Assessing Disparities in Receipt of Shorter Radiation Regimens and Treatment Noncompletion in Prostate Cancer, Journal Club - Zachary Klaassen
February 7, 2023
In this UroToday Journal Club, Zachary Klaassen discusses the publication titled Shorter Radiation Regimens and Treatment Non-Completion Among Patients with Breast and Prostate Cancer in the United States: An Analysis of Racial Disparities in Access and Quality. The goal of this analysis is to assess trends in the uptake of shorter radiation regimes with a focus on the data for prostate cancer and breast cancer and assess rates of treatment non-completion. The hypothesis of this study is that Black patients may have higher rates of non-completion overall, though this would be eliminated with the use of shorter hypofractionated radiation regimes. In addition, the authors sought to determine if black patients would be less likely to receive hypofractionated regimes despite these potential clinical benefits. Drs. Wallis and Klaassen talk through this publication and its results.
Biographies:
Zachary Klaassen, MD, MSc, Urologic Oncologist, Assistant Professor Surgery/Urology at the Medical College of Georgia at Augusta University, Georgia Cancer Center
Biographies:
Zachary Klaassen, MD, MSc, Urologic Oncologist, Assistant Professor Surgery/Urology at the Medical College of Georgia at Augusta University, Georgia Cancer Center
Read the Full Video Transcript
Chris Wallis: Hello, and thank you for joining us for UroToday Journal Club discussion. Today we're talking about a paper entitled Shorter Radiation Regimens and Treatment Non-Completion Among Patients with Breast and Prostate Cancer in the United States: An Analysis of Racial Disparities in Access and Quality. I'm Chris Wallis an Assistant Professor in the division of Urology at the University of Toronto. With me today is Zach Klaassen, an Assistant Professor in the Division of Urology at the Medical College of Georgia.
You can see here the citation for this recent publication, by way of background, breast and prostate cancer account for together more than 40% of all cancers that are treated with radiotherapy in the United States. Historically, for both of these conditions, radiotherapy has been administered with conventional fractionation, which comprises more than 40 treatments for patients with prostate cancer and more than 20 treatments for those with breast cancer.
However, recently hypofractionation has been shown to have comparable oncologic efficacy in both disease states. Hypofractionation offers a number of potential benefits to patients as well as to the healthcare system in terms of both cost and convenience. An important benefit of hypofractionation is improved treatment completion because with fewer treatments to administer and fewer to be received by the patient it is more likely that patients will receive all their therapy. Thus, overall adoption of hypofractionation may actually improve the quality of radiotherapy delivered. However, there are disparities in utilization between black and non-black Americans, in part due to systemic biases and barriers in access to care.
The goal of this analysis is to assess trends in the uptake of shorter radiation regimes where a focus on the data for prostate cancer and assess rates of treatment non-completion. The hypothesis here is that black patients may have higher rates of non-completion overall, though this would be eliminated with the use of shorter hypofractionated radiation regimes. Further, the authors hypothesized that black patients would be less likely to receive hypofractionated regimes despite these potential clinical benefits. So the authors use the NCDB participant utilization files from 2004 until 2017. In the prostate cancer cohort, they focused on patients with localized disease, N0M0, who received definitive radiotherapy that is without radical prostatectomy. Patients were stratified by risk group according to NCCN and AUA or ASTRO criteria.
The primary outcome was treatment non-completion. This was defined as the receipt of less than the total number of fractions prescribed based on the treatment regime administered and the dose per fraction was calculated. Secondary outcome was utilization of a shorter course radiation approach. And so from the context of prostate radiation, we looked at moderately hypofractionated or SBRT approaches. And the completion threshold for prostate was defined for conventional fractionation as 41 to 48 fractions of 1.8 grade per fraction was administered, or 37 to 40 fractions if two grade per fraction was administered.
Patients with moderate hyperfractionation of 28 to 40 fractions was considered a completion threshold, and for SBRT, five to eight fractions was considered a complete course.
The authors used trend plots to assess the uptick of shorter regimes as well as treatment non-completion rates over time. And these were performed stratified by race as well as fractionation and/or radiation approach. Logistic regression analysis were used to assess predictors of both the primary and secondary outcomes. Covid variants included sociodemographic characteristics of the patient, clinical characteristics, and prostate specific features including NCCN risk group. I'm going to hand it over to Zach now to walk us through the results of this analysis.
