De-escalation of axillary treatment in the event of a positive sentinel lymph node biopsy in cT1-2 N0 breast cancer treated with mastectomy: nationwide registry study (BOOG 2013-07).

BACKGROUND: Trials have demonstrated the safety of omitting completion axillary lymph node dissection in patients with cT1-2 N0 breast cancer operated with breast-conserving surgery who have limited metastatic burden in the sentinel lymph node. The aim of this registry study was to provide insight into the oncological safety of omitting completion axillary treatment in patients operated with mastectomy who have limited-volume sentinel lymph node metastasis. METHODS: Women diagnosed in 2013-2014 with unilateral cT1-2 N0 breast cancer treated with mastectomy, with one to three sentinel lymph node metastases (pN1mi-pN1a), were identified from the Netherlands Cancer Registry, and classified by axillary treatment: no completion axillary treatment, completion axillary lymph node dissection, regional radiotherapy, or completion axillary lymph node dissection followed by regional radiotherapy. The primary endpoint was 5-year regional recurrence rate. Secondary endpoints included recurrence-free interval and overall survival, among others. RESULTS: In total, 1090 patients were included (no completion axillary treatment, 219 (20.1%); completion axillary lymph node dissection, 437 (40.1%); regional radiotherapy, 327 (30.0%); completion axillary lymph node dissection and regional radiotherapy, 107 (9.8%)). Patients in the group without completion axillary treatment had more favourable tumour characteristics and were older. The overall 5-year regional recurrence rate was 1.3%, and did not differ significantly between the groups. The recurrence-free interval was also comparable among groups. The group of patients who did not undergo completion axillary treatment had statistically significantly worse 5-year overall survival, owing to a higher percentage of non-cancer deaths. CONCLUSION: In this registry study of patients with cT1-2 N0 breast cancer treated with mastectomy, with low-volume sentinel lymph node metastasis, the 5-year regional recurrence rate was low and comparable between patients with and without completion axillary treatment.

Omitting Axillary Dissection in Breast Cancer with Sentinel-Node Metastases.

BACKGROUND: Trials evaluating the omission of completion axillary-lymph-node dissection in patients with clinically node-negative breast cancer and sentinel-lymph-node metastases have been compromised by limited statistical power, uncertain nodal radiotherapy target volumes, and a scarcity of data on relevant clinical subgroups. METHODS: We conducted a noninferiority trial in which patients with clinically node-negative primary T1 to T3 breast cancer (tumor size, T1, ≤20 mm; T2, 21 to 50 mm; and T3, >50 mm in the largest dimension) with one or two sentinel-node macrometastases (metastasis size, >2 mm in the largest dimension) were randomly assigned in a 1:1 ratio to completion axillary-lymph-node dissection or its omission (sentinel-node biopsy only). Adjuvant treatment and radiation therapy were used in accordance with national guidelines. The primary end point was overall survival. We report here the per-protocol and modified intention-to-treat analyses of the prespecified secondary end point of recurrence-free survival. To show noninferiority of sentinel-node biopsy only, the upper boundary of the confidence interval for the hazard ratio for recurrence or death had to be below 1.44. RESULTS: Between January 2015 and December 2021, a total of 2766 patients were enrolled across five countries. The per-protocol population included 2540 patients, of whom 1335 were assigned to undergo sentinel-node biopsy only and 1205 to undergo completion axillary-lymph-node dissection (dissection group). Radiation therapy including nodal target volumes was administered to 1192 of 1326 patients (89.9%) in the sentinel-node biopsy-only group and to 1058 of 1197 (88.4%) in the dissection group. The median follow-up was 46.8 months (range, 1.5 to 94.5). Overall, 191 patients had recurrence or died. The estimated 5-year recurrence-free survival was 89.7% (95% confidence interval [CI], 87.5 to 91.9) in the sentinel-node biopsy-only group and 88.7% (95% CI, 86.3 to 91.1) in the dissection group, with a country-adjusted hazard ratio for recurrence or death of 0.89 (95% CI, 0.66 to 1.19), which was significantly (P<0.001) below the prespecified noninferiority margin. CONCLUSIONS: The omission of completion axillary-lymph-node dissection was noninferior to the more extensive surgery in patients with clinically node-negative breast cancer who had sentinel-node macrometastases, most of whom received nodal radiation therapy. (Funded by the Swedish Research Council and others; SENOMAC ClinicalTrials.gov number, NCT02240472.).

