Effect of intersource spacing on local control and complications in brachytherapy of mobile tongue and floor of mouth.
From 1971 to 1988, 133 T1 and 141 T2 biopsy-proven squamous cell carcinomas of mobile tongue and floor of mouth were definitively managed by Iridium-192. Implantations were performed using either guide gutters or afterloading plastic catheters. The prescribed dose at the reference isodose (85% of the basal dose rate, Paris system) was 60-70 Gy. Total dose was not adjusted to dose rate or tumor volume. Results of the 274 implants have been analysed to look for a possible influence of intersource spacing on local control and necrosis. Follow up for patients free of local recurrence is 1-180 months with median of 35 months. The 274 tumors were divided into two groups according to intersource spacing: 9-14 mm (n = 204), and 15-20 mm (n = 70). At 5 years, the estimated local control (Kaplan Meier) was 86% and 76%; respectively (p = 0.13); the necrosis rate was 33% and 46%, respectively (p = 0.04). Multivariate analysis shows that dose and activity of wires were significantly related to local control, while only tumor site was predictive of necrosis; there was a non-statistically significant relationship between intersource spacing of wires and local control (p = 0.055). When considering only patients with oral tongue cancers, necrosis was significantly related to activity of wires (p = 0.013), and there was a non-significant trend to a relationship between necrosis and intersource spacing (p = 0.066) and tumor diameter (p = 0.065). For patients with floor of mouth cancer, none of these factors was significantly related to necrosis.(ABSTRACT TRUNCATED AT 250 WORDS)
Simon
J M
JM
Département de Cancérologie, Hôpital Henri Mondor, Créteil, France.
Mazeron
J J
JJ
Pohar
S
S
Le Péchoux
C
C
Crook
J M
JM
Grimard
L
L
Piedbois
P
P
Le Bourgeois
J P
JP
Pierquin
B
B
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001918:Brachytherapy / Q000009:adverse effects / Q000379:methods*; D002294:Carcinoma, Squamous Cell / Q000532:radiotherapy*; D005260:Female; D006801:Humans; D007496:Iridium Radioisotopes / Q000627:therapeutic use; D008297:Male; D008875:Middle Aged; D009060:Mouth Floor; D009062:Mouth Neoplasms / Q000532:radiotherapy*; D009336:Necrosis; D009364:Neoplasm Recurrence, Local; D014062:Tongue Neoplasms / Q000532:radiotherapy*; D017211:Treatment Failure
D007496:Iridium Radioisotopes