Javier Torres-Roca, Professor in Radiation Oncology at Moffitt Cancer Center, shared a post on LinkedIn:
“Why We Still Don’t Know the Right Radiation Dose.
Radiation therapy is used in the care of roughly 60% of cancer patients.
It is one of the most precise modalities in medicine. And yet, there’s an uncomfortable truth we don’t talk about enough: We still don’t really know the right radiation dose for most patients.
Despite decades of advances in imaging, planning software, and delivery technology, radiation dose selection remains largely empirical.
We rely on population-based prescriptions that have changed surprisingly little over time (except for the development of hypofractionated schedules), even as everything else around them has become more sophisticated.
Two patients. Same cancer type. Same stage. Same radiation dose.
Completely different outcomes. One is cured. Another recurs—or experiences significant toxicity.
We’ve learned to accept this variability as inevitable.
We call it ‘tumor biology’ or ‘patient heterogeneity’ and move on. But acceptance isn’t the same as understanding—and it certainly isn’t the same as optimizing outcomes.
Radiation oncology has made extraordinary progress in how radiation is delivered. We plan with millimeter precision.
We sculpt dose around critical structures. We optimize geometry, margins, and organs at risk with remarkable rigor.
What we don’t routinely plan around is the thing that ultimately determines response: tumor biology.
Physical dose is a convenient metric, but it’s a poor surrogate for biological effect. A given dose does not mean the same thing biologically from one tumor to another.
When dose escalation trials fail, or when toxicity outweighs benefit, it’s tempting to conclude that ‘more radiation doesn’t work.’
But a different interpretation is equally plausible: We escalated dose without knowing whether it was biologically relevant—or necessary—in the first place.
Patients don’t experience physics.
They experience biology.
If two tumors respond differently to the same physical dose, the failure isn’t in delivery. It’s in the assumption that dose alone captures biological effect.
So the real question isn’t whether radiation therapy works.
It clearly does.
The question is whether we’re ready to move beyond one-size-fits-all dosing and start asking a more fundamental one: What radiation dose is biologically appropriate for this tumor, in this patient?
Until we bring biology into the treatment planning room, we’ll continue to optimize what’s easy to measure—rather than what actually matters most.
Outcomes.”
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