Differentiation of tumor recurrence from radiation-induced pulmonary fibrosis after stereotactic ablative radiotherapy for lung cancer: characterization of 18F-FDG PET/CT findings

Objective

Stereotactic ablative radiotherapy (SABR), also known as stereotactic body radiotherapy (SBRT), is now a standard treatment option for patients with stage I non-small cell lung cancer or oligometastatic lung tumor who are medically inoperable or medically operable but refuse surgery. When mass-like consolidation is observed on follow-up CT after SABR, it is sometimes difficult to differentiate tumor recurrence from SABR-induced pulmonary fibrosis. In this study, we evaluated the role of ¹⁸F-fluorodeoxyglucose positron emission tomography combined with computed tomography (FDG-PET/CT) in differentiating tumor recurrence from radiation fibrosis after SABR.

Methods

Between June 2006 and June 2009, 130 patients received SABR for stage I non-small cell lung cancer or metastatic lung cancer at our institution. Fifty-nine patients of them were imaged with FDG-PET/CT after SABR. There were a total of 137 FDG-PET/CT scans for retrospective analysis. The FDG uptake in the pulmonary region was assessed qualitatively using a 3-point scale (0, none or faint; 1, mild; or 2, moderate to intense), and the shape (mass-like or non mass-like) was evaluated. For semi-quantitative analysis, the maximum standardized uptake value (SUV_max) was calculated.

Results

Sixteen of 59 patients had local failure. In recurrent tumor, the combination of intensity grade 2 and mass-like shape was most common (21/23; 91 %). By contrast, in cases of radiation fibrosis, the combination of intensity grade 0 or 1 and non mass-like shape was most common (48/59; 81 %). The SUV_max of tumor recurrence after 12 months was significantly higher than that of radiation fibrosis (8.0 ± 3.2 vs. 2.1 ± 0.9, p < 0.001), and all tumor recurrence showed the SUV_max > 4.5 at diagnosis of local failure. At ≥12 months after SABR, these two variables, the combination of intensity 2 and mass-like FDG uptake or SUV_max > 4.5 acquired a significant high predictive value of local recurrence, finding sensitivity 100 % and specificity 100 % for both of them.

Conclusions

The combination of FDG uptake patterns and SUV_max was useful for distinguishing tumor recurrence from radiation fibrosis after SABR.     

Role of 2-[18F]fluoro-2-deoxyglucose positron emission tomography in preoperative management of solid-type small-sized lung cancer

Objective

2-[18F]Fluoro-2-deoxyglucose positron emission tomography (FDG-PET) is routinely used for the diagnosis of primary lung cancer. However, the role of FDG-PET in the diagnosis and staging of small-sized lung cancer has not been sufficiently evaluated. The purpose of this study was to determine the utility of FDG-PET for preoperative staging of solid-type small-sized lung cancer manifesting as solid-component predominant nodules.

Methods

One-hundred and eighteen patients with solid-type small-sized (≤2 cm) lung cancer diagnosed as clinical stage IA based on thin-slice computed tomography (TS-CT) were included in this study. Before surgery, FDG-PET was performed in 78 patients (CT/PET group), and TS-CT alone was performed in 40 patients (CT group). Clinical and pathological stage and prognosis were retrospectively reviewed according to whether FDG-PET had been performed.

Results

No significant differences in clinical factors were observed when comparing the CT/PET group and the CT group. Of the 78 patients in the CT/PET group, 12 (15.4 %) were diagnosed with clinical stage IIA or IIIA disease based on FDG-PET findings, but no advanced cases with contraindications for curative surgery were seen. In the CT/PET group, the pathological stage was IA in 66 patients, IB in eight patients, IIA in one patient, and IIIA in three patients; 16 patients had incorrectly staged disease. The accurate staging rate was 79.5 % for the CT–PET group and 70.0 % for the CT group (P = 0.262). Among patients diagnosed with clinical stage IA disease, the 3-year overall survival rate was 85.5 % for the 66 patients in the CT/PET group and 76.8 % for the 40 patients in the CT group (P = 0.554). No significant difference was observed in accuracy of preoperative staging and prognosis between the two groups.

