High dose rate brachytherapy using molds after chemoradiotherapy for oral cavity cancer

Oral Cavity Squamous Cell Carcinoma: Review of Pathology, Diagnosis, and Management

Squamous cell carcinoma of the oral cavity presents a significant global health burden, primarily due to risk factors such as tobacco smoking, smokeless tobacco use, heavy alcohol consumption, and betel quid chewing. Common clinical manifestations of oral cavity cancer include visible lesions and sores, often accompanied by pain in advanced stages. Diagnosis relies on a comprehensive assessment involving detailed history, physical examination, and biopsy. Ancillary imaging studies and functional evaluations aid in accurate staging and facilitate treatment planning. Prognostic information is obtained from histopathological factors, such as tumor grade, depth of invasion, lymphovascular invasion, and perineural invasion. Notably, lymph node metastasis, found in approximately half of the patients, carries significant prognostic implications. Effective management necessitates a multidisciplinary approach to optimize patient outcomes. Surgical resection is the backbone of treatment, aimed at complete tumor removal while preserving functional outcomes. Adjuvant therapies, including radiation and chemotherapy, are tailored according to pathological factors. Further work in risk stratification and treatment is necessary to optimize outcomes in squamous cell carcinoma of the oral cavity.

Evaluation of patients with oral squamous cell carcinoma treated by radical irradiation with mold radiotherapy using a customized device: a retrospective clinical study

Background

It is very important to determine the indication of mold radiotherapy for the radical treatment of oral cancer. We investigated eight patients with oral squamous cell carcinoma who were treated by radical irradiation with mold radiotherapy using a customized device.

Methods

The subject is a case of curable superficial oral cancer of a few millimeters, or cancer of a size that can be cured by the placement of the radiation source. Of the eight patients, six were male and two were female, aged 64–93 years (mean, 78.9 years; median, 73.5 years). The primary sites were the buccal mucosa in three cases, gingiva in two cases, and floor of the mouth, soft palate, and lower lip in one case each. Five cases were in the T1 stage, and the remaining three cases were in T2. With respect to thickness, seven cases were of the superficial type and could not be detected by magnetic resonance imaging or computed tomography, and the remaining case showed a tumor thickness of 7.5 mm. All cases were diagnosed as squamous cell carcinoma by biopsy. Radical irradiation using mold radiotherapy was planned for all eight patients. Irradiation was delivered in 9–10 sessions, with a total dose of 45–50 Gy.

Results

Complete response was attained in six of the eight patients and partial response was observed in two patients, requiring additional treatment.

Conclusion

Since all patients with complete response had superficial cancers, we hypothesized that superficial cancers of the oral cavity with thicknesses of few millimeters could be indicated for mold irradiation. This method can be applied in complicated cases and older patients in whom surgery or chemotherapy may not be feasible. We believe that the results of our clinical studies will be of great help in choosing this method.

Individual 3-dimensional printed mold for treating hard palate carcinoma with brachytherapy: A clinical report

This clinical report describes the use of a 3-dimensional (3D) printer to create an individual mold for delivering high-dose-rate interventional radiotherapy for hard palate cancer. The maxillary teeth and palate were scanned with an intraoral scanner (3Shape TRIOS 3). The scan was transformed into a mesh using the standard tessellation language (STL) format and aligned with Digital Imaging and Communications in Medicine (DICOM) computed tomography (CT) images using free Blue Sky Plan 4 planning software. A mold was generated by tracing a guideline around the gingival margins of the maxillary teeth and palate on the scan mesh in accordance with established parameters. All data were imported into computer-aided design (CAD) software. For this patient, 3 parallel 2.2-mm-diameter ducts were placed 10 mm from each other in the mold mesh. A CT scan of the patient's mouth with the mold in place was used for treatment planning. Treatment was delivered by means of microSelectron digital afterloading.

High-dose-rate brachytherapy in severe trismus: Making it happen!

