratified based on age at diagnosis, sex, race, and tumor grade. There were 11,978 patients diagnosed with NHL and recorded in the Metropolitan Detroit SEER registry from 1973 to 1995. The age-adjusted incidence rate increased from 8.6 to 15.8 per 100,000, leading to an overall increase in incidence of 83% and an average annual increase of 3.2% per year. Incidence increased significantly (p < 0.05) over time in all age groups except the youngest (ages 0-19) and in all demographic groups studied. Incidence was highest in white men and lowest in black women. The incidence of both low-grade and intermediate/high-grade NHL increased significantly for each age group (p < 0.05) except the youngest (ages 0-19). In the oldest patients (70+ years), the incidence of intermediate/high-grade NHL was almost double that of low-grade NHL. Five-year relative survival increased from 64% (1973-1983) to 68% (1984-1991) for patients with low-grade NHL and from 40% to 44% for those with intermediate/high-grade NHL. The increase in relative survival was only seen in whites, however, with 5-year relative survival in blacks decreased from 53% (1973-1983) to 45% (1984-1991). In metropolitan Detroit, the current NHL epidemic affects all age groups except the very young (ages 0-19), both sexes, and both whites and blacks and is due to increases in the incidence of both low-grade and intermediate/high-grade NHL. Five-year survival rates have increased for whites but not for blacks.     

Effect of organised screening on cervical cancer incidence and mortality in Finland, 1963-1995: recent increase in cervical cancer incidence.

A nation-wide screening programme for cervical cancer started in Finland gradually from 1963 onwards. By the beginning of the 1990s, there had been a decrease of 80% both in the age-adjusted incidence of and mortality from cervical cancer. To describe the recent patterns in cervical cancer incidence and mortality and evaluate their differentials in relation with the organised screening activities, we have updated the material on the cervical cancer incidence and mortality as well as mass-screening activities up to the year 1995. Based on the files of the Finnish Cancer Registry, there is a striking increase of about 60% in the incidence of cervical cancer during the last 4 years of the study period among women below 55 years of age. The mortality rates are still decreasing. There is no overall decrease over recent years in the coverage of the programme invitations or smears taken. Incidence of invasive cancer and of moderate and severe dysplasia as detected in mass screening have increased. As to the interpretation, changes in the risk factors, such as in sexual behaviour and smoking habits, over the decades might partly explain increasing trends in cervical cancer incidence. As the change in incidence was relatively abrupt, inadequacies or changes in the effectiveness in the screening programme, particularly among young women, may also have contributed. Expanding the coverage of and attendance in the pap-screening programme among women in young target ages would still be effective. Increasing emphasis on quality assessment in screening is also needed.     

Acquired immune deficiency syndrome and the increase in non-Hodgkin lymphoma incidence in New Jersey from 1979 to 1996.

BACKGROUND: In New Jersey, the age-adjusted incidence rate of non-Hodgkin lymphoma (NHL) increased more than a third from 1979 to 1996, the largest increase among the major cancers. METHODS: Data from a linkage of New Jersey's population-based cancer and acquired immune deficiency syndrome (AIDS) registries were used to obtain two sets of annual age specific incidence rates and estimated average annual percentage changes in the incidence rates, for each of five adult age groups within each gender, from Poisson regression models that 1) included all the NHL cases and 2) excluded the cases of AIDS-NHL. RESULTS: During 1979-1996, of the NHL cases aged 15 years and older reported to the cancer registry, 687 (6%) of the 11,725 male cases and 139 (1%) of the 10,785 female cases were AIDS-NHL. The highest percentages of AIDS-NHL were in the younger age groups--15-29, 30-39, and 40-49 years. Among both men and women, average annual percentage increases in NHL occurred overall (3.1 and 3.0, respectively), and in each age group, ranging from 1.6 and 1.9, respectively, in the 50-59 years age group to 6.6 and 4.2, respectively, in the 30-39 years age group (P <0.01). Excluding AIDS-NHL, the estimated average annual percentage increases in NHL were greatest in the 30-39 and the 60 years and older age groups among men, and these two age groups plus the 15-29 years age group among women, ranging between 2.4 and 2.9 (P < 0.05). CONCLUSIONS: As elsewhere, factors in addition to AIDS are involved in the increasing incidence of NHL in New Jersey. Because diagnostic and classification changes probably do not explain the entire increase unrelated to AIDS, other risk factors are likely responsible. Public health interventions to reduce the incidence of NHL not related to AIDS are problematic until more is known about the causes of NHL.     

