"Radiation Bronchitis in Lung Cancer Patient Treated with Stereotactic"
UNO ET AL CASE REPORT Radiation Medicine: Vol. 21 No. 5, 228–231 p.p., 2003 Radiation Bronchitis in Lung Cancer Patient Treated with Stereotactic Radiation Therapy Takashi Uno, Takashi Aruga, Koichi Isobe, Ken Motori, Hiroyuki Kawakami, Naoyuki Ueno, and Hisao Ito We report a case of chronic radiation bronchitis that developed in a patient with lung cancer treated with fractionated stereotactic radiation therapy. A 73-year-old woman with a medically inoperable T1N0M0 adenocarcinoma of the lung was treated with stereotactic radiation therapy. By using eight non-coplanar ports, 50 Gy/5 fractions was delivered in two weeks. At four weeks, a partial response was obtained with no acute adverse reaction. She developed severe cough at six months. Fiberoptic bronchoscopy revealed thick circumferentially coated bronchial mucosa in close proximity to the tumor site. At 12 months, follow-up study confirmed marked stenotic change in the B6 segmental bronchus without tumor progression. Key words: lung cancer, radiation bronchitis, stereotactic radiation therapy, hypofractionation INTRODUCTION and cardiovascular disease, thoracic surgeons judged that she was not fit for surgery. Her pulmonary function also T HE LATE EFFECTS OF EXTERNAL BEAM IRRADIATION on the peripheral bronchi are not sufficiently addressed in the literature. Radiation bronchitis is a clinical disease limited the use of external beam radiation therapy of the typical opposing-field technique with elective nodal irradiation. Thus, we decided to treat the primary tumor entity that can be observed when high-dose-rate without regional prophylaxis. Written informed consent endobronchial brachytherapy is applied for airway was obtained. malignancies. We describe a case of chronic radiation bronchitis that developed in patient with early-stage lung Radiotherapy technique cancer treated with stereotactic external beam radiation To improve the conformity of dose distribution, three- therapy using a large fractionated dose. dimensional (3D) stereotactic radiation therapy was planned. Fluoroscopy revealed that the tumor moved at CASE REPORT least 1.5 cm depending on the respiratory phase. Fluoroscopy also confirmed that she could stand for A 73-year-old woman presented with a solitary repeated breath-holds of 12-15 seconds. Thus, to account pulmonary nodule on her chest X-ray film without any for respiratory motion, a deep-inspiration breath-hold remarkable accompanying symptoms. Work-up technique was selected. She was positioned onto the examination including fiberoptic bronchoscopy-guided couch of the CT simulator (AcQSIM PQ2000S, Philips biopsy established adenocarcinoma of the right lung, Medical Systems, Andover, USA) in the supine position T1N0M0, stage I (UICC-TNM, 1997), located in the without a specific immobilization device. CT images right S6. Because she had simultaneous respiratory were acquired in spiral mode using a 1.5 pitch and 3 insufficiency owing to chronic obstructive lung disease mm slice thickness with deep-inspiration breath-holding. Based on the 3D-CT anatomical data obtained, virtual Received June 9 2003; revision accepted July 30, 2003. simulation was performed. Treatment planning and dose Department of Radiology, Chiba University Graduate School of Medicine distribution calculation were done using a 3D treatment Reprint requests to Takashi Uno, M.D., Department of Radiology, planning system (FOCUS, CMS Japan K.K., Tokyo, Chiba University Graduate School of Medicine, Inohana 1-8-1, Japan). The clinical target volume was defined as the Chuou-ku, Chiba City, Chiba 260-8670, JAPAN. visible tumor on each CT slice. In order to create the 228 RADIATION MEDICINE CASE REPORT Fig. 1. Isodose curves of 90%, 80%, 60%, and 40% written on Fig. 2. Follow-up CT findings at 4 months. Tumor shrinkage CT. The 80% dose line encompasses the planning target volume. and surrounding fibrotic lung can be seen. planning target volume (PTV), a 1.0 cm margin was severe cough, which was poorly controlled by given to allow for setup error and organ motion. This continuous use of a narcotic antitussive agent. At 12 1.0 cm margin was presumed to be large enough to months, follow-up bronchoscopy confirmed marked account for any motion in the craniocaudal, lateral, or stenotic change in the B6 segmental bronchus without ventrodorsal direction. Treatment portals were designed tumor progression (Fig. 3B). Repeated debridement via to encompass the PTV with a margin of 0.5-1.0 cm to bronchoscopy resulted in only temporary relief of her allow for beam penumbra. Eight non-coplanar ports were symptoms, with no improvement in the circumferential determined to deliver 50 Gy/5 fractions (every other day) stenosis. At present, 22 months after treatment, she is in two weeks at isocenter using 10 MV photons. Lung- alive with no evidence of local recurrence. density correction was included in the dose calculation. Dose distribution