Restaging rectal cancer following neoadjuvant chemoradiotherapy

Correct tumour restaging is pivotal for identifying the most personalised surgical treatment for patients with locally advanced rectal cancer undergoing neoadjuvant therapy, and works to avoid both poor oncological outcome and overtreatment. Digital rectal examination, endoscopy, and pelvic magnetic resonance imaging are the recommended modalities for local tumour restaging, while chest and abdominal computed tomography are utilised for the assessment of distant disease. The optimal length of time between neoadjuvant treatment and restaging, in terms of both oncological safety and clinical effectiveness of treatment, remains unclear, especially for patients receiving prolonged total neoadjuvant therapy. The timely identification of patients who are radioresistant and at risk of disease progression remains challenging.

PSMA PET/CT: joint EANM procedure guideline/SNMMI procedure standard for prostate cancer imaging 2.0

Here we aim to provide updated guidance and standards for the indication, acquisition, and interpretation of PSMA PET/CT for prostate cancer imaging. Procedures and characteristics are reported for a variety of available PSMA small radioligands. Different scenarios for the clinical use of PSMA-ligand PET/CT are discussed. This document provides clinicians and technicians with the best available evidence, to support the implementation of PSMA PET/CT imaging in research and routine practice.

Correlation between PET-CT and ct in the staging after the treatment of head and neck squamous cell carcinoma

OBJECTIVE

The aim of this study is to find out if a single imaging test is enough to follow-up on an oncological post-treatment patient. In such a case, we would know which was more valuable after comparing the two, by CT or PET-CT.

METHODS

Between January 2012 and July 2018, we collected data from all patients with previous medical history who were treated with a head and neck squamous cell carcinoma in our hospital, through surgery or by using an organ preservation protocol which we had done. Patients were required to have a CT and a PET-CT performed in a maximum period of 30 days between techniques. We compared the post post-treatment stage given to each case by using only the physical examination (only the CT and the PET-CT), with the ones given by the Tumor Board. After treatment, we analysed the similarity through Cramer's V statistic test.

RESULTS

We performed a comparative analysis, obtaining a correlation of 0.426 between the stages given by the Tumor Board and the one assigned based on physical examination, without imaging techniques. By only using the computed tomography as an imaging method the correlation was 0.565, whereas with only the use of positron emission computed technology, it was estimated at 0.858. When we compared the statistical association between stages using exclusively one of the two imaging techniques, the correlation was 0.451.

CONCLUSION

Independent of the modality, we have demonstrated that in patients who have received previous treatment, there was a higher correlation in the stages with respect to the diagnostic method conducted by the Tumor Board using PET-CT as the sole image.

LEVEL OF EVIDENCE

Level 1.

Establishment and validation of nomograms for predicting mesorectal lymph node staging and restaging

BACKGROUND

Preoperative determination of lymph node (LN) status is crucial in treatment planning for rectal cancer. This study prospectively evaluated the risk factors for lymph node metastasis (LNM) at staging and restaging based on a node-by-node pairing between MRI imaging findings and histopathology and constructed nomograms to evaluate its diagnostic value.

METHODS

From July 2021 to July 2022, patients with histopathologically verified rectal cancer who underwent MRI before surgery were prospectively enrolled. Histological examination of each LN status in the surgical specimens and anatomical matching with preoperative imaging. Taking histopathological results as the gold standard, federating clinical features from patients and LN imaging features on MRI-T2WI. Risk factors for LN metastasis were identified by multivariate logistic regression analysis and used to create a nomogram. The performance of the nomograms was assessed with calibration plots and bootstrapped-concordance index and validated using validation cohorts.

RESULTS

A total of 500 target LNs in 120 patients were successfully matched with node-by-node comparisons. A total of 353 LNs did not receive neoadjuvant therapy and 147 LNs received neoadjuvant chemoradiotherapy (neoCRT). Characterization of LNs not receiving neoadjuvant therapy and multivariate regression showed that the short diameter, preoperative CEA level, mrT-stage, border contour, and signal intensity were associated with a high risk of LN metastasis (P < 0.05). The nomogram predicted that the area under the curve was 0.855 (95% CI, 0.794-0.916) and 0.854 (95% CI, 0.727-0.980) in the training and validation cohorts, respectively. In the neoadjuvant therapy group, short diameter, ymrT-stage, internal signal, and MRI-EMVI were associated with LN positivity (P < 0.05), and the area under the curves using the nomogram was 0.912 (95% CI, 0.856-0.968) and 0.915 (95% CI, 0.817-1.000) in two cohorts. The calibration curves demonstrate good agreement between the predicted and actual probabilities for both the training and validation cohorts.

CONCLUSION

Our nomograms combined with preoperative clinical and imaging biomarkers have the potential to improve the prediction of nodal involvement, which can be used as an essential reference for preoperative N staging and restaging of rectal cancer.

Clinical and prognostic 18F-FDG PET/CT role in recurrent vulvar cancer: a multicentric experience

PURPOSE

The aim of this retrospective multicentric study was to investigate the diagnostic performance, the prognostic value and the impact of ¹⁸F-FDG PET/CT on treatment decision-making in patients with suspected recurrent vulvar cancer (VC).

MATERIALS AND METHODS

Sixty-three patients affected by VC performed ¹⁸F-FDG-PET/CT for restaging purposes in case of suspected clinical and/or radiological recurrence. Histopatology results if available and/or clinical-imaging follow-up for at least 12 months were considered as reference standard. The diagnostic accuracy and the clinical impact of ¹⁸F-FDG PET/CT were investigated. Progression free survival (PFS) and overall survival (OS) were calculated using Kaplan-Meier curves.

RESULTS

Fifty-two (82.5%) PET/CT showed the presence of recurrence, while the remaining 11 (17.5%) were negative. Sensitivity, specificity, positive predictive value, negative predictive value and accuracy of PET/CT were 100% (95%CI 93-100%), 92% (95%CI 62-100%), 98% (95%CI 89-99%), 100% and 98% (95%CI 92-100%). A relevant impact of ¹⁸F-FDG PET/CT imaging was registered in 28 cases: in 12 cases moving from local therapy to chemotherapy due to the recognition of disseminate localizations; in 10 showing the site of recurrence in presence of negative conventional imaging, and in 6 cases confirming to be true negative and avoiding unnecessary therapies. Beside advanced age and HPV status, a positive restaging ¹⁸F-FDG PET/CT scan was significantly correlated with shorter PFS and OS compared to negative scan (p < 0.001).

CONCLUSIONS

¹⁸F-FDG PET/CT demonstrated to be an accurate tool in the assessing of recurrent VC with high sensitivity and specificity and with a significant impact on clinical decision-making. Restaging ¹⁸F-FDG PET/CT findings were associated with survival.

Reconsidering the American Joint Committee on Cancer Eighth Edition TNM Staging Manual Classifications for T2b and T3 NSCLC

INTRODUCTION

The American Joint Committee on Cancer (AJCC) eighth edition TNM staging manual for NSCLC, derived from the International Association for the Study of Lung Cancer (IASLC) Staging Project, designates tumors with additional nodule(s) in the same lobe as T3. This study sought to externally validate the results of the IASLC, which showed a trend in improved survival for such tumors, but excluded treatment-based adjustment, by assessing whether these tumors have worse survival than T2b NSCLC.

METHODS

Overall survival of patients with T2b-T3, N0-3, M0 NSCLC (satisfying a single T descriptor of tumors >4 cm but ≤5 cm in greatest dimension ["T2b"], tumors >5 cm but ≤7 cm in greatest dimension ["T3-Size"], or tumors with additional nodule(s) in the same lobe ["T3-Add"]), according to the AJCC eighth edition, in the National Cancer Database (2010-2015), was evaluated using multivariable Cox proportional hazards modeling and propensity score matching.

RESULTS

31,563 patients with T2b-T3, N0-3, M0 NSCLC met the study inclusion criteria. In multivariable-adjusted analysis, T3-Add tumors had improved overall survival compared with T3-Size tumors (Hazard Ratio = 0.86, 95% Confidence Interval: 0.82-0.89, p < 0.001) and similar survival compared with T2b tumors (Hazard Ratio = 1.04, 95% Confidence Interval: 0.97-1.12, p = 0.28). A propensity score-matched analysis of 2260 T3-Add and 2,260 T2b patients, well-balanced on 16 common prognostic covariates, including treatment type (surgery, chemotherapy, or radiation), revealed similar 5-year survival (53.4% versus 52.3%, p = 0.30).

CONCLUSIONS

In this national analysis, T3-Add tumors had better survival than other T3 tumors and similar survival to T2b tumors. These findings may be taken into consideration for the AJCC ninth edition staging classifications.

Rectal MRI after neoadjuvant chemoradiation therapy: a pictorial guide to interpretation

Magnetic resonance imaging (MRI) is the current reference standard imaging modality for restaging rectal cancer after neoadjuvant chemoradiation and is used to guide clinical management decisions. This pictorial essay provides an illustrative atlas of the key MRI features used to assess rectal cancer after treatment. MRI findings of residual tumor including non-mucinous, mucinous, and signet-ring cell adenocarcinoma subtypes are correlated with histopathology. Imaging appearances of treatment changes that mimic residual tumor in the setting of confirmed pathological complete response at resection are illustrated. Treatment complications are also shown. Knowledge of these imaging findings and their importance may help radiologists comply with all elements of the structured reporting templates proposed by the Rectal Cancer Disease Focused Panel of the Society of Abdominal Radiology and by the European Society of Gastrointestinal and Abdominal Radiology.

