Correlation between ferromagnetic and isotopic tracers for sentinel lymph node detection in cutaneous melanoma: IMINEM study

BACKGROUND

The usefulness of sentinel lymph node biopsy (SLNB) in staging cutaneous melanoma has been proven. Therefore, different tracers have been used to identify the sentinel lymph nodes (SLNs). The use of isotopic tracers together with radioactivity detectors allowed a much more precise and direct approach to the SLNs. However, not all centres have access to a Nuclear Medicine department hindering sentinel lymph node detection (SLND) and consequently, other markers such as ferromagnetic tracers have been evaluated looking for the same advantages and effectiveness as isotopic tracers. Ferromagnetic tracers have proven their usefulness in other cancer entities such as breast, prostate and thyroid cancer. The objective was to assess the detection and concordance rates between isotopic and ferromagnetic techniques for SLNB in cutaneous melanoma.

METHOD

Isotopic SLNB technique and ferromagnetic tracer were compared for cutaneous melanoma in a non-inferiority multicentre prospective study carried out in six Spanish hospitals.

RESULTS

A total of 60 patients were recruited and 133 lymph nodes removed. The detection rate was slightly higher with ferromagnetic tracer in head-neck and trunk melanomas, and with isotopic tracer in limbs. The patients' and nodes' concordance rates between both techniques for ex vivo samples were 95% and 86% for head-neck and trunk tumours and 97% and 93% for limbs tumours, respectively. The concordance rates for involved nodes were 100% and 88.2% for patients and nodes, respectively.

CONCLUSION

The intraoperative detection and biopsy of SLN in cutaneous melanoma using a ferromagnetic was a reliable alternative method to the isotopic technique in cutaneous melanomas.

Trending: Radioactive and Fluorescent Bimodal/Hybrid Tracers as Multiplexing Solutions for Surgical Guidance

By contributing to noninvasive molecular imaging and radioguided surgery, nuclear medicine has been instrumental in the realization of precision medicine. During the last decade, it has also become apparent that nuclear medicine (e.g., in the form of bimodal/hybrid tracers) can help to empower fluorescence-guided surgery. More specifically, when using hybrid tracers, lesions can be noninvasively identified and localized with a high sensitivity and precision (guided by the radioisotope) and ultimately resected under real-time optical guidance (fluorescent dye). This topical review discusses early clinical successes, preclinical directions, and key aspects that could have an impact on the future of this field.

Use of Radioactive Seed Localization to Guide Removal of a Nonpalpable Endometriotic Lesion: A Case Report

Extrapelvic endometriosis is a rare and usually misdiagnosed entity. Some extrapelvic endometriotic lesions are small and nonpalpable, which makes them difficult to locate and remove. Here, we report the use of radioactive seed localization to locate and guide the excision of a small, nonpalpable endometriotic lesion. A 32-year-old woman presented with disabling pain in the right inguinal area. Magnetic resonance imaging and abdominal ultrasound results showed an 11-mm nodule in the abdominal wall, in the vicinity of the groin, consistent with an endometriotic lesion. The radioactive seed was placed within the lesion with the help of ultrasonography, and excision was guided with a portable gamma camera. Complete excision of the endometriotic nodule was achieved. We propose radioactive seed localization as an accurate and feasible technique for the treatment of nonpalpable endometriotic lesions.

Next generation of radiotracers for sentinel lymph node biopsy: What is still necessary to establish new imaging paradigms?

Sentinel lymph node (SLN) biopsy is now the standard of care for regional staging in several solid tumors. The interstitial administration of a radiotracer around the primary tumor provide the possibility to sequentially obtain images with a gamma camera and visualize lymphatic mapping and the SLN. There is, however, a large geographical variability in those radiotracers and nanocolloids ranging from 15-100nm which are most widely employed in Europe, while filtered and unfiltered ^99mTc-sulfur colloid (range 20-1000nm) is usually used in the USA with different drawbacks in its use. The new radiotracer ^99mTc-Tilmanocept, designed specifically for the identification of SLNs and recently becoming commercially available in USA and Europe, appears to have the potency to overcome the shortcomings described for the conventional radiotracers used until now for SLN biopsy and at the same time to transform current imaging paradigms. After delineating the challenges for the next generation of radiotracers, this paper discusses the properties of ^99mTc-Tilmanocept, its validation process for SLN biopsy and its emerging clinical applications in various malignancies.

Cost-effectiveness analysis of imaging strategy for an intensive follow-up of patients with American Joint Committee on Cancer stage IIB, IIC and III malignant melanoma

BACKGROUND

Many follow-up guidelines for patients with high-risk melanoma include expensive imaging studies, serum biomarkers and regular visits to the dermatologist, with little attention to cost-effectiveness.

OBJECTIVES

To establish the cost-effectiveness of chest-abdomen-pelvis computed tomography (CT) and brain magnetic resonance imaging (MRI) in a follow-up protocol for patients at high risk of relapse.

