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CANCER STAGE, TREATMENT, AND SURVIVAL COMPARING HIV CLINIC ENROLLEES AND SEER
Keri Calkins1, Geetanjali Chander1, Corinne Joshu1, Anthony T. Fojo1, Richard D. Moore1, Bryan Lau1
1The Johns Hopkins University, Baltimore, MD, USA
The effect of HIV on cancer stage, treatment, and survival is unclear and differences may be driven by immune suppression and/or access to care. We compared cancer outcomes among people with HIV (PWH) enrolled in care to the general US population, with a sub-analysis stratified by CD4 count.
We compared cancer stage at diagnosis, receipt of any cancer treatment, and restricted mean survival time (RMST) between 255 cancer cases in PWH enrolled in the Johns Hopkins HIV Clinical Cohort (JHHCC) and similar cases sampled from the NCI's Surveillance, Epidemiology and End Results Program (SEER), presumed to be largely HIV negative. We performed G-computation using random forest methods to estimate the effect of HIV on stage and treatment risk differences (RD) and on RMST differences, adjusting for demographic and cancer covariates. We also stratified the JHHCC by CD4 cell count ≤200 and >200 cells/mm[sup]3[/sup], to examine effect modification by immune status at cancer diagnosis.
The probability of localized cancer was 0.30 among PWH in JHHCC, while it was 0.07 in SEER (Risk difference (RD)= 0.24 [95% CI= 0.17, 0.31]). Similarly, the probability of distant cancer was 0.45 in JHHCC versus 0.07 in SEER (RD=0.38 [95% CI= 0.31, 0.43]). Among those in JHHCC with ≤CD4 200, 74% received any cancer treatment compared to 80% of SEER (RD=-0.06 [95% CI= -0.24, -0.02]), but there was no difference in cancer treatment overall or at higher CD4 levels. Table 1 provides a comparison of mortality after cancer diagnosis between JHHCC and SEER. Model 1 accounted for age, sex, race, year of diagnosis, and cancer type; while model 2 also adds CD4 count at cancer diagnosis. PWH had evidence of reduced survival of all cancers after adjusting for the model 1 covariates (RMST Difference= -3.4 months [95% CI= -7.1, -0.2]). The observed difference was larger when examining PWH with CD4 ≤200 adjusting for the model 2 covariates (-10.6 months [95% CI=-18.3, -4.9]). Differences in survival were no longer significant when stage and treatment were added to the models.
PWH are more likely to be diagnosed with cancer at earlier and later stages than the general US population, suggesting that HIV may contribute to faster progression and that engagement in HIV care may improve earlier detection. Survival differences were largely explained by cancer stage and treatment, although there is some evidence of lower rates of cancer treatment and higher mortality in those with low CD4 counts.