Radiation Bronchitis in Lung Cancer Patient Treated with Stereotactic by lzi20217

VIEWS: 16 PAGES: 4

									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
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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

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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

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                                                                                                                 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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 4) Williams TE, Thomas Jr CR, Turrisi III AT. Counterpoint:




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