18F-FDG Uptake at Initial Staging of the Adrenocortical Cancers: A Diagnostic Tool but Not of Prognostic Value

Background

Adrenocortical carcinoma (ACC) is a rare cancer for which little level evidence exists to guide management. ¹⁸F-FDG PET (¹⁸F-fluorodeoxyglucose positron emission tomography) is an increasingly used diagnostic tool in patients with suspicious or indeterminate adrenal tumors. In some other solid tumors, ¹⁸F-FDG PET may offer prognostic information that can guide optimal patient treatment. The aim of the present study was to evaluate whether preoperative ¹⁸F-FDG PET based on SUVs assessments has a prognostic value in ACC patients.

Methods

A retrospective analysis was performed in patients who underwent ¹⁸F-FDG PET/CT for the evaluation of ACC. Inclusion criteria were an unequivocal diagnosis of ACC; all data from primary diagnosis available; ¹⁸F-FDG PET/CT performed prior to surgery or other treatment of the primary tumor; a minimum of 6-months follow-up for surviving patients. All ¹⁸F-FDG PET/CT procedures were reinterpreted in a blind fashion.

Results

Thirty-seven patients (23 without metastasis [M0], 14 with metastasis [M1]) fulfilled the study criteria. Median uptake values were tumor standardized uptake values (SUV)_max = 11 (range: 3–56) and a tumor/liver SUV_max ratio = 4.2 (range: 1.3–15). Median follow-up was 20 months. Although classic risk factors (tumoral stage, Weiss score) were associated with poor outcome, there was no correlation between primary tumor FDG uptake with overall survival (OS) and disease free survival (DFS) in M0 patients and with overall survival in M1 patients. ¹⁸F-FDG uptake correlated inconsistently with sinister histological features, such as atypical mitoses or necrosis.

Conclusions

At initial staging, primary tumor FDG uptake in ACC patients does not correlate with OS and DFS at 2 years. Patient prognosis and treatment strategy should not be based on uptake values.     

Utility of 18F-FDG PET/CT for Detecting Neck Metastasis in Patients with Salivary Gland Carcinomas: Preoperative Planning for Necessity and Extent of Neck Dissection

Background:

The precise diagnosis of cervical lymph node metastasis (CLNM) of salivary gland cancer is important to determine the surgical extent and adjuvant therapy. This study assessed the clinical utility of ¹⁸F-FDG PET in identifying CLNM in such patients.

Methods:

Fifty-four patients with intermediate or high-grade salivary gland cancer were preoperatively evaluated with ¹⁸F-FDG PET/CT and CT/MRI. Histopathologic analysis of neck dissection tissues was used as the gold standard for assessing imaging techniques. Tumor and nodal maximum standardized uptake values (SUVmax) were measured for each patient. Univariate and multivariate analyses were used to identify CLNM predictive factors.

Results:

Of the 54 patients, 24 patients (44 %) had CLNM. On a per-patient basis, the sensitivity and specificity of ¹⁸F-FDG PET/CT and CT/MRI were not significantly different (92 vs. 83 %, P = 0.625 and 93 vs. 97 %, P = 1.000, respectively). On a per-level basis, ¹⁸F-FDG PET/CT was significantly more sensitive and accurate than CT/MRI in the ipsilateral neck (96 vs. 54 %, P < 0.001 and 92 vs. 83 %, P < 0.001, respectively). The mean nodal SUVmax values of patients with and without nodal metastasis were 4.9 and 2.1, respectively (P = 0.008). Histologic grade was a significant predictor of CLNM (P = 0.014, odds ratio 14.46, 95 % confidence interval 1.73–120.79).

Conclusions:

¹⁸F-FDG PET/CT imaging and histologic grade are useful for detecting CLNM in patients with salivary gland carcinoma. This finding may guide preoperative planning for the necessity and extent of neck dissection in these patients.     

18F-FAMT-PET Is Useful for the Diagnosis of Lymph Node Metastasis in Operable Esophageal Squamous Cell Carcinoma

Background

The role and potential usefulness of positron emission tomography (PET) scanning in certain tumors has been widely investigated in recent years. ¹⁸F-FAMT (L-[3-¹⁸F]-α-methyltyrosine) is an amino acid tracer for PET. This study investigated whether PET/CT with ¹⁸F-FAMT provides additional information for preoperative diagnostic workup of esophageal squamous cell carcinoma compared with that obtained by ¹⁸F-FDG (fluorodeoxyglucose) PET or CT.

