April 12, 2011 (Orlando, Florida) — The risk for stomach and esophageal cancer is higher among people with AIDS than among the general population, according to data presented here at the American Association for Cancer Research (AACR) 102nd Annual Meeting.
For stomach carcinomas, the overall risk was 70% higher among people with AIDS and the risk for stomach lymphomas was 36-fold higher.
People with AIDS also face an overall risk for esophageal malignancies that is 2.7 times higher than in the general population. When broken down by subtype, the risk was 54% higher for squamous cell carcinomas, 101% higher for adenocarcinomas, and 261-fold higher for lymphomas of the esophagus.
"This study was quite fascinating," said AACR president-elect Judy Garber, MD. "As far as I'm aware, most AIDS malignancies are lymphomas. This is quite remarkable to show solid tumor differences, but also worrisome."
Dr. Garber is director of the center for cancer genetics and prevention at the Dana-Farber Cancer Institute in Boston, Massachusetts, and was not involved in the study.
Clinicians should certainly be aware that there might be a risk for solid tumors, she told Medscape Medical News, but at this time, routine screening for these malignancies is not recommended.
However, it is something that clinicians should keep in mind when a patient becomes symptomatic. "Instead of thinking that everything that happens to HIV patients must be infection, this is something else to consider," she said, "although infection may have to do with the underlying mechanism seen here."
"These data suggest that we now have to look at AIDS survivors, who are becoming a very large and growing population, and who are now showing a risk for another group of diseases," Dr. Garber added.
Are They at Higher Risk?
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| Dr. Christina Persson |
It is well established that HIV-infected individuals have an increased risk for malignancy, especially when the cancer is related to infection. During a press briefing that highlighted the results of the study ahead of the presentation, lead author E. Christina Persson, PhD, noted that although Helicobacter pylori infection is associated with stomach cancer, it is also thought to be protective against esophageal cancer.
Previous studies have also shown that H pylori is related only to stomach cancers of the noncardia, not the cardia, anatomic site. Dr. Persson, a postdoctoral fellow at the National Cancer Institute, Bethesda, Maryland, and colleagues asked whether "people with HIV/AIDS are at a higher risk of esophageal and gastric cancers, and whether this varies by histologic subtype and anatomic subtype."
They hypothesized that in the HIV/AIDS population, rates of noncardia stomach cancers would higher than rates of cardia stomach cancers, and they compared the risk for esophageal and stomach cancer between people with AIDS and people in the general population.
Risk Driven By Lymphomas
The authors used data from the HIV/AIDS Cancer Match Study, which is a linkage of 15 American population-based HIV/AIDS and cancer registries that includes data from 1980 through 2007. The cohort consisted of 597,073 people with AIDS, 1,166 of whom developed stomach malignancies and 240 of whom developed esophageal malignancies. The database covers the entire AIDS era, Dr. Persson noted.
Standardized incidence ratios (SIRs) were used to compare the risk for stomach and esophageal cancer by histologic and anatomic sites between AIDS patients and the public at large. The authors also evaluated associations with immune suppression by testing for trends in SIRs across several time periods (60 months before AIDS diagnosis until 120 months after diagnosis) with Poisson regression.
At both sites, the bulk of increased risk for AIDS patients was driven by excess lymphomas. The overall SIR for stomach nonmucosa-associated lymphoid tissue lymphomas (40; 95% confidence interval [CI], 37 to 43) was almost 8 times higher than for mucosa-associated lymphoid tissue lymphomas (5.5; 95% CI, 3.5 to 8.2).
The increased risk for lymphoma was expected among AIDS patients, Dr. Persson explained, but the increased risk for carcinomas was unexpected. The size of the cohort also allowed the authors to evaluate carcinoma subtypes.
Compared with the general population, the risk for stomach adenocarcinoma in AIDS patients was elevated in the noncardia region of the stomach (SIR, 1.6; 95% CI, 1.2 to 1.9), but not in the cardia region (SIR, 1.1; 95% CI, 0.8 to 1.6).
When assessing subtypes in esophageal cancer, increased SIRs were observed for squamous cell carcinoma (1.5; 95% CI, 1.2 to 1.8), adenocarcinoma (1.7; 95% CI, 1.3 to 2.2), and lymphoma (123; 95% CI, 94 to 158). In addition, an increased risk was seen for squamous cell carcinoma of the abdominal/lower esophagus (SIR, 1.7; 95% CI, 1.1 to 2.5).
The authors have disclosed no relevant financial relationships.
American Association for Cancer Research (AACR) 102nd Annual Meeting: Abstract 3744. Presented April 4, 2011.
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