Black men with prostate cancer may respond better to radiation therapy than white men

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Researchers at the UCLA Jonsson Comprehensive Cancer Center, who led a meta-analysis of seven randomized trials, found an “unexpected result”: although black men appeared to have a more aggressive disease than they did in clinical trials of radiation therapy for prostate cancer, their treatment outcomes were and Disease-specific results were better than those of their white counterparts.

These results provide high-level evidence that challenges the popular belief that black men diagnosed with prostate cancer inevitably have a worse prognosis than white men. “

Dr. Amar Kishan, Associate Professor and Vice Chairman, 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-senior author of an article in the December 29th issue of JAMA network open.

“This is especially important because an ill-founded belief can inadvertently contribute to ‘cancer injustice,’ ‘leading to more aggressive treatments than might be needed – potentially affecting the quality of life – and distracting attention from other important factors affecting one Can impact outcome, including access to more comprehensive health care, “said Kishan, director of the genitourinary oncology service for the Radiation Oncology Department at the David Geffen School of Medicine at UCLA and at the 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’s Jonsson Comprehensive Cancer Center, said black men are more likely to be diagnosed with prostate cancer than white men, and they have a two-fold increase Risk of dying from the disease, but to date there have been no significant studies to assess racial differences in responses to initial therapy.

“Although previous studies have shown death from prostate cancer to be similar in black men and white men – provided there is equal access to medical care and standardized treatments – prostate cancer death is often the culmination of many years of rescue therapies, and the Prostate cancer mortality does not intrinsically represent the initial response to primary therapy. Here we examined early metrics of response to treatment, including biochemical recurrence (PSA rise above a threshold) or development of distant metastases in men with localized prostate cancer, including those with predominant Disease state. This information will help us identify potential causes and mitigations of differences in the treatment of prostate cancer, “said Ma, co-first author of Tahmineh Romero, chief statistician in the UCLA Department of Medicine Statistics Core.

Co-senior author Dr. Daniel Spratt, Chair of the Department of Radiation Oncology at the University Hospitals Seidman Cancer Center, said, “Race is a social construct and therefore all observed outcomes must be viewed through this lens; this includes the social and / or biological manifestations of structural racism.”

Ma added that it was important to note that the men in these trials not only had access to clinical trials, but also participated in trials where all patients received the same treatment. Because black men tend to be less willing to participate in clinical trials – a by-product of medical distrust – this equity in access to health care and treatment may not be representative of the general population.

In addition, most deaths that occur in both black and white men are due to causes other than prostate cancer. “This underscores the importance of universal health care, which can affect survival outcomes at the population level,” said Kishan.

In what is arguably the largest meta-analysis of its kind on the subject, the researchers reviewed individual patient data from 8,814 patients from seven randomized clinical trials of radiation therapy for prostate cancer – studies involving significant numbers of black men and were conducted by the Radiation Therapy Oncology Group (RTOG) / NRG Oncology performed. All patients in the studies received either standard or high-dose radiation therapy, and some patients also received short- or long-term androgen deprivation therapy.

Of the total of 1,630 men identified themselves as black; 7.184 as white. Overall, black men were younger, with a mean age of 68 versus 71, and they were significantly more likely to have high-risk disease. To examine the relationship between race and treatment efficacy, researchers extracted and analyzed statistics on relapse (biochemical relapse, or BCR), metastasis (distant metastasis, or DM), and prostate cancer-specific mortality, or PCSM, and other secondary endpoints.

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

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

Source:

University of California – Los Angeles Health Sciences

Journal reference:

Ma, 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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