A new parameter of ultrasonic measurement for follow-up of choroidal metastasis
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首席医学网
2007年08月31日 20:31:38 Friday
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作者：Nadir A M Ali 1, S C Reddy 1, Christina Ng 2, V Subrayan 1 作者单位：1 Department of Ophthalmology, 2 Department of Oncology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
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Abstract AIM: To report the usefulness of a new parameter (maximum cross sectional area) in the measurements of B-scan ultrasonography to evaluate the progress of choroidal metastatic tumour size during the follow-up of patient. METHODS: Case report—the B-scan ultrasonographic measurements of height, base and maximum cross sectional area during the follow-up of the patient are presented. RESULTS: A 62-year-old Chinese lady, known case of non-small cell lung carcinoma, presented with painless blurring of vision in the right eye. She was diagnosed to have bilateral choroidal metastasis (advanced in the right eye and early in the left eye) with good vision in both eyes. The tumour size in the right eye reduced significantly after the first chemotherapy; but increased again 6 weeks after the end of last cycle of chemotherapy. She was given radiotherapy and another course of chemotherapy. The tumour size in the right eye did not respond much later on. However, the tumour size in the left eye was static through out the follow up period of 2 years. The patient maintained best corrected visual acuity in both eyes (6/9 in right eye and 6/6 in left eye). The progress of tumour size in right eye was evaluated with serial B-scan ultrasonographic measurements. CONCLUSION: The ultrasonographic measurements were reproducible all through the follow up period and coincided well with clinical appearance of the tumour in right eye. We suggest the use of B-scan ultrasonography in the follow up of patients with elevated choroidal masses for quantitative assessment of progression/regression in their size during the treatment period.
· KEYWORDS: choroidal metastasis; lung carcinoma; ultrasonography; maximum cross sectional area
INTRODUCTION
Choroidal metastasis is diagnosed clinically by the appearance of the lesion in binocular indirect ophthalmoscopic/slit lamp biomicroscopic fundus examination and the presence of malignancy in some part of the body. The diagnosis can further be supported by the B-scan ultrasonography of the eye. The progress of the lesion can be appreciated by serial follow up fundus photographs taken with digital fundus camera or its appearance on B-scan ultrasonography. Majority of the practicing ophthalmologists may not have the facility of digital fundus camera for this purpose. However, they will have the facility of ultrasound machine which is essential for doing cataract surgery (A-scan) and for evaluating the posterior segment in cases of opaque media (B-scan).
Measurement of base and height of choroidal tumours using B-scan ultrasonography was well documented in literature[1,2]. We report a case of bilateral choroidal metastasis in a patient of non-small cell lung carcinoma which was followed up by B-scan ultrasonography. A new parameter of ultrasonographic measurement, maximum cross-sectional area (MCSA), was used in follow up in addition to the conventional base and height. We feel this can be practiced easily by all ophthalmologists. To the best of our knowledge, this is the first report of 'maximal cross-sectional area' as a sensitive parameter for measuring choroidal metastases.
CASE REPORT
A 62 years old, non-smoker Chinese housewife was referred from oncology clinic on 2004-06-21 for painless blurring of vision in the right eye for the past 3 months. She was diagnosed to have histologically proved non-small cell lung carcinoma (excision biopsy) in a private corporate hospital in Penang in April 2002. Baseline CT scans of chest/ abdomen/pelvis done in May 2004, showed a 1.9cm×1.1cm lower lobe mass in the right lung, and 3.5cm×2.3cm left adrenal mass. She was started on 6 cycles of 2-drug chemotherapy regime (carboplatin and gemcitabine HCl "gemzar") in May, 2004.
On presentation, the visual acuity was 6/12 in right eye, best correctable to 6/9 with +3.00D, and 6/9 in left eye, best correctable to 6/6 with +3.50D. The anterior segments were normal in both eyes; intraocular pressure was 18mmHg in both eyes. Slit lamp biomicroscopic/binocular indirect ophthalmoscopic fundus examination showed a large choroidal mass in the right eye at the temporal retina with adjacent retinal detachment. There was a small choroidal mass in the left eye temporal to the macula. B-scan ultrasonography of the right eye showed large temporal mass with adjacent retinal detachment and underlying choroidal thickening (Figure 1). However, the lesion could not be demonstrated in the B-scan of the left eye because it was not elevated.
She was followed up in each of her visits to oncology department. Routine slit lamp examination and B-scan measurements of the tumour were done in each visit. The section with the maximal height was first captured, then measurement of the height (H) and base (B) in millimeters, and the maximal cross-sectional area (MCSA) in square millimeters were done for each visit (Figure 2).
After finishing three cycles of chemotherapy, CT scans of the chest, abdomen and pelvis were repeated. The lower lobe mass in the right lung was no more seen, while the left adrenal mass remained unchanged. CT scans were repeated again at the end of the 6 chemotherapy cycles. The systemic disease was noted to be stable when compared with the previous CT scans.
The tumour in the right eye responded well to the chemotherapy course, and it appeared smaller clinically; vision in the right eye was stable (6/9 with glasses). The intraocular pressure in the right eye ranged between 14 and 18mmHg. The tumour in the left eye was static with good vision (6/6 with glasses). However, the tumour mass in the right eye started increasing in size 6 weeks after the completion of six cycles of chemotherapy course, which is evident from the ultrasonic measurements (Table 1).