Methods

PET/CT studies with ¹⁸F-FAMT and ¹⁸F-FDG were performed as a part of the preoperative workup in 21 patients with histologically confirmed esophageal squamous cell carcinoma.

Results

For the detection of primary esophageal cancer, ¹⁸F-FAMT-PET exhibited a sensitivity of 76.2%, whereas the sensitivity for ¹⁸F-FDG-PET was 90.5% (P = 0.214). ¹⁸F-FAMT uptake in primary tumors showed significant correlation with depth of invasion (P = 0.005), lymph node metastasis (P = 0.045), stage (P = 0.031), and lymphatic invasion (P = 0.029). In the evaluation of individual lymph node groups, ¹⁸F-FAMT-PET exhibited 18.2% sensitivity, 100% specificity, 71.9% accuracy, 100% positive predictive value, and 70.0% negative predictive value, compared with 24.2%, 93.7%, 69.8%, 66.6%, and 70.2%, respectively, for ¹⁸F FDG-PET. CT exhibited 39.4% sensitivity, 85.7% specificity, 69.8% accuracy, 59.1% positive predictive value, and 73.0% negative predictive value. The specificity of ¹⁸F-FAMT-PET is significantly higher than that of ¹⁸F-FDG-PET (P = 0.042) and CT (P = 0.002). ¹⁸F-FAMT-PET did not have any false-positive findings compared to those with ¹⁸F-FDG-PET.

Conclusions

Our findings suggest that the addition of ¹⁸F-FAMT-PET to ¹⁸F-FDG-PET and CT would permit more precise staging of esophageal cancer.     

Early Assessment of Axillary Response with 18F-FDG PET/CT during Neoadjuvant Chemotherapy in Stage II–III Breast Cancer: Implications for Surgical Management of the Axilla

Background

If all initially node-positive patients undergo axillary lymph node dissection (ALND) after neoadjuvant chemotherapy (NAC), overtreatment may occur in patients with complete response. Positron emission tomography–computed tomography (PET/CT) during NAC may predict axillary response and select patients appropriate for less invasive treatment after NAC. We evaluated the value of sequential ¹⁸F fluorodeoxyglucose (FDG) PET/CTs during NAC for axillary response monitoring in stage II–III breast cancer.

Methods

A total of 219 PET/CTs were performed in 80 patients with cytology-proven, node-positive disease at baseline (PET/CT1, n = 80) and twice during NAC (PET/CT2 n = 62, PET/CT3, n = 77). The relative changes in maximum standardized uptake value (SUV_max) of axillary nodes were examined for their ability to assess pathological response. All patients underwent ALND after chemotherapy, and complete axillary response (pCR), defined as absence of isolated tumor cells and of micro- and macrometastases, served as the reference standard.

Results

A total of 32 (40 %) patients experienced axillary pCR. The relative decrease in SUV_max was significantly higher in patients with pCR than in those without, both on PET/CT2 (p < 0.001) and PET/CT3 (p = 0.025). The area under the receiver operating characteristic curve values for PET/CT2 and PET/CT3 were 0.80 (95 % confidence interval 0.68–0.92) and 0.65 (95 % confidence interval 0.52–0.79), respectively. A relative decrease of ≥60 % on PET/CT2 had an excellent specificity (35 of 37, 95 %), a high positive predictive value (12 of 14, 86 %), and a sensitivity of 48 %—that is, it accurately identified histologic pCR in 12 of 25 patients with disease that responded to therapy.

Conclusions

¹⁸F-FDG PET/CT early during NAC is useful for axillary response monitoring in cytology-proven node-positive breast cancer because it identifies pathological response, thus permitting ALND to be spared.     

Acute exacerbation of interstitial lung disease with lung cancer after surgery: evaluation with 2-[18]-fluoro-2-deoxy-d-glucose positron emission tomography

Purpose

Interstitial lung disease (ILD) has been associated with primary lung cancer and an increased risk of postoperative acute exacerbation (AE). The effectiveness of 2-[18]-fluoro-2-deoxy-d-glucose (¹⁸F-FDG) positron emission tomography (PET) for staging lung cancer is well established. This study investigates the association of FDG uptake on PET in patients with AE of ILD.

