Over the past 30 years, squamous cell carcinoma of the anus (SCCA) is one of the few cancers with steadily rising incidence in the United States, with the most rapid increase seen in black men. To further investigate this trend, researchers at the University of Texas Southwestern Medical Center looked at more than 7,800 cases of SCCA in the United States and found that the complex chemistry of social, economic, biologic, and cultural factors led not only to disparities in incidence, but also survival.
Their findings, "Racial and Gender Disparities in the Therapy and Outcomes of Squamous Cell Carcinoma of the Anus", are published in the August 2017 issue of JNCCN – Journal of the National Comprehensive Cancer Network.
"SCCA has a very high cure rate with standard, nonsurgical treatments. 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," explained Muhammad Shaalan Beg, MD, who led the team of researchers.
Using SEER data from 2000 – 2012, Beg et al studied a cohort of more than 7,800 patients, average age 58, and found that white women diagnosed with locoregional SCCA lived 80% longer than black men with the same disease. Overall survival for white women was 148 months, followed by black women at 146 months, white men at 111 months, and black men at 82 months.
Receiving standard of care
The standard of care for locoregional SCCA is a combination of chemotherapy and radiation therapy, with second- and third-line therapy reserved for those with residual or recurrent disease. However, after examining the SEER data, Dr. Beg and colleagues noted that black patients had a lower rate of radiation therapy. According to the researchers, there are several possible causes for this lack of receipt of standard therapy.
"Understanding health care disparities in SCCA is crucial as it largely affects at-risk and vulnerable populations, including ethnic minorities and those with HIV. 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," said Beg.
The same socioeconomic and behavioral factors that inhibit access to standard therapy probably also negatively influence prevention of disease- as well as time of detection, diagnosis, treatment, and post-treatment quality of life- all factors that directly correlate to overall survivorship.
Moreover, patients with low socioeconomic status tend to have lower health literacy, lack of health insurance, and geographical barriers to high-quality care, the researchers noted.
Correlation between HIV/HPV status and SCCA
SCCA largely affects at-risk populations, which include ethnic minorities and those with HIV. HIV-positive individuals with SCCA tend to be younger, male, and black. Moreover, previous studies show that HIV-positive men who have sex with men are at higher risk of harboring high-risk HPV than HIV-negative men. High-risk HPV is known to be associated with anal dysplasia and SCCA.
While women with HPV are at higher risk, the authors note that women are also more likely to receive radiation and to adhere to therapy than men.
"This report from a large cohort provides critical observations that reinforce two important concerns. First, the incidence of anal cancer is increasing secondary to rising numbers of individuals with HPV infection and the association with HIV infection. Second, health care disparities across diseases- including cancer- is a major problem in the United States, particularly for African American males. As tragically noted from this SEER database assessment, it is also resulting in unacceptable outcomes," said Al B. Benson III, MD, Robert H. Lurie Comprehensive Cancer Center of Northwestern University, Chair of the NCCN Clinical Practice Guidelines in Oncology (NCCN Guidelines®) Panels for Colon, Rectal, and Anal Cancers. "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."
Closing the gap
According to the authors, primary care physicians should be encouraged to identify high-risk individuals to enable targeted screening efforts. Together with patient education on the importance of self-management of comorbid conditions, lifestyle modifications, and identification of and following up on existing non-malignant anogenital warts, caretakers across the continuum of care can begin to put in place strategies for improving the outcome for all patients with SCCA.
According to Dr. Beg, "It is critical that patients and physicians are aware that anal cancer can be cured in most patients. 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."