METHODS

This was a prospective single-centre cohort study of 290 patients with clinicopathological American Joint Committee on Cancer (AJCC) stage IIB, IIC and III melanoma. Patients had a body CT scan and brain MRI every 6 months and were withdrawn from the study after completing a 5-year follow-up or when metastases were detected. A cost-effectiveness analysis for each follow-up radiological procedure was performed.

RESULTS

Patients underwent 1805 body CT scans and 1683 brain MRIs. Seventy-six metastases (26·2%) were identified by CT or MRI. CT scan was cost-effective in the first 4 years (cost-effectiveness ratio €4710·70-€14 437·10/patient with metastasis); brain MRI was cost-effective during the first year (cost-effectiveness ratio €14 090·60/patient with metastasis). Limitations included lack of survival analysis and comparisons with willingness-to-pay thresholds.

CONCLUSIONS

Six-monthly CT scan of the chest, abdomen and pelvis is a cost-effective technique for the early detection of metastases in the first 4 years of follow-up in patients with AJCC stage IIC and III melanoma, and in the first 3 years in patients with AJCC stage IIB melanoma. In addition, brain MRI has been shown to be cost-effective only in the first year of follow-up in patients with AJCC stage IIC and III melanoma.

Applicability of sentinel lymph node biopsy in papillary thyroid cancer

BACKGROUND

The optimal surgical management of papillary thyroid cancer (PTC) for T1-T2 tumors without pre or intrasurgical evidence of lymph node metastasis (cN0) remains controversial, since approximately 40% of patients have lymph node involvement (pN1) which becomes evident when a prophylactic lymphadenectomy (PL) is performed. The aim of this study was to investigate the feasibility of sentinel lymph node (SLN) identification with SPECT/CT lymphoscintigraphy imaging along with intraoperatory image techniques in early stages of PTC undergoing PL of central neck compartment (CNC).

METHODS

A single-center, prospective consecutive study was designed for SLN mapping in patients with high suspicion of PTC (Bethesda V or VI) in early stage (cT1-2, cN0). Twenty-four patients underwent SLN identification with preoperative SPECT/CT and planar images (^99mTc-nanocolloid albumin intratumoral injection). During surgery, SLN located in CNC was found by means of a gamma probe and portable gamma camera, and excised. Afterwards, CNC lymphadenectomy was performed in all cases without modifying the established protocol.

RESULTS

SLNs were identified and accurately located in 23 (95.8%) patients. Nodal metastases (pN1) were confirmed in 9 (37.5%) patients, with one false negative case. The sensitivity was 88.9% and negative predictive value (NPV) was 93.3%, would have allowed to avoid PL in more than half of cases, a higher proportion than those found in other similar studies. No complications associated with the procedure were observed.

CONCLUSIONS

Our results support that SLN biopsy by SPECT/CT along with intraoperatory image techniques is applicable in early stages of PTC (cT1-2, cN0), allowing to avoid unnecessary PL.

Melanoma & nuclear medicine: new insights & advances

The contribution of nuclear medicine to management of melanoma patients is increasing. In intermediate-thickness N0 melanomas, lymphoscintigraphy provides a roadmap for sentinel node biopsy. With the introduction of single-photon emission computed tomography images with integrated computed tomography (SPECT/CT), 3D anatomic environments for accurate surgical planning are now possible. Sentinel node identification in intricate anatomical areas (pelvic cavity, head/neck) has been improved using hybrid radioactive/fluorescent tracers, preoperative lymphoscintigraphy and SPECT/CT together with modern intraoperative portable imaging technologies for surgical navigation (free-hand SPECT, portable gamma cameras). Furthermore, PET/CT today provides 3D roadmaps to resect 18F-fluorodeoxyglucose-avid melanoma lesions. Simultaneously, in advanced-stage melanoma and recurrences, 18F-fluorodeoxyglucose-PET/CT is useful in clinical staging and treatment decision as well as in the evaluation of therapy response. In this article, we review new insights and recent nuclear medicine advances in the management of melanoma patients.

Selective Sentinel Lymph Node Biopsy and Primary Systemic Therapy in Breast Cancer

Aims and background

Sentinel lymph node biopsy has become an ordinary method for breast cancer staging. Neoadjuvant chemotherapy has been considered one of the contraindications for sentinel lymph node biopsy due to potential secondary fibrosis and lymphatic distortion. Timing and influence on sentinel lymph node biopsy result by primary systemic therapy are current and controversial topics.

Methods and study design

The experience in the medical literature is reviewed. A search was performed in the following databases: Medline (through Pubmed), EMBASE, Tripdatabase and Cochrane Library, between January 1998 and December 2008.

Results and conclusions

After analyzing the conclusions from 42 series and waiting for the end of related prospective trials, it could be concluded that sentinel lymph node biopsy is a useful diagnostic tool that should be integrated in the algorithm for the management of breast cancer patients when primary systemic therapy is needed.

