Researchers from France have reported that persons with schizophrenia have an increased risk of mortality from cancer, especially from breast cancer for women and lung cancer for men. The details of this study appeared in the August, 2009 issue of Cancer.[1] 

The relationship between cancer incidence and schizophrenia is controversial. There have been claims that patients with schizophrenia have a lower incidence of cancer than the general population. However, most of these studies have been deemed flawed—except for the lower incidence of skin cancer, which may be related to lack of sun exposure. One reliable study published in the British Journal of Psychiatry that involved almost 10,000 persons with schizophrenia found an identical risk of overall cancer compared to a control population.[2] However, they did find an increased risk of cancer of the esophagus (RR 1.61) and a decreased risk of skin cancer (RR 0.56) among schizophrenics. There was also a slight increased risk for lung cancer, which was not statistically significant (RR 1.18).

Researchers involved in the current study sought to determine if deaths related to cancer contributed to the known increased premature deaths in persons with schizophrenia. This was a prospective study started in 1993 that involved 3,470 persons with schizophrenia. The mortality rate during this 11-year follow-up was 14%, which was a fourfold increase compared with the general population. They found that cancer was the second most common cause of death with a standard mortality ratio (SMR) of 1.4. For all cancers the SMR was 1.4 in men and 1.9 in women. Lung cancer was the most common location with an SMR of 2.2. Breast cancer was the most common location in women with a AMR of 2.8. Lung cancer deaths were attributed to smoking, which is common among schizophrenics. Breast cancer deaths were attributed to delayed diagnosis.

Comments: This study suggests that cancer mortality is increased in male schizophrenics from smoking and that women with breast cancer may be diagnosed at later stages, resulting in increased mortality. This study did not discuss incidence, but there did not appear to be more cancers in schizophrenics than in the general population with similar risk factors.