Epidermoid carcinomas of the floor of mouth treated by exclusive irradiation: statistical study of a series of 207 cases.
OBJECTIVE
Our aim was to study the results and the complications of this series of 207 patients treated from 1976 to 1992 and to compare them with the results of the literature.


METHODS
The treatment consisted of a combination of external beam irradiation (EBI) (to the tumor and the node areas) and complementary brachytherapy to the primary tumor in 105 cases. In 102 cases, brachytherapy only was delivered to the tumor with or without neck dissection of the node areas. The brachytherapy was performed mostly with the hairpin technique in the beginning (in 61 cases) and subsequently the plastic tube technique with iridium wires. The dosimetry followed the Paris system rules. There were 41% T1, 48% T2, 8% T3, 2% T4 and 1% Tx with 83% N0, 12% N1, 3% N2, 2% N3. Ninety-one percent of patients were male and 9% were female.


RESULTS
The local control at 5 years is 97, 72 and 51%, respectively, for T1, T2, T3. The specific survival (without the patients dead of intercurrent disease or second cancer) was 88, 47 and 36%, and the overall survival at 5 years was 71, 42 and 35%. Of note, approximately one third of patients died of intercurrent disease or second cancers (70 patients = 34%). Significant factors that can influence the results are: for local control, the size of the lesion T1/T2/T3 (p < 0.0001); for the locoregional control, the absence of node involvement. The following factors are not significant: age and sex (age significant for survival). The significant treatment factors are the safety margin (p < 0.0003), brachytherapy only on T for T2N0 (p = 0.01). A total duration of treatment of less than 50 days is also significant. The spacing and the total dose (higher dose for large tumors) were not found to be significant. The complications were classified into four grades: grade 1, 17% (median healing, 2 months for soft tissue complications and 5 months for bone complications); grade 2, 12%; grade 3, 6% (frequently requiring surgical resection); grade 4, 0.5% (death, one case). In this series, for the complications, the dose rate, the spacing and the total dose were found not to be significant.


CONCLUSIONS
Carcinomas of the floor of mouth treated by exclusive irradiation have a rather good prognosis and the number of grade 2 and 3 complications remains acceptable. Exclusive brachytherapy is preferable to the combination of EBI plus brachytherapy for T1T2N0.
D001918:Brachytherapy / Q000009:adverse effects; D002294:Carcinoma, Squamous Cell / Q000401:mortality / Q000532:radiotherapy* / Q000601:surgery; D003037:Cobalt Radioisotopes / Q000627:therapeutic use*; D003131:Combined Modality Therapy; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009060:Mouth Floor; D009062:Mouth Neoplasms / Q000401:mortality / Q000532:radiotherapy* / Q000601:surgery; D015999:Multivariate Analysis; D037981:Neck Dissection; D009364:Neoplasm Recurrence, Local / Q000401:mortality; D016609:Neoplasms, Second Primary / Q000401:mortality; D011379:Prognosis; D011867:Radioisotope Teletherapy / Q000009:adverse effects; D011879:Radiotherapy Dosage; D016019:Survival Analysis; D013997:Time Factors
D003037:Cobalt Radioisotopes