Monitoring system for isolated limb perfusion based on a portable gamma camera

Background: The treatment of malignant melanoma or sarcomas on a limb using extremity perfusion with tumour necrosis factor (TNF-α) and melphalan can result in a high degree of systemic toxicity if there is any leakage from the isolated blood territory of the limb into the systemic vascular territory. Leakage is currently controlled by using radiotracers and heavy external probes in a procedure that requires continuous manual calculations. The aim of this work was to develop a light, easily transportable system to monitor limb perfusion leakage by controlling systemic blood pool radioactivity with a portable gamma camera adapted for intraoperative use as an external probe, and to initiate its application in the treatment of MM patients. Methods: A special collimator was built for maximal sensitivity. Software for acquisition and data processing in real time was developed. After testing the adequacy of the system, it was used to monitor limb perfusion leakage in 16 patients with malignant melanoma to be treated with perfusion of TNF-α and melphalan. Results: The field of view of the detector system was 13.8 cm, which is appropriate for the monitoring, since the area to be controlled was the precordial zone. The sensitivity of the system was 257 cps/MBq. When the percentage of leakage reaches 10% the associated absolute error is ± 1%. After a mean follow-up period of 12 months, no patients have shown any significant or lasting side-effects. Partial or complete remission of lesions was seen in 9 out of 16 patients (56%) after HILP with TNF-α and melphalan. Conclusion: The detector system together with specially developed software provides a suitable automatic continuous monitoring system of any leakage that may occur during limb perfusion. This technique has been successfully implemented in patients for whom perfusion with TNF-α and melphalan has been indicated.

From interventionist imaging to intraoperative guidance: New perspectives by combining advanced tools and navigation with radio-guided surgery

The integration of medical imaging technologies into diagnostic and therapeutic approaches can provide a preoperative insight into both anatomical (e.g. using computed tomography, magnetic resonance imaging, or ultrasound), as well as functional aspects (e.g. using single photon emission computed tomography, positron emission tomography, lymphoscintigraphy, or optical imaging). Moreover, some imaging modalities are also used in an interventional setting (e.g. computed tomography, ultrasound, gamma or optical imaging) where they provide the surgeon with real-time information during the procedure. Various tools and approaches for image-guided navigation in cancer surgery are becoming feasible today. With the development of new tracers and portable imaging devices, these advances will reinforce the role of interventional molecular imaging.

SPECT-CT and intraoperative portable gamma-camera detection protocol for sentinel lymph node biopsy in oral cavity squamous cell carcinoma

OBJECTIVE

The aim of this study was to evaluate a multimodality approach to sentinel lymph node biopsy (SLNB) detection with lymphoscintigraphy and single-photon emission computed tomography (SPECT)/computed tomography (CT). When combined with intraoperative imaging by a portable gamma camera (PGC), improved SLNB accuracy and detection rate may result.

MATERIAL AND METHODS

A total of 42 patients selected for SLNB in node-negative T1 and T2 oral squamous cell carcinoma were retrospectively analyzed. The detection protocol consisted of preoperative lymphoscintigraphy and SPECT/CT performed the day before surgery. Intraoperative sentinel lymph node (SLN) detection was done with the aid of a PGC in association with hand-held gamma probe.

RESULTS

All SLN detected in the preoperative study could be harvested except for one case. A total of 131 SLN were resected. This number was higher than the SLN depicted on lymphoscintigraphy (119 SLNs) and SPECT/CT (123 SLNs). Sublingual SLNs were observed in two cases (4.76%). These SLNs were detected by SPECT/CT but not by lymphoscintigraphy. Five (3.8%) additional SLNs not previously visualized on lymphoscintigraphy or on SPECT/CT were detected intraoperatively with the aid of the PGC. Positive SLNs were detected in eight cases (19%). Micrometastases were detected in five cases (62%) and macrometastases in three cases (38%).

CONCLUSION

The SLNB detection protocol described contributes to more accurate study and detection.

Prognostic role of the histological subtype of melanoma on the hands and feet in Caucasians

Acral melanoma (AM) is associated with a poor prognosis in part because of delayed diagnosis, but probably also because of other intrinsic characteristics of location. The aim of this study was to review the specific characteristics and outcome of AM in Caucasians. This was a cross-sectional retrospective clinical-pathological study of 274 patients identified with AM in the database of a referral unit in Europe from 1986 to 2010. The mean age of the patients was 56.6 (SD 17.7) years. 269 cases could be histologically classified and included in the study. In all, 222 (82.5%) were located on feet. According to melanoma subtype, 165 (61.3%) were acral lentiginous melanoma (ALM), 84 (31.2%) were superficial spreading melanoma (SSM), and 20 (7.5%) were nodular melanoma (NM). SSM patients were characterized by female predominance (77.4%), younger age, and classic melanoma-risk phenotype (fair skin and multiple nevi). Among the 198 invasive cases with a mean follow-up of 56.2 months, the mean (SD) Breslow's thickness was 3.1 (3.6) mm, being 1.4 (1.4) mm in SSM, 3.5 (4.1) mm in ALM and 4.9 (2.9) mm in NM (P<0.001). Ulceration was present in 33.3%, 2.9% in SSM, 38.6% in ALM, and 76.9% in NM (P<0.001). A total of 29.3% relapsed (7.3% of SSM, 35% of ALM and 55% of NM) and 24.2% died because of AM. In multivariate analysis, age at diagnosis, Breslow, and histopathological subtype were independent prognostic factors for both disease-free and AM-specific survival. The ALM and NM subtypes presented poorer outcome after weighting Breslow and age (P=0.02). Histological subtype of AM could have an impact on biological behavior, ALM and NM subtypes presenting a poorer prognosis after adjusting for age and Breslow's thickness.

