Breast IMRT reduces acute radiation-induced dermatitis

Using intensity-modulated radiation therapy for breast cancer patients after lumpectomy can reduce the incidence of acute dermatitis, compared with traditional whole-breast radiotherapy, reported Jean-Philippe Pignol, MD, of Sunnybrook Health Sciences Centre, Toronto, and colleagues.

In this multicenter, phase III, double-blinded clinical trial, 358 women with early-stage breast cancer were randomized to receive IMRT or standard radiation therapy with wedge compensation. In both cases, the dose was 50 Gy in 25 fractions. A boost dose of 16 Gy was given when appropriate.

“The two treatment arms differed by the missing tissue compensation method (2D vs 3D) used to account for variations in breast shape,” Dr. Pignol and his colleagues wrote. “The standard arm used a tungsten wedge inserted in the beam path and the experimental arm used breast IMRT” (J Clin Oncol 26:2085-2092, 2008).

Improved dose distribution

Among the 331 patients analyzed, breast IMRT significantly improved the dose distribution, compared with standard radiation, which translated into a significantly reduced occurrence of moist desquamation (31.2% vs 47.8% for standard radiation, P = .002).

Moist desquamation was associated with a higher pain score and reduced quality of life. In multivariate analysis, smaller breast size was also significantly associated wtih a decreased risk of moist desquamation.

There was a trend toward fewer grade 3-4 acute skin reactions in the IMRT arm, with an absolute reduction of 9.5%.

Commentary

The clinical implications of the Canadian trial are manifold, Bruce Haffty, MD, of the Cancer Institute of New Jersey, and coauthors wrote in an accompanying editorial.

In addition to decreased acute toxicity, they wrote, IMRT could lead to decreased long-term skin toxicity. Further, reduced toxicity from radiation therapy could encourage researchers to re-examine the use of concurrent chemoradiotherapy in select patients. Finally, the improved homogeneity achieved with IMRT could lead to studies of other novel accelerated fractionation schemes.

They noted that financial hurdles to the widespread acceptance of breast IMRT still remain. The current technical charges for IMRT planning and delivery are significantly higher than for conventional treatment, leading insurers to resist covering the technique.

Even though breast IMRT is much less complex than IMRT of other tumor sites, such as the prostate and head and neck, there is only one technical charge code for IMRT, they pointed out.

The commentators suggested the charge code should be modified “to more appropriately reflect the complexity of the treatment delivered, with perhaps two or three separate levels, with more clearly defined guidelines for coding.”