Role of FDG-PET in the diagnosis and management of lung cancer

Positron emission tomography (PET) using [(18)F]-2-deoxy-2-fluoro-d-glucose (FDG) has emerged as a valuable diagnostic modality in patients with non-small cell lung cancer (NSCLC). Data in the literature show that the addition of FDG-PET definitely alters clinical management in patients with potentially resectable NSCLC by adequately staging the mediastinum and detecting previously unknown distant metastases. Thus, the number of noncurative thoracotomies and unnecessary mediastinoscopies is reduced. Furthermore, there is increasing evidence that FDG-PET will change radiation treatment planning by defining a biologic treatment volume, incorporating unsuspected additional locoregional disease, and avoiding overtreatment by identifying computerized tomography abnormalities as benign. For follow-up during systemic therapy, early FDG-PET appears to be predictive for the response to therapy. However, before FDG-PET-induced changes in patient management can be incorporated into clinical practice both for radiation treatment planning and chemotherapy, technical issues must be resolved, validation studies should be performed and, most importantly, randomized trials are necessary to evaluate the effect of FDG-PET on patient outcome parameters.     

2-[18F]fluoro-2-deoxyglucose positron-emission tomography in staging, response evaluation, and treatment planning of lymphomas

2-[18F]fluoro-2-deoxyglucose positron-emission tomography (FDG-PET) is used increasingly in the clinical management of lymphomas. With regard to staging, FDG-PET is more sensitive and specific than conventional staging methods in FDG avid lymphomas (ie, Hodgkin lymphoma and most aggressive non-Hodgkin lymphomas). Despite methodological problems, in particular the lack of a valid reference test, FDG-PET is approved and generally used for this purpose. With regard to response evaluation, FDG-PET at the end of treatment seems to aid considerably in differentiating between residual masses with or without residual lymphoma. Hence, new revised response criteria have been proposed, incorporating the result of FDG-PET at the end of treatment. An early interim FDG-PET scan after 1 to 3 cycles of chemotherapy is a very strong predictor of outcome, and trials are now in progress testing treatment modifications on this basis. With regard to treatment planning, in the context of combined-modality therapy, radiotherapy for lymphomas is moving toward more conformal techniques reducing the irradiated volume to include only the macroscopic lymphoma. In this situation, accurate imaging is essential, and FDG-PET coregistered with the planning computed tomography (CT) scan is used increasingly. The availability of PET/CT scanners suited for virtual simulation has aided this process. However, clinical data evaluating this technique are at present sparse.     

Role of FDG-PET in the diagnosis and management of lung cancer

Positron emission tomography (PET) using [¹⁸F]-2-deoxy-2-fluoro-d-glucose (FDG) has emerged as a valuable diagnostic modality in patients with non-small cell lung cancer (NSCLC). Data in the literature show that the addition of FDG-PET definitely alters clinical management in patients with potentially resectable NSCLC by adequately staging the mediastinum and detecting previously unknown distant metastases. Thus, the number of noncurative thoracotomies and unnecessary mediastinoscopies is reduced. Furthermore, there is increasing evidence that FDG-PET will change radiation treatment planning by defining a biologic treatment volume, incorporating unsuspected additional locoregional disease, and avoiding overtreatment by identifying computerized tomography abnormalities as benign. For follow-up during systemic therapy, early FDG-PET appears to be predictive for the response to therapy. However, before FDG-PET-induced changes in patient management can be incorporated into clinical practice both for radiation treatment planning and chemotherapy, technical issues must be resolved, validation studies should be performed and, most importantly, randomized trials are necessary to evaluate the effect of FDG-PET on patient outcome parameters.     

Impact of hybrid fluorodeoxyglucose positron-emission tomography/computed tomography on radiotherapy planning in esophageal and non-small-cell lung cancer