Recent increase in the incidence of non-Hodgkin's lymphoma among young men and women in Denmark.

Time-related trends in the incidence of non-Hodgkin''s lymphoma (NHL) in Denmark were analysed for the period 1943-89. A total of 13 822 patients (7565 men and 6257 women) were included in the study. In men, world-standardised incidence rates per 100 000 population increased from 2.5 in 1943-47 to 9.3 in 1988-89. In women, a similar increase was seen, i.e. from 1.9 in 1943-47 to 6.5 per 100 000 population in 1988-89. For all birth cohorts, the male-to-female incidence ratio was highest among young subjects and fell significantly after the age of 29 years. Trends in age-specific incidence were analysed separately for two periods, i.e. 1943-77 and 1978-89, reflecting an early, pre-AIDS period and a later period possibly influenced by AIDS. In both periods, the incidence of NHL increased in all age groups. However, in recent years a noticeable increase in incidence averaging 8% annually was observed in men and women aged 40-49 years. A number of factors including changes in the perception of NHL and in the diagnostic methods available are considered insufficient to explain the observed increase. The remarkable and parallel time trends observed in young men and women in recent years indicate that factors other than AIDS must be considered.     

Intraoral squamous cell carcinoma. Epidemiologic patterns in Connecticut from 1935 to 1985

There were 6181 cases of invasive intraoral squamous cell carcinoma accessioned by the Connecticut State Tumor Registry from 1935 to 1985. Cases were analyzed for age, sex, lesion site, and histologic differentiation. Crude, age-specific, and age-adjusted incidence rates plus birth cohort analyses were also calculated. It was found that incidence rates for both men and women increased over the 51-year period of study. For men, age-adjusted incidence rates (1970 United States standard) increased from 4.9/100,000 in 1935 to 1939 to 8.5/100,000 in 1980 to 1985; for women, rates increased from 0.5/100,000 to 3.3/100,000 for the same period. The male-to-female ratio for intraoral squamous cell carcinoma declined dramatically from 9.8 to 2.6 during the 51-year study period primarily because of the steep rate of increased incidence in women relative to that seen in men. The peak age of intraoral squamous cell carcinoma was the seventh decade. Age-specific analysis showed that the older the age group, the higher the incidence for both sexes. During recent years, there was evidence of slightly increased incidence in men younger than 40. The tongue was the most common site for intraoral squamous cell carcinoma, followed closely by the floor of the mouth. Moderately differentiated tumors were most common (54.3% of the total), followed by both well-differentiated cases (29.1%) and those that were poorly differentiated (16.6%).     

Increasing incidence of non-Hodgkin's lymphoma in Canada, 1970-1996: age-period-cohort analysis

Previous studies have shown that the incidence of non-Hodgkin's lymphoma (NHL) has increased in many parts of the world in recent decades. Using data obtained from the Canadian Cancer Registry, the present study examined time trends in NHL incidence in Canada between 1970 and 1996 and the effects of age, period of diagnosis and birth cohort on incidence patterns for each sex separately. Results showed that overall age-adjusted incidence rates increased substantially, from 7.3 and 5.2 per 100,000 in 1970-1971 to 14.0 and 10.0 per 100,000 in 1995-1996 in males and females, respectively. Diffuse lymphoma was the major histological subtype, accounting for approximately 76% of NHL cases over the 27-year period. The data suggest that period effects have played a major role, although birth cohort effects may also have been involved. Sex-specific patterns of the incidence were similar over the time period of diagnosis but were distinct among recent birth cohorts. In conclusion, there is in fact a marked increase in NHL in Canada which cannot be explained in terms of improvements in diagnosis, changes in NHL classification and the increase in AIDS-associated NHL alone. The birth cohort effect in NHL suggests that changes in risk factors may have contributed to the observed increase.     

