Radiotherapy for Lung Metastases in a Patient With Ewing Sarcoma

Purpose. To assess the benefit of therapy for multiple lung metastases in a young female patient previously treated with operation, local radiotherapy and chemotherapy. Patient: Lung metastases occurred in a young female patient 13 months after finishing combined treatment of a Ewing sarcoma of the left eleventh rib. Primary treatment had included surgical removal, 51 Gy local radiotherapy and chemotherapy. Method. 20 Gy total dose was applied to the lungs of both sides in two courses with an additional 15 Gy to the mediastinum. Results and Discussion. Complete radiological regression was achieved at the end of therapy which was maintained during the follow-up period of 16 months.


Introduction
Ew ing sarcom a is the second m ost frequent bone tum our am ong children and young adults. Comprises 10± 15% of all bone tum ors. It rarely occurs under the age of 5 or above the age of 30. T he m ale to fem ale ratio is 1.5:1.
Ewing sarcom a arises intram edullary, breaks through the cortex and extend as a soft tissue m ass. V irtually any bone can be the site of the prim ary lesion, but the lower half of the body is m uch m ore frequently involved than the upper half. The frequency of rib involvem ent follows that of the fem ur, the pelvic bones, the ® bula, the hum erus and the tibia. It has a m oderately bad prognosis. 1± 3 D istant m etastases are frequent to the lungs and other bones. Metastatic involvem ent of lym ph nodes occurs in less than 10% of cases. Increasing pain, swelling and fever are the leading clinical sym ptom s.
Plain X-ray with bone and bone m arrow scintigraphy dem onstrate prim ary or secondary skeletal involvem ent. C om puted tom ography (CT ) and M RI are inform ative for the judgem ent of periosteal and the intram edullary extension. 2

D iagnosis
A 29-year-old fem ale patient presented w ith increasing back pain on the left side, effort dysp noea and fever.
C hest X -ray showed a palm -sized supraph renic in® ltration on the left with m inim al pleural effu sion. Laboratory param eters were norm al except for a raised sedim entation rate and leucocytosis. Pneum onia was suspected and antibiotic treatment started but dyspnoea and the level of the pleural effu sion increased. C ytology of the pleural¯uid suggested in¯amm ation but further Xray showed extensive con¯uent rarefaction of the X Ith rib with bone destruction. W hole body bone and bone m arrow scan showed no changes elsewhere.

Prim ary treatm ent
After resection of the involved rib, histopathological exam ination (including im m uno-histochemistry) gave the diagnosis of Ewing sarcom a. Postoperative radiochem otherapy was com m enced in June 1994. T he chemotherapy com prised 6 courses of VIP (200 m g V epeside, 800 m g Ifosfam ide, 60 m g Cisplatin, with U rom itexan rescue). Radiotherapy w as delivered after the ® rst course of chem otherapy (51 Gy locally w ith a high-energy electron beam ). The ® rst course of chem otherapy had to be interrupted because of dysuria. C olony stimulating factor was necessary because of leukopenia after further courses. Com plem entary m ediastinal irradiation was given after a six w eeks interruption, w ith 15 G y m id-plan e were applied via central-sym m etrically positioned, opposed portals in 1.5 Gy fractions.
Prophylactic irradiation of the right hem ithorax was started 4 w eeks after the m ediastinal irradiation. 20 Gy total m id plane dose was applied in 1.5 Gy fractions. T he m ediastinal treated volum e overlapped to its half width with the left and right hem ithorax volum es for increasing the total dose in the m ediastinum . M atching problem s are clinically negligible at these m agnitudes of total dose if applied sequentially to these regions (Fig. 3).
The overall treatment took 23 w eeks including the breaks. Com plete rem ission (plain X-ray and C T) lasted for 16 m onths (Figs 4 and 5).

D iscussion
M etastasising Ewing sarcoma is asso ciated with short term rem ission and survival but pulm onary irradiation m ay prove effective. 4± 9 D ata are available concerning the prophylactic and therapeutic use of pulm onary irradiation in patients with Ewing sarcom a. Prophilactically total doses of 1500± 1800 cGy were applied in 150± 200 cGy daily fractions within 2.5± 3 w eeks. 2,10 D oses of the m agnitude plus chem otherapy resulted in prolonged disease free survival and prolonged survival in the IESS-I study versus chem otherapy alone. 2 Therapeutically the sam e total doses plus local boost were applied to 2000± 2500 cG y 10,11 resulting in com plete plus partial rem ission rates 77% . 11 Pulm onary m etastases w ere inoperable in this young female patient. Prim ary chem otherapy were asso ciated w ith severe side effects, although radiation therapy was w ell tolerated. The left hem ithorax and the lower posterior m ediastinum were irradiated with the aim of achieving therapeutic effect on m anifest m ultiple lesions. N evertheless we did the sam e for prophylactic purposes on the uninvolved right hem ithorax. T he reasons for the choice of this careful, sequential app roach w ere the following: · m ultiple, extensive lesions on the involved left side and therefore palliative aim ; · prim ary com bined treatment was associated with haem atological side effects; · better radiation tolerance of the lung with partial volum e-exposure; and · special im portance of the right lung in the respiratory function in case of m assive contralateral im pairm ent.
Sequential irradiation of the hemithorax on both

Treatm ent of the pulm onary m etastases
She rem ained sym ptom free for 13 months, with com plete rem ission docum ented by CT . After the onset of cough pulm onary m etastases were shown on thoracic X -ray and CT . M ultiple rounded opacities w ere found: paracardic anteriorly 7 cm , retrocardiac 8 cm, lateral to the left hilus 6 cm , in the left apex along the thoracic w all on the pleura 8 cm, and above the arch of aorta along the m ediastinal pleura 3 cm in diam eter. The right lung showed no abnorm ality (Figs 1 and 2). W hole-thorax irradiation was performed in three phases. An effective palliation was the aim of therapy in this case, so the left hemithorax was treated ® rst. After experiencing the very rapid regression of the m ultiple lesions in this site, treatm ent was extended to the neighbouring structures at risk, i.e. m ediastinal and prophylactic right hem ithorax irradiation w as performed in the following two treatm ent phases. 20 G y total m id-plan e dose was applied to the involved left hem ithorax from a telecobalt unit w ith slightly angled anterior and posterior portals using 1.5 G y fractions. T he anterior ® eld w as tilted 10 degrees laterally and the posterior ® eld 15 degrees m edially. T his slight tilting enabled the paravertebral entering of the m edial edge of the posterior portal with respect to the better protection of the spinal cord after previous chem otherapy. T hree weeks later plain X-ray showed com plete rem ission of the metastases on the left side. sides and mediastinum m ay involve m ore m atching problem s than chest irradiation of the tw o sides at the sam e time, but the space of time betw een the treatment phases and the described ® eld arrangem ent contribute to decrease them at low doses. T he outpatient treatment led to radiological com plete rem ission and im provem ent in quality of life without dysp noea. She has been sym ptom free for 16 m onths after ® nishing therapy and is able to pursue som e sport.