Focal unspecific bone uptake on [18F]-PSMA-1007 PET: a multicenter retrospective evaluation of the distribution, frequency, and quantitative parameters of a potential pitfall in prostate cancer imaging

Purpose

Improved logistics and availability led to a rapid increase in the use of [¹⁸F]-PSMA-1007 for prostate cancer PET imaging. Initial data suggests increased uptake in benign lesions compared to [⁶⁸ Ga]-PSMA-11, and clinical observations found increased unspecific bone uptake (UBU). We therefore investigate the frequency and characteristics of UBU in [¹⁸F]-PSMA-1007 PET.

Methods

We retrospectively analyzed [¹⁸F]-PSMA-1007 PET scans from four centers for the presence of UBU, defined as a focal mild-to-moderate uptake (SUV_max < 10.0) not obviously related to a benign or malignant cause. If present, up to three leading UBUs were quantified (SUV_max), localized, and correlated to clinical parameters, such as age, PSA, injected dose, Gleason score, tumor size (T1–T4), and type of PET scanner (analog vs. digital). Additionally, clinical and imaging follow-up results and therapeutic impact were evaluated.

Results

UBUs were identified in 179 out of 348 patients (51.4%). The most frequent localizations were ribs (57.5%) and pelvis (24.8%). The frequency of UBUs was not associated with PSA, Gleason score, tumor size, age, or the injected [¹⁸F]-PSMA-1007 dose. UBUs were significantly more frequent in images obtained with digital PET/CT scans (n = 74, 82%) than analog PET/CT scans (n = 221, 40.3%) (p = .0001) but not in digital PET/MR (n = 53, 51%) (p = .1599). In 80 out of 179 patients (44.7%), the interpretation of UBUs was critical for therapeutic management and therefore considered clinically relevant. For 65 UBUs, follow-ups were available: three biopsies, three radiotherapies with PSA follow-up, and 59 cases with imaging. After follow-up, UBUs were still considered unclear in 28 of 65 patients (43%), benign in 28 (43%), and malignant in nine (14%) patients.

Conclusion

UBUs occur in two-thirds of patients imaged with [¹⁸F]-PSMA-1007 PET/CT and are significantly more frequent on digital PET scanners than analog scanners. UBUs should be interpreted carefully to avoid over-staging.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00259-021-05424-x.

PET/MRI: The future of cancer restaging

The re-staging of cancer is one of the main oncological problems faced in the present day. Restaging can lead to the emergence of surgical therapy alternatives for a down-staged cancer, or to the consideration of secondary or tertiary chemotherapies for an up-staged cancer. That said, with the application of one of the surgical, radiotheraphy(RT) or chemotherapy(CT) protocols, complications may occur, and restaging becomes difficult. Another difficulty may be encountered in explaining to the patient that additional therapy protocols may be needed after an accurate restaging. After surgery, RT or CT, renal, hepatic and bone marrow reserves may severely be decreased, and since the primary therapy protocol may reduce significantly the patient's performance status, "accurate restaging" is the most important problem to be resolved when planning further therapy.

Limited Role for Routine Restaging After Neoadjuvant Therapy in Locally Advanced Rectal Cancer

BACKGROUND

Although many patients with locally advanced rectal cancer undergo restaging imaging after neoadjuvant chemoradiotherapy and before surgery, the benefit of this practice is unclear. The purpose of this study was to examine the impact of reimaging on outcomes.

MATERIALS AND METHODS

We performed a retrospective analysis of consecutive patients with stage 2 and 3 rectal adenocarcinoma treated with neoadjuvant chemoradiotherapy between May 2005 and April 2018. Patient and disease characteristics, imaging, treatment, and oncologic outcomes were compared between those who underwent restaging and those who went directly to surgery. Predictors of outcomes and cost effectiveness of restaging were determined.

RESULTS

Of 224 patients, 146 underwent restaging. Six restaged patients had findings leading to a change in management. There was no difference in freedom from recurrence (P = 0.807) and overall survival (P = 0.684) based on restaging. Pretreatment carcinoembryonic antigen level >3 ng/mL (P = 0.010), clinical T stage 4 (P = 0.016), and pathologic T4 (P = 0.047) and N2 (P = 0.002) disease increased the risk of death, whereas adjuvant chemotherapy decreased the risk of death (P < 0.001) on multivariate analysis. Disease recurrence was lower with pelvic exenteration (P = 0.005) and in females (P = 0.039) and higher with pathologic N2 (P = 0.003) and N3 (P = 0.002) disease. The average cost of reimaging is $40,309 per change in management; however, $45 is saved per patient when downstream surgical costs are considered.

CONCLUSIONS

Imaging restaging after neoadjuvant chemoradiotherapy in patients with locally advanced rectal cancer rarely changes treatment and does not improve survival. In a subset of patients at higher risk for worse outcome, reimaging may be beneficial.

The additive value of restaging-CT during neoadjuvant chemotherapy for gastric cancer

INTRODUCTION

Computed tomography (CT) is used for restaging of gastric cancer patients during neoadjuvant chemotherapy (NAC). The treatment strategy could be altered after detection of distant interval metastases, possibly leading to a reduction in unnecessary chemotherapy cycles, its related toxicity, and surgical procedures. The aim of this study was to evaluate the additive value of restaging-CT during NAC in guiding clinical decision making in gastric cancer.

MATERIALS AND METHODS

This retrospective, multicenter cohort study identified all patients with surgically resectable gastric adenocarcinoma (cT1-4a-x, N0-3-x, M0-x), who started NAC with curative intent. Restaging-CT was performed after 2 out of 3 cycles of NAC. The primary outcome was treatment alterations made based on restaging-CT by a multidisciplinary tumor board. Confirmation of metastases was obtained by surgery or biopsy.

RESULTS

Between 2007 and 2015, CT-restaging was performed in 122 out of 152 included patients and timed after 2 cycles (n = 76) or after 3 cycles (n = 46) of NAC. Restaging-CT revealed a metastasis in 1 out of 122 restaged patients (1%) after which surgical resection was omitted, whereas 4 patients (3%) with distant interval metastases were not identified by restaging-CT and underwent a futile laparotomy. In 5 out of 76 patients (7%) disease progression was detected while undergoing NAC, leading to omission of the 3rd cycle of chemotherapy.

CONCLUSION

The additive value of restaging-CT during NAC in gastric cancer is limited in guiding clinical decision making and therefore not recommended. Further studies may identify subgroups that may benefit of alternative diagnostic modalities.

MRI response rate after short-course radiotherapy on rectal cancer in the elderly comorbid patient: results from a retrospective cohort study

Background

The aim of the present study was to evaluate MRI response rate and clinical outcome of short-course radiotherapy (SCRT) on rectal cancer as an alternative to chemoradiotherapy in patients where downstaging is indicated.

Methods

A retrospective analysis was performed of a patient cohort with rectal carcinoma (cT1-4cN0-2 cM0–1) from a large teaching hospital receiving restaging MRI, deferred surgery or no surgery after SCRT between 2011 and 2017. Patients who received chemotherapy during the interval between SCRT and restaging MRI were excluded.

The primary outcome measure was the magnetic resonance tumor regression grade (mrTRG) at restaging MRI after SCRT followed by a long interval. Secondary, pathological tumor stage, complete resection rate and 1-year overall survival were assessed.

Results

A total of 47 patients (M:F = 27:20, median age 80 (range 53–88) years), were included. In 33 patients MRI was performed for response assessment 10 weeks after SCRT. A moderate or good response (mrTRG≤3) was observed in 24 of 33 patients (73%). While most patients (85%; n = 28) showed cT3 or cT4 stage on baseline MRI, a ypT3 or ypT4 stage was found in only 20 patients (61%) after SCRT (p <  0.01). A complete radiologic response (mrTRG 1) was seen in 4 patients (12%). Clinical N+ stage was diagnosed in n = 23 (70%) before SCRT compared to n = 8 (30%) post-treatment (p = 0.03).

After SCRT, 39 patients underwent deferred surgery (after a median of 14 weeks after start of SCRT) and a resection with complete margins was achieved in 35 (90%) patients. One-year overall survival after surgery was 82%. Complete pathological response was found in 2 patients (5%).

Conclusions

The use of SCRT followed by a long interval to restaging showed a moderate to good response in 73% and therefore can be considered as an alternative to chemoradiotherapy in elderly comorbid patients.

Role of 18F-FDG PET/CT in restaging and follow-up of patients with GIST

PURPOSE

Gastrointestinal stromal tumor (GIST) is a rare tumor with high risk of recurrence and poor prognosis in case of advanced GIST. The aim of this study was to evaluate the possible role of 18F-FDG PET/CT in restaging GIST.

