Japanese Journal of Clinical Oncology 33:89-92 (2003)
© 2003 Foundation for Promotion of Cancer Research
A Case of Subglottic Carcinoma Effectively Treated with Intraluminal Irradiation Using Low Dose Rate Iridium-192 Thin Wires Combined with External Beam Irradiation
1 Department of Oncological Science (Department of Radiology), Division of Morphological Diagnosis and Less Invasive Therapy, Oita Medical University, Oita and 2 Department of Radiation Oncology, Aichi Cancer Center, Nagoya, Japan
 |
ABSTRACT |
|---|
 TOP ABSTRACT INTRODUCTIONCASE REPORTDISCUSSIONCONCLUSIONREFERENCES |
|---|
Subglottic carcinoma is rare and has a poor prognosis. It is usually treated with surgical resection, external beam irradiation (EBR) and/or a combination of both. Intraluminal irradiation (IR) as a curative treatment for subglottic carcinoma has never been reported. We report a case of subglottic carcinoma in a 66-year-old man, who was effectively treated with IR combined with EBR. IR was conducted using low dose rate iridium-192 thin wires at a subglottic mucosal dose of 5.1–6.0 Gy per fraction, with a total dose of 43.8 Gy in eight fractions. EBR was administered, using cobalt-60 and 6 MV X-rays delivered at 2 Gy per fraction, with a total dose of 66 Gy in 33 fractions. Complete response was obtained without serious complications and no recurrence occurred in the 79-month follow-up period. IR combined with EBR is useful as a potential curative treatment. It should be considered as one of the treatment options for subglottic carcinoma.
|
INTRODUCTION |
|---|
|
TOPABSTRACTINTRODUCTIONCASE REPORTDISCUSSIONCONCLUSIONREFERENCES |
|---|
Primary subglottic carcinoma is rare. It is usually treated with surgical resection, external beam irradiation (EBR) and/or a combination of both (1–3). We present a case of subglottic carcinoma treated with EBR and intraluminal irradiation (IR) using low dose rate (LDR) iridium-192 thin wires. Complete response was obtained without serious complications and there has been no recurrence in the 79-month follow-up period. There are only a few previous reports regarding the use of IR as a palliative treatment for postoperative tracheal stomal recurrence (4–6). To our knowledge, this is the first report regarding IR as a curative treatment for subglottic carcinoma.
|
CASE REPORT |
|---|
|
TOPABSTRACTINTRODUCTIONCASE REPORTDISCUSSIONCONCLUSIONREFERENCES |
|---|
A 66-year-old man complaining of throat discomfort came to our hospital in July 1995. For 3 months, he had been experiencing blood in his nasal discharge when he blew his nose. At the time of presentation, a laryngoscopy demonstrated a subglottic tumor, invading the right vocal cord (Fig. 1). The movement of his vocal cords was intact. A biopsy revealed moderately differentiated squamous cell carcinoma. Clinically, there were no distant metastases and the clinical stage was determined to be T2N0M0 (stage II, 1987 TNM classification). This patient strongly refused surgery; therefore, radiation therapy was chosen as the curative treatment. EBR using cobalt-60 was started in August 1995 and delivered at 2 Gy per fraction, five times a week. The irradiation technique employed was lateral opposed wedged portals. The field size was 6 x 6 cm (Fig. 2), which was sufficient to cover the tumor at the subglottic area. We confirmed that the proximal portion of the tumor was completely included in this radiation field by using a laryngoscope under an X-ray simulator. Regardless of the prescribed dose of 42 Gy in 21 fractions, only a minor response was obtained and there was an obvious residual tumor. Therefore, another treatment method had to be combined with it to obtain a complete response. A broad-based exophytic tumor was localized to the right subglotic wall. However, there was no infiltration to the thyroid, cricoid and tracheal cartilages. The longitudinal diameter of the tumor was estimated as 3 cm by CT image. IR using LDR iridium-192 thin wires (340 MBq, 5 cm in length and 0.3 mm in diameter) was concurrently combined with EBR. The EBR technique was changed to conformational irradiation with a 6 MV Linac X-ray machine to obtain a sophisticated dose distribution (Fig. 3). The IR technique that is usually used in our hospital to treat localized endobronchial cancers (including tracheal cancer) (7,8) was used for this patient. IR was performed using a special silicon catheter, which measured 11 French in external diameter and 35 cm in length. When the inner tube was removed, the portion of the catheter tip that corresponded to the position of the radiation source had two ‘wings’ at 1 and 4.5 cm from the catheter tip (Fig. 4). These ‘wings’ acted as the spacer. A resinous tube was fitted between the catheter and inner tube to prevent the radiation source tube from protruding from the ‘wings’ during the exchange of the inner tube with the radiation source tube. First, during the IR treatment procedure, the catheter was guided to the subglottic space through the nasal cavity under the laryngoscope and then the inner tube was withdrawn. After the tumor had been confirmed to lie between the two ‘wings,’ the radiation source tube was inserted to replace the inner tube and IR was conducted using the manual afterloading method.