Zach Klaassen: Thanks so much, Chris. So, if we look at the prostate cancer's specific core, we see that there was 170,386 identified in the NCDB. Among these patients, there was 9,852 that underwent S B R T 3,950 that underwent moderate hypofractionation for external beam radiotherapy and 156,584 that underwent conventional external beam radiotherapy.
This table looks at the prostate cancer baseline cohort, the characteristics by race, and we can see here that among white and black patients, the black patients were younger at 66 median years of age versus 71 for white patients. We see that with regards to insurance status, it was relatively well-balanced among these groups with the majority of patients, roughly 65 to 69% having government insurance. With regards to urbanicity, the majority of these patients, 80 to 90% were metro. With regards to household income, we see that there was quite a wide variation amongst black versus white men.
White men, 40% had a median household income greater than $63,000 compared to 20% for black men. With regards to the Charleston comorbidity score, this is relatively well balanced between these groups as well as well-balanced between disease characteristics with the majority of the patients, roughly 48% having intermediate risk disease and 33% having high risk disease. When we look at treatment characteristics, we see that the majority of these patients had conventional external beam radiotherapy with no real differences between race.
Moving to the right side of this panel, you can see here that hormone therapy was given in roughly 50% of cases. Roughly 50% of patients were in a community setting, and the other 50% academic setting. And with regards to distance room facility, we see that roughly 50%, 53% of patients that were white were less than 10 miles from their facility compared to 71% that were black. And we see that there was some variation with regards to greater distances greater than 50 miles, 7% of patients that were white and 2.5% that were black.
The next several slides, we'll look at several tables looking at the outcomes and as most UroToday listeners and readers will note the NCDB is that these studies have a lot of data. So I've highlighted in green boxes some of the key points that we'll discuss over the next several slides.
So this is the first of two slides looking at multiple linear regression modeling for treatment, non-completion and receipt of shorter regimens. Receipt of shorter regimens is on the right and to the left of that is treatment noncompletion. And so we see that among black men, they had an increased odds of having treatment non-completion at an odds ratio of 1.07 and a decreased odds of receiving shorter regimens of radiotherapy at odds ratio of 0.83. With regards to treatment non-completion, men that were older had a decreased odds of treatment non-completion for 50 to 64 years of age and greater than 65 years of age compared to younger men.
If we jumped down to urbanicity, those that were in urban and rural communities had increased odds of treatment non-completion and also a decreased odds of receipt of shorter regimens of radiotherapy. And we see interestingly, in the zip code with median household income, those with the high median household income had an increased odds of treatment, non-completion odds ratio of 1.16. And with increasing median income, there was increasing odds of receipt of shorter regimens of radiotherapy.
In the second panel, we see not surprisingly, that with regards to risk groups, increased risk of prostate cancer was associated with increased treatment non-completion, as well as decreased odds of receipt of shorter regimens of radiotherapy.
Moving down to hormone therapy, we see that men that received hormone therapy had decreased odds of receipt of shorter regimens of radiotherapy, and in terms of academic versus community locations of the practice, those that were treated in academic centers had a decreased odds of treatment non-completion and an increased odds of receiving shorter regimens of radiotherapy.
This figure looks at trends in treatment, non-completion and receipt of shorter regimens of radiotherapy. We can see that in the solid blue line, which represents black non-completion, this decreased over time, which was sort of mirroring the white non-completion rate, but at a lower rate for white patients. So we see that generally this is followed up a favorable trend, but slightly decreased among black men. With regards of receipt of stereotactic body radiotherapy or moderate hypofractionation, again, we see a similar trend among black and white men with increasing utilization over the years, but slightly less among black men, which seems to be, as we can see at the right of this figure improving over the last several years.
This figure looks at multiple linear regression modeling for treatment non-completion stratified by race. And I've highlighted here in the red box a key finding in this study. So among black men, if they received moderate or hypofractionated external beam radiotherapy, they were more likely to complete radiotherapy, which was also seen among white men. So despite a disparity of treatment non-completion, if these black men were offered moderate, or hypofractionated external beam radiotherapy, they were more likely to complete their treatment regimen.
Among black men, we see that an urban dwelling was associated with increased odds of treatment noncompletion, which is also seen in white men. And at the bottom again, we see a trend for increasing risk of disease. For intermediate and high risk, we see for both black and white men, an increased odds of treatment non-completion.
