Acquisition of equal or better planning results with interstitial brachytherapy when compared with intensity-modulated radiotherapy in tongue cancers

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.

Long term outcomes of Carcinoma Buccal Mucosa treated with High Dose Rate Interstitial Brachytherapy

PURPOSE

To analyze the long-term local control, overall survival and toxicity in Carcinoma Buccal Mucosa patients treated with interstitial brachytherapy.

METHODS AND MATERIALS

This analysis included patients diagnosed as Carcinoma Buccal Mucosa on biopsy and treated with radical brachytherapy or External Beam Radiotherapy (EBRT) followed by brachytherapy boost. All patients received High dose rate (HDR) interstitial brachytherapy. The total dose was 35 Gy in ten fractions for brachytherapy alone. Patients who received EBRT (50-54 Gy) were boosted by brachytherapy to a dose of 18-24 Gy in 6-8 fractions. All patients were treated using CT based planning.

RESULTS

Between 2007 to 2017, a total of 24 patients of Carcinoma Buccal Mucosa received HDR interstitial brachytherapy either alone or as a boost. Majority of the patients were tobacco chewers (80%). 17(71%) patients were clinical stage T2N0M0 and 7(29%) were clinically T1N0M0. At a median follow up of 7 years (3-12 years), the local control rate was 100% in stage I and 88% in stage II. The 5 year overall survival rate was 80%. Two patients developed nodal recurrence and one patient developed distant metastasis within two years of treatment. Tumor size and brachytherapy technique (radical vs. boost) did not impact local control or overall survival (p > 0.05). Majority of the acute toxicities were Grade 1 and 2. One patient developed osteoradionecrosis of the mandible.

CONCLUSIONS

Interstitial brachytherapy in early-stage Buccal Mucosa cancer either alone or as a boost provides excellent long term local control and overall survival. The acute and late toxicities are acceptable with majority of the patients presenting with Grade 1 or 2 toxicity.

Brachytherapy for Oral Cavity Cancers in the Era of Intensity-Modulated Radiotherapy: Save it or Shelve it

Head and neck cancer treatment includes a multidisciplinary approach involving all specialties. Surgery and radiotherapy are equally effective in controlling small tumors. Intensity-modulated radiotherapy (IMRT) and interstitial brachytherapy (ISBT) play an important role in the treatment of head and neck cancers. Both are proved to be highly conformal techniques of radiotherapy. Our aim is to compare dosimetric aspects of ISBT alone, IMRT alone, and IMRT combined with ISBT in early stage node negative oral cavity cancer. Ten cases of histopathologically proven early stage node negative oral cavity cancer were treated with external beam therapy followed by interstitial brachytherapy boost or ISBT alone. All these patients had undergone computerized tomography (CT) planning for brachytherapy. Retrospectively, these images were utilized, and three sets of plans were done for each patient's CT image set. Group A was IMRT alone plans, groups B had combined IMRT with ISBT boost, and group C was ISBT alone plans. Dosimetric details such as target coverage, dose to critical organs, and conformity index were compared between the three sets of plans. The mean values of the doses to the critical organs with IMRT alone and IMRT with ISBT boost were brainstem 10.40 Gy and 9.20 Gy, spinal cord 19.20 Gy and 16.10 Gy, mandible 62.99 Gy and 66.50 Gy, and I/L and C/L parotids were 6.03 Gy and 5.50 Gy and 5.70 Gy and 5.10 Gy where as in ISBT alone plans mean values were brainstem 1.30 Gy, spinal cord 1.40 Gy, mandible 36.50 Gy, I/L, and C/L parotids were 1.60 Gy and 1.00 Gy. Conformity index (CI) between IMRT and ISBT plans were 0.8580 and 0.7140 respectively. With comparable CI values, doses to critical organs appear to be in favor of ISBT plans as opposed to IMRT, and this was found to be statistically significant. Brachytherapy shows a dosimetric advantage over IMRT in this setting and could be translated to a benefit in terms of toxicities, organ preservation, and cosmesis in the actual clinical scenario. However, whether this would translate to significant benefit in terms of clinical outcome needs to be still verified.