Conclusions

FDG-PET produced no clear benefit for the preoperative management of patients with solid-type clinical T1aN0M0 lung cancer, in terms of postoperative survival and the concordance rate of clinical and pathological stage.     

Percutaneous radiofrequency ablation for patients with malignant lung tumors: a phase II prospective multicenter study (JIVROSG-0702)

Purpose

This prospective multicenter study aimed to evaluate the efficacy and safety of percutaneous radiofrequency (RF) ablation for lung cancer.

Materials and methods

From May 2008 to April 2012, 33 patients (26 men, 7 women; mean age 70.5 years) were enrolled. RF ablation was performed using an internally cooled or expandable multitined electrode. The primary endpoint was complete response (CR) determined using ¹⁸F fluorodeoxyglucose positron emission tomography/computed tomography (FDG-PET/CT) performed 6 months after RF ablation. The secondary endpoint was the incidence and grade of adverse events (AEs) evaluated using the Common Toxicity Criteria for Adverse Events, version 3.0.

Results

All patients underwent RF ablation and had efficacy analyses evaluated; however, FDG-PET/CT images before RF ablation were not available for two patients. The CR rate was 68 % (21 of 31 patients). One patient had a grade 5 AE unrelated to RF ablation. Grade ≥3 AEs occurred in 12 % of patients. During the follow-up period (median 37 months; range 1–55 months), five patients developed local tumor progression and nine (29 %) died. Overall survival at 1, 2, and 3 years was 97, 82, and 74 %, respectively.

Conclusion

Percutaneous RF ablation is a safe, feasible, and effective treatment for small malignant lung tumors.

     

Imaging for lung cancer restaging

Diagnostic imaging plays an important role in the monitoring of tumor response during lung cancer restaging to evaluate the efficacy of chemotherapy and/or radiation therapy during treatment, and in the detection of recurrent or metastatic neoplasm after treatment has been completed. While CT represents the primary imaging modality for lesion evaluation during restaging and for surveillance imaging once therapy has been completed, studies evaluating the role of 18-fluoro-2 deoxyglucose positron emission tomography (FDG-PET) in lung cancer restaging have shown promise regarding the detection of residual and recurrent neoplasm, and in evaluating for early response to first line therapy. With both CT and FDG-PET, residual or recurrent disease should, when possible, be differentiated from therapy-related changes in the lungs. We review the role of imaging in lung cancer restaging with attention to CT and FDG-PET for treatment assessment and the detection of recurrent or metastatic disease.     

PET versus PET/CT dual-modality imaging in evaluation of lung cancer

Non-small cell lung cancer (NSCLC) accounts for approximately 80% of bronchogenic malignancies. The choice of therapy options, including surgery, radiation therapy, and chemotherapy-used alone or in combination-is based on the tumor stage. Consequently, the accurate determination of tumor size, potential infiltration of adjacent structures, mediastinal lymph node involvement, and the detection of distant metastases are of central importance. The purpose of this article is to summarize the accuracy of dual-modality FDG-PET/CT imaging in staging of NSCLC as compared with FDG-PET alone, and with FDG-PET as well as CT read side by side. Furthermore, an optimized PET/CT protocol for patients who have lung cancer is outlined.     

Characterizing bone marrow involvement in Hodgkin’s lymphoma by FDG-PET/CT

Purpose

Fluoro-deoxyglucose positron emmission tomography combined with computed tomography (FDG-PET/CT) is superior to iliac bone marrow biopsy (iBMB) for detection of bone marrow involvement (BMI) in staging of Hodgkin’s lymphoma (HL). The present study aims to characterize the patterns and distribution of BMI in HL as determined by FDG-PET/CT.

Methods

Reports of FDG-PET/CT studies performed for staging of HL were reviewed. BMI was defined as positive iBMB and/or foci of pathological FDG uptake in the skeleton that behaved in concordance with other sites of lymphoma in studies following chemotherapy. Number of FDG uptake foci, their specific location in the skeleton and the presence of corresponding lesions in the CT component of the study, and stage according to the Ann Arbor staging system, were recorded.

