Hybrid imaging by SPECT/CT for sentinel lymph node detection in patients with cancer of the uterine cervix

Molecular image-guided surgery in gynaecological cancer: where do we stand?

PURPOSE

The aim of this review is to give an overview of the current status of molecular image-guided surgery in gynaecological malignancies, from both clinical and technological points of view.

METHODS

A narrative approach was taken to describe the relevant literature, focusing on clinical applications of molecular image-guided surgery in gynaecology, preoperative imaging as surgical roadmap, and intraoperative devices.

RESULTS

The most common clinical application in gynaecology is sentinel node biopsy (SNB). Other promising approaches are receptor-target modalities and occult lesion localisation. Preoperative SPECT/CT and PET/CT permit a roadmap for adequate surgical planning. Intraoperative detection modalities span from 1D probes to 2D portable cameras and 3D freehand imaging.

CONCLUSION

After successful application of radio-guided SNB and SPECT, innovation is leaning towards hybrid modalities, such as hybrid tracer and fusion of imaging approaches including SPECT/CT and PET/CT. Robotic surgery, as well as augmented reality and virtual reality techniques, is leading to application of these innovative technologies to the clinical setting, guiding surgeons towards a precise, personalised, and minimally invasive approach.

Validation of single-photon emission computed tomography with computed tomography and lymphoscintigraphy for sentinel lymph node identification in cervical cancer

OBJECTIVE

To compare single-photon emission computed tomography with computed tomography (SPECT/CT) and lymphoscintigraphy (LSG) for the detection of sentinel lymph nodes (SLNs) in patients with early-stage cervical cancer.

METHODS

This hospital-based, single-center, retrospective study included 128 patients with cervical cancer (aged >18 years) treated between 2014 and 2022. Injection of 99 m Technetium-labeled phytate into the uterine cervix was used to detect pelvic SLNs. SNL identification rates and locations were analyzed for preoperative LSG and SPECT/CT.

RESULTS

Median age and body mass index of patients were 40 years (range, 20-78 years) and 21.7 kg/m2 (range, 16-40 kg/m2 ), respectively. There was no significant difference in overall identification rates (identification of at least one SLN) of SLNs between SPECT/CT (91%) and LSG (88%). There was no significant difference in bilateral SLN identification rates between SPECT/CT (66%) and LSG (65%). A total of 219 pelvic SLNs (110 right and 109 left hemipelvis) were identified by SPECT/CT; the most frequent locations were the obturator (122 SLNs, 56%) and external iliac (67 SLNs, 30%).

CONCLUSION

SPECT/CT and LSG showed high SLN identification rates in patients with cervical cancer, and there was no significant difference in overall or bilateral SLN identification rates between the two techniques.

Comparison of SPECT-CT with intraoperative mapping in cervical and uterine malignancies

INTRODUCTION

The objective was to evaluate whether hybrid imaging combining single photon emission tomography with computed tomography (SPECT/CT) provides additional clinical value for dectection of sentinel lymph nodes (SLNs) compared with intraoperative combined mapping in uterine and cervical malignancies.

METHODS

This was a retrospective study of prospectively collected data from patients with stages IA-IB2 cervical cancer (International Federation of Gynecology and Obstetrics (FIGO) 2018) or stage I endometrial cancer, who underwent preoperative SPECT/CT for SLN detection. All included patients had dual injection of technetium-99m (99mTc) with patent blue or indocyanine green.

RESULTS

A total of 171 patients were included with 468 SLNs detected during surgery: 146/171 patients (85.4%) had both radiotracer and blue injection whereas 25/171 patients (14.6%) had radiotracer and indocyanine green injected. The overall detection rate was 95.3%. The detection rate of SLN mapping was 74.9% for SPECT/CT, 90.6% for 99mTc, 91.8% for blue dye, and 100% for indocyanine green. Bilateral drainage was found in 140 patients (81.9%), detected by 99mTc in 105 patients (61.4%), by blue in 99 patients (67.3%), by indocyanine green in 23 patients (92%), and by SPECT/CT in 62 patients (36.4%). Atypical SLN locations were identified by SPECT/CT in 64 patients (37.4%), by 99mTc in 28 patients (16.4%), by blue in 17 patients (9.9%), and by indocyanine green in 8 patients (4.7%). Sensitivity and negative predictive value of SLN biopsy to detect lymph node metastasis using dual injection of different intraoperative combined techniques were 88.9% and 97.5%, respectively.

