Radiography and CT of the chest in malignant melanoma

(1)

大~放射線홈웰슐誌第25 卷第 2 號 pp. 247 - 251, 1989 Journal of Korean Radiol앵ical Society, 25121 247 - 251, 1989

Radiography and CT of the Chest in Malignant Melanoma

Kyu H. Choi

,

M.D:

,

Michael A. Mckusick

,

M.D.

,

Andrew C. Wilbur

,

M.D.

Adam E. Flanders

,

M.D.

,

Water S. Tan

,

M.D.

Department of Radiology, University of Illinois Medical Center

〈국문초록〉

악성 흑색종 환자에서의 흉부 X선 촬영과 전산화 단층촬영의 비교

가올릭대학 의학부 방사선파학교실

최 규 호

지난 3 년동안조직학적으로확진된 악성 흑색종환자 21영에서 펴l전이를평가하기 위하여 단순 흉부 X선 촬영， 흉부 X선 단층촬영파 흉부 전산화 단층촬영을 시챙하여 각각의 유용성을 비교검 토하였다.

원말종양을 제거하기 천에 촬영한 흉부 X선 단순안층딸영과 흉부 전산화단층촬영도 시 챙하였 으나 폐 천이를 확인할 수 없었다 . 수울 후 단순 흉부 X선촬영 빛 흉부 전산화단층팔영으로 폐전

이를 추적하여 보았던 바 10 영 (48 %)에서 흉부 전이가 나타났다.

이상의 성적으로 악성 흑색종의 폐전 이 율은 애우 높지마는， 페전이 유우를 평가하기 위하여 원

발종양제거술을시행하기 전에 찍은흉부단순촬영이 정상이연흉부 X선단순단층촬영 및 흉부선

산화 단층촬영이 큰 도움을 주지 옷함을 알 수 았었마.

- Abstract-

A prospective study of twenty.one patients with proven malignant melanoma carried out over the past three years compares the use of plain chest radiographs, conventional linear tomograms and computed tomograms for identification and evaluation of thoracic metastasis. Prior to surgical resection of the primary melanoma all patients had negative high quality chest radiographs. Nineteen patients also had preoperative conventional or computed tomograms which were negative for thoracic metastasls

Follow.up chest radiographs and computed tomograms revealed thoracic metastasis in ten patients (48 %). lt is concluded that although a high percentage of patients with maligant melanoma eventual. ly develop pulmonary metastasis, chest tomographic studies are unlikely to provide clirrically useful new information at the time of preoperative assessment if the preoperative chest radiograph is negatIve

Department of Radiology, University of Illinois 1νedical Center, 1740 West Taylor Street Chicago, IJIinois 60612

• Current Address: Department o[ Radiology, Catholic University Medical College 이 논문은 1989 년 l월 24 일 접수하여 1989년 2월 3일에 채택되었음

Received Jan. 24, Accepted Feb. 3, 1989

(2)

- 大韓放射線훌훌學會誌 : 第 25 卷第 2 號 1989 -

Introduction

Computed tomography (Cf) is at present the most sensitive diagnostic imaging modaIity for detection of pulmonary parenchymal nodules and en- larged mediastinal lymph nodes. The greater sensitivity of CT compared to chest radiography has led several groups of investigators to conclude that chest radiography alone may not be sufficient for early detection of pulmonary metastatic disease in patients with extrathoracic primary malignancies that are likely to metastasize to the lungs

,

lnclu- ding mallgnant melanoma³,1l,13).

The therax is a well-known site of predilection for metastasis from malignant melanoma

,

with an incicence of lung metastasis of 70 % and higher in autopsy series⁸). Other studies have shown that surgical resectability of thoracic melanoma metastais prolngs patient survivaI³•8). Because of these factors, it has been suggested that conventional or computed tomography of the chest should be routine in the initial assessment of Patients with melanoma

,

to increase the liklihood of detecting early metastasis. No increased efficacy of conventional whole lung tomography over chest radiography in a screening role for melanoma metastasis was shown in a study by Curtis et a1⁶), however

,

and the role of screening chest CT for melanoma has not been established.

In order to evaluate the contribution of screening and followup chest tomographic procedures in malignant melanoma, we prospectively studied a group of patients whose chest radiographs were negative for evidence of metastasis at the time of initial diagnosis of melanoma.

Materials and Methods

who also had preoperative chest CT or whole lung tomography constituted the study group. None of the patients had clinical or radiographic evidence of P비monary metastasis at the time of diagnosis The patients ranged in age from 17 to 65 years Eleven patients were male and ten female. Two of the male patients were black, all others were whi- te.

All twenty-one patients had preoperative chest radiographs. Preoperative chet CT was obtained in eight patients; the other eleven patients had conventional whole lung tomograms prior to resection of primary melanoma.