PURPOSE: The aim of this study was to investigate the impact of a hybrid fluorodeoxyglucose positron-emission tomography/computed tomography (FDG-PET/CT) scanner in radiotherapy planning for esophageal and non-small-cell lung cancer (NSCLC). METHODS AND MATERIALS: A total of 30 patients (16 with esophageal cancer, 14 with NSCLC) underwent an FDG-PET/CT for radiotherapy planning purposes. Noncontrast total-body spiral CT scans were obtained first, followed immediately by FDG-PET imaging which was automatically co-registered to the CT scan. A physician not involved in the patients' original treatment planning designed a gross tumor volume (GTV) based first on the CT dataset alone, while blinded to the FDG-PET dataset. Afterward, the physician designed a GTV based on the fused PET/CT dataset. To standardize PET GTV margin definition, background liver PET activity was standardized in all images. The CT-based and PET/CT-based GTVs were then quantitatively compared by way of an index of conformality, which is the ratio of the intersection of the two GTVs to their union. RESULTS: The mean index of conformality was 0.44 (range, 0.00-0.70) for patients with NSCLC and 0.46 (range, 0.13-0.80) for patients with esophageal cancer. In 10 of the 16 (62.5%) esophageal cancer patients, and in 12 of the 14 (85.7%) NSCLC patients, the addition of the FDG-PET data led to the definition of a smaller GTV. CONCLUSION: The incorporation of a hybrid FDG-PET/CT scanner had an impact on the radiotherapy planning of esophageal cancer and NSCLC. In future studies, we recommend adoption of a conformality index for a more comprehensive comparison of newer treatment planning imaging modalities to conventional options.     

Intérêt de la tomographie par émission de positons au [18F]-fluoro-2-désoxyglucose dans la détermination des volumes cibles de radiothérapie. Application à l''irradiation conformationnelle des cancers bronchiques non à petites cellules

Traditional radiation treatment planning relies on density imaging such as Computed Tomography for anatomic information of various structures of interest including target and normal tissues. However, the difficulties to distinguish malignant from normal tissue on CT slides often leads to inaccurate outlining of the GTV and/or to geographic misses. 18F-fluorodeoxyglucose positron emission tomography (FDG-PET) has shown an increase in both sensitivity and specificity over CT in locoregional staging of patients with non-small cell lung cancer (NSCLC). The co registration of FDG-PET images to the data of the CT planning offers the radiation oncologist the possibility to include functional information into the target outlining. For the treatment of patients with NSCLC, it has been shown that the use of FDG-PET images: 1) modified the shape and volume of radiation fields in 22-62% of cases, mainly due to a better nodal staging and distinction of atelectasis from tumor and; 2) significatively reduced the interobserver and intraobserver variability. This paper reviews the results reported in the literature. Challenges and proposed solutions are discussed.     

Early Response to Chemotherapy in Patients With Non–Small-Cell Lung Cancer Assessed by [18F]-Fluoro-Deoxy-D-Glucose Positron Emission Tomography and Computed Tomography

BackgroundThis study aimed to demonstrate that patients who exhibit a tumor metabolic response to first-line chemotherapy seen on FDG-PET and computed tomography (CT) would survive longer than those who did not show such a response, comparing this evaluation with the morphologic response seen on CT.Patients and MethodsImages were acquired in 22 consecutive patients with advanced non–small-cell lung cancer (NSCLC) randomized to receive carboplatin/paclitaxel/sorafenib or placebo. FDG-PET was performed within 4 weeks before (PET1) and 2 weeks after starting treatment (PET2). Similarly, CT (CT1) was performed at baseline and then every 2 cycles (6 weeks) during treatment (CT2). Responders and nonresponders were identified with FDG-PET, and metabolic response was then compared with morphologic changes detected by spiral CT.ResultsTwenty-one of 22 patients completed this study. In terms of progression-free survival (PFS) (45 vs. 22.2 weeks) and overall survival (OS) (77 vs. 47.7 weeks), we observed a trend that was not statistically significant for patients whose response after 2 weeks of treatment was seen on FDG-PET (P = .22 for PFS; P = .15 for OS).ConclusionPatients with advanced NSCLC who had a positive outcome, as evidenced by prolonged survival, were those who showed a tumor metabolic response seen on FDG-PET.     

