1. ¹International Agency for Research on Cancer, 69008 Lyon, France
2. ²German Cancer Research Center, 69120 Heidelberg, Germany
3. ³Department of Biosciences at Novum, Karolinska Institute, 14157 Hudinge, Sweden
4. ⁴Institute of Cancer Epidemiology, Danish Cancer Society, 2100 Copenhagen, Denmark
5. ⁵New South Wales Cancer Registry, 2015 Eveleigh, New South Wales, Australia
6. ⁶Institute of Population-Based Cancer Research, 0310 Oslo, Norway
7. ⁷Scottish Cancer Registry Information Services, NHS National Services Scotland, EH53SQ Edinburgh, Scotland
8. ⁸Finnish Cancer Registry, Institute for Statistical and Epidemiology Cancer Research, 00170 Helsinki, Finland
9. ⁹Cancer Control Research Programme, British Columbia Cancer Agency, V5Z4E6 Vancouver, British Columbia, Canada
10. ¹⁰Epidemiology and Cancer Registry, CancerCare Manitoba, R3E0V9 Winnipeg, Canada
11. ¹¹Community Health Sciences, University of Manitoba, R3E0V9 Winnipeg, Canada
12. ¹²Program Evaluation and Surveillance, Saskatchewan Cancer Agency, S4T7T1 Regina, Saskatchewan, Canada
13. ¹³Center for Molecular Epidemiology, 117597 Singapore, Singapore
14. ¹⁴Cancer Registry of Slovenia, Institute of Oncology, 1105 Ljubljana, Slovenia
15. ¹⁵Cancer Registry of Zaragoza, Health Department of Aragon Government, 50004 Zaragoza, Spain
16. ¹⁶Icelandic Cancer Registry, Icelandic Cancer Society, 125 Reykjavik, Iceland
17. ¹⁷Faculty of Medicine, University of Iceland, 125 Reykjavik, Iceland

Correspondence: Dr P Brennan, Genetic Epidemiology Group, Genetics and Epidemiology Cluster, International Agency for Research on Cancer (IARC), 150 Cours Albert Thomas, 69008 Lyon, France. E-mail: brennan@iarc.fr

Received 7 February 2005; Revised 18 April 2005; Accepted 4 May 2005; Published online 21 June 2005.

Abstract

An analysis of other primary cancers in individuals with non-Hodgkin's lymphoma (NHL) can help to elucidate this cancer aetiology. In all, 109 451 first primary NHL were included in a pooled analysis of 13 cancer registries. The observed numbers of second cancers were compared to the expected numbers derived from the age-, sex-, calendar period- and registry-specific incidence rates. We also calculated the standardised incidence ratios for NHL as a second primary after other cancers. There was a 47% (95% confidence interval 43–51%) overall increase in the risk of a primary cancer after NHL. A strongly significant (P<0.001) increase was observed for cancers of the lip, tongue, oropharynx^*, stomach, small intestine, colon^*, liver, nasal cavity^*, lung, soft tissues^*, skin melanoma^*, nonmelanoma skin^*, bladder^*, kidney^*, thyroid^*, Hodgkin's lymphoma^*, lymphoid leukaemia^* and myeloid leukaemia. Non-Hodgkin's lymphoma as a second primary was increased after cancers marked with an asterisk. Patterns of risk indicate a treatment effect for lung, bladder, stomach, Hodgkin's lymphoma and myeloid leukaemia. Common risk factors may be involved for cancers of the lung, bladder, nasal cavity and for soft tissues, such as pesticides. Bidirectional effects for several cancer sites of potential viral origin argue strongly for a role for immune suppression in NHL.