METHODS

Fifty-four patients (30 male) with histological proven GIST underwent 100 18F-FDG PET/CT for restaging in suspected recurrence or during follow-up. Histopathology results and/or clinical/imaging follow-up for at least 12 months were considered as reference standard. Moreover, the diagnostic accuracy and clinical impact of 18F-FDG PET/CT were calculated.

RESULTS

Twenty-seven (27%) 18F-FDG PET/CT were positive, while the remaining 73 (73%) were negative. Sensitivity, specificity, PPV, NPV, and accuracy of PET/CT were 89% (95% CI 72-98%), 97% (95% CI 90-100%), 93% (95% CI 76-98%), 96% (95% CI 89-98%), and 95% (95% CI 89-98%). 18F-FDG PET/CT had a positive clinical impact in 18/100 studies changing the management, in 8 cases switching from local therapy to systemic therapy due to the detection of disseminate disease at PET/CT, in three cases recognizing relapse not detected by conventional imaging, and in 7 cases demonstrating to be true negative and avoiding unnecessary therapies.

CONCLUSIONS

18F-FDG PET/CT seems to be an accurate method for detection and localization of local and distant recurrence in GIST with good sensitivity and specificity and significant impact on clinical decision-making.

Current controversy, confusion, and imprecision in the use and interpretation of rectal MRI

There has been a rapid increase in the utilization of MRI in rectal cancer staging in the USA essentially replacing endorectal ultrasound and mimicking the trend in Europe seen in the 1990s and 2000s. Accompanying this trend, there is a demand, and recognized need, for greater precision and clarification of confusing, misunderstood and poorly understood concepts, facts, statements and nomenclature regarding rectal cancer and the use of pelvic MRI for diagnosis. As such, this Review, part evidence-based and part expert opinion, will attempt to elucidate and clarify several concepts the authors have encountered in 25 years of imaging rectal cancer, focusing on MRI.

Current controversy, confusion, and imprecision in the use and interpretation of rectal MRI

There has been a rapid increase in the utilization of MRI in rectal cancer staging in the USA essentially replacing endorectal ultrasound and mimicking the trend in Europe seen in the 1990s and 2000s. Accompanying this trend, there is a demand, and recognized need, for greater precision and clarification of confusing, misunderstood and poorly understood concepts, facts, statements and nomenclature regarding rectal cancer and the use of pelvic MRI for diagnosis. As such, this Review, part evidence-based and part expert opinion, will attempt to elucidate and clarify several concepts the authors have encountered in 25 years of imaging rectal cancer, focusing on MRI.

Role of Positron Emission Tomography Imaging in Metabolically Active Renal Cell Carcinoma

PURPOSE OF REVIEW

The clinical role of fluorine-18 fluoro-2-deoxyglucose (FDG)-positron emission tomography (PET) in renal cell carcinoma (RCC) is still evolving. Use of FDG PET in RCC is currently not a standard investigation in the diagnosis and staging of RCC due to its renal excretion. This review focuses on the clinical role and current status of FDG PET and PET/CT in RCC.

RECENT FINDINGS

Studies investigating the role of FDG PET in localized RCC were largely disappointing. Several studies have demonstrated that the use of hybrid imaging PET/CT is feasible in evaluating the extra-renal disease. A current review of the literature determines PET/CT to be a valuable tool both in treatment decision-making and monitoring and in predicting the survival in recurrent and metastatic RCC. PET/CT might be a viable option in the evaluation of RCC, especially recurrent and metastatic disease. PET/CT has also shown to play a role in predicting survival and monitoring therapy response.

Detecting Pathological Complete Response in Esophageal Cancer after Neoadjuvant Therapy Based on Imaging Techniques: A Diagnostic Systematic Review and Meta-Analysis

INTRODUCTION

Up to 32% of patients with esophageal cancer show a pathological complete response (ypCR) after neoadjuvant therapy. To prevent overtreatment, the indication to perform esophagectomy in these patients should be reconsidered. Implementing an organ-preserving strategy for patients with ypCR requires an accurate assessment of residual disease after neoadjuvant treatment. The aim of this study was to systematically review the effectiveness of imaging techniques used for detection of ypCR after neoadjuvant therapy but before resection in patients with esophageal cancer.

METHODS

A systematic literature search of the Medline, Embase, and Cochrane Library databases was performed from January 1, 2000, to December 13, 2017. Eligible studies were diagnostic studies that compared results of imaging modalities after neoadjuvant therapy to histopathological findings in the resection specimen after esophagectomy. Methodological quality was assessed by the Cochrane Quality Assessment of Diagnostic Accuracy Studies, version 2, model. Primary outcome measures were true positive, false-positive, false-negative, and true negative values of imaging techniques predicting ypCR. A meta-analysis was performed by pooling sensitivities and specificities by using a bivariate model.

RESULTS

A total of 4420 articles were identified. After exclusion of irrelevant titles and abstracts, 360 articles were reviewed in full text. In total, four imaging modalities (computed tomography [CT], positron emission tomography [PET-CT], endoscopic ultrasound [EUS], and magnetic resonance imaging [MRI]) were used for restaging. The meta-analysis was conducted with data from 56 studies involving 3625 patients. The pooled sensitivities of CT, PET-CT, EUS, and MRI for detecting ypCR were 0.35, 0.62, 0.01 and 0.80, respectively, whereas the pooled specificities were 0.83, 0.73, 0.99, and 0.83, respectively. The positive predictive value in detecting ypCR was 0.47 for CT, 0.41 for PET-CT, not applicable for EUS, and 0.61 for MRI.

CONCLUSION

Current imaging modalities such as CT, PET-CT, and EUS seem to be insufficiently accurate to identify complete responders. More accurate diagnostic tests are needed to improve restaging accuracy for patients with esophageal cancer.

Role of 18F-FDG PET/CT in establishing new clinical and therapeutic modalities in lung cancer. A short review

Lung cancer is a fairly common malignancy. An early diagnosis and a reliable staging and re-staging with the aim to detect both local and distant relapse are of utmost importance in planning the therapeutic management. The imaging diagnostic work-up of patients with lung cancer usually includes conventional imaging (chest X-ray, contrast-enhanced CT, bone scan) and more recently ¹⁸F-FDG PET/CT. Great advances in the management of lung cancer are based on the information provided by ¹⁸F-FDG PET/CT, as it supplies both metabolic and anatomic information (better localisation). There is vast evidence in the literature demonstrating its utility in (a) characterising benign versus malignant solitary nodules, (b) staging and re-staging lung cancer, (c) guiding the type of therapy, (d) monitoring treatment response and (e) predicting outcome. In particular, given its specificity in differentiating ¹⁸F-FDG-avid relapse from post-surgical changes or post-radiation fibrosis (which do not take up ¹⁸F-FDG), PET/CT can detect recurrent disease after initial treatment and (being a whole-body technique) has demonstrated high accuracy in the detection of distant metastases or secondary tumours. In conclusion, ¹⁸F-FDG PET/CT can be considered a highly accurate and reliable method for staging and re-staging lung cancer, and is highly effective in guiding personalised therapies.

Clinical utility of 68Ga-DOTATOC positron emission tomography/computed tomography for recurrent renal cell carcinoma

PURPOSE

Positron emission tomography (PET)/computed tomography (CT) with ⁶⁸Ga-labelled 1,4,7,10-tetraazacyclododecane-N,N',N″,N″'-tetraacetic acid-D-Phe¹-Tyr³-octreotide (DOTATOC) has been accepted as a diagnostic imaging tool especially for patients with neuroendocrine tumours. However, its clinical usefulness for restaging of renal cell carcinoma (RCC) has not been fully investigated. This retrospective study was performed to elucidate the clinical value of PET/CT using ⁶⁸Ga-DOTATOC in patients with known or suspected recurrent RCC.

METHODS

We analysed 25 consecutive patients who underwent DOTATOC-PET/CT scans after surgery for RCC (23 clear cell, 1 papillary, 1 unclassified). PET/CT findings were reviewed and the detection rate was calculated on a patient and lesion basis. The detectability was compared in patients who also underwent PET/CT scans with ¹⁸F-fluorodeoxyglucose (FDG). Histopathological findings or clinical follow-up were used as the reference standard.

RESULTS

Based on the final diagnosis, 76 recurrent or metastatic lesions were confirmed in this population. Of these lesions, 66 lesions in 22 patients were positive by DOTATOC-PET/CT. The patient-based and lesion-based sensitivity was 88% (22/25) and 87% (66/76), respectively. Twelve patients underwent both DOTATOC-PET/CT and FDG-PET/CT. The lesion-based sensitivity of DOTATOC was 74% (20/27), while that of FDG was 59% (16/27). Eight lesions were identified only by DOTATOC, but four lesions from papillary RCC were detected only by FDG.

CONCLUSION

Our data indicate that DOTATOC-PET/CT would be useful for detecting recurrent foci in patients with clear cell RCC. DOTATOC-PET/CT and FDG-PET/CT are considered to have complementary roles.