Results

The study included 473 patients. iBMB was performed in 336 patients. Nine patients had positive iBMB (9/336, 3 %). Seventy-three patients (73/473, 15 %) had FDG-PET/CT-defined BMI. The BM was the only extranodal site of HL in 52/473 patients (11 %). Forty-five patients had three or more foci of pathological skeletal FDG uptake (45/73, 62 %). Sixty-four patients (64/73, 88 %) had at least one uptake focus in the pelvis or vertebrae. In 60 patients (60/73, 82 %), the number of skeletal FDG uptake foci without corresponding CT lesions was equal to or higher than the number of foci with morphological abnormalities.

Conclusion

FDG-PET/CT demonstrated BMI in 15 % of patients with newly diagnosed HL. Diagnosis of BMI in HL by FDG-PET/CT was more sensitive than iBMB with potential upstage in 11 % of patients. The most common pattern of FDG-PET/CT BMI was multifocal (at least three foci) skeletal FDG uptake, with at least one focus in the pelvis or vertebrae and no corresponding CT lesions.     

Prognostic factors in stereotactic body radiotherapy of lung metastases

Purpose

The aim of this study was to evaluate prognostic factors in patients with lung metastases who undergo lung stereotactic body radiotherapy (SBRT).

Materials and methods

A total of 87 patients with 129 lung metastases who underwent SBRT between November 2004 and May 2012 were enrolled in this retrospective study. The patient collective consisted of 54 men (62.1%) and 33 women (37.9%); the median age was 65 years (range 36–88). The Karnofsky performance index was ≥70% (median 90%) for all cases, but one (60%). Adverse effects were categorized using the CTCAE 4.0 classification system. Retrospective analyses regarding patients’ characteristics, progression-free survival (PFS), overall survival (OS), disease-specific survival (DSS), and local tumor control rates (LTC) were performed.

Results

On univariate and multivariate analysis OS, DSS, and PFS were significantly (p?<?0.05) better for patients with ≤3 lung metastases; no extrathoracic metastases at the time of the SBRT; a gross tumor volume (GTV) <7.7?cm³ and patients that received a staging that included positron emission tomography with fluorine 18 fluorodeoxyglucose/computed tomography (FDG-PET/CT) imaging. Furthermore, a longer OS was observed if newly diagnosed metastases during follow-up were limited to the lung (median survival: 43.7 months versus 21.7 months; p?=?0.023).

Conclusion

The number and pattern of metastases, and the size of the target volume are strong predictors for the outcome of patients receiving SBRT of lung tumors. FDG-PET/CT should be part of pretherapeutic staging before SBRT.

     

FDG-PET and CT in Evaluation of Chemotherapy in Advanced Head and Neck Cancer

Purpose: To compare [18F]2-deoxy-2-fluoro-D-glucose-positron emission tomography (FDG-PET) and computed tomography (CT) scans in assessment of response to neoadjuvant chemotherapy in advanced head and neck cancer.Materials and Methods: In a prospective clinical study, advanced head and neck cancer patients were enrolled in a neoadjuvant organ preservation protocol and received CT and FDG-PET scans prior to and after 2 or 3 rounds of chemotherapy. All patients had prechemotherapy and postchemotherapy tissue biopsies within the tumor region. Patients were then classified as pathologic complete response (PCR) or residual disease (RD) based on biopsies. Analysis of the tumor activity, using FDG-PET, was performed using standardized uptake ratios (SUR) in the region of the primary tumor. Analysis of the tumor size, using contrast enhanced CT, was performed using measurements of the primary tumor in 3 dimensions.Results: Nineteen of the 28 patients with stage III and IV cancer of the head and neck enrolled between December 1994 and May 1996 completed the study. Three patients were PCR and had a mean SUR reduction of 82% by positron emission tomography (PET) and volume reduction of 80% by CT. Sixteen patients had RD after chemotherapy, their SUR and volume reductions were 32% and 41%, respectively. Reduction in SUR with PET was significant. The mean tumor volume reduction by CT approached statistical significance. There was a positive correlation between the percent reduction in tumor volume and SUR (P < 0.004).Conclusion: FDG-PET and CT imaging are at least equivalent in correctly assessing tumor response to chemotherapy with a trend toward better performance by PET.     