Methods

The subjects of this retrospective study were 1309 patients with lung cancer, who underwent pulmonary resection at Shizuoka Cancer Center between September, 2002 and January, 2011. ILD was diagnosed with chest computed tomography in 95 patients, 81 of whom underwent ¹⁸F-FDG PET before surgery. Six patients suffered from AE after surgery (AE group), while the remaining 75 (non-AE group) did not. We investigated the clinico-pathological findings and the results of FDG uptake on PET using the value of the I/M ratio, which is the ratio of the peak of standardized uptake value (SUV) of the ILD area to the mean SUV of the mediastinum.

Results

There was no significant difference in clinico-pathological findings, but a significance difference in the I/M ratio (P = 0.0102).

Conclusion

The FDG uptake in PET may be a predictive factor for AE of ILD in patients who have undergone lung cancer surgery.     

Impact of total PSA, PSA doubling time and PSA velocity on detection rates of 11C-Choline positron emission tomography in recurrent prostate cancer

Purpose

To evaluate the effect of total PSA (tPSA) and PSA kinetics on the detection rates of ¹¹C-Choline PET in patients with biochemical recurrence (BCR) after radical prostatectomy (RP) or external beam radiotherapy (EBRT).

Methods

We included 185 patients with BCR after RP (PSA >0.2 ng/ml) or after EBRT (ASTRO definition). After injection of 400 MBq ¹¹C-Choline i.v., a scan was made using the ECAT HR + PET camera with CT fusion images or Siemens mCT PET/CT. Biopsy-proven histology, confirmative imaging (CT or bone scan) and/or clinical follow-up (PSA) were used as composite reference. Statistical analysis was performed using PASW Statistics 18.

Results

¹¹C-Choline PET was positive in 124/185 cases (65 %) (in 22/61 (36 %) after RP, 102/124 (82 %) after EBRT). In 79 patients a local recurrence was identified, and 45 patients showed locoregional metastases on PET/CT. In 20 cases a proven false-negative PET scan was observed. Positive PET scans were confirmed by histology in 87/124 (70 %) cases, by confirmatory imaging in 34/124 (28 %) and by clinical follow-up after salvage treatment in 3 (2 %) cases. The ROC analysis to detect a recurrence showed significant difference in area under the curve (AUC) of tPSA 0.721(p < 0.001) and PSA velocity 0.730 (p < 0.001). PSA doubling time showed no significant difference with an AUC of 0.542 (p = 0.354). Detection rates are <50 % in tPSA <2 ng/ml and/or PSA velocity <1 ng/ml/year.

Conclusions

Total serum PSA and PSA velocity have significant effect on the detection rates of ¹¹C-Choline PET/CT in men with a BCR after RP or EBRT.     

18F-fluorocholine PET/CT compared with extended pelvic lymph node dissection in high-risk prostate cancer

Purpose

To compare ¹⁸F-fluorocholine positron-emission tomography/computed tomography (PET/CT) with extended pelvic lymph node dissection (ePLND) for the detection of lymph node metastases in a large cohort of patients with high-risk prostate cancer.

Materials and methods

Patients with prostate-specific antigen levels between 20 and 99 ng/mL and/or Gleason score 8–10 cancers, planned for treatment with curative intent following a negative or inconclusive standard bone scan, were investigated with ¹⁸F-fluorocholine PET/CT followed by an ePLND. None of the patients received hormonal therapy prior to these staging procedures. Results for PET/CT were compared on a per-patient basis with histopathology from ePLND. Sensitivity, specificity, positive and negative predictive values were calculated.

Results

PET/CT detected a total of 76 suspected lymph node metastases and four suspected bone metastases in 33 (29 %) of the 112 included patients. Of these, 35 suspected lymph node metastases, only within the anatomical template area of an ePLND, were found in 21 of the patients. Histopathology of the ePLND specimens detected 117 lymph node metastases in 48 (43 %) of the 112 patients. Per-patient sensitivity, specificity, positive and negative predictive values for ¹⁸F-fluorocholine PET/CT for lymph node metastases within the ePLND template were 0.33, 0.92, 0.76 and 0.65, respectively. Only 11 patients had lymph nodes larger than 10 mm that would have been reported by CT alone.

