High dose rate brachytherapy for oral cancer

Can interventional radiotherapy (brachytherapy) be an alternative to surgery in early-stage oral cavity cancer? A systematic review

PURPOSE

Brachytherapy (BT), also known as interventional radiotherapy (IRT), has proven its utility in the treatment of localized tumors. The aim of this review was to examine the efficacy of modern BT in early-stage oral cavity cancer (OCC) in terms of local control (LC), overall survival (OS), disease-free survival (DFS), cancer-specific survival (CSS), and safety.

METHODS

The SPIDER framework was used, with sample (S), phenomena of interest (PI), design (D), evaluation (E), and research type (R) corresponding to early-stage oral cavity cancer (S); BT (PI); named types of qualitative data collection and analysis (D); LC, OS, DFS, CSS, and toxicity (E); qualitative method (R). Systematic research using PubMed and Scopus was performed to identify full articles evaluating the efficacy of BT in patients with early-stage OCC. The studies were identified using medical subject headings (MeSH). We also performed a PubMed search with the keywords "brachytherapy oral cavity cancer, surgery." The search was restricted to the English language. The timeframe 2002-2022 as year of publication was considered. We analyzed clinical studies of patients with OCC treated with BT alone only as full text; conference papers, surveys, letters, editorials, book chapters, and reviews were excluded.

RESULTS

The literature search resulted in 517 articles. After the selection process, 7 studies fulfilled the inclusion criteria and were included in this review, totaling 456 patients with early-stage node-negative OCC who were treated with BT alone (304 patients). Five-year LC, DFS, and OS for the BT group were 60-100%, 82-91%, and 50-84%, respectively.

CONCLUSION

In conclusion, our review suggests that BT is effective in the treatment of early-stage OCC, particularly for T1N0 of the lip, mobile tongue, and buccal mucosa cancers, with good functional and toxicity profiles.

Dosimetric comparison of postoperative interstitial high-dose-rate brachytherapy and modern external beam radiotherapy modalities in tongue and floor of the mouth tumours in terms of doses to critical organs

BACKGROUND

The aim of the study was to dosimetrically compare interstitial high-dose-rate (HDR) brachytherapy (BT) and modern external beam radiotherapy modalities, as volumetric modulated arc therapy (VMAT) and stereotactic radiotherapy with Cyberknife (CK) of tumours of the tongue and floor of the mouth in terms of dose to the critical organs.

PATIENTS AND METHODS

In National Institute of Oncology, Budapest, between March 2013 and August 2022 twenty patients (11 male/9 female) with stage T1-3N0M0 tongue (n = 14) and floor of mouth (n = 6) tumours received postoperative radiotherapy because of close/positive surgical margin and/or lymphovascular and/or perineural invasion. High-dose-rate interstitial brachytherapy applying flexible plastic catheters with a total dose of 15 × 3 Gy was used for treatment. In addition to BT plans VMAT and stereotactic CK plans were also made in all cases, using the same fractionation scheme and dose prescription. As for the organs at risk, the doses to the mandible, the ipsilateral and the contralateral salivary glands were compared.

RESULTS

The mean volume of the planning target volume (PTV) was 12.5 cm3, 26.5 cm3 and 17.5 cm3 in BT, VMAT and CK techniques, respectively, due to different safety margin protocols. The dose to the mandible was the most favourable with BT, as for the salivary glands (parotid and submandibular) the CK technique resulted in the lowest dose. The highest dose to the critical organs was observed with the VMAT technique. The mean values of D2cm3 and D0.1cm3 for the critical organs were as follows for BT, VMAT and CK plans: 47.4% and 73.9%, 92.2% and 101.8%, 68.4% and 92.3% for the mandible, 4.8% and 6.7%, 7.3% and 13.8%, 2.3% and 5.1% for the ipsilateral parotid gland, 3.5% and 4.9%, 6.8% and 10.9%, 1.5% and 3.3% for the contralateral parotid gland, 7.3% and 9.4%, 9.0% and 14.3%, 3.6% and 5.6% for the contralateral submandibular gland.

CONCLUSIONS

The present results confirm that BT, despite being an invasive technique, is dosimetrically clearly beneficial in the treatment of oral cavity tumours and is a modality worth considering when applying radiotherapy, not only as definitive treatment, but also postoperatively. The use of the CK in the head and neck region requires further investigation.

Geographic and demographic distribution and access to brachytherapy in India with its implications on cancer care

PURPOSE

Geographic access to medical care varies for nearly every specialty in India. Given the special nature of its treatments, which sometimes necessitate numerous visits over a lengthy period, and the substantial-high fixed cost infrastructure requirements for radiation facilities, radiation oncology is particularly prone to regional inequities in access to care. Brachytherapy (BT) is emblematic of several of these access difficulties since it necessitates specialized equipment, the capacity to maintain a radioactive source, and particular skill sets. The study was conducted to report the availability of BT treatment units in relation to state-level population, overall cancer incidence, and gynecologic cancer incidence.

METHODS AND MATERIALS

The availability of BT resources at the state level in India was and the population of each state was estimated using data from the Government of India's Census. The number of cancer cases was approximated for each state and union territory. The total number of gynecological cancers that required BT was determined. The BT infrastructure was also compared to those of other nations in terms of the number of BT units available per million people and for various malignancies.

