Cancer care has become increasingly sophisticated in measuring tumors, treatment response, laboratory values, and survival. Yet one critically important question is often assessed much less precisely:
What can the patient physically do?
A 2026 study published in Scientific Reports, “The Senior Fitness Test for assessing functional fitness in cancer patients and survivors: a cross-sectional study,” provides an important argument for making objective functional assessment a routine component of Exercise Oncology.
Cancer Can Make the Body Functionally “Older”
The investigators studied 30 cancer patients and survivors with an average chronological age of approximately 62 years. Sixteen were undergoing treatment and 14 had completed treatment. Participants represented multiple cancers and stages, including 11 individuals with Stage IV disease.
Each participant completed the Senior Fitness Test (SFT), a standardized battery assessing six important dimensions of physical function:
- Lower-body strength
- Upper-body strength
- Lower-body flexibility
- Upper-body flexibility
- Agility and balance
- Aerobic endurance
These are measured through the 30-second chair stand, arm curl, chair sit-and-reach, back scratch, Timed Up-and-Go, and two-minute step tests.
The researchers then compared performance with age- and sex-specific normative values to calculate a composite “Fitness Age.”
The result is striking; participants had an average Fitness Age approximately 8.6 years older than their chronological age.
In other words, a person may be 62 chronologically while functioning physically more like someone around 70.
Importantly, “Fitness Age” should not be confused with biological age. The authors specifically describe it as an aggregate measure of deviation from age-related norms across several dimensions of physical performance.
ECOG May Not Tell the Whole Story
Perhaps the most important finding for oncology practice involves the commonly used Eastern Cooperative Oncology Group (ECOG) Performance Status.
ECOG is valuable for clinical decision making, but it is a clinician-rated, single-item measure. It does not objectively measure strength, endurance, flexibility, mobility or balance.
In this study, differences in Fitness Gap were not statistically significant between patients classified as fully active (ECOG 0) and those with functional limitations (ECOG >0). The authors conclude that performance-based testing can reveal meaningful impairments that ECOG alone may fail to identify.
This has major implications for Exercise Oncology.
A patient can appear clinically “fully active” while still having substantial deficits in muscular strength, aerobic capacity, flexibility, balance or mobility.
The Deficits Don’t Necessarily End When Treatment Ends
Another important finding was that the Fitness Gap was similar in patients receiving active treatment and those who had completed treatment.
The investigators found an average gap of 8.11 years during treatment versus 9.13 years after treatment, with no statistically significant difference.
Although this small cross-sectional study cannot establish how an individual’s function changes over time, the finding reinforces an important Exercise Oncology principle: completion of cancer treatment does not necessarily mean recovery of physical function.
Functional impairment may continue into survivorship, supporting the need for exercise programming across the entire cancer continuum—not simply during chemotherapy, radiation or surgery.
Why This Study Matters for Organizing Exercise Oncology Programs
This publication is especially important because it helps answer a practical question: How should an Exercise Oncology Program determine what exercise a patient needs?
Exercise prescription should not begin with assumptions based solely on age, cancer diagnosis, treatment status or ECOG score. It should begin with measurement.
The SFT provides one potential framework.
For an organized Exercise Oncology Program, objective functional testing could create a pathway for:
Assess → Identify deficits → Prescribe → Exercise → Reassess → Modify the prescription
The study demonstrates that the SFT is particularly attractive operationally because all participants completed the testing without reported adverse events, and the complete assessment took approximately 20–30 minutes.
More importantly, its individual components can identify where the problem exists. For example, a patient might have acceptable upper-body strength but poor aerobic endurance, impaired lower-body strength and diminished balance. That patient should not simply receive generic advice to “exercise more.”
The program can target the identified deficits.
The study’s results illustrate this concept particularly well: the largest average Fitness Gap among the six tests occurred with the two-minute step test, an indicator of aerobic endurance, at 16.1 years.
Objective Testing Can Become Part of the Exercise Oncology Infrastructure
For CancerFitness.org, this publication supports a broader concept: Exercise Oncology should increasingly function like other evidence-based clinical disciplines, measure first, prescribe second, and measure again.
A well-organized program could incorporate standardized functional assessments at several points: before treatment when feasible, during treatment, at completion of treatment, and periodically throughout long-term survivorship.
That approach could allow Exercise Oncology professionals to document functional deterioration, individualize aerobic and resistance training, identify balance or mobility problems, demonstrate improvement, communicate objective results back to oncology teams, and build measurable outcomes into quality-improvement and research programs.
The authors support incorporating brief validated objective assessments, including the SFT, gait speed, Timed Up-and-Go and six-minute walk testing, into oncology care to identify functional impairments earlier and facilitate referral to targeted exercise or rehabilitation.
An Important Study—But Not Yet a Definitive Standard
The findings should be interpreted appropriately. This was an exploratory study involving only 30 participants at a single German center, with multiple cancer diagnoses, stages and treatments. There was no control group, and the cross-sectional design cannot establish causation or demonstrate that improving the Fitness Gap improves survival or treatment outcomes.
The researchers appropriately call for larger prospective studies to determine whether these measurements can predict outcomes such as treatment tolerance, hospitalization, functional decline or survival.
Therefore, the study does not establish the SFT as the universal assessment standard for Exercise Oncology.
What it does establish is an important principle:
We should not assume that we understand a cancer patient’s physical function simply because we know the patient’s age, treatment status and ECOG score.
The CancerFitness.org Perspective
The future of Exercise Oncology should move beyond simply recommending physical activity.
Patients need assessment-driven, individualized exercise prescriptions based upon their actual functional capabilities and limitations.
This study provides a practical model for accomplishing that goal. Objective testing can uncover deficits that routine oncology performance assessments may miss and can provide Exercise Oncology professionals with measurable information for designing, and subsequently evaluating, individualized interventions.
The authors conclude that integrating objective functional measures into cancer care may help identify deficits earlier and inform individually tailored exercise interventions aimed at preserving long-term functional independence and quality of life.
Call to Action
Cancer centers, oncology practices and survivorship programs should consider objective functional assessment an essential component when developing Exercise Oncology services.
Exercise Oncology should not be reduced to telling patients to “stay active.” Programs should develop standardized pathways to assess physical function, prescribe individualized exercise, monitor progress and reassess outcomes throughout treatment and survivorship.
For patients and survivors, the message is equally important: ask your cancer care team not only whether you should exercise, but whether your strength, endurance, mobility, flexibility and balance can be objectively assessed, and whether those results can be used to create an exercise program specifically for you.
At CancerFitness.org, we believe the next stage of Exercise Oncology is not simply getting more people with cancer to exercise. It is building a system in which exercise is assessed, prescribed, monitored and adjusted as an integral component of comprehensive cancer care.
Reference: The Senior Fitness Test for assessing functional fitness in cancer patients and survivors: a cross-sectional study. Frieder Krause, Sofie Nieland, Katharina Graf, Elke Jäger & Lutz Vogt. Scientific Reports (2026) 16:24533 https://doi.org/10.1038/s41598-026-66221-w