|
|
|
|
The proximal ‘wing’ was located just above the vocal cord and the distal ‘wing’ was located under the subglottic tumor, so the radiation source longitudinally straddled the vocal cord and tumor. The medial surface of the tumor partially touched the catheter. Iridium-192 thin wires were used as the radiation source. Four iridium thin wires were inserted into the radiation source tube in parallel. Fig. 5 shows the dose distribution curve for planning target volume in a longitudinal diameter of 4 cm. At each end of such a linear source application, 10% of the active length of the iridium-192 thin wires should be reduced in general. It was 1 cm in total. The irradiation dose was measured taking the subglottic mucosal surface as the reference point (5 mm from the radiation source) and a dose of 5.1–6.0 Gy (mean dose, 5.475 Gy; dose rate, 1.4–2.0 Gy/h) per fraction per week was delivered. A total dose of 43.8 Gy was prescribed in eight fractions over 8 weeks. The treatment time per session ranged from 3 to 3.75 h. Those treatment times were tolerable to the patient. A boost dose of 24 Gy in 12 fractions over 3 weeks was delivered using conformational irradiation. On the day for application of the IR (once a week), this conformational irradiation was skipped (four fractions per week). The total dose of 66 Gy was prescribed in 33 fractions over 7 weeks. At the completion of EBR, there was still an obvious tumor residue. Accordingly, we added five further sessions of IR. The overall number of treatment days was 92. After the completion of the treatment, complete response was obtained with no serious complications. This patient has been undergoing check-ups for 79 months and remains well. A laryngoscopy 79 months after the completion of treatment demonstrated no recurrence (Fig. 6).
|
|
|
DISCUSSION |
|---|
|
TOPABSTRACTINTRODUCTIONCASE REPORTDISCUSSIONCONCLUSIONREFERENCES |
|---|
Subglottic carcinoma is relatively rare in comparison with supraglottic and glottic carcinoma, constituting between 1 and 3.6% of laryngeal cancers. It is defined as a carcinoma arising in the subglottic space, which differs from a glottic carcinoma with subglottic extension. We diagnosed our patient as subglottic carcinoma invading his vocal cord because the space between the tumor and his vocal cord grew larger with the progress of EBR.
The treatments used for subglottic carcinoma have been surgical resection, EBR and/or a combination of both (1–3), but aggressive surgical therapy followed by postoperative irradiation is recommended because this type of tumor has a tendency for extra-laryngeal spread and paratracheal lymph node metastasis (3). For patients who refuse surgical resection and for those for whom surgery is considered to be inappropriate for various reasons, the only treatment option is EBR, although the therapeutic outcomes of EBR alone are not satisfactory (9).
In this case, the tumor response to EBR at the prescribed dose of 42 Gy was far from sufficient as only a minor response was obtained. Therefore, another treatment method had to be combined with it to obtain a complete response. Information on the use of brachytherapy for subglottic carcinoma is extremely sparse. Latham et al. (4), Jones et al. (5) and Schafer et al. (6) reported on the use of IR using an iridium-192 thin wire for postoperative tracheal stomal recurrence of head and neck cancers including subglottic carcinoma. Their patients had already presented distant metastases and their treatments had palliative intent. To our knowledge, this case report is the first regarding the significance of IR as a curative treatment. We performed IR because of the favorable results that we had experienced using IR for localized endobronchial carcinoma (including tracheal carcinoma) (7,8). IR using iridium-192 has become recognized as a method of curative treatment for endobronchial carcinoma only after the advent of thin and highly flexible iridium sources (7–10). We supposed that subglottic carcinoma could be treated similarly to endobronchial carcinoma. In the treatment of localized endobronchial carcinoma, the catheter is inserted via a simplified tracheotomy tube (Mini-trach II, Portex, UK) that has already been inserted through the cricothyroid membrane. This technique is used because it has the advantages of easy catheter manipulation and does not cause vocal cord irritation. In the treatment of subglottic carcinoma, a tracheotomy tube could not be used because of the location of the tumor. We had to insert the catheter via the nasal cavity, but the patient did not cough as much as we had expected from vocal cord irritation.