RESULTS

A heterogeneous geographic distribution of BT units was noted across India. India has one BT unit for every 42,93,031 population. The maximum deficit was seen in Uttar Pradesh, Bihar, Rajasthan, and Odisha. Among the states having BT units, the maximum units per 10,000 cancer patients was noted in Delhi (7), Maharashtra (5) and Tamil Nadu (4) and the least was noted in the Northeastern states (<1), Jharkhand, Odisha, and Uttar Pradesh. In BT of gynecological malignancies alone an infrastructural deficit ranging from 1 to 75 units were noted across the states. It was noted that only 104 out of the 613 medical colleges in India had BT facilities. On comparing the BT infrastructure status with other countries India had one BT machine for every 4,181 cancer patients when compared to United States (1 every 2,956 patients), Germany (2,754 patients), Japan (4,303 patients), Africa (10,564) and Brazil (4,555 patients).

CONCLUSION

The study identified the deficits of BT facilities in terms of geographic and demographic aspects. This research provides a roadmap for the development of BT infrastructure in India.

Is There Still a Place for Brachytherapy in the Modern Treatment of Early-Stage Oral Cancer?

Simple Summary

Brachytherapy involves the direct application of radioactive sources to the tumour. This technique is characterised by a delivery of high dose of radiation to the target volume and simultaneous sparring of healthy tissues. Historically, low-dose-rate brachytherapy played an important role in the treatment of early-stage oral cancer, with treatment outcomes that were comparable to surgery. Interest in brachytherapy as a primary treatment for oral cancer has declined in recent years due to the emergence of better surgical techniques, to advances in external beam radiotherapy, and to concerns regarding toxicity of modern high-dose-rate brachytherapy. At present, the main indications for brachytherapy are in the postoperative setting due to the superior dose conformity and better quality of life offered by brachytherapy compared to external beam radiation therapy. Postoperative brachytherapy can be administered as a monotherapy in early-stage tumours (T1N0) and in combination with elective neck dissection or EBRT to treat larger or deeper tumours. Brachytherapy yields excellent results for lip carcinoma in older patients and in tumours with unfavourable localisations. Brachytherapy is an effective salvage therapy for local recurrences in previously-irradiated areas.

Abstract

Brachytherapy (BT) involves the direct application of radioactive sources to the tumour. This technique is characterised by a steep dose gradient, the delivery of high-dose radiation to the target volume centre, and the sparing of surrounding healthy tissues. Low-dose-rate (LDR) BT and manual afterloading played an important role in the treatment of early-stage oral cancer, with treatment outcomes that were comparable to surgery. Interest in BT as a primary treatment for oral cancer has declined in recent years due to the emergence of better surgical techniques, the switch from LDR BT to high-dose-rate (HDR) BT (which has a higher risk of complications), and to advances in external beam radiotherapy (EBRT). At present, the main indications for BT are in the postoperative setting due to the superior dose conformity and better quality of life offered by BT versus EBRT. Postoperative BT can be administered as monotherapy in early-stage (T1N0) cancers and in combination with elective neck dissection or EBRT to treat larger or deeper tumours. BT yields excellent results for lip carcinoma in older patients and in tumours with unfavourable localisations. BT is an effective salvage therapy for local recurrences in previously-irradiated areas. Despite its many advantages, brachytherapy is a complex treatment requiring meticulous technique and close cooperation between the radiation oncologist, physicist, and surgeon.

Brachytherapy Approach Using 177Lu Conjugated Gold Nanostars and Evaluation of Biodistribution, Tumor Retention, Dosimetry and Therapeutic Efficacy in Head and Neck Tumor Model

Brachytherapy can provide sufficient doses to head and neck squamous cell carcinoma (HNSCC) with minimal damage to nearby normal tissues. In this study, the β^--emitter ¹⁷⁷Lu was conjugated to DTPA-polyethylene glycol (PEG) decorated gold nanostars (¹⁷⁷Lu-DTPA-pAuNS) used in surface-enhanced Raman scattering and photothermal therapy (PTT). The accumulation and therapeutic efficacy of ¹⁷⁷Lu-DTPA-pAuNS were compared with those of ¹⁷⁷Lu-DTPA on an orthotopic HNSCC tumor model. The SPECT/CT imaging and biodistribution studies showed that ¹⁷⁷Lu-DTPA-pAuNS can be accumulated in the tumor up to 15 days, but ¹⁷⁷Lu-DTPA could not be detected at 24 h after injection. The tumor viability and growth were suppressed by injected ¹⁷⁷Lu-DTPA-pAuNS but not nonconjugated ¹⁷⁷Lu-DTPA, as evaluated by bioluminescent imaging. The radiation-absorbed dose of the normal organ was the highest in the liver (0.33 mSv/MBq) estimated in a 73 kg adult, but that of tumorsphere (0.5 g) was 3.55 mGy/MBq, while intravenous injection of ¹⁷⁷Lu-DTPA-pAuNS resulted in 1.97 mSv/MBq and 0.13 mGy/MBq for liver and tumorsphere, respectively. We also observed further enhancement of tumor-suppressive effects by a combination of ¹⁷⁷Lu-DTPA-pAuNS and PTT compared to ¹⁷⁷Lu-DTPA-pAuNS alone. In conclusion, ¹⁷⁷Lu-DTPA-pAuNS may be considered as a potential radiopharmaceutical agent for HNSCC brachytherapy.

ACR-ABS-ASTRO practice parameter for the performance of radionuclide-based high-dose-rate brachytherapy

PURPOSE

This practice parameter aims to detail the processes, qualifications of personnel, patient selection, equipment, patient and personnel safety, documentation, and quality control and improvement necessary for an HDR brachytherapy program.

METHODS AND MATERIALS

This practice parameter was revised collaboratively by the American College of Radiology (ACR), the American Brachytherapy Society (ABS), and the American Society for Radiation Oncology (ASTRO).

