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Imaging in oncology is an essential tool for patient management but its potential is being profoundly underutilized. Each of the techniques used in the diagnostic process also conveys functional information that can be relevant in treatment decision-making. New imaging algorithms and techniques enhance our knowledge about the phenotype of the tumor and its potential response to different therapies. Functional imaging can be defined as the one that provides information beyond the purely morphological data, and include all the techniques that make it possible to measure specific physiological functions of the tumor, whereas molecular imaging would include techniques that allow us to measure metabolic changes. Functional and molecular techniques included in this document are based on multi-detector computed tomography (CT), 18F-fluorodeoxyglucose positron emission tomography (18F-FDG PET), magnetic resonance imaging (MRI), and hybrid equipments, integrating PET with CT (PET/CT) or MRI (PET-MRI). Lung cancer is one of the most frequent and deadly tumors although survival is increasing thanks to advances in diagnostic methods and new treatments. This increased survival poises challenges in terms of proper follow-up and definitions of response and progression, as exemplified by immune therapy-related pseudoprogression. In this consensus document, the use of functional and molecular imaging techniques will be addressed to exploit their current potential and explore future applications in the diagnosis, evaluation of response and detection of recurrence of advanced NSCLC.

Introduction: 18F-FDG PET has demonstrated its usefulness in detecting recurrences of differentiated thyroid cancer (DTC) with high thyroglobulin (Tg) levels and negative 131I whole-body scan (WBS); however, the number of patients analyzed is low and different studies report disparate results., Objective: To estimate the diagnostic accuracy of 18F-FDG PET in this subgroup of patients., Materials and Methods: Fifty eight patients (64 18F-FDG PET studies) with histologically proven DTC treated with total thyroidectomy followed by at least one session of 131I therapy for the ablation of thyroid remnants were retrospectively analyzed. Results were verified by pathology, clinical follow-up, response to treatment, or by comparison with conventional diagnostic methods. Sensitivity (Se), specificity (Sp), likelihood ratios (LR), diagnostic accuracy (DA), positive and negative predictive values (PPV, NPV), and Tg levels were calculated for patients with positive and negative 18F-FDG PET results., Results: Twenty seven studies were true positives, 1 false positive, 25 true negatives, and 11 false negatives. Se was 71 %, Sp 96 %, PPV 96.4 %; NPV 69.4 %, DA 81.3 %, positive LR 17.75, and negative LR 0.3. The mean Tg level was 202.34 ng/ml in patients with positive 18F-FDG PET and 40.94 ng/ml in those with negative 18F-FDG PET; the difference between the two groups (161.4 ng/ml) was significant at p <0.05., Conclusions: 18F-FDG PET is a useful for detecting residual or recurrent DTC in patients with elevated Tg and negative 131I WBS.

Background: This study aimed to assess the results obtained with the positron emission tomography (PET) and conventional anatomic imaging methods (CT scan and MRI) in the diagnosis of suspicion of tumor recurrence in head and neck cancers., Methods: Thirty patients with suspicion of tumor recurrence due to head and neck cancers were reviewed retrospectively. Consequently, 34 PET studies were performed. The images were obtained in the PET Institute of Madrid. They were interpreted by visual and semiquantitative analysis. The results were confirmed with clinical follow-up, response to treatment or with histological studies in some cases., Results: Sensitivity and specificity of the PET were 95.6% and 81.8% respectively, while it was 65% and 80% for the CT scan/MRI., Conclusions: We can conclude that PET provides better results than conventional imaging techniques in the detection of head and neck cancer recurrence.

Objective: To present the case report of a patient with undifferentiated and diffuse signet-ring cell gastric carcinoma in which FDG-PET evidenced recurrent disease., Materials and Methods: The patient was diagnosed of a stage III gastric carcinoma in 1994 and was treated with a subtotal gastrectomy. In February 2003, recurrent disease was detected in mediastinal and left supraclavicular lymph nodes. The patient was treated with chemotherapy and radiotherapy, reaching a complete response. After 6 months free of disease, he presented an elevation of the tumor markers with negative results in conventional imaging methods (upper digestive endoscopy, bone scintigraphy, and CT). An FDG-PET scan was performed to rule out recurrent disease., Results: FDG-PET detected pathologic findings suggestive of malignant disease in right supraclavicular and mediastinal lymph nodes. These findings were confirmed by clinical follow-up and with another CT scan performed 4 months later., Conclusions: In this case report we stress the importance of early recurrence by FDG-PET in a non-intestinal gastric carcinoma. This is of interest given the greater difficulty to detect mucous secreting and/or producing carcinomas with the PET-FDG.

Aim: Recurrent ovarian cancer is a major problem and an accurate diagnosis can often change patients' management. This study aimed to assess the impact on management of FDG-PET in recurrent ovarian cancer., Material and Methods: Forty-three patients in whom FDG-PET scan was performed due to suspected recurrent ovarian cancer were included. FDG-PET results were confirmed by histopathology and clinical follow-up of at least 12 months. To assess impact on management the treatment plan based on conventional imaging methods was compared with the treatment plan based on inclusion of PET findings, classifying FDG-PET impact on management as high, medium, low or no impact. Management changes, when present, were classified as intermodality or intramodality., Results: FDG-PET had a high impact on therapeutic management in 28 patients (65.1 %), medium impact in 2 patients (4.6 %), low impact in 9 patients (20.9 %), and no impact in 4 patients (9.3 %). FDG-PET induced an intermodality change in management in 27 patients (62,8 %); intramodality changes were induced in 3 patients (7 %). Finally, it produced no treatment changes in 13 patients (30.2 %)., Conclusion: FDG-PET supplied additional information when compared to conventional diagnostic procedures and allowed adequate management changes in most patients.