(RxWiki News) Lupus is a disease that can affect almost any area of the body, and a new review showed that the condition might also carry a greater risk for certain other diseases.
The researchers examined a variety of different studies involving lupus patients and cancer rates.
"See your doctor if you're experiencing persistent joint pain."
According to the authors of this review, a link between lupus and cancer has been the subject of much research with wide findings. These researchers, led by J. Ni, of the School of Public Health at Anhui Medical University in Hefei, China, aimed to review studies on this topic.
To do so, they searched for studies that looked at cancer incidence in patients with systemic lupus erythematosus (SLE), often referred to simply as lupus.
According to the American College of Rheumatology (ACR), lupus is a chronic disease characterized by inflammation that can affect a number of parts of the body, including the skin, joints, lungs and kidneys.
"Most patients feel fatigue and have rashes, arthritis (painful and swollen joints) and fever," explained ACR.
Ni and colleagues looked at both overall rates of malignancy, or the presence of cancerous cells that might spread, and the rates of malignancy in four specific parts of the body — lung, liver, prostate and bladder cancer.
Overall, seven studies were examined. Six looked at overall malignancy, seven looked at lung cancer, five looked at liver cancer, four at prostate cancer and six at bladder cancer.
The individual studies had populations ranging from 860 participants to 30,478 participants and average follow-up times ranging from 5.18 years to 16.5 years. These studies were started as early as 1958 and ended as late as 2009.
The information was used to determine standardized incidence rates (SIRs) of cancer in lupus patients, a measure which shows if the number of cancer cases seen are higher or lower than expected. An SIR of 1 would represent the expected rate in a normal population; an SIR above 1 represents greater rates than normal or than would be expected; and an SIR below 1 represents fewer cancer cases than expected.
Ni and colleagues found that overall malignancy, lung and liver cancers were seen most frequently in lupus patients. Lupus patients had an SIR for overall malignancy of 1.16, an SIR for lung cancer of 1.68 and an SIR for liver cancer of 2.44 — noticeably higher than expected.
Despite these findings, the researchers also uncovered some positive news for lupus patients. They saw evidence that the risk of prostate cancer was somewhat reduced in male lupus patients — the SIR for prostate cancer in this group was 0.71.
"This meta-analysis shows that SLE patients are at increased risk of developing cancer, particularly of the lung, bladder and liver. However, males with SLE have a decreased risk of prostate cancer," Ni and colleagues concluded.
This review did not explore why an increased risk might exist, but the review's authors suggested that it might be related to the immune system, as lupus is an autoimmune condition caused by an incorrect immune response, or related to certain medications used to treat some forms of lupus.
"Lupus is a complex disease. As experts in diagnosing and treating autoimmune diseases such as lupus, rheumatologists can best advise patients about treatment options," suggested ACR.
"Causes for cancer are very complex and unlikely to be related to any one underlying cause, and the association with lupus is even less understood," said Bibas Reddy, DO, a member of the medical staff of Baylor All Saints Medical Center at Fort Worth.
"The findings of this meta-analysis report of prior studies definitely provides groundwork for further research with prospective, case controlled studies to assess the potential link between lupus patients and their risks for developing cancer. In the interim, stressing cancer prevention, for example tobacco cessation, along with appropriate screening for colon, breast, and prostate cancers should be discussed with lupus patients," said Dr. Reddy, who was not involved in this study.
This review was published January 15 in the journal Lupus. No conflicts of interest were reported.