| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
Head and Neck Imaging |
1 From the Department of Radiology, University Hospitals, Herestraat 49, B-3000 Leuven, Belgium (R.H.); the Department of Radiology, the Netherlands Cancer Institute, Amsterdam (F.A.P.); and the Departments of Radiology (A.A.M.) and Radiation Oncology (J.T.P., W.M.M.), University of Florida College of Medicine, Gainesville. Received March 5, 1999; revision requested April 8; revision received May 19; accepted June 29. Address reprint requests to R.H. (e-mail: robert.hermans@uz.kuleuven.ac.be).
 |
Abstract |
|---|
 TOP Abstract IntroductionMATERIALS AND METHODSRESULTSDISCUSSIONReferences |
|---|
MATERIALS AND METHODS: Pre– and post–radiation therapy follow-up CT scans in 66 patients were reviewed retrospectively. All patients underwent definitive hyperfractionated radiation therapy and were followed up clinically for at least 2 years after its completion. Post–radiation therapy CT scans (N = 153) were evaluated for posttreatment changes with a three-point score: A score of 1 represented expected posttreatment changes; 2, focal mass with a maximal diameter of less than 1 cm and/or asymmetric obliteration of laryngeal tissue planes; or 3, focal mass with a maximal diameter equal to or greater than 1 cm or estimated tumor volume reduction of less than 50%. All patients underwent the first posttreatment CT study 1–6 months after therapy. New or progressive laryngeal cartilage changes were noted. The clinical impression of the larynx at the time of each follow-up CT scan was also recorded.
RESULTS: In 12 of 29 (41%) patients with treatment failure at the primary site, follow-up CT scans were definite for local failure (score, 3) a mean of 5.5 months (median, 3.5 months; range, 1–17 months) before clinical examination results.
CONCLUSION: In many patients, follow-up CT shows local failure earlier than does clinical examination alone.
Index terms: Head and neck neoplasms, 271.373, 272.373 • Head and neck neoplasms, CT, 271.12112, 271.373, 272.12112, 272.373 • Head and neck neoplasms, therapeutic radiology, 271.1299, 272.1299 • Larynx, CT, 271.12112 • Larynx, neoplasms, 271.373 • Larynx, therapeutic radiology, 271.126
|
Introduction |
|---|
|
TOPAbstractIntroductionMATERIALS AND METHODSRESULTSDISCUSSIONReferences |
|---|
Results of other studies (3–9) suggest that imaging-based identification of patients at high risk for local failure is possible before definitive radiation therapy. In patients identified at triage as having such a high-risk profile, intensive imaging surveillance could be added to the already careful clinical follow-up regimen and could lead to earlier salvage surgery in patients who do not respond to treatment. In patients who respond well and in those who have low-risk profiles, cost reductions could be achieved by limiting or eliminating imaging surveillance.
Results of a more recent study (10) show that patients undergoing irradiation for a laryngeal carcinoma can be stratified into risk groups for primary site recurrence on the basis of the findings of posttreatment CT performed during the first 6 months after radiation therapy. A focal laryngeal mass with a diameter equal to or greater than 1 cm or with an estimated tumor volume reduction of less than 50% on such an early posttreatment CT scan is highly predictive of local failure, irrespective of the CT-determined pretreatment risk profile (10).
The purpose of this study was to determine if the application of these CT criteria results in the detection of local failure earlier with follow-up CT than with clinical examination alone.
|
MATERIALS AND METHODS |
|---|
|
TOPAbstractIntroductionMATERIALS AND METHODSRESULTSDISCUSSIONReferences |
|---|
All patients were treated with hyperfractionated, continuous-course radiation therapy twice daily for a total dose of 6,720–7,920 cGy. The treatment techniques have been described previously (12,13). In some patients, radiation therapy was followed by a planned neck dissection. Two patients with a stage T3 piriform sinus carcinoma and with a stage T3 supraglottic carcinoma received neoadjuvant chemotherapy prior to radiation therapy.
The patients were entered into the study when a follow-up CT study was performed 1–6 months after completion of radiation therapy. In some patients, this CT study was planned as part of their follow-up; in others, it was performed because of a symptom that reflected potential local failure.
All patients were followed up clinically for at least 2 years after completion of radiation therapy. No patient was lost to follow-up. The charts of all patients were reviewed by one of the authors (R.H.), and the clinical impression of the larynx at the time of follow-up CT was recorded by using a three-point, post–radiation therapy clinical scale: A score of 1 reflected that results indicated expected post–radiation therapy changes and no evidence of disease; 2, results were suspicious for local recurrence or treatment complication; or 3, results indicated definite local recurrence or treatment complication. If findings of the clinical examination became suspicious or definite for local failure at some other time, this also was noted.