Completion Dissection or Observation for Sentinel-Node Metastasis in Melanoma

BACKGROUND

Sentinel-lymph-node biopsy is associated with increased melanoma-specific survival (i.e., survival until death from melanoma) among patients with node-positive intermediate-thickness melanomas (1.2 to 3.5 mm). The value of completion lymph-node dissection for patients with sentinel-node metastases is not clear.

METHODS

In an international trial, we randomly assigned patients with sentinel-node metastases detected by means of standard pathological assessment or a multimarker molecular assay to immediate completion lymph-node dissection (dissection group) or nodal observation with ultrasonography (observation group). The primary end point was melanoma-specific survival. Secondary end points included disease-free survival and the cumulative rate of nonsentinel-node metastasis.

RESULTS

Immediate completion lymph-node dissection was not associated with increased melanoma-specific survival among 1934 patients with data that could be evaluated in an intention-to-treat analysis or among 1755 patients in the per-protocol analysis. In the per-protocol analysis, the mean (±SE) 3-year rate of melanoma-specific survival was similar in the dissection group and the observation group (86±1.3% and 86±1.2%, respectively; P=0.42 by the log-rank test) at a median follow-up of 43 months. The rate of disease-free survival was slightly higher in the dissection group than in the observation group (68±1.7% and 63±1.7%, respectively; P=0.05 by the log-rank test) at 3 years, based on an increased rate of disease control in the regional nodes at 3 years (92±1.0% vs. 77±1.5%; P<0.001 by the log-rank test); these results must be interpreted with caution. Nonsentinel-node metastases, identified in 11.5% of the patients in the dissection group, were a strong, independent prognostic factor for recurrence (hazard ratio, 1.78; P=0.005). Lymphedema was observed in 24.1% of the patients in the dissection group and in 6.3% of those in the observation group.

CONCLUSIONS

Immediate completion lymph-node dissection increased the rate of regional disease control and provided prognostic information but did not increase melanoma-specific survival among patients with melanoma and sentinel-node metastases. (Funded by the National Cancer Institute and others; MSLT-II ClinicalTrials.gov number, NCT00297895 .).

Multimodal approach in radioguided surgery in a case of multiple paraganglioma

The case involves a 34-year-old woman who underwent surgical removal of a retroperitoneal paraganglioma adjacent to the left kidney's lower pole, previously visualized by CT and MRI. The ¹²³I-MIBG scan was positive for this lesion and, in addition, another uptake was observed located caudally at the level of L5 and of smaller size and less intensity. The second lesion was not considered for surgical removal, due to its lack of morphological definition. One week after surgical intervention, the patient presented difficult-to-control high blood pressure. A second ¹²³I-MIBG scan was performed. The previously described second image was more intense in this study, and surgery was planned to remove it. A combination of techniques including freehand-SPECT and a portable hybrid gamma camera (with optical camera) were used pre-operatively to identify the location of the lesion. The combination of intra-operative laparoscopic gamma probe and portable hybrid gamma camera enabled the tumor to be located, excised, and its complete removal to be monitored. The histopathology analysis confirmed a second paraganglioma.

Advances in radioguided surgery in oncology

The sentinel lymph node (SLN) biopsy is probably the most well-known radioguided technique in surgical oncology. Today SLN biopsy reduces the morbidity associated with lymphadenectomy and increases the identification rate of occult lymphatic metastases by offering the pathologist the lymph nodes with the highest probability of containing metastatic cells. These advantages may result in a change in clinical management both in melanoma and breast cancer patients. The SLN evaluation by pathology currently implies tumor burden stratification for further prognostic information. The concept of SLN biopsy includes pre-surgical lymphoscintigraphy as a "roadmap" to guide the surgeon toward the SLNs and to localize unpredictable lymphatic drainage patterns. In addition to planar images, SPECT/CT improves SLN detection, especially in sites closer to the injection site, providing anatomic landmarks which are helpful in localizing SLNs in difficult to interpret studies. The use of intraoperative imaging devices allows a better surgical approach and SLN localization. Several studies report the value of such devices for excision of additional sentinel nodes and for monitoring the whole procedure. The combination of preoperative imaging and radioguided localization constitutes the basis for a whole spectrum of basic and advanced nuclear medicine procedures, which recently have been encompassed under the term "guided intraoperative scintigraphic tumor targeting" (GOSTT). Excepting SLN biopsy, GOSTT includes procedures based on the detection of target lesions with visible uptake of tumor-seeking radiotracers on SPECT/CT or PET/CT enabling their subsequent radioguided excisional biopsy for diagnostic of therapeutic purposes. The incorporation of new PET-tracers into nuclear medicine has reinforced this field delineating new strategies for radioguided excision. In cases with insufficient lesion uptake after systemic radiotracer administration, intralesional injection of a tracer without migration may enable subsequent excision of the targeted tissue. This approach has been helpful in non-palpable breast cancer and in solitary pulmonary nodules. The introduction of allied technologies like fluorescence constitutes a recent advance aimed to refine the search for SLNs and tracer-avid lesions in the operation theatre in combination with radioguidance.

