TNM staging update for lung cancer: Why is this important?

Cancer staging characterises the extent of disease facilitating selection of the most appropriate management and therapy and providing prediction of prognosis.As understanding of lung cancer evolves the opportunities arises to adjust disease staging.The adoption of the 7th edition tumour,node,metastasis staging system should result in improved treatment selection and more accurate prognostic information for the individual patient.     

A method of adjusting SUV for injection-acquisition time differences in 18 F-FDG PET Imaging

Objective  

A time normalisation method of tumour SUVs in ¹⁸ F-FDG PET imaging is proposed that has been verified in lung cancer patients.     

Whole‐body PET/MRI for colorectal cancer staging: Is it the way forward?

Magnetic resonance imaging (MRI) is presently the modality of choice for the local staging of rectal cancer, with positron emission tomography (PET) being optional for the evaluation of colorectal cancer. Indeed, previous studies have demonstrated that liver MRI using hepatocyte‐specific contrast agents can provide high diagnostic performance in the detection of colorectal cancer liver metastases. Recently, however, whole‐body PET/MRI, which can provide information regarding both anatomy and metabolism, has been introduced to clinical imaging, and studies are under way to assess whether it can improve diagnostic performance for oncologic diseases as well as provide additional information regarding the disease phenotype and biology compared to conventional imaging modalities of computed tomography (CT), PET, or MRI. This review offers a brief overview of the technical considerations of the PET/MRI system, and the current status of imaging modalities in the staging of colorectal cancer. The potential of whole‐body PET/MRI to improve the performance of colorectal cancer staging and the results of several recent studies will be discussed, and workflow considerations of whole‐body PET/MRI for patients with colorectal cancer will be addressed. Level of Evidence: 5 J. Magn. Reson. Imaging 2017;45:21–35.     

Diffusion-weighted imaging as part of hybrid PET/MRI protocols for whole-body cancer staging: Does it benefit lesion detection?

Purpose

Positron emission tomography/magnetic resonance imaging (PET/MRI) requires efficient scan protocols for whole-body cancer staging. The aim of this study was to evaluate if the application of diffusion-weighted MR imaging (DWI) results in a diagnostic benefit for lesion detection in oncologic patients if added to a whole-body [18F]-fluorodesoxyglucose ([18F]-FDG) PET/MRI protocol.

Methods

25 consecutive oncologic patients (16 men, 9 women; age 57 ± 12 years) prospectively underwent whole-body [18F]-FDG-PET/MRI including DWI on a hybrid PET/MRI scanner. A team of two readers assessed [18F]-FDG PET/MRI without DWI for primary tumors and metastases. In a second session, now considering DWI, readers reassessed [18F]-FDG PET/MRI accordingly. Additionally, the lesion-to-background contrast on [18F]-FDG PET and DWI was rated qualitatively (0, invisible; 1, low; 2, intermediate; 3, high). Wilcoxon's signed-rank test was performed to test for differences in the lesion-to-background contrast.

Results

49 lesions were detected in 16 patients (5 primaries, 44 metastases). All 49 lesions were concordantly detected by [18F]-FDG PET/MRI alone and [18F]-FDG PET/MRI with DWI. The lesion-to-background contrast on DWI compared to [18F]-FDG PET was rated lower in 22 (44.9%) of 49 detected lesions resulting in a significantly higher lesion-to-background contrast on [18F]-FDG PET compared to DWI (P = 0.001).

Conclusions

DWI as part of whole-body [18F]-FDG PET/MRI does not benefit lesion detection. Given the necessity to optimize imaging protocols with regard to patient comfort and efficacy, DWI has to be questioned as a standard tool for whole-body staging in oncologic PET/MRI.     

Functional imaging of lung cancer using dual energy CT: how does iodine related attenuation correlate with standardized uptake value of 18FDG-PET-CT?

Objectives

To investigate the correlation between maximum standardized uptake value (SUV_max) of ¹⁸FDG PET-CT and iodine-related attenuation (IRA) of dual energy CT (DECT) of primary tumours and ¹⁸FDG PET-CT positive thoracic lymph nodes (LN) in patients with lung cancer.

