Effect of dose rate on local control and complications in definitive irradiation of T1–2 squamous cell carcinomas of mobile tongue and floor of mouth with interstitial iridium-192

Constraints in the use of repair half times and mathematical modelling for the clinical application of HDR and PDR treatment schedules as an alternative for LDR brachytherapy

“…If LDR brachytherapy is used as a single modality in treating cancer of the oral cavity, the recommended dose is 65-70 Gy prescribed at a reference dose rate between 30-50 cGy/h [23,271, with as a consequence an overall treatment time limited to about 1 week, For such schedules an increase of local tumor control as com pared with conventional ERT alone or conventional ERT combined with an interstitial implant was observed, with an acceptable number of (late) normal tissue complications [3,7,18,[22][23][24]. However, due to variations in dose distribution, tumor size and irradiated volume, a straightforward comparison of LDR brachytherapy and conventional ERT is not possible.…”

Postoperative brachytherapy alone and combined postoperative radiotherapy and brachytherapy boost for squamous cell carcinoma of the oral cavity, with positive or close margins

“…4,23 When there is a positive or close margin at the primary site, a dose of 60 to 68 Gy is recommended. 4,8,10,24 For definitive BRT, Mazeron et al 25 and Simon et al 26 showed that for stage 1 -2 floor of mouth and mobile tongue, doses of 65 Gy or greater with intersource spaces of 1.2 to 1.4 cm result in a superior local control rate with low risk of complications.…”

“…that the incidence of minor and severe complications were 10% and 5%, respectively. To minimize necrosis, Mazeron et al, 25 in a series of 279 patients treated by BRT alone, recommended for stage 1 -2 carcinomas of the oral cavity, a dose rate of 0.3 to 0.5 Gy/hr. Pernot et al 35 reported, in a series of 1134 patients, prognostic factors for complications after definitive irradiation for cancers of the oral cavity and oropharynx.…”

How to Optimize Therapeutic Ratio in Brachytherapy of Head and Neck Squamous Cell Carcinoma?

“…The location of the primary tumour is also an important factor determining the likelihood of complications. Implanted floor of the mouth tumours are more frequently associated with necrosis, especially in bone, than tumours of other sites (13,16). No significant difference has been demonstrated in the occurrence of complications between patients with good or poor health status at the beginning of the treatment (13).…”

“…Dutreix (36) advocated the calculation of ERD with an h/i of 10 Gy and a Tr of 1 h for tumour and acute responding tissues and an h/i of 3 Gy and a Tr of 1.5 h for late-responding tissues. ERD was calculated for each patient implanted with 192 Ir for a T1-2 squamous cell carcinoma of the mobile tongue or floor of mouth (16). In this series it was found that ERD was significantly related to both recurrence and necrosis, that ERD could be calculated using a large range of h/i and Tr-values to predict both recurrence and risk of necrosis, and that ERD alone could not help to identify a group of patients with a low risk of both local recurrence and necrosis.…”