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.

First Clinical Experience Using Stereotactic Breast Biopsy Guided by 99mTc-Sestamibi.

OBJECTIVE: The purpose of this study is to evaluate a new device using molecular breast imaging (MBI) for 99mTc-sestamibi-guided stereotactic lesion localization as a complementary biopsy tool. MATERIALS AND METHODS: From December 2012 to May 2016, a total of 38 consecutive women (mean age, 59 years; range, 41-77 years) underwent 99mTc-sestamibi-guided biopsy using a new MBI-based device and were retrospectively reviewed. The biopsy modality used five steps: stereotactic localization of the 99mTc-sestamibi-avid lesion, calculation of coordinates of the lesion location using dedicated software, placement of the needle, verification of the correct needle position, and tissue sampling with a vacuum-assisted device followed by placement of a radiologic marker at the biopsy site and ex vivo measurement of the biopsy specimens. RESULTS: The procedure was technically successful in all 38 lesions. In all cases, biopsy samples were radioactive and adequate for histopathologic analysis. Nineteen lesions (50%) were found to be malignant, and the remaining lesions were found to be benign. The mean procedure time was 71 minutes (range, 44-112 minutes). The radiologic marker was successfully deployed in 37 lesions (97%). Two hematomas and three vasovagal reactions were observed. CONCLUSION: Technetium-99m sestamibi-guided biopsy performed using a dedicated MBI-based device is technically feasible and represents a valuable complementary biopsy tool in breast lesion diagnosis.

Fluorescence guided surgery and tracer-dose, fact or fiction?

INTRODUCTION: Fluorescence guidance is an upcoming methodology to improve surgical accuracy. Challenging herein is the identification of the minimum dose at which the tracer can be detected with a clinical-grade fluorescence camera. Using a hybrid tracer such as indocyanine green (ICG)-(99m)Tc-nanocolloid, it has become possible to determine the accumulation of tracer and correlate this to intraoperative fluorescence-based identification rates. In the current study, we determined the lower detection limit of tracer at which intraoperative fluorescence guidance was still feasible. METHODS: Size exclusion chromatography (SEC) provided a laboratory set-up to analyze the chemical content and to simulate the migratory behavior of ICG-nanocolloid in tissue. Tracer accumulation and intraoperative fluorescence detection findings were derived from a retrospective analysis of 20 head-and-neck melanoma patients, 40 penile and 20 prostate cancer patients scheduled for sentinel node (SN) biopsy using ICG-(99m)Tc-nanocolloid. In these patients, following tracer injection, single photon emission computed tomography fused with computed tomography (SPECT/CT) was used to identify the SN(s). The percentage injected dose (% ID), the amount of ICG (in nmol), and the concentration of ICG in the SNs (in µM) was assessed for SNs detected on SPECT/CT and correlated with the intraoperative fluorescence imaging findings. RESULTS: SEC determined that in the hybrid tracer formulation, 41 % (standard deviation: 12 %) of ICG was present in nanocolloid-bound form. In the SNs detected using fluorescence guidance a median of 0.88 % ID was present, compared to a median of 0.25 % ID in the non-fluorescent SNs (p-value < 0.001). The % ID values could be correlated to the amount ICG in a SN (range: 0.003-10.8 nmol) and the concentration of ICG in a SN (range: 0.006-64.6 µM). DISCUSSION: The ability to provide intraoperative fluorescence guidance is dependent on the amount and concentration of the fluorescent dye accumulated in the lesion(s) of interest. Our findings indicate that intraoperative fluorescence detection with ICG is possible above a µM concentration.

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.

Detecting near-the-injection-site sentinel nodes in head and neck melanomas with a high-resolution portable gamma camera.