Methods

37 patients with lung cancer (27 NSCLC, 10 SCLC, 86 ¹⁸FDG PET-CT positive thoracic LN) who underwent both ¹⁸FDG PET-CT and DECT were analyzed. The mean study interval between ¹⁸FDG PET-CT and DECT was ??21?days in 17 patients. The mean and maximum IRA of DECT as well as of virtual unenhanced and virtual 120?kV images of DECT was analyzed and correlated to the SUV_max of ¹⁸FDG PET-CT in all tumours and ¹⁸FDG PET-CT positive thoracic lymph nodes. Further subgroup analysis was performed for histological subtypes in all groups.

Results

A moderate correlation was found between SUV_max and maximum IRA in all tumours (n?=?37;r?=?0.507;p?=?0.025) whereas only weak or no correlation were found between SUV_max and all other DECT measurements. A strong correlation was found in patients with study intervals ??21?days (n?=?17; r?=?0.768;p?=?0.017). Analysis of histological subtypes of lung cancer showed a strong correlation between SUV_max and maximum IRA in the analysis of all patients with NSCLC (r?=?0.785;p?=?0.001) and in patients with NSCLC and study intervals ??21?days (r?=?0.876;p?=?0.024). Thoracic LN showed moderate correlation between SUV_max and maximum IRA in patients with study intervals ??21?days (r?=?0.654; p?=?0.010) whereas a weak correlation was found between SUV_max and maximum IRA in patients with study intervals >21?days (r?=?0.299; p?=?0.035).

Conclusions

DECT could serve as a valuable functional imaging test for patients with NSCLC as the IRA of DECT correlates with SUV_max of ¹⁸FDG PET-CT.     

Assessment of pulmonary melanoma metastases with 18F-FDG PET/CT: which PET-negative patients require additional tests for definitive staging?

Objectives

To determine, in patients with melanoma, the dependence of PET sensitivity on pulmonary metastasis size, and to determine patients who require further evaluation for definite staging.

Methods

Of 183 melanoma patients who underwent ¹⁸F-fluorodeoxyglucose PET/computed tomography (CT) for staging or follow-up between January 2008 and June 2011, 38 patients (18 women and 20 men; mean age 62.0?±?14.7?years) with one or more pulmonary metastases visible on CT were included in the retrospective study. Each pulmonary metastasis was rated as positive or negative on PET, and lesion size (maximum transverse diameter) was assessed on CT. PET sensitivity was calculated according to the lesions’ size, in 2-mm steps.

Results

A total of 181 pulmonary metastases were analysed. PET sensitivity was 7.9?% for lesions of 4–5?mm; 33.3?% for lesions of 6–7?mm; 56.8?% for lesions of 8–9?mm; 63.6?% for lesions of 10–11?mm; 100?% for lesions of 12–14?mm; and 100?% for lesions of at least 15?mm. The differences in sensitivity between the size groups were significant (P?<?0.001)

Conclusions

With current state-of-the-art PET/CT technology, additional tests are necessary for definitive staging of melanoma patients who have one or more PET-negative lung nodules less than 12?mm in diameter on expiratory CT.

Key Points

? PET cannot rule out malignancy in pulmonary nodules less than 12?mm on expiratory CT. ? Melanoma patients with PET-negative pulmonary nodules less than 12?mm require additional tests. ? Knowledge of these factors can help interpretation of PET and PET/CT findings.     

Detection of bone metastases in thyroid cancer patients: bone scintigraphy or 18F-FDG PET?

BACKGROUND: Similar to the situation in other tumour types, it is currently unclear whether fluorodeoxyglucose (FDG) positron emission tomography (PET) is adequate in the detection of bone metastases of thyroid cancer. The purpose of this retrospective study was to evaluate the performance of bone scans in comparison with FDG PET in the detection of bone metastases in patients with differentiated thyroid cancer (DTC). MATERIALS AND METHODS: Twenty-four patients had undergone both FDG PET and bone scans within 6 months because of suspected bone metastases. All scans were re-evaluated using all available additional imaging and clinical data for verification. Scan findings were scored as positive, negative or doubtful. RESULTS: Bone metastases were present in eight of 24 (33%) patients. Only bone scintigraphy but not FDG PET suggested the presence of bone metastases in three patients, all confirmed with magnetic resonance imaging (MRI)/X-ray. Five patients were identified with bone metastases on both bone scan and FDG PET, which was confirmed by computed tomography (CT)/MRI/X-ray in four. Five patients had doubtful findings on bone scans whereas FDG PET scans were negative. MRI showed degenerative disorders in two of five and was normal in two. Eleven patients had both a negative bone scan and FDG PET scan. CONCLUSION: In three of eight (38%) thyroid cancer patients bone metastases were only identified on bone scans. Therefore, bone scans are still valuable in detecting bone metastases in patients with DTC and can not be replaced by FDG PET.     