In the second panel, a couple of interesting points here among white men. Those that received hormone therapy had increased odds of treatment non-completion, which was not seen in black men. And among white men, those that were treated at an academic medical center had decreased odds of treatment non-completion, which was not seen in black men.
This final set of tables looks at multiple linear regression modeling for treatment non-completion broken down by a fractionation. So on this first column here, which I've highlighted in these boxes, this is for conventional external beam radiotherapy. So for this category for black men, they had increased odds of treatment non-completion when receiving external beam radiotherapy in a conventional manner, and in terms of year of diagnosis, we see an increasing year of diagnosis. So the more modern patients had a decreased odds of treatment non-completion when receiving conventional radiotherapy.
With regards to insurance status, those with government and an uninsured status compared to private insurance had a decreased odds of treatment non-completion. Again, we see urban and rural patients compared to metro patients had an increased odds of treatment non-completion for conventional radiotherapy. And again, with a high median household income of $63,000 or greater, higher odds of treatment non-completion, again, seen with intermediate and high-risk disease compared to low risk.
We move to moderate hypofractionation. We see that older men had an increased odds of treatment non-completion. Again, the patients that were treated more contemporarily had a lower odds of treatment non-completion. And we see this continual trend with higher risk disease having higher odds of treatment non-completion with moderate hypofractionation.
Again, with SBRT, we see year of diagnosis being significant, uninsured, a huge discrepancy here with the odds ratio of 4.64 for treatment, non-completion for stereotactic body radiotherapy. And again, this holds true for higher risk disease as we see at the bottom of this table.
To conclude the results here, we see that for academic centers for both conventional and moderate hypo fractionation, a decreased odds of treatment non-com completion and for hormone therapy for body radiotherapy odds ratio is 3.75 for treatment non-completion for those that received hormone therapy compared to those that did not. So by way of discussion, in this large national study of patients who received radiation for curable prostate cancer, shorter regimens of radiotherapy were associated with lower odds of treatment non-completion.
While black men who received conventional external beam radiotherapy had disproportionately higher rates of non-completion, this was not observed in a stereotactic body radiotherapy or moderate hyper fractionation external beam radiotherapy cohorts. Collectively, these findings suggest that shorter radiation regimens should be explored as a means of reducing non-completion. This also highlights the need to improve access to shorter radiation regimens, particularly among vulnerable populations who face persistent structural barriers to higher quality cancer care.
In addition to being more logistically feasible, short courses of radiation may be more affordable, offering greater convenience with potentially less financial toxicity. In conclusion, disparities in the receipt of shorter radiation regimens among black patients with prostate cancer persisted despite evidence suggesting that hypofractionation improves the likelihood of treatment completion. These findings underscore the need to identify and meaningfully addresses barriers to successful treatment with high quality radiotherapy as part of larger efforts to combat racial bias at inequities and access to cost-effective cancer care. Thank you very much for your attention and we hope you enjoyed the UroToday Journal Club discussion.
Chris Wallis: Hello, and thank you for joining us for UroToday Journal Club discussion. Today we're talking about a paper entitled Shorter Radiation Regimens and Treatment Non-Completion Among Patients with Breast and Prostate Cancer in the United States: An Analysis of Racial Disparities in Access and Quality. I'm Chris Wallis an Assistant Professor in the division of Urology at the University of Toronto. With me today is Zach Klaassen, an Assistant Professor in the Division of Urology at the Medical College of Georgia.
You can see here the citation for this recent publication, by way of background, breast and prostate cancer account for together more than 40% of all cancers that are treated with radiotherapy in the United States. Historically, for both of these conditions, radiotherapy has been administered with conventional fractionation, which comprises more than 40 treatments for patients with prostate cancer and more than 20 treatments for those with breast cancer.
However, recently hypofractionation has been shown to have comparable oncologic efficacy in both disease states. Hypofractionation offers a number of potential benefits to patients as well as to the healthcare system in terms of both cost and convenience. An important benefit of hypofractionation is improved treatment completion because with fewer treatments to administer and fewer to be received by the patient it is more likely that patients will receive all their therapy. Thus, overall adoption of hypofractionation may actually improve the quality of radiotherapy delivered. However, there are disparities in utilization between black and non-black Americans, in part due to systemic biases and barriers in access to care.
