Black men with prostate cancer may have a better response to radiation therapy than white men

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UCLA Jonsson Comprehensive Cancer Center researchers leading a meta-analysis of seven randomized trials found an “unexpected result”: although black men appeared to have more aggressive disease when they enrolled in clinics. Radiation therapy clinical trials for prostate cancer, their treatment outcomes and disease – specific results were better than their white counterparts.

These findings provide high-level evidence challenging the common belief that black men who are diagnosed with prostate cancer will necessarily have a worse prognosis than white men.. “

Dr Amar Kishan, Associate Professor and Vice President of Clinical and Translational Research, Department of Radiation Oncology, University of California, Los Angeles

Kishan is also a researcher at UCLA Jonsson Comprehensive Cancer Center. Kishan is the co-lead author of an article in the Dec. 29 issue of JAMA network open.

“This is especially important because an unfounded belief can inadvertently contribute to ‘cancer injustice’, leading to the use of more aggressive treatments than necessary; potentially reducing the quality of life; and distracting attention from other important factors that may influence outcome, including access to more comprehensive health care, ”said Kishan, head of genitourinary oncology in the radiation oncology department of the David Geffen School of Medicine at UCLA and UCLA Jonsson Comprehensive Cancer Center.

Dr. Ting Martin Ma, a resident physician in the Department of Radiation Oncology at UCLA’s David Geffen School of Medicine and a researcher at UCLA Jonsson Comprehensive Cancer Center, said black men are more likely to be diagnosed with cancer. prostate than white men. , and they have a double the risk of dying from the disease, but so far there have been no significant studies to assess breed-specific differences in response to initial treatment.

“Although previous studies have shown prostate cancer deaths to be similar for black men and white men, provided there is equal access to standardized care and treatment, cancer deaths cancer are often the culmination of many years of multiple lifesaving therapies, and prostate cancer mortality does not inherently capture the initial reactivity to primary treatment. Here we have investigated the first parameters of response to treatment, including including biochemical recurrence (increase in PSA above a threshold) or the development of distant metastases in men with localized prostate cancer, which is also the Patients with a predominant disease state present. information will help us identify potential factors and mitigating factors of disparities in prostate cancer care, ”said Ma, co-pr first author with Tahmineh Romero, senior statistician in the Department of Statistical Medicine at UCLA.

Co-lead author Dr Daniel Spratt, chairman of the Seidman Cancer Center Radiation Oncology Department at University Hospitals, said: “Race is a social construct, and therefore any findings observed should be viewed through this lens. ; this includes social aspects and / or biological manifestations of structural racism. “

Ma added that it’s important to note that the men in these studies not only got access to clinical trials, but also signed up for trials where all patients received the same treatment. Because black men tend to be less willing to consider participating in clinical trials – a byproduct of medical mistrust – this equity in accessing care and receiving treatment may not be representative of the population. general.

Additionally, most deaths that occur in black and white men are due to non-prostate cancer causes. “This underscores the importance of health care in general, which can influence survival outcomes at the population level,” Kishan said.

In what is considered the largest meta-analysis of its kind on the subject, researchers looked at individual data from 8,814 patients from seven randomized clinical trials of radiation therapy for prostate cancer; studies that recruited a substantial number of black men and were conducted by the Radiation Therapy Oncology Group (RTOG) / NRG Oncology. All of the patients in the trials received standard or high-dose radiation therapy, and some patients also underwent short- or long-term androgen deprivation therapy.

Of the total, 1,630 men identified themselves as black; 7,184 in white. Overall, black men were younger, with a median age of 68 versus 71, and they were significantly more likely to have a high-risk disease. To study associations between race and treatment effectiveness, the researchers extracted and analyzed statistics on recurrence (biochemical recurrence, or BCR), metastasis (distant metastasis, or MD), and cancer-specific mortality. prostate, or PCSM, and other secondary endpoints.

According to the results, black men were significantly younger and more likely to have high-risk disease at the time of treatment, but they had lower rates of recurrence, metastasis, and PCSM than white men, even without adjustment. statistical. When adjustments were made for age and other factors, “race remained significantly associated with improved BCR, DM, and PCSM outcomes,” the authors reported in the article. “The fact that black men improved both early and late disease outcomes compared to white men is a new and unexpected finding that demonstrates that black men may have a better response to their initial treatment.”

“These results do not suggest that there are no biological differences that could lead to differences in the incidence of prostate cancer between racial groups,” the authors said. “In fact, it is possible that the association with the differential response to treatment that is noted is, at least in part, explained by differences in the underlying biology.”

Source:

Journal reference:

Mom, MT, et al. (2021) Comparison of the response to definitive radiation therapy for localized prostate cancer in black and white men A meta-analysis. JAMA network open. doi.org/10.1001/jamanetworkopen.2021.39769.


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