When Physics Fights Cancer: The Invisible War Against Tumors

Not Just Blasting Tumors: Physics Meets Biology

The connection between physics and cancer might seem modern, but it dates back decades. The discovery of DNA's structure itself came from physicists Francis Crick and Maurice Wilkins working with biologists ² . What began with radiation therapy has now evolved into sophisticated approaches that address some of cancer's most challenging problems.

Radiation therapy, one of the cornerstones of cancer treatment, originated from basic physical chemistry research ² . Today, physics and mathematics are central to designing the accelerators that generate radiation and the algorithms that determine exactly where and how much radiation should be delivered to maximize damage to tumors while minimizing harm to healthy tissue ² .

This integration has deepened as researchers recognize that cancer behaves as a complex physical system with its own mechanics and evolutionary rules. Tumors aren't just masses of cells—they exist in a physical environment with forces, pressures, and mechanical properties that influence their growth and spread ² .

The Flash Breakthrough: When Less Time Makes All the Difference

One of the most exciting recent developments illustrates physics' growing role in cancer treatment. In a series of vast underground caverns on the outskirts of Geneva, Switzerland, researchers at CERN—the European Laboratory for Particle Physics, home to the Large Hadron Collider—are conducting experiments that may lead to a new generation of radiotherapy machines ¹ .

The Paradigm-Shifting Discovery

Eleven years ago, radiobiologist Marie-Catherine Vozenin and others published a landmark paper outlining a revolutionary approach called Flash radiotherapy ¹ . They discovered that by delivering radiation at ultra-high dose rates—with exposures of less than a second rather than minutes—they could destroy tumors in rodents while sparing healthy tissue ¹ .

The impact was immediate. International experts described it as a seminal breakthrough that galvanized researchers worldwide to conduct their own experiments with the Flash approach ¹ .

Why Flash Matters: The Precision Advantage

Conventional radiotherapy is typically delivered over several minutes, with total treatment spread across dozens of sessions over up to eight weeks ¹ . While advanced imaging has improved targeting, the risk of damaging healthy tissue remains a significant limitation, particularly for sensitive areas like the brain ¹ .

Flash addresses this fundamental challenge. Animal studies have repeatedly shown that Flash makes it possible to markedly increase the amount of radiation delivered to the body while minimizing impact on surrounding healthy tissue ¹ . In one experiment, healthy lab mice given two rounds of Flash radiation did not develop the typical side effects expected during the second round. In another study, animals treated with Flash for head and neck cancers experienced fewer side effects like reduced saliva production or difficulty swallowing ¹ .

Radiation Modalities Comparison

The Experimental Journey

The results have been compelling enough to move Flash into human trials. Cincinnati Children's Hospital is planning an early-stage trial in children with metastatic cancer that has spread to their chest bones, while Lausanne University Hospital in Switzerland is conducting a Phase 2 trial for patients with localised skin cancer ¹ .

The Physics of Cancer's Physical World

Beyond radiation therapy, physics provides crucial insights into cancer's mechanical properties. Since Egyptian times, physicians have noted that tumors are typically harder than surrounding tissue ² . This observation gave rise to the word "oncology" (from the Ancient Greek 'onkos,' meaning 'a mass') and continues to be used in cancer detection ² .

The Mechanics of Tumor Growth

Physics helps explain why tumors feel different from healthy tissue. Cancer cells and their environment engage in a continuous "tug-of-war" of physical forces ² . Cells monitor their surrounding tensile forces and chemicals, and different mechanochemical inputs change which genes the cell expresses, altering its cytoskeleton and changing its stiffness ² .

This mechanical dimension isn't just a side effect—it's fundamental to how cancer progresses. Tissue mechanics are now recognized as master regulators of cell behavior and organization ² . The physical forces arising from cell-cell and cell-matrix adhesion, surface tension, and intracellular molecular machines ultimately shape tumor architecture and behavior ² .

Essential Tools in Physics-Cancer Research

Beyond Radiation: Chaos Theory and Cancer's Unpredictable Nature

Perhaps the most abstract—and fascinating—application of physics to cancer comes from chaos theory. Some researchers have proposed the "Evolutionary Metabolic Hypothesis of Cancer," suggesting that increasing reactive oxygen species and intracellular inflammation cause damage to mitochondria, creating chaotic signaling in cells ⁶ .

While this application of chaos theory remains speculative, it illustrates how physics provides not just tools but conceptual frameworks for understanding cancer's complexity.

The Future: Personalized Physics-Based Treatments

The future of physics in cancer treatment looks increasingly sophisticated and personalized. Researchers are working on developing more compact particle accelerators that could make treatments like Flash radiotherapy more accessible ¹ . The ultimate goal is to make it possible for any hospital with radiotherapy equipment to provide Flash, potentially replacing existing conventional X-ray machines ¹ .

At the University of Pennsylvania, radiation oncologists are hoping to launch a clinical trial using proton Flash for patients with recurrent head and neck cancer ¹ . "These are patients who have few other options as their tumors are impossible to remove via surgery," says Alexander Lin, professor of radiation oncology. "We believe that proton Flash will be less toxic." ¹

Current Clinical Trials Exploring Flash Radiotherapy