Utility of a repeat PET/CT scan in HPV-associated Oropharyngeal Cancer following incomplete nodal response from (chemo)radiotherapy

OBJECTIVES

To assess the utility of a repeat positron emission tomography/computed tomography (PET/CT) instead of immediate neck dissection (ND) for incomplete nodal response (IR) in Human Papillomavirus (HPV)-associated oropharyngeal squamous cell carcinoma (OPC) following chemoradiotherapy/radiotherapy [(chemo)RT].

MATERIALS AND METHODS

Patients with non-distant metastatic, node positive (N+) disease treated between Jan/2005 to Jan/2016, achieved complete response at the primary with no distant relapse on a 12-week re-staging PET/CT were evaluated. Patients underwent surveillance after complete nodal response (CR). Patients with IR underwent repeat PET/CT at 16 weeks to direct neck management. Primary endpoints were CR conversion rate and subsequent regional failure following a 16-week PET/CT directed ND. Secondary endpoints were predictive values (PV) of the 12- and 16-week PET/CT for residual nodal disease, predictors for requiring the 16-week PET/CT, 5 year regional, locoregional failure free survival (FFS) and overall survival (OS).

RESULTS

235 patients were evaluated. Median follow up was 56 (range 19-60) months. 41 patients underwent 16-week re-staging PET/CT, 29 (71%) converted to CR. No subsequent regional failures occurred following a 16-week PET/CT directed ND. Positive and negative PV of the 12- and 16-week PET/CT for residual nodal disease was 12% & 98%, and 33% & 97%, respectively. N-category (AJCC/UICC 7th edition) predicted for requiring a 16-week PET/CT on univariate analysis (P-value 0.02). 5 year regional, locoregional FFS and OS was 95.8%, 93.4% and 90.8%, respectively.

CONCLUSION

For N+ HPV-associated OPC achieving IR on the 12-week re-staging PET/CT following (chemo)RT, a repeat 16-week PET/CT can spare patients from unnecessary surgery.

Role of 18F-FDG PET/CT in restaging and follow-up of patients with uterine sarcomas

PURPOSE

Uterine sarcomas are rare tumors with poor prognosis due to the high recurrence rates. The current role of ¹⁸F-FDG PET/CT in the post-therapy surveillance is not established yet.

MATERIALS AND METHODS

Forty-one women with uterine sarcoma underwent 73 ¹⁸F-FDG PET/CT for restaging in suspected recurrence or during follow-up in asymptomatic patients. Histopathology results and/or clinical/imaging follow-up for at least 12 months were considered the reference standard. The diagnostic accuracy and clinical impact of ¹⁸F-FDG PET/CT was calculated.

RESULTS

Thirty-three ¹⁸F-FDG PET/CT were positive, while the remaining 40 studies were negative. The overall sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and accuracy of ¹⁸F-FDG PET/CT were 88%, 98%, 97%, 91% and 93%, respectively. Considering patients with clinical or radiological suspicion of recurrence (n=47) and those during follow-up (n=26), sensitivity, specificity, PPV, NPV and accuracy of ¹⁸F-FDG PET/CT were 89%, 100%, 100%, 86% and 94%, and 80%, 95%, 80%, 95% and 92%, respectively. ¹⁸F-FDG PET/CT had a positive clinical impact in 9/73 (12%) studies and changed the clinical management in 8/41 (20%) patients.

CONCLUSIONS

¹⁸F-FDG PET/CT seems to be an accurate method for detection and localization of local and distant recurrence in patients with uterine sarcoma with good sensitivity and specificity and significant impact on clinical decision making.

Comparison of [68Ga]Ga-PSMA-11 PET/CT with [18F]NaF PET/CT in the evaluation of bone metastases in metastatic prostate cancer patients prior to radionuclide therapy

AIM

The purpose of this study was to investigate the diagnostic performance of ⁶⁸Ga-PSMA-11 PET/CT in the evaluation of bone metastases in metastatic prostate cancer (PC) patients scheduled for radionuclide therapy in comparison to [¹⁸F]sodium fluoride (¹⁸F-NaF) PET/CT.

METHODS

Sixteen metastatic PC patients with known skeletal metastases, who underwent both ⁶⁸Ga-PSMA-11 PET/CT and ¹⁸F-NaF PET/CT for assessment of metastatic burden prior to radionuclide therapy, were analysed retrospectively. The performance of both tracers was calculated on a lesion-based comparison. Intensity of tracer accumulation of pathologic bone lesions on ¹⁸F-NaF PET and ⁶⁸Ga-PSMA-11 PET was measured with maximum standardized uptake values (SUV_max) and compared to background activity of normal bone. In addition, SUV_max values of PET-positive bone lesions were analysed with respect to morphologic characteristics on CT. Bone metastases were either confirmed by CT or follow-up PET scan.

RESULTS

In contrast to 468 PET-positive lesions suggestive of bone metastases on ¹⁸F-NaF PET, only 351 of the lesions were also judged positive on ⁶⁸Ga-PSMA-11 PET (75.0%). Intensity of tracer accumulation of pathologic skeletal lesions was significantly higher on ¹⁸F-NaF PET compared to ⁶⁸Ga-PSMA-11 PET, showing a median SUV_max of 27.0 and 6.0, respectively (p < 0.001). Background activity of normal bone was lower on ⁶⁸Ga-PSMA-11 PET, with a median SUV_max of 1.0 in comparison to 2.7 on ¹⁸F-NaF PET; however, tumour to background ratio was significantly higher on ¹⁸F-NaF PET (9.8 versus 5.9 on ⁶⁸Ga-PSMA-11 PET; p = 0.042). Based on morphologic lesion characterisation on CT, ¹⁸F-NaF PET revealed median SUV_max values of 23.6 for osteosclerotic, 35.0 for osteolytic, and 19.0 for lesions not visible on CT, whereas on ⁶⁸Ga-PSMA-11 PET median SUV_max values of 5.0 in osteosclerotic, 29.5 in osteolytic, and 7.5 in lesions not seen on CT were measured. Intensity of tracer accumulation between¹⁸F-NaF PET and ⁶⁸Ga-PSMA-11 PET was significantly higher in osteosclerotic (p < 0.001) and lesions not visible on CT (p = 0.012).

CONCLUSION

In comparison to ⁶⁸Ga-PSMA-11 PET/CT, ¹⁸F-NaF PET/CT detects a higher number of pathologic bone lesions in advanced stage PC patients scheduled for radionuclide therapy. Our data suggest that ⁶⁸Ga-PSMA-11 PET should be combined with ¹⁸F-NaF PET in PC patients with skeletal metastases for restaging prior to initiation or modification of therapy.

Increased evidence for the prognostic value of FDG uptake on late-treatment PET in non-tumour-affected oesophagus in irradiated patients with oesophageal carcinoma

PURPOSE

¹⁸F-FDG uptake in irradiated non-tumour-affected oesophagus (NTO) on restaging PET is a potential surrogate for the measurement of radiation-induced inflammation. Radiation-induced inflammation itself has been shown to be of high prognostic relevance in patients undergoing preoperative radiochemotherapy (RCT) for locally advanced oesophageal cancer. We assessed the prognostic relevance of FDG uptake in the NTO in an independent cohort of patients treated with definitive RCT.

METHODS

This retrospective evaluation included 72 patients with oesophageal squamous cell carcinoma treated with definitive RCT with curative intent. All patients underwent pretreatment and restaging FDG PET after receiving a radiation dose of 40-50 Gy. Standardized uptake values (SUV_max/SUV_mean), metabolic tumour volume (MTV) and relative changes from pretreatment to restaging PET (∆SUV_max/∆SUV_mean) were determined within the tumour and NTO. Univariate Cox regression with respect to overall survival (OS), local control (LC), distant metastases (DM) and treatment failure (TF) was performed. Independence of parameters was tested by multivariate Cox regression.

RESULTS

∆SUV_max NTO and MTV were prognostic factors for all investigated clinical endpoints (OS, LC, DM, TF). Inclusion of clinical and PET tumour parameters in multivariate analysis showed that ∆SUV_max NTO was an independent prognostic factor. Furthermore, multivariate analysis of ∆SUV_max NTO using previously published cut-off values from preoperatively treated patients revealed that ∆SUV_max NTO was independent prognostic factor for OS (HR = 1.88, p = 0.038), TF (HR = 2.11, p = 0.048) and DM (HR = 3.02, p = 0.047).

CONCLUSION

NTO-related tracer uptake during the course of treatment in patients with oesophageal carcinoma was shown to be of high prognostic relevance. Thus, metabolically activity of NTO measured in terms of ∆SUV_max NTO is a potential candidate for future treatment individualization (i.e. organ preservation).

68Ga-PSMA PET/CT: Joint EANM and SNMMI procedure guideline for prostate cancer imaging: version 1.0

The aim of this guideline is to provide standards for the recommendation, performance, interpretation and reporting of ⁶⁸Ga-PSMA PET/CT for prostate cancer imaging. These recommendations will help to improve accuracy, precision, and repeatability of ⁶⁸Ga-PSMA PET/CT for prostate cancer essentially needed for implementation of this modality in science and routine clinical practice.