RESULTS

Brachytherapy is a radiotherapeutic modality in which radionuclide or electronic sources are used to deliver a radiation dose at a distance of up to a few centimeters by surface, intracavitary, intraluminal, or interstitial application. Brachytherapy alone or combined with external beam radiotherapy plays an important role in the management and treatment of patients with cancer. High-dose-rate (HDR) brachytherapy uses radionuclides, such as iridium-192, at dose rates of ≥12 Gy/hr to a designated target point or volume, and it is an important treatment for a variety of malignant and benign conditions. Its use allows for application of high doses of radiation to defined target volumes with relative sparing of adjacent critical structures.

CONCLUSIONS

HDR brachytherapy requires detailed attention to personnel, equipment, patient and personnel safety, and continuing staff education. Coordination between the radiation oncologist and treatment planning staff and effective quality assurance procedures are important components of successful HDR brachytherapy programs.

Brachytherapy in head and neck malignancies: Indian Brachytherapy Society (IBS) recommendations and guidelines

PURPOSE

Brachytherapy (BT) forms major treatment modality in squamous cell carcinoma of head and neck cancers (HNC). However, there is a dearth of literature and guidelines for the use in various indications. High-dose-rate brachytherapy (HDR-BT) in Indian scenario is an important treatment modality, and the recommendations in this guidelines aim to provide the necessary recommendations for the use of HDR-BT for uniform application across the country in patients with HNC.

MATERIAL AND METHODS

A panel consisting of members of the Indian Brachytherapy Society (IBS), based on their clinical experience was invited. The process involved defining important steps, precautions, target volumes and indications, thorough literature review, and discussion with fellow members. The guidelines were established and formulated the recommendations for HDR-BT based on available evidences and individual experience for sites, relevant to Indian settings.

RESULTS

The IBS recommends the use of HDR brachytherapy as a part of treatment of head and neck tumors. The scope of these guidelines and recommendations included practical suggestions, ensuring efficient use of brachytherapy treatment as radical with external beam radiotherapy (EBRT) boost, palliative and adjuvant as definitive, or re-radiation as salvage for HNC in India. The IBS has made specific site-wise recommendations for previously untreated and recurrent HNC patients on their selection criteria, implant techniques, target volume definition, and HDR treatment parameters, such as time, dose rate, total dose, and fractionation schedules. Limited experience exists with HDR-BT in patients with head and neck cancers in India and across the globe.

CONCLUSIONS

IBS provided a consensus statement and guidelines for the head and neck brachytherapy and believed that these recommendations will overcome the fear of practicing radiation oncologists. This should generate interest amongst students and will help radiation oncologists all across the country to use the art of brachytherapy carefully in HNC patients, with better curative and salvage options.

A national surveillance study of the current status of reirradiation using brachytherapy in Japan

PURPOSE

This study aimed to explore the current status and pattern of practice for reirradiation using brachytherapy (ReRT-BT) through a survey in Japan.

MATERIALS AND METHODS

We distributed an e-mail-based questionnaire to 153 institutions equipped with high-dose-rate brachytherapy facilities.

RESULTS

We received responses from 76 institutions (49.7%). Forty-three of these institutions performed ReRT-BT and 42 institutions (55%) performed ReRT-BT during 2009-2018. However, 29 of the 42 institutions (69%) reported difficulty in obtaining ReRT-BT case information from their respective databases. Almost all the institutions encountered insufficient database system to extract details about the ReRT-BT cases. Responses from 33 institutions included the number of ReRT-BT cases; this increased from 90 in the period 2009-2013 (institution median = 0.5; 0-16) to 172 in the period 2014-2018 (institution median = 2; 0-26). Nine institutions had to perform ReRT-BT for more than one case per year. The major location for cancer treatment was the pelvis (94%), followed by the head and neck (5%) and others (1%). In six site-specific scenarios, barring uterine corpus cancer recurrence, more than 90% of radiation oncologists agreed to perform ReRT-BT, whereas other areas (head and neck, prostate, and rectal cancer) gained 16-37% agreement.

CONCLUSIONS

This decade saw an increase in the number of ReRT-BT cases in Japan and radiation oncologists' interest in ReRT-BT as a viable therapeutic option. However, scarce availability, immature education system, and insufficient database system are barriers to further consensus building.

Image-guided interstitial brachytherapy boost for keratinizing squamous cell carcinoma of inferior wall of the nasopharynx

High-dose-rate interstitial brachytherapy (HDR-ISBT) is relatively rarely applied for the head and neck cancer because of its anatomical complexity and difficulty of applicator placement. However, its dose distribution is more confined even better than intensity-modulated radiation therapy (IMRT) and can deliver a higher dose while sparing surrounding normal tissues. In this case report, the effectiveness of HDR-ISBT as a boost following IMRT for keratinizing squamous cell carcinoma of nasopharynx was presented. A 76-year-old female who suffered from cT3N0M0 keratinizing squamous cell carcinoma of the nasopharynx was treated with definitive concurrent chemoradiation therapy involving IMRT. However, physical examination and laryngoscope fibre finding showed evident residual tumour at 60 Gy of IMRT, then, boost HDR-ISBT was proposed. After delivering 66 Gy of IMRT, CT image-guided HDR-ISBT 4 Gy in a single fraction was performed under local anaesthesia and sedation. MRI taken 5 months after HDR-ISBT showed remarkable shrinkage of the primary tumour. After HDR-ISBT, the remaining session of IMRT was delivered from the next day until 70 Gy in 35 fractions. It was demonstrated that boost HDR-ISBT combined with IMRT for keratinizing squamous cell carcinoma of the nasopharynx was performed safely and showed favourable efficacy.