Radioguided surgery and the GOSTT concept: From pre-operative image and intraoperative navigation to image-assisted excision

Radio-guided surgery has been developed for application in those disease scheduled for surgical management, particularly in areas of complex anatomy. This is based on the use of pre-operative scintigraphic planar, tomographic and fused SPECT/CT images, and the possibility of 3D reconstruction for the subsequent intraoperative locating of active lesions using handheld devices (detection probes, gamma cameras, etc.). New tracers and technologies have also been incorporated into these surgical procedures. The combination of visual and acoustic signals during the intraoperative procedure has become possible with new portable imaging modalities. In daily practice, the images offered by these techniques and devices combine perioperative nuclear medicine imaging with the superior resolution of additional optical guidance in the operating room. In many ways they provide real-time images, allowing accurate guidance during surgery, a reduction in the time required for tissue location and an anatomical environment for surgical recognition. All these approaches have been included in the concept known as (radio) Guided intraOperative Scintigraphic Tumour Targeting (GOSTT). This article offers a general view of different nuclear medicine and allied technologies used for several GOSTT procedures, and illustrates the crossing of technological frontiers in radio-guided surgery.

18F-FDG PET/CT and sentinel lymph node biopsy in the staging of patients with cervical and endometrial cancer. Role of dual-time-point imaging

OBJECTIVE

Definitive staging for cervical (CC) and endometrial cancer (EC) takes place once surgery is performed. The aim of this study was to evaluate the role of PET/CT in detecting lymphatic metastasis in patients with CC and EC using dual-time-point imaging (DPI), taking the histopathological results of sentinel lymph node (SLN) and lymphadenectomy as the reference.

MATERIAL AND METHODS

A prospective study was conducted on 17 patients with early CC, and 13 patients with high-risk EC. The patients had a pre-operative PET/CT, MRI, SLN detection, and lymphadenectomy, when indicated. PET/CT findings were compared with histopathological results.

RESULTS

In the pathology study, 4 patients with CC and 4 patients with EC had lymphatic metastasis. PET/CT showed hypermetabolic nodes in 1 patient with CC, and 5 with EC. Four of these had metastasis, one detected in the SLN biopsy. Four patients who had negative PET/CT had micrometastasis in the SLN biopsy, 1 patient with additional lymph nodes involvement. The overall patient-based sensitivity, specificity, positive and negative predictive values, and accuracy of PET/CT to detect lymphatic metastasis was 20.0%, 100.0%, 100.0%, 87.9%, and 88.2%, respectively, in CC, and 57.1%, 88.9%, 66.7%, 84.2% and 80.0%, respectively, in EC. DPI showed higher retention index in malignant than in inflammatory nodes, although no statistically significant differences were found.

CONCLUSIONS

PET/CT has low sensitivity in lymph node staging of CC and EC, owing to the lack of detection of micrometastasis. Thus, PET/CT cannot replace SLN biopsy. Although no statistically significant differences were found, DPI may help to differentiate between inflammatory and malignant nodes.

Performance of diagnostic tests in an intensive follow-up protocol for patients with American Joint Committee on Cancer (AJCC) stage IIB, IIC, and III localized primary melanoma: A prospective cohort study

BACKGROUND

There is no international consensus on optimal follow-up schedules and which supplementary tests should be used after resection of a primary melanoma.

OBJECTIVE

We sought to analyze the performance of the follow-up components and identify procedures that detect melanoma metastasis earlier.

METHODS

This was a prospective cohort from 290 consecutive patients given a diagnosis of stage IIB, IIC, and III melanoma. Patients were followed up with an intensive protocol based on imaging studies (computed tomography of the chest, abdomen, and pelvis, and brain magnetic resonance imaging), periodic laboratory tests, regular physical examinations, and patient self-examinations.

RESULTS

A total of 2382 clinical examinations and 3069 imaging tests were performed. The patients completed 899.8 person-years of follow-up, with a median of 2.5 years. In all, 115 recurrences in 290 patients were recorded, of which computed tomography detected 48.3%; brain magnetic resonance imaging, 7.6%; laboratory test, 2.5%; physician, 23.7%; and patient, 17.8%.