BACKGROUND: In head/neck melanomas, near-the-injection-site sentinel nodes (NIS-SNs) may be missed on planar lymphoscintigraphy and/or SPECT/CT. The aim of the present study is to establish the performance of a portable gamma camera (PGC) to detect NIS-SNs in a simulation phantom set-up, and subsequently in head/neck melanoma patients scheduled for a SN procedure. METHODS: Five plastic Eppendorf tubes filled with technetium-99m-albumin nanocolloid were used to simulate 4 radiotracer deposit sites, as traditionally injected in melanoma patients, and 1 NIS-SN. A PGC was used with 2 pinhole collimators (2.5 and 4.0 mm). Image acquisition time was 1 minute with the camera positioned at various distances (range 1.5-15.5 cm). Results were compared with conventional lymphoscintigraphy and SPECT/CT acquired with a dual-head gamma camera as well with a gamma probe. Additionally, the same PGC setting was used in a case series of 3 patients with head/neck melanomas. RESULTS: The simulated NIS-SN was differentiated from the injection site at a distance of 3 mm with the 2.5-mm pinhole and at 5 mm with the 4-mm pinhole when the PGC was positioned at 1.5 cm distance. Planar lymphoscintigraphy, SPECT/CT, and the gamma probe depicted the NIS-SN separated from the injection site at distances of 7, 10, and 22 mm, respectively. In all 3 patients, 6 NIS-SNs were depicted with the PGC. CONCLUSION: A high-resolution PGC, positioned close to the skin, is able to detect SNs at distances of at least 3 mm from the injection site. A further clinical evaluation of this device to establish its added value in reducing false-negative procedures and potential recurrences is necessary.

Practice variation in defining sentinel lymph nodes on lymphoscintigrams in oral cancer patients.

PURPOSE: Lymphoscintigraphic imaging and adequate interpretation of the lymphatic drainage pattern is an essential step in the sentinel lymph node biopsy (SLNB) procedure. In oral cancer, identification of the sentinel lymph node (SLN) can be challenging. In this study, interobserver variability in defining SLNs on lymphoscintigrams was evaluated in patients with T1-T2 stage N0 oral cancer. METHODS: Sixteen observers (head and neck surgeons, nuclear medicine physicians or teams of both) from various institutes were asked which criteria they use to consider a hot focus on the lymphoscintigram as SLN. Lymphoscintigrams of 9 patients with 47 hot foci (3-9 per patient) were assessed, using a scale of 'yes/equivocal/no'. Bilateral drainage was seen in four of nine cases. In three cases additional late single photon emission computed tomography (SPECT)/CT scanning was performed. Interobserver variability was evaluated by kappa (к) analysis, using linear weighted pairwise comparison of the observers. Conservative (equivocal analysed as no) and sensitive (equivocal analysed as yes) assessment strategies were investigated using pairwise kappa analysis. RESULTS: Various definitions of SLN on lymphoscintigrams were given. Interobserver variability of all cases using a 3-point scale showed fair agreement (71%, к(w) = 0.29). The conservative and sensitive analyses both showed moderate agreement: conservative approach к = 0.44 (in 80% of the hot foci the observers agreed) and sensitive approach к = 0.42 (81%) respectively. Multidisciplinary involvement in image interpretation and higher levels of observer experience appeared to increase agreement. CONCLUSION: Among 16 observers, there is practice variation in defining SLNs on lymphoscintigrams in oral cancer patients. Interobserver variability of lymphoscintigraphic interpretation shows moderate agreement. In order to achieve better agreement in defining SLNs on lymphoscintigrams specific guidelines are warranted.

Feasibility of preoperative (125)I seed-guided tumoural tracer injection using freehand SPECT for sentinel lymph node mapping in non-palpable breast cancer.