Brachytherapy has been widely employed as a salvage or adjuvant modality in localized early and/or recurrent lesions. In recent years, advances in brachytherapy techniques have helped to achieve better loco-regional disease control and higher survival rates at the cost of limited morbidity. This is mainly owing to the development of technologically advanced three-dimensional computer planning systems and treatment delivery techniques. Low-dose-rate brachytherapy has been substituted by high-dose-rate and pulsed-dose-rate techniques, which allow better dose optimization. Inter-disciplinary approach results in fabrication of customized intra-oral surface mould, which allows accurate dose delivery, excellent dose distribution, and is less time-consuming. However, fabrication of surface mould becomes extremely challenging when intra-oral anatomic factors are unfavorable. We present a report on the management of a previously-irradiated completely edentulous patient with severe trismus for whom high-dose-rate surface mould brachytherapy had been prescribed. A unique, reliable, and practical solution has been presented based firmly on the scientific knowledge of contemporary implant dentistry.

Dosimetric analysis and clinical outcomes in CT-based mould brachytherapy in early oral cancers in patients unfit for surgery

Purpose

Brachytherapy in the oral cavity is an important alternative to conventional treatment, and provides a high localized dose and short overall treatment time. A rapid fall of dose beyond radioactive source makes it possible for increased tumour control and sparing surrounding tissue, while short overall treatment duration reduces risk of tumour repopulation. Moulds are fabricated to hold the catheters in position as closely as possible to tumour surface to provide adequate dose coverage of tumour volume and increase distance to other normal surrounding structures. Image based planning and dose optimisation help in better defining target volume and dose coverage.

Material and methods

A retrospective analysis of patients of early squamous cell carcinomas of lip and buccal mucosa from September 2011 to June 2014 to study response to mould brachytherapy. Double plane moulds were prepared for all lip cancer cases and single plane for buccal mucosa cases. Patients are being followed up till disease recurrence. In this study evaluation was done of the technique used, planning details, response to therapy, and reactions encountered.

Results

Nine patients treated by mould therapy were reviewed; seven cases were of lip and two of buccal mucosal cancers. Dose delivered ranged from 12.5-48 Gy in fraction sizes of 2.5-3.5 Gy. Equivalent dose in 2 Gy fractions (EQD2) ranged from 18-64 Gy. Maximum dose to organs at risk (OAR) was 91% of prescribed dose. Local mucositis was only reaction in all cases, which resolved in 3-6 weeks. Median follow-up was 19 months. Eight out of nine patients are in remission at a minimum of 7 months (1 case, rest over 14 months) post therapy and only patient had nodal recurrence at 18 months.

Conclusions

Mould therapy is an effective treatment method for selected early and superficial squamous cell carcinomas of the oral cavity, although indications are limited.

Cancer of the gingiva

Cancer of the gingiva is a rare disease in the Western World. It most commonly affects elderly population. Because of its rarity, the reporting on the disease is sparse and often grouped with other subsites of oral cancer, which makes conclusions difficult to interpret. The aim of this paper is to review the literature on gingival cancer as a specific subsite of oral cancer and report on published prognostic factors as well as treatment of local and regional disease. We also present differences between gingival cancer subgroups, mandibular and maxillary gingival cancer. In addition, both surgical and oncological treatments are reviewed. It seems that surgery is the preferred initial treatment approach for the majority of patients with gingival cancer, although adjuvant radiation, with or without chemotherapy, is commonly recommended to increase locoregional control.

A unique approach to high-dose-rate vaginal mold brachytherapy of gynecologic malignancies

PURPOSE

Patients with cervical and vaginal cancer sometimes have a less straightforward approach for choice of brachytherapy treatment owing to the tumor's location and clinical presentation. The staff at Royal Brisbane & Women's Hospital in Queensland, Australia, is trying to solve this problem by the use of an old technique in a new approach called vaginal molds. With a patient-specific vaginal mold, the appearance of the applicator and the dose distribution can be customized to provide an optimal treatment for each patient.

