Melanoma is an important public health problem, and its incidence is increasing worldwide. The disease status of regional lymph nodes is the most important prognostic factor in early-stage melanoma patients. Sentinel lymph node biopsy (SLNB) was introduced in the early 1990s as a less invasive procedure than complete lymph node dissection to allow histopathologic evaluation of the "sentinel lymph node" (SLN), which is the first node along the lymphatic pathway from a primary tumor. Sentinel lymph node biopsy has minimal complication risks compared with standard complete lymph node dissection. Currently, SLNB is the accepted method for staging patients with clinically node-negative cutaneous melanoma and provides the most powerful prognostic information by evaluating the nodal basin status. The current practice of SLNB consists of the injection of Tc-labeled radiopharmaceutical, preoperative lymphoscintigraphy with the possibility of using the SPECT/CT hybrid imaging, and intraoperative SLN localization using a handheld gamma probe with or without the use of blue dye. Recently, the SLN localization and detection have been enhanced with the use of new tracers and new intraoperative devices, which have demonstrated to be particularly useful in melanomas of the head and neck region and in area of complex anatomy. Despite these important advances in the technology and the increasing experience in SLN mapping, major research centers have reported a false-negative rate higher than 15%. This relatively high false-negative rate, greater than those reported in the initial validation studies, points out the importance for the nuclear medicine community to continuously improve their knowledge on the biological behavior of melanoma and to improve the technical aspects that may allow more precise staging. For the SLNB procedure to be accurate, it is of critical importance that all "true" SLNs are identified and removed for examination. The aim of this article is to provide general information about the SLNB procedure in clinical practice highlighting the importance of standardization and accuracy of SLN identification in the light of the most recent technical innovations.

Axillary lymph node status, a major prognostic factor in early-stage breast cancer, provides information important for individualized surgical treatment. Because imaging techniques have limited sensitivity to detect metastasis in axillary lymph nodes, the axilla must be explored surgically. The histology of all resected nodes at the time of axillary lymph node dissection (ALND) has traditionally been regarded as the most accurate method for assessing metastatic spread of disease to the locoregional lymph nodes. However, ALND may result in lymphedema, nerve injury, shoulder dysfunction, and other short-term and long-term complications limiting functionality and reducing quality of life. Sentinel lymph node biopsy (SLNB) is a less invasive method of assessing nodal involvement. The concept of SLNB is based on the notion that tumors drain in an orderly manner through the lymphatic system. Therefore, the SLN is the first to be affected by metastasis if the tumor has spread, and a tumor-free SLN makes it highly unlikely for other nodes to be affected. Sentinel lymph node biopsy has become the standard of care for primary treatment of early breast cancer and has replaced ALND to stage clinically node-negative patients, thus reducing ALND-associated morbidity. More than 20 years after its introduction, there are still aspects concerning SLNB and ALND that are currently debated. Moreover, SLNB remains an unstandardized procedure surrounded by many unresolved controversies concerning the technique itself. In this article, we review the main indications, contraindications, and controversies of SLNB in breast cancer in the light of the most recent publications.

Ra alpha therapy is an important therapeutic option for men with CRPC and symptomatic skeletal metastases.

The role of nuclear medicine physicians in the multidisciplinary team for the management of patients with prostate cancer has been restricted because of a lack of available tools. The only drugs approved to relieve pain related to bone metastases were β-emitting radiopharmaceuticals. These drugs did not prove to prolong survival when used as single agent and resulted associated with important adverse events. This situation has changed with the introduction of radium 223 because of evidence of improved survival in patients, the good safety profile and the opportunity to avoid clonal selection of tumor cells. Cooperation among physicians involved in cancer management will lead to improvements in the treatment of bone metastases due to prostate cancer and is thought to extend to other tumor types. KeywordsThe management of most prostate cancer cases involves committed specialists such as urologists, medical oncologists, radiotherapists, and nuclear medicine physicians. Evidence shows that in men with high-risk prostate cancer, only a patient-focused program based on a multidisciplinary approach can result in improved survival [1]. The role of nuclear medicine physicians in this multidisciplinary team so far has been restricted to providing pain relief. In castration-resistant prostate cancer (CRPC) patients with bone metastases (mCRPC), radiopharmaceuticals turned out to be useful only for noncurative purposes, exclusively aiming at improving symptomatic pain control. In addition, the available drugs have induced considerable serious adverse events, mostly hematologic, and thus have prevented subsequent therapeutic approaches [2]. Therefore, radionuclide-based therapy for symptomatic bone metastases has remained underused and limited to the late phases of the disease [3].The lack of safe therapeutic approaches to extend survival in CRPC patients has been a challenge for nuclear medicine physicians accustomed to successfully treating other tumor types, such as thyroid tumors with radioiodine therapy, or treating hematologic malignancies with ibritumomab tiuxetan. The recent introduction of the radiopharmaceutical radium Ra 223 (Ra 223) dichloride represents a breakthrough because, for the first time, an impact of a radiopharmaceutical on survival of patients with bone metastases due to prostate cancer was demonstrated in a large Phase III trial [4]. This drug, in fact, received the category 1 recommendation as first-line and second-line option by National Comprehensive Cancer Network (NCCN) guideline similarly to chemotherapy [5], and thus the nuclear medicine physician assumed a key position in the current multidisciplinary team for the treatment of mCRPC. The team should evaluate which patients are suitable for Ra 223 dichloride without limiting access to patients in the terminal stages of the disease and should integrate the nuclear medicine physician into the team with the medical oncologist and surgeon. Future Oncol. (Epub ahead of print)

Evidence of cortical beta-amyloid (Aβ) load, assessed by Aβ positron emission tomography (Aβ-PET), is an established in vivo biomarker of Alzheimer’s disease (AD)-related pathophysiology. Qualitative assessment of Aβ-PET provides binary information; meanwhile semiquantitative approaches require a parcellation of PET image either manually or by placement of atlas-based volumes of interest. We supposed that a whole-brain approach with voxel-by-voxel standardized uptake value ratio (SUVr) parametric images may better elucidate the spatial trajectories of Aβ burden along the continuum of AD. Methods: We recruited 32 subjects with a diagnosis of probable AD dementia (ADD, n = 20) and mild cognitive impairment due to AD (MCI-AD, n = 12) according to the NIA-AA 2011 criteria. We also enrolled a control group of 6 cognitively healthy individuals (HCs) with preserved cognitive functions and negative Aβ-PET scan. The PET images were spatially normalized using the AV45 PET template in the MNI brain space. Subsequently, parametric SUVr images were calculated using the whole cerebellum as a reference region. A voxel-wise analysis of covariance was used to compare (between groups) the Αβ distribution pattern considering age as a nuisance covariate. Results: Both ADD and MCI-AD subjects showed a widespread increase in radiotracer uptake when compared with HC participants (p < 0.001, uncorrected). After applying a multiple comparison correction (p < 0.05, corrected), a relative large cluster of increased [¹⁸F]-flor­betapir uptake was observed in the precuneus in the ADD and MCI-AD groups compared to HCs. Voxel-wise regression analysis showed a significant positive linear association between the voxel-wise SUVr values and the disease duration. Conclusions: The voxel-wise semiquantitative analysis shows that the precuneus is a region with higher vulnerability to Aβ depositions when compared to other cortical regions in both MCI-AD and ADD subjects. We think that the precuneus is a promising PET-based outcome measure for clinical trials of drugs targeting brain Aβ. We found a positive association between the overall Aβ-PET SUVr and the disease duration suggesting that the region-specific slow saturation of Aβ deposition continuously takes place as the disease progresses.