Functional Disability Among US Cancer Survivors

Dr. Shannon Westin and her guest, Dr. Chao Cao, discuss the paper "Prevalence and Cancer-Specific Patterns of Functional Disability Among US Cancer Survivors, 2017-2022" recently published in the JCO.

TRANSCRIPT

The guest on this podcast episode has no disclosures to declare. 

Dr. Shannon Westin: Hello, everyone, and welcome to another episode of JCO After Hours, the podcast where we get in depth with authors and manuscripts that have been published in the Journal of Clinical Oncology. I'm your host, Shannon Westin, gynecologic oncologist by trade and Social Media Editor for the JCO. And it is my pleasure to welcome Dr. Cao, a research fellow in medicine, Department of Medical Oncology, Dana Farber, Cancer Institute, Boston, Massachusetts. Welcome.

Dr. Cao: Thanks for having me.

Dr. Shannon Westin: Of course. And we're going to be discussing your very important work, “The Prevalence and Cancer Specific Patterns of Functional Disability Among US Cancer Survivors, 2017-2022,” which was published in the Journal of Clinical Oncology on April 4, 2024. And Dr. Cao has no conflicts of interest in regards to this podcast. 

So let's get right into it. I'd love to level set. Can you speak a little bit about the definition of cancer survivorship and the number of cancer survivors currently in the United States? 

Dr. Cao: I think this is an important question because everyone somewhat has confusion about the definition of cancer survivorship. So based on the definition by the National Cancer Institute, cancer survivorship refers to the phase of life following the diagnosed cancer. And nowadays, it's estimated about 80 million American individuals are living after being diagnosed with cancer. And this number is projected to rise to 26 million by 2040.

Dr. Shannon Westin: Wow. So obviously, any research that we can do in this population is going to be so important as that number absolutely continues to grow. 

And before we get into the specifics of your work, I'd love for you to speak a little bit about the importance of functional disability, which is what we studied in this work and why it might be observed in cancer survivors. 

Dr. Cao: Yeah, sure. So, maintaining physical function is fundamental to perform life tasks and engage in fruitful jobs. In terms of cancer survivors, many cancer survivors experience side effects from cancer and its treatment. These side effects, include the pain, fatigue, and musculoskeletal dysfunction, which can induce physical limitation and eventually physical disability. And specifically, this is such a burden for the US, social, societal and economic burden. Here I have the specific number: so in 2019, an estimate of over 100,000 people living with and beyond cancer were unable to work and they received a Social Security Administration disability benefit with the resulting cost of US$1.8 billion in disability claims.

Dr. Shannon Westin: Wow. We always think about the impact on the survivor, on their family, but I think it's also really important to look at those other objective data about the impact on society as a whole. Thank you, that was great detail.  

Do we know anything about who might be proportionately more affected by cancer induced physical impairments and disabilities?

Dr. Cao: Actually, this is our key question for our manuscript, but before we developed our hypothesis, we also looked at the data from the general population. So we observed that visual minorities and underserved populations, such as people with lower socioeconomic status and living in the rural area, and also those with unhealthy types of behavior, for example, smoking, obesity, and physical inactivity, are more likely to have physical limitations and disabilities. And also the comorbidity in cancer survival, such as diabetes, cardiovascular disease, also increase the likelihood of physical disability. We also have cancer survivors, particularly for cancer patients who are currently receiving cancer treatment, for example, chemotherapy and radiation therapy, they also are more likely to report side effects from the treatment, also have the reduced physical function. So we also think the cancer patients during the treatment also have a higher likely chance to have physical disability.

Dr. Shannon Westin: Absolutely. That makes sense, and that really dovetails nicely into the objective of your study. We'd love for you to briefly summarize your objective and the methods you employed to achieve that goal. 

