Brachytherapy of stage II mobile tongue carcinoma. Prediction of local control and QOL

The combination of volumetric arc radiation therapy and boost high-dose rate interstitial brachytherapy for T3N2c tongue cancer: a technical report

Currently, tongue cancers are primarily managed by surgery, and interstitial brachytherapy is only recommended for a selected group of early state T1-2N0 patients who refuse surgery or are medically inoperable. In this report, a case with T3N2cM0 tongue cancer who has been effectively treated by the combination of concurrent chemoradiotherapy involving volumetric arc therapy and boost high-dose rate interstitial brachytherapy is presented. Of course, surgery remains the main treatment strategy for tongue cancer patients; however, the authors believe that if volumetric arc therapy is carefully planned to reduce the mandible dose as much as possible and high-dose rate interstitial brachytherapy with a mouthpiece that protects the mandible is combined, it is possible to treat T3N2 disease, and this can be considered for patients who want to preserve organ function.

Evaluation of radiodensity and dimensional stability of polymeric materials used for oral stents during external beam radiotherapy of head and neck carcinomas

Purpose

Intraoral stents protect the healthy tissues from ionizing radiation during external beam radiotherapy reducing mucositis, hyposalivation and osteoradionecrosis. This study investigated the radiodensity and dimensional stability of polymeric materials for suitability in construction of intraoral stents and aimed to provide clinical guidelines.

Methods

Specimens were fabricated using 4 material types namely, resin composite (ProTemp-PRO), polymethylmethacrylate (PMMA) (Enamel Temp Plus-ETP, Palapress-PAL, TAB 2000-TAB), polycaprolactone (Orfit-ORF) and silicone (Adisil-ADI, Lab Putty-LAB, Memosil2-MEM, Optosil-OPT, President Plus-PRE, Siolaplast A-SIA). They were randomly assigned to measure their radiodensity in Hounsfield Units (HU) (12x12x11mm³) (N_radiodensity = 66; n = 6) using a computer tomograph (CBCT, Toshiba Aquillon LB scanner) at baseline and after 6 weeks. The scanning protocol was applied with and without single energy metal artifact reduction (SEMAR) scans using a slice thickness of 1 and 5 mm. The same materials have been tested for their dimensional stability (µm³) at baseline, 1, 6, 12, 24 h, 3 and 6 weeks (14 × 4 × 2 mm³) (N_dimension = 55; n = 5 per material) using stereolithography (STL) files generated by a lab scanner (L2i, Imetric4D, Courgenay, Switzerland) and analyzed using a matching software (Geomagic ControlX 2020, 3D Systems). Data were analyzed using a paired t-test (alpha = 0.05).

Results

Radiodensity values (HU) were significantly affected by the material classification (p < 0.05). Polycaprolactone (43.6) presented significantly lower HU values followed by PMMA (91.3-414.9) than those of silicone materials (292.8-874.5). In terms of dimensional stability (µm³), PMMA materials (Δ:1.53-2.68) and resin composite (Δ:2.89) were significantly more dimensionally stable compared to those of silicone materials (Δ:13.64-6.63) and polycaprolactone (Δ:-0.76) and (p < 0.05).

Conclusion

For fabricating intraoral stents, when reduced radiodensity values are required polycaprolactone could be recommended as it fulfils the requirements for reduced radiodensity and dimensional stability. Among all silicone materials, OPT and MEM can be recommended based on the low HU and dimensional stability.

Population-based comparative survival analysis of surgery with or without adjuvant radiotherapy and non-operative primary radiotherapy in patients with early-stage oral tongue squamous cell carcinoma

Purpose

Although recent clinical guidelines do allow primary radiotherapy for selected patients with early-stage oral tongue cancer, there has been little knowledge on the treatment outcomes of non-operative radiotherapy using modern treatment techniques. This study evaluated recent prognostic differences between primary radiotherapy and surgical resection in T1‒2N0 oral tongue squamous cell carcinoma.

Methods

Patients diagnosed with T1‒2N0 oral tongue squamous cell carcinoma were identified from the Surveillance, Epidemiology, and End Results database. After propensity score matching, the disease-specific survival of primary radiotherapy and surgery was compared.

Results

From a total of 8,458 patients initially identified, we defined matched cohorts: cohort A, comparing surgery alone vs. primary radiotherapy (n = 230 vs. 230), and cohort B, comparing surgery plus adjuvant radiotherapy vs. primary radiotherapy (n = 230 vs. 230). The 7-year disease-specific survival rates were 77% vs. 35% (cohort A) and 65% vs. 35% (cohort B) (P < 0.001 for all comparisons). Primary radiotherapy was independently associated with worse disease-specific survival in both cohorts A (hazard ratio 4.06; 95% confidence interval 2.53‒6.52) and B (hazard ratio 2.81; 95% confidence interval 1.96‒4.04). Time-course hazard rate function plots showed a distinct short-term risk increment in disease-specific mortality in the primary radiotherapy group.