All pre- and posttreatment CT studies were performed during injection of intravenous iodinated contrast material; 3-mm-thick contiguous sections were obtained with the plane of the section parallel to the true vocal cord; the field of view was 12–18 cm, with a matrix of 512 x 512 (14). Prior to 1986, some studies were performed with 5-mm-thick sections.
All CT scans were retrospectively reviewed by two head and neck radiologists (R.H., A.A.M.), who were unaware of patient outcomes. Consensus was reached between the two reviewers for each CT scan.
In three patients, the pretreatment CT scans were not available. The post–radiation therapy CT scans (N = 153) were evaluated for posttreatment soft-tissue changes. If complete resolution of the tumor at the primary site and symmetric-appearing laryngeal and hypopharyngeal tissues were seen, the CT findings were considered to be expected posttreatment changes (posttreatment score of 1) (1); if a focal mass with a maximal diameter of less than 1 cm and/or asymmetric obliteration of laryngeal tissue planes was seen, the CT findings were called indeterminate (posttreatment score of 2); if a focal mass with a maximal diameter of 1 cm or greater or an estimated tumor volume reduction of less than 50% was seen, findings of the CT study were considered definite for local failure (posttreatment score of 3).
Follow-up CT scans were obtained 1–6 months (66 patients, 89 scans), 7–12 months (26 patients, 32 scans), 13–24 months (20 patients, 26 scans), and more than 24 months (five patients, six scans) after the completion of radiation therapy.
The sensitivity, specificity, accuracy, and negative and positive predictive values of follow-up CT for detection of local failure (score of 3) were calculated.
New or progressive laryngeal cartilage involvement, compared with that on the pretreatment CT scan, also was noted. The criteria used for diagnosing involvement of the laryngeal cartilage were asymmetric sclerosis (thickening of the cortical margin and/or increased medullary attenuation at comparison of one arytenoid cartilage to the other or of one side of the cricoid or thyroid cartilage to the other side), lysis (destruction of ossified cartilage), and focal or diffuse soft-tissue changes visible on both sides of the cartilage.
In five patients, the follow-up scans (n = 8) were not available for review; in another patient, one of two follow-up scans was not available. In these patients, classification was performed by reviewing the report made previously by one of the investigators (A.A.M.).
The end point used in the analysis was continuous local control for at least 2 years or local failure (loss of laryngeal function) due to either local recurrence or chondronecrosis that resulted in laryngectomy, permanent tracheostomy, or death.
|
RESULTS |
|---|
|
TOPAbstractIntroductionMATERIALS AND METHODSRESULTSDISCUSSIONReferences |
|---|
Twenty-three patients had local failure because of histopathologically proved tumor recurrence, five patients underwent total laryngectomy for suspected recurrence or for laryngeal necrosis and no tumor was found in the specimen, and one patient died suddenly of severe respiratory distress attributed to laryngeal chondronecrosis.
In 24 of the 29 patients whose tumor was locally uncontrolled, findings of the last follow-up CT examination were classified as having a posttreatment score of 3. In seven patients with local failure, an increase of the posttreatment CT score from 2 to 3 occurred over time (1–6 months after radiation therapy in two; 7–12 months, in two; and 13–24 months, in three).
In five of the 29 patients with local failure, results of the last follow-up CT examination were classified with a posttreatment score of 2. In two of these patients, the last follow-up CT study was performed 11 or 18 months before the diagnosis of tumor recurrence.
No patient with a posttreatment CT score of 1 had a mucosal tumor recurrence at the time of follow-up CT.
In 12 of 29 (41%) of the patients whose tumor was locally uncontrolled, findings of follow-up CT became definite for local failure earlier than those of clinical examination (posttreatment clinical score of 2 or 3). In six of these 12 patients, this radiologic diagnosis was confirmed rapidly with results of biopsy or laryngectomy. In the other six patients, no immediate action was undertaken on the basis of clinical judgment; in these patients, the CT diagnosis of local failure was eventually confirmed, with a mean delay of 5.5 months (median, 3.5 months; range, 1–17 months). In five of these six patients, the delay was because of the paucity of clinical symptoms and/or the fact that no suspicious findings were detectable with direct laryngoscopy at the time of radiologic diagnosis of local failure. In the sixth patient, findings of clinical examination and follow-up CT became simultaneously abnormal 5 months after radiation therapy. However, the findings of the clinical examination were of less concern than those of CT (Fig 1); after two more CT examinations (at 7 and 10 months), both with results definite for local failure, and with positive results of a 2-[fluorine 18]fluoro-2-deoxy-D-glucose (FDG) single photon emission CT, or SPECT, study, biopsy was performed and local recurrence was confirmed histopathologically.
|
|
|
|
Two months after radiation therapy, another patient's CT results were classified with a posttreatment score of 3; however, at CT 5 months after radiation therapy, the patient's focal mass appeared less than 1 cm in diameter (posttreatment CT score of 2). Results of the patient's third follow-up CT examination performed 12 months after radiation therapy again were classified as a post–radiation therapy score of 3; this patient had unremarkable results of clinical examination, remained continuously free of local disease, and died of other disease at 4 years 1 month after radiation therapy.
