| Abstract | Svrha studije bila je utvrditi dijagnostičku korist nalaza dobivenih u prva dva
vremena snimanja kod trovremenske scintigrafije kosti lokalne regije u bolesnika
sa osteogenim sarkomom i sarkomom Ewing u području donjih ekstremiteta, a
tijekom praćenja bolesnika.
Obuhvaćeno je ukupno 83 bolesnika prosječne dobi 13.8 godina (medijan 13
godina) koji su prosječno praćeni 73,8 mjeseci (medijan 58,0 mjeseci). U 36
bolesnika (43,4%) došlo je do širenja bolesti u druge organe (najčešće u pluća,
88,9%), a u 18 bolesnika (21,7%) registriran je lokalni recidiv bolesti.
Ukupno preživljenje tijekom medijana praćenja od 58,0 mjeseci bilo je 61,4%, u
skupini bolesnika sa metastazama preživljenje je bilo 16,7%, a u skupini
bolesnika sa lokalnim recidivom također slabije (27,8%).
U svih bolesnika sa lokalnim recidivom na bolest se posumnjalo učinjenom
trovremenskom scitnigrafijom lokalne regije, a rentgen lokalne regije bio je
pozitivan u samo jednog bolesnika.
Analizirani su doprinosi pojedinih vremena scintigrafije kosti i utvrđeno da nema
povezanosti između prvog vremena snimanja (protok) i pojave lokalnog recidiva
(P= 0,566), dok je potvrđena stastistički značajna povezanost između drugog
vremena snimanja (krvni prostor) i lokalnog recidiva (P<0.001), te kasnih
statičkih scintigrama i lokalnog recidiva (P<0.001).
Patološki nalaz scintigrafije kosti u većine bolesnika bio je uzrokovan benignim
promjenama u lokalnoj regiji (25,3%), a utvrđeno je i 8,4% lažno pozitivnih
nalaza. Analizom osjetljivosti i specifičnosti pojedinih vremena snimanja za
dokazivanje lokalnog recidiva utvrđena je vrlo slaba osjetljivost (38,9%) i loša
specifičnost prvog vremena snimanja (70,8%), a slaba specifičnost drugog
vremena (56,9%) i kasnih statičkih scintigrama (67,7%) uz visoku osjetljivost tih
metoda (94,4% i 89,9%). Isključivanjem bolesnika s pozitivnim nalazom radi
poznatih benignih uzroka dobivena je nešto bolja specifičnost i ranih i kasnih
statičkih scintigrama (84,1% i 86,4%) uz istu osjetljivost.
Obzirom da se radilo o malom uzorku bolesnika analizirani su pojedini
dijagnostički slučajevi i utvrđeno je da je u dvoje bolesnika s negativnim kasnim
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statičkim scintigramima (11,1%) lokalni recidiv u mekim čestima regije bio
detektiran isključivo zahvaljujući ranim statičkim scintigramima.
Rezultati ukazuju da je trovremenska scintigrafija skeleta u praćenju lokalne
regije nedvojbeno korisna metoda, te da se pojedina vremena snimanja
komplementarno nadopunjuju, čime se postiže značajno bolja osjetljivost i
specifičnost postupka. |
| Abstract (english) | The aim of the study was to assess diagnostic usefulness of early phases
of three phase bone scan (angioscintigraphy and blood pool) during follow-up of
local region in patients with osteosarcoma and sarcoma Ewing of lower
extremities.
Eighty-three patients were included, average follow-up period was 73.8
months (median 58.0 months) and average patients age was 13.8 years (median
13.0 years). In 36 patients (43.4%) metastasis spread was noticed and the most
frequent region involved were lungs (88.9%). Local relapse was noticed in 18
patients (21.7%).
Overall survival of all patients during follow-up period was 61.4%, while
in the patients with metastatic disease overall survival was lower (16.7%) and in
patients with local relapse was lower as well (27.8%).
In all patients local relapse was detected by three-phase bone scan of
local region and local x-ray was positive only in one patient. Contribution of
each phase of three phase-bone scan (angioscintigraphy, blood pool and late
images) in assessing local relapse was analyzed and no correlation was
confirmed between angioscintigraphy and local relapse (P=0.566), but
correlation between blood pool (P<0.001) or late images (P<0.001) and local
relapses were confirmed.
Besides malignant changes of local region (local relapses) generally the
most frequent reasons for pathologic changes of bone scans in all patients were
benign changes (25.3%) and 8.4% reports were falsely positive (nor benign
neither malignant changes confirmed during whole follow-up period).
Sensitivity and specificity of each phase to detect local relapse was
analyzed: angioscintigraphy 38.9% and 70.8%; blood pool 94.4% and 56.9%;
late images 89.9% and 67.7%. Excluding patients with known benign reasons for
positive bone scans we could obtain better specificity. Blood pool specificity
increased to 84.1% and for late images specificity increased to 86.4%.
Since we had relatively small group of patients we analyzed each case
separately («case based reasoning») and established that in two patients local
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relapse (which was in soft tissues of the region) was missed by late images and
was confirmed particularly as a result of positive blood pool images (11.1%).
Our results suggest that sensitivity of the late phase of bone scan is not
sufficient to detect early local relapse in soft tissue. Early phases of bone scan
complement to late phase so we would recommend them in the follow-up of
local region in patients with osteosarcoma and sarcoma Ewing to achieve
significantly better sensitivity of the procedure. |