BACKGROUND: This study was designed to explore the feasibility of replacing the conventional peri-/intratumoural ultrasound (US)-guided technetium-99m albumin nanocolloid ((99m)Tc-nanocolloid) administration by an injection of the same tracer guided by a freehand single-photon emission computed tomography (SPECT) device in patients with non-palpable breast cancer with an iodine-125 ((125)I) seed as tumour marker, who are scheduled for a sentinel lymph node biopsy (SLNB). This approach aimed to decrease the workload of the radiology department, avoiding a second US-guided procedure. METHODS: In ten patients, the implanted (125)I seed was primarily localised using freehand SPECT and subsequently verified by conventional US in order to inject the (99m)Tc-nanocolloid. The following 34 patients were injected using only freehand SPECT localisation. In these patients, additional SPECT/CT was acquired to measure the distance between the (99m)Tc-nanocolloid injection depot and the (125)I seed. In retrospect, a group of 21 patients with US-guided (99m)Tc-nanocolloid administrations was included as a control group. RESULTS: The depth difference measured by US and freehand SPECT in ten patients was 1.6 ± 1.6 mm. In the following 36 (125)I seeds (34 patients), the average difference between the (125)I seed and the centre of the (99m)Tc-nanocolloid injection depot was 10.9 ± 6.8 mm. In the retrospective study, the average distance between the (125)I seed and the centre of the (99m)Tc-nanocolloid injection depot as measured in SPECT/CT was 9.7 ± 6.5 mm and was not significantly different compared to the freehand SPECT-guided group (two-sample Student's t test, p = 0.52). CONCLUSION: We conclude that using freehand SPECT for (99m)Tc-nanocolloid administration in patients with non-palpable breast cancer with previously implanted (125)I seed is feasible. This technique may improve daily clinical logistics, reducing the workload of the radiology department.

Lymphatic drainage from renal cell carcinoma along the thoracic duct visualized with SPECT/CT.

BACKGROUND: Lymphatic drainage of renal cell carcinoma is unpredictable. Renal lymphatics directly joining the thoracic duct without traversing any lymph nodes have been described in cadaver studies, yet to date, this has never been visualized using functional imaging in vivo. METHODS AND RESULTS: Patients with renal tumors <10 cm (cT1-cT2) and clinical absence of metastases (cN0, cM0) took part in a prospective institutional review board approved study investigating sentinel node mapping. After ultrasound-guided percutaneaus intratumoral injection of (99m)Tc-nanocolloid (0.4 mL, 200 MBq) the day before surgery, planar sequential lymphoscintigraphy was obtained after 20 min and 2-4 h. Subsequently, SPECT/CT imaging was performed. Of 42 patients, 4 showed early lymphatic drainage following the course of the thoracic duct on lymphoscintigraphy and SPECT/CT images. In one patient, this was observed without any retroperitoneal lymph node interposition. In relation to patients with sentinel nodes on SPECT imaging the frequency of this drainage pattern was (4/22) 18.2%. CONCLUSIONS: SN mapping of renal tumors using functional imaging modalities such as lymphoscintigraphy and SPECT/CT enables identification and sampling of sentinel nodes outside the area of routine dissection. Direct aberrant drainage through the thoracic duct can be observed in vivo as demonstrated in this study. This may support a hypothesis for certain anatomical metastatic sites and the failure to demonstrate a survival benefit of retroperitoneal lymph node dissections in renal cell carcinoma.

The additional value of lymphatic mapping with routine SPECT/CT in unselected patients with clinically localized melanoma.

PURPOSE: To investigate whether single photon emission computed tomography camera with integrated radiographic computed tomography (SPECT/CT) is of additional value compared to conventional lymphoscintigraphy in routine lymphatic mapping in patients with melanoma. METHODS: Thirty-five unselected patients with a primary melanoma who were scheduled for wide local excision and sentinel node biopsy underwent conventional lymphoscintigraphy and subsequently SPECT/CT. We determined whether SPECT/CT showed additional sentinel nodes, whether it provided better information on the location of the sentinel nodes, and whether this additional anatomic information led to a change in the planned surgical approach. RESULTS: SPECT/CT depicted the same 69 sentinel nodes as conventional lymphoscintigraphy in all 35 patients plus found eight additional sentinel nodes in seven patients (20%). In two of these patients (5.7%), an additional nodal basin had to be explored to find the extra sentinel nodes. SPECT/CT provided additional anatomic information that was helpful to the surgeon in 11 patients (31%) and led to an adjustment of the surgical approach in 10 patients (29%). CONCLUSIONS: SPECT/CT provided relevant additional information in 16 (46%) of the 35 patients. Routine use of SPECT/CT in addition to conventional lymphoscintigraphy is recommended in melanoma patients undergoing lymphatic mapping.

