Predicting the local outcome of glottic squamous cell carcinoma after definitive radiation therapy: value of computed tomography-determined tumour parameters.
OBJECTIVE
The T-classification has shortcomings in the prediction of local outcome of glottic squamous cell carcinoma (SCC) treated by definitive radiation therapy. In this regard, the value of several CT-derived tumour parameters as predictors of local outcome was investigated.


METHODS
The pretreatment CT studies of 119 patients with glottic SCC (T1, n=61; T2, n=40; T3, n=14; T4, n=4) treated with curative intent by radiation therapy were reviewed for tumoral involvement of specific laryngeal anatomic subsites (including laryngeal cartilages). Tumour volume was calculated with the summation-of-areas technique. Actuarial (life-table) statistical analysis was done for each of the covariates; multivariate analysis was performed using the Cox proportional hazards model.


RESULTS
In the actuarial analysis tumour volume was significantly correlated with local recurrence rate (P=0.0062). Involvement of the cricoid cartilage (P=0.0052), anterior commissure (P=0.0203), subglottis (P=0.0481) and preepiglottic space (P=0.0134) and degree of involvement of the true vocal cord (P=0.0441) and paraglottic space at the level of the true vocal cord (P=0.0002) were also significantly correlated with local recurrence rate. In the multivariate analysis, only degree of involvement of the paraglottic space (at the level of the true vocal cord) (P=0.0001) and preepiglottic space (P=0.02) were found to be independent predictors of local recurrence. The T-category was significantly correlated with local outcome in the actuarial analysis (P=0.0001), but not in the multivariate analysis (P=0.5915).


CONCLUSIONS
Several CT-derived parameters are powerful predictors of local outcome in glottic cancer treated with radiation therapy; some of these parameters are stronger linked to the local control rate than the T-classification.
Hermans
R
R
Department of Radiology, University Hospitals, Leuven, Belgium.
Van den Bogaert
W
W
Rijnders
A
A
Doornaert
P
P
Baert
A L
AL
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002294:Carcinoma, Squamous Cell / Q000000981:diagnostic imaging / Q000473:pathology / Q000532:radiotherapy*; D005260:Female; D005544:Forecasting; D005931:Glottis / Q000000981:diagnostic imaging / Q000473:pathology / Q000528:radiation effects*; D006801:Humans; D007817:Laryngeal Cartilages / Q000000981:diagnostic imaging / Q000473:pathology; D007822:Laryngeal Neoplasms / Q000000981:diagnostic imaging / Q000473:pathology / Q000532:radiotherapy*; D007830:Larynx / Q000000981:diagnostic imaging / Q000473:pathology; D015993:Life Tables; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D009361:Neoplasm Invasiveness; D009364:Neoplasm Recurrence, Local / Q000473:pathology; D009367:Neoplasm Staging; D016016:Proportional Hazards Models; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome; D014827:Vocal Cords / Q000000981:diagnostic imaging / Q000473:pathology