Endotracheal brachytherapy alone: An effective palliative treatment for tracheal tumors

[Tracheal Tumours]

Malignant primary tracheal tumours are rare. The most common histological subtypes are squamous cell carcinoma and adenoid cystic carcinoma. These two entities have different prognoses and growth patterns. Tracheobronchoscopy and thoracic sectional imaging are standard diagnostic tools for tumour staging and local evaluation. Complete surgical resection of the affected tracheal segment is the treatment of choice for limited disease without distant metastases. Incomplete gross tumour resection with additional irradiation is an acceptable therapeutic option for adenoid cystic carcinoma. Interventional endoscopy with tumour debulking or tracheal stenting and/or definitive mediastinal radiotherapy are treatment alternatives in either a locally advanced or palliative setting.

Systematic review of brachytherapy for symptom palliation

PURPOSE

Brachytherapy is most often applied in the curative or salvage setting, but many forms of brachytherapy can be helpful for symptom palliation. Declining utilization is seen, for multiple reasons, such as lack of awareness, insufficient expertise, or poor access to equipment. High level evidence for many types of palliative brachytherapy has been lacking. The objective of the current study was to review the evidence for utilization and efficacy of brachytherapy to palliate symptoms from cancer.

MATERIALS AND METHODS

We performed a systematic search in EMBASE and MEDLINE for English-language articles published from January 1980 to May 2022 that described brachytherapy used for a palliative indication in adults with a diagnosis of cancer (any subtype) and at least one symptom related outcome. Individual case reports and conference abstracts were excluded. All publications were independently screened by two investigators for eligibility.

RESULTS

The initial search identified 3637 abstracts of which 129 were selected for in-depth review. The number of studies (total number of patients) included in the final analysis varied widely by tumor site with the majority (68.2%) involving either lung or esophageal cancer. Despite a limited number of prospective trials that assessed the efficacy of brachytherapy for symptom management, there was a positive effect on palliation of symptoms across all tumor types. There was no clear trend in the number of publications over time. The most commonly cited symptom indications for palliation by brachytherapy were dysphagia, dyspnea, pain and bleeding.

CONCLUSIONS

Brachytherapy can provide palliation for patients with advanced cancer, across different tumor sites and clinical scenarios. However, high level evidence in the literature to support palliative applications of brachytherapy is lacking or limited for many tumor sites. There appears to be a strong publication bias towards positive studies in favor of brachytherapy. Beyond anecdotal reports and individual practices, outcomes research can further our understanding of the role of brachytherapy in palliating advanced cancers of all types, and should be encouraged.

Analysis of dose distribution between contemporary and standard planning in high-dose-rate endobronchial brachytherapy based on three-dimensional imaging

Purpose

The treatment planning (TP) in high-dose-rate (HDR) endobronchial brachytherapy (EB) can be based on various forms of imaging. In the case of lung cancer, one-dimensional or two-dimensional imaging is standard. The dose coverage of the target (planning target volume – PTV) and organs at risk (OAR) is unknown, because the doses are calculated on the basis of the dose points. In modern brachytherapy, TP can be based on three-dimensional (3D) images. A plan created in this way contains information about the dose distribution in the PTV and OAR. Treatment plans based on standard planning (SP) and contemporary planning (CP) may differ in dose distribution in the patient’s body. Those differences between SP and CP may have an effect on the dose distribution in PTV, OAR and follow-up.

Material and methods

The study involved a group of 31 patients prospectively treated with advanced, inoperable, non-small cell lung cancer. As many as 76 treatment fractions were analyzed. Firstly, the coverage of the PTV parameter in 2D and 3D for V₈₅, V₁₀₀ and V₁₁₅ was analyzed. Secondly, the dosage that OAR would take in was evaluated. In the cases of the heart, spinal cord and esophagus, the examined dosage equaled D_0.1cm³, D_1cm³ and D_2cm³ for each of the structures. Also, heart D₂₀ was examined as well as D₅ for the healthy lung.