Development of a nomogram combining clinical staging with <Superscript>18</Superscript>F-FDG PET/CT image features in non-small-cell lung cancer stage I–III

Purpose

Our goal was to develop a nomogram by exploiting intratumour heterogeneity on CT and PET images from routine ¹⁸F-FDG PET/CT acquisitions to identify patients with the poorest prognosis.

Methods

This retrospective study included 116 patients with NSCLC stage I, II or III and with staging ¹⁸F-FDG PET/CT imaging. Primary tumour volumes were delineated using the FLAB algorithm and 3D Slicer? on PET and CT images, respectively. PET and CT heterogeneities were quantified using texture analysis. The reproducibility of the CT features was assessed on a separate test–retest dataset. The stratification power of the PET/CT features was evaluated using the Kaplan-Meier method and the log-rank test. The best standard metric (functional volume) was combined with the least redundant and most prognostic PET/CT heterogeneity features to build the nomogram.

Results

PET entropy and CT zone percentage had the highest complementary values with clinical stage and functional volume. The nomogram improved stratification amongst patients with stage II and III disease, allowing identification of patients with the poorest prognosis (clinical stage III, large tumour volume, high PET heterogeneity and low CT heterogeneity).

Conclusion

Intratumour heterogeneity quantified using textural features on both CT and PET images from routine staging ¹⁸F-FDG PET/CT acquisitions can be used to create a nomogram with higher stratification power than staging alone.

     

A case of non-Hodgkin’s lymphoma of the ovary: Usefulness of18F-FDG PET for staging and assessment of the therapeutic response

Primary ovarian lymphoma as the initial manifestation is rare. A 27-year-old woman presented to our hospital with the symptoms of lower abdominal fullness and pollakisuria. CT scan and MRI revealed bilateral ovarian tumors, which showed heterogeneous masses. 18F-FDG PET revealed strong uptake by the abdominal masses, and the maximum standardized uptake value (SUVmax) was 12.5. Abnormal uptake was not shown by other regions. An exploratory laparotomy was performed. Histological findings revealed diffuse large B-cell lymphoma. The clinical stage was IV according to the Ann Arbor system. International prognostic index (IPI) was 3 (high-intermediate risk). Chemotherapy was administered consisting of three courses of an R-CHOP regimen, and 18F-FDG PET and CT scan revealed no signs of involvement 3 months after initiation of the chemotherapy. 18F-FDG PET was a useful method for staging and assessment of the therapeutic response in primary ovarian lymphoma.     

<Superscript>18</Superscript>F-FDG PET for the lymph node staging of non-small cell lung cancer in a tuberculosis-endemic country: <Emphasis Type="Italic">Is dual time point imaging worth the effort?</Emphasis>