The goal of this analysis is to assess trends in the uptake of shorter radiation regimes where a focus on the data for prostate cancer and assess rates of treatment non-completion. The hypothesis here is that black patients may have higher rates of non-completion overall, though this would be eliminated with the use of shorter hypofractionated radiation regimes. Further, the authors hypothesized that black patients would be less likely to receive hypofractionated regimes despite these potential clinical benefits. So the authors use the NCDB participant utilization files from 2004 until 2017. In the prostate cancer cohort, they focused on patients with localized disease, N0M0, who received definitive radiotherapy that is without radical prostatectomy. Patients were stratified by risk group according to NCCN and AUA or ASTRO criteria.
The primary outcome was treatment non-completion. This was defined as the receipt of less than the total number of fractions prescribed based on the treatment regime administered and the dose per fraction was calculated. Secondary outcome was utilization of a shorter course radiation approach. And so from the context of prostate radiation, we looked at moderately hypofractionated or SBRT approaches. And the completion threshold for prostate was defined for conventional fractionation as 41 to 48 fractions of 1.8 grade per fraction was administered, or 37 to 40 fractions if two grade per fraction was administered.
Patients with moderate hyperfractionation of 28 to 40 fractions was considered a completion threshold, and for SBRT, five to eight fractions was considered a complete course.
The authors used trend plots to assess the uptick of shorter regimes as well as treatment non-completion rates over time. And these were performed stratified by race as well as fractionation and/or radiation approach. Logistic regression analysis were used to assess predictors of both the primary and secondary outcomes. Covid variants included sociodemographic characteristics of the patient, clinical characteristics, and prostate specific features including NCCN risk group. I'm going to hand it over to Zach now to walk us through the results of this analysis.
Zach Klaassen: Thanks so much, Chris. So, if we look at the prostate cancer's specific core, we see that there was 170,386 identified in the NCDB. Among these patients, there was 9,852 that underwent S B R T 3,950 that underwent moderate hypofractionation for external beam radiotherapy and 156,584 that underwent conventional external beam radiotherapy.
This table looks at the prostate cancer baseline cohort, the characteristics by race, and we can see here that among white and black patients, the black patients were younger at 66 median years of age versus 71 for white patients. We see that with regards to insurance status, it was relatively well-balanced among these groups with the majority of patients, roughly 65 to 69% having government insurance. With regards to urbanicity, the majority of these patients, 80 to 90% were metro. With regards to household income, we see that there was quite a wide variation amongst black versus white men.
White men, 40% had a median household income greater than $63,000 compared to 20% for black men. With regards to the Charleston comorbidity score, this is relatively well balanced between these groups as well as well-balanced between disease characteristics with the majority of the patients, roughly 48% having intermediate risk disease and 33% having high risk disease. When we look at treatment characteristics, we see that the majority of these patients had conventional external beam radiotherapy with no real differences between race.
Moving to the right side of this panel, you can see here that hormone therapy was given in roughly 50% of cases. Roughly 50% of patients were in a community setting, and the other 50% academic setting. And with regards to distance room facility, we see that roughly 50%, 53% of patients that were white were less than 10 miles from their facility compared to 71% that were black. And we see that there was some variation with regards to greater distances greater than 50 miles, 7% of patients that were white and 2.5% that were black.
The next several slides, we'll look at several tables looking at the outcomes and as most UroToday listeners and readers will note the NCDB is that these studies have a lot of data. So I've highlighted in green boxes some of the key points that we'll discuss over the next several slides.
So this is the first of two slides looking at multiple linear regression modeling for treatment, non-completion and receipt of shorter regimens. Receipt of shorter regimens is on the right and to the left of that is treatment noncompletion. And so we see that among black men, they had an increased odds of having treatment non-completion at an odds ratio of 1.07 and a decreased odds of receiving shorter regimens of radiotherapy at odds ratio of 0.83. With regards to treatment non-completion, men that were older had a decreased odds of treatment non-completion for 50 to 64 years of age and greater than 65 years of age compared to younger men.
If we jumped down to urbanicity, those that were in urban and rural communities had increased odds of treatment non-completion and also a decreased odds of receipt of shorter regimens of radiotherapy. And we see interestingly, in the zip code with median household income, those with the high median household income had an increased odds of treatment, non-completion odds ratio of 1.16. And with increasing median income, there was increasing odds of receipt of shorter regimens of radiotherapy.
In the second panel, we see not surprisingly, that with regards to risk groups, increased risk of prostate cancer was associated with increased treatment non-completion, as well as decreased odds of receipt of shorter regimens of radiotherapy.