Widespread metastases from sarcomatoid renal cell carcinoma detected by 18F-FDG positron emission tomography/computed tomography

We present a case of sarcomatoid renal cell carcinoma (RCC). Although preoperative computed tomography (CT) scans demonstrated small lung and pleural nodules and mediastinal lymphadenopathy, these findings were not conclusive for metastases. Whole-body fluorine-18 fluorodeoxyglucose positron emission tomography and CT (FDG-PET/CT) performed 15 days after right nephrectomy showed intense FDG uptake in the aforementioned lesions (lung and pleural nodules, mediastinal lymph nodes). Unexpectedly, focal increased FDG uptake was found in the right infraspinatus muscle. FDG-PET/CT was considered useful for evaluating distant metastases and thus portending the aggressive nature of sarcomatoid RCC.     

F-FDG18PET/CT incidental detection of tumor-to-tumor metastasis in patients investigated for squamous cell lung cancer

Tumor-to-tumor metastasis (TTM) is a well-known entity, although this is still an extremely rare phenomenon. The lung cancers are considered the most frequent metastatic donors while kidney cancers are the most common recipient. The finding of TTM is often incidental during a biopsy of metastases or on surgical specimens but never suspected on radiological assessment of tumor extension. The finding of an unexpected region of Fluorodeoxyglucose (FDG) uptake can occur when performing whole body Positron Emission Tomography/computed tomography (PET/CT) scan and potentially raises the possibility of a second primary tumor. However, PET/CT scan incidental detection of tumor-to-tumor metastasis has never been reported in English literature. We report here a case of clear cell renal carcinoma, receptor of metastases originating from an oligometastatic squamous cell lung cancer detected on the PET/CT scan performed as part of the extension workup. Morphological and immunohistochemical analysis of a percutaneous biopsy of the renal mass were consistent with the diagnosis of a metastasis of lung cancer into renal cell carcinoma. This is the first case of oligometastatic lung cancer with the occurrence of TTM suspected in PET/CT scan. Although this is a rare setting, it should be considered in daily practice, as it could potentially modify the oncological management offered to the patients.     

Comparison of FDG-PET, MRI and CT for post radiofrequency ablation evaluation of hepatic tumors

Purpose

Treatment effect of radiofrequency ablation (RFA) is traditionally accomplished with MRI and/or CT. The aim of the study was to assess the role of FDG-PET in post RFA hepatic tumor evaluation, in comparison with MRI and CT.

Materials and methods

28 patients (33 hepatic RFA lesions) who had post RFA FDG-PET within 8 weeks of abdominopelvic MRI or CT were retrospectively reviewed. Accuracy of FDG-PET on post hepatic RFA evaluation was compared with MRI and/or CT based on clinical and imaging follow-up.

Results

Among total of 33 RFA-treated lesions, 17 had residual or recurrent tumor (positive). PET identified 16 with a sensitivity of 94.1 %. Of these 17 lesions, 12 had concurrent MRI and 8 were positive with a sensitivity of 66.7 %. Similarly, 6 out of the 17 lesions had CT and 4 were positive with a sensitivity of 66.7 %. Sixteen lesions were successfully ablated (negative). Among them FDG-PET was negative in 13 with a specificity of 81.3 %; MRI was performed in 8 and 7 were negative with a specificity of 87.5 %; CT was performed in 8 and 5 were negative with a specificity of 62.5 %. The overall accuracy of PET, MRI and CT was 87.9, 75.0, and 64.3 %, respectively. The average scan numbers for PET, MRI and CT to achieve a final accurate diagnosis were 1.121, 1.316 and 1.250, with a corresponding cost of $1455.2, $1845.8, and $933.8, respectively.

Conclusions

The study suggests that FDG-PET is superior to MRI and/or CT and is more cost-effective in post RFA hepatic tumor assessment.     

The usefulness of 18F-FDG PET/MRI fusion image in diagnosing pancreatic tumor: comparison with 18F-FDG PET/CT

Purpose

This study aimed at demonstrating the feasibility of retrospectively fused ¹⁸F FDG-PET and MRI (PET/MRI fusion image) in diagnosing pancreatic tumor, in particular differentiating malignant tumor from benign lesions. In addition, we evaluated additional findings characterizing pancreatic lesions by FDG-PET/MRI fusion image.