Image-guided interstitial brachytherapy boost for nasopharyngeal carcinoma: technical aspects

Nasopharyngeal cancer generally responds well to concurrent chemoradiotherapy (CCRT). However, there is a small group of patients who respond poorly to CCRT, and experience local residual tumor or local relapse. Although several attempts have been performed to such a group of patients including re-irradiation with external beam radiation therapy (EBRT) or salvage surgery, clinical results remain unsatisfactory. Intracavitary brachytherapy (ICBT) boost after CCRT with EBRT has been explored, however, its efficacy is limited to those with superficial residual tumors. For those residual tumors thickness with more than 5 mm, interstitial brachytherapy (ISBT) boost would be an appropriate modality of choice. Here, we describe technical aspects of the high-dose-rate interstitial brachytherapy (HDR-ISBT) boost for nasopharyngeal cancer (NPC) patients who responded poorly to the CCRT with EBRT.

The Effect of High Dose Rate Interstitial Implant on Early and Locally Advanced Oral Cavity Cancers: Update and Long-Term Follow-Up Study

Introduction Brachytherapy, with or without external beam radiation therapy (EBRT), can be an alternative to surgery for organ preservation in early and locally advanced oral cavity cancers. This study aims to evaluate the effect of high dose rate (HDR) interstitial brachytherapy on early and locally advanced squamous cell carcinoma (SCC) of the oral cavity when used alone or as a boost to EBRT. Methods A total of 125 patients with histologically proven stage T1-3/N0-1 SCC of the oral cavity were included in the study. A total of 15 patients with stage I disease received an interstitial implant dose of 3,850 cGy at 350 cGy per fraction, two fractions a day. Another 53 patients had stage II, and 57 patients had stage III disease; these patients received EBRT of 50 Gy in 25 fractions along with an HDR brachytherapy boost of 21 Gy in seven fractions of 3 Gy per fraction twice daily. The stage III patients also received concurrent chemotherapy with injections of cisplatin (70 mg/m2) given every three weeks for three days in divided doses. All node-positive patients received a boost to the node of up to 64 Gy by external beam radiation. Disease response rates, five-year disease-free survival rates, and toxicities were analyzed. Results The median follow-up was 60 months. Among the patients, 103 (82.4%) had a complete response, while 22 (17.6%) had residual disease and were referred for surgical salvage. The five-year disease-free survival was 100% in stage I, 83% in stage II, and 77.2% in stage III; 4% of patients developed grade 3 acute skin toxicity and 23.2% developed acute grade 3 mucositis. Eleven patients died during the follow-up period. Two patients died due to myocardial infarction but had achieved a complete tumor response. One patient had pulmonary tuberculosis and died due to fulminant infection after three years of disease-free survival period. One patient developed a second primary in the brain stem that presented with quadriplegia and expired. Seven patients died due to the progression of the initial disease. Conclusions Proper brachytherapy technique and meticulous planning can minimize the toxicity while providing better tumor control and achieve high local control rates. Brachytherapy, with or without EBRT, can be a surrogate to surgery in early oral cavity cancers as it can achieve organ preservation while providing good functional outcomes.

Per-oral interstitial brachytherapy catheter insertion for boost in case of recurrent tonsillar carcinoma: dosimetry and clinical outcome

High-dose-rate interstitial brachytherapy (HDR-ISBT) is relatively rarely applied for the head and neck cancer. However, its dose distribution is more confined than intensity modulated radiation therapy (IMRT) and can deliver higher dose while sparing surrounding normal tissues. In this case report, the effectiveness of HDR-ISBT as a boost following IMRT for post-operative recurrent oropharyngeal cancer patient was indicated. A 73-year-old male who developed local recurrence after surgery for oropharyngeal squamous cell carcinoma. Salvage IMRT up to 70 Gy concurrent with weekly cetuximab was planned. However, CT taken at 60 Gy found a residual tumor, then, boost HDR-ISBT was proposed. 1 week after 60 Gy of IMRT, HDR-ISBT, 12 Gy in 2 fractions, was delivered under local anesthesia. MRI taken 2 months after HDR-ISBT showed no residual tumor. It was demonstrated that boost HDR-ISBT following IMRT for local recurrence of oropharyngeal cancer was performed safely and showed favorable efficacy.

Estimation of radiation shielding ability in electron therapy and brachytherapy with real time variable shape tungsten rubber

PURPOSE

To clarify the physical characteristics of a newly developed real time variable shape rubber containing tungsten (STR) with changes in heat and estimate its shielding abilities against electron beams and γ-rays from ¹⁹²Ir.

METHODS

Dynamic mechanical analysis for the STR (density = 7.3 g/cm³) was conducted at a frequency of 1.0 Hz in the temperature range of -60 °C to 60 °C. We evaluated tanδ, defined as the ratio (E″/E') between the storage modulus (E') and loss modulus (E″). The transmission rates were measured against 6- and 12-MeV electron beams and the percentage depth dose and lateral dose profile were compared with low-melting alloy (LMA). For the shielding rate of ¹⁹²Ir against γ-rays, measurement data and Monte Carlo simulation data were obtained with STR thickness ranging from 1.0 mm to 16.0 mm.

RESULTS

At 36 °C, the tanδ value was 0.520, while at 60 °C, this value was 1.016. For 6- and 12-MeV electron beams, the transmission rates decreased with increasing STR thickness and reached plateaus at approximately 1.0% and 4.0% with STR thickness of >7.0 and >12.0 mm, respectively. The dose distributions were almost equal to those for LMA. Against γ-rays, the thickness of STR that obtained a 50% attenuation rate for ¹⁹²Ir was 5.804 mm. The Monte Carlo calculation results were 2.6% higher on average than the measurement results.