Less false-negative sentinel node procedures in melanoma patients with experience and proper collaboration.

BACKGROUND AND OBJECTIVES: The aims of the study were to determine the percentage of false-negative sentinel node procedures in melanoma patients, to investigate the time cohort of these recurrences, whether a learning phase was involved and to search for causes of the failures. METHODS: Between December 1993 and December 2008, 708 melanoma patients underwent a sentinel node biopsy. The procedure was considered false-negative if a recurrence developed in the basin from which a tumor-free sentinel node had been removed. Of all false-negative cases, the pre-operative images, operative report and pathology slides were reviewed. RESULTS: Sentinel node biopsy was positive in 164 (23%) of the patients and false-negative in 10 (1.4%), which results in a false-negative rate of 5.7%. Five of the 10 failures occurred in the first year after the sentinel node biopsy was introduced. Causes for these false-negative procedures could be attributed once to the nuclear medicine physician, once to the surgeon and twice to the pathologist. CONCLUSION: The sentinel node procedure failed to identify involvement in 5.7% of the patients with lymph node metastases. Half of the false-negative biopsies took place in the first year after the procedure was introduced, illustrating the existence of a learning period.

Detection of extra-axillary lymph node involvement with FDG PET/CT in patients with stage II-III breast cancer.

PURPOSE: The aim of this prospective study was to assess the incidence of extra-axillary lymph node involvement on baseline FDG PET/CT in patients with stage II-III breast cancer scheduled for neo-adjuvant chemotherapy. METHODS: Patients with invasive breast cancer of >3 cm and/or proven axillary lymph node metastasis were included for before neo-adjuvant chemotherapy. Baseline ultrasound of the infra- and supraclavicular regions was performed with fine-needle biopsy as needed. Subsequently FDG PET/CT was performed. All visually FDG-positive nodes were regarded as metastatic based on the previously reported high specificity of the technique. RESULTS: Sixty patients were included. In 17 patients (28%) extra-axillary lymph nodes were detected by FDG PET/CT, localised in an intra-mammary node (1 lymph node in 1 patient), mediastinal (2 lymph nodes in 2 patients), internal mammary chain (9 lymph nodes in 8 patients), intra- and interpectoral (6 lymph nodes in 4 patients), infraclavicular (5 lymph nodes in 4 patients) and in the contralateral axilla (3 lymph nodes in 2 patients). Ultrasound-guided cytology had detected extra-axillary lymph node involvement in seven of these patients, but was unable to detect extra-axillary nodes in the other 10 patients with positive extra-axillary lymph nodes on FDG PET/CT. Radiotherapy treatment was altered in 7 patients with extra-axillary involvement (12% of the total group). CONCLUSIONS: FDG PET/CT detected extra-axillary lymph node involvement in almost one-third of the patients with stage II-III breast cancer, including regions not evaluable with ultrasound. FDG PET/CT may be useful as an additional imaging tool to assess extra-axillary lymph node metastasis, with an impact on the adjuvant radiotherapy management.

Is 18F-FDG PET/CT useful for the early prediction of histopathologic response to neoadjuvant erlotinib in patients with non-small cell lung cancer?