Complete response was obtained and there has been no recurrence or complications during the 79 months since the completion of treatment. This patient is in good condition. We think that there are two reasons for the absence of complications even given the high irradiation dose (66 Gy in EBR and 43.8 Gy in IR). First, a low dose rate (LDR) of iridium-192 was used in our treatment. Recently, IR using a high dose rate (HDR) of iridium-192 has become very common worldwide. A comparison of HDR and LDR in the treatment of lung cancer has shown, however, that the complication rate with HDR is higher than that with LDR (11). When HDR iridium-192 is used for subglottic carcinoma, the results may be better if the fraction dose is reduced to a level lower than that used in LDR. The second reason for the absence of complications in our patient was that we used a special catheter equipped with ‘wings’ that acted as a spacer in the area corresponding to the position of the radiation source. This spacer was able to keep the radiation source away from the subglottic mucosa and was capable of maintaining a relatively even dose distribution on the mucosa to prevent mucosal complications by minimizing the excessive dose area.
Therapeutic results of EBR alone for subglottic carcinoma are poor. Actually, the radiosensitivity of this reported case was not high. We think that subglottic carcinoma should not always be considered as a form of laryngeal cancer but can often be considered as a subtype of tracheal cancer and application of IR will contribute to the improvement of therapeutic outcomes for subglottic carcinoma. On performing IR, it is very important to use a spacer and the fraction dose should be 5–6 Gy (in the case of using an LDR) to reduce later complications. The proper combination of EBR and IR needs further study.
|
CONCLUSION |
|---|
|
TOPABSTRACTINTRODUCTIONCASE REPORTDISCUSSIONCONCLUSIONREFERENCES |
|---|
We have presented a case of a patient with subglottic carcinoma. IR combined with EBR achieved complete response without serious complications. This treatment method could be considered as one of the treatment options for subglottic carcinoma.
|
FOOTNOTES |
|---|
+ For reprints and all correspondence: Masaki Wakisaka, Department of Oncological Science (Department of Radiology), Division of Morphological Diagnosis and Less Invasive Therapy, Oita Medical University, 1–1 Idaigaoka, Hasama-machi, Oita 879-5593, Japan. E-mail: wakisaka@oita-med.ac.jp
|
REFERENCES |
|---|
|
TOPABSTRACTINTRODUCTIONCASE REPORTDISCUSSIONCONCLUSIONREFERENCES |
|---|
1 Dahm JD, Sessions DG, Paniello RC, Harvey J. Primary subglottic cancer. Laryngoscope 1998;108:741–6.[Medline]
2 Santoro R, Turelli G, Polli G. Primary carcinoma of the subglottic larynx. Eur Arch Otorhinolaryngol 2000;257:548–51.[Medline]
3 Hanna EY. Subglottic cancer. Am J Otolaryngol 1994;15:322–8.[Medline]
4 Latham MM, Smart GP, Hedland-Thomas B, Harper CS. Endoluminal brachytherapy for recurrent laryngeal carcinoma. Australas Radiol 1997;41:357–60.[Medline]
5 Jones RD, Clarkson DG, Symonds RP, McNee SG. An iridium-192 applicator for the treatment of stromal recurrence following tracheostomy for subglottic carcinoma. Br J Radiol 1991;64:270–1.[Medline]
6 Schafer U, Schmilowski GM, Micke O, Mohring R, Willich N. Short communication: a method of brachytherapeutic treatment of tracheal stoma recurrence in head and neck cancer. Br J Radiol 1996;69:348–50.[Abstract]
7 Fuwa N, Matsumoto A, Kamata M, Kodaira T, Furutani K, Ito Y. External irradiation and intraluminal irradiation using middle-dose-rate iridium in patients with roentgenographically occult lung cancer. Int J Radiat Oncol Biol Phys 2001;49:965–71.[Medline]
8 Fuwa N, Ito Y, Matsumoto A, Morita K. The treatment results of 40 patients with localized endobronchial cancer with external beam irradiation and intraluminal irradiation using low dose rate 192-Ir thin wires with a new catheter. Radiother Oncol 2000;56:189–95.[Medline]
9 Haylock BJ, Deutsch GP. Primary radiotherapy for subglottic carcinoma. Clin Oncol 1993;5:143–6.
10 Saito M, Yokoyama A, Kurita Y, Uematsu T, Miyao H, Fujimori K. Treatment of roentgenographically occult endobronchial carcinoma with external beam radiotherapy and intraluminal low dose rate brachytherapy. Int J Radiat Oncol Biol Phys 1996;34:1029–35.[CrossRef][ISI][Medline]
11 Perol M, Caliandro R, Pommier P, Malet C, Montbarbon X, Carrie C, et al. Curative irradiation of limited endobronchial carcinomas with high-dose rate brachytherapy. Results of a pilot study. Chest 1997;111:1417–23.
Received July 12, 2002; accepted November 14, 2002
CiteULike 
Connotea 
Del.icio.us What's this?
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||