CONCLUSION

The STR can be changed shape in real time at 60 °C and maintains its shape at body temperatures. It has adequate shielding abilities against megavoltage electron beams and γ-rays from ¹⁹²Ir.

Treatment of Stage I Hard Palate Cancer with High-Dose-Rate Brachytherapy Using Molds: Cost-Based Perspective

Introduction:

Treatment of T1N0M0 (T1 = greatest tumor size < 2 cm, N0 = regional lymph nodes not palpable by clinical examination, M0 = No evidence of distant metastasis) (Green FL, Page DL, Fleming ID, Fritz AG, Balch CM, Haller DG, Morrow M. AJCC Cancer Staging Manual. New York: Springer; 2002) lesions of hard palate carcinoma by radiotherapy carries equal results with the advantage of cosmesis and can avoid surgical complications. External beam radiotherapy (EBRT) will last for 6–8 weeks. Feasibility of high-dose-rate (HDR) intraoral mold brachytherapy is an alternative to EBRT, which is highly effective and reduces treatment time and is also cost-effective one, which can be practiced in a center without Linac facilities.

Materials and Methods:

Custom-made surface molds were prepared for each patient with dental wax, and HDR after loading tubes were placed as per tumor volume. After simulation, with the help of simulation check films, treatment was planned with PLATO Treatment Planning System (TPS) and optimization was carried out.

Results:

We treated six cases of T1N0M0 hard palate carcinoma by HDR intraoral mold brachytherapy. A total dose of 42–45 Gy in 14–15 fractions with 3 Gy per fraction, two fractions per day with a gap of minimum 6 h was administered between two fractions. (Gray [Gy] is the unit of absorbed dose of radiation by tissues. A total radiation dose of 42–45 Gy will be delivered as per radiobiological principles, in divided number of fractions, thereby the given dose of radiation will kill the major portion of the tumor cells, which were in various sensitive phases of cell cycle and at the same time, less damage to the normal tissues. The time between two fractions of radiation is 6 h, which is the experimentally proven optimal time for recovery of normal tissues from radiation damage and tumor tissues to enter into the sensitive phases of the cell cycle to radiation damage-late G2 and S phases). There was confluent mucositis and all the patients had a complete response and none of the patients had relapse.

Conclusion:

Early (T1N0M0) lesions of hard palate carcinoma with HDR intraoral mold brachytherapy will shorten overall duration of treatment time with excellent local control and toxicities as compared with EBRT.

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 interstitial brachytherapy in recurrent head and neck cancer: an effective salvage option

Purpose

High-dose-rate (HDR) interstitial brachytherapy has an established role in head and neck malignancies and offers good survival rates; however, there is scant data on improved local control (LC) and treatment-related complications in recurrent cases. We present our results in patients with recurrent head and neck cancers treated with HDR interstitial brachytherapy.

Material and methods

Twenty-five patients with recurrent head and neck cancers were treated with HDR interstitial brachytherapy using Iridium 192 between 2009 and 2016. Of these, 75% received radical brachytherapy, and 25% received external beam radiation therapy (EBRT) followed by brachytherapy boost. Treatment sites included oral cavity (15/25) and oropharynx (10/25). Median dose of 4.5 Gy was administered twice per day, with median total brachytherapy dose of 40.5 Gy in radical and 27 Gy for EBRT cases.

Results

With median follow-up of 25 months, 4 local recurrences were observed within first year of follow-up. Two-year local control and overall survival outcomes for the entire group were 75% and 68%, respectively. Local control rate with radical BRT vs. BRT as a boost following EBRT was found to be significant (2-year LCR 62% vs. 85%; p < 0.02). Dosimetric assessment revealed D₉₀ - 4.08 Gy, V₁₀₀ - 94.1%, V₁₅₀ - 24.7%, and V₂₀₀ - 10.1%. Xerostomia, altered taste, and dysphagia were the major complications commonly grade 1 and 2. Grade 3 toxicity was only 2%. Pre-treatment volume > 85 cc had a negative impact on overall survival (26 months vs. 12 months; p = 0.02), and interval time between primary and recurrence more than 15 months had an impact on the local control rate (p < 0.01).

Conclusions

Results of HDR interstitial brachytherapy have shown acceptable local control and overall survival rates along with tolerable toxicities and morbidity in recurrent head and neck cancers.

Comparison of the IPSA and HIPO algorithms for interstitial tongue high-dose-rate brachytherapy

Purpose

This study aimed to compare the inverse planning simulated annealing (IPSA) stochastic algorithm with the hybrid inverse planning and optimization (HIPO) algorithm for interstitial tongue high-dose-rate (HDR) brachytherapy.

Methods

Twenty patients who received radiotherapy for tongue cancer using interstitial HDR brachytherapy were retrospectively selected for this study. Oncentra Brachy v. 4.3 was used for IPSA and HIPO planning. Four to eight fixed catheter configurations were determined according to the target shape. During the optimization process, predetermined constrain values were used for each IPSA and HIPO plan. The dosimetric parameters and dwell time were analyzed to evaluate the performances of the plans.

Results

The total dwell time using IPSA was 4 seconds longer than that of HIPO. The number of active positions per catheter for the IPSA plans were approximately 2.5 fewer than those of the HIPO plans. The dose-volumetric parameters related to the clinical target volume with IPSA were lower than those with HIPO. In terms of the dose-volumetric parameters related to normal tissue, HIPO tended to associate with slightly higher values than IPSA, without statistical significance. After GrO, the target coverages were satisfied to clinical goal for all patients. The total dwell times was approximately increased by 10%.