CONCLUSION

SPECT/CT enhanced topographic delineation of SLN and more accurately identified drainage to atypical locations. Fluorescent SLN mapping using indocyanine green offered the highest SLN detection rate. When indocyanine green was used, SPECT/CT did not increase SLN detection, and did not add further information to improve lymph node localization and removal.

Pathologic Protocols for Sentinel Lymph Nodes Ultrastaging in Cervical Cancer

CONTEXT.—

Ultrastaging of sentinel lymph nodes (SLNs) is a crucial aspect in the approach to SLN processing. No consensual protocol for pathologic ultrastaging has been approved by international societies to date.

OBJECTIVE.—

To provide a review of the ultrastaging protocol and all its aspects related to the processing of SLNs in patients with cervical cancer.

DATA SOURCES.—

In total, 127 publications reporting data from 9085 cases were identified in the literature. In 24% of studies, the information about SLN processing is entirely missing. No ultrastaging protocol was used in 7% of publications. When described, the differences in all aspects of SLN processing among the studies and institutions are substantial. This includes grossing of the SLN, which is not completely sliced and processed in almost 20% of studies. The reported protocols varied in all aspects of SLN processing, including the thickness of slices (range, 1-5 mm), the number of levels (range, 0-cut out until no tissue left), distance between the levels (range, 40-1000 μm), and number of sections per level (range, 1-5).

CONCLUSIONS.—

We found substantial differences in protocols used for SLN pathologic ultrastaging, which can impact sensitivity for detection of micrometastases and even small macrometastases. Since the involvement of pelvic lymph nodes is the most important negative prognostic factor, such profound discrepancies influence the referral of patients to adjuvant radiotherapy and could potentially cause treatment failure. It is urgent that international societies agree on a consensual protocol before SLN biopsy without pelvic lymphadenectomy is introduced into routine clinical practice.

[Sentinel lymph node biopsy in early-stage cervical cancer: current state of art]

Lymph node status is the most important prognostic factor of survival in women with early stage cervical cancer. Sentinel lymph node (SLN) biopsy is an accurate method for the assessment of lymph nodal involvement in early-stages cervical cancer and has been increasingly used instead of systematic pelvic lymph node dissection (PLND). Less-radical lymph node dissection decreases the associated morbidity of PLND, especially the risk of lower-leg lymphoedema, which affects severely patient quality of life. SLN biopsy allows nodes ultrastaging and provides supplementary histological information by increasing the detection of tumor low-volume (isolated tumors cells and micrometastases). Moreover, SLN biopsy provides accurate anatomical information on pelvic lymphatic drainage pathway by identifying nodes outside of routine lymphadenectomy areas. Selection of a population at low-risk of nodal metastasis, a minimal training, and simple rules may ensure a low false negative rate. Several studies have shown that SLN mapping in these patients is feasible, with excellent detection rates and sensitivity. Combined detection with technetium-99 and blue dye has been widely used but recently, there has been increasing interest in the use of fluorescent dies such as indocyanine green (ICG) which would improve SLN detection. Although recent international guidelines recommend performing SLN biopsy in addition to PLND, SLN biopsy alone is not the gold-standard yet due to lack of prospective evidence, especially on long-term oncological safety. Some points remain controversial such as the low accuracy of intraoperative SLN status assessment by frozen section and the impact of micrometastasis on prognostic. The prospective randomized clinical trial SENTICOL III will answer to these problematics.

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.

Investigating the role of SPECT/CT in dynamic sentinel lymph node biopsy for penile cancers

Purpose

Currently, most centres use 2-D planar lymphoscintigraphy when performing dynamic sentinel lymph node biopsy in penile cancer patients with clinically impalpable inguinal nodes. This study aimed to investigate the role of SPECT/CT following 2-D planar lymphoscintigraphy (dynamic and static) in the detection and localization of sentinel lymph nodes in the groin.

Methods

A qualitative (visual) review was performed on planar followed by SPECT/CT lymphoscintigraphy in 115 consecutive patients (age 28–86 years) who underwent injection of ^99mTc-nanocolloid followed by immediate acquisition of dynamic (20 min) and early static scans (5 min) initially and further delayed static (5 min) images at 120 min followed by SPECT/CT imaging. The lymph nodes detected in each groin on planar lymphoscintigraphy and SPECT/CT were compared.

Results

A total of 440 and 467 nodes were identified on planar scintigraphy and SPECT/CT, respectively. Overall, SPECT/CT confirmed the findings of planar imaging in 28/115 cases (24%). In the remaining 87 cases (76%), gross discrepancies were observed between planar and SPECT/CT images. SPECT/CT identified 17 instances of skin contamination (16 patients, 13%) and 36 instances of in-transit lymphatic tract activity (24 patients, 20%) that had been interpreted as tracer-avid lymph nodes on planar imaging. In addition, SPECT/CT identified 53 tracer-avid nodes in 48 patients (42%) that were not visualized on planar imaging and led to reclassification of the drainage basins (pelvic/inguinal) of 27 tracer-avid nodes.

