The history of radiation oncology.

When the SMA was founded in 1906, the discoveries of x-rays by Rontgen in 1895, and radioactivity by Becquerel in 1896, were virtually current events. That first era for radiation oncology was one of curiosity, experimentation, and empiricism. Early physicians merely applied exposure to radiation to "see what happened" and based their clinical practice on the observations. Although ignorant of the mechanism of action, doctors reported cases of the control or regression of cancers due to radiation exposure. Scarcely bridled enthusiasm held promise that these new agents would be the answer to the cancer problem. Mixed with the laudable results, however, were horrid tragedies. Lacking comprehension of dose phenomenon and fundamental radiation biology principles, doctors discovered radiation's delayed harmful effects in conjunction with the awareness of its usefulness. Perhaps most tragically, it was early physicians and scientists who suffered many injuries and death.

Early optimism was replaced by a profound pessimism for the medical role of radiation. Just as medicine at-large was becoming less empiric and more scientific, so radiation use would change during the 1920s and 30s. The death and disease from early experimentation led to the first laboratory and animal experiments in radiation biology, which in many ways gave birth to our understanding of cancer biology. This first rise of "radiation biology" prompted more uniform ideas of cancer treatment.

After the first biologic era, there followed a time devoted to improvements in physics. Burgeoning knowledge triggered by fundamental thinkers was coupled with grand efforts like the Manhattan project. Physics innovation brought reliable megavoltage energy with the development of man-made cobalt and early linear accelerators, allowing the first meaningful way to address deep structures in the body.

In the 1960s, chemotherapy development brought a new tool and a new sort of specialist to the world of cancer management. This change prompted an adaptive reaction to match the level of training and expertise by promoting the first dedicated radiotherapy residencies. A separate academic and scientific specialty of radiation oncology arose, which now shares little in common with its ancestry in diagnostic radiology, save similar sounding names.

Enthusiasm for the first chemotherapy agents in this era echoed the enthusiasm for radiation from a half-century before. It became commonplace to read or to hear prophecies of the impending demise of x-ray therapy. Repeated often, these predictions took on the aura of common knowledge, yet they have proven both false and short-sighted. Despite advances in medical oncology, only a minority of cancers can be cured with drugs. Chemotherapy's prime role continues to be in adjunct to appropriate surgery and radiotherapy. Modern clinical trials confirm that better chemotherapy has actually increased the role and importance of radiotherapy, such that more patients than ever before are receiving and benefiting from radiation treatment. In the United States, approximately 60% of people diagnosed with cancer will have radiotherapy at some point in their care. Population models suggest that radiation cures about three times as many people as does chemotherapy. (1) We see, however, that more than one-third of definitive radiotherapy patients will experience persistent or recurrent local disease. The strong implication remains that higher doses of radiation delivered more effectively can continue to impact future cancer control rates.

Much of the increased role for radiation can be attributed to the enhanced ability to see and target tumors deep within the body. This Renaissance, ignited by better imaging and fueled by better computers, found radiation oncologists involved in addressing diseases that had formerly been outside their provenance. Until the 1980s, radiation oncology textbooks were typically written in a "this is how I do it" cookbook fashion. Cartoon diagrams of typical treatment fields directed physicians to reproduce those diagrams for treating actual patients. We now can hardly imagine pursuing our field without the revealing roadmaps provided by CT and MRI scans. This enhanced intelligence was further aided by the advent of computers, which made incredibly complex physics and dose calculations less onerous. No longer tethered to a cookbook approach to the care of patients, innovation followed, which allowed radiation oncologists to deliver individualized treatment.

While the evolution of computers and machines is yet on the ascendancy, our current era is better characterized as a second great era for cancer biology. The unfolding of the secrets of DNA and the cell cycle and our increasing ability to explain the most fundamental aspects of molecular and cellular function have altered the clinical face of cancer care. We have been humbled to learn just how exceedingly complex this set of diseases can be. The naive belief that a singular "cure" for cancer would be identified has given way to the reality of the need for painstaking work and basic research. Even so, translational research is allowing for better staging, even better imaging, and an individualized assessment of risks and benefits of therapy. Radiotherapy is being combined in innovative and interesting ways as we gain a clearer view of the interface of physics, chemistry, and biology.

This tide of faster computers, wonder gadgets, and breathtaking imaging has created the impression for some that a radiation oncologist's practice is more akin to a sophisticated video game than to the practice of medicine. True, bright medical minds are first attracted to the field by its engaging technology; however, our recent era has seen a climate of "high touch" arise to sit alongside the "high tech." As one of the more highly sought medical specialties, the newest generation of radiation oncology scientists and clinicians are drawn from high-achieving ranks and are better trained as doctors, first, and technicians, second. Radiation oncologists are now more apt to see themselves as skilled consultant clinicians who are trained and capable of managing many aspects of a patient's care. They are increasingly independent advocates for a data-driven approach to cancer care, believing that science will continue to confirm the vital role of radiation in medicine.

Reference

1. Djulbegovic B, Sullivan DM, eds. Decision Making in Oncology: Evidenced-Based Management. Philadelphia, Churchill-Livingstone, 1997.

We are apt to forget that children watch examples better than they
listen to preaching.
--Roy L. Smith

Kyle Colvett, MD

From Appalachian Radiation Oncology Associates, Johnson City, TN.

Reprint requests to Kyle Colvett, MD, Johnson City Medical Center, 400 North State of Franklin Road, Johnson City, TN 37604. Email: [e-mail]