world cancer report - iarc

Fig. 5.98 Non-Hodgkin lymphoma in the neck of a
patient suffering from AIDS.
Americans than that of black Africans,
suggesting that socioeconomic conditions
may be more important than ethnicity in
determining risk. In developed countries,
incidence has fallen in the last 20 years
[1]. Mortality rates are also decreasing,
probably due to effective therapy.
Etiology
Non-Hodgkin lymphoma
Patients with HIV/AIDS (Box: Tumours
associated with HIV/AIDS, p60), or who
have received immunosuppressant therapy
(Immunosuppression, p68), have a
higher risk of developing non-Hodgkin
lymphoma [2]. Viral infections such as
HIV-1, HTLV-1 and EBV are also associated
with non-Hodgkin lymphoma. Infection
of the stomach with Helicobacter pylori is
associated with gastric lymphoma.
Agricultural work with possible exposure
to pesticides (particularly chlorophenoxy
herbicides) and occupational exposure to
solvents or fertilizers have been implicated
but have yet to be confirmed as causes
of non-Hodgkin lymphoma.
There is an increased risk of non-Hodgkin
lymphoma among persons with a family
history of lymphoma or haematologic cancer
[2].
Hodgkin disease
A subset of Hodgkin disease cases, particularly
the mixed cellularity type, has been
linked to the Epstein-Barr virus (EBV) [2].
Overall, around 45% of cases may be attributable
to EBV. The presence of EBV in
tumours seems also to be related to age and
socioeconomic circumstances. EBV is
involved in the etiology of Burkitt lymphoma,
238 Human cancers by organ site
Fig. 5.99 Trends in incidence of non-Hodgkin lymphoma in the USA. Rates are increasing, as they are
worldwide.
especially in cases in tropical Africa, where
over 95% of tumours contain the virus. The
proportion of EBV-positive tumours is much
less in the sporadic cases of Hodgkin disease
occurring in Europe and North
America. The singular geographic distribution
of Burkitt lymphoma is not explicable on
the basis of EBV alone, however, since infec-
< 0.8 < 1.7 < 2.1 < 2.7
tion by the virus is ubiquitous. Suspicion has
fallen upon intense malaria infection as predisposing
to Burkitt lymphoma in the presence
of EBV infection. Chronic exposure to
wood or wood products has also been associated
with increased risk. The risk of
Hodgkin disease is also increased in
patients with HIV infection.
Age-standardized incidence/100,000 population
Fig. 5.100 Global incidence of Hodgkin disease in men. The disease is rare in Eastern and South-Eastern
Asian populations.
8.0