A comparison of two scoring systems for late radiation toxicity in patients after radiotherapy for head and neck cancer

Abstract

Background

The EORTC/RTOG late effects classification has been used for many years and covers nearly all organs and tissues, which may develop late radiation injuries. Dische developed a scoring system for radiation toxicity in which each clinical sign or symptom, that is characteristic for disturbance of function in an irradiated organ, is given scores for severity individually. EORTC and RTOG formed working groups to up-date their systems, for the recording of late injury to normal tissues, to be used in future clinical trials. The resulting system is called LENT-SOMA (1993).

Aim

In preparation for the introduction of the LENT-SOMA scale into clinical practice at the Centre of Oncology-Institute in Gliwice, we followed a sizeable cohort of patients using two scoring systems for the assessment of delayed radiation toxicity at each follow-up examination which took place every 6 months for up to 5 years after curative radiotherapy for head and neck cancer.

Materials/Methods

The analysed material comprised of 113 patients with oral cavity, pharyngeal or supraglottic cancer (T2-4N0-1) irradiated by conventional methods (18 patients), continuous accelerated irradiation (CAIR) (52 patients) or concomitant boost (CB) (43 patients). Total dose was in the range of 66–74 Gy. Delayed radiation toxicity was evaluated by two classification systems, those of Dische and LENT-SOMA, in the mucosal membranes, skin, larynx, salivary glands and spinal cord every 6 months after completion of radiotherapy treatment. The values in every scale were normalised (as a proportion of the maximum intensity for all symptoms) which permitted statistical comparison of the scales by use of the Wilcoxon test.

Results

Analysis of all materials indicated a difference in the intensity of late radiation toxicity as estimated by the Dische and LENT-SOMA scales. The intensity of delayed radiation toxicity in the normalised Dische scale, for mucosal membranes and for skin, had higher values than observed in the LENT-SOMA system for the majority of examined patients. In the case of the larynx and salivary glands, the opposite situation was noted. The extent of conformity between normalised scales was evaluated in the case of the spinal cord.

Conclusions

The scoring systems of Dische and LENT-SOMA can not be interchangeably used, in clinical practice, for the estimation of delayed radiation toxicity in tissues of the head and neck region. The sensitivity of the scoring systems is similar only for the evaluation of radiation reactions in spinal cord.