Chest radiography consisted of combined poster- oanterior and lateral views obtained with auto- matic exposure control at 130 kVp. Chest CT was performed with GE 8800 scanner using 10 mm slice thickness and spacing. Linear whole lung tomography was performed at 1 cm intervals in the supme patJent poslt!On.

All twentyone patients havε bεεn followed during the last three years after diagnosis of the primary lesion. In addition to chest radigraphy, 17 patients have had one or more chest CT studies in the followup period. Four patients have been followed with chest radiographs alone.

Metastatic disease developing in the f이 lowup

period was confirmed either by ’ thoracotomy (N3) or by progressive enlargement of lesions on serial radiological studies(N7)

Results

All patients had negative preoperative chest radiographs. In all but two patients the preoperative screening CT and conventional chest tomographic studies were negative for thoracic metastasis. In one case, a 3 cm clinically-palpable axillary nodal metastasis was identified on an Twenty-one patients with biopsy-proven maIi- otherwise normal chest CT. In a second case

,

the gnant melanoma and chest radiographs which were screening CT was falsely positive, demonstrating negative prior to resection of the primary lesion four small nodules confined to one lung and not

- 248-

(3)

- Kyu H. Chα， et al.: Radiography and CT 01 the chest in MalIgnant Melanoma - visible on the chest radiographs. These were sur-

gically resected and found to be granulomas.

Thus, the additional use of screening CT or conventional tomography contributed no greater tr- ue-positive information than the chest radiographs and physical examinations.

Ten of the twenty-one patients eventually developed radiological and clinical evidence of thoracic metastasis during the 3-year followup period.

Metastatic disease involved lung parenchyma alone in four patients

,

lung parenchyma and mediastinum both in three, lung and rib in one, mediastinum alone in one, and rib alone in one.

The average time interval between resection of the primary lesion and diagnosis of the thoracic metastasis was 31 months, with a range of eight months to four years.

The remaining 11 patients have shown no clinical or radiological evidence of thoracic metastasls.

Classification of the primary melanoma acc- ording to Clark’s criteria (9)was possible in seven of the ten patients who developed thoracic metastases: all were Clark’s level III to V. One patient had clinical stage 11 disease at the time of diagnosis. The level and stage of the remaining 2 patients with eventual metastases were not recorded.

CT was superior to either plain chest radiography or linear tomography in the evaluation of the mediastinum. In one case lymh node enlargement in the azygoesophageal recess readily seen on CT was only retrospectively diagnosed on the plain chest film. In another case, masses in the prev- ascular and subcarinal regions easily seen on CT could not be detected on the plain film. In no case was the patients treatment significantly altered by the discovery of mediastinal involvement due to the fact that both of these patients already had intraparenchymal nodules which were apparent on the plain chest film.

Discussion

Many authors³,5,13) have suggested that plain chest radiography alone is insufficient in the evaluation of the thorax for possible parenchymal and mediastinal metastasis in the presence of extrathoracic primary cancer. Full lung conventional and computed toínography have been proven to be more sensitive than the conventional chest radiograph in detecting pulmonary nodules at a cost of diminished specificity. Chang et al l) reported that CT was able to detect 78 % of lung nodules measuring greater than 3 mm whereas conventional tomograms detected only 59 % of the same nodules. In Chang’s series of 25 patients, forty-five percent of pulmonary nodules demon- strated by CT and 66 % of nodules seen on conventional tomograms proved to be metastatic disease. With the conventional plain film of the chest, 90 % of the nodules seen represented metastasis

The chest is the most frequent organ to be lnv- olved with metastatic melanoma and 5-15 % of all cases of pulmonary metastasis and 5 % of metastasis to lungs and mediastinum are due to melanoma⁴). Because the thorax is also the site of predilection for initial systemic relapse in malignant melanoma and early detection of surgically resec- table metastasis prolongs patient survivaI³,8), it is clear that the chest must be carefully evaluated radiographically, not only at the time of baseline study, but also at prudent and realistic intervals with use of the appropriate modality to facilitate proper therapeutic management and patient care.

In spite of the high sensitivity afforded by conventional and computed tomography in the detection of pulmonary and mediastinal nodules, these modalities often fail to have a significant impact on patient management and survival rates⁵,6). In a study by Heaston et af), CT alone altered patient care in only one patient out of a total of 42 Meyer and

St이bach

⁵) ， in examining 53 patients

(4)

- 大韓放射線醫學會誌: 第 25 卷第 2 號 1989 -

with melanoma

,

found that CT did not add any additional information over and above that gather- ed from the plain chest film. In a series of 62 patients with melanoma and negative plain chest films reported by Curtis et a1⁶) , conventional lung tomography yielded negligible new correct infor- matJon.

