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Anal cancer diagnosed earlier in HIV+ men,
but cancer-specific survival similar to HIV- men
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CROI 2015, February 23-26, 2015, Seattle, Washington
Mark Mascolini
HIV-positive men with squamous cell carcinoma of the anus (SCCA) got diagnosed at earlier stages than HIV-negative men in a 1997-2009 US analysis [1]. Treatment patterns differed by HIV status, but in adjusted analysis SCCA-specific survival did not differ between the two groups.
Researchers from New York's Mount Sinai School of Medicine noted that SCCA is a rare cancer, but its incidence has been rising by about 2% yearly in the United States in both men and women [2,3]. People with HIV account for some of these new diagnoses, with SCCA now the second most common non-AIDS cancer in HIV populations [4]. The Mount Sinai team observed that chemoradiotherapy with 5-fluorouracil and mitomycin C is the standard treatment for early-stage SCCA. Research before the antiretroviral era found worse outcomes in HIV-positive than negative people with invasive SCCA, including increased toxicity, decreased tolerability, more treatment interruptions, and declining immune function.
To get a better understanding of SCCA diagnosis, treatment, and survival in US men with and without HIV in more recent years, these investigators turned to the Surveillance, Epidemiology, and End Results (SEER) registry linked to Medicare claims. They identified four outcomes of interest: (1) all-cause mortality, (2) anal cancer-specific mortality, (3) anal cancer recurrence, and (4) colostomy placement. To compare outcomes in men with and without HIV, they used Cox regression models adjusted for age, race/ethnicity, modified Charlson comorbidity score, initial course of treatment, and year of SCCA diagnosis.
The Mount Sinai investigators created two study groups, one with stage I/II cancer and one with stage III/IV. The stage I/II group included 312 men with HIV and 539 without HIV. Average age at SCCA diagnosis was significantly younger in the HIV group (48 versus 70, P < 0.05), and the HIV group included a significantly lower proportion of Caucasians and significantly higher proportions of blacks and Hispanics. Charlson comorbidity score was significantly better in the HIV group (P < 0.05). A growing proportion of HIV-positive men got diagnosed in each later period: 19% in 1997-2001, 35% in 2002-2005, and 46% in 2006-2009. Respective proportions in the HIV-negative group were 24%, 39%, and 37% (P < 0.05).
The stage III/IV group included 47 men with HIV and 93 without HIV. Average age at SCCA diagnosis was again significantly lower in the HIV group (47 versus 67, P < 0.05). Higher proportions of HIV-positive men were black or Hispanic, but the difference from the HIV-negative group lacked statistical significance (P = 0.12). Men with HIV had lower comorbidity scores than men without HIV, but the difference was not statistically significant. Year of diagnosis did not differ significantly between the two groups.
SCCA treatment did not vary by HIV status in men diagnosed with stage III/IV cancer. But HIV status did affect treatment choice for men diagnosed with stage I/II cancer. A higher proportion of men with HIV had surgery, chemotherapy, and radiation (30% versus 23%), while lower proportions of men with HIV had radiation only (9% versus 15%) or chemotherapy plus radiation (21% versus 30%) (P = 0.001).
Adjusted analysis determined that men with HIV had worse overall survival than HIV-negative men (adjusted hazard ratio [aHR] 1.5, 95% confidence interval [CI] 1.2 to 2.0). But in the adjusted analysis men with HIV did not differ from the control group in SCCA-specific survival (aHR 0.83, 95% CI 0.51 to 1.37), colostomy placement, or cancer recurrence. Median overall survival in HIV-positive men ranged from 95 months (95% CI 79 to 125) for those with stage I cancer to 23 months (95% CI 10 to 56) for those with stage IV.
The researchers suggested that earlier SCCA stage at diagnosis in men with HIV could reflect more intense anal cancer screening in HIV-positive men. The nonsignificant difference in SCCA survival between the two groups, the Mount Sinai team proposed, suggests that overall survival differences reflected HIV-related causes of death.
References
1. Pitts RA Goldstone S, Sigel K, Gaisa MM, Sigel C, Wisnivesky J. Survival and treatment trends for squamous cell carcinoma of the anus in HIV infection. CROI 2015. February 23-26, 2015. Seattle, Washington. Abstract 715.
2. Grulich AE, Poynten IM, Machalek DA, Jin F, Templeton DJ, Hillman RJ. The epidemiology of anal cancer. Sex Health. 2012;9:504-508.
3. Johnson LG, Madeleine MM, Newcomer LM, Schwartz SM, Daling JR. Anal cancer incidence and survival: the surveillance, epidemiology, and end results experience, 1973-2000. Cancer. 2004;101:281-288.
4. Munoz-Bongrand N, Poghosyan T, Zohar S, et al. Anal carcinoma in HIV-infected patients in the era of antiretroviral therapy: a comparative study. Dis Colon Rectum. 2011;54:729-735.
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