The condition was discussed with the oncologist, and it was decided to give a trial of external beam radiotherapy. A total dose of 2 000cGy divided into 5 doses (400cGy each) was given in February, 2005. After finishing radiotherapy, only slight reduction in size was noted clinically and ultrasonographically in the right eye. However, the left eye's tumour remained static clinically. Two weeks after the end of radiotherapy, the tumour size had clinically increased in the right eye, which was confirmed by B-scan ultrasonography (MCSA=101.66mm2). The tumour size in the left eye was static clinically.
Since there was increase in the size of the tumour in the right eye inspite of radiotherapy, it was decided (after discussion with the oncologist) to give a single-drug (Decotaxel) chemotherapy course over 18 weeks. The size of the choroidal mass was followed up ultrasonographically. The vision in the right eye during the second chemotherapy course was stable (6/9 with glasses). The intraocular pressure ranged between 11 and 14mmHg in the right eye. The response of the tumour size during the course of the second chemotherapy was found to be not as good as that of the first one (Table 2).
Six months after the second chemotherapy course, the tumour in the right eye was noted clinically to erode through the retina as vitreous seeding was observed in slitlamp biomicroscopy fundus examination. However, retina was still flat and macula appeared normal, and she maintained the initial visual acuity (6/9). The erosion of the surface of the tumour into the vitreous (irregular surface) was visible ultrsonographically also (Figure 3), when compared to the appearance of the same at the time of presentation.
Another chemotherapy course was offered to the patient, but she refused for financial reasons. She was then treated palliatively until she passed away on 2006-06-24 (two years after initial diagnosis).
DISCUSSION
During the follow up of this patient, B scan ultrasonographic measurements were reproducible, and corresponded well with both the ocular and systemic clinical progress. A study done by Collaborative Ocular Melanoma Study Group (COMS) showed that ultrasonographic measurements of choroidal tumours were much nearer to the histopathological measurements than clinical measurements.3 The aim of this case study is to assess the accuracy of maximal cross-sectional area (MCSA) as compared to the base and height in the evaluation of choroidal masses.
The response to chemotherapy in the size of metastatic tumour in the left eye could not be appreciated clinically; probably due to its small size and lack of elevation. Thus, we were unable to appreciate the change in the size of the tumour clinically at presentation and after chemotherapies. A minimum height of 0.75mm is needed for a choroidal mass to be seen in B scan[4]. Hence we were not able to document the tumour ultrasonographically in the left eye.
A comparison between the three ultrasonographic parameters (height, base and MCSA) measured throughout the two-year follow up period for this patient is demonstrated in Figures 4, 5 and 6.
Figure 1 B-scan of the right eye done at presentation showing the tumour (white arrow) with adjacent retinal detachment and choroidal thickening (black arrow), the maximal cross-sectional area was plotted and measured as shown above
Figure 2 After six cycles of chemotherapy-B-scan measurements taken showing the height (a) shown with horizontally put + + marks, the base (b) shown with vertically put + + marks, and the maximal cross-sectional area (c) as a line drawing around the mass
Figure 3 B scan of the right eye done after the end of second chemotherapy showing the irregular surface of the tumour confirming its erosion into the vitreous
Figure 4 Apical height (mm) during the follow up period of two years
Figure 5 Tumour base (mm) during the follow up period of two years
Figure 6 Maximum cross-sectional area (mm2) during the follow up period of two years
a) Clinically the tumour appeared largest at presentation, this can clearly be demonstrated in Figures 4 and 6 but not in Figure 5; b) It then dramatically reduced in size in response to the first chemotherapy course reaching its smallest size at the end of it, again this can clearly be demonstrated in Figures 4 and 6 but not Figure 5; c) It almost reached back its initial size after giving the radiotherapy, clinically, at this point the tumour showed its second peak. This peak is best demonstrated in Figure 6. In Figure 4 this rise in size was shown, but it was not the second highest peak along the course of progression. In Figure 5 this time point was inconsistent with the clinical findings; d) The second chemotherapy course has caused only slight reduction in size clinically as compared to the first chemotherapy course. At the end of the course, the tumour size was slightly lesser than the size at the beginning of the course. This reduction is demonstrated in Figure 6, but not in Figure 4. In Figure 5 this reduction from point (c) can be appreciated, but the point forms the trough of the whole chart which is inconsistent with the clinical course; e) Six months after the end of the second chemotherapy course, the tumour was clinically larger in size and it eroded through the retina to cause vitreous seeding. This size increase is seen in Figures 5 and 6, but not in Figure 4.
Both height and maximal cross-sectional area correlated well with clinical events in the follow up of choroidal metastases in the right eye. The latter is more sensitive than height in monitoring changes in the size of a choroidal tumour. They also demonstrated corresponding decrease in the size of the tumour when the systemic metastasis in the right lung decreased in size. In our study, measurement of tumour base was not reliable in the follow up of choroidal tumour. We feel that follow up of choroidal tumour size can be evaluated easily with B-scan ultrasonographic measurements, especially with maximal cross-sectional area parameter. A case series study is needed to confirm the statistical significance of this new ultrasonographic parameter in the evaluation of progression/regression of choroidal metastasis during the follow up period.
【参考文献】
1 Sobottka B, Schlote T, Krumpaszky HG, Kreissig I. Choroidal metastases and choroidal melanomas: comparison of ultrasonographic findings. Br J Ophthalmol ,1998;82:159-161
2 Redinova M, Barakova D, Sach J. Correlation of ultrasound and biopsy measurements of the size of intraocular tumors. Cesk Slov Oftalmol ,2003;59:40-44
3 Byrne SF, Green RL. Ultrasound of the eye and the orbit (second edition). Intraocular tumours - tumour biometry. Mosby ,2002:123
4 Ossoinig KC. Standardized echography: Basic principles, clinical applications and results. Int Ophthalmol Clin ,1974;19:128
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