UNLABELLED: Early prediction of treatment response is of value in avoiding the unnecessary toxicity of ineffective treatment. The objective of this study was to prospectively evaluate the role of integrated (18)F-FDG PET/CT for the early identification of response to neoadjuvant erlotinib, an epidermal growth factor receptor tyrosine kinase inhibitor. METHODS: From October 2006 to March 2009, 23 patients with non-small cell lung cancer eligible for surgical resection were evaluated for this study. Patients received preoperative erlotinib (150 mg) once daily for 3 wk. (18)F-FDG PET/CT was performed before and at 1 wk after the administration of erlotinib. Changes in tumor (18)F-FDG uptake during treatment were measured by standardized uptake values and assessed prospectively according to the criteria of the European Organization for Research and Treatment of Cancer. Patients with a decrease in standardized uptake values of 25% or more after 1 wk were classified as "metabolic responders." The metabolic response was compared with the pathologic response, obtained by histopathologic examination of the resected specimen. RESULTS: Following the (18)F-FDG PET/CT criteria of the European Organization for Research and Treatment of Cancer, 6 patients (26%) had a partial response within 1 wk, 16 patients (70%) had stable disease, and 1 patient (4%) had progressive disease. The median percentage of necrosis in the early metabolic responder group was 70% (interquartile range, 30%-91%), and the median percentage of necrosis in the nonresponder group was 40% (interquartile range, 20%-50%; P = 0.09). The kappa-agreement between the metabolic and pathologic responders was 0.55 (P = 0.008). CONCLUSION: The results of this study suggest that early during the course of epidermal growth factor receptor tyrosine kinase inhibitor therapy, (18)F-FDG PET/CT can predict response to erlotinib treatment in patients with non-small cell lung cancer.

Feasibility of FDG PET/CT to monitor the response of axillary lymph node metastases to neoadjuvant chemotherapy in breast cancer patients.

PURPOSE: The aim of this study was to assess the accuracy of (18)F-fluorodeoxyglucose (FDG) positron emission tomography (PET)/CT to visualize lymph node metastases before the start of neoadjuvant chemotherapy and to determine how often the visualization is sufficiently prominent to allow monitoring of the axillary response. METHODS: Thirty-eight patients with invasive breast cancer of >3 cm and/or lymph node metastasis underwent FDG PET/CT before neoadjuvant chemotherapy. The results of the FDG PET/CT were compared with those from ultrasonography with fine-needle aspiration (FNA) cytology or sentinel node biopsy. Patients suitable for response monitoring of the axilla were defined as having either a maximum standardized uptake value (SUV(max)) >or= 2.5 or a tumour to background ratio >or=5 in the most intense lymph node. RESULTS: The sensitivity and specificity of FDG PET/CT in detecting axillary involvement were 97 and 100%, respectively. No difference existed between the SUV(max) of the primary tumour and that from the related most intense lymph node metastasis. Moreover, the mean tumour to background ratio was 90% higher in the lymph nodes compared to the primary tumour (p = 0.006). Ninety-three per cent of the patients had sufficient uptake in the lymph nodes to qualify for subsequent response monitoring of the axilla. A considerable distinction in metabolic activity was observed between the different subtypes of breast cancer. The mean SUV(max) in lymph node metastases of oestrogen receptor (ER)-positive, triple-negative and human epidermal growth factor receptor 2 (HER2)-positive tumours was 6.6, 11.6 and 6.6, respectively. CONCLUSION: The high accuracy in visualizing lymph node metastases and the sufficiently high SUV(max) and tumour to background ratio at baseline suggest that it is feasible to monitor the axillary response with FDG PET/CT, especially in triple-negative tumours.

Utility of FDG PET/CT and brain MRI in melanoma patients with increased serum S-100B level during follow-up.