Conclusions

The addition of SPECT/CT improved the rate of detection of true tracer-avid lymph nodes and delineated their precise (3-D) anatomic localization in drainage basins.

Pericervical Injection of 99mTc-Nanocolloid Is Superior to Peritumoral Injection for Sentinel Lymph Node Detection of Endometrial Cancer in SPECT/CT

PURPOSE

Scintigraphic mapping of sentinel lymph node (SLN) is increasingly performed in patients with endometrial carcinoma although its routine clinical use is still under investigation. The purpose of this study was to compare preoperative SLN detection by means of SPECT/CT using pericervical (PC) versus hysteroscopic peritumoral (PT) injection.

PATIENTS AND METHODS

One hundred forty consecutive patients with endometrial carcinoma who underwent surgery and preoperative SLN SPECT/CT with Tc-nanocolloid were included. Seventy women received hysteroscopic injection at 3 PT sites, and 70 women received PC injection at 3-, 6-, 9-, and 12-o'clock positions. Each patient underwent SPECT/CT followed by modified radical hysterectomy with lymphadenectomy on the day after. Histopathological results were collected for validation.

RESULTS

Three hundred thirty-four SLNs were detected by SPECT/CT in 106 patients (mean, 3.15; range, 1-9). The detection rate after PC nanocolloid injection was 83% versus 69% after PT injection (Pearson χ test, P = 0.049). However, PT application resulted in a higher rate of para-aortic SLNs (PC: 60% vs PT: 38% of positive scans, P = 0.02). SPECT/CT yielded an overall sensitivity of 70% for the SLN detection in women with lymph node metastases with 3 false-negative cases. Failure to detect SLN was mostly associated with uptake in the reticuloendothelial system (liver, spleen, and bone marrow) or peritoneal diffusion in both cohorts. Negative scans after PT application often showed a minor to even failing injection depot.

CONCLUSIONS

Pericervical injection leads to a significantly better detection rate of SLN on SPECT/CT while reducing invasiveness of the injection procedure. Failure to detect SLN seems to be associated with major venous drainage.

The sentinel node approach in gynaecological malignancies

This review discusses the state-of-the-art of sentinel lymph node mapping in gynaecological malignancies, including cervical cancer, endometrial cancer, and vulvar cancer, with an emphasis on new technological advances. For this objective, PubMed/MEDLINE was searched for relevant studies about the sentinel lymph node procedure in gynaecology. In particular, the use of preoperative lymphatic mapping with lymphoscintigraphy and single photon emission tomography/computed tomography (SPECT/CT) was identified in 18 studies. Other recent advances as hybrid tracers (e.g. ICG-^99mTc-nanocolloid) and intraoperative tools (portable γ-camera and 3D navigation devices) appear to also represent a useful guide for the surgeon during the operation. Concerning vulvar and cervical cancers, the sentinel lymph node procedure has been incorporated to the current guidelines in Europe and North America, whereas for endometrial cancer it is considered investigative.

Location of Sentinel Lymph Node in Cervical Carcinoma and Factors Associated With Unilateral Detection

OBJECTIVE

The aims of this study were to assess locality of the sentinel lymph node (SLN) in cervical carcinoma and examine factors affecting bilateral SLN detection.

METHODS

This was a retrospective review of SLN data (anatomical location, count and laterality) in patients with early-stage cervical cancer (International Federation of Gynecology and Obstetrics stage IA1 with lymphovascular space invasion to stage IIA) using intraoperative gamma probe and blue dye. The preoperative single-photon emission computed tomography with computed tomography was used to detect laterality, number of the SLNs, and rare locations. Patients were treated between January 2005 to January 2015 at the West Kent Gynaecological Oncology Centre, Maidstone Hospital, Maidstone, United Kingdom.

RESULTS

A total of 132 women were investigated. The most common SLN location was the external iliac (38.6%) followed by obturator (25.3%) and internal iliac (23.6%) regions. A small percentage was identified in presacral (1.4%) and para-aortic regions (0.7%). Older age (P = 0.01) and an elevated body mass index (P = 0.03) were associated with decreased SLN count by preoperative single-photon emission computed tomography with computed tomography, and only age affected SLN count by gamma probe (P = 0.01). Initial surgery, large loop excision of the transformation zone, or cone biopsy of the cervix had no effect on SLN count. There was no difference observed in bilateral detection with respect to surgical approach (open: n = 48/laparoscopic: n = 84). However, older age was independently associated with a decrease in bilateral SLN detection (P = 0.003). In these patients who underwent unilateral full pelvic lymphadenectomy, all the nonsentinel nodes were negative.