Posttreatment assessment of response using FDG-PET/CT for patients treated with definitive radiation therapy for head and neck cancers

PURPOSE: The goal of this study was to evaluate coregistered [18F] fluorodeoxyglucose (FDG)-positron emission tomography (PET)/computed tomography (CT) for the detection of persistent disease after definitive radiation therapy in head and neck cancer. METHODS AND MATERIALS: Posttreatment FDG-PET/CT was performed in 28 patients on average 8 weeks (range, 4 to 15.7 weeks) after completing definitive radiation therapy. FDG-PET/CT was visually analyzed for the entire patient group and at two time points (4-8 and >8 weeks) after treatment. The contrast-enhanced CT portion of PET/CT was separately analyzed blinded to the results of coregistered FDG-PET/CT and classified as negative or positive for residual locoregional disease. Pathologic findings and clinical follow-up served as the reference standard. RESULTS: Follow-up data were available for all 28 patients (median, 17.6 months). Regarding the detection of residual disease, the overall sensitivity and specificity of FDG-PET/CT was 76.9% and 93.3%, respectively, compared with 92.3% and 46.7% for contrast-enhanced CT. The accuracy of FDG-PET/CT was 85.7%, compared with 67.9% for CT alone. All false-negative (n = 3) and false-positive (n = 1) FDG-PET/CT results occurred between 4 and 8 weeks after treatment. At 8 weeks or later after treatment, the specificity of CT was 28%, compared with 100% for FDG-PET/CT. CONCLUSIONS: The metabolic-anatomic information from coregistered FDG-PET/CT provided the most accurate assessment for treatment response when performed later than 8 weeks after the conclusion of radiation therapy. FDG-PET/CT excelled by a higher specificity and overall diagnostic performance than CT imaging alone. These results support a potential clinical role of FDG-PET/CT in the early assessment of therapy response after definitive radiation therapy.     

18F-fluoro-2-deoxy-D-glucose positron emission tomographic imaging: recent developments in head and neck cancer

PURPOSE OF REVIEW: Positron emission tomography using 18F-fluoro-2-deoxy-D-glucose (18FDG-PET) is well established in clinical routine as a metabolism-based whole-body imaging tool for cancer diagnosis and follow-up. Several reports have appeared indicating the potential and limitations of this technique in head and neck cancer (HNC). This review limits its scope to the recent advances using 18FDG-PET in the clinical management of HNC. RECENT FINDINGS: The combination of 18FDG-PET and sentinel node biopsy has been explored for the surgical treatment planning of oral and oropharyngeal cancer. Recent reports indicate that multimodality imaging combining PET with high-end CT scanning increases the diagnostic accuracy. 18FDG-PET has a potential for use in radiation treatment planning and for the prediction of response and early evaluation of treatment efficacy. SUMMARY: Increasingly 18FDG-PET is used as a clinical imaging modality in the different stages of the management of HNC. In particular, its clinical value in initial staging of neck lymph nodes and in the evaluation of recurrent or residual disease is well established. In these settings 18FDG-PET has been shown to be more accurate than conventional imaging. Recent studies indicate that 18FDG-PET could be of additional value in staging the N0 neck, in radiation treatment planning, and in prediction of treatment efficacy.     

Value of positron emission tomography for lung cancer staging.

OBJECTIVE: The therapeutic strategy in non-small-cell lung cancer (NSCLC) requires exact staging of tumour invasion (T) as well as differentiation between ipsi- and contralateral lymph node invasion (N1/2 vs N3). [18F]FDG-positron emission tomography (FDG-PET) has been shown to detect invaded N with high accuracy while correct determination of T appears to be unclear. The purpose of this prospective study was to evaluate benefit and necessity of 18FDG-PET as an additive to conventional staging modalities. METHODS: Forty patients with suspected non-small-cell lung cancer (NSCLC) were staged by means of computed tomography (CT), bronchoscopy, mediastinoscopy and bone scintigraphy. Additionally, attenuation corrected FDG-PET of the thorax was performed pre-operatively for analysis of T and N topography. After surgical resection with radical lymphadenectomy T and N staging results of CT and PET were compared with the pathological diagnoses. Specificity, sensitivity, positive predictive value and accuracy of CT and PET were calculated. RESULTS: Twenty three squamous cell carcinomas, 14 adenocarcinomas, and three non-malignant tumours were found. Accuracy of CT-T was 0.75 and of PET-T 0.78; accuracy of CT-N was 0.78 and of PET-N 0.80. By combination of CT-T and PET-T accuracy was 0.88. Combination of CT-N and PET-N yielded an accuracy of 0.90. In two out of three cases, PET correctly determined T0. In two cases non-malignant inflammatory lymph nodes were falsely staged as malignant by PET. CONCLUSIONS: Adequate pre-operative T- and N-staging is possible with both CT and FDG-PET. Accuracy can be improved by combination of CT and FDG-PET. FDG-PET is superior to CT in order to differentiate between malignant and benign tumours. However, acute inflammation can mimic malignant lymph node invasion. FDG-PET is justified as a supporting staging measure in cases presenting unclear differentiation between N2 and N3 after conventional staging and is helpful in cases with unclear cell type of the primary tumour.     