BACKGROUND: The serum level of the S-100B protein is increasingly used as a tumor marker in melanoma patients. The aims of this study were to assess the clinical relevance of increased S-100B during follow up of high-risk melanoma patients and to determine the value of subsequent whole-body PET/CT and brain MRI. MATERIALS AND METHODS: A retrospective analysis was performed of all 46 melanoma patients with a normal history and physical examination who were found to have an elevated serum S-100B level (> or =0.10 microg/L) during follow-up between August 2006 and March 2009. Suspicious lesions on FDG PET/CT were biopsied for histological or cytological confirmation or were imaged further and followed if no pathology confirmation could be obtained. RESULTS: The positive predictive value of an elevated serum S-100B was 50%. PET/CT revealed hypermetabolic lesions in 27 of the 46 patients (59%). PET/CT was never false negative as confirmed by median follow-up of 1 year but was false positive in 4 patients. MRI revealed brain metastases in 1 patient (2%). Of the 23 patients with a true positive PET/CT scan, 6 (26%) received surgical treatment with curative intent; the other 17 (74%) received palliative treatment or supportive care. The survival of patients with a normal PET/CT was longer than patients with a positive PET/CT (P = .002). CONCLUSIONS: An elevated serum S-100B during follow-up of high-risk melanoma patients has a modest 50% positive predictive value for recurrent disease. Subsequent PET/CT and MRI can identify patients with recurrent disease.

Feasibility of sentinel node detection in renal cell carcinoma: a pilot study.

PURPOSE: Lymphatic drainage from renal cell carcinoma is unpredictable and the therapeutic benefit and extent of lymph node dissection are controversial. We evaluated the feasibility of intratumoural injection of a radiolabelled tracer to image and sample draining lymph nodes in clinically non-metastatic renal cell carcinoma. METHODS: Eight patients with cT1-2 cN0 cM0 (<6 cm) renal cell carcinoma prospectively received percutaneous intratumoural injections of (99m)Tc-nanocolloid under ultrasound guidance (0.4 ml, 225 MBq at one to four intratumoural locations depending on tumour size). Lymphoscintigraphy was performed 20 min, 2 h and 4 h after injection. After the delayed images a hybrid SPECT/CT was performed. SPECT was fused with CT to determine the anatomical localization of the sentinel node. Surgery with sampling was performed the following day using a gamma probe and a portable mini gamma camera. RESULTS: Eight patients, seven with right-sided renal cell carcinoma, were included with a mean age of 55 years (range: 45-77). The mean tumour size was 4 cm (range: 3.5-6 cm). Six patients had sentinel nodes on scintigraphy (two retrocaval, four interaortocaval, including one hilar) with one extraretroperitoneal location along the internal mammary chain. All nodes could be mapped and sampled. In two patients no drainage was visualized. Renal cell carcinomas were of clear cell subtype with no lymph node metastases. CONCLUSION: Sentinel node identification using preoperative and intraoperative imaging to locate and sample the sentinel node at surgery in renal cell carcinoma is feasible. Sentinel node biopsy may clarify the pattern of lymphatic drainage and extent of lymphatic spread which may have diagnostic and therapeutic implications.

SPECT/CT for preoperative sentinel node localization.

The value of SPECT/CT for detection and localization of sentinel nodes is reviewed. SPECT/CT depicts extra sentinel nodes and identifies non-nodal tracer accumulation. SPECT/CT is indicated in patients with complex lymphatic drainage as often present in patients with head, neck and scapular melanoma, breast cancer patients with extra-axillary sentinel nodes and patients with tumors draining to pelvic nodes. SPECT/CT also clarifies the drainage pattern of inconclusive conventional images (non-visualization or unclear location of the nodes).

Repeat dynamic sentinel node biopsy in locally recurrent penile carcinoma.