LIMITATIONS

Patients with stage III melanoma were not systematically classified into subgroups and overall survival was not evaluated.

CONCLUSION

We observed that this intensive monitoring is appropriate for early detection of recurrence in stage IIB, IIC, and III melanoma. Prompt diagnosis of metastasis and the recent development of new therapeutic targets may improve overall survival.

Hybrid surgical guidance based on the integration of radionuclear and optical technologies

With the evolution of imaging technologies and tracers, the applications for nuclear molecular imaging are growing rapidly. For example, nuclear medicine is increasingly being used to guide surgical resections in complex anatomical locations. Here, a future workflow is envisioned that uses a combination of pre-operative diagnostics, navigation and intraoperative guidance. Radioguidance can provide means for pre-operative and intraoperative identification of "hot" lesions, forming the basis of a virtual data set that can be used for navigation. Luminescence guidance has shown great potential in the intraoperative setting by providing optical feedback, in some cases even in real time. Both of these techniques have distinct drawbacks, which include inaccuracy in areas that contain a background signal (radioactivity) or a limited degree of signal penetration (luminescence). We, and others, have reasoned that hybrid/multimodal approaches that integrate the use of these complementary modalities may help overcome their individual weaknesses. Ultimately, this will lead to advancement of the field of interventional molecular imaging/image-guided surgery. In this review, an overview of clinically applied hybrid surgical guidance technologies is given, whereby the focus is placed on tracers and hardware.

Usefulness of (18)F-FDG PET/CT in recurrent basal cell carcinoma: Report of a case

We analyze the case of a patient with left periorbital infiltrating basal cell carcinoma treated with surgical excision in October 2010. Surgery included orbital exenteration and reconstruction using skin graft and radiotherapy. In May 2013 a MR imaging showed a mass in the left orbital fossa, suggesting a recurrence in the graft. A basal cell carcinoma recurrence with perineural invasion was confirmed in the biopsy. On (18)F-FDG PET/CT performed, a hypermetabolic activity was observed in the left periorbital area with extension to surrounding sinus and bones. The use of (18)F-FDG PET/CT in patients with advanced basal cell carcinoma has not been fully explored due to the rarity of this entity. This case demonstrates the usefulness of this technique to determine the extent of non-melanocytic recurrent skin tumors, and its value in the staging and treatment control, supporting the incorporation of (18)F-FDG PET/CT in the management of advanced basal cell carcinoma.

Sentinel node approach in prostate cancer

In general terms, one of the main objectives of sentinel lymph node (SLN) biopsy is to identify the 20-25% of patients with occult regional metastatic involvement. This technique reduces the associated morbidity from lymphadenectomy, as well as increasing the identification rate of occult lymphatic metastases by offering the pathologist those lymph nodes with the highest probability of containing metastatic cells. Pre-surgical lymphoscintigraphy is considered a "road map" to guide the surgeon towards the sentinel nodes and to ascertain unpredictable lymphatic drainages. In prostate cancer this aspect is essential due to the multidirectional character of the lymphatic drainage in the pelvis. In this context the inclusion of SPECT/CT should be mandatory in order to improve the SLN detection rate, to clarify the location when SLNs are difficult to interpret on planar images, to achieve a better definition of them in locations close to injection site, and to provide anatomical landmarks to be recognized during operation to locate SLNs. Conventional and laparoscopic hand-held gamma probes allow the SLN technique to be applied in any kind of surgery. The introduction and combination of new tracers and devices refines this technique, and the use of intraoperative images. These aspects become of vital importance due to the recent incorporation of robot-assisted procedures for SLN biopsy. In spite of these advances various aspects of SLN biopsy in prostate cancer patients still need to be discussed, and therefore their clinical application is not widely used.

Effect of time to sentinel-node biopsy on the prognosis of cutaneous melanoma

INTRODUCTION

In patients with primary cutaneous melanoma, there is generally a delay between excisional biopsy of the primary tumour and sentinel-node biopsy. The objective of this study is to analyse the prognostic implications of this delay.

PATIENTS AND METHOD

This was an observational, retrospective, cohort study in four tertiary referral hospitals. A total of 1963 patients were included. The factor of interest was the interval between the date of the excisional biopsy of the primary melanoma and the date of the sentinel-node biopsy (delay time) in the prognosis. The primary outcome was melanoma-specific survival and disease-free survival.

RESULTS

A delay time of 40 days or less (hazard ratio (HR), 1.7; confidence interval (CI), 1.2-2.5) increased Breslow thickness (Breslow ⩾ 2 mm, HR, > 3.7; CI, 1.4-10.7), ulceration (HR, 1.6; CI, 1.1-2.3), sentinel-node metastasis (HR, 2.9; CI, 1.9-4.2), and primary melanoma localised in the head or neck were independently associated with worse melanoma-specific survival (all P < 0.03). The stratified analysis showed that the effect of delay time was at the expense of the patients with a negative sentinel-node biopsy and without regression.

CONCLUSION

Early sentinel-node biopsy is associated with worse survival in patients with cutaneous melanoma.