Conclusions

The IPSA and HIPO dose optimization algorithms generate similar dosimetric results. In terms of the dwell time, HIPO appears to be more beneficial.

Dose-volume analysis of target volume and critical structures in computed tomography image-based multicatheter high-dose-rate interstitial brachytherapy for head and neck cancer

Purpose

To evaluate dose-volume relationships of target volume and critical structures in computed tomography (CT) image-based brachytherapy for head and neck cancer.

Material and methods

Thirty-seven patients with mobile tongue, floor of mouth, and base of tongue cancer treated with brachytherapy (post-operative alone and as a boost after external beam radiotherapy [EBRT], or definitive alone or as a boost after EBRT) were selected. Treatment plans were made using post-implant CT images. The fractionation schedule was 7-15 × 3-5 Gy for post-operative (with or without EBRT), 14-15 × 3 Gy for definitive alone, and 5-10 × 3 Gy for boost treatments. For the target volume, V₁₀₀, D₉₀, and dose non-uniformity ratio (DNR) were calculated. For the mandible, spinal cord and salivary glands doses to specified volumes were reported.

Results

The median values of V₁₀₀ and D₉₀ were 89.9% and 99.9%, respectively; the median values of DNR was 0.46. The median D_2cm³ of the mandible and spinal cord were 48.3% and 5.8%, respectively. The ipsilateral median D_2cm³ of parotid and submandibular glands were 6.4% and 12.5%, whereas on the contralateral side, the corresponding values were 5.3% and 7.0%, respectively.

Conclusions

Using conformal treatment planning, it was desirable to keep the dose to the mandible, spinal cord, and salivary glands at an acceptable level. The quantitative plan evaluation may help us find correlations between dosimetric parameters and clinical outcome, which may lead to improve the quality of the treatment, but it requires longer follow-up and results from other studies.

The American College of Radiology and the American Brachytherapy Society practice parameter for the performance of radionuclide-based high-dose-rate brachytherapy

Brachytherapy is a radiation therapy method in which radionuclide sources are used to deliver a radiation dose at a distance of up to a few centimeters by surface, intracavitary, intraluminal, or interstitial application. This practice parameter refers only to the use of radionuclides for brachytherapy. Brachytherapy alone or combined with external beam therapy plays an important role in the management and treatment of patients with cancer. High-dose-rate (HDR) brachytherapy uses radionuclides such as iridium-192 at dose rates of 20 cGy per minute (12 Gy per hour) or more to a designated target point or volume. High-dose-rate (HDR) brachytherapy is indicated for treating malignant or benign tumors where the treatment volume or targeted points are defined and accessible.

High-dose-rate interstitial brachytherapy in head and neck cancer: do we need a look back into a forgotten art - a single institute experience

Purpose

To evaluate the treatment outcomes with high-dose-rate (HDR) interstitial brachytherapy (HDR-BRT) in head and neck cancers (HNC).

Material and methods

Fifty-eight patients with HNC as per American Joint Committee on Cancer (AJCC) TNM staging criteria were analyzed retrospectively between 2008 and 2015. Forty-two patients received external beam radiotherapy (EBRT) with HDR-BRT and 16 patients received BRT alone. The survival was calculated with respect to median biological equivalent doses (BED) and median 2 Gy equivalent dose (EQD₂), keeping α/β = 10 for tumor. Loco-regional control and disease free survival was assessed.

Results

The median follow-up period was 25 months (2-84 months). The disease-free survival (DFS) probability at year 1 was 82.7%, and 68% at year 7. The overall survival probability was 91.3% at year 1 and 85.8% at year 7. The local control rate was 70%. The rate of recurrence was 30%. Distant metastasis rate was 17.2%. The median BED and EQD₂, respectively, were 86.78 Gy and 71.6 Gy. The DFS was 74.1% and 75.9% in patients receiving a dose more than median BED and EQD₂, respectively, and was 64.8% and 61.5% for less than the median dose.

Conclusions

The overall outcome was good with implementation of HDR-BRT used alone or as boost, and shows DFS as better when the dose received is more than the median BED and median EQD₂. The role of HDR-BRT in HNC is a proven, effective, and safe treatment method with excellent long term outcome as seen in this study, which reflects the need for reviving the forgotten art and science of interstitial brachytherapy in HNC.

Image-guided high-dose-rate brachytherapy of head and neck - a case series study

Purpose

The aim of the study was the evaluation of image guided transdermal application of interstitial brachytherapy in patients undergoing repeated irradiation for relapsed local tumor of the head and neck area.

Material and methods

The article describes transdermal application of interstitial high-dose-rate (HDR) brachytherapy in 4 patients treated due to relapsed local tumor in soft palate, submandibular area, laryngopharynx, as well as pterygoid muscles and maxillary sinus. The application was conducted under continuous computed tomography (CT)-image guidance (CT fluoroscopy). Patients qualified for this type of treatment had neoplastic lesions located deep under the skin surface. Because of their location, access to the lesions was limited, and the risk of damaging the adjacent tissues such as vessels and nerves was high. The following parameters have been evaluated: clinical response using RECIST 1.1, incidence of perisurgical complications using CTCAE 4.0 and the frequency of occurrence of radiotherapy related early morbidity using RTOG.