Sentinel node in breast cancer as an indicator of quality in medical care: Evaluation of statistics in Colombia.

BACKGROUND: Sentinel lymph node biopsy in breast cancer is considered the standard of staging in cases of clinically negative lymph nodes. Its omission in favor of axillary dissection generates significant morbidity. OBJECTIVE: To determine the total number of sentinel node biopsy procedures in breast cancer in Colombia from 2017 through 2020, model and analyze them as if they were performed only in stage I breast cancer patients, and integrate their results into the concepts of quality of medical care. METHODS: Search in a database of the Ministry of Health and Social Protection of Colombia with sentinel lymph node biopsy codes, and filters of breast cancer and year. Their results are contrasted with the number of cases in stage I of breast cancer. RESULTS: Breast cancer TNM staging was reported in 22154 cases, 3648 stage I. In the same time frame, the number of sentinel lymph node biopsies for breast cancer in Colombia was 1045, 28.64% of the total cases reported in stage I. CONCLUSIONS: Colombia is far from complying with the standard indicator of sentinel lymph node biopsy. It is recommended to concentrate breast cancer cases in hospitals that provide the conditions for its performance.

Survival associated with the use of one-step nucleic acid amplification (OSNA) to detect sentinel lymph node metastasis in cervical cancer.

INTRODUCTION: Sentinel lymph node (SLN) biopsy is part of surgical treatment of apparent early-stage cervical cancer. SLN is routinely analyzed by ultrastaging and immunohistochemistry. The aim of this study was to assess the survival of patients undergoing SLN analyzed by one-step nucleic acid amplification (OSNA) compared with ultrastaging. METHODS: Single-center, retrospective, cohort study. Patients undergoing primary surgery and SLN mapping ( ±pelvic lymphadenectomy) for apparent early-stage cervical cancer between May 2017 and January 2021 were included. SLN was analyzed exclusively with OSNA or with ultrastaging. Patients with bilateral SLN mapping failure, with SLN analyzed alternatively/serially with OSNA and ultrastaging, and undergoing neo-adjuvant therapy were excluded. Baseline clinic-pathological differences between the two groups were balanced with propensity-match analysis. RESULTS: One-hundred and fifty-seven patients were included, 50 (31.8%) in the OSNA group and 107 (68.2%) in the ultrastaging group. Median follow up time was 41 months (95%CI:37.9-42.2). 5-year DFS in patients undergoing OSNA versus ultrastaging was 87.0% versus 91.0% (p = 0.809) and 5-year overall survival was 97.9% versus 98.6% (p = 0.631), respectively. No difference in the incidence of lymph node recurrence between the two groups was noted (OSNA 20.0% versus ultrastaging 18.2%, p = 0.931). In the group of negative SLN, no 5-year DFS difference was noted between the two groups (p = 0.692). No 5-year DFS and OS difference was noted after propensity-match analysis (87.6% versus 87.0%, p = 0.726 and 97.4% versus 97.9%, p = 0.998, respectively). CONCLUSION: The use of OSNA as method to exclusively process SLN in cervical cancer was not associated with worse DFS compared to ultrastaging. Incidence of lymph node recurrence in the two groups was not different.

Development and validation of a novel model to predict recurrence-free survival and melanoma-specific survival after sentinel lymph node biopsy in patients with melanoma: an international, retrospective, multicentre analysis.

