Post-operative brachytherapy: a prognostic factor for local control in epidermoid carcinomas of the mouth floor

Results of postoperative interstitial brachytherapy of resectable floor of mouth tumors

PURPOSE

The purpose of this study was to describe the results of postoperative sole interstitial brachytherapy (BT) in patients with resectable floor of mouth tumors.

METHODS AND MATERIALS

Between January 1998 and December 2017, 44 patients with squamous cell histology, stage T1-3N0-1M0 floor of mouth tumor were treated by excision of the primary lesion with or without neck dissection followed by sole high-dose-rate tumor bed BT with an average dose of 22.7 Gy (10-45 Gy) using rigid metal needles (n = 14; 32%) or flexible plastic catheters (n = 30; 68%).

RESULTS

During a median followup time of 122 months for surviving patients, the probability of 5- and 10-year local and regional tumor control, overall survival (OS), and disease-specific survival (DSS) was 89% and 89%, 73% and 67%, 52% and 32%, 66% and 54%, respectively. In univariate analysis, lymphovascular invasion was a negative predictor of regional tumor control (p = 0.0062), DSS (p = 0.0056), and OS (p = 0.0325), whereas cervical recurrence was associated with worse DSS (p < 0.0001) and OS (p < 0.0001). The incidence of local Grade 1, 2, and 3 mucositis was 25%, 64%, and 11%, respectively. Grade 4 side effect, that is soft tissue necrosis occurred in four cases (9%).

CONCLUSIONS

Results of postoperative sole high-dose-rate BT of floor of mouth tumors are comparable with those reported with low-dose-rate BT, and this method could improve local tumor control and DSS compared with exclusive surgical treatment.

[Brachytherapy for head and neck cancers]

The main indications of the brachytherapy of head and neck cancers are the limited tumours of the lip, the nose, the oral cavity and the oropharynx. Nasopharynx tumours are nowadays treated by intensity-modulated radiotherapy. This technique can be exclusive, associated with external radiotherapy or postoperative. It can also be a salvage treatment for the second primaries in previously irradiated areas. If the low dose rate brachytherapy rules remain the reference, the pulse dose rate technique allows the prescription of the dose rate and the optimisation of the dose distribution. Results of high dose rate brachytherapy are now published. This paper reports the recommendations of the Gec-ESTRO, published in 2017, and takes into account the data of the historical low dose rate series, and is upgraded with the pulsed-dose rate and high dose rate series.

GEC-ESTRO ACROP recommendations for head & neck brachytherapy in squamous cell carcinomas: 1st update - Improvement by cross sectional imaging based treatment planning and stepping source technology

The Head and Neck Working Group of the GEC-ESTRO (Groupe Européen de Curiethérapie - European Society for Therapeutic Radiology and Oncology) published in 2009 the consensus recommendations for low-dose rate, pulsed-dose rate and high-dose rate brachytherapy in head & neck cancers. The use of brachytherapy in combination with external beam radiotherapy and/or surgery was also covered as well as the use of brachytherapy in previously irradiated patients. Given the developments in the field, these recommendations needed to be updated to reflect up-to-date knowledge. The present update does not repeat basic knowledge which was published in the first recommendation but covers in a general part developments in (1) dose and fractionation, (2) aspects of treatment selection for brachytherapy alone versus combined BT+EBRT and (3) quality assurance issues. Detailed expert committee opinion intends to help the clinical practice in lip-, oral cavity-, oropharynx-, nasopharynx-, and superficial cancers. Different aspects of adjuvant treatment techniques and their results are discussed, as well the possibilities of salvage brachytherapy applications.

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

BACKGROUND

Postoperative radiotherapy is necessary for squamous cell carcinoma (SCC) of the oral cavity with positive or close margins. The aim of the study is to define the indications of postoperative brachytherapy (BRT).

METHODS

From 1979 to 1993, 82 patients with positive or close margins had postoperative BRT (58 T1-2, 24 T3-4, 45 mobile tongue, 37 floor of mouth). Forty-six patients had combined radiotherapy (RT) with a mean dose of 48 Gy, and BRT boost with a mean dose of 24 Gy. Thirty-six patients had BRT alone with a mean dose of 60 Gy. BRT was performed with interstitial low dose rate Iridium 192.