The sensitivity, specificity, accuracy, and negative and positive predictive values of use of follow-up CT for detection of local failure (posttreatment score of 3) were 83% (24 of 29), 95% (35 of 37), 89% (59 of 66), 88% (35 of 40), and 92% (24 of 26), respectively.
New or progressive laryngeal cartilage alterations (cricoid sclerosis [n = 4], cricoid lysis [n = 2], arytenoid sclerosis [n = 1], arytenoid lysis [n = 4], and thyroid lysis [n = 2]) were seen in eight patients on the follow-up CT scans. Four of these patients had local failure because of tumor recurrence; all of these patients had a posttreatment CT score of 3 when the recurrence was confirmed, while one had a posttreatment CT score of 2 when the cartilage alteration was first noted. The other four patients with progressive cartilage alterations seen on follow-up CT scans developed chondronecrosis (one histopathologically proved). One patient who was shown to have isolated cricoid sclerosis was classified initially as having a posttreatment CT score of 2. This patient's posttreatment CT score was later increased to 3 because of the appearance of a soft-tissue mass with spread beyond the larynx; results of laryngectomy revealed necrosis without evidence of recurrence. Another patient had a necrotic-appearing thyroid lamina surrounded by fluid and gas, with laryngeal tissues with a posttreatment CT score of 3. No immediate action was taken because of the paucity of clinical symptoms and because of the lack of suspicious findings at direct laryngoscopy; this patient died later of sudden respiratory distress that was attributed to laryngeal chondronecrosis. The CT scans of two patients with arytenoid lysis accompanied by cricoid sclerosis were classified repeatedly with a posttreatment score of 2; both patients retained a functional larynx, although one of them needed a temporary tracheostomy; the final diagnosis in these patients was arytenoid chondronecrosis (Fig 2).
|
|
|
|
DISCUSSION |
|---|
|
TOPAbstractIntroductionMATERIALS AND METHODSRESULTSDISCUSSIONReferences |
|---|
Two patients in our series had a persistent local mass on follow-up CT scans that was, on the basis of the defined criteria, definite for local failure but had no evidence of local disease during clinical follow-up. These false-positive findings could be related to focal fibrosis or chronic inflammation. Despite these two false-positive cases, our findings strongly suggest that further exploration in patients with a post–radiation therapy CT score of 3 is warranted, even though deep biopsy could aggravate or initiate necrosis (15). FDG or thallium imaging may prove to be a useful intermediate step in cases where biopsy is considered too risky. Preliminary results of ongoing studies (15–19) suggest that radionuclide imaging can be used to detect local recurrences with a higher accuracy than purely anatomy-based methods, such as CT or magnetic resonance imaging.
Theoretically, a mucosal tumor recurrence may be missed on follow-up CT scans. Such an event, which is likely to be detected with scrupulous clinical examination, was not encountered in this study; none of the patients with a posttreatment CT score of 1 had a mucosal tumor recurrence.
The local outcome in patients with an initial posttreatment CT score of 2 (asymmetric-appearing laryngeal or hypopharyngeal tissues or a focal mass with a diameter smaller than 1 cm) is indeterminate. Our findings suggest that, unless findings of clinical examination already are suspicious for local failure, further follow-up with CT is indicated in these patients.
This study was used to assess specifically whether follow-up CT allows earlier detection of a local failure than clinical examination alone. The results show that follow-up CT can be used to detect about 40% of local failures earlier than with clinical examination.
Use of this imaging-based information could lead to more prompt salvage surgery and could improve the survival rate of these patients. Proof of such a survival benefit requires further study. In a prospective study (20), an improved survival rate following surgery for local recurrence was shown in those patients with less extensive local failure after radiation therapy alone or combined with chemotherapy; these patients underwent biopsy of the original primary tumor site under anesthesia at 8–12 weeks after completion of radiation therapy. The negative predictive value of a biopsy result for local control was reported to be 70% in that study (20). The authors of that study support routine reassessment with biopsy 8–12 weeks after completion of radiation therapy to detect recurrence as early as possible. Results of the current study suggest that use of follow-up CT could reduce substantially the number of patients needing biopsy; furthermore, CT could be used to target biopsy to the area most radiologically suspect.
It is important to note that, in this retrospective setting, no strict follow-up protocol with repeat CT studies was followed. In two patients with local failure, the last follow-up CT scan classified with a posttreatment CT score of 2 was obtained at 11 or 18 months before the diagnosis of tumor recurrence. It is not clear why no further follow-up CT studies were performed in these patients; in a prospective setting, local failure may have been detected earlier with further CT surveillance.