Conclusions

¹⁸F-fluorocholine PET/CT detects lymph node metastases in a significant proportion of patients with high-risk prostate cancer with a high specificity, but low sensitivity.     

18F-FDG-PET/CT to Select Patients with Peritoneal Carcinomatosis for Cytoreductive Surgery and Hyperthermic Intraperitoneal Chemotherapy

Background

Cytoreductive surgery followed by hyperthermic intraperitoneal chemotherapy (HIPEC) is associated with significantly longer survival in patients with peritoneal carcinomatosis (PC). So far, no morphological imaging method has proven to accurately assess the intra-abdominal tumor spread. This study was designed to predict tumor load in patients with PC using dual-modality ¹⁸FDG-PET/CT and to compare the results with those of PET and CT alone by correlating imaging findings with intraoperative staging.

Methods

Twenty-two patients with PC from gastrointestinal (n = 13), ovarian cancer (n = 8), and mesothelioma (n = 1) underwent contrast-enhanced ¹⁸FDG-PET/CT before surgery and HIPEC. In a retrospective analysis PET, CT, and fused PET/CT were separately and blindly reviewed for the extent of peritoneal involvement using the Peritoneal Cancer Index (PCI). Imaging results were correlated with the intraoperative PCI using Pearson’s correlation coefficient and linear regression analysis.

Results

There was a strong correlation between the PCI obtained with PET/CT and the surgical PCI with respect to the total score (r = 0.951) as well as in the regional analysis (small bowel, r = 0.838; other, r = 0.703). The correlation was slightly lower for CT alone (total score, r = 0.919; small bowel, r = 0.754; other, r = 0.666) and significantly lower (p = 0.002) for PET alone (total score, r = 0.793; small bowel, r = 0.553, other, 0.507).

Conclusions

Contrast-enhanced CT is superior compared with PET alone to predict the extent of PC. In our patient group, the combination of both modalities (contrast enhanced PET/CT) yielded the best results and proved to be a useful tool for selecting candidates for peritonectomy and HIPEC.     

Lymph-node metastases in rectal carcinoids

Background

Colorectal carcinoids are described as low-grade malignancy in the WHO classification. However, the survival is equally poor between carcinoids and adenocarcinomas if the tumors have lymph node metastasis or distant metastasis.

Patients and methods

We reviewed 17 patients with rectal carcinoid, who underwent surgical resection with lymph node dissection at our institution between March 2005 and November 2007. Our criteria for surgical resection were: tumor size of 10 mm or larger and positive resection margin or the presence of lymphovascular invasion in lesions to which endoscopic or surgical local treatment was carried out.

Results

Lymph node metastases were present in 12 patients. Three of them were with tumors less than 10 mm in size, of whom two patients had lymphovascular invasion. In eight out of the 12 with lymph node metastases, preoperative computed tomography (CT) identified lymph nodes of 5 mm or larger in size.

Conclusions

The present study demonstrated that rectal carcinoids with lymph node metastasis are common. Previously reported risk factors of lymph node metastasis in rectal carcinoid such as tumor size >?=?10 mm and lymphovascular invasion are useful in predicting lymph node metastasis. In addition, lymph nodes 5 mm or larger in size identified on preoperative CT suggest the presence of metastasis.     

Metabolic Response to Preoperative Chemotherapy Predicts Prognosis for Patients Undergoing Surgical Resection of Colorectal Cancer Metastatic to the Liver

Background

Biological characteristics of colorectal cancer liver metastases (CRCLM) are increasingly recognized as major determinants of patient outcome. The purpose of this study was to evaluate the prognostic value of metabolic response to preoperative chemotherapy as quantified by ¹⁸F-FDG positron emission tomography (PET) for patients undergoing liver resection of CRCLM.

Methods

All patients (n = 80) who had staging PET before liver resection for CRCLM at Austin Health in Melbourne between 2004 and 2011 were included. Thirty-seven patients had PET and CT imaging before and after preoperative chemotherapy. Semiquantitative PET parameters—maximum standardized uptake variable (SUV_max), metabolic tumour volume (MTV), and total glycolytic volume (TGV)—were derived. Metabolic response was determined by the proportional change in PET parameters (?SUV_max, ?MTV, ?TGV). Prognostic scores, CT RECIST response, and tumour regression grading (TRG) were also assessed. Correlation to recurrence-free (RFS) and overall survival (OS) was assessed using Kaplan–Meier survival and multivariate analysis.

