Higher mortality in elderly HIV-positive people with prostate, breast or colorectal cancer

Outcomes for some common cancers are significantly poorer among people with HIV over the age of 65 compared to HIV-negative people of the same age, according to research published in JAMA Oncology. The study is especially important because all the patients received appropriate therapy for their cancer soon after it was diagnosed. People with HIV had an increased risk of cancer relapse and death.

The investigators suggest that the higher mortality risk observed in people with HIV is likely due to immune suppression, and believe their findings are especially significant given the ageing of the HIV-positive population.

“Elderly HIV-infected patients with cancer experience poorer cancer outcomes than HIV-uninfected patients receiving similar stage-appropriate treatment,” comment the researchers. “People living with HIV are expected to die at higher overall rates due to the contribution of AIDS-related comorbidities, but we report that HIV-infected patients with cancer who are 65 years and older are also at increased risk of cancer-specific death and relapse after initial therapy.”

Glossary

relapse

The return of signs and symptoms of a disease after a patient has been free of those signs and symptoms. 

epidemiology

The study of the causes of a disease, its distribution within a population, and measures for control and prevention. Epidemiology focuses on groups rather than individuals.

neoplasm

An abnormal and uncontrolled growth of tissue; a tumour.

malignant

Describes tumours which grow rapidly, infiltrate surrounding tissues and spread around the body. 

lymph nodes

Bean-sized structures throughout the body's lymphatic system, where immune cells congregate to fight infections. Clusters of lymph nodes are found in the underarms, the groin, and the neck.

Improvements in treatment and care mean that many people with HIV now have an excellent chance of surviving well into old age. The diseases of ageing – including common cancers such as those of the breast and prostate – are an increasingly important cause of serious illness and death among people with HIV.

Some research suggests that people with HIV have poorer survival after cancer diagnosis when compared to than HIV-negative individuals with the same cancer. A team of investigators in the United States, led by Dr Anna Coghill of the National Cancer Institute, hypothesised that this was because people with HIV were less likely to promptly receive the right cancer treatment and care.

They therefore designed a study using nationally representative epidemiological data comparing mortality and relapse risk between elderly HIV-positive and HIV-negative patients, all of whom received treatment that was appropriate for the clinical stage of their cancer in the year after initial cancer diagnosis.

The patients were aged 65 and older and received care between 1996 (the year triple HIV therapy first became available) and 2012.

Cancers covered by the study were colorectal (bowel), prostate, breast and lung. While rates of the first three cancers are no higher in people with HIV than in the general population, they are very common cancers across the population, including amongst people living with HIV.

Outcomes were overall mortality, cancer-related mortality and cancer relapse/mortality. Findings were adjusted to take account of other variables that affect outcomes including age, race, cancer stage, year of cancer diagnosis (before or after 2004) and income.

All the patients were enrolled in the Surveillance, Epidemiological and End-Results (SEER) database of Medicare recipients. The study population consisted of approximately 308,000 HIV-negative patients and 288 HIV-positive individuals.

People with HIV were younger than the HIV-negative individuals (47 vs 29% aged 65 to 69) and more likely to be non-white (37 vs 8%). Prostate cancer represented over half (59%) the cancers diagnosed in HIV-positive people compared to 43% of those diagnosed in HIV-negative participants. But the investigators emphasise that this disparity was because the HIV-positive study participants were more likely to be male (78 vs 55%).

Comparison of overall mortality rates, starting one year after cancer diagnosis, showed that these were significantly higher for HIV-positive compared to HIV-negative people for colorectal cancer (HR = 1.73; 95% CI, 1.11-2.68, p = 0.02), prostate cancer (HR = 1.58; 95% CI, 1.23-2.03, p < 0.01) and breast cancer (HR = 1.50; 95% CI, 1.01-2.24, p = 0.05).

Cancer-specific mortality was also elevated – but not significantly – among HIV-positive compared to HIV-negative people for breast cancer (HR = 1.85; 95% CI, 0.96-3.55, p = 0.07) and prostate cancer (HR = 1.65; 95% CI, 0.98-2.79, p = 0.06).

Further analysis, however, indicated cancer-specific mortality was significantly higher for HIV-positive women diagnosed with regional-stage breast cancer (i.e. cancer that had spread outside the breast to nearby structures or lymph nodes) (HR = 2.91; 95% CI, 1.31-6.46, p < 0.01).

Next the investigators examined the combined outcome of cancer relapse or cancer-specific death. When compared with HIV-negative men with prostate cancer, those with HIV had an increased risk that was not statistically significant (HR = 1.28; 95% CI, 0.92-1.78). When compared with HIV-negative women with breast cancer, those with HIV had a significantly increased risk (HR = 1.90; 95% CI, 1.10-3.28).

The associations seen between HIV and increased overall and cancer-related mortality were not observed for three other illnesses common in older age: gastro-oesophageal reflux, hypertension and migraines.

“Our observation of a persistent survival disparity after adjusting for available first-year cancer treatment data suggests that health care differences are not the sole driver of poor cancer outcomes in the HIV population,” say the authors. They suggest that these differences are more likely to be a direct result of immune suppression. They emphasise that outcomes were poorer in HIV-positive patients for cancers with a range of causes, suggesting that HIV-related immune suppression has an important role in response to cancers.

“HIV was associated with an elevated risk of overall and cancer-specific mortality. HIV patients with prostate and breast cancer appeared to be at particularly increased risk of worse outcomes, even after adjusting for available data on first-year cancer treatment,” conclude the authors.

“As the HIV population continues to age, the association of HIV infection with poor breast and prostate cancer outcomes will become increasingly relevant, especially because prostate cancer is projected to become the most common malignant neoplasm in the HIV population in the United States by 2030. Research on clinical strategies to improve outcomes in HIV-infected patients with cancer is warranted.”

References

Coghill AE et al. HIV infection, cancer treatment regimens, and cancer outcomes among elderly adults in the United States. JAMA Oncology, 2019. doi: 10.1001/jamaoncol.2019.1742

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