Results

The median dose to the target volume was on average 43.33% higher for V₈₅ with the contemporary planning method when compared to standard planning, with statistical significance. This came with the cost of an OAR mean dose increase of 1 Gy in D_0.1cm³ for the heart.

Conclusions

Contemporary TP in EB allows one to adjust the dose distribution for individual clinical situations and allows one to improve clinical target volume (CTV) coverage, increase doses to the OAR and increase overall survival. The use of new methods of treatment plans in EB has significantly increased the follow-up to 21 months in a treated group of patients.

Endobronchial brachytherapy for metastasis from extrapulmonary malignancies as an effective treatment for palliation of symptoms

PURPOSE

Endobronchial metastasis (EBM) originating from primary cancers outside the lung is rare. External beam radiotherapy is often attempted for control of symptoms with variable effectiveness and retreatment is challenging if symptoms recur. There is limited documentation of high-dose-rate brachytherapy for EBM in the literature.

METHODS AND MATERIALS

A prospective database was created from 2006 to 2015. Patients with EBM who received high-dose-rate brachytherapy were included. Cough, dyspnea, chest pain, and hemoptysis were assessed and graded (0-4) at the time of initial consult and in followup. Symptom-free survival and re-expansion were assessed.

RESULTS

Thirty-five patients with EBM were identified. Most patients received three fractions of 700 cGy, and 17 patients had prior external beam radiotherapy. Median symptom-free and overall survival were 67 and 117 days. After brachytherapy, improvement in cough was documented in 75.0%, hemoptysis in 76.4%, dyspnea in 60.0% for a median of 3-6 months. Of the 22 patients who had subsequent chest imaging, re-expansion was documented in 32%. There were no significant toxicities reported.

CONCLUSIONS

Brachytherapy appears effective in achieving durable symptom control of cough hemoptysis, and dyspnea in patients with EBM and should be considered routinely for palliation where available. Further studies are required to better characterize expected symptom improvement, lung re-expansion rates, and efficacy in comparison with other local treatments.

Percutaneous CT-fluoroscopic-guided radioisotope seed placement for the management of adenoid cystic carcinoma of the trachea

PURPOSE

Tracheal and paratracheal malignancies present challenges in radiotherapeutic management due to their proximity to sensitive structures, central location, and because of the potential for catastrophic radiation induced fistula. The use of external beam radiation therapy and intraluminal brachytherapy has a limited number of reports in the literature. We have searched for a technique for treating tracheal and paratracheal malignancies allowing application of a high dose of radiation while minimizing dose to normal tissues. Our group has considerable experience in the use of percutaneous CT-guided radioisotope seed implants for intrathoracic malignancies. We have previously reported our technique for percutaneous CT-fluoroscopic-guided radioisotope seed implants in the management of thoracic malignancies. We have now treated several tracheal and paratracheal malignancies with our technique and report our results here. This is to our knowledge the first report of treatment of tracheal malignancy with CT-guided permanent seed implant.

METHODS AND MATERIALS

Three patients with tracheal adenoid cystic carcinoma were implanted with ¹⁰³Pd under CT-fluoroscopic guidance utilizing percutaneous approach.

RESULTS

All patients tolerated the procedure well, and at 9-month average followup, all show disease regression, symptom improvement, and no sign of toxicity.

CONCLUSIONS

We believe this to be the first published series on CT-directed permanent seed brachytherapy for tracheal malignancies. Review of PubMed literature to 1990 discloses no prior writings on the use of permanent seed implantation for tracheal cancers. Tracheal malignancies provide a vexing radiation therapy challenge to stay within the therapeutic window. CT-directed permanent seed brachytherapy allows a high dose to be delivered to the tumor with a rapid falloff to the surrounding tissues. Short-term results from seed implant are excellent. Our 3 patients responded well in the short term to permanent seed brachytherapy with no chronic side effects and with reduction or relief of cough and pain. CT-fluoro-guided permanent seed implantation is an effective and low morbidity treatment for tracheal malignancies. Long-term followup is needed to further elucidate durability of response and toxicity.