BACKGROUND: The introduction of adjuvant systemic treatment for patients with high-risk melanomas necessitates accurate staging of disease. However, inconsistencies in outcomes exist between disease stages as defined by the American Joint Committee on Cancer (8th edition). We aimed to develop a tool to predict patient-specific outcomes in people with melanoma rather than grouping patients according to disease stage. METHODS: Patients older than 13 years with confirmed primary melanoma who underwent sentinel lymph node biopsy (SLNB) between Oct 29, 1997, and Nov 11, 2013, at four European melanoma centres (based in Berlin, Germany; Amsterdam and Rotterdam, the Netherlands; and Warsaw, Poland) were included in the development cohort. Potential predictors of recurrence-free and melanoma-specific survival assessed were sex, age, presence of ulceration, primary tumour location, histological subtype, Breslow thickness, sentinel node status, number of sentinel nodes removed, maximum diameter of the largest sentinel node metastasis, and Dewar classification. A prognostic model and nomogram were developed to predict 5-year recurrence-free survival on a continuous scale in patients with stage pT1b or higher melanomas. This model was also calibrated to predict melanoma-specific survival. Model performance was assessed by discrimination (area under the time-dependent receiver operating characteristics curve [AUC]) and calibration. External validation was done in a cohort of patients with primary melanomas who underwent SLNB between Jan 30, 1997, and Dec 12, 2013, at the Melanoma Institute Australia (Sydney, NSW, Australia). FINDINGS: The development cohort consisted of 4071 patients, of whom 2075 (51%) were female and 1996 (49%) were male. 889 (22%) had sentinel node-positive disease and 3182 (78%) had sentinel node-negative disease. The validation cohort comprised 4822 patients, of whom 1965 (41%) were female and 2857 (59%) were male. 891 (18%) had sentinel node-positive disease and 3931 (82%) had sentinel node-negative disease. Median follow-up was 4·8 years (IQR 2·3-7·8) in the development cohort and 5·0 years (2·2-8·9) in the validation cohort. In the development cohort, 5-year recurrence-free survival was 73·5% (95% CI 72·0-75·1) and 5-year melanoma-specific survival was 86·5% (85·3-87·8). In the validation cohort, the corresponding estimates were 66·1% (64·6-67·7) and 83·3% (82·0-84·6), respectively. The final model contained six prognostic factors: sentinel node status, Breslow thickness, presence of ulceration, age at SLNB, primary tumour location, and maximum diameter of the largest sentinel node metastasis. In the development cohort, for the model's prediction of recurrence-free survival, the AUC was 0·80 (95% CI 0·78-0·81); for prediction of melanoma-specific survival, the AUC was 0·81 (0·79-0·84). External validation showed good calibration for both outcomes, with AUCs of 0·73 (0·71-0·75) and 0·76 (0·74-0·78), respectively. INTERPRETATION: Our prediction model and nomogram accurately predicted patient-specific risk probabilities for 5-year recurrence-free and melanoma-specific survival. These tools could have important implications for clinical decision making when considering adjuvant treatments in patients with high-risk melanomas. FUNDING: Erasmus Medical Centre Cancer Institute.

Sentinel node mapping in high-intermediate and high-risk endometrial cancer: Analysis of 5-year oncologic outcomes.

OBJECTIVE: To assess 5-year oncologic outcomes of apparent early-stage high-intermediate and high-risk endometrial cancer undergoing sentinel node mapping versus systematic lymphadenectomy. METHODS: This is a multi-institutional retrospective, propensity-matched study evaluating data of high-intermediate and high-risk endometrial cancer (according to ESGO/ESTRO/ESP guidelines) undergoing sentinel node mapping versus systematic pelvic lymphadenectomy (with and without para-aortic lymphadenectomy). Survival outcomes were assessed using Kaplan-Meier and Cox proportional hazard methods. RESULTS: Overall, the charts of 242 patients with high-intermediate and high-risk endometrial cancer were retrieved. Data on 73 (30.1%) patients undergoing hysterectomy plus sentinel node mapping were analyzed. Forty-two (57.5%) and 31 (42.5%) patients were classified in the high-intermediate and high-risk groups, respectively. Unilateral sentinel node mapping was achieved in all patients. Bilateral mapping was achieved in 67 (91.7%) patients. Three (4.1%) patients had site-specific lymphadenectomy (two pelvic areas only and one pelvic plus para-aortic area), while adjunctive nodal dissection was omitted in the hemipelvis of the other three (4.1%) patients. Sentinel nodes were detected in the para-aortic area in eight (10.9%) patients. Twenty-four (32.8%) patients were diagnosed with nodal disease. A propensity-score matching was used to compare the aforementioned group of patients undergoing sentinel node mapping with a group of patients undergoing lymphadenectomy. Seventy patient pairs were selected (70 having sentinel node mapping vs. 70 having lymphadenectomy). Patients undergoing sentinel node mapping experienced similar 5-year disease-free survival (HR: 1.233; 95%CI: 0.6217 to 2.444; p = 0.547, log-rank test) and 5-year overall survival (HR: 1.505; 95%CI: 0.6752 to 3.355; p = 0.256, log-rank test) than patients undergoing lymphadenectomy. CONCLUSIONS: Sentinel node mapping does not negatively impact 5-year outcomes of high-intermediate and high-risk endometrial cancer. Further prospective studies are warranted.