Results

Semiquantitative parameters on staging PET before chemotherapy were not predictive of prognosis, whereas all parameters after chemotherapy were prognostic for RFS and OS. Only ?SUV_max was predictive of RFS and OS on multivariate analysis. Patients with metabolically responsive tumours had an OS of 86 % at 3 years vs. 38 % with nonresponsive or progressive tumours (p = 0.003). RECIST and TRG did not predict outcome.

Conclusions

Tumour metabolic response to preoperative chemotherapy as quantified by PET is predictive of prognosis in patients undergoing resection of CRCLM. Assessing metabolic response uniquely characterizes tumour biology, which may allow future optimization of patient and treatment selection.     

Diagnostic value of 18F-FDG PET/CT for lymph node metastasis of esophageal squamous cell carcinoma

Purpose

This study investigated the diagnostic accuracy of hybrid positron-emission tomography/computed tomography (PET/CT) for lymph node (LN) metastasis of esophageal cancer. We also investigated the correlation between the size of metastatic nests and the detection by PET/CT.

Methods

Two hundred and fifty-eight patients with esophageal squamous cell carcinoma who underwent esophagectomy with two- or three-field radical lymphadenectomy were analyzed retrospectively. We compared the diagnosis of preoperative PET/CT to the postoperative histopathological examination by each anatomical field (n = 1,231) in all 258 patients. The metastatic LNs resected from PET/CT positive fields were classified as belonging to the PET/CT-N-positive group (n = 229) and those from negative fields as belonging to the PET/CT-N-negative group (n = 352). The cross-sectional areas of metastatic nests were measured in each metastatic LN.

Results

Of the 1,231 fields, 275 (22 %) were positive for metastasis, including 581 LNs from 408 regional LN stations. The sensitivity and specificity of PET/CT examined by each anatomical field were 25.8 and 97.8 %, respectively. The median area of metastatic nests was 17.7 mm² in the PET/CT-N-positive group, and 7.7 mm² in the PET/CT-N-negative group (p < 0.001).

Conclusions

A significant correlation was suggested between the nest size and detection by PET/CT. Because of its low sensitivity, PET/CT alone is insufficient to determine the surgical procedures, especially when considering reduction surgery.     

Role of the standardized uptake value of 18-fluorodeoxyglucose positron emission tomography–computed tomography in detecting the primary tumor and lymph node metastasis in colorectal cancers

Purpose

To assess the role of positron emission tomography–computed tomography (PET–CT) and multidetector-row CT (MD-CT) in detecting the primary lesion and lymph node metastasis in patients with colorectal cancers.

Methods

A collective total of 80 lesions resected from 77 patients were examined pathologically. We analyzed the significance of the standardized uptake value (SUV) and its relationship with the clinicopathologic findings of primary lesions and lymph node metastasis. The detectability of primary lesions and lymph node metastases on PET–CT images was compared with that on MD-CT images.

Results

The detectability of primary lesions was better on PET–CT images than on MD-CT images (p = 0.0023). We observed no significant differences in the SUV with respect to staging, tumor grade, lymphatic or vessel invasion, and macroscopic type; however, primary tumor size analysis revealed that tumors larger than 3 cm had a higher SUV than those smaller than 3 cm. The sensitivity of PET–CT for detecting lymph node metastasis was lower than that of MD-CT, but the specificity of PET–CT was higher than that of MD-CT.

Conclusions

The SUV of primary cancers tends to increase in proportion to tumor size. Although the value of PET–CT in detecting lymph node metastasis is limited, PET -positive lymph nodes can be considered metastatic.     

Relationship Between <Superscript>18</Superscript>F-fluorodeoxyglucose Accumulation and the <Emphasis Type="Italic">BRAF</Emphasis><Superscript>V600E</Superscript> Mutation in Papillary Thyroid Cancer

Background

To determine whether ¹⁸F-fluoro-2-deoxyglucose (¹⁸F-FDG)-PET/CT is useful for predicting the BRAF ^V600E mutation status of a primary papillary thyroid carcinoma (PTC).