Predictive and prognostic value of 18F-DOPA PET/CT in patients affected by recurrent medullary carcinoma of the thyroid

INTRODUCTION

Medullary thyroid carcinoma (MTC) is a malignancy accounting for about 5-8% of thyroid cancers. Serum calcitonin and carcinoembryonic antigen (CEA) levels are widely used to monitor disease progression. However, prognostic factors able to predict outcomes are highly desirable. We, therefore, aimed to assess the prognostic role of ¹⁸F-DOPA PET/CT in patients with recurrent MTC.

MATERIALS AND METHODS

60 patients (mean age 64 ± 13 years, range 44-82) with recurrent MTC were eligible from a multicenter database. All patients underwent a restaging ¹⁸F-DOPA PET/CT, performed at least 6 months after surgery. CEA/calcitonin levels, local recurrences, nodal involvement and metastases at PET/CT were recorded. SUVmax, SUVmean (also normalized to mediastinal uptake) and metabolic tumor volume were automatically calculated for each lesion, by placing a volume of interest around the lesion with 40% of peak activity as threshold for the automatic contouring. The patients were clinically and radiologically followed up for 21 ± 11 months. Rate of progression-free survival (PFS), disease-specific survival (DSS) and incremental prognostic value of ¹⁸F-DOPA PET/CT over conventional imaging modalities were assessed by Kaplan-Meier curves and Log-Rank test. Cox regression univariate and multivariate analyses were performed for assessing predictors of prognosis.

RESULTS

¹⁸F-DOPA PET/CT showed abnormal findings in 27 patients (45%) and resulted unremarkable in 33 (55%). PFS was significantly longer in patients with an unremarkable PET/CT scan (p = 0.018). Similarly, an unremarkable PET/CT study was associated with a significantly longer DSS (p = 0.04). ¹⁸F-DOPA PET/CT added prognostic value over other imaging modalities both for PFS and for DSS (p < 0.001 and p = 0.012, respectively). Neither semiquantitative PET parameters nor clinical or laboratory data were predictive of a worse PFS and DSS in patients with recurrent MTC.

CONCLUSION

¹⁸F-DOPA PET/CT scan has an important prognostic value in predicting disease progression and mortality rate.

Neoadjuvant chemoradiotherapy of the rectal carcinoma - The correlation between the findings on the restaging multiparametric 3T MRI scanning and the surgical findings

AIM

To figure out how to correlate the findings on functional MRI and carried out after neoadjuvant CRT of rectal carcinoma with final histology after surgery.

BACKGROUND

Neoadjuvant CRT is the standard treatment of locally advanced rectal carcinoma. Its use leads to the downstaging of the disease and in 15-42% of patients even to the detection of pCR after TME. The use of functional MRI improves the sensitivity and specificity of pCR detection up to 52-64% and 89-98%, respectively.

MATERIALS AND METHODS

Between January 2013 and June 2016, 67 patients suffering from histologically proven locally advanced rectal cancer underwent neoadjuvant RT or CRT. We selected for further investigation only patients (33 patients) who underwent pelvic staging and restaging using multiparametric imaging on 3T MRI scanner. We compared the findings on functional MRI after neoadjuvant CRT with final histology after surgery.

RESULTS

In 15 patients pathologic staging of primary tumor differed from expected staging assessed according to preoperative MRI. In 5 patients pathologic complete remission was achieved. In none of these 5 patients pCR was predicted using preoperative MRI. Sensitivity and specificity of MRI in predicting pCR were 0% and 96%. Accuracy of MRI in predicting pT and pN was 79% and 74%.

CONCLUSIONS

We have verified that the use of neoadjuvant CRT in the treatment of locally advanced rectal carcinoma leads to a possible achievement of pCR. But in our group of patients this was not predictable nor was it with the use of multiparametric 3T MRI.

PET imaging for lymph node dissection in prostate cancer

The detection of neoplastic lymph nodal involvement in prostate cancer (PCa) patients has relevant therapeutic and prognostic significance, both in the clinical settings of primary staging and restaging. Lymph nodal dissection (LND) currently represents the gold standard for evaluating the presence of lymph nodal involvement. However, this procedure is invasive, associated with morbidity, and may fail in detecting all potential lymph nodal metastatic regions. Currently the criteria for lymph nodal detection using conventional imaging techniques mainly rely on morphological assessment with unsatisfactory diagnostic accuracy. Positron emission tomography (PET) represents a helpful imaging technique for a proper staging of lymph nodal status. The most investigated PET radiotracer is choline, although many others have been explored as guide for both primary and salvage LND, such as fluorodeoxyglucose, acetate, fluorocyclobutanecarboxylic acid and prostate-specific membrane antigen. In the present review, a comprehensive literature review addressing the role of PET for LND in PCa patients is reported, with the use of the above-mentioned radiotracers.

Recurrent bladder carcinoma: clinical and prognostic role of 18 F-FDG PET/CT

AIM

A small number of studies evaluated the detection rate of lesions from bladder carcinoma (BC) of 18 F-FDG PET/CT in the restaging process. However, the prognostic role of FDG PET/CT still remains unclear. The aim of the present study was to evaluate the accuracy, the effect upon treatment decision, and the prognostic value of FDG PET/CT in patients with suspected recurrent BC.

MATERIALS AND METHODS

Forty-one patients affected by BC underwent FDG PET/CT for restaging purpose. The diagnostic accuracy of visually interpreted FDG PET/CT was assessed compared to histology (n = 8), other diagnostic imaging modalities (contrast-enhanced CT in 38/41 patients and MRI in 15/41) and clinical follow-up (n = 41). Semiquantitative PET values (SUVmax, SUVmean, SUL, MTV, TLG) were calculated using a graph-based method. Progression-free survival (PFS) and overall survival (OS) were assessed by using Kaplan-Meier curves. The risk of progression (hazard ratio, HR) was computed by Cox regression analysis by considering all the available variables.

RESULTS

PET was considered positive in 21 of 41 patients. Of these, recurrent BC was confirmed in 20 (95 %). Sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of FDG PET/CT were 87 %, 94 %, 95 %, 85 %, 90 %. AUC was 0.9 (95 %IC 0.8-1). Bayesian positive and negative likelihood ratios were 14.5 and 0.13, respectively. FDG PET/CT findings modified the therapeutic approach in 16 patients (modified therapy in 10 PET-positive patients, watch-and-wait in six PET-negative patients). PFS was significantly longer in patients with negative scan vs. those with pathological findings (85 % vs. 24 %, p < 0.05; HR = 12.4; p = 0.001). Moreover, an unremarkable study was associated with a longer OS (88 % vs. 47 % after 2 years and 87 % vs. 25 % after 3 years, respectively, p < 0.05). Standardized uptake value (SUV)max > 6 and total lesion glycolysis (TLG) > 8.5 were recognized as the most accurate thresholds to predict PFS (2-year PFS 62 % for SUVmax < 6 vs. 15 % for SUVmax > 6, p = 0.018; 2-year PFS 66 % for TLG < 8.5 vs. 18 % for TLG > 8.5, p = 0.09).

CONCLUSION

A very good diagnostic performance for FDG PET/CT was confirmed in patients with suspected recurrent BC. FDG PET/CT allowed for a change in treatment decision in about 40 % of cases and showed an important prognostic value in assessing PFS and OS.

Restaging after neoadjuvant chemoradiation in rectal cancers: is histology the key in patient selection?

BACKGROUND

Neoadjuvant chemoradiation is the standard of care for locally advanced rectal cancer. However, there is no clarity regarding the necessity for restaging scans to rule out systemic progression of disease post chemoradiation with existing literature being divided on the need for the same.

METHODS

Data from a prospectively maintained database was retrospectively analysed. All locally advanced rectal cancers (node positive/T4/T3 with threatened or involved CRM) were included. Biopsy proof of adenocarcinoma and CT scan of abdomen and chest were mandatory. Grade of tumor and response to CTRT on restaging magnetic resonance imaging (MRI) were documented.

RESULTS

Out of 119 patients subjected to CTRT, 72 underwent definitive total mesorectal excision while 13 patients progressed locoregionally on restaging MR pelvis and 15 other patients progressed systemically while the rest defaulted. Patients with poorly differentiated (PD) cancers were compared to those with well/moderately differentiated (WMD) tumors. PD tumors had a significantly higher rate of local progression (32.1% vs. 5.6% %, P=0.0011) and systemic progression (35.7% vs. 6.9%, P=0.0008) as compared to WMD tumors. Only one-third (9/28) of PD patients underwent TME while the rest progressed.

CONCLUSIONS

Selecting poorly differentiated tumors alone for restaging CECT abdomen and thorax will be a cost effective strategy as the rate of progression is very high. Also patients with PD tumors need to be consulted about the high probability of progression of disease.