Risk factors and prognosis of sentinel lymph node metastasis in breast-conserving breast cancer: A retrospective study based on the SEER database.

At present, the risk factors and prognosis of sentinel lymph node metastasis (SLNM) are analyzed based on the study of axillary lymph node metastasis, but whether there is a difference between the two is unclear. Therefore, an accurate and appropriate predictive model needs to be proposed to evaluate patients undergoing sentinel lymph node biopsy (SLNB) for breast cancer. We selected 16983 women with breast cancer from the Surveillance Epidemiology and End Results (SEER) database. They were randomly assigned to two cohorts, one for development (n = 11891) and one for validation (n = 5092). multi-factor logistics regression was used to distinguish risk factors affecting SLNM. The potential prognostic factors were identified using the COX regression analysis. The hazard ratio (HR) and 95% confidence interval (95%CI) were calculated for all results. Multiple Cox models are included in the nomogram, with a critical P value of .05. In order to evaluate the model's performance, Concordance index and receiver operating characteristic curves were used. Six independent risk factors affecting SLNM were screened out from the Logistic regression, including tumor location, number of regional lymph nodes (2-5), ER positive, PR positive, tumor size (T2-3), and histological grade (Grade II-III) are independent risk factors for SLNM in patients (P < .05). Eight prognostic factors were screened out in the multivariate COX regression analysis (P < .05): Age: Age 60 to 79 years, Age ≥ 80 years; Race; Histological grading: Grade II, Grade III; No radiotherapy; Tumor size: T2, T3; ER positive:, sentinel lymph node positive, married. Histological grade, tumor location, T stage, ER status, PR status and the number of SLNB are significantly correlated with axillary SLNM. Age, ethnicity, histological grade, radiotherapy, tumor size, ER status, SLN status, and marital status were independent risk factors for Breast cancer specific survival (BCSS). Moreover, the survival rate of patients with 3 positive SLNs was not significantly different from that with one or two positive SLNs, We concluded that patients with stage N1 breast cancer were exempt from axillary lymph node dissection, which is worthy of further study.

Clinicopathological factors associated with sentinel lymph node detection in non-small-cell lung cancer.

BACKGROUND: Mapping of the pulmonary lymphatic system by near-infrared (NIR) fluorescence imaging might not always identify the first lymph node relay. The aim of this study was to determine the clinicopathologic factors allowing the identification of sentinel lymph nodes (SLNs) by NIR fluorescence imaging in thoracic surgery for non-small-cell lung cancer (NSCLC). METHODS: We conducted a retrospective review of 92 patients treated for suspected or confirmed cN0 lung cancer with curative intent who underwent an intraoperative injection of indocyanine green (ICG) either by direct peritumoral injection or by endobronchial injection using electromagnetic navigational bronchoscopy (ENB). After exclusion of patients for technical failure, benign disease and metastasis, we analyzed the clinicopathologic findings of 65 patients treated for localized-stage NSCLC, comparing the group with identification of SLNs (SLN-positive group) with the group without identification of SLNs (SLN-negative group). RESULTS: Forty-eight patients (73.8%) were SLN-positive. Patients with SLN positivity were more frequently female (50%) than the SLN-negative patients were (11.8%) (p = 0.006). The mean value of diffusing capacity for carbon monoxide (DLCO) was lower among the patients in the SLN-negative group (64.7% ± 16.7%) than the SLN-positive group (77.6% ± 17.2%, p < 0.01). The ratio of forced expiratory volume in one second to forced vital capacity (FEV1/FCV) was higher in the SLN-positive group (69.0% vs. 60.8%, p = 0.02). Patients who were SLN-negative were characterized by a severe degree of emphysema (p = 0.003). There was no significant difference in pathologic characteristics. On univariate analyses, age, female sex, DLCO, FEV1/FVC, degree of emphysema, and tumor size were significantly associated with SLN detection. On multivariate analysis, DLCO > 75% (HR = 4.92, 95% CI: 1.27-24.7; p = 0.03) and female sex (HR = 5.55, 95% CI: 1.25-39.33; p = 0.04) were independently associated with SLN detection. CONCLUSIONS: At a time of resurgence in the use of the sentinel lymph node mapping technique in the field of thoracic surgery, this study enabled us to identify, using multivariate analysis, two predictive factors for success: DLCO > 75% and female sex. Larger datasets are needed to confirm our results.