written on CT is shown in Fig. 1. DISCUSSION Before each treatment, anterior-posterior and lateral portal films were taken for verification. Stereotactic irradiation of extracranial tumors is an emerging treatment concept in modern clinical Clinical course radiotherapy. By using multiple non-coplanar beams, At four weeks, partial response was confirmed by follow- radiation dose to the normal tissue surrounding the tumor up CT. Tumor shrinkage with surrounding fibrotic lung can be reduced as far as possible. Limited normal tissue could be detected on the follow-up CT at four months volume in the PTV makes it possible to use a large (Fig. 2). No acute adverse reaction occurred until three fractional dose of 8-12 Gy to a total dose of 30-60 Gy.1-3 months after treatment. She developed severe cough at Primary and metastatic lung tumors are considered six months. Although no progression of the primary typical targets for extracranial stereotactic radiation tumor was observed, bronchoscopy revealed thick therapy. Since it is thought that no lymph node circumferentially coated mucosa in the B6 segmental prophylaxis should be done in cases of clinically bronchus in close proximity to the tumor site (Fig. 3A). uninvolved regional disease,4 the role of this technique Treatment planning CT showed that the lesion was for patients with medically inoperable early stage lung located within the 90% dose area (Fig. 4). Inflammatory cancer is evolving. However, if the PTV margin is large cells, but no cancer cells, were obtained by brush enough, bronchial mucosa adjacent to the tumor may cytology examination. An increase in the white fibrinous also receive this unusually high single dose/fraction, membrane with greater exudation accounted for her which has a potential for late adverse reaction in the Volume 21, Number 5 229 UNO ET AL Fig. 3. Bronchoscopic findings 6 months and 12 months after stereotactic radiation therapy. A) At 6 months, the thick circumferentially coated bronchial mucosa can be seen. B) Marked stenotic change in the segmental bronchus A B (B6) can be detcted at 12 months. normal tissue with low cellular turnover as compared with tumor tissue. Radiation bronchitis is a chronic change in the tracheobronchial tree following high-dose-rate endobronchial brachytherapy for airway malignancies. This disease entity was originally described by Speiser et al. 5 The concept of the hyperdose sleeve may reasonably explain the high dose volume produced by intraluminal brachytherapy sources.6 As for the proximal airway, several series have reported tracheal stenosis after external beam radiation therapy using up to 70 Gy.7,8 Hayakawa et al.9 reported the deleterious effect of 80 Gy in 40 fractions to the proximal bronchi. However, owing to the underlying cartilage, it appears that the trachea and proximal bronchi are more sensitive to the effect of high dose irradiation than the segmental bronchi. Thus, there is no information about the exact tolerance of the segmental bronchi. The most widely used toxicity criteria do not mention radiation bronchitis.10 The fact that it is rarely reported with Fig. 4. A segmental bronchus (B6) is situated within the 90% conventionally fractionated radiation therapy simply dose area. This slice is 6 mm caudal to the slice shown in Fig. 1. means that we are usually operating within the tolerance of the bronchial tissues. Further investigation into the tolerance of peripheral bronchi in this type of radiation was at least 90% of the prescribed dose. Thus, 45-50 therapy, using the concept of biologically effective dose, Gy/5 fractions may be deleterious for the segmental is mandatory. bronchi, although this area is defined as peripheral and In this case, we experienced a severe late bronchial it has been reported that 60 Gy/8 fractions can be safely effect after external beam radiation therapy using administered.11 It should be noted that this was the only hypofractionated stereotactic radiation therapy. As case of radiation bronchitis we experienced among more shown in Fig. 4, the bronchial mucosal dose in this case than 20 lesions treated with this technique. We consider 230 RADIATION MEDICINE CASE REPORT that this uncommon late effect does not outweigh the better radiation treatment of non-small cell lung cancer established value of stereotactic radiation therapy for using new techniques without nodal irradiation. Semin lung tumors. However, our experience suggests that Radiat Oncol, 10: 315–323, 2000. caution should be exercised when stereotactic radiation 5) Speiser BL, Spratling L. Radiation bronchitis and stenosis secondary to high dose rate endobronchial irradiation. Int therapy with a large fractional dose is applied for lung J Radiat Oncol Biol Phys, 25: 589–597, 1993. tumors, especially when the PTV includes segmental 6) Marinello G, Pierquin B, Grimard L, Barret C. Dosimetry bronchi. of intraluminal brachytherapy. Radiother Oncol, 23: 213– 216, 1992. 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