BARCELONA-Handgrip strength (HGS) was found to be an independent quantitative marker for overall survival among patients with early-stage non-small cell lung cancer (NSCLC) being treated with stereotactic body radiotherapy (SBRT) in a study discussed at the 2018 European Society for Radiotherapy & Oncology (ESTRO 37) conference (Abstract PV-0041).
The investigators used a handgrip strength test before patients were treated with SBRT and followed them up for survival. "We saw that there was indeed a correlation between a weak handgrip strength and overall survival," said first author Stephanie Peeters, MD, PhD, a radiation oncologist from the MAASTRO Clinic in Maastricht, Netherlands.
At both 1- and 5-year follow-up, overall survival (OS) was significantly better in patients with good handgrip strength compared to those with weak handgrip strength. "The hazard ratio (HR) for this difference was 1.5-which is quite a lot," Peeters said. "At 1 year the difference in overall survival was about 10 percent. And at 5 years it was nearly 25 percent."
Only 12 percent of patients with handgrip weakness were alive 5 years later compared with 40 percent of those who had normal handgrip.
And HGS was a very easy clinical tool that could be used in daily clinical practice to guide therapeutic decisions, said Peeters. She didn't suggest clinicians use it alone but as an additional tool on top of existing prognostic assessment by scales such as World Health Organization performance status (PS). But the important difference was that HGS was an objective tool.
"First of all: we want to treat our patients in the best way. We need good tools to do that. And if we have good additional tools-in this case this handgrip strength-we can really make a difference to guide us in our therapeutic decisions," she said.
The Netherlands researchers had been aware that other prognostic scoring methods were partly subjective and failing to predict life expectancy with sufficient accuracy among elderly patients with early lung cancer who commonly had comorbidities. Patients were at risk of dying from causes other than cancer despite good oncological local responses to SBRT, noted Peeters.
She also mentioned that radiation oncologists often treated patients who had more comorbidities than those who went for surgery since SBRT was relatively gentle. "We get higher-risk patients because good risk ones get surgery." Apart from its subjectivity when PS was used alone, it also had the disadvantage that its influence on prognosis still needed validation, she said. So an objective assessment was needed.
Muscular strength had already been associated with mortality and morbidity in other diseases and could be measured by checking HGS.
In the study, all patients took the HGS test (with a hydraulic hand dynamometer) three times with each hand by gripping it as firmly as they could for 3 seconds. Handgrip weakness was defined as any maximal handgrip strength below "percentile 10" of UK Biobank reference values-taking gender, age, and height into account.
Two hundred twenty-six patients with stage I NSCLC were included who had a mean age of 72 +/- 9 years. Their mean BMI was 25.0 +/- 5.0 kg/m2. Fifty-nine percent of them were men and 41 percent women. Thirty-one percent of patients were found to have had handgrip weakness.
At 5 years follow-up, those with handgrip weakness had poorer survival (HR 1.49). Multivariate analysis revealed four factors were associated with poorer survival at 5 years: handgrip weakness (HR 1.52), male gender (HR 1.80), higher age (HR 1.03 per year), and lower BMI (HR 0.93 per kg/m2). Having a PS of two or more was not significantly prognostic. Even at 1 year follow-up handgrip was an independent prognostic factor for OS.
The investigators concluded that HGS was "an objective, cheap, and easy-to-measure independent prognostic parameter for short-and long-term OS in stage I NSCLC treated with SBRT."
"The idea of using this handgrip test is that you have an objective way: you end up with a number," said Peeters. "And that makes it very attractive-not to replace performance status but as an additional factor to make better decisions, possibly, in patients who are in the grey zone."
When asked about improvements the test could bring, she said that in patients with stage I NSCLC it could guide decisions about whether or not to treat. "In patients with a short overall survival (because of comorbidities), it's probably not necessary to treat these very small lesions because they will probably not die from them," she explained. "And although stereotactic treatment is easy and is well-tolerated it's still a treatment-and there are still consequences: and [it] can still give side effects."
Peeters also highlighted the need for better decision-making with patients who have lung cancer about whether to opt for surgery or SBRT. "Some patients are clearly not operable. But there is a "grey zone." And in this "grey zone" this factor can also help us to decide which treatment would be most suitable for these patients."
The President of ESTRO Yolande Lievens, MD, PhD, Head of the Department of Radiation Oncology at Ghent University Hospital in Belgium, commented that the study had shown that a simple test (measuring HGS) was a good prognostic approach. And she thought it could be used beyond early-stage NSCLC. "For example this will be very important for [patients with] locally advanced [disease] where you have to decide very often: Will they be fit enough to have concurrent chemo-radiotherapy over a longer time span? Will we not hamper their quality of life?"
The fact that HGS had been shown to help in a patient population with early lung cancer interested Lievens. "But to me there are more implications in the broader group of patients with lung cancer-but also outside of lung cancer," she said.
HGS was a test that had been shown to have "a very clear correlation with the outcome" of the patients, according to Lievens. "If we can go to something that's easy [and] reproducible why wouldn't we then just use it? Because I think it's a very nice way [of] optimizing the evaluation of the patient prior to treatment. And as health care professionals, we are always looking for something that is easy, valid, and that we can use in a simple way."
Peter M. Goodwin is a contributing writer.