PURPOSE: This study was to compare (18)F-FDG positron emission tomography (PET) with thoracic contrast-enhanced CT (CECT) in the ability of lymph node (LN) staging non-small cell lung cancer (NSCLC) in a tuberculosis-prevalent country. The usefulness of dual time point PET imaging (DTPI) in NSCLC nodal staging was also evaluated. METHODS: We reviewed 96 NSCLC patients (mean age, 65.3 +/- 11.7 years) who had received PET studies before their surgery. DTPI were performed on 37 patients (mean age, 64.8 +/- 12.2 years) who received an additional scan of thorax 3 h after tracer injection. The accuracies of nodal staging by CECT and PET were evaluated according to final histopathology of hilar and mediastinal LN resected by surgery. RESULTS: The accuracy for nodal staging by CECT was 65.6% and that by PET was 82.3% (p < 0.05). Six patients were over-staged and 11 were under-staged by PET. Tuberculosis (n = 3, 50%) were mostly responsible for false-positive, while small tumor foci (n = 7, 63.6%) were mostly accountable for false-negative. For the 37 patients with DTPI, 45 min standardized uptake value (SUV) and 3 h SUV for negative LNs are significantly lower than those for positive LNs (p < 0.0001). Nevertheless, the retention index (RI) showed no significant difference between these two groups. CONCLUSIONS: Our study demonstrates that PET is more accurate than CECT in LN staging NSCLC patients in Taiwan where TB is still prevalent. Semi-quantitative SUV method or DTPI with RI does not result in better diagnostic accuracy than visual analysis of PET images.     

Whole-body 18F-FDG PET/CT for M staging in the patient with newly diagnosed nasopharyngeal carcinoma: Who needs?

ObjectiveAlthough whole-body fluorine-18 fluorodeoxyglucose (¹⁸F-FDG) positron emission tomography (PET)/computed tomography (CT) (¹⁸F-FDG PET/CT) is commonly used for M staging of newly diagnosed nasopharyngeal carcinoma (NPC), some patients may not benefit from this procedure. The present study investigated which patients require this modality for M staging.MethodsWhole-body ¹⁸F FDG PET/CT results and clinical data were collected for 264 patients with newly diagnosed NPC. The relationships between distant metastasis and age, gender, pathological type, lesion size, SUVmax-T, T staging, N staging, SUVmax-N and Epstein-Barr virus (EBV) quantity were retrospectively analysed to identify factors associated with increased risk.ResultsOf the 264 patients, only 37 (14.0%) were diagnosed with distant metastasis. Using multiple logistic regression analysis, EBV-positivity (OR = 13.1; 95% CI:1.61,106.80), N staging (OR = 3.05; 95% CI:1.41,6.63) and T staging (OR = 2.16; 95% CI:1.10, 4.24) were significantly related to distant metastasis (all P < 0.05). EBV DNA levels ≥ 9000 copies/ml, N3 stage and T4 stage were identified as high risk factors. A low risk of distant metastasis was found in patients with 0–1 risk factors and in those with 2 specific risk factors, T3/T4 and N2/N3 staging. Patients with EBV DNA levels ≥9000 copies/ml and N3 or T4 staging and those with 3 risk factors had a medium or high risk, with a much higher incidence of distant metastasis (χ² = 29.896, P = 0.000), and needed a whole-body ¹⁸F FDG PET/CT for M staging.ConclusionsDue to the low incidence of distant metastasis, only patients with medium or high risk need to undergo a whole-body scan.     

Information of prostate biopsy positive core: does it affect MR detection of prostate cancer on using 3T-MRI?

Objective

We assessed which information from a prostate biopsy had the strongest relationship with prostate cancer detection by 3T-MRI.

Materials and methods

Sixty-one consecutive patients with biopsy-proven prostate cancer who underwent 3T-MRI before biopsy were enrolled in this retrospective study. Two radiologists independently reviewed T2-weighted and diffusion-weighted images. When the cancer lesions were revealed by biopsy and MRI depicted them at corresponding sites, we classified these lesions as MRI-detectable cancer. If the cancer lesions were revealed by biopsy, but any cancers had not been detected, we classified these lesions as MRI-undetectable cancer. We compared the Gleason score (GS), cancer ratio (CaR) and cancer length (CaL) from core biopsies between the two groups.

The results

GS, CaR and CaL differed significantly between the MRI-detectable group (N = 70), and the MRI-undetectable group (N = 73). 3T-MRI could detect cancer cores with a sensitivity of 90.5 % in cores with CaR ≥ 60 %, and with a sensitivity of 81.8 % in those with CaL ≥ 5 mm. Receiver operating characteristic analysis showed that CaR (P = 0.006) and CaL (P = 0.010) significantly associated with the prostate cancer detection using MRI rather than GS.

Conclusion

CaR and CaL from the core biopsies showed a stronger relationship to detection of the prostate cancer on 3T-MRI than the GS did.