Dr. Cao: Yeah, sure. We used the six-year data, 2017 to 2022 from the Behavioral Risk Factor Surveillance System to investigate problems and factors of functional disability in over 47,000 cancer survivors and 2.4 million adults without cancer diagnosis aged 80 years and older. And we specifically focused on two types of functional disability. The first one is mobility disability, which is defined as self reported severe difficulty walking or climbing stairs. And also another one is self care disability, which is defined as self reported difficulty dressing or bathing. And also we examined the factors, for example, social demographic characteristics, lapse of behavior, and health related factors, and some cancer related factors, how these factors related to the functional disability.

Dr. Shannon Westin: Okay, great. So before we get into your findings, I'd love to hear just a little bit more about the BRFSS, the Behavioral Risk Factor Surveillance System. Why did you choose data from this survey for your study? 

Dr. Cao: This is a very key question, because nowadays there are no specific cohort studies for cancer survivors. And also actually, in the population based study, there is no field data specifically for the cancer survivor. But fortunately, in the United States, the CDC conducted several nationally representative surveys to examine the health status of the people living in the United States. So we used the data from the Behavioral Risk Factor Survival System, we also called BRFSS. So BRFSS is a nationwide telephone based survey conducted by the CDC and it collects information on health related risk factors and chronic micro conditions among the US adults aged 80 years or older. And specifically for our papers, because recently, the BRFSS also added a section on the cancer survivorship, which included a lot of the variables on cancer, diagnosed cancer type, and also cancer related factor symptoms, for example, the cancer or cancer treatment related pain. So we used this data to realize our idea. 

Dr. Shannon Westin: Okay, great. So let's start with what you found in regards to the first aspect with mobility disability. 

Dr. Cao: First, we observed the problems of mobility stability are much higher in cancer survivors than non-cancer adults. And also among cancer survivors, more than 25% of cancer survivors reported mobility disability. We also observe the prevalence of mobility disability is much higher in racial minority groups and underserved populations and those with unhealthy behavior and medical conditions.

Dr. Shannon Westin: In addition to the underrepresented minorities, were there any other kind of socioeconomic, demographic factors associated with high prevalence of mobility disability?

Dr. Cao: Yes, the factors like lower level of education, income, being unmarried, and living in non metropolitan areas were associated with higher prevalence of mobility disability. And also, I forgot to mention another factor is cancer related factors. We're also including several cancer related factors such as cancer and cancer related pain. So we also observed a higher prevalence of the mobility disability in people, in cancer survivors with cancer and cancer related pain. We also see the prevalence of the mobility disability is much higher in the patients who are currently receiving the cancer treatment than those who already completed the cancer treatment.

Dr. Shannon Westin: Yeah, that makes a lot of sense. And to that end, with regards to treatment, were there any cancer specific patterns of mobility disability?

Dr. Cao: Yeah, and also, I think this is another strength of our study, because the BRFSS high sample size, which clearly evaluates the mobility disability in over 47,000 cancer survivors,  which allowed us to do the cancer specific part of mobility disability. We observed that the survivors of lung cancer and brain cancer and bone cancer have the highest prevalence of mobility disability. And interestingly, we also observed that the women with cancers also had, for example, ovary, cervical cancer survivors also have higher problems of mobility disability. Probably you know, better than me, and I just tell the data.

Dr. Shannon Westin: Well, it’s interesting, I was thinking, it seems like we have a lot, but I have no, obviously, frame of reference with other cancer types. So it's intriguing to me that that's definitely what we see in our clinic. So I'm intrigued to understand more about this. 

But before we get into the next steps and that type of thing, I do want to make sure we touch on that other aspect that you looked at, the self care disability and give the listeners a little bit of an idea of what you found there? 

Dr. Cao: The self care disability is kind of the more severe of the functional disability, which means, we say candidates, lower prevalence compared to the mobility disability, but still the patterns or factors associated with self care disability are much similar with mobility disability. An interesting finding is that in terms of the mobility disability, we find that older survivors are more likely to report mobility disability than younger survivors. In contrast, in terms of the self care disability, younger survivors are more likely to report than the older cancer survivors. 