Methods

We analyzed retrospectively 119 patients: 96 cancers and 23 benign lesions. FDG-PET/MRI fusion images (PET/T1 WI or PET/T2WI) were made by dedicated software using 1.5 Tesla (T) MRI image and FDG-PET images. These images were interpreted by two well-trained radiologists without knowledge of clinical information and compared with FDG-PET/CT images. We compared the differential diagnostic capability between PET/CT and FDG-PET/MRI fusion image. In addition, we evaluated additional findings such as tumor structure and tumor invasion.

Results

FDG-PET/MRI fusion image significantly improved accuracy compared with that of PET/CT (96.6 vs. 86.6 %). As additional finding, dilatation of main pancreatic duct was noted in 65.9 % of solid types and in 22.6 % of cystic types, on PET/MRI-T2 fusion image. Similarly, encasement of adjacent vessels was noted in 43.1 % of solid types and in 6.5 % of cystic types. Particularly in cystic types, intra-tumor structures such as mural nodule (35.4 %) or intra-cystic septum (74.2 %) were detected additionally. Besides, PET/MRI-T2 fusion image could detect extra benign cystic lesions (9.1 % in solid type and 9.7 % in cystic type) that were not noted by PET/CT.

Conclusions

In diagnosing pancreatic lesions, FDG-PET/MRI fusion image was useful in differentiating pancreatic cancer from benign lesions. Furthermore, it was helpful in evaluating relationship between lesions and surrounding tissues as well as in detecting extra benign cysts.     

The current status of an FDG-PET cancer screening program in Japan, based on a 4-year (2006–2009) nationwide survey

Objective

The aim of this study was to survey the 18F-fluorodeoxyglucose-positron emission tomography (FDG-PET) cancer screening program conducted in Japan.

Methods

The “FDG-PET cancer screening program” included both FDG-PET and positron emission tomography with computed tomography (PET/CT) with or without other combined screening tests that were performed for cancer screening in asymptomatic subjects. A total of 155,456 subjects who underwent the FDG-PET cancer screening program during 2006–2009 were analyzed.

Results

Of the 155,456 subjects, positive findings suggesting possible cancer were noted in 16,955 (10.9 %). The number of cases with detected cancer was 1,912 (1.23 % of the total screened cases, annual range 1.14–1.30 %). Of the 1,912 cases of detected cancer, positive findings on FDG-PET were present in 1,491 cases (0.96 % of the total number of screened cases). According to the results of further examinations, the true positive rate for subjects with suggested possible cancer (positive predictive value) was 32.3 % with FDG-PET. Cancers of the colon/rectum, thyroid, lung, and breast were most frequently found (396, 353, 319, and 163 cases, respectively) with high PET sensitivity (85.9, 90.7, 86.8, 84.0 %, respectively). Prostate cancer and gastric cancer (165 and 124 cases, respectively) had low PET sensitivity (37.0 and 37.9 %, respectively). The Union for International Cancer Control (UICC) clinical stage of cancer found with the FDG-PET cancer screening program was mainly Stage I.

Conclusions

The FDG-PET screening program in Japan has detected a variety of cancers at an early stage. However, several cancers were found in repeated FDG-PET cancer screening program, indicating the limitation of a one-time FDG-PET cancer screening program. The value of the FDG-PET cancer screening program is left to the judgment of individuals with regard to its potentials and limitations.     

Additional value of integrated PET/CT over PET alone in the initial staging and follow up of head and neck malignancy

Objective

Clinical application of FDG-PET in head and neck cancer includes identification of metastases, unknown primary head and neck malignancy, or second primary carcinoma, and also recurrent tumor after treatment. In this study, the additional value of PET/CT fusion images over PET images alone was evaluated in patients with initial staging and follow up of head and neck malignancy.

Methods

Forty patients with suspected primary head and neck malignancy and 129 patients with suspected relapse after treatment of head and neck malignancy were included. FDG-PET/CT study was performed after the intravenous administration of FDG (5 MBq/kg). Target of evaluation was set at primary tumor, cervical lymph node, and whole body. PET images and PET with CT fusion images were compared. Sensitivity, specificity, accuracy, positive predictive value (PPV), and negative predictive value (NPV) were calculated. Results of PET and PET/CT were compared with postoperative histopathological examination, and case by case comparison of PET and PET/CT results for each region was performed. The additional value of CT images over PET only images was assessed. Statistical differences in sensitivity and specificity were evaluated.

