Improved Cosmesis in Early Breast Cancer Using Conformal Radiotherapy
Authors: Brian D. Kavanagh, Rachel Rabinovitch, Najeeb Mohideen
Journal: Journal of Clinical Oncology (2013)

In the article that accompanies this editorial, Mukesh et al from Cambridge University report a randomized study comparing two external-beam radiotherapy techniques for early-stage breast cancer. The central conclusion is that cosmetic outcome is improved by adding a layer of technologic sophistication to the most basic technique for whole-breast radiotherapy. The authors are to be congratulated for successfully executing the study; however, like most good research, the article raises at least as many questions as it answers. Before we can discuss the clinical results of the study, we first need to acknowledge that there are differences in the terminology used to describe the same treatment procedures in different countries. This nomenclature issue is particularly important in the United States, where there can be substantial financial implications. Mukesh et al correctly note that the term intensity-modulated radiotherapy (IMRT) has been applied loosely at times to cover a wide range of techniques. These range from simple modifications that slant the cross-sectional profile of the generally flat beam coming out of the linear accelerator to yield a uniform gradient of internal dose to highly complex configurations of rotating gantries with shape-shifting multileaf collimators and variable photon fluence rates that texturize the beam to paint an undulating internal dose distribution. The latter complex approach allows coverage, for example, of a base-of-tongue primary cancer and regional draining lymph nodes with a high dose, while sparing sensitive normal structures such as the parotid gland and spinal cord. In one of its Choosing Wisely campaign recommendations, the American Society for Radiation Oncology (ASTRO) advises, “Don’t routinely use intensity modulated radiotherapy (IMRT) to deliver whole breast radiotherapy as part of breast conservation therapy.” At first glance this statement seems to conflict with the results of the Cambridge study, but on closer analysis the disconnect is reconciled by considering differences in IMRT definitions. What Mukesh et al label as “simple IMRT” is not properly considered IMRT in the United States, at least not in the sense of being billable according to the Common Procedural Terminology (CPT) code for IMRT. Instead, what is described in the article, in CPT-speak, is a method of threedimensional (3D) conformal radiation therapy, here accomplished using an open tangential beam augmented by several additional fieldin-field segments. That we are here wallowing in the murky morass of CPT billing semantics is not a criticism of Mukesh et al as much as a concession that the CPT definition of IMRT is ambiguous and often misunderstood. For the record, in other studies in which investigators have compared so-called IMRT with a simpler technique of breast radiotherapy, the same terminology confusion has occurred. For example, Pignol et al similarly referred to a field-in-field 3D conformal RT technique as IMRT in a study published several years ago in Journal of Clinical Oncology. The problem with mistakenly referring to a form of 3D conformal RT as IMRT is that some might misinterpret the study to mean that it is appropriate to bill for IMRT in this setting, which would substantially escalate costs. Fortunately, parsing help is on the way through proposed revisions of the definitions of IMRT and certain other billing codes that should help to avoid this confusion. To nonradiation oncologists, it might be expected that the type of trial executed by the Cambridge group should be commonplace. How hard can it be to compare older technology with newer technology? It is important to realize that it was around 1990 that software capable of integrating computed tomography scan–based anatomic information with the choice of linear accelerator beam direction and aperture design appeared—in effect, it was the dawn of the era of 3D treatment planning and delivery. Since that epochal advance, innumerable individual software and hardware inventions have expedited stepwise evolution toward highly refined methods of depositing ionizing radiation therapy inside a patient, all geared toward maximizing the therapeutic ratio, a semiquantitative index conceived as the chance of providing benefit (eg, tumor control) divided by the chance of causing harm (ie, adverse effects), although rarely if ever explicitly calculated. The myriad component contributions that have enabled progress include the development of multileaf collimators, computerized dose calculation algorithms accounting for tissue electron density, and image guidance software and hardware that facilitate target relocalization at the time of treatment. And these are just a few of the thousand small steps in a journey of many miles that cannot all be tested separately as to whether they are the best choice in the quest for excellence. In most cases they have to be accepted at face value as intrinsically better on a res ipsa loquitur basis, because there are not enough resources available to perform a randomized study at each point along the way. Nevertheless, we must periodically pause to gauge where we are and where we should go, as the Cambridge group has done. At the very least, it can be reassuring when what is supposed to matter actually does matter. Here, an adjustment in the treatment plan that avoided JOURNAL OF CLINICAL ONCOLOGY E D I T O R I A L VOLUME 31 NUMBER 36 DECEMBER 2