Dermoscopy structures as predictors of sentinel lymph node positivity in cutaneous melanoma

BACKGROUND

Histological features such as Breslow thickness, ulceration and mitosis are the main criteria to guide sentinel lymph node biopsy (SLNB) in melanoma. Dermoscopy may add complementary information to these criteria.

OBJECTIVES

To evaluate the correlation between dermoscopy structures and SLNB positivity.

METHODS

Retrospective analysis of 123 consecutive melanomas with Breslow thickness > 0·75 mm, SLNB performed during follow-up and dermoscopic images.

RESULTS

Men were more likely to have a positive SLNB. The presence of ulceration and blotch and the absence of a pigmented network in dermoscopy correlated with positive SLNB. Histological ulceration also correlated with positive SLNB. A dermoscopy SCORE predicted SLN status with a sensitivity of 96·3% and a specificity of 30·2%. When sex and Breslow thickness were added (SCOREBRESEX), the sensitivity remained at 96·3% but the specificity increased to 52·1%. This study is limited by the number of patients and was performed in only one institution.

CONCLUSIONS

Dermoscopy allowed a more precise prediction of SLN status. If a combined SCOREBRESEX was used to select patients for SLNB, 41·5% of procedures might be avoided.

The next evolution in radioguided surgery: breast cancer related sentinel node localization using a freehandSPECT-mobile gamma camera combination

Accurate pre- and intraoperative identification of the sentinel node (SN) forms the basis of the SN biopsy procedure. Gamma tracing technologies such as a gamma probe (GP), a 2D mobile gamma camera (MGC) or 3D freehandSPECT (FHS) can be used to provide the surgeon with radioguidance to the SN(s). We reasoned that integrated use of these technologies results in the generation of a "hybrid" modality that combines the best that the individual radioguidance technologies have to offer. The sensitivity and resolvability of both 2D-MGC and 3D-FHS-MGC were studied in a phantom setup (at various source-detector depths and using varying injection site-to-SN distances), and in ten breast cancer patients scheduled for SN biopsy. Acquired 3D-FHS-MGC images were overlaid with the position of the phantom/patient. This augmented-reality overview image was then used for navigation to the hotspot/SN in virtual-reality using the GP. Obtained results were compared to conventional gamma camera lymphoscintigrams. Resolution of 3D-FHS-MGC allowed identification of the SNs at a minimum injection site (100 MBq)-to-node (1 MBq; 1%) distance of 20 mm, up to a source-detector depth of 36 mm in 2D-MGC and up to 24 mm in 3D-FHS-MGC. A clinically relevant dose of approximately 1 MBq was clearly detectable up to a depth of 60 mm in 2D-MGC and 48 mm in 3D-FHS-MGC. In all ten patients at least one SN was visualized on the lymphoscintigrams with a total of 12 SNs visualized. 3D-FHS-MGC identified 11 of 12 SNs and allowed navigation to all these visualized SNs; in one patient with two axillary SNs located closely to each other (11 mm), 3D-FHS-MGC was not able to distinguish the two SNs. In conclusion, high sensitivity detection of SNs at an injection site-to-node distance of 20 mm-and-up was possible using 3D-FHS-MGC. In patients, 3D-FHS-MGC showed highly reproducible images as compared to the conventional lymphoscintigrams.

[Presence of intramammary lymph nodes in the preoperative lymphoscintigraphy to locate the sentinel lymph node. Clinical significance]

OBJECTIVE

The routes of lymphatic drainage from a breast cancer are the axilla (the most frequent) and the extra axillary regions. Among the latter, there are the so-called intrammamary lymph nodes (IMLN). This study has aimed to assess the incidence of IMLNs in our patients and study the evolution of these cases with IMLN in the lymphoscintigraphy.

MATERIAL AND METHODS

Thirty-eight patients (out of 1725) with IMLN in the pre-operative lymphoscintigraphy were assessed. During the surgical procedure, using a gamma probe, IMLNs were located and excised. After their harvesting, a meticulous surgical field scan was performed. When the axillary sentinel node was positive for metastasis, a complete axillary lymphadenectomy was performed. In those where the axillary sentinel node was negative and IMLN was positive (IMLN+), axillary lymphadenectomy was also performed, except for one case.

RESULTS

Thirty-four out of the 38 IMLNs were obtained (89.5%), because no lymphatic tissue was found in pathology analysis in three cases (8%) and in one patient (3%) IMLN was not found during surgery. Ten (26%) metastatic IMLNs were located and the remaining 24 IMLNs cases (63%) were metastasis-free. During the clinical follow-up, one patient with IMLN+ developed hepatic metastases. The remaining 33 patients did not present any recurrence. No follow-up data were available for three patients.

CONCLUSIONS

IMLN and axillary sentinel node biopsy are recommended when both are depicted in preoperative lymphoscintigraphy. The axilla treatment will only depend on the axillary sentinel node status. Based on the data from other authors and our own experience, avoiding the axillary lymphadenectomy when a metastatic IMLN without axillary involvement seems reasonable.