Results

In the comparative evaluation of 507 targets by PET alone and PET/CT, 401 targets showed agreement of the results. Of the 106 discordant targets, 103 showed a positive result on PET alone and negative result on PET/CT. These results showed a significant difference (p < 0.01). Sensitivity of PET/CT was slightly higher than that of PET without statistical significance, while specificity of PET/CT was significantly higher than that of PET alone (Initial staging: 90.5% vs. 62.2%, p < 0.01; Follow up: 97.2% vs. 74.4%, p < 0.01). In Fisher’s direct probability test, a significant difference was noted in the sensitivity (Initial staging: 91.3% vs. 87.0%, p < 0.01; Follow up: 93.9% vs. 91.4%, p < 0.01).

Conclusions

Combined PET/CT showed improved diagnostic performance than PET alone by decreasing the number of false positive findings in patients with initial staging and follow up of head and neck malignancy.     

FDG-PET imaging for the staging and follow-up of small cell lung cancer

The staging procedures for small cell lung cancer do not differ appreciably from those for other forms of lung cancer. For practical purposes, the TNM stages are usually collapsed into a simple binary classification: limited disease and extensive disease. This study was performed to answer the question of whether fluorine-18 labelled 2-deoxy-2-D-glucose positron emission tomography (FDG-PET) imaging permits appropriate work-up (including both primary and follow-up staging) of patients presenting with small cell lung cancer, as compared with currently recommended staging procedures. Thirty-six FDG-PET examinations were performed in 30 patients with histologically proven small cell lung cancer. Twenty-four patients were examined for primary staging while four were imaged for therapy follow-up only. Two patients underwent both primary staging and up to four examinations for therapy follow-up. Static PET imaging was performed according to a standard protocol. Image reconstruction was based on an ordered subset expectation maximization algorithm including post-injection segmented attenuation correction. Results of FDG-PET were compared with those of the sum of other staging procedures. Identical results from FDG-PET and the sum of the other staging procedures were obtained in 23 of 36 examinations (62 limited disease, 122 extensive disease, 52 no evidence of disease). In contrast to the results of conventional staging, FDG-PET indicated extensive disease resulting in an up-staging in seven patients. In one patient in whom there was no evidence for tumour on conventional investigations following treatment, FDG-PET was suggestive of residual viability of the primary tumour. Furthermore, discordant results were observed in five patients with respect to lung, bone, liver and adrenal gland findings, although in these cases the results did not affect staging as limited or extensive disease. Moreover, FDG-PET appeared to be more sensitive for the detection of metastatic mediastinal and hilar lymph nodes and bone metastases. Finally, all findings considered suspicious for tumour involvement on the other staging procedures were also detected by FDG-PET. It is concluded that FDG-PET has potential for use as a simplified staging tool for small cell lung cancer.     

Modification of staging and treatment of head and neck cancer by FDG-PET/CT prior to radiotherapy

Background and purpose

Reliable tumor staging is a fundamental pre-requisite for efficient tumor therapy and further prognosis. The aim of this study was to compare head and neck cancer (HNC) staging before and after FDG-PET/CT, evaluating the stage modifications for radiotherapy (RT) planning.

Patients and methods

A total of 102 patients with untreated primary HNC, who underwent conventional staging and staging including FDG-PET/CT before RT, were enrolled in this retrospective study. Blinded pre-FDG-PET/CT and post-FDG-PET/CT staging data were compared. The impact on patient management was tested by comparing the intention before and after FDG-PET/CT.

Results

Significant modifications of T, N, and M stage as well as clinical stage were detected after inclusion of FDG-PET/CT data (p?=?0.002, 0.0006, 0.001, 0.03, respectively). Overall, the implementation of FDG-PET/CT led to modification of RT intention decision in 14 patients.

Conclusions

FDG-PET/CT demonstrates essential influence on tumor staging in HNC patients scheduled for irradiation. Implementation of FDG-PET/CT in imaging protocol improves selection of candidates for curative and palliative RT and allows further optimization of treatment management and therapy intention.     

