Anal cancer survival rates lowest in black men

New research has identified significant racial and sex-based disparities in survival among patients with locoregional squamous cell carcinoma of the anus, especially in black men, who showed the lowest survival rates.

Squamous cell carcinoma of the anus (SCCA), the most common histologic subtype of anal cancer, is one of the few cancers whose incidence is rising in the U.S., with an especially rapid increase seen in black men. This new study reveals that known disparities in the incidence of this cancer appear to also extend to survival.

“SCCA has a very high cure rate with standard, nonsurgical treatments,” Muhammad Shaalan Beg, MBBS, of the division of hematology/medical oncology at the University of Texas Southwestern Medical Center in Dallas, said in a press release. “For a cancer that is so curable, even modest differences in the rate of treatment impact disease burden and overall survival. That is why we examined the differences in the rate of treatment for SCCA.”

Beg and colleagues identified 7,882 patients within the SEER database diagnosed with locoregional SCCA between 2000 and 2012 (median age, 58 years; 61.2% women; 86.3% white).

Median overall survival was 135 months, but this was lower among elderly patients (aged >65 years; 68 months), men (108 months), blacks (109 months) and in patients who were not treated with radiation therapy (121 months). Investigators noted that white women showed the longest OS (median, 148 months), followed by black women (146 months), white men (111 months) and black men (82 months). Hence, white women with SCCA survived 80% longer than black men with the same cancer.

A combination of chemotherapy and radiation therapy is the standard of care for locoregional SCCA. Overall, most patients (82.3%) were treated with radiation therapy, but black men showed the lowest rate of receiving radiation therapy (76.7%) while white women showed the highest (86.1%).

There are several possible causes for these disparities in patients receiving standard treatment, Beg and colleagues noted.

“Understanding health care disparities in SCCA is crucial as it largely affects at-risk and vulnerable populations, including ethnic minorities and those with HIV,” he said in the press release. “Indeed, through study of other cancer types, we have seen that non-white populations experience delays in diagnosis and treatment and are less likely to receive guidelines-adherent treatment.”

Finally, Beg and colleagues showed through multivariate analysis that age (HR = 1.19; 95% CI, 1.17-1.21 for each 5 additional years), male sex (HR = 1.59; 95% CI, 1.47-1.73), black race (HR = 1.51; 95% CI, 1.34-1.71 vs. white) and radiation therapy (HR = 0.9; 95% CI, 0.82-0.99) were all independently associated with OS.

“This report from a large cohort provides critical observations that reinforce two important concerns” Al B. Benson III, MD, of the Robert H. Lurie Comprehensive Cancer Center of Northwestern University, and chair of the NCCN Clinical Practice Guidelines in Oncology Panels for Colon, Rectal, and Anal Cancers, said in the press release. “First, the incidence of anal cancer is increasing secondary to rising numbers of individuals with HPV infection and the association with HIV infection.”

The press release noted that HIV-positive SCCA patients tend to be younger, male and black; that HIV-positive men who have sex with men have a higher risk than HIV-negative men for harboring SCCA-associated high-risk HPV; and that women with HPV are at higher risk for SCCA, but are more likely to receive radiation therapy and adhere to treatment than men.

“Second, health care disparities across diseases — including cancer — is a major problem in the United States, particularly for African American males,” Benson added. “As tragically noted from this SEER database assessment, it is also resulting in unacceptable outcomes. The authors provide insights as to the cause of disparities and methods to address the disparities with the hope that communities across the country will intervene to assist this vulnerable population.”

Beg and colleagues concluded that patient education and identifying high-risk individuals in primary care are essential for closing the gap in outcomes for patients with SCCA.

“It is critical that patients and physicians are aware that anal cancer can be cured in most patients,” Beg said. “Health systems should make every effort to increase health care delivery to at-risk groups who are often also socioeconomically challenged. We do not see such a striking racial and gender difference in survival in most other cancers.” – by Adam Leitenberger

Disclosures: One of the researchers (Meyer) reports he has received research support from Peregrine Pharmaceuticals and DFIN, Inc.