Minimally Invasive Tumor Therapy (MITT)

Department of Radiology, Charité – Universitätsmedizin Berlin

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References

  1. Collettini F, Schnapauff D, Poellinger A, Denecke T, Banzer J, Golenia MJ, Wust P, Gebauer B. Perkutane CT-gesteuerte Hochdosis-Brachytherapie (CT-HDRBT) von primären und metastatischen Lungentumoren in nicht chirurgischen Kandidaten; Fortschr Röntgenstr 2012; 184(4): 316-323, DOI: 10.1055/s-0031-1299101.
  2. Ricke J, Wust P, Hengst S, Wieners G, Pech M, Herzog H, Felix R. CT-guided interstitial brachytherapy of lung malignancies. Technique and first results. Radiologe. 2004 Jul;44(7):684-6.
  3. Ricke J, Wust P, Wieners G, Hengst S, Pech M, Lopez Hänninen E, Felix R. CT-guided interstitial single-fraction brachytherapy of lung tumors: phase I results of a novel technique. Chest. 2005 Jun;127(6):2237-42.
  4. Peters N, Wieners G, Pech M, Hengst S, Rühl R, Streitparth F, Lopez Hänninen E, Felix R, Wust P, Ricke J. CT-guided interstitial brachytherapy of primary and secondary lung malignancies: results of a prospective phase II trial. Strahlenther Onkol. 2008 Jun;184(6):296-301.

High-Dose Rate Brachytherapy (CT-HDRBT) for the Treatment of Lung Tumors

 

High-dose rate brachytherapy guided by computed tomography (CT-HDRBT) is a form of local radiation treatment for primary and secondary lung tumors (cancer and metastases).

 

CT-HDRBT was jointly developed by radiologists and radiation oncologists of the Charité about a decade ago. It is based on an internal radiation technique that was introduced in the 1980s to deliver radiotherapy during surgery. CT-HDRBT is superior to conventional radiotherapy because it allows precise local delivery of radiation to cancer tissue while sparing surrounding healthy tissue.

 

In our department, we routinely use CT-HDRBT for the minimally invasive treatment of inoperable primary and metastatic lung tumors.

 

How Does CT-HDRBT Work?

 

Brachytherapy is delivered through one or more so-called afterloading catheters, which are tubes that are inserted into the lung tumor through the skin. The afterloading catheters are placed using computed tomography (CT) for guidance. This step is similar to a CT-guided lung puncture or biopsy. Next, a CT scan of the lung is obtained with the catheter in place before a solid source of radiation (iridium-192) is introduced into the catheter and positioned inside the tumor (Figure 1). With the radioactive source inside the tumor, a very high dose can be delivered to cancer tissue while minimizing exposure to the surrounding healthy lung tissue and neighboring organs.

 

CT-HDRBT of a lung tumor takes 2 – 3 hours. Internal radiation is applied for 10 – 50 minutes, depending on the size of the lung tumor. Patients need to be hospitalized for the procedure.

 

Figure 1: Brachytherapy (internal radiotherapy) of a lung tumor with an afterloading catheter. The entire tumor volume (encircled by the inner dark blue line) is irradiated with a dose of 20 Gray (Gy) (dark red line).

 

At the end of treatment, the catheter is removed and the puncture tract is sealed with tissue glue. The procedure is minimally invasive because it requires only small skin incisions (cuts). Our experience shows that most patients tolerate CT-HDRBT very well with local anesthesia and a strong intravenous painkiller. There is no need for general anesthesia. Most lung tumors can be treated with a single session of CT-HDRBT. Only a few patients with very large tumors or many tumor nodules require several sessions of internal radiation therapy. In most patients, CT-HDRBT can be repeated if the tumor starts to grow again or a new tumor develops.

 

What are the Advantages of CT-HDRBT over other Ablation Procedures?

 

CT-HDRBT has some important advantages over minimally invasive techniques that use heat to destroy cancer tissue (thermal ablation techniques like radiofrequency ablation (RFA)).

 

Large tumors cannot be treated with RFA or other thermal ablation techniques. Scientific studies have shown that it is much more difficult to kill all tumor cells with heat when a tumor is larger than 3 cm.

 

CT-HDRBT has no limitations regarding the tumor size that can be treated. Several studies, including studies by our group, suggest that CT-HDRBT is also suitable for the treatment of very large lung tumors. Another drawback of thermal ablation treatment is that it is less effective when a tumor has high blood flow or is close to a large blood vessel (>3 mm in diameter). In these cases, the blood carries away the heat too fast, and the treatment temperature may be too low to effectively destroy the tumor cells. This problem of heat dissipation does not occur with CT-HDRBT. Therefore, high tumor blood flow and nearby larger blood vessels do not affect the success of CT-HDRBT.

 

What are Possible Complications of CT-HDRBT?

 

CT-HDRBT has a very low complication rate. Some possible complications are related to the insertion and positioning of the afterloading catheter(s). The risk of injury to surrounding organs is minimized by using CT to guide the procedure.

 

Brachytherapy lessens radiation damage to healthy tissue. Precise targeting reduces side effects such as skin burns or inflammation of the mucosal lining of the esophagus (esophagitis). The delivery of radiation is planned in such a way as to protect radiosensitive structures like the esophagus or bone marrow.

 

After internal radiation of a very large tumor, the body’s reaction to the dying tissue may cause fever, chills, and nausea. These side effects develop about 4 – 6 hours after the intervention. In most patients, they can be relieved by medications and will disappear after a couple of hours.

 

A typical complication of CT-HDRBT of the lung is the development of a pneumothorax (collection of air between the lung and the chest wall). The air can be drained by inserting a chest tube (also known as a Bülau drain).

 

Aftercare

 

We offer CT-HDRBT in an inpatient setting. You will be admitted to our ward for about 3 – 4 days. You should have a follow-up computed tomography (CT) examination of the lung with contrast as an outpatient 6 – 8 weeks after treatment and then every 3 months. Follow-up CT is performed to assess the success of treatment and to rule out new lung tumors. You can have your follow-up CT examination as an outpatient in our department or elsewhere. If the CT scan is done at another site, we kindly ask you to send us a CD with the images for evaluation.

 

For further information on DT-HDRBT of the lung, please do not hesitate to contact us. We will be happy to answer any questions you may have.

 

  • Contact:

Minimally Invasive Tumor Therapy (MITT)

Charité, Campus Virchow-Klinikum

Department of Radiology

Augustenburger Platz 1

13353 Berlin, Germany

Phone: +49 (0)30/450-557309

Fax: +49 (0)30/450-557947

minimal-invasive-ambulanz@charite.de oder mia@charite.de

 

Case Example

 

Figure 2: CT-HDRBT of an inoperable lung metastasis. The first image, obtained before treatment, shows a large metastasis (> 4 cm) in the right lung (a). The next image shows three-dimensional (3D) treatment planning after CT-guided placement of the afterloading catheter (b). The CT scan obtained after CT-HDRBT treatment shows marked shrinkage of the metastasis (c). A follow-up CT scan, obtained 7 months later, shows a recurrence in the treated area (d). This patient had a second CT-HDRBT treatment (e) with successful ablation of the recurrent metastasis (f). (Modified from Collettini et al. (1))