Clipping a Positive Lymph Node Improves Accuracy of Nodal Staging After Neoadjuvant Chemotherapy for Breast Cancer Patients, but Does It Drive Management Changes?

BACKGROUND: Sentinel lymph node (SLN) biopsy for cN+ breast cancer patients after neoadjuvant chemotherapy (NAC) is controversial because the false-negative rate (FNR) is high. Identification of three or more SLNs with a dual tracer improves these results, and inclusion of a clipped lymph node (CLN) (targeted axillary dissection [TAD]) may be even more effective. METHODS: A retrospective, single-institution analysis of consecutive cN+ patients undergoing NAC from 2019 to 2021 was performed. Patients routinely underwent placement of a clip in the positive lymph node before NAC, and TAD was performed after completion of therapy. RESULTS: The study analyzed 73 patients, and the identification rate for CLN was 98.6% (72/73). A complete response in the lymph nodes was achieved for 43 (59%) of the 73 patients. Overall, the CLN was not a SLN in 18 (25%) of 73 cases, and for women who had one or two and those who had three or more SLNs identified, this occurred in 11 (32%) and 7 (21%) of 34 cases, respectively. Failure of SLN or TAD to identify a positive residual lymph node status after NAC occurred in 10 (15%) of 69 and 2 (3%) of 73 cases, respectively (p = 0.01). In four cases, a SLN was not retrieved (5.5%), and two of these cases had a positive CLN. In three cases, the CLN was the only positive node and did not match with a SLN, directing lymphadenectomy and oncologic management change in two cases. Therefore, 7 (10%) of 73 cases had a change in surgical or oncologic management with TAD. CONCLUSIONS: For a conservative axillary treatment in this setting, TAD is an effective method. It is more accurate than SLN alone and allows management changes. Further studies are warranted.

Germinal centres within tumour positive sentinel lymph nodes are positively associated with tumour infiltrating lymphocytes and tertiary lymphoid structures in breast cancer.

BACKGROUND: Stromal tumour infiltrating lymphocytes (sTILs) and presence of tertiary lymphoid structures have been proposed as indicators of tumour-related immune response in breast cancer. An increased number of germinal centres (GCs) in lymph nodes is considered a sign of humoral immune reactivity. AIMS: It is unclear whether a relationship exists between number and size of GCs within tumour positive sentinel lymph nodes (SLNpos), sTILs and tertiary lymphoid structures within matched primary breast cancer and breast cancer subtype. METHODS: Axillary SLNpos from 175 patients with breast cancer were manually contoured in digitized haematoxylin and eosin stained sections. Total SLN area, GC number and GC area were measured in SLNpos with the largest metastatic area. To correct for SLN size, GC number and GC area were divided by SLN area. sTILs and presence of tertiary lymphoid structures were assessed in the primary breast cancer. RESULTS: A higher GC number and larger GC area were found in patients with high sTILs (≥2%) (both P < 0.001) and in patients with presence of tertiary lymphoid structures (PGC number = 0.034 and PGC area = 0.016). Triple negative and HER2-positive (N = 45) breast cancer subtypes had a higher GC number and higher sTILs compared to hormone receptor positive, HER2-negative breast cancer (N = 130) (PGC number < 0.001 and PsTILs= 0.001). CONCLUSION: This study suggests GCs measured within SLNpos might be useful indicators of the humoral anti-tumour immune response in breast cancer. Future studies are needed investigating underlying biological mechanisms and prognostic value of GCs in SLNs.

