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Five Cancers Diagnosed at Later Stage in People With vs Without HIV
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CROI 2014, March 3-6, 2014, Boston
Mark Mascolini
Cervical cancer and four non-AIDS cancers-prostate, lung, breast, and melanoma-get diagnosed at a later stage in HIV-positive people than in the general population, according to results of a US cancer registry linkage analysis [1]. These cancers did not get diagnosed later in solid organ transplant recipients-who also have compromised immune function-than in the general population. Because of this difference, National Cancer Institute (NCI) researchers who conducted this study believe HIV-positive people get diagnosed later because of inadequate screening, not because immune suppression makes cancer progress faster in people with HIV.
In 2007 a meta-analysis of cancer incidence in people with HIV and organ transplant recipients determined that both groups had increased incidence of 20 of 28 cancers assessed compared with the general population [2]. These findings led the investigators to propose "that it is immune deficiency, rather than other risk factors for cancer, that is responsible for the increased risk" in these two immune-compromised groups.
Meredith Shiels and NCI colleagues conducted a different type of analysis focused on cancer stage at diagnosis and limited to US residents with HIV or a transplant. The investigators noted that, besides immune suppression, tumor aggressiveness and/or delayed screening may lead to later diagnosis. Transplant recipients share compromised immune function with HIV-positive people; but unlike many HIV-positive people in the United States, transplant recipients often have good access to healthcare. Shiels and collaborators proposed that diagnosis at a later stage in both populations could implicate immune suppression in cancer progression. But later cancer diagnosis only in people with HIV would tend to implicate poor healthcare utilization.
The NCI team analyzed 1996-2010 data on all cancer cases at 15 sites in two US linkage registries--the HIV/AIDS Cancer Match and the Transplant Cancer Match. The cancers analyzed were prostate, breast, lung, colorectal, bladder, melanoma, kidney, uterus, pancreas, thyroid, oral cavity, stomach, liver, anus, and cervix. The investigators calculated odds ratios (ORs) by cancer stage (local, regional, or distant) by separate logistic regression analyses comparing HIV populations and transplant populations with the general population. These analyses adjusted for age, sex, race, cancer registry, and calendar year.
The HIV registry analysis included 4.7 million cancer cases, 9362 of them in people with HIV. The solid organ transplant analysis involved 9.7 million cancer cases, 8225 of them in transplant recipients. The HIV analysis determined that, compared with the general population, HIV-positive people had independently higher odds of distant diagnosis of five cancers:
-- Breast: OR 1.90
-- Lung: OR 1.16
-- Prostate: OR 1.47
-- Cervical: OR 1.58
-- Melanoma: OR 2.42
But HIV-positive people had independently lower odds of late anal cancer diagnosis (OR 0.53). (The NCI team did not comment on this finding, but it may mean heightened awareness of anal cancer risk in people with HIV is resulting in earlier screening than in the general population.)
In contrast to the HIV registry findings, transplant recipients had independently lower odds of distant diagnosis of prostate cancer (OR 0.54) and lung cancer (OR 0.72) than the general population. Cancer stage at diagnosis did not differ significantly between transplant patients and the general population for cervical cancer, melanoma, or anal cancer.
Because of these contrasting findings, the NCI team proposed that "the increased stage observed in people with HIV is likely driven by delayed diagnosis due to under-utilization of care, particularly for screen-detectable cancers, and is unlikely to be due to immune suppression increasing cancer progression."
References
1. Shiels MS, Copeland G, Goodman M, et al. Cancer stage at diagnosis in HIV-infected individuals and transplant recipients. CROI 2014. Conference on Retroviruses and Opportunistic Infections. March 3-6, 2014. Boston. Abstract 705.
2. Grulich AE, van Leeuwen MT, Falster MO, Vajdic CM. Incidence of cancers in people with HIV/AIDS compared with immunosuppressed transplant recipients: a meta-analysis. Lancet. 2007;370:59-67.
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