Conclusion

In the contemporary treatment era, the use of radiotherapy as a definitive treatment resulted in an inferior prognosis in patients with T1‒2N0 oral tongue squamous cell carcinoma. The present population-based data suggest that primary radiotherapy cannot be used as an alternative to surgical management and it needs to be avoided as much as possible in early-stage tumors.

Estimation of whole-body radiation exposure from brachytherapy for oral cancer using a Monte Carlo simulation

Early stage oral cancer can be cured with oral brachytherapy, but whole-body radiation exposure status has not been previously studied. Recently, the International Commission on Radiological Protection Committee (ICRP) recommended the use of ICRP phantoms to estimate radiation exposure from external and internal radiation sources. In this study, we used a Monte Carlo simulation with ICRP phantoms to estimate whole-body exposure from oral brachytherapy. We used a Particle and Heavy Ion Transport code System (PHITS) to model oral brachytherapy with 192Ir hairpins and 198Au grains and to perform a Monte Carlo simulation on the ICRP adult reference computational phantoms. To confirm the simulations, we also computed local dose distributions from these small sources, and compared them with the results from Oncentra manual Low Dose Rate Treatment Planning (mLDR) software which is used in day-to-day clinical practice. We successfully obtained data on absorbed dose for each organ in males and females. Sex-averaged equivalent doses were 0.547 and 0.710 Sv with 192Ir hairpins and 198Au grains, respectively. Simulation with PHITS was reliable when compared with an alternative computational technique using mLDR software. We concluded that the absorbed dose for each organ and whole-body exposure from oral brachytherapy can be estimated with Monte Carlo simulation using PHITS on ICRP reference phantoms. Effective doses for patients with oral cancer were obtained.

Preventing Complications from High-Dose Rate Brachytherapy when Treating Mobile Tongue Cancer via the Application of a Modular Lead-Lined Spacer

PURPOSE

To point out the advantages and drawbacks of high-dose rate brachytherapy in the treatment of mobile tongue cancer and indicate the clinical importance of modular lead-lined spacers when applying this technique to patients.

METHODS

First, all basic steps to construct the modular spacer are shown. Second, we simulate and evaluate the dose rate reduction for a wide range of spacer configurations.

RESULTS

With increasing distance to the source absorbed doses dropped considerably. Significantly more shielding was obtained when lead was added to the spacer and this effect was most pronounced on shorter (i.e. more clinically relevant) distances to the source.

CONCLUSIONS

The modular spacer represents an important addition to the planning and treatment stages of mobile tongue cancer using HDR-ISBT.

High-dose-rate interstitial brachytherapy in early stage oral tongue cancer - 15 year experience from a tertiary care institute

Purpose

To determine outcomes of interstitial high-dose-rate brachytherapy (HDR-BT) in patients with early stage oral tongue cancer.

Material and methods

Ninety-two patients with stage I and II oral tongue cancer were treated with HDR-BT between 1999 and 2014: brachytherapy alone = 62 (67.4%), and combination of external beam radiotherapy (EBRT) and brachytherapy = 30 (32.6%). Median follow-up was 53.5 months. Patterns of failure, overall survival (OS), disease-free survival (DFS), local control rates (LCR), and nodal control rates (NCR) were determined.

Results

5-year OS, DFS, LCR, and NCR were 73.2%, 58.2%, 64.2%, and 83.8%, respectively. In total, 43 patients (46.7%) failed treatment: isolated local failures = 28 (30.4%), isolated nodal failures = 8 (8.7%), both local and regional failures = 7 (7.6%). While in T1 stage, 5 year LCR were significantly higher in brachytherapy alone group compared to combined EBRT and brachytherapy group (81.7% vs. 62.5%, p = 0.04), the isolated nodal failure rates were not significantly different among the two groups. For T2 stage, NCR were higher in combined EBRT and brachytherapy group compared to brachytherapy alone (92.9% vs. 74.3%). Acute mucositis (grade ≥ 2) was seen more in brachytherapy alone group compared to the combined modality group (87% vs. 66%), and this correlated significantly with the higher biological equivalent dose (BED) in the brachytherapy alone group.

Conclusions

Our study recommends treating patients with brachytherapy alone in T1 stage, and demonstrates the need for addressing nodal region either by neck dissection or nodal irradiation in T2 stage patients. Also, the study highlights the need for dose escalation (from the doses used in the study) in both T1 and T2 stage tumors when using interstitial brachytherapy either as sole modality or as a boost.