New or progressive laryngeal cartilage alterations after radiation therapy were associated with local failure in six of eight patients. These cartilage alterations can occur without a focal mass with a diameter of at least 1 cm, and in two of our patients with such findings the larynx was retained and was functional. The cartilage changes in these two patients were thought to be because of limited, predominantly arytenoid chondronecrosis, without structural collapse of the laryngeal framework (21). It seems justified to adopt a wait-and-see policy in the subgroup of patients with progressive arytenoid cartilage changes and minimal soft-tissue asymmetry. Close follow-up, both clinical and radiologic, is necessary to detect progressive soft-tissue changes, since such progression is associated with tumor recurrence or severe laryngeal necrosis. FDG positron emission tomography may also be helpful in the distinction of chondronecrosis from local tumor recurrence (22).
The finding on follow-up CT scans of an estimated tumor volume reduction of less than 50% or of a focal mass with a diameter of at least 1 cm after definitive radiation therapy for laryngeal or hypopharyngeal carcinoma indicates a high probability of local failure, and immediate further investigation is warranted.
If the laryngeal tissues appear asymmetric or if a focal mass with a diameter smaller than 1 cm is found, unless findings of clinical examination are already suspicious for local failure, further follow-up CT studies are needed; an interval between studies of 3–4 months is recommended, and CT studies are to be continued up to 2 years after completion of radiation therapy. In a substantial number of cases, local failure of radiation therapy may be detected earlier with CT than with clinical examination alone. These patients with local failure of radiation therapy can then undergo salvage surgery at an earlier stage of local recurrence.
|
Footnotes |
|---|
Author contributions: Guarantors of integrity of entire study, R.H., F.A.P., A.A.M.; study concepts and design, R.H., F.A.P., A.A.M.; definition of intellectual content, R.H., F.A.P., A.A.M.; literature research, R.H., A.A.M.; clinical studies, R.H., A.A.M., J.T.P., W.M.M.; data acquisition, R.H., F.A.P., A.A.M.; data analysis, R.H., A.A.M.; manuscript preparation and editing, R.H.; manuscript review, all authors.
|
References |
|---|
|
TOPAbstractIntroductionMATERIALS AND METHODSRESULTSDISCUSSIONReferences |
|---|
This article has been cited by other articles:
|
|
 |
|
  C. Ferreiro-Arguelles, L. Jimenez-Juan, J. M. Martinez-Salazar, J. L. Cervera-Rodilla, M. M. Martinez-Perez, J. Cubero-Carralero, S. Gonzalez-Cabestreros, M. A. Lopez-Pino, and J. M. Fernandez-Gallardo CT Findings after Laryngectomy RadioGraphics, May 1, 2008; 28(3): 869 - 882. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 J.M. Debnam, A.S. Garden, and L.E. Ginsberg Benign Ulceration as a Manifestation of Soft Tissue Radiation Necrosis: Imaging Findings AJNR Am. J. Neuroradiol., March 1, 2008; 29(3): 558 - 562. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
A.A.K. A. Razek, A.Y. Kandeel, N. Soliman, H.M. El-shenshawy, Y. Kamel, N. Nada, and A. Denewar Role of Diffusion-Weighted Echo-Planar MR Imaging in Differentiation of Residual or Recurrent Head and Neck Tumors and Posttreatment Changes AJNR Am. J. Neuroradiol., June 1, 2007; 28(6): 1146 - 1152. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 V Vandecaveye, F de Keyzer, V Vander Poorten, K Deraedt, H Alaerts, W Landuyt, S Nuyts, and R Hermans Evaluation of the larynx for tumour recurrence by diffusion-weighted MRI after radiotherapy: initial experience in four cases Br. J. Radiol., August 1, 2006; 79(944): 681 - 687. [Abstract] [Full Text] [PDF]
|
|
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| RADIOLOGY | RADIOGRAPHICS | RSNA JOURNALS ONLINE |
months after radiation therapy shows that the tumor has regressed but also shows persistent obliteration of the paraglottic fatty tissue (thin arrows) on the left side, without focal mass. Compare this with the normal-appearing paraglottic fat (thick arrow) on the right side. There was no clinical evidence of disease. This image had a CT score of 2. (c) Image obtained 5 months after radiation therapy shows a focal mass (arrows) with a maximal diameter slightly greater than 1 cm in the original tumor bed. This image had a CT score of 3. Some aspecific left-sided mucosal irregularities were noted at clinical examination. A wait-and-see policy was adopted. (d) Image obtained 10 months after radiation therapy shows progressive extension of the mass (arrows) in the preepiglottic space and ulceration (arrowheads) of the mass at the level of the left false vocal cord. Laryngectomy was performed soon after the last CT study, and results confirmed a local tumor recurrence.