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.

Adjuvant interstitial three-dimensional pulse-dose-rate-brachytherapy for lip squamous cell carcinoma after surgical resection

Purpose

The purpose of this study was to report clinical outcomes of patients treated with pulse-dose-rate brachytherapy (PDR-BT) for lip cancer after insufficient surgery.

Material and methods

Twenty lip cancer patients were treated from January 2012 to September 2016. Primary treatment included surgery with or without reconstruction. All patients were diagnosed with squamous cell carcinoma, most of the tumors were pT1. Brachytherapy procedures were done after post-operative wound healing. Median of three plastic tubes were implanted using a free-hand technique. Two PDR-BT treatments were scheduled for every patient, with the gap of median 13 days. The planned dose was 0.8-1 Gy per pulse to the total dose of 50 Gy from two PDR-BT treatments. Patients were evaluated every 3-6 months. Follow-up time was counted from the last day of treatment to any event or last visit. Early and late toxicities were scored with RTOG scale.

Results

Average follow-up was 34.7 months (range, 12.7-67.6). Three- and five-year estimated disease-free survival was 95% and local control was 100%. One patient suffered from regional relapse in the submental region (IA lymph node group). Skin erythema or dry desquamation (grade 1) or wet desquamation (grade 2) was observed in 13 patients (65%) and one patient (5%), respectively. Six patients presented no acute toxicity. Moreover, there were no complications involving lip mucosa. All patients had grade 1 soft tissue fibrosis in the irradiated area, besides that, late toxicity included only skin complications. There were no significant factors associated with late toxicity ≥ grade 2.

Conclusions

PDR-BT in the adjuvant treatment of the lip cancer yields high local control with low toxicity. Even patients with close margins after surgery (< 5 mm) should be considered as candidates for PDR-BT.

Image guided high-dose-rate brachytherapy versus volumetric modulated arc therapy for head and neck cancer: A comparative analysis of dosimetry for target volume and organs at risk

Background The aim of the study was to present dosimetric comparison of image guided high-dose-rate brachytherapy (IGBT) with volumetric modulated arc therapy (VMAT) for head and neck cancer regarding conformity of dose distribution to planning target volume (PTV) and doses to organs at risk (OARs). Patients and methods Thirty-eight consecutive patients with T1-4 mobile tongue, floor of mouth and base of tongue cancer treated with IGBT were selected. For these patients additional VMAT treatment plans were also prepared using identical computed tomography data. OARs and PTV related parameters (e.g. V98, D0.1cm3, Dmean, etc.) were compared. Results Mean V98 of the PTV was 90.2% vs. 90.4% (p > 0.05) for IGBT and VMAT, respectively. Mean D0.1cm3 to the mandible was 77.0% vs. 85.4% (p < 0.05). Dmean to ipsilateral and contralateral parotid glands was 4.6% vs. 4.6% and 3.0% vs. 3.9% (p > 0.05). Dmean to ipsilateral and contralateral submandibular glands was 16.4% vs. 21.9% (p > 0.05) and 8.2% vs. 16.9% (p < 0.05), respectively. Conclusions Both techniques showed excellent target coverage. With IGBT dose to normal tissues was lower than with VMAT. The results prove the superiority of IGBT in the protection of OARs and the important role of this invasive method in the era of new external beam techniques.