Acquisition with (11)C-choline and (18)F-fluorocholine PET/CT for patients with biochemical recurrence of prostate cancer: a systematic review and meta-analysis

The objective of the systematic review and meta-analysis was to evaluate whether the choice between two radiotracers, (11)C-choline ((11)C-cho) and (18)F-fluorocholine ((18)F-FCH) for PET/CT, and different acquisition protocols contributed to detect metastases for patients with biochemical recurrence of prostate cancer after radical prostatectomy or radiotherapy. We searched in January 2016 in Pubmed and Embase for articles that had used radiolabeled choline PET/CT in restaging. The meta-analysis evaluated technical and clinical aspects. Across 18 articles 1 219 of 2 213 patients (54.9 %) had a positive radiolabeled PET/CT image. Mean of the mean/median restaging PSA levels was 3.6 ± 2.7 ng/mL (range 0.5-10.7 ng/mL). Six articles with (11)C-cho PET/CT had a radiation activity of 561 ± 122 MBq and it was 293 ± 47 MBq in 12 articles with (18)F-FCH PET/CT. The difference was significant (P = 0.007, t test). Uptake time was 5 min in articles with (11)C-cho PET/CT and it was 29 ± 24 min in articles with (18)F-FCH PET/CT. The difference was significant (P = 0.02, t test). Thereby the detection rates of metastatic sites in articles with (11)C-cho (30 ± 5 %) and (18)F-FCH (39 ± 5 %) did not differ significantly (P = 0.26, t test). In linear regression analyses of the articles, the radiation activity of (11)C-cho and (18)F-FCH was not significantly associated with the detection rate of metastatic sites (P = 0.75 and P = 0.60). Restaging with radiolabeled choline PET/CT detected metastatic sites for patients with biochemical recurrence and PSA levels of 1-10 ng/mL at clinically relevant level. The choice between the two choline radiotracers and different acquisition protocols had no significant impact on detection.

Positron emission tomography in imaging evaluation of staging, restaging, treatment response, and prognosis in prostate cancer

Prostate cancer is a prevalent public health problem worldwide. While imaging has played a major role in this disease, there still remain many challenges and opportunities. Positron emission tomography with various physiologically based radiotracers is fundamentally suited to interrogate this biologically and clinically heterogeneous disease along the course of its natural history. In this article, I review briefly the published evidence for the use of positron emission tomography with 18F-fluorodeoxyglucose, 11C-acetate, and 18F- or 11C-choline in the imaging evaluation of prostate cancer. Although the focus of the article will be on these radiotracers given the accumulated experience with them, but I will also comment on the outlook for the use of other emerging PET radiotracers such as those targeted to the prostate-specific membrane antigen and the amino acid metabolism pathway. It is anticipated that PET will play major role in the evaluation of prostate cancer in the current evidence-based medicine environment. There will also be exciting novel prospects for the use of therapeutic-diagnostic (theransotic) pairs in the management of patients with prostate cancer.

Predictive value of (18)F-FDG PET/CT in restaging patients affected by ovarian carcinoma: a multicentre study

PURPOSE

Ovarian cancer is the eighth most common malignancy among women and has a high mortality rate. Prognostic factors able to drive an effective therapy are essential. (18)F-Fluoro-2-deoxyglucose positron emission tomography/computed tomography ((18)F-FDG PET/CT) has been investigated in patients with epithelial ovarian cancer and showed promise in diagnosing, staging, detecting recurrent lesions and monitoring treatment response. Conversely, its prognostic role remains unclear. We aimed at assessing the prognostic value of (18)F-FDG PET/CT performed in the restaging process in a multicentre study.

METHODS

We evaluated 168 patients affected by ovarian carcinoma, who underwent a restaging (18)F-FDG PET/CT. The presence of local recurrences, lymph node involvement and distant metastasis was recorded as well as lesion dimensions, maximum and mean standardized uptake values (SUVmax and SUVmean, respectively). Progression-free survival (PFS) and overall survival (OS) at 3 and 4 years were computed by using Kaplan-Meier curves. Increased odds ratio was assessed using Cox regression analysis testing all lesion parameters measured by PET/CT.

RESULTS

PFS was significantly longer in patients with a negative than a positive restaging PET/CT study (3- and 4-year PFS 64 and 53% vs 23 and 12%, respectively; p < 0.001). Similarly, a negative study was associated with a significantly higher OS rate after 4 years of follow-up (67 vs 25% in negative and positive groups, respectively; p < 0.001). Lymph node or distant involvement were also independently associated with an increased risk of disease progression [hazard ratio (HR) 1.6 and 2.2, respectively; p = 0.003]. Moreover, PET/CT showed an incremental prognostic value compared to the International Federation of Gynecology and Obstetrics (FIGO) staging system. In the analysis of patient subsets, individuals with the same FIGO stage I-II but with negative PET had a significantly better 4-year OS than patients with low FIGO stage but positive PET. This implies that patients with the same FIGO stage can be further prognostically stratified using PET (p = 0.01). At receiver-operating characteristic (ROC) analysis, no thresholds for semiquantitative parameters were predictive of a worse outcome.

CONCLUSION

(18)F-FDG PET/CT has an important prognostic value in assessing the risk of disease progression and mortality rate. An efficacious therapy planning might therefore effectively rely on (18)F-FDG PET/CT findings. Semiquantitative data were not proven to be an effective tool to predict disease progression.

Somatostatin receptor PET/CT in restaging of typical and atypical lung carcinoids

Background

To assess the role of somatostatin receptor (SR) PET/CT using Ga-68 DOTATOC or DOTATATE in staging and restaging of typical (TC) and atypical (AC) lung carcinoids.

Methods

Clinical and PET/CT data were retrospectively analyzed in 27 patients referred for staging (N = 5; TC, N = 4; AC, N = 1) or restaging (N = 22; TC, N = 8; AC, N = 14). Maximum standardized uptake value (SUVmax) of SR-positive lesions was normalized to the SUVmax of the liver to generate SUVratio; SR PET was compared to contrast-enhanced (ce) CT. The classification system proposed by Rindi et al. (Endocr Relat Cancer. 2014;21(1):1-16, 2014) was used for classification of patients in TC and AC groups.

Results

Only 18/27 patients were found to have metastases on PET/CT. Of the 186 lesions, 101 (54.3 %) were depicted on both PET and CT, 53 (28.5 %) lesions only on CT, and 32 (17.2 %) only on PET. SUVratio of lesions was significantly higher in AC as compared to TC (p < 0.001). In patients referred for restaging, additional findings on PET lead to upstaging with change in management strategy in 5/22 (22.7 %) patients (AC, N = 5; TC, N = 1). In four patients (all AC) referred for restaging and in one patient (TC) referred for staging, additional findings on CT missed on PET lead to correct staging.

Conclusions

Typical and atypical carcinoid patients have complex patterns of metastases which make it necessary to combine functional SR PET and contrast-enhanced CT for appropriate restaging. In patients referred for restaging SR, PET may have a relevant impact on treatment strategy in up to 22.7 of patients with typical and atypical lung carcinoids.

Factors affecting the restaging accuracy of magnetic resonance imaging after preoperative chemoradiation in patients with rectal cancer

PURPOSES

We evaluated patient or tumor factors associated with the preoperative restaging accuracy of magnetic resonance imaging (MRI) for determining T and N stages as well as circumferential resection margin (CRM) involvement after chemoradiation (CRT) in patients with locally advanced rectal cancer.

METHODS

Seventy-seven patients with rectal cancer that were treated with preoperative CRT (50.4 Gy) followed by radical resection were included. Post-CRT MRI was performed approximately 4 weeks after preoperative CRT.

RESULTS

The median tumor distance from the anal verge was 6 cm, 48 (62%) of which were anterior and 29 (38%) posterior. The median tumor diameter was 3 cm. A stage-by-stage comparison showed that correct staging occurred in 62%, 43%, and 86% of patients for T staging, N staging, and CRM prediction, respectively. Shorter distance to the anal verge (<5 cm), smaller tumor diameter (<1 cm), and anterior tumor location were associated with incorrect T staging. There were no significant variables in terms of N staging accuracy. Shorter tumor distance and anterior tumor location were associated with incorrect CRM prediction.

CONCLUSIONS

Our findings suggest that specific tumor factors such as small, distal, or anterior rectal tumors are closely associated with the accuracy of MRI after preoperative CRT.

Prediction of pathologic staging with magnetic resonance imaging after preoperative chemoradiotherapy in rectal cancer: pooled analysis of KROG 10-01 and 11-02

BACKGROUND AND PURPOSE

The reported overall accuracy of MRI in predicting the pathologic stage of nonirradiated rectal cancer is high. However, the role of MRI in restaging rectal tumors after neoadjuvant CRT is contentious. Thus, we evaluate the accuracy of restaging magnetic resonance imaging (MRI) for rectal cancer patients who receive preoperative chemoradiotherapy (CRT).

METHODS AND MATERIALS

We analyzed 150 patients with locally advanced rectal cancer (T3-4N0-2) who had received preoperative CRT. Pre-CRT MRI was performed for local tumor and nodal staging. All patients underwent restaging MRI followed by total mesorectal excision after the end of radiotherapy. The primary endpoint of the present study was to estimate the accuracy of post-CRT MRI as compared with pathologic staging.

RESULTS

Pathologic T classification matched the post-CRT MRI findings in 97 (64.7%) of 150 patients. 36 (24.0%) of 150 patients were overstaged in T classification, and the concordance degree was moderate (k=0.33, p<0.01). Pathologic N classification matched the post-CRI MRI findings in 85 (56.6%) of 150 patients. 54 (36.0%) of 150 patients were overstaged in N classification. 26 patients achieved downstaging (ycT0-2N0) on restaging MRI after CRT. 23 (88.5%) of 26 patients who had been downstaged on MRI after CRT were confirmed on the pathological staging, and the concordance degree was good (k=0.72, p<0.01).