Our data support the statement of Meyer et a1⁵)

that pretreatment evaluation of asymptomatic patients with malignant melanoma need not include extensive additional radiologic examinations when the chest radiograph is normal.

Based on our experience and that described by the authors cited above

,

we believe that full lung conventional or computed tomograms are not cos- t effective presurgical screening procedures for the detection of early thoracic metastasis in patients with malignant melanoma when plain chest radiography is unequivocall) negative. Although nea- rly half of our patients developed thoracic metata- sis within three years of initial diagnosis, none of them were identified by preoperative tomographic procedures.

There is a paucity of information in the liter- ature regarding optimal timing and frequency of chest radiography after initial resection of primary melanoma. Webb et a1⁴) have stated that chest radiographs should be obtained at not greater than 3 month intervals to insure early detection of metastais. In their study, the period of time between the diagnosis of the primary tumor and radiographic appearance of thoracic metastasis averaged 32 months; this corresponds to our figure of 31 months.

Chen²) has recommended that conventional chest films be obtained at 4-6 month intervals for follow-up of melanoma patients.

Indications for further radiographic work up of the chest in presurgical or follow up cases include:

1) single lung nodule identified on the plain chest film-tomography is useful in these cases to search for additional lung nodules if surgery is planned;

2) reasonable suspicion of mediastinal involvement either clinically or radiographiclly CT is far superior to plain chest radiography and conventional tomography in the evaluation of mediastinal metastasis.

Our data as well as that of others support the contention that in a very practical and realistic sense

,

plain chest radiography at 4-6 month intervals is the appropriate method of follow-up of melanoma patients when the chest film remains normal. Additional tomographic examinations are not only expensive and time consuming but also do not significantly alter the clinical management or longterm survival in the majority of these pa- tJents.

REFERENCES

l. Chang AE, Schaner EG, Conkle DM, Flye MW, Doppman JL, Rosenberg SA: Evaluation of com.

puted tomography in the detection of pulmonary metastases, cancer 43:913^,916, 1979

2. Chen JTT, Dahmash NS, Ravin CE, Heaston DK, Putman, CE, Seigler HF, Reed JD: Metastatic melanoma to the thorax: report of 130 patients, A]R 137.293'298, 1981

3. Gromet MA, Ominsky JH, Epstein WL, Blois MS:

The thorax as the initial site for systemic relapse in malignant melanoma; A prospective survery of 324 patients, cancer 44:776'784, 1979

4. Webb WR, Gansu G: Thoracic Metastasis in malig.

nant melanoma a radiographic survey of 65 pati.

ents, chest 71:176， 18α 1977

5. Meyer JE, Stolbach L: Pretreatment radiographic evaluation of patients with malignant melanoma, cancer 42:125^,126, 1978

6. Curtis AM, Ravin CE, Deering TF, Putman CE, McLoud TC, Greenspan RH: The efficacy of fu.

ll-lung tomography in the detection of early metast- atic Disease from melanoma, radiology 144:27-29, 1982

7. Heaston DK, Putman CE, Rodan BA, Nicholson E, Ravin CE, Korobkin M, Chen JTT, Seigler HF:

(5)

- Kyu H. Choi, et al.: Radiography and CT of the chest in Malignant Melanoma -

Solitary pulmonary metastasis in high-risk mel- 11. Muhm ]R, Brown LR, Crowe ]K: Detection of anoma patients: A prospective comparison of con- pulmonary nodules by computed tomography, A]R ventional and computed tomography, A]R 141: 128:267-270, 1977

169-174, 1983 12. Webb WR: Hilar and mediastinallymph node meta 8. Das Gupta T, Brasfield R: Metastatic Melanoma: A stais in malignant melanoma, A]R 133:805-810,

clinicopathological study, cancer 17:1323-1339, 1979

1964 13. Simeone ]F, Putman CE, Greenspan RH: Detection

9. Clark WH, Frp, L, Bernardino EA, Mihm ME: The of metastic malignant melanoma by chest roent- histogenesis and biologic behavior of primary hu- gen-ography, cancer 39:1933-1966, 1977

man malignant melanoma of the skin, cancer rese- 14. Dwyer A], Reichert CM, Waltering EA, Flye MW arch 29:705-726, 1969 Diffuse pulmonary metastasis in melanoma: radiogr- 10. Schaner EG, Chang AE, Doppman ]L, Conkle DM, aphic-pathologic correlation, A]R 143:983-984,

Flye MW, Rosenberg SA: Comparison of computed 1984

and conventional whole lung tomography in dete- 15. Cahan WG: Excision of Melanoma Metastasis to cting pulmonary nodules: A prospective radiolo- Lung: problem in diagnosis and management, Ann gic-pathologic study, A]R 131.51-54, 1978 Surg. 178:703-709, 1973