Identifying safe diagnostic algorithms for sentinel lymph node mapping in high-risk endometrial cancer: The SENTIREC-endo study.

INTRODUCTION: It is unclear if sentinel node (SLN) mapping can replace pelvic- (PLD) and paraaortic lymphadenectomy (PALD) for high-risk endometrial cancer (EC). A diagnostically safe surgical algorithm, taking failed mapping cases into account, is not defined. We aimed to investigate the diagnostic accuracy of SLN mapping algorithms in women with exclusively high-risk EC. METHODS: We undertook a prospective national diagnostic cohort study of SLN mapping in women with high-risk EC from March 2017 to January 2023. The power calculation was based on the negative predictive value (NPV). Women underwent SLN mapping, PLD and PALD besides removal of suspicious and any FDG/PET-positive lymph nodes. Accuracy analyses were performed for five algorithms. RESULTS: 170/216 included women underwent SLN mapping, PLD and PALD and were included in accuracy analyses. 42/170 (24.7%) had nodal metastasis. The algorithm SLN and PLD in case of failed mapping, demonstrated a sensitivity of 86% (95% CI 74-100) and an NPV of 96% (95% CI 91-100). The sensitivity increased to 93% (95% CI 83-100) and the NPV to 98% (95% CI 94-100) if PLD was combined with removal of any PET-positive lymph nodes. Equivalent results were obtained if PLD and PALD were performed in non-mapping cases; sensitivity 93% (95% CI 83-100) and NPV 98% (95% CI 95-100). CONCLUSION: SLN-mapping is a safe staging procedure in women with high-risk EC if strictly adhering to a surgical algorithm including removal of any PET-positive lymph nodes independent of location and PLD or PLD and PALD in case of failed mapping.

NIR-II Ratiometric Fluorescence Probes Enable Precise Determination of the Metastatic Status of Sentinel Lymph Nodes.

Accurately determining the metastatic status of sentinel lymph nodes (SLNs) through noninvasive imaging with high imaging resolution and sensitivity is crucial for cancer therapy. Herein, we report a dual-tracer-based NIR-II ratiometric fluorescence nanoplatform combining targeted and nontargeted moieties to determine the metastatic status of SLNs through the recording of ratio signals. Ratiometric fluorescence imaging revealed approximately 2-fold increases in signals in tumor-draining SLNs compared to inflamed and normal SLNs. Additionally, inflamed SLNs were diagnosed by combining the ratio value with the enlarged size outputted by NIR-II fluorescence imaging. The metastatic status diagnostic results obtained through NIR-II ratiometric fluorescence signals were further confirmed by standard H&E staining, indicating that the ratiometric fluorescence strategy could achieve distant metastases detection. Furthermore, the superior imaging quality of ratiometric probes enables visualization of the detailed change in the lymphatic network accompanying tumor growth. Compared to clinically available and state-of-the-art NIR contrast agents, our dual-tracer-based NIR-II ratiometric fluorescence probes provide significantly improved performance, allowing for the quick assessment of lymphatic function and guiding the removal of tumor-infiltrating SLNs during cancer surgery.

Multidisciplinary radio-guided surgery team: Alternative to change the current paradigm.