Methods

A retrospective analysis was performed in 108 patients who underwent ¹⁸F-FDG positron emission tomography–computed tomography (PET/CT) for staging before thyroidectomy and BRAF analysis in biopsy-confirmed PTC. The maximum standardized uptake value (SUV_max) of the primary tumor was calculated according to FDG accumulation. Univariate and multivariate analyses were performed to assess the association between the SUV_max and clinicopathological variables.

Results

The BRAF ^V600E mutation was detected in 71 of 108 (65.7%) patients. In all subjects, the tumor size and BRAF ^V600E mutation were independently related to the SUV_max according to multivariate analyses (P = 0.002 and 0.007, respectively). The SUV_max was significantly higher in tumors with the BRAF ^V600E mutation than in tumors with wild-type BRAF (10.24 ± 11.89 versus 4.02 ± 3.86; P = 0.007). In the tumor size >1 cm subgroup, the BRAF ^V600E mutation was the only factor significantly associated with the SUV_max (P = 0.016). A SUV_max cutoff level of 4.9 was determined to be significant for predicting the BRAF ^V600E mutation status (sensitivity 77.4%, specificity 100.0%, area under the curve 0.929; P < 0.0001) according to ROC curve analysis.

Conclusions

The BRAF ^V600E mutation is independently associated with high ¹⁸F-FDG uptake in PTC, especially in those with a tumor size >1 cm.

     

Additional surgery for non-curative resection after endoscopic submucosal dissection for gastric cancer: a retrospective analysis of 200 cases

Purpose

Endoscopic submucosal dissection is recommended for early gastric cancer with a low risk of lymph node metastasis. When the pathological findings do not meet the curative criteria; then, an additional gastrectomy with lymph node dissection is recommended. However, most cases have neither lymph node metastasis nor a local residual tumor during an additional surgery.

Methods

This was a single-institutional retrospective cohort study, analyzing 200 patients who underwent an additional gastrectomy after non-curative endoscopic submucosal dissection from January 2005 to October 2015. We reviewed the patients’ clinicopathological data and evaluated the predictors for the presence of a residual tumor.

Results

Histopathology revealed lymph node metastasis in 15 patients (7.5 %) and a local residual tumor in 23 (11.5 %). A multivariable analysis revealed macroscopic findings (flat/elevated type) (p = 0.011, odds ratio = 4.63), lymphatic invasion (p < 0.0001, odds ratio = 14.2), and vascular invasion (p = 0.04, odds ratio = 4.00) to be predictors for lymph node metastasis. A positive vertical margin (p = 0.0027, odds ratio = 3.26) and horizontal margin (p = 0.0008, odds ratio = 5.74) were predictors for a local residual tumor. All cases with lymph node metastasis had lymphovascular invasion with at least one other non-curative factor.

Conclusions

The risk of a residual tumor can, therefore, be estimated based on the histopathology of endoscopic submucosal dissection samples. Lymphovascular invasion appears to be a pivotal predictor of lymph node metastasis.

     

Could 18F-FDG-PET/CT avoid unnecessary thyroidectomies in patients with cytological diagnosis of follicular neoplasm?

Purpose

Preoperative diagnosis of thyroid nodules with “follicular neoplasm” (FN) based on fine-needle aspiration cytology (FNAC) forces thyroidectomy to exclude malignancy. This study explores if ¹⁸F-fluorodeoxyglucose positron emission tomography/computed tomography (¹⁸F-FDG-PET/CT) provides information enough to prevent unnecessary thyroidectomies in this clinical setting.

Methods

This is a prospective study involving 46 consecutive patients scheduled for thyroidectomy due to follicular neoplasm diagnosis in FNAC (36 follicular, 10 Hürthle cell neoplasms, Bethesda classification) since January 2009 until April 2012. All patients underwent preoperative ¹⁸F-FDG-PET/CT. Abnormal ¹⁸F-FDG thyroid uptake was assessed visually and by measuring the maximum standard uptake value (SUVmax). Results were compared with definitive pathology reports.