CONCLUSIONS

Restaging MRI has low accuracy for the prediction of the pathologic T and N classifications in rectal cancer patients who received preoperative CRT. The diagnostic accuracy of restaging MRI is relatively high in rectal cancer patients who achieved clinical downstaging after CRT.

¹⁸F-FDG-PET/CT in staging, restaging, and treatment response assessment of male breast cancer

PURPOSE

Male breast cancer (BC) is a rare disease, with patterns different from those found in women. Most tumors are detected at more advanced stages than in women. The aim of this study was to analyze the performance of [18F]fluorodeoxyglucose positron emission tomography/computed tomography ((18)F-FDG-PET/CT) in staging, restaging, and therapy response assessment.

METHODS

We performed a systematic analysis in the database of Saint-Louis Hospital to identify male patients with BC referred for PET/CT. (18)F-FDG-PET/CT findings considered suspicious for malignancy were compared to biopsy results, further work-up and/or patient follow-up of at least 6 months. Performances of (18)F-FDG-PET/CT were compared to that of conventional imaging (CI) using the McNemar test. The impact of PET/CT on management was evaluated.

RESULTS

During 6 consecutive years, among 12,692 (18)F-FDG-PET/CT oncology studies, 30 were performed in 15 men with BC: 7 examinations for initial staging, 11 for restaging, and 12 for response assessment. Tumors profile was ER+ and one had HER2 overexpression. PET/CT sensitivity, specificity, positive predictive value, negative predictive value and accuracy to detect distant metastases were 100%, 67%, 86%, 100% and 89%, respectively. PET/CT was more informative than CI in 40% of studies (p=0.03; 95% confidence interval: 3.26 - 40%). Findings from (18)F-FDG-PET/CT led to modification in the planned treatment in 13/30 cases (43%).

CONCLUSION

Although all the tumors were ER+, primary lesions and metastases were diagnosed with high sensitivity. (18)F-FDG-PET/CT seems to be a powerful imaging method to perform staging, restaging and treatment response assessment in male patients with BC.

Multimodal imaging evaluation in staging of rectal cancer

Rectal cancer is a common cancer and a major cause of mortality in Western countries. Accurate staging is essential for determining the optimal treatment strategies and planning appropriate surgical procedures to control rectal cancer. Endorectal ultrasonography (EUS) is suitable for assessing the extent of tumor invasion, particularly in early-stage or superficial rectal cancer cases. In advanced cases with distant metastases, computed tomography (CT) is the primary approach used to evaluate the disease. Magnetic resonance imaging (MRI) is often used to assess preoperative staging and the circumferential resection margin involvement, which assists in evaluating a patient’s risk of recurrence and their optimal therapeutic strategy. Positron emission tomography (PET)-CT may be useful in detecting occult synchronous tumors or metastases at the time of initial presentation. Restaging after neoadjuvant chemoradiotherapy (CRT) remains a challenge with all modalities because it is difficult to reliably differentiate between the tumor mass and other radiation-induced changes in the images. EUS does not appear to have a useful role in post-therapeutic response assessments. Although CT is most commonly used to evaluate treatment responses, its utility for identifying and following-up metastatic lesions is limited. Preoperative high-resolution MRI in combination with diffusion-weighted imaging, and/or PET-CT could provide valuable prognostic information for rectal cancer patients with locally advanced disease receiving preoperative CRT. Based on these results, we conclude that a combination of multimodal imaging methods should be used to precisely assess the restaging of rectal cancer following CRT.

Revised ESTS guidelines for preoperative mediastinal lymph node staging for non-small-cell lung cancer

Accurate preoperative staging and restaging of mediastinal lymph nodes in patients with potentially resectable non-small-cell lung cancer (NSCLC) is of paramount importance. In 2007, the European Society of Thoracic Surgeons (ESTS) published an algorithm on preoperative mediastinal staging integrating imaging, endoscopic and surgical techniques. In 2009, the International Association for the Study of Lung Cancer (IASLC) introduced a new lymph node map. Some changes in this map have an important impact on mediastinal staging. Moreover, more evidence of the different mediastinal staging technique has become available. Therefore, a revision of the ESTS guidelines was needed. In case of computed tomography (CT)-enlarged or positron emission tomography (PET)-positive mediastinal lymph nodes, tissue confirmation is indicated. Endosonography [endobronchial ultrasonography (EBUS)/esophageal ultrasonography (EUS)] with fine-needle aspiration (FNA) is the first choice (when available), since it is minimally invasive and has a high sensitivity to rule in mediastinal nodal disease. If negative, surgical staging with nodal dissection or biopsy is indicated. Video-assisted mediastinoscopy is preferred to mediastinoscopy. The combined use of endoscopic staging and surgical staging results in the highest accuracy. When there are no enlarged lymph nodes on CT and when there is no uptake in lymph nodes on PET or PET-CT, direct surgical resection with systematic nodal dissection is indicated for tumours ≤ 3 cm located in the outer third of the lung. In central tumours or N1 nodes, preoperative mediastinal staging is indicated. The choice between endoscopic staging with EBUS/EUS and FNA or video-assisted mediastinoscopy depends on local expertise to adhere to minimal requirements for staging. For tumours >3 cm, preoperative mediastinal staging is advised, mainly in adenocarcinoma with high standardized uptake value. For restaging, invasive techniques providing histological information are advisable. Both endoscopic techniques and surgical procedures are available, but their negative predictive value is lower compared with the results obtained in baseline staging. An integrated strategy using endoscopic staging techniques to prove mediastinal nodal disease and mediastinoscopy to assess nodal response after induction therapy needs further study.

Accurate and safe mediastinal restaging by combined endobronchial and endoscopic ultrasound-guided needle aspiration performed by single ultrasound bronchoscope

OBJECTIVES

The aim of this prospective trial was to assess the diagnostic utility of combined endobronchial (EBUS) and endoscopic (EUS) ultrasound-guided needle aspiration by use of a single ultrasound bronchoscope (CUSb-NA) in non-small-cell lung cancer (NSCLC) restaging in patients after induction therapy.

METHODS

In a consecutive group of NSCLC patients with pathologically confirmed N2 disease (clinical stage IIIa and IIIb) who underwent induction chemotherapy, CUSb-NA was performed. All of the patients with negative or suspected for metastases (uncertain) diagnosed by endoscopy underwent subsequently transcervical extended mediastinal lymphadenectomy (TEMLA) as a confirmatory test.

RESULTS

From January 2009 to December 2012, 106 patients met the inclusion criteria and underwent restaging CUSb-NA under mild sedation, in whom 286 (mean 2.7, range 2-5) lymph node stations were biopsied, 127 (mean 1.2, range 1-3) by EBUS-transbronchial needle aspiration (TBNA) and 159 (mean 1.5, range 1-4) by EUS-fine needle aspiration (FNA). The CUSb-NA revealed metastatic lymph node involvement in 37/106 patients (34.9%). In 69 (65.1%) patients with negative and uncertain CUSb-NA in 4 (3.8%) out of them, who underwent subsequent TEMLA metastatic nodes were found in 18 patients (17.0%) and there were single lymph nodes found only in one mediastinal station (minimal N2) in 10 (9.4%) out of them. False-positive results were found in 2 (1.9%) patients. In 9 (8.5%) patients CUSb-NA occurred to be false negative in Stations 2R and 4R (only accessible for EBUS), exclusively in small nodes and in 4 (3.8%) patients in Station 5-not accessible for CUSb-NA. The prevalence of mediastinal lymph node metastases in the present study was 51.9%. Diagnostic sensitivity, specificity, total accuracy, positive predictive value and negative predictive value (NPV) of the restaging CUSb-NA were 67.3% (95% CI [confidence interval]-53-79), 96.0% (95% CI-86-99), 81.0% (95% CI-73-87), 95.0% (95% CI-83-99) and 73.0% (95% CI-61-83), respectively. The sensitivity, accuracy and NPV of CUSb-NA were higher compared with EBUS-TBNA and EUS-FNA alone. No complications of CUSb-NA were observed.

CONCLUSIONS

The CUSb-NA is a reasonable and safe technique in mediastinal restaging in NSCLC patients after induction therapy. Following our data, in patients with negative result of CUSb-NA, a surgical restaging of the mediastinum should be considered.

How reliable is current imaging in restaging rectal cancer after neoadjuvant therapy?