Results

Various radiation schemes were used, from 3 to 5 fractions of 3.5-5 Gy. The median total dose (D₉₀) was 20.6 Gy. Biologic effective dose (BED) and equivalent 2 Gy (DEQ₂) median doses were 30.4 Gy and 25.3 Gy, respectively. In the follow-up period of 3-7 months (the median value of 3.5 months), 2 patients had partial regression of the disease and in 2 others the neoplastic process was stabilized. None of the patients had serious complications of treatment (of 3^rd degree or higher).

Conclusions

Computed tomography-image guided brachytherapy proved to be a safe method of treatment in patients with local relapse in sites, in which traditional visually controlled application was impossible due to risk of complications. Despite short observation period and small study group, it seems justified to conduct prospective studies for the evaluation of efficacy and safety of CT-image guided brachytherapy.

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.

Evaluation of neuropathic pain occurring after high-dose-rate interstitial brachytherapy of oral tongue

PURPOSE

To recognize neuropathic pain as a complication of high-dose-rate (HDR) interstitial brachytherapy of oral tongue and to evaluate the possible causes of neuropathy.

MATERIAL AND METHODS

Twenty one patients who underwent interstitial brachytherapy for early cancer of oral tongue were evaluated. The patients either underwent primary brachytherapy (42-48 Gy at 3-4 Gy/fraction) or a boost (18-24 Gy at 3 Gy/fraction) after external radiation to 40 Gy. Lingual nerve was the nerve concerned and the sublingual space (SLS) was contoured as its surrogate. Dosimetric parameters were correlated with onset of pain.

RESULTS

Ten patients out of 21 (47.61%) developed painful neuropathy. Five patients of six (5/6) who underwent primary brachytherapy developed neuropathy. Five out of 15 (5/15) patients who underwent brachytherapy as a boost developed neuropathy. The patients who underwent primary brachytherapy were ten times more likely to develop neuropathy. Among the patients receiving boost treatment, the equivalent dose at 2 Gy/fraction (EQD2) to 2 cc of SLS was higher (39.25 Gy) in the patients who developed pain compared to those without pain (10.29 Gy).

CONCLUSIONS

This is the first report to recognize neuropathic pain as a complication of HDR brachytherapy of oral tongue. Patients undergoing primary brachytherapy were more likely to develop pain. Among other factors like dose to SLS, number of catheters, size of the primary tumor, and the dose rate, only dose to 2 cc of the SLS correlated with onset of pain. The SLS (containing the lingual nerve) may be considered an organ at risk to prevent the occurrence of this complication.

Endoscopy-guided brachytherapy for sinonasal and nasopharyngeal recurrences

OBJECTIVE/PURPOSE

To evaluate the preliminary results of perioperative endoscopy-guided brachytherapy (BT) in recurrent sinonasal and nasopharyngeal tumors already treated for their primary tumor with a full course of radiotherapy.

METHODS AND MATERIALS

Patients with recurrence and already treated with a previous full course of radiotherapy >65 Gy who underwent BT from December 2010 to January 2014 were taken into account for this work. Macroscopic disease was resected by an endoscopic approach, and catheters for BT were endoscopically positioned and fixed at the same time on the surgical bed. Surgery was performed under electromagnetic navigation guidance. The irradiation dose was 30 Gy in 12 fractions, 2.5 Gy each, twice a day, in 6 days.

RESULTS

We performed the endoscopy-guided BT 11 times in 9 patients; in two cases, no previous radiation therapy had been performed; and in one case, followup was too short to be considered. A total of 6 patients were eligible for the analysis. One patient underwent BT three times because of previous target margin recurrences. There were no immediate complications. The median and mean followups were 21 and 19 months, respectively. The median V90 and V85% were 93% and 95%, respectively. In one case, we had a transient deficit of the VI cranial nerve (G3), and in another case, we diagnosed a noncomplicated osteonecrosis (G2). The median disease-free survival is 12 months, and the median overall survival is 23 months.

CONCLUSIONS

The combination of endoscopy and BT seems to be a safe option for treating recurrent sinonasal and nasopharyngeal tumors.

Modern head and neck brachytherapy: from radium towards intensity modulated interventional brachytherapy

Intensity modulated brachytherapy (IMBT) is a modern development of classical interventional radiation therapy (brachytherapy), which allows the application of a high radiation dose sparing severe adverse events, thereby further improving the treatment outcome. Classical indications in head and neck (H&N) cancers are the face, the oral cavity, the naso- and oropharynx, the paranasal sinuses including base of skull, incomplete resections on important structures, and palliation. The application type can be curative, adjuvant or perioperative, as a boost to external beam radiation as well as without external beam radiation and with palliative intention. Due to the frequently used perioperative application method (intraoperative implantation of inactive applicators and postoperative performance of radiation), close interdisciplinary cooperation between surgical specialists (ENT-, dento-maxillary-facial-, neuro- and orbital surgeons), as well interventional radiotherapy (brachytherapy) experts are obligatory. Published results encourage the integration of IMBT into H&N therapy, thereby improving the prognosis and quality of life of patients.

Novel high dose rate lip brachytherapy technique to improve dose homogeneity and reduce toxicity by customized mold

PURPOSE/OBJECTIVES

The purpose of this study is to describe a novel brachytherapy technique for lip Squamous Cell Carcinoma, utilizing a customized mold with embedded brachytherapy sleeves, which separates the lip from the mandible, and improves dose homogeneity.

MATERIALS AND METHODS

Seven patients with T2 lip cancer treated with a "sandwich" technique of High Dose Rate (HDR) brachytherapy to the lip, consisting of interstitial catheters and a customized mold with embedded catheters, were reviewed for dosimetry and outcome using 3D planning. Dosimetric comparison was made between the "sandwich" technique to "classic" - interstitial catheters only plan. We compared dose volume histograms for Clinical Tumor Volume (CTV), normal tissue "hot spots" and mandible dose. We are reporting according to the ICRU 58 and calculated the Conformal Index (COIN) to show the advantage of our technique.