INTRODUCTION: Given the constant increase in the healthcare demand for examinations related to radio-guided surgery (RGS), our hospital adopted new professional profiles in the RGS team, in order to partially reduce the time spent by nuclear medicine physicians on this task. AIM: To analyze the process of incorporating the profiles of Diagnostic Imaging Technician (DIT) and Sentinel Node Referent Nurse (SNRN), evaluating their deployment in the procedures linked to the technique. MATERIAL AND METHODS: Analysis of RGS activity during the period 2018-2022, focusing on pre-surgical and surgical procedures related to breast cancer (BC) and malignant melanoma (MM), as they are those pathologies on which the transfer of care competencies was concentrated. Chronological evolution of the competencies assumed by the different profiles during their integration into the RGS team. RESULTS: RGS's healthcare activity during the analyzed period experienced an increase of 109%. BC and MM were the pathologies that accounted for by far the greatest demand for care. The transfer of competencies in these two pathologies occurred in a progressive and staggered manner, with 74% (460/622) of the administration phase being carried out by the SNRN and 64% (333/519) of the surgeries by the DIT in 2022. CONCLUSIONS: The creation of a multidisciplinary RGS team that includes different professional profiles (nuclear medicine physician [MN], ERGC and TSID) is an effective strategy to respond to the increase in the complexity and number of all procedures related to RGS.

Concordance between freehand SPECT and conventional scintigraphy for sentinel lymph node detection in breast cancer.

INTRODUCTION: Freehand SPECT can be a useful imaging technique for preoperative planning of sentinel lymph node biopsy (SLNB) as it allows localization of the sentinel node by 3D and real-time tomographic imaging and determines its depth after a few minutes of scanning. The aim of the study was to evaluate the correlation between the number of detected SNs between freehand SPECT images and lymphoscintigraphy (LS). MATERIALS AND METHODS: 100 patients with a diagnosis of invasive breast cancer and no clinical evidence of lymph node involvement prospectively underwent SLNB. The preoperative study included freehand SPECT imaging at 15min after injection and LS imaging at 25 and 60-90min after injection (early and late). The observed agreement was analyzed and a concordance study was performed between the number of SNs detected with freehand SPECT and LS. RESULTS: The observed agreement in the detection of SNs between freehand SPECT and early LS was 72%; between freehand SPECT and late LS was 85%; and between early and late LS was 87%. In the concordance study, there was moderate concordance between freehand SPECT and early LS (kappa coefficient: 0.42); moderate-high concordance between freehand SPECT and late LS (kappa coefficient: 0.60); and moderate-high concordance between early and late LS (kappa coefficient: 0.70), with no significant differences between them (p-value=0.16). CONCLUSION: Freehand SPECT showed a moderate-high concordance with conventional imaging studies and could be a valid alternative for the presurgical study of SLNB in breast cancer.

CT features of cutaneous and subcutaneous canine mast cell tumors and utility of conventional and indirect lymphography to detect clinically unknown mast cell tumors and to map the sentinel lymph nodes.

Computed tomography is frequently used to stage canine mast cell tumors (MCTs). The aims of this prospective, observational study were to describe the CT features of MCTs, to evaluate the performance of CT in detecting additional or incidental MCTs, to distinguish between cutaneous (cMCT) or subcutaneous (scMCT) MCTs, and to identify one or multiple sentinel lymph nodes (SLNs) by indirect CT lymphography (ICTL). Seventy-two dogs affected by 111 MCTs were included. The recorded parameters were: shape, size, attenuation (Hounsfield units [HU]), location (cutaneous or subcutaneous), and presence of fat stranding. The SLNs were compared with the regional lymph nodes and supplementary MCTs were registered. Mast cell tumors mostly appeared with well-defined margins (89%), round/oval shape (71%), homogeneous enhancement (90%) with a mean postcontrast density of 62.0 ± 23.4 HU and associated with fat stranding (43%). Cutaneous mast cell tumors were more frequently round (P = .003), whereas scMCTs were oval (P = .011) with a larger mean maximal diameter (2.91 ± 1.57 cm vs 1.46 ± 1.28 cm, P = .002) and more feeding vessels (77% vs 39% P = .044). Compared with histopathology, CT accuracy in differentiating cMCTs and sMCTs was 57%, with an interobserver agreement of 88% (three reviewers). Indirect CT lymphography showed the SLN in 82 of 85 (97%) cases, 32% of them not corresponding to the regional node. CT showed additional or incidental MCTs in 23 of 72 (32%) dogs. In conclusion, the common CT appearance of canine cMCTs and scMCTs is reported with some statistical differences between the two categories. CT is useful in identifying clinically undetected MCTs and SLNs, although it shows low accuracy in distinguishing between cMCT and scMCT.