PET／CT在非小细胞肺癌疗效预测评价中的研究进展

18F-脱氧葡萄糖（18F-FDG）正电子发射断层显像计算机断层成像（PET／CT）已广泛用于非小细胞肺癌（NSCLC）的诊疗,特别对NSCLC疗效预测具有重要价值。PET／CT可以动态观察肿瘤组织的代谢,根据治疗前后肿瘤组织对18F-FDG的摄取变化,通过可视或定量分析,在临床或亚临床水平达到早期预测NSCLC治疗疗效的目的。现将PET/CT应用于评价NSCLC疗效的文献作一综述。     

18F-FDG PET/CT for assessing heterogeneous metabolic response between primary tumor and metastases and prognosis in non-small cell lung cancer

IntroductionThis study aimed to use ¹⁸F-fluorodeoxyglucose positron emission tomography and/or computed tomography (¹⁸FDG-PET/CT) imaging to evaluate the heterogeneous metabolic response between primary tumor and metastases in NSCLC after therapy and explored its correlation with prognosis.MethodsThe data of patients with NSCLC who underwent ¹⁸FDG-PET/CT before and after treatment were retrospectively analyzed. Heterogeneous metabolic response (HR), defined as the difference in metabolic response between any metastases and primary lesion, was evaluated using ¹⁸FDG-PET/CT. And the correlation between HR and clinical prognosis was also analyzed.ResultsA total of 56 patients with NSCLC including 56 primary lesions and 491 metastases were enrolled in the study. 46.4% (26/56) of patients had HR, especially in patients with stage IV disease and whose metastases with high metabolic burden. HR was significantly correlated with poorer overall survival (OS) and progression-free survival (PFS) (P < .001 and P = .045, respectively). The multivariate analysis suggested that HR was an unfavorable independent prognostic factor for OS (HR = 4.36; 95% CI, 2.00–9.49; P < .001) but not for PFS (P = .469). HR between lymph node metastases was correlated with shorter OS (P < .001) but not with PFS (P = .370).ConclusionHR was observed between primary and metastatic lesions in NSCLC after treatment using PET/CT. HR is significantly associated with poor prognosis and is an independent prognostic factor for OS.     

FDG-PET/CT in the evaluation of anal carcinoma

PURPOSE: Surgical staging and treatment of anal carcinoma has been replaced by noninvasive staging studies and combined modality therapy. In this study, we compare computed tomography (CT) and physical examination to [(18)F]-fluoro-2-deoxy-D-glucose-positron emission tomography/computed tomography (FDG-PET/CT) in the staging of carcinoma of the anal canal, with special emphasis on determination of spread to inguinal lymph nodes. METHODS AND MATERIALS: Between July 2003 and July 2005, 41 consecutive patients with biopsy-proved anal carcinoma underwent a complete staging evaluation including physical examination, CT, and 2-FDG-PET/CT. Patients ranged in age from 30 to 89 years. Nine men were HIV-positive. Treatment was with standard Nigro regimen. RESULTS: [(18)F]-fluoro-2-deoxy-D-glucose-positron emission tomography/computed tomography (FDG-PET/CT) detected 91% of nonexcised primary tumors, whereas CT visualized 59%. FDG-PET/CT detected abnormal uptake in pelvic nodes of 5 patients with normal pelvic CT scans. FDG-PET/CT detected abnormal nodes in 20% of groins that were normal by CT, and in 23% without abnormality on physical examination. Furthermore, 17% of groins negative by both CT and physical examination showed abnormal uptake on FDG-PET/CT. HIV-positive patients had an increased frequency of PET-positive lymph nodes. CONCLUSION: [(18)F]-fluoro-2-deoxy-D-glucose-positron emission tomography/computed tomography detects the primary tumor more often than CT. FDG-PET/CT detects substantially more abnormal inguinal lymph nodes than are identified by standard clinical staging with CT and physical examination.     

