Freedman, G.M., Anderson, P.R., Li, J., Jinsheng. L., Eisenberg, D.F., Hanlon, A.L., . . . Nicolaou, N. (2006). Intensity modulated radiation therapy (IMRT) decreases acute skin toxicity for women receiving radiation for breast cancer. American Journal of Clinical Oncology, 29, 66–70.

To determine the incidence and severity of acute skin toxicity with IMRT compared to conventional RT

Women treated with breast conserving surgery and IMRT were matched one to one with historical controls based on bra size and chest wall separation. Maximum recorded skin toxicity during six weeks of RT was compared between the two groups using Chi-squared analysis or Fisher-exact tests. Cases were grouped for analysis by bra size.

• The study sample was comprised of 133 female cases, with 73 IMRT and 60 conventional historical controls cases.
• All patients had breast cancer in stage 0, I, or II.
• Breast dose ranged from 46–50 Gy, with a median of 46; the total dose ranged from 50–64 Gy, with a median of 60 in IMRT and 64 in conventional.

The study took place at Fox Chase Cancer Center.

The study used a prospective comparison with matched historical controls design.

Acute skin toxicity was scored using the National Cancer Institute (NCI) common terminology criteria (CTC) for acute radiation dermatitis by the physician or nurse weekly during treatment. Scores given to evaluate erythema were grade 1 for mild and grade two for moderate. Scores given for desquamation were grade 1 for dry and grade 2 or 3 for moist. Additional variables included in analysis were chest wall separation, total energy megavoltage, use and timing of chemotherapy, use and timing of tamoxifen, and tumor stage.

The degree of desquamation was greater for conventional patients (p = 0.0001). In the IMRT group, 21% had grade 2, compared to 38% in the RT group. Grade 1 desquamation was higher in the IMRT group (37% IMRT, 10% RT). No patient had grade 3 desquamation. There were no differences between the two groups in CTC or erythema scores. Subgroup analysis showed that the incidence and severity of desquamation by bra size was significantly lower in the IMRT group for small and large breast sizes (p < 0.04) but not for medium sizes. Use of IMRT (p = 0.0011) and breast size (p < 0.0001) were the only significant predictors for having moist desquamation.

IMRT was associated with reduced incidence and severity of desquamation.

Although CTV was found to be a significant predictive variable, it was not included in the stepwise regression analysis.