In patients with advanced rectal cancer, neoadjuvant chemo radiotherapy provides tumor downstaging and downsizing and complete pathological response in up to 30% of cases. After proctectomy complete pathological response is associated with low rates of local recurrence and excellent long term survival. Several authors claim a less invasive surgery or a non operative policy in patients with partial or clinical complete response respectively, however to identify patients with true complete pathological response before surgical resection remains a challenge. Current imaging techniques have been reported to be highly accurate in the primary staging of rectal cancer, however neoadjuvant therapy course produces deep modifications on cancer tissue and on surrounding structures such as overgrowth fibrosis, deep stroma alteration, wall thickness, muscle disarrangement, tumor necrosis, calcification, and inflammatory infiltration. As a result, the same imaging techniques, when used for restaging, are far less accurate. Local tumor extent may be overestimated or underestimated. The diagnostic accuracy of clinical examination, rectal ultrasound, computed tomography, magnetic resonance imaging, and positron emission tomography using 18F-fluoro-2’-deoxy-D-glucose ranges between 25% and 75% being less than 60% in most studies, both for rectal wall invasion and for lymph nodes involvement. In particular the ability to predict complete pathological response, in order to tailor the surgical approach, remains low. Due to the radio-induced tissue modifications, combined with imaging technical aspects, low rate accuracy is achieved, making modern imaging techniques still unreliable in restaging rectal cancer after chemo-radiotherapy.

Role of F18-FDG PET/CT in the Staging and Restaging of Esophageal Cancer: A Comparison with CECT

Esophageal cancer is one of the most fatal cancers principally because of its late presentation. CECT plays an important role in the staging of esophageal cancer but has some limitations. PET/CT which provides physiological information along with anatomical information and is a whole body imaging technique may therefore be a better alternative and thereby can facilitate selection or exclusion of patients for resection. The aim was to evaluate the performance of F18 FDG PET/CT in the staging and restaging of esophageal carcinoma compared to CECT using histopathologic findings and clinical follow-up as gold standard. Twenty eight patients with proven esophageal carcinoma, both preoperative and postoperative, were studied with CECT and F18 FDG PET/CT scan within an interval of 2 weeks. The PET/CT scan was acquired after injection of 370 MBq (10 mCi) F18-FDG and was evaluated for areas of increased focal uptake. CECT scan of chest and abdomen was done after injection of iodinated non-ionic contrast media. CECT findings suggested stage-IV disease in 16/28 (57.14%) patients and non stage-IV disease in 12/28 (42.86%) patients, whereas PET/CT suggested stage-IV disease in 23/28 (82.14%) patients and non stage-IV disease in 5/28 (17.86%) patients. Total nine patients were upstaged by PET/CT compared to CECT, out of which 7 (25%) were correctly upstaged and 2 (7.14%) were falsely upstaged. PET/CT improved our ability to detect distant metastases in 25% of patients that was missed by CECT. So, the use of F18 FDG PET/CT in esophageal cancer can alter management in significant number of patients.

FDG-PET/CT and parathyroid carcinoma: Review of literature and illustrative case series

Parathyroid cancer is an uncommon malignant cancer and is associated with a poor prognosis. The staging of parathyroid cancer represents an important issue both at initial diagnosis and after surgery and medical treatment. The role of positron emission tomography/computed tomography (PET/CT) with 18F-Fluorodeoxyglucose (18F-FDG) as an imaging tool in parathyroid cancer is not clearly reported in the literature, although its impact in other cancers is well-defined. The aim of the following illustrative clinical cases is to highlight the impact of PET/CT in the management of different phases of parathyroid cancer. We describe five patients with parathyroid malignant lesions, who underwent FDG PET/CT at initial staging, restaging and post-surgery evaluation. In each patient we report the value of PET/CT comparing its findings with other common imaging modalities (e.g., CT, planar scintigraphy with 99mTc-sestamibi, magnetic resonance imaging) thus determining the complementary benefit of FDG PET/CT in parathyroid carcinoma. We hope to provide an insight into the potential role of PET/CT in assessing the extent of disease and response to treatment which are the general principles used to correctly evaluate disease status.

Metabolic restaging of hepatocellular carcinoma using whole-body F-FDG PET/CT

AIM

To evaluate the ability of (18)F-fluorodeoxyglucose positron emission and computed tomography ((18)F-FDG PET/CT) in restaging of hepatocellular carcinoma (HCC) after treatment.

METHODS

We reviewed a database of the diagnostic performance of (18)F-FDG PET/CT scan for patients with HCC following local or regional treatment. The database consisted of (18)F-FDG PET/CT information of 21 male and 4 female (age range, 27-81 years; mean age, 51.6 years) patients who had received surgical resection and/or interventional treatments and then underwent (18)F-FDG PET/CT scan. All patients had received enhanced CT scan of the liver two weeks before or after the (18)F-FDG PET/CT scan. Intrahepatic recurrence and/or extrahepatic metastases were confirmed by histological analysis or clinical and imaging follow-up. The accuracy of (18)F-FDG PET/CT study was determined by histopathological results or by clinical and imaging follow-up.

RESULTS

(18)F-FDG PET/CT was abnormal in 19 of the 25 (76.0%) patients. In detecting HCC recurrence, (18)F-FDG PET/CT scored 17 true positives, 5 true negatives, 2 false positives and 1 false negative. The sensitivity, specificity and accuracy of (18)F-FDG PET/CT in detecting HCC recurrence was 89.5%, 83.3% and 88%, respectively. (18)F-FDG PET/CT had an impact on management of these patients by settling the problem of an unexplained increase in alpha-fetoprotein after treatment (14 patients), by monitoring response to the treatment and guiding additional regional therapy (12 patients), by identifying extrahepatic metastases (10 patients), by identifying tumor growth or thrombosis in the portal vein (6 patients), or by guiding surgical resection of extrahepatic metastases (2 patients).

CONCLUSION

Our results suggest that whole body (18)F-FDG PET/CT may be useful in the early evaluation of residual, intrahepatic recurrent or extrahepatic metastatic lesions and able to provide valuable information for the management of HCC recurrence.

Clinical value of 18F-FDG PET/CT in assessing suspicious relapse after rectal cancer resection

AIM: To evaluate the value of ¹⁸F-fluorodeoxyglucose positron emission tomography/computed tomography (¹⁸F-FDG PET/CT) in the restaging of resected rectal cancer.

METHODS: From January 2007 to Sep 2008, 21 patients who had undergone curative surgery resection for rectal carcinoma with suspicious relapse in conventional imaging or clinical findings were retrospectively enrolled in our study. The patients underwent 28 PET/CT scans (two patients had two scans, one patient had three and one had four scans). Locoregional recurrences and/or distant metastases were confirmed by histological analysis or clinical and imaging follow-up.

RESULTS: Final diagnosis was confirmed by histopathological diagnosis in 12 patients (57.1%) and by clinical and imaging follow-up in nine patients (42.9%). Eight patients had extrapelvic metastases with no evidence of pelvic recurrence. Seven patients had both pelvic recurrence and extrapelvic metastases, and two patients had pelvic recurrence only. ¹⁸F-FDG PET/CT was negative in two patients and positive in 19 patients. ¹⁸F-FDG PET/CT was true positive in 17 patients and false positive in two. The accuracy of ¹⁸F-FDG PET/CT was 90.5%, negative predictive value was 100%, and positive predictive value was 89.5%. Five patients with perirectal recurrence underwent ¹⁸F-FDG PET/CT image guided tissue core biopsy. ¹⁸F-FDG PET/CT also guided surgical resection of pulmonary metastases in three patients and monitored the response to salvage chemotherapy and/or radiotherapy in four patients.

CONCLUSION: ¹⁸F-FDG PET/CT is useful for evaluating suspicious locoregional recurrence and distant metastases in the restaging of rectal cancer after curative resection.

Clinical usefulness of 18F-FDG PET/CT in the restaging of esophageal cancer after surgical resection and radiotherapy

AIM: To evaluate the clinical usefulness of ¹⁸F-fluorodeoxyglucose positron emission and computed tomography (¹⁸F-FDG PET/CT) in restaging of esophageal cancer after surgical resection and radiotherapy.

METHODS: Between January 2007 and Aug 2008, twenty histopathologically diagnosed esophageal cancer patients underwent 25 PET/CT scans (three patients had two scans and one patient had three scans) for restaging after surgical resection and radiotherapy. The standard reference for tumor recurrence was histopathologic confirmation or clinical follow-up for at least ten months after ¹⁸F-FDG PET/CT examinations.

RESULTS: Tumor recurrence was confirmed histopathologically in seven of the 20 patients (35%) and by clinical and radiological follow-up in 13 (65%). ¹⁸F-FDG PET/CT was positive in 14 patients (68.4%) and negative in six (31.6%). ¹⁸F-FDG PET/CT was true positive in 11 patients, false positive in three and true negative in six. Overall, the accuracy of ¹⁸F-FDG PET/CT was 85%, negative predictive value (NPV) was 100%, and positive predictive value (PPV) was 78.6%. The three false positive PET/CT findings comprised chronic inflammation of mediastinal lymph nodes (n = 2) and anastomosis inflammation (n = 1). PET/CT demonstrated distant metastasis in 10 patients. ¹⁸F-FDG PET/CT imaging-guided salvage treatment in nine patients was performed. Treatment regimens were changed in 12 (60%) patients after introducing ¹⁸F-FDG PET/CT into their conventional post-treatment follow-up program.

CONCLUSION: Whole body ¹⁸F-FDG PET/CT is effective in detecting relapse of esophageal cancer after surgical resection and radiotherapy. It could also have important clinical impact on the management of esophageal cancer, influencing both clinical restaging and salvage treatment of patients.