Frequent impact of [18F]fluorodeoxyglucose positron emission tomography on the staging and management of patients with indolent non-Hodgkin's lymphoma

[18F]fluorodeoxyglucose (FDG) positron emission tomography (PET) is useful in staging aggressive non-Hodgkin's lymphoma (NHL). However, its role in indolent NHL has not been established. This retrospective study assessed the sensitivity and clinical impact of PET findings in patients with indolent NHL. Patients with indolent NHL who underwent FDG-PET scanning between May 1997 and August 2001 were identified. Case records were reviewed for FDG-PET and conventional staging/restaging results and compared for concordance. Forty-seven patients were identified. Twelve staging FDG-PET scans and 37 restaging FDG-PET scans were obtained. The FDG-PET case sensitivity rate was 98%. Forty-two percent of staging FDG-PET scans were concordant with conventional staging, with the remaining patients exhibiting more extensive disease on PET. At progression, FDG-PET and conventional assessments were discordant in 46% of cases. Positron emission tomography findings downstaged disease in 30% of these patients and upstaged disease in 16%. Computed tomography (CT) and FDG-PET identified 150 and 146 individual sites of disease, respectively. Among "definite" sites on structural imaging, 74% were also seen on PET. For equivocal lesions, only 19% were seen on both modalities. Clinical management was changed in 34% of patients as a result of FDG-PET findings. Of 22 discordant lesions in which true disease status could be evaluated, the PET findings were confirmed to be correct in 21 (95%; P < 0.0001). These findings demonstrate that FDG-PET has a high sensitivity for indolent NHL and often leads to alteration of disease staging and management. This high accuracy of FDG-PET in assessing discordant lesions suggests a greater diagnostic utility compared with CT.     

Whole body positron emission tomography with 18F-fluoro-2-deoxyglucose for the detection of recurrent ovarian cancer

Although many cancers can be detected by whole-body positron emission tomography (PET) with 18F-fluoro-2-deoxyglucose (FDG), there has been limited clinical experience with FDG-PET for the detection of recurrent ovarian cancers. Therefore, the aim of this study was to evaluate the clinical value of FDG-PET in the detection of recurrent ovarian cancer. Whole body FDG-PET scans were performed on 24 women who had previous histories of ovarian cancer and treatment with surgery and chemotherapy. All patients also underwent physical examination, laboratory testing of serum CA-125 level and pelvic-abdominal-chest computed tomography (CT) or magnetic resonance imaging (MRI). The results of FDG-PET scans were correlated with serum CA-125 level, CT/MRI and operative pathology results. The diagnostic sensitivity was 90.9%, 90.9% and 90.9%, specificity was 92.3%, 76.9% and 46.2% and accuracy was 91.7%, 83.3% and 66.7% for FDG-PET, serum tumor marker of CA-125 level and CT/MRI in detecting recurrent ovarian cancer, respectively. FDG-PET is a useful diagnostic tool in detecting recurrent ovarian cancers with high specificity as compared with the serum tumor marker CA-125 level and the conventional CT/MRI morphological imaging methods.     

Impact of FDG-PET on radiation therapy volume delineation in non-small-cell lung cancer