OBJECTIVE: To explore the role of repeat dynamic sentinel-node biopsy (SNB) in clinically node-negative patients with locally recurrent penile carcinoma after previous penile surgery and SNB. PATIENTS AND METHODS: Between 1994 and 2008, 12 patients (4% of the 304 in our prospectively maintained dynamic sentinel node database) with clinically node-negative groins had a repeat SNB for locally recurrent penile carcinoma after previous penile surgery and SNB. Five of these patients had previously had a unilateral inguinal node dissection for groin metastases. The median disease-free interval was 18 months. The protocol and technique of primary dynamic SNB and the repeat procedure were similar, including preoperative lymphoscintigraphy and blue-dye injection. Completion inguinal node dissection was only done if there was an involved sentinel node. RESULTS: No sentinel nodes were seen on preoperative lymphoscintigraphy in the five groins that had previously been dissected. A sentinel node was visualized on lymphoscintigraphy in the remaining 19 undissected groins. In 15 of these groins (79%) the sentinel node was identified during surgery. Histopathological analysis showed involved sentinel nodes in four groins of three patients. Additional metastatic nodes were found in one completion inguinal lymph node dissection specimen. During a median follow-up of 32 months after the repeat SNB, one patient developed a groin recurrence 14 months after a tumour-negative sentinel node procedure. CONCLUSIONS: Repeat dynamic SNB is feasible in clinically node-negative patients with locally recurrent penile carcinoma despite previous SNB.

Lymphatic drainage patterns in breast cancer patients who previously underwent mantle field radiation.

BACKGROUND: Lymphatic drainage may change after radiation of a breast or its regional lymph node basins, and this may have implications for lymphatic mapping afterward. The aim of this study was to determine the lymphatic drainage patterns in breast cancer patients who had undergone mantle field radiation for Hodgkin's lymphoma in the past. METHODS: Between January 1999 and November 2008, 22 breast cancer patients underwent a sentinel node procedure after previous mantle field radiation. Lymphatic drainage patterns were analyzed based on lymphoscintigraphy and sentinel node biopsy. The results were compared with the drainage patterns in patients without previous treatment from an earlier study. RESULTS: Sentinel nodes were found in the axilla in 19 patients (86%) and 9 patients (41%) also had drainage toward extra-axillary regions. Sentinel nodes were more often found outside the axilla compared to the patients in our earlier study (33%, P = 0.04), and the nonidentification rate was also higher (14% vs. 3%, P = 0.01). Sentinel nodes were involved in 5 patients (23%). These were harvested from the internal mammary chain in two of them. No lymph node recurrences were observed during a median follow-up time of 49 months. CONCLUSION: Lymphatic mapping is feasible and yields a lymph node in 86% of the breast cancer patients after previous mantle field radiotherapy for Hodgkin's lymphoma. Nonvisualization and extra-axillary nodes are more frequently encountered than in patients without a history of mantle field radiation. The finding of involved nodes suggests that sentinel node biopsy improves staging. Long-term follow-up will determine the sensitivity of the procedure in this specific situation.

Two-center evaluation of dynamic sentinel node biopsy for squamous cell carcinoma of the penis.

PURPOSE: Sentinel node biopsy is used to evaluate the nodal status of patients with clinically node-negative penile carcinoma. Its use is not widespread, and the majority of patients with clinically node-negative disease undergo an elective inguinal lymph node dissection. Reservations about the use of sentinel node biopsy include the fact that most current results come from one institution and the supposedly long learning curve associated with the procedure. The purpose of this study was to address these issues by analyzing results from two centers and by evaluating the learning curve. PATIENTS AND METHODS: All patients undergoing sentinel node biopsy for penile carcinoma at two centers were included. The sentinel node identification rate, false-negative rate, and morbidity of the procedure were calculated. RESULTS: from the first 30 procedures were assessed for a potential learning curve. Results A total of 323 patients with penile squamous cell carcinoma, which included 611 clinically node-negative groins, were scheduled for sentinel node biopsy. A sentinel node was found in 572 of the 592 groins (97%) that proceeded to sentinel node biopsy. In 79 groins, a sentinel node was positive for tumor. Six inguinal node recurrences occurred after a negative sentinel node procedure, all within 15 months after sentinel node biopsy. The combined false-negative rate was 7%. Complications occurred in 4.7% of explored groins. None of the false-negative procedures occurred in the initial 30 procedures. CONCLUSION: Sentinel node biopsy is a suitable procedure to stage clinically node-negative penile cancer, and it has a low complication rate. No learning curve was demonstrated in this study.