RESULTS

Overall survival (OS), cause-specific survival (CSS), and local control (LC) at 5 years were, respectively, for T1-2/N0N- with BRT, 75%, 85%, and 88%,and with RT-BRT 70%, 92%, and 92%; for T1-2/N+ with RT-BRT, 44%, 67%, and 78%; for T3-4/N- with RT-BRT, 42%, 90%, and 80%; and for T3-4/N+ with RT-BRT, 22%, 43%, and 57%. Prognostic factors for OS, CSS, and LC were N+ (p </=.009), extracapsular spread (ECS+;p </=.000001), and T stage for LC only (p =.02). Prognostic factors for complications were a high number of wires with a cutoff at five wires (p =.008), a high dose rate with a cutoff at 0.57 Gy/hr (p =.01), and a high total dose (BRT + RT) with a cutoff at 71 Gy (p =.07).

CONCLUSIONS

BRT alone for SCC T1-2/N0N- is better than RT-BRT because, with equivalent results, it avoids the adverse events of postoperative RT (xerostomia) and permits the treatment of a second head and neck primary in nonirradiated tissue. The results for the T3-4/N- are acceptable with this approach (ie, RT-BRT) but may be improved for N+.

Mandibular osteoradionecrosis: clinical behaviour and diagnostic aspects

We have retrospectively studied 73 patients with mandibular osteoradionecrosis (ORN) following radiotherapy (high voltage external beam radiation alone, or combined with brachytherapy) ranging from 50 to 130 Gy (mean 76) with fields including the mandible. Based on this analysis we defined four distinctive stages: Stage 0: mucosal defects only; Stage I: radiological evidence of necrotic bone with intact mucosa; Stage II: positive radiographic findings with denuded bone intra-orally; Stage III: clinically exposed radionecrotic bone, verified by imaging techniques, along with skin fistulas and infection. The clinical features and characteristics of these stages are described, along with their clinical courses and outcome. The incompleteness of current ORN definitions, mainly emphasizing mucosal defects and bone exposure, and the need for a revised ORN classification is pointed out. Based on these observations and the insufficiency of previous definitions, we arrived at the following ORN definition: Radiological evidence of bone necrosis within the radiation field, where tumour recurrence has been excluded.

Postoperative brachytherapy alone for T1-2 N0 squamous cell carcinomas of the oral tongue and floor of mouth with close or positive margins

PURPOSE

To evaluate the efficacy of postoperative brachytherapy alone (brachy) for Stage T1-2 squamous cell carcinomas (SCC) of the floor of mouth (FM) and the oral tongue (OT) with close or positive margins.

METHODS AND MATERIALS

Between 1979 and 1993, 36 patients with T1-2 N0 (24 T1, 12 T2) OT (19), and FOM (17) SCC with close or positive margins following surgery underwent postoperative brachy. Mean patient age was 56 years (range 37-81) and sex ratio was 3.5:1 male:female. Mean surgery to brachy interval was 36 days (range 16-68). The technique used was interstitial Iridium-192 ((192)Ir) brachytherapy with plastic tubes and manual afterloading. Mean total dose was 60 Gy (range 50-67.4) at a mean dose rate of 0.64 Gy/h (range 0.32-0.94). Mean patient follow-up was 80 months.

RESULTS

The 5-year actuarial overall and cause-specific survivals of the entire group were 75% and 85%, respectively. The local control was 88.5% at 2 years, with a plateau apparent after 23 months. Of the 4 local relapses, 2 were salvaged with surgery and external beam radiotherapy (EBR). No tumor or treatment factors, including tumor size, margin status, disease site, or radiation dose, were correlated with local control. The 2 head and neck second primaries underwent curative treatment on nonirradiated tissue. One patient developed a grade 3 sequelae (bone and soft tissue necrosis). Grade 2-3 chronic sequelae were seen in 7 of 17 and 3 of 19 FOM and OT tumors, respectively (p = 0.09).

CONCLUSION

Postoperative brachy is a promising approach in T1-2 N0 OT and FOM SCC with close or positive margins. This approach is associated with high rate of locoregional control and low risk of chronic sequelae, obviates major surgery, avoids potential sequelae of EBR (xerostomia, dysgueusia, fibrosis), and avoids treatment of second head and neck primary on nonirradiated tissues.