PURPOSE: Locoregional failure remains a significant problem for patients receiving definitive radiation therapy alone or combined with chemotherapy for non-small-cell lung cancer (NSCLC). Positron emission tomography (PET) with [(18)F]fluoro-2-deoxy-d-glucose (FDG) has proven to be a valuable diagnostic and staging tool for NSCLC. This prospective study was performed to determine the impact of treatment simulation with FDG-PET and CT on radiation therapy target volume definition and toxicity profiles by comparison to simulation with computed tomography (CT) scanning alone. METHODS: Twenty-six patients with Stages I-III NSCLC were studied. Each patient underwent sequential CT and FDG-PET simulation on the same day. Immobilization devices used for both simulations included an alpha cradle, a flat tabletop, 6 external fiducial markers, and a laser positioning system. A radiation therapist participated in both simulations to reproduce the treatment setup. Both the CT and fused PET/CT image data sets were transferred to the radiation treatment planning workstation for contouring. Each FDG-PET study was reviewed with the interpreting nuclear radiologist before tumor volumes were contoured. The fused PET/CT images were used to develop the three-dimensional conformal radiation therapy (3DCRT) plan. A second physician, blinded to the results of PET, contoured the gross tumor volumes (GTV) and planning target volumes (PTV) from the CT data sets, and these volumes were used to generate mock 3DCRT plans. The PTV was defined by a 10-mm margin around the GTV. The two 3DCRT plans for each patient were compared with respect to the GTV, PTV, mean lung dose, volume of normal lung receiving > or =20 Gy (V20), and mean esophageal dose. RESULTS: The FDG-PET findings altered the AJCC TNM stage in 8 of 26 (31%) patients; 2 patients were diagnosed with metastatic disease based on FDG-PET and received palliative radiation therapy. Of the 24 patients who were planned with 3DCRT, PET clearly altered the radiation therapy volume in 14 (58%), as follows. PET helped to distinguish tumor from atelectasis in all 3 patients with atelectasis. Unsuspected nodal disease was detected by PET in 10 patients, and 1 patient had a separate tumor focus detected within the same lobe of the lung. Increases in the target volumes led to increases in the mean lung dose, V20, and mean esophageal dose. Decreases in the target volumes in the patients with atelectasis led to decreases in these normal-tissue toxicity parameters. CONCLUSIONS: Radiation targeting with fused FDG-PET and CT images resulted in alterations in radiation therapy planning in over 50% of patients by comparison with CT targeting. The increasing availability of integrated PET/CT units will facilitate the use of this technology for radiation treatment planning. A confirmatory multicenter, cooperative group trial is planned within the Radiation Therapy Oncology Group.     

18FDG-PET/CT对评价TACE联合RFA治疗原发性肝癌的效果的价值

背景与目的:原发性肝癌经动脉导管栓塞化疗(transcatheterarterialchemo-embolization,TACE)联合射频消融(radiofrequencyablation,RFA)治疗后,CT扫描对判断是否有肿瘤残留存在一定的困难,而18FDG-PET/CT(18-fluorodeoxyglucose-positronemissiontomograply/CT)在判断肿瘤残留上具有优势。本研究对13例原发性肝癌经TACE联合RFA治疗周后,采用CT和18FDG-PET/CT检查是否存在肿瘤残留,分析CT和18FDG-PET/CT在判断肿瘤残留上的差异,并根据18FDG-PET/CT的结果指导肿瘤治疗。方法:本组13例原发性肝癌患者共有18个病变,肿瘤最长直径为0.8～16.0cm。12例为初治病例;1例为肝癌手术后复发,肝内共发现有3个病变。经过TACE联合RFA治疗后2～3周,对比CT和18FDG-PET/CT检查的结果;如发现有肿瘤残留,在2～3周内对其进一步行RFA治疗。结果:13例患者经一次TACE联合一次RFA治疗2～3周,经病变区域活检及数字减影血管造影等检查发现11例有部分肿瘤残留,肿瘤残留最长直径为1.0～2.1cm;CT增强扫描检查检出5例,18FDG-PET/CT检出有10例残留,CT与18FDG-PET/CT检出率分别为45.4%及90.9%。根据检查结果,在2～3周内经过第二次RFA治疗后,18FDG-PET/CT检查发现10例患者肿瘤无残留,另1例6周后复查18FDG-PET/CT发现肝内病变未控,患者带瘤生存。结论:原发性肝癌经TACE联合RFA治疗以及手术后,18FDG-PET/CT对判断肿瘤残留以及根据检查结果指导RFA治疗较CT检查具有更大的优势。     

Diagnostic imaging--recent progress

Current advances in the diagnostic imaging for lung cancer includes multidetector-row CT (MDCT), lung cancer screening using low-dose MDCT and fluorodeoxyglucose positron emission tomography (FDG-PET) imaging. There is no question about the clinical usefulness of MDCT, and the further development of the hardware and the software of MDCT will open new horizons for CT diagnosis. PET is not an alternative modality to CT but a supplementary one, which adds metabolic information to the morphology. Recently, experimental research on the refraction imaging of human lung specimens has been performed with synchrotron radiation. With progressive refinement, this technique may come to have some practical purpose in diagnosing lung cancer in vivo.     