Results

Thirteen out of 46 patients (28.3 %) were finally diagnosed with thyroid cancer. Focal uptake correlated with a greater risk of malignancy (p?=?0.009). ¹⁸F-FDG-PET/CT focal uptake showed sensitivity, specificity, positive and negative predictive values and overall accuracy of 92.3, 48.5, 41.4, 94.1 and 60.9 %, respectively. The optimal threshold SUVmax to discriminate malignancy was 4.2 with an area under receiver-operating characteristic curve of 0.76 (95 % confidence interval, 0.60–0.90). Use of ¹⁸F-FDG-PET/CT could reduce by 13–25 % the number of thyroidectomies performed for definitive benign nodules. However, it has demonstrated worse predictive ability in the subgroup of patients with diffuse uptake, oncocytic pattern in FNAC and lesions smaller than 2.

Conclusions

¹⁸F-FDG-PET/CT can play a role in the management of thyroid nodules larger than 2 cm cytologically reported as follicular neoplasm without oncocytic differentiation, allowing the avoidance of a significant number of thyroidectomies for definitive benign lesions.     

Scattered Psammomatous Calcifications around Papillary Thyroid Carcinoma

Background

Although psammomatous calcification is a characteristic pathologic feature of papillary thyroid carcinoma (PTC), the clinical meaning of histologically determined scattered psammomatous calcifications around PTC is unknown.

Objective

The aim of this study was to evaluate the clinical significance of scattered psammomatous calcifications around PTC.

Materials and methods

Between January 2009 and July 2009, a total of 546 patients who underwent total thyroidectomy for PTC were enrolled. They were classified into two groups: patients with scattered psammomatous calcifications and patients without psammomatous calcifications. The clinical findings, preoperative diagnostic findings, and histopathologic features were compared between the two groups.

Results

Scattered psammomatous calcifications around PTC were found in 209 patients (38 %), and mostly in younger patients (p = 0.007), those with infiltrative tumor margin (p = 0.022), those with capsule invasion (p = 0.013), and those with lymph node metastasis (p < 0.001). No statistical significance was found in gender, tumor size, multiplicity, and coexisting lymphocytic thyroiditis.

Conclusions

Although further studies with large-scale, long-term follow-up will be necessary to validate the relationship between scattered psammomatous calcifications and prognosis, scattered psammomatous calcification around PTC may have correlations with the aggressiveness of the PTC.     

Clinical Significance of Incidental Colonic 18F-FDG Uptake on PET/CT Images in Patients with Gastric Adenocarcinoma

Background and Objectives

We assessed the ability of positron emission tomography?Ccomputed tomography (PET/CT) to detect synchronous colonic pathology and determined the significance of 18F-fluorodeoxyglucose (¹⁸F-FDG) activity in the colon of gastric cancer patients.

Methods

A total of 239 gastric cancer patients who underwent PET/CT and colonoscopy preoperatively were included. FDG uptake patterns on PET/CT were classified as (1) group A, focal; (2) group B, diffuse; and (3) group C, no uptake. The PET/CT findings were compared with the results of concurrent colonoscopy.

Results

In group A, a total of 123 polyps of >0?mm were observed. Of these, nine polyps were colonic adenocarcinomas and six were high-grade dysplasia. The incidence of colonic adenocarcinomas was significantly higher in group A than in the other two groups (p?=?0.037). There was a significant correlation between SUVmax values and incidence of colonic polyps of >10?mm (r?=?0.471, p?=?0.04). The distribution pattern of SUVmax in polyps with adenoma (>10?mm) was less homogenous than in polyps (>10?mm) with adenocarcinoma.

Conclusions

The focal colonic FDG uptake in PET/CT requires colonoscopic confirmation. The suspicion of colonic malignancy increased in the presence of polyps >10?mm that showed a positive correlation with the SUVmax.     

Papillary Thyroid Carcinoma Located in the Isthmus or Upper Third is Associated with Delphian Lymph Node Metastasis

Background

Delphian lymph node (DLN) metastasis is a recognized indicator of further lymph node involvement in papillary thyroid carcinoma (PTC). The aim of this study was to evaluate the clinicopathological significance of and risk factors for DLN metastasis.

Methods

The medical records of 1,436 patients who underwent primary thyroidectomy for classical PTC with a tumor size of 2 cm or less were reviewed. Of these, 370 patients from whom the DLN was harvested were enrolled. Metastasis in DLN was present in 46 patients and absent in 324 patients. Clinicopathological features were compared according to DLN metastasis.

