In terms of possible mechanisms underlying the increased risk of breast cancer seen in this study, the authors suggested that people with schizophrenia could experience other clinical conditions such as obesity that might increase their risk of breast cancer.
“As breast cancer may be a hormone-dependent cancer, a significant positive association between plasma prolactin levels and the risk of breast cancer has been observed; in addition, increased prolactin levels have been documented in women with schizophrenia, particularly for those receiving certain antipsychotics,” they wrote.
While the incidence of cancer in people with schizophrenia might not necessarily differ from that of the general population, the authors said studies have found that people with schizophrenia have higher cancer mortality. Because “breast cancer prevention and treatment options are less optimal in women with schizophrenia, our results highlight that women with schizophrenia deserve focused care for breast cancer screening and treatment,” they wrote.
The Tianjin Health Bureau Foundation and the Natural Science Foundation of Tianjin, China, supported the study. No conflicts of interest were declared.
SOURCE: Zhuo C et al. JAMA Psychiatry. 2018 Mar 7. doi: 10.1001/jamapsychiatry.2017.4748.