198Au grain implantation for early tongue cancer in patients of advanced age or poor performance status

Brachytherapy using (198)Au grains is minimally invasive and the only curative treatment for early tongue cancer in patients of advanced age or poor performance status available in our institution. From March 1993 to February 2008, (198)Au grains were used to treat a group of 96 Stage I-II tongue cancer patients who could not undergo surgery or brachytherapy using (192)Ir pins because of an advanced age (≥75 years) or poor performance status (≥2). The patients were followed for 3.9 ± 3.3 years, and the cause-specific survival and local control rates were determined. Survival analyses were performed using the Kaplan-Meier method, and univariate and multivariate analyses were performed using the Cox proportional hazard model. The results were compared with those for a group of 193 early tongue-cancer patients who underwent treatment using iridium pins. The 5-year cause-specific survival and local control rates of the (198)Au grains group were 71% and 68%, respectively, both of which were 16% lower than the corresponding rates for the (192)Ir pins group. Our study demonstrated that as the last curative treatment available, (198)Au grain implantation could be used to achieve moderate treatment results for early tongue cancer in patients of advanced age or poor performance status.

New Management Strategies of Oral Tongue Cancer in Bangladesh

INTRODUCTION

Malignancies of the tongue represent one of the greatest management challenges for the maxillofacial surgeons as well as oncologists, because of the adverse effects of treatment on oral and pharyngeal function, the eventual quality of life, and the poor prognosis of advanced disease. Therefore, it is important to use judgment and experience in determining the best method of treatment.

MATERIAL AND METHODS

We reviewed forty cases of oral tongue cancer patients admitted in the Dental and Facio-Maxillary Surgical Oncology department in National Institute of Cancer Research and Hospital, and department of Oral and Maxillofacial Surgery, Dhaka Dental College and Hospital, Dhaka, Bangladesh, during the past four years and followed till the lesion healed or recurred and followed later on upto two years. All cases were thoroughly examined, investigated with routine blood examinations and radiography of the involved region. Preoperative biopsy of the lesion and staging was done in each and every case. Postoperative biopsy was taken where there was a doubt about the possibility of recurrence.

RESULTS

Squamous cell carcinoma (well differentiated) is by far the most common malignancy of the oral tongue. Generally a correlation is recognized between tumor size, nodal presence, metastasis, and eventual prognosis. When surgeons detect oral tongue cancer at an early stage, they can often treat it with surgery or can, often treat it with surgery or radiation. In later stages the cancer may require a combination of surgery, radiation and chemotherapy.

CONCLUSION

Standard and uniform protocol has not been explored till now for the practice in our country. So current management strategies of oral tongue cancer cannot be underestimated.

Brachytherapy for tongue cancer in the very elderly is an alternative to external beam radiation

BACKGROUND

The result of curative treatment for very elderly patients with tongue carcinoma has not been reported to date. We retrospectively reviewed the results of brachytherapy in 125 the patients aged over 75 years.

METHODS

The results of brachytherapy in 125 patients, 75 years old or older, with Stage I or II squamous cell carcinoma of the oral tongue were reviewed. The 125 cases consisted of 31 Stage I and 94 Stage II cases; 67 patients were under 80 years old and 58 were over 80 years old. All patients were treated using low-dose-rate brachytherapy ((198)Au/(222)Rn: 59 cases; (192)Ir: 38 cases; (226)Ra/(137)Cs: 28 cases).

RESULTS

None of the patients stopped treatment during the course of brachytherapy. The 3 year and 5 year control rates of the primary lesions were both 86%. Post-brachytherapy neck node metastasis was diagnosed in 43 cases and radical neck dissection was performed for 24 cases (21 of the 24 cases were under 80 years old). As a result, the 7 year disease-specific survival (DSS) rate for patients aged under 80 years old was 70% and 41% for those over 80 years old (p = 0.03).

CONCLUSION

The brachytherapy for elderly patients with tongue cancer was safe, and the control of the primary lesion was almost the same as in younger patients. However, modalities available to treat neck node metastasis are limited. More conservative surgical approaches combined with post-operative irradiation may be advocated for neck node metastasis for elderly patients with tongue cancer.

Current status and perspectives of brachytherapy for head and neck cancer

Brachytherapy delivers a high radiation dose to a limited volume while sparing surrounding normal tissues. In head and neck cancer, severe soft-tissue damage and bone damage to the mandible has decreased markedly since the introduction of computer dosimetry and the use of spacers during treatment. For the curative treatment of head and neck cancer, the selection of brachytherapy sources from among the several linear and small permanent implant sources available, not only according to the tumor site but also according to the patient's physical and mental condition is important. Following the successful treatment of early head and neck cancer by brachytherapy, two major problems and one minor problem may confront the physician. The major problems are neck node metastasis and a second primary cancer of the respiratory tract or upper digestive tract, and the minor problem is radiation-induced cancer.