Results

In univariate analysis, DLN metastasis was associated with suspected lymph node metastasis on preoperative ultrasonography, tumor location in the isthmus or upper third of the thyroid, larger tumor size, extrathyroid extension, lymphovascular invasion, and further lymph node metastasis. Multivariable analysis revealed that DLN metastasis was associated with tumor location in the isthmus or upper third of the thyroid (odds ratio [OR] = 2.420; 95 % confidence interval [CI] 1.193–4.910) and further lymph node metastasis (OR = 4.746; 95 % CI 2.065–10.908).

Conclusions

DLN metastasis in PTC is associated with tumor location in the isthmus or upper third of the thyroid and unfavorable clinicopathological characteristics. Careful consideration and patient management are warranted when preoperative ultrasonography indicates that the tumor is located in the isthmus or upper third of the thyroid.     

Incidental Thyroid Carcinoma by FDG-PET/CT: A Study of Clinicopathological Characteristics

Background

The rising incidence of incidental thyroid carcinoma (ITC) detected during fluoro-2-deoxy-d-glucose (FDG)-positron emission tomography (PET)/computed tomography (CT) scanning poses a challenge to clinicians. The present study aims to critically evaluate the clinicopathological characteristics of ITC detected by FDG-PET/CT.

Methods

Among the 557 patients managed at our institution, 40 (7.2%) patients were identified as having ITC. Of these, 22 patients had their tumor detected by FDG-PET/CT (PET group) and 11 by ultrasonography (USG group). Additional bedside ultrasonography ± fine-needle aspiration (FNA) was done in all patients at their clinic visit. The clinicopathological characteristics were compared between the PET and USG groups.

Results

The PET group had significantly more patients with history of nonthyroidal malignancy (P < 0.001). Papillary carcinoma was the most common histological type in both groups. Despite having similar histological and prognostic features including tumor size, tumor multifocality, capsular invasion, extrathyroidal extension, and lymph node metastases, tumor bilaterality (or presence of contralateral tumor focus) was significantly more frequent in the PET than the USG group (P = 0.04). The tumors were also more advanced by the tumor–node–metastasis (TNM) staging system in the PET group (P = 0.021). None of the contralateral tumor foci were evident preoperatively. One patient in the USG group developed metastatic thyroid carcinoma in neck lymph nodes 28 months after thyroid resection.

Conclusion

ITC by FDG-PET/CT had higher incidence of tumor bilaterality than those detected by ultrasonography. Total thyroidectomy should be considered for ITC detected by FDG-PET/CT even for tumor size <10 mm.     

Prognosis After Sublobar Resection of Small-sized Non-small Cell Lung Cancer with Visceral Pleural or Lymphovascular Invasion

Background

Although standard surgical treatment of stage I non-small cell lung cancer (NSCLC) is lobectomy, sublobar resection may be elected for small-sized (≤2 cm) peripheral tumors. Our aim was examine the need for completion lobectomy in the event of confirmed pleural or lymphovascular invasion after sublobar resection of NSCLC.

Methods

A total of 271 consecutive patients undergoing curative resection of stage I NSCLC ≤2 cm were reviewed retrospectively, analyzing clinicopathologic findings and survival times of those with invasion-positive (visceral pleural or lymphovascular invasion) or invasion-negative (neither visceral pleural nor lymphovascular invasion) tumors by surgical approach (sublobar resection vs lobectomy).

Results

Aside from age and pulmonary function, clinicopathologic characteristics of the patient subsets did not differ significantly, nor did 5-year recurrence-free survival rates of surgical subsets (sublobar resection vs lobectomy) in respective tumor groups (invasion-positive 78.9 vs 79.8%, p = 0.928; invasion-negative 80.2 vs 85.4%, p = 0.505). In multivariate analysis, dissected lymph node count was the sole parameter significantly impacting recurrence of stage I invasion-positive NSCLC (hazard ratio = 0.914, 95% confidence interval 0.845–0.988; p = 0.023). Sublobar resection was not a risk factor for recurrence.

Conclusions

Survival rates for patients with small-sized (≤2 cm) NSCLC and visceral pleural or lymphovascular invasion did not differ significantly, whether sublobar resection or lobectomy was done. Hence, completion lobectomy is unnecessary in this setting.