American Brachytherapy Society Task Group Report: Combined external beam irradiation and interstitial brachytherapy for base of tongue tumors and other head and neck sites in the era of new technologies

Irradiation plays an important role in the treatment of cancers of the head and neck providing a high locoregional tumor control and preservation of organ functions. External beam irradiation (EBI) results in unnecessary radiation exposure of the surrounding normal tissues increasing the incidence of side effects (xerostomy, osteoradionecrosis, and so forth). Brachytherapy (BT) seems to be the best choice for dose escalation over a short treatment period and for minimizing radiation-related normal tissue damage due to the rapid dose falloff around the source. Low-dose-rate BT is being increasingly replaced by pulsed-dose-rate and high-dose-rate BT because the stepping source technology offers the advantage of optimizing dose distribution by varying dwell times. Pulsed-dose and high-dose rates appear to yield local control and complication rates equivalent to those of low-dose rate. BT may be applied alone; but in case of high risk of nodal metastases, it is used together with EBI. This review presents the results and the indications of combined BT and EBI in carcinoma of the base of tongue and other sites of the head and neck region, as well as the role BT plays among other-normal tissue protecting-modern radiotherapy modalities (intensity-modulated radiotherapy, stereotactic radiotherapy) applied in these localizations.

Clinical outcome of high-dose-rate interstitial brachytherapy in patients with oral cavity cancer

Purpose

To evaluate the clinical outcome of high-dose-rate (HDR) interstitial brachytherapy (IBT) in patients with oral cavity cancer.

Materials and Methods

Sixteen patients with oral cavity cancer treated with HDR remote-control afterloading brachytherapy using ¹⁹²Ir between 2001 and 2013 were analyzed retrospectively. Brachytherapy was administered in 11 patients as the primary treatment and in five patients as salvage treatment for recurrence after the initial surgery. In 12 patients, external beam radiotherapy (50-55 Gy/25 fractions) was combined with IBT of 21 Gy/7 fractions. In addition, IBT was administered as the sole treatment in three patients with a total dose of 50 Gy/10 fractions and as postoperative adjuvant treatment in one patient with a total of 35 Gy/7 fractions.

Results

The 5-year overall survival of the entire group was 70%. The actuarial local control rate after 3 years was 84%. All five recurrent cases after initial surgery were successfully salvaged using IBT ± external beam radiotherapy. Two patients developed local recurrence at 3 and 5 months, respectively, after IBT. The acute complications were acceptable (≤grade 2). Three patients developed major late complications, such as radio-osteonecrosis, in which one patient was treated by conservative therapy and two required surgical intervention.

Conclusion

HDR IBT for oral cavity cancer was effective and acceptable in diverse clinical settings, such as in the cases of primary or salvage treatment.

Role of high dose rate interstitial brachytherapy in early and locally advanced squamous cell carcinoma of buccal mucosa

Background

The study aimed to assess the effect of High Dose Rate (HDR) Interstitial Brachytherapy when used alone or in combination with External Beam Radiotherapy (EBRT), in early and locally advanced squamous cell carcinoma of buccal mucosa.

Materials and methods

Thirty three patients with histologically proven squamous cell carcinoma of the buccal mucosa received high dose rate interstitial brachytherapy either as primary treatment or as a boost from November 2008 to April 2013. Stage I patients received interstitial brachytherapy alone to a dose of 38.50 Gy, 3.5 Gy per fraction, twice daily at six hours apart for 11 fractions. Stage II patients received EBRT to a dose of 50 Gy in 25 fractions of two Gy each followed by brachytherapy boost to 21 Gy, 3.5 Gy per fraction, twice daily at six hours apart for six fractions. Stage III patients received the same radiotherapy schedule (i.e., same EBRT & Brachytherapy schedule) and with addition of Injection Cisplatin 70 mg/m² in three divided doses every three weeks along with EBRT.

Results

Follow up ranged from 12 to 60 months, median follow up was 26 months. Complete response was observed in 28 patients. Five patients had residual disease and were referred for surgical salvage. One patient died of disease progression. Stage I patients had 100% local control, whereas Stage II and Stage III patients had 84.6% and 80% local control respectively.

Conclusion

HDR Interstitial Brachytherapy used either as a primary treatment modality or as a boost in buccal mucosal cancers provides results comparable to that of surgery, with the advantages of organ preservation, better cosmetic and functional outcomes.

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.