Increasing the rate of late toxicity by changing the score? A comparison of RTOG/EORTC and LENT/SOMA scores.

Purpose: The Radiation Therapy Oncology Group (RTOG) and Late Effects Normal Tissue Task Force subjective, objective, management, and analytic (LENT/SOMA) scores were compared in a group of breast cancer patients. The impact of the classification system on grading late effects was evaluated.

Materials And Methods: Telangiectasia, skin pigmentation, and fibrosis were scored according to both LENT/SOMA and RTOG criteria. The results were compared with respect to up- or downgrading and correlated (Spearman's rho). Other side effects were recorded using LENT/SOMA criteria. Interobserver variability was calculated with Cohen's kappa. Two hundred fifty-nine subsequent relapse-free patients who underwent breast-conserving therapy between 1981 and 1995 were examined. The median dose of radiotherapy to the breast was 55 Gy. Adjuvant chemotherapy was given to 31 patients and tamoxifen to 52 patients. The median follow-up was 8 years. RTOG skin and s.c. tissue scales and LENT/SOMA breast and pigmentation scales were used. Two doctors examined 45 patients jointly.

Results: Of all patients, 20% had telangiectasia, 22% pigmentation, 43% fibrosis, 4% breast edema, 77% retraction/atrophy, and 54% pain. In comparison, when LENT/SOMA criteria were used, telangiectasia and pigmentation were upgraded in 34% and 36%, respectively, and telangiectasia was downgraded in 45%. Fibrosis correlated well (Spearman's rho 0.78, p = 0.01). An additional 356 side effects, mainly retraction/atrophy were observed in 226 patients using LENT/SOMA criteria. Interobserver variability was similar for both classification systems and ranged from Cohen's kappa 0.3 (retraction) to 0.91 (telangiectasia).

Conclusions: LENT/SOMA criteria seem to be the better tool in grading and recording late radiation toxicity compared with the RTOG scale. There was some upgrading with the RTOG score when skin toxicity is evaluated. In contrast, fibrosis scores correlated very well. Adjustments of the LENT/SOMA scoring system should be considered to standardize reporting of late radiation morbidity.