Tumour volume: implications in T2/T3 glottic/supraglottic squamous cell carcinoma

In this study, tumour volume was investigated to determine if it predicts locoregional control of T2/T3 glottic/supraglottic laryngeal carcinoma treated with radiotherapy or surgery. The effect of radiotherapy dosage was also assessed in those patients treated with primary radiotherapy. The ability to identify a subset of patients suitable for primary radiotherapy and, hence, voice preservation based on pretreatment computerized axial tomography (CT) would be valuable.

The charts of 55 patients referred to the London Regional Cancer Centre (LRCC) between 1988 to 1994 were reviewed. Each presented with a previously untreated T2 or T3 squamous cell carcinoma (SCC) of either the glottic or supraglottic larynx. Tumour volume was calculated from pretreatment CT scans by observers unaware of the clinical data associated with each radiograph. Wilcoxon t test and univariate and multivariate Cox regression analyses were performed.

Mean tumour volume differed between those patients treated with radiotherapy and those treated surgically (4.5 cm3 and 11 cm3, respectively; p < .01). Mean tumour volume also differed between T2 and T3 tumours in the primary radiotherapy group (3.8 cm3 and 9.3 cm3, respectively; p < .01). Tumour volume > 4.0 cm3 was a significant predicator of local failure in T2 laryngeal tumours treated with radiotherapy (p < .05). This volume effect was not abolished with increasing radiotherapy dosage. Tumour volume was not a significant predictor of local control in the T3 tumours treated with radiotherapy or when all tumours, irrespective of T stage, that were treated with radiotherapy were considered together. There was no similar volume effect found in the surgical group.

Tumour volume > 4 cm3 predicts local failure in T2 laryngeal tumours treated with radiotherapy regardless of radiotherapy dosage. This volume effect is not seen in those tumours treated with surgery. Inclusion of tumour volume data may eventually augment our current classification system.