Follow-up with 18FDG-PET–CT after radical radiotherapy with or without chemotherapy allows the detection of potentially curable progressive disease in non-small cell lung cancer patients: A prospective study

BackgroundFollow-up of patients treated with curative intent for non-small cell lung cancer (NSCLC) with X-ray or CT-scans is of unproven value. Furthermore, most patients with progressive disease present with symptoms outside of follow-up visits. Because the accuracy of ¹⁸FDG-PET–CT is superior to CT, we hypothesised that FDG-PET–CT scans 3 months post-treatment could lead to early detection of progressive disease (PD) amenable for radical treatment.Patients and methodsHundred patients with NSCLC, treated with curative intent with (chemo) radiation, were prospectively evaluated. All patients underwent a planned FDG-PET–CT scan 3 months after the start of radiotherapy.ResultsTwenty four patients had PD 3 months post-treatment. 16/24 patients were symptomatic. No curative treatment could be offered to any of these patients. In 3/8 asymptomatic patients progression, potentially amenable for radical therapy was found, which were all detected with PET, not with CT only.ConclusionsPET-scanning after curative treatment for NSCLC led to the detection of progression potentially amenable for radical treatment in a small proportion (3%) of patients. Selectively offering a PET–CT scan to the patient group without symptoms could possibly lead to an effective follow-up method.     

PET/CT supports breast cancer diagnosis and treatment

The application of positron emission tomography with ¹⁸F fluoro-2-deoxy-d-glucose (FDG-PET) has remarkably improved the management of cancer patients. However, some caution is necessary in the interpretation of FDG-PET images. Because of its low spatial resolution, it is difficult to identify the anatomical location of radiotracer uptake and to distinguish between normal physiological accumulation and pathological uptake. A novel combined PET/CT system has been developed that improves the capacity to correctly localize and interpret FDG uptake. Although only a few studies have been conducted on the potential role of PET/CT in the management of breast cancer patients, the advantage of this modality compared with PET alone should be relevant for application in the field of breast cancer. In this review, we describe the clinical impact of PET/CT on breast cancer diagnosis compared with PET alone with respect to disease restaging, treatment monitoring, preoperative staging and primary diagnosis. In addition, the possible role of PET/CT with iodine contrast is noted for evaluation of intra-ductal spreading.     

FDG-PET and stereotactic body radiotherapy (SBRT) for stage I non-small-cell lung cancer

PURPOSE: To investigate the utility of positron emission tomography (PET) in patients treated with stereotactic body radiotherapy (SBRT) for stage I non-small-cell lung cancer (NSCLC) on prospective institutional trials. PATIENTS AND METHODS: Fifty-eight patients with medically inoperable stage I NSCLC who participated in prospective phase I and II trials of SBRT, had >or=2 years of follow-up, and received FDG-PET imaging are the focus of this evaluation. Fifty-seven of 58 patients received pre-SBRT FDG-PET to confirm stage I status. All patients received stereotactic body frame immobilization and treatment with 7-10 photon beams. SBRT total doses ranged from 24 to 72Gy in three fractions. No elective nodal irradiation was undertaken. Regular follow-up with planned CT imaging was performed on all patients. Post-SBRT FDG-PET was not mandated by protocol and was typically ordered upon concern for disease recurrence. Thirty-eight post-SBRT PET studies were performed in 28 patients at a median 17.3 months following SBRT. RESULTS: With a median follow-up of 42.5 months, the 3-year actuarial overall survival and local control for this select subset of our SBRT experience were 48.9% and 74.8%, respectively. Pre-SBRT FDG-PET SUV did not predict 3-year overall survival or local control. Fourteen of 57 patients eventually failed in nodal stations by CT and/or PET. Isolated first site of failure was nodal in 6 patients (10%). Out of 28 patients with post-SBRT PET, 4 (14%) had delayed PET imaging (22-26 months after SBRT) showing moderate hypermetabolic activity (SUV 2.5-5.07), but no evidence of local, nodal, or distant recurrence by clinical examination and conventional imaging performed 20-26 months following these concerning PET findings. CONCLUSIONS: Isolated nodal recurrence following PET-staged I NSCLC treated with SBRT is uncommon. Moderate post-SBRT PET hypermetabolic activity may persist 2 years following treatment without definite evidence of recurrence. Further study is needed to confirm these results in larger populations with longer follow-up.