Increase in incidence rates of basal cell and squamous cell skin cancer in New Hampshire, USA. New Hampshire Skin Cancer Study Group

We conducted a study to estimate the current incidence rates of basal-cell carcinoma (BCC) and squamous-cell carcinoma (SCC) of the skin in the population of New Hampshire (NH), USA, and to quantify recent changes in the incidence rates of these malignancies. BCCs and SCCs diagnosed among NH residents were identified through physician practices and central pathology laboratories in NH and bordering regions from June 1979 through May 1980 and from July 1993 through June 1994. For each diagnosis period, we estimated the age-adjusted incidence rates for both BCC and SCC among both men and women and for separate anatomic sites. Between 1979-1980 and 1993-1994, incidence rates of SCC increased by 235% in men and by 350% in women. Incidence rates of BCC increased by more than 80% in both men and women. While the absolute increase was greatest for tumors of the head and neck, the relative change was most pronounced for tumors on the trunk in men and on the lower limb in women. Thus, there has been a marked rise in the incidence rates of BCC and SCC skin cancers in NH in recent years. The anatomic pattern of increase in BCC and SCC incidence is consistent with an effect of greater sunlight exposure. Studies of BCC and SCC occurrence are needed to identify possible behavioral and environmental factors and to assess possible changes in diagnostic practices that might account for the rise in incidence of these common malignancies.     

Interpreting trends of pancreatic cancer incidence and mortality: a nation-wide study in Sweden (1960–2003)

Objective We investigated temporal trends of pancreatic cancer in Sweden measured with suboptimal sensitivity and specificity both by incidence and by mortality rates. Methods 46,257 incident cases of pancreatic cancer from the Swedish Cancer Register and 53,686 mortality cases from the Causes of Death Register during 1960–2003 were used to calculate age-standardized incidence or mortality rates. We further assessed the impact of changes in diagnostic practice on the observed trends, and investigated the effect of calendar period and birth cohort by age-period-cohort modeling. Results Overall, the pattern of trends in age-adjusted rates of pancreatic cancer was similar irrespective of whether incidence or mortality was used. The age-adjusted rates of pancreatic cancer increased during the first decade and then peaked for both sexes (the male peak occurred in the early 1970s and the female peak in the1980s) followed by a steady decline in both groups. An age-period model provided the best fit to the observed trends among patients diagnosed at ages 35–74 in both sexes. Conclusion The close agreement between the incidence and mortality and the gender disparity suggest a true decline in pancreatic cancer incidence in recent years in Sweden, and gender-specific trends in exposure to environmental risk factors.     

Dietary factors and risk of non-hodgkin lymphoma in men and women.

BACKGROUND: The incidence of non-Hodgkin lymphoma (NHL) has increased worldwide in recent decades. Diet could influence NHL risk by modulating the immune system, although evidence is limited. We did a population-based case-control study to determine whether differences in diet were associated with NHL risk. METHODS: A total of 597 NHL cases and 467 population controls in Sweden completed a semiquantitative food frequency questionnaire evaluating their dietary habits 2 years before the interview. Unconditional logistic regression was used to estimate the odds ratios (OR) and corresponding 95% confidence intervals (95% CI) for associations between food intake and risk of NHL. RESULTS: High consumption of dairy products and fried red meat was associated with increased risk of NHL. The OR of NHL for individuals in the highest quartile compared with the lowest quartile of dairy intake was 1.5 (95% CI, 1.1-2.2; P(trend) = 0.003). The OR for the highest versus lowest quartile of fried red meat intake was 1.5 (95% CI, 1.0-2.1; P(trend) = 0.02). In contrast, high consumption of fruits and vegetables was associated with reduced risk of NHL, particularly follicular lymphoma, among women but not men. Compared with the lowest quartile of vegetable intake, the OR of follicular lymphoma among women in the highest quartile of vegetable intake was 0.3 (95% CI, 0.1-0.7; P(trend) = 0.002). CONCLUSIONS: The positive associations of NHL risk with dairy products and fried red meat and the inverse association with fruits and vegetables suggest that diet affects NHL risk and could explain the increase of some histopathogic subtypes.     

Trends in the incidence of ovarian cancer and borderline tumours in Norway, 1954-1993

Histology-specific long-term trends in the incidence of ovarian cancer and borderline tumours in Norway were examined, based on data from the population-based Cancer Registry of Norway. A total of 14,352 cases of ovarian cancer were diagnosed between 1954-1993, of which 94%of the histologically verified ovarian cancers were epithelial tumours. The age-adjusted incidence rate rose from 10 per 100,000 person-years in 1954-1958 to a peak of 14 per 100,000 person-years in 1984-1988. In women older than 50 years, there was an increasing trend in incidence rates during the entire study period. From the cohort perspective, the largest increase was observed among women born between 1870-1899. A total of 2,343 borderline tumours was diagnosed between 1970-1993. The age-adjusted incidence rate has increased since 1970, reaching 4.8 per 100,000 person-years in 1989-1993. Int. J. Cancer 71: 780-786, 1997. © 1997 Wiley-Liss Inc.     