From tumor biology to clinical PET: A review of positron emission tomography (PET) in oncology

Cancer cells show increased metabolism of both glucose and amino acids, which can be monitored with 18F-2-deoxy-2-fluoro-D-glucose (FDG), a glucose analogue, and 11C-L-methionine (Met), respectively. FDG uptake is higher in fast-growing than in slow-growing tumors. FDG uptake is considered to be a good marker of the grade of malignancy. Several studies have indicated that the degree of FDG uptake in primary lung cancer can be used as a prognostic indicator. Differential diagnosis of lung tumors has been studied extensively with both computed tomography (CT) and positron emission tomography (PET). It has been established that FDG-PET is clinically very useful and that its diagnostic accuracy is higher than that of CT. Detection of lymph node or distant metastases in known cancer patients using a whole-body imaging technique with FDG-PET has become a good indication for PET. FDG uptake may be seen in a variety of tissues due to physiological glucose consumption. Also FDG uptake is not specific for cancer. Various types of active inflammation showed FDG uptake to a certain high level. Understanding of the physiological and benign causes of FDG uptake is important for accurate interpretation of FDG-PET. In monitoring radio/chemotherapy, changes in FDG uptake correlate with the number of viable cancer cells, whereas Met is a marker of proliferation. Reduction of FDG uptake is a sensitive marker of viable tissue, preceding necrotic extension and volumetric shrinkage. FDG-PET is useful for the detection of recurrence and for monitoring the therapeutic response of tumor tissues in various cancers, including those of the lung, colon, and head and neck. Thus, PET, particularly with FDG, is effective in monitoring cancer cell viability, and is clinically very useful for the diagnosis and detection of recurrence of lung and other cancers.     

SUV<Subscript>max</Subscript> on FDG-PET is a predictor of prognosis in patients with maxillary sinus cancer

Purpose

Our aim was to determine whether the maximum standardized uptake value (SUV_max) of the primary lesion demonstrated by [¹⁸F]-fluoro-2-deoxyglucose positron emission tomography/computed tomography (FDG-PET/CT) is associated with the prognosis of maxillary sinus cancer.

Materials and methods

The relationships of clinicopathological factors including age, T stage, N stage, histologic type, treatment strategy, and primary tumor SUV_max with progression-free (PFS) and overall (OS) survival were evaluated using the log-rank test and Cox method in 31 patients with maxillary sinus cancer before combined superselective intra-arterial chemotherapy using high-dose cisplatin with concurrent radiotherapy, or radiotherapy alone.

Results

The median duration of follow-up was 55.4 (range 9.7–72.6) months. PFS and OS of patients exhibiting a high SUV_max (≥16 and ≥17, respectively) for the primary tumor were significantly lower than those of patients for whom the primary tumor SUV_max was low (p = 0.0010 and p = 0.033, respectively). Multivariate analyses showed that T stage (p = 0.0049) and primary tumor SUV_max (p = 0.026) were independently prognostic of poorer PFS and that only primary tumor SUV_max (p = 0.049) was independently prognostic of poorer OS.

Conclusion

SUV_max of the primary tumor determined by FDG-PET/CT before treatment could be a good surrogate marker for prognostication of maxillary sinus cancer.

     

Current status of nuclear medicine clinical application of FDG-PET for cancer diagnosis. Lung cancer

Recent advances in small cyclotrons, PET scanners, and image-processing software have made it possible to apply FDG-PET for clinical use, especially for tumor imaging. Although the efficacy of FDG-PET for several tumors remains a problem under discussion, the efficacy of PET for lung cancer has been studied in great detail and has already been established. The roles of FDG-PET for lung cancer management are, roughly speaking, 1) characterization of pulmonary nodules, 2) staging of lung cancer, 3) monitoring therapeutic effect, and 4) early diagnosis of tumor recurrence. We examined the usefulness of FDG-PET for lung cancer by analyzing our own data and reviewing recent reports. Two image-processing techniques, the image fusion technique and the respiratory-gated data-acquisition method, are also introduced in this article. FDG-PET is a promising method of anatomical imaging that is complementary to such techniques as CT and MRI. It may obtain a more important position among imaging modalities in the future.