Melanoma and nuclear medicine

Supported by a large body of published work, the contribution of nuclear medicine technologies to the assessment of melanoma has been increasing in recent years. Lymphoscintigraphy-assisted sentinel lymph node biopsy and PET are in continuous evolution with the aid of technological imaging advances, making it possible to fuse functional and anatomic images (e.g., with SPECT/CT, PET/CT and 3D rendering systems). The development of hybrid fluorescent-radioactive tracers that enable high-quality preoperative lymphoscintigraphy and SPECT/CT, and the optimization of modern intraoperative portable imaging technologies, such as free-hand SPECT and portable γ-cameras, are important innovations that have improved sentinel lymph node identification in complex anatomical areas, such as the pelvis and head and neck. Concurrently, ¹⁸F-fluorodeoxyglucose-PET has proved its usefulness in the clinical staging and treatment decision-making process, and there is also emerging evidence regarding its utility in the evaluation of therapeutic response. The potential uses of other novel PET radiotracers could open up a new field of use for this technique. In this article, we review the current and future role of nuclear medicine in the management of melanoma.

[Radioguided surgery in neuroendocrine tumors. A review of the literature]

Radioguided surgery can be a useful technique in the localization of neuroendocrine tumors. It detects more and smaller lesions compared to pre-surgical imaging and intraoperative digital palpation by the surgeon. It detects residual lesions and also indicates the shortest access route to the lesion. Nevertheless, its use has not become widespread because of technical difficulties. There is a limited number of published series, a lack of standardized protocol because of the great variability regarding type of radiopharmaceutical, dose of radiotracer, timing between injection and surgery. In this paper, we review these issues, describing the experience of different authors in diverse tumors.

[Bone defects in revision knee arthroplasty: filling with bone allograft plus platelet-derived growth factors]

BACKGROUND

One of the most challenging aspects of a revision knee arthroplasty is the management of bone loss. The OBJECTIVE of the study is to show the capability to augment bone mineral density in areas with bone loss with platelet-derived growth factors.

METHODS

Randomized, prospective, blinded study in patients who underwent a total knee replacement revision with tibial-damaged metaphyseal bone were randomly allocated to have a revision total knee arthroplasty and to fill the bone defects with lyophilized bone allograft mixed with platelet growth factors (experimental group, n= 9) or with lyophilized bone allograft alone (control group, n= 7). To evaluate bone mineral density between groups, dual-energy X-ray absorptiometry (DEXA) was performed preoperatively, at 1 month, 6 months and 1 year after surgery.

RESULTS

The study was comprised of a total of 16 patients. We found no significant differences observed during the follow-up between groups in mineral bone density.

CONCLUSIONS

Use of platelet-derived growth factors does not improve bone mineral density in patients with revision knee arthroplasty.

Contribution of SPECT/CT imaging to radioguided sentinel lymph node biopsy in breast cancer, melanoma, and other solid cancers: from "open and see" to "see and open"

A few years ago SPECT/CT was successfully incorporated into the sentinel node (SN) procedure for breast cancer and melanoma. Important contributions of SPECT/CT in these two malignancies were the anatomical localization of SNs already visualized on planar images, the detection of additional SNs in aberrant basins, and the depiction of SNs in cases with no visualization on planar images. Recently, in a large series of melanoma patients the use of SPECT/CT was associated with the detection of more metastatic SNs and a higher rate of disease-free survival. Following the experiences in breast cancer and melanoma, SPECT/CT has been applied in oral cavity cancer as well as in urological and gynaecological malignancies. In the areas of lymphatic drainage of these malignancies (head and neck, pelvis, and upper abdomen) SPECT/CT appears to be essential to localize SNs, providing surgeons with helpful anatomical landmarks to plan SN biopsies. In gastrointestinal and lung malignancies SPECT/CT has only incidentally been used. With the improvement of the CT component in the second generation of SPECT/CT gamma cameras, nuclear physicians today can identify lymph nodes corresponding with the radioactive SNs. This is possible using a display of SPECT/CT similar to that of conventional tomography. Multiplanar reconstruction enables to correlate radioactive sentinel nodes seen on fused SPECT/CT with lymph nodes seen on CT, and the use of cross-reference lines allows the navigation between axial, coronal and sagittal views. This visual information is helpful for the intraoperative procedure and for post-excision assessment using portable devices. Fused SPECT/CT images may also be three-dimensionally displayed, improving anatomical SN localisation and recognition. This recent imaging improvement is leading to a new paradigm of "see and open" in contraposition to the former "open and see" in the SN procedure. The new mixed reality protocols which are able to transfer SPECT/CT to the operating room for surgical navigation will reinforce this "see and open" concept. However, a comprehensive interpretation of SPECT/CT together with lymphoscintigraphy is necessary to identify radioactive lymph nodes as sentinel nodes and classify them into different categories that are important for the intraoperative procedure.