RESULTS

The seven patients (ages 36-81 years, male) had median follow-up of 47 months. Four patients received Brachytherapy and External Beam Radiation Therapy, 3 patients received brachytherapy alone. All achieved local control, with excellent esthetic and functional results. All patients are disease free. The Customized Mold Sandwich technique (CMS) reduced the high dose region receiving 150% (V150) by an average of 20% (range 1-47%), The low dose region (les then 90% of the prescribed dose) improved by 73% in average by using the CMS technique. The COIN value for the CMS was in average 0.92 as opposed to 0.88 for the interstitial catheter only. All differences (excluding the low dose region) were statistically significant.

CONCLUSION

The CMS technique significantly reduces the high dose volume and increases treatment homogeneity. This may reduce the potential toxicity to the lip and adjacent mandible, and results in excellent tumor control, cosmetic and functionality.

Evaluation of accuracy of B-spline transformation-based deformable image registration with different parameter settings for thoracic images

Deformable image registration (DIR) is fundamental technique for adaptive radiotherapy and image-guided radiotherapy. However, further improvement of DIR is still needed. We evaluated the accuracy of B-spline transformation-based DIR implemented in elastix. This registration package is largely based on the Insight Segmentation and Registration Toolkit (ITK), and several new functions were implemented to achieve high DIR accuracy. The purpose of this study was to clarify whether new functions implemented in elastix are useful for improving DIR accuracy. Thoracic 4D computed tomography images of ten patients with esophageal or lung cancer were studied. Datasets for these patients were provided by DIR-lab (dir-lab.com) and included a coordinate list of anatomical landmarks that had been manually identified. DIR between peak-inhale and peak-exhale images was performed with four types of parameter settings. The first one represents original ITK (Parameter 1). The second employs the new function of elastix (Parameter 2), and the third was created to verify whether new functions improve DIR accuracy while keeping computational time (Parameter 3). The last one partially employs a new function (Parameter 4). Registration errors for these parameter settings were calculated using the manually determined landmark pairs. 3D registration errors with standard deviation over all cases were 1.78 (1.57), 1.28 (1.10), 1.44 (1.09) and 1.36 (1.35) mm for Parameter 1, 2, 3 and 4, respectively, indicating that the new functions are useful for improving DIR accuracy, even while maintaining the computational time, and this B-spline-based DIR could be used clinically to achieve high-accuracy adaptive radiotherapy.

Reirradiation for patients with recurrence head and neck squamous cell carcinoma: a single-institution comparative study

BACKGROUND AND OBJECTIVE

In the last decade, the number of publications that report on the use of external beam radiotherapy and high-dose-rate brachytherapy (HDR-BRT) in the treatment of recurrent head and neck cancer has increased, but no studies compare external beam radiotherapy and HDR-BRT. The aim of this study was to evaluate and to compare the efficacy and toxicity of the three-dimensional conformal radiotherapy (3D-CRT) and HDR-BRT in the treatment of recurrent head and neck cancer.

MATERIAL AND METHODS

A total of 64 patients with head and neck cancer recurrence were randomly assigned at a 1:1 ratio to receive either 3D-CRT (50Gy/25 fractions) in the control group or HDR-BRT (30Gy/12 fraction) in the experimental group.

RESULTS

The overall survival rate of patients treated with HDR-BRT at 1 and 2-years was 74% and 67%, respectively, compare to 3D-CRT group - 51% and 32%, respectively (P=0.002). Local control at 1- and 2-years in patients who received HDR-BRT was 77% and 63% compare with 47% and 25%, respectively, for the patients who received the 3D-CRT (P<0.001). Most patients developed mild to moderate acute mucositis and dermatitis. In the 3D-CRT group, severe late toxicity was determined in 11 patients (35.5%), and in the HDR-BRT group, in 1 patient (3.1%) (P=0.001). There was no grade 5 toxicity.

CONCLUSIONS

Following our results, we concluded that HDR-BRT is a more effective and safer treatment approach for head and neck cancer recurrences than 3D-CRT.

High dose rate versus low dose rate brachytherapy for oral cancer--a meta-analysis of clinical trials

OBJECTIVE

To compare the efficacy and safety of high dose rate (HDR) and low dose rate (LDR) brachytherapy in treating early-stage oral cancer.

DATA SOURCES

A systematic search of MEDLINE, EMBASE and Cochrane Library databases, restricted to English language up to June 1, 2012, was performed to identify potentially relevant studies.

STUDY SELECTION

Only randomized controlled trials (RCT) and controlled trials that compared HDR to LDR brachytherapy in treatment of early-stage oral cancer (stages I, II and III) were of interest.

DATA EXTRACTION AND SYNTHESIS

Two investigators independently extracted data from retrieved studies and controversies were solved by discussion. Meta-analysis was performed using RevMan 5.1. One RCT and five controlled trials (607 patients: 447 for LDR and 160 for HDR) met the inclusion criteria. The odds ratio showed no statistically significant difference between LDR group and HDR group in terms of local recurrence (OR = 1.12, CI 95% 0.62-2.01), overall mortality (OR = 1.01, CI 95% 0.61-1.66) and Grade 3/4 complications (OR = 0.86, CI 95% 0.52-1.42).

CONCLUSIONS

This meta-analysis indicated that HDR brachytherapy was a comparable alternative to LDR brachytherapy in treatment of oral cancer. HDR brachytherapy might become a routine choice for early-stage oral cancer in the future.