Whole-body Fluorodeoxyglucose Positron Emission Tomography–Computed Tomography for Suspected or Confirmed Brain Metastasis
RKL Lee, K Wang, AWH Ng, CB Ip, JSY Lam, EHY Yuen, TCY Cheung, YYP Lee, TM Chan
Hong Kong J Radiol 2012;15:80-7
Objective: To determine the role of whole-body fluorodeoxyglucose positron emission tomography–computed tomography (FDG PET-CT) in the diagnosis and work-up of suspected or confirmed brain metastasis and to assess its impact on clinical management and outcomes.
Methods:This was a retrospective study of patients who were suspected or confirmed to have brain metastases and had subsequent whole-body PET-CT at a local centre between 2008 and 2011. The PET-CT results were then compared with the biopsy results which were regarded as the gold standard. The clinical management and survival rate were also evaluated.
Results:In all, 58 consecutive patients with suspected or confirmed brain metastasis who underwent whole-body PET-CT were assessed. Among these, 23 patients suffered from multiple brain lesions and in the remainder it was solitary. Eight (group A) of these 58 patients had a biopsy- or resection-confirmed metastatic brain lesion (primary not proven) prior to the PET-CT scan. While the rest (group B, n = 50) had a clinically suspected brain metastasis without histological confirmation prior to the PET-CT. All patients in group A had a solitary brain lesion. Resection or biopsy of the brain lesion prior to the scan and subsequent histology confirmed its metastatic origin. The site of the extracranial primary malignancy was identified in all these patients by PET-CT. Half of them (4/8) later had biopsies of the PET-CT–suspected extracranial primary malignancies, which were all concordant with the brain biopsy results. In group B, 19 PET-CT scans revealed no suspicious uptake extracranially, so the brain lesions were presumed to be primarily of brain origin (termed group B1). Moreover, all of them were also confirmed by subsequent biopsy. Among the remaining 31 patients (termed group B2), 21 were found to have a suspected extracranial primary malignancy based on PET-CT scans that were confirmed by subsequent biopsy (18 non– small-cell lung carcinoma, 1 colonic carcinoma, 1 breast carcinoma, and 1 thymic carcinoma). For brain lesions of patients in whom the PET-CT scan suggested a metastatic origin (groups A + B2), 70% and 49% received wholebrain radiotherapy and chemotherapy, respectively. On the other hand, patients with primary brain lesions (group B1) underwent resection (74%), radiotherapy (68%), and chemotherapy (53%). The survival of the three groups differed significantly (p<0.001). Group B1 showed the best survival followed by group B2 and then group A.
Conclusion: Whole-body 18F-FDG PET-CT is useful for determining whether a brain lesion is primary or metastatic in nature. It is suggested that group A patients may benefit from PET-CT scan via identification of an extracranial primary malignancy. This helps further planning of the treatment to avoid unnecessary resection or biopsy of the metastatic lesion which may not show additional survival benefit and could even result in complications.
中文摘要
全身氟脫氧葡萄糖正電子發射斷層成像和CT掃描（FDG PET-CT） 在疑似或確診腦轉移瘤病例中的角色
李嘉樂、王琪、伍永鴻、葉梓斌、林淑儀、袁學遠、張智欣、李艷萍、陳達明
目的：探討全身FDG PET-CT在診斷及檢查疑似或確診腦轉移瘤的病人中角色，以及評估這技術對於 臨床處理及結果的影響。
方法：回顧2008至2011年期間在本地的一所PET-CT中心疑似或確診腦轉移瘤並接受FDG PET-CT檢查 的病人。比較他們的PET-CT結果和認為是金標準的活檢結果，並評估病人的臨床處理及存活率。
結果：共58名疑似或確診腦轉移瘤並接受FDG PET-CT檢查的病人被列入研究範圍。其中23例有多發 性腦腫瘤，其餘為獨立性腦腫瘤。把病人分為兩組。A組有8例，他們在進行PET-CT檢查前已從活檢 或切除組織中確診為腦轉移瘤，但未能確定其原發灶位置。B組的50例在進行PET-CT檢查前臨床懷 疑患有腦轉移瘤，但未得到組織學的確認。A組的所有病人均為獨立性腦腫瘤，他們在PET-CT檢查 前已從活檢或切除組織以及其後的組織學確認了腦轉移瘤的原發灶位置。他們的PET-CT檢查顯示顱 外原發灶的位置。A組中有4例後來在PET-CT檢查確認的顱外原發灶的位置進行活檢，結果與腦轉移 瘤的活檢組織吻合。B組中有19例的PET-CT結果未發現有顱外瘤，所以認為其腦腫瘤為原發灶（B1 組），全部其後從活檢確診。B組其餘的31例（B2組）中，21例的PET-CT結果發現疑似顱外原發惡 性瘤，後被活檢確診，它們為18例非小細胞肺癌，另結腸癌、乳腺癌及胸腺癌各1例。所有PET-CT 發現有腦轉移瘤的病人中 （A組+ B2組），70%接受全腦放療，49%接受化療。此外，有原發性腦 腫瘤的病人中 (B1組)，74%接受切除手術、68%接受放療、53%接受化療。三組病人的存活率有明顯 分別：B1組有最佳的存活率，其次為B2組及A組。
結論：全身FDG PET-CT能分辨腦腫瘤的原發性還是轉移性。本研究中A組病人因接受PET-CT檢查而 得知顱外原發灶的位置，從而可以進一步計劃治療方案，避免進行不必要的切除或活檢，因為在這 種轉移瘤情況下無論是切除或活檢均可能導致並發症, 但未必能延長病人的存活期。