CONCLUSIONS

The majority of SLNs were located in the external iliac, obturator, and internal iliac regions. Both older age and an elevated body mass index were associated with a reduced SLN count. Unilateral detection of SLN was independently associated with older age, which may be due to sclerosis in the lymphatic vessels or reduced perfusion in the pelvis in these women. If no SLN is detected on one side, the consensus is to perform a full pelvic lymphadenectomy on that side of the pelvis.

SPECT/CT for SLN dissection in vulvar cancer: Improved SLN detection and dissection by preoperative three-dimensional anatomical localisation

OBJECTIVE

In this study, we assessed the feasibility and clinical advantages of single photon emission computed tomography with CT (SPECT/CT) for sentinel lymph node (SLN) detection in vulvar cancer.

METHODS

This is a unicentric prospective trial. Vulvar cancer patients underwent preoperative SLN marking (10MBq Technetium (TC)-99m-nanocolloid) and subsequent planar lymphoscintigraphy (LSG) and SPECT/CT for SLN visualization. Directly before surgery, a patent blue dye was injected. We assessed detection rates of SPECT/CT and those of planar LSG and intraoperative detection. We analyzed the sensitivity, negative predictive value and false negative rate.

RESULTS

At Hannover Medical School, 40 vulvar cancer patients underwent SLN dissection after preoperative LSG and SPECT/CT. The mean diameter of all tumors in final histology was 2.23 (0.1-10.5) cm with a mean tissue infiltration of 3.93 (0.25-11) mm. In preoperative imaging, SPECT/CT identified significantly more SLNs (mean 8.7 (1-35) LNs per patient) compared to LSG (mean 5.9 (0-22) LNs, p<0.01). In addition, SPECT/CT led to a high spatial resolution and anatomical localization of SLNs. Thus, SPECT/CT identified aberrant lymphatic drainage in 7/40 (17.5%) patients. There were no significant differences, but significant correlation was found between SPECT/CT and intraoperative SLN identification. Regarding inguino-femoral LNs, for all patients who underwent complete groin dissection, sensitivity was 100%, NPV was 100% and false negative rate was 0%.

CONCLUSION

SPECT/CT leads to higher SLN identification compared to LSG in vulvar cancer. Due to its higher spatial resolution and three-dimensional anatomical localisation of SLNs, SPECT/CT provides the surgeon with important additional information, facilitates intraoperative SLN detection and predicts aberrant lymphatic drainage.

99mTc SPECT/CT Versus Planar Lymphoscintigraphy for Preoperative Sentinel Lymph Node Detection in Cervical Cancer: A Systematic Review and Metaanalysis

We aimed to compare SPECT/CT and lymphoscintigraphy on overall and bilateral sentinel lymph node (SLN) detection in cervical cancer patients.

METHODS

A systematic search was performed on August 1, 2014, in PubMed, Embase, Scopus, and the Cochrane library. The syntax was based on synonyms of the terms cervical cancer, SPECT/CT, and lymphoscintigraphy. Retrieved articles were screened on their title/abstract and considered eligible when an SLN procedure was performed using both imaging modalities and if detection results were reported. Two independent reviewers assessed all included studies on methodologic quality using QUADAS-2. Studies were pooled on their odds ratios (ORs) with a random-effects model.

RESULTS

The search yielded 962 unique articles, of which 8 were ultimately included. The studies were recent retrospective or prospective cohort studies of limited size (n = 7-51) but sufficient methodologic quality. The median overall detection (≥1 SLN in a patient) was 98.6% for SPECT/CT (range, 92.2%-100.0%) and 85.3% for lymphoscintigraphy (range, 70.0%-100.0%). This corresponded to a pooled overall SLN detection OR of 2.5 (95% CI, 1.2-5.3) in favor of SPECT/CT. The reported median bilateral detection (≥1 SLN in each hemipelvis) was 69.0% for SPECT/CT (range, 62.7%-79.3%) and 66.7% for lymphoscintigraphy (range, 56.9%-75.8%), yielding a pooled OR of 1.2 (95% CI, 0.7-2.1). No significant difference in the number of visualized SLNs was observed at a pooled ratio of 1.2 (95% CI, 0.9-1.6).

CONCLUSION

In cervical cancer patients, preoperative SLN imaging with SPECT/CT results in