METHODS AND MATERIALS

The technique used at the Royal Brisbane & Women's Hospital uses a flexible two-part putty, moulded to the shape of the vagina, in which standard catheters (flexible implant tubes) are incorporated, in a pattern designed to permit a dose distribution more conformal to the target volume.

RESULTS

The presented technique is efficient and improves the accuracy of a homogeneous target cover and sparing of organs at risk for vaginal mold brachytherapy treatments at our institution.

CONCLUSION

This technique offers a customizable option when traditional cylindrical- or dome-type applicators cannot be used, or provide inadequate dose coverage. Molds to match the patient anatomy can be created quickly, while allowing flexibility in positioning of catheters to achieve the desired dose distribution.

Oral cancer: Current role of radiotherapy and chemotherapy

The term oral cavity cancer (OSCC) constitutes cancers of the mucosal surfaces of the lips, floor of mouth, oral tongue, buccal mucosa, lower and upper gingiva, hard palate and retromolar trigone. Treatment approaches for OSCC include single management with surgery, radiotherapy [external beam radiotherapy (EBRT) and/or brachytherapy], as well as adjuvant systemic therapy (chemotherapy and/or target agents); various combinations of these modalities may also be used depending on the disease presentation and pathological findings. The selection of sole or combined modality is based on various considerations that include disease control probability, the anticipated functional and cosmetic outcomes, tumor resectability, patient general condition, and availability of resources and expertise. For resectable OSCC, the mainstay of treatment is surgery, though same practitioners may advocate for the use of radiotherapy alone in selected "early" disease presentations or combined with chemotherapy in more locally advanced stage disease. In general, the latter is more commonly reserved for cases where surgery may be problematic. Thus, primary radiotherapy ± chemotherapy is usually reserved for patients unable to tolerate or who are otherwise unsuited for surgery. On the other hand, brachytherapy may be considered as a sole modality for early small primary tumor. It also has a role as an adjuvant to surgery in the setting of inadequate pathologically assessed resection margins, as does postoperative external beam radiotherapy ± chemotherapy, which is usually reserved for those with unfavorable pathological features. Brachytherapy can also be especially useful in the re-irradiation setting for persistent or recurrent disease or for a second primary arising within a previous radiation field. Biological agents targeting the epithelial growth factor receptor (EGFR) have emerged as a potential modality in combination with radiotherapy or chemoradiotherapy and are currently under evaluation in clinical trials.

High dose rate brachytherapy for oral cancer

Brachytherapy results in better dose distribution compared with other treatments because of steep dose reduction in the surrounding normal tissues. Excellent local control rates and acceptable side effects have been demonstrated with brachytherapy as a sole treatment modality, a postoperative method, and a method of reirradiation. Low-dose-rate (LDR) brachytherapy has been employed worldwide for its superior outcome. With the advent of technology, high-dose-rate (HDR) brachytherapy has enabled health care providers to avoid radiation exposure. This therapy has been used for treating many types of cancer such as gynecological cancer, breast cancer, and prostate cancer. However, LDR and pulsed-dose-rate interstitial brachytherapies have been mainstays for head and neck cancer. HDR brachytherapy has not become widely used in the radiotherapy community for treating head and neck cancer because of lack of experience and biological concerns. On the other hand, because HDR brachytherapy is less time-consuming, treatment can occasionally be administered on an outpatient basis. For the convenience and safety of patients and medical staff, HDR brachytherapy should be explored. To enhance the role of this therapy in treatment of head and neck lesions, we have reviewed its outcomes with oral cancer, including Phase I/II to Phase III studies, evaluating this technique in terms of safety and efficacy. In particular, our studies have shown that superficial tumors can be treated using a non-invasive mold technique on an outpatient basis without adverse reactions. The next generation of image-guided brachytherapy using HDR has been discussed. In conclusion, although concrete evidence is yet to be produced with a sophisticated study in a reproducible manner, HDR brachytherapy remains an important option for treatment of oral cancer.