Dr. Shannon Westin: You've touched a little bit on some of the socioeconomic and demographic factors that were different with self care disability. Was there anything else that really caught your eye? Cancer specific factors or anything else like that?

Dr. Cao: Yeah, besides this, I think also we observe that women are more likely to report self care disability. I think also this is driven by the cancer specific, particularly the woman cancers have a higher prevalence of the self care disability.

Dr. Shannon Westin: Well, it's definitely something for me to take back to my clinic. Now that you've covered all these results, how are your data compared to existing literature in this area? 

Dr. Cao: Yeah, we have tended to do comprehensive literature reviews. When we discuss our results and compare it with existing literature, our result is quite aligned with previous literature and particularly we clearly see the racial ethnic minority have a higher prevalence of physical limitation and physical function decline. But our paper focused on the physical disability which is much more severe than the physical function. And also we also looked at another study conducted in Australia, we quite find very similar results even for cancer specific patterns of the functional disability. 

Dr. Shannon Westin: I guess the next question I have is was there anything that surprised you about your results? 

Dr. Cao: I just mentioned that what surprised me the most is that the older people are more likely to report the mobility disability, but the younger people are more likely to report self care disability. Our data don't support or explore why this happened and what's the etiology behind this. But our hypothesis is that the younger cancer survivor, younger cancer patients are more likely to receive the aggressive treatment that can play a significant role in the functional outcome. 

Dr. Shannon Westin: Yeah, it sounds like that's definitely an area of unmet need for more research. But I like your hypothesis. I do wonder if that's somewhat related.  

And I guess that leads us to our final question. What are your next steps and how can I potentially use this in practice? How can our listeners employ these findings in their practice? What do you recommend?

Dr. Cao: I think our findings highlight the importance of screening for functional limitations at the baseline and throughout the cancer treatment and even the cancer survivorship. Oncology providers also should encourage patients to be physically active. And also American Society of Clinical Oncology and also American College of Sports Medicine recommend that regular exercise during the treatment can help cancer patients preserve their fitness and reduce the incidence and the severity of the cancer related disability. And also providers can provide referral to rehabilitation services and support groups for additional care. 

For the next step, our finding highlights the importance of developing ways to limit the long term side effects of cancer treatment both during and after treatment to preserve fixed function and prevent disability. Particularly, target intervention should in particular address special needs in vulnerable populations, including the racial ethnic minorities and those living in the rural areas to improve their quality of life during a long term survivorship. And also due to the advance in the technologies, now we want to see whether wearable sensors, wearable devices can be a novel tool to monitor their physical functions during the treatment because better monitors can lead into their better treatment and their prevention.

Dr. Shannon Westin: That's great. Yeah, what a great way to end. I think that exercise clearly is key not only for preventing these issues, but also we know that it potentially can even improve response to therapy and recurrence free survival. So I think lots of reasons to be focusing on physical activity in our clinics and ensuring our patients and our cancer survivors are really participating in those types of activities. 

Well, Dr. Cao, it was such a pleasure. I cannot believe you are only a research fellow. I can't wait to see where your career takes you. Congratulations on this great work.

Dr. Cao: Thank you. Thank you for this great opportunity to share my work and I look forward for my future work in the field.

Dr. Shannon Westin: Oh, yeah. So you guys, if you're looking for somebody to come and push the boundaries of functional disability and activity, you know where to look. 

And again, thank you all our listeners for tuning in to another episode of JCO After Hours. Again, we were discussing, “The Prevalence and Cancer Specific Patterns of Functional Disability Among US Cancer Survivors, 2017-2022.” Original research published in the JCO, April 4th, 2024. So if you're looking for more podcast offerings, check out other JCO After Hours offerings wherever you get your podcasts. Have an awesome day.

 

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