Moving down to hormone therapy, we see that men that received hormone therapy had decreased odds of receipt of shorter regimens of radiotherapy, and in terms of academic versus community locations of the practice, those that were treated in academic centers had a decreased odds of treatment non-completion and an increased odds of receiving shorter regimens of radiotherapy.
This figure looks at trends in treatment, non-completion and receipt of shorter regimens of radiotherapy. We can see that in the solid blue line, which represents black non-completion, this decreased over time, which was sort of mirroring the white non-completion rate, but at a lower rate for white patients. So we see that generally this is followed up a favorable trend, but slightly decreased among black men. With regards of receipt of stereotactic body radiotherapy or moderate hypofractionation, again, we see a similar trend among black and white men with increasing utilization over the years, but slightly less among black men, which seems to be, as we can see at the right of this figure improving over the last several years.
This figure looks at multiple linear regression modeling for treatment non-completion stratified by race. And I've highlighted here in the red box a key finding in this study. So among black men, if they received moderate or hypofractionated external beam radiotherapy, they were more likely to complete radiotherapy, which was also seen among white men. So despite a disparity of treatment non-completion, if these black men were offered moderate, or hypofractionated external beam radiotherapy, they were more likely to complete their treatment regimen.
Among black men, we see that an urban dwelling was associated with increased odds of treatment noncompletion, which is also seen in white men. And at the bottom again, we see a trend for increasing risk of disease. For intermediate and high risk, we see for both black and white men, an increased odds of treatment non-completion.
In the second panel, a couple of interesting points here among white men. Those that received hormone therapy had increased odds of treatment non-completion, which was not seen in black men. And among white men, those that were treated at an academic medical center had decreased odds of treatment non-completion, which was not seen in black men.
This final set of tables looks at multiple linear regression modeling for treatment non-completion broken down by a fractionation. So on this first column here, which I've highlighted in these boxes, this is for conventional external beam radiotherapy. So for this category for black men, they had increased odds of treatment non-completion when receiving external beam radiotherapy in a conventional manner, and in terms of year of diagnosis, we see an increasing year of diagnosis. So the more modern patients had a decreased odds of treatment non-completion when receiving conventional radiotherapy.
With regards to insurance status, those with government and an uninsured status compared to private insurance had a decreased odds of treatment non-completion. Again, we see urban and rural patients compared to metro patients had an increased odds of treatment non-completion for conventional radiotherapy. And again, with a high median household income of $63,000 or greater, higher odds of treatment non-completion, again, seen with intermediate and high-risk disease compared to low risk.
We move to moderate hypofractionation. We see that older men had an increased odds of treatment non-completion. Again, the patients that were treated more contemporarily had a lower odds of treatment non-completion. And we see this continual trend with higher risk disease having higher odds of treatment non-completion with moderate hypofractionation.
Again, with SBRT, we see year of diagnosis being significant, uninsured, a huge discrepancy here with the odds ratio of 4.64 for treatment, non-completion for stereotactic body radiotherapy. And again, this holds true for higher risk disease as we see at the bottom of this table.
To conclude the results here, we see that for academic centers for both conventional and moderate hypo fractionation, a decreased odds of treatment non-com completion and for hormone therapy for body radiotherapy odds ratio is 3.75 for treatment non-completion for those that received hormone therapy compared to those that did not. So by way of discussion, in this large national study of patients who received radiation for curable prostate cancer, shorter regimens of radiotherapy were associated with lower odds of treatment non-completion.
While black men who received conventional external beam radiotherapy had disproportionately higher rates of non-completion, this was not observed in a stereotactic body radiotherapy or moderate hyper fractionation external beam radiotherapy cohorts. Collectively, these findings suggest that shorter radiation regimens should be explored as a means of reducing non-completion. This also highlights the need to improve access to shorter radiation regimens, particularly among vulnerable populations who face persistent structural barriers to higher quality cancer care.
In addition to being more logistically feasible, short courses of radiation may be more affordable, offering greater convenience with potentially less financial toxicity. In conclusion, disparities in the receipt of shorter radiation regimens among black patients with prostate cancer persisted despite evidence suggesting that hypofractionation improves the likelihood of treatment completion. These findings underscore the need to identify and meaningfully addresses barriers to successful treatment with high quality radiotherapy as part of larger efforts to combat racial bias at inequities and access to cost-effective cancer care. Thank you very much for your attention and we hope you enjoyed the UroToday Journal Club discussion.