Autoimmune diseases associated with non-Hodgkin lymphoma: a nationwide cohort study

BackgroundThe cumulative risk of non-Hodgkin lymphoma (NHL) in Sweden by age 80 years has increased to 1.1 in women and 1.6% in men in 2011. Increased risk of NHL associated with personal histories of some autoimmune diseases (ADs) is known. It is unclear whether there are other NHL-related ADs and whether this association holds across different sex, age and year of diagnosis, or NHL histological subtypes.Patients and methodsOver an average of 9.4-year (maximum 47 years) follow-up of 878 161 patients diagnosed in 1964–2010 with 33 different ADs, 3096 subsequent NHL were diagnosed (data: Swedish Cancer Registry).ResultsOf 33 studied ADs, 21 showed significantly increased risk of NHL; 6 of them tended to increase the risk and none significantly decreased it. The overall standardized incidence ratio (SIR) for NHL after ADs was 1.6 [novel findings: immune thrombocytopenic purpura (ITP) = 7.5, polymyositis/dermatomyositis = 4.1, primary biliary cirrhosis = 3.9, myasthenia gravis = 2.2, Behcet = 1.7, rheumatoid fever = 1.7, ulcerative colitis = 1.5, polymyalgia rheumatica = 1.4, and chronic rheumatic heart disease = 1.4; confirmatory findings: autoimmune hemolytic anemia = 27.2, Sjögren = 4.9, Celiac = 4.8, systemic lupus erythematosus = 4.4, polyarteritis nodosa = 2.9, discoid lupus erythematosus = 2.7, sarcoidosis = 2.6, Crohn = 2.1, systemic sclerosis = 2.1, rheumatoid arthritis = 2.0, and Hashimoto/hypothyroidism and psoriasis = 1.4]. SIR for NHL diagnosis before age 60 (2.2) was significantly higher than that in older ages (age ≥60: 1.5). The SIRs in women or men and in period 1993–2010 or 1964–1992 were similar. Risk of all common NHL histology subtypes significantly increased after ADs (cutaneous/peripheral T cell and anaplastic large T and null cell = 2.2; small B-cell lymphocytic = 1.7; diffuse large B cell = 1.6; follicular and mantel cell = 1.3).ConclusionMany of 33 studied ADs (except for ankylosing spondylitis, diabetes type I graves/hyperthyroidism, multiple sclerosis, chorea minor, and pernicious anemia), especially when diagnosed at younger ages, were associated with higher risk of NHL. However, the absolute risk of NHL in many ADs is still small.     

Gender and time differences in initial location and histological grade of non-Hodgkin's lymphomas in Southern Sweden

In accordance with international data, non-Hodgkin's lymphomas (NHL) in the Southern Health Care Region of Sweden were more common in men than in women and there was an inreasing incidence for both genders in the 1980s and 1990s. A study of the years 1983 and 1992, i.e. the beginning and the end of a 10-year period, was carried out. Case records for 94% of all adults diagnosed in 1983 and 1992 (220 men and 171 women) were reviewed. The sites of the lymphomas and malignancy grade (Kiel classification) were recorded. Comparisons were made between the genders and between the two years studied. Among 170 men with nodal lymphomas, 49 were localized (stage I-II) in lymphoid tissue regional to the respiratory tract, 18 were localized elsewhere and 103 were generalized (stage III-IV). The corresponding sites in 138 women were 28, 33 and 77, respectively (p = 0.002), implying a predominance of stage I-II lymphomas regional to the respiratory tract in men and a larger number of localized lymphomas elsewhere, mostly abdominal/retroperitoneal with or without inguinal engagement in women. High-grade nodal lymphomas were more common in 1992 (54%) than in 1983 (34%, p = 0.01), suggesting an increasing number of mainly high-grade lymphomas. For extranodal lymphomas (50 in men and 33 in women), no clear differences were observed for gender and the years studied. Risk factors, e.g. occupational hazards, are probably different for men and women. The gender differences in initial nodal location suggest that initial lymphoma sites may be related to different risk factors. Epidemiologic studies where both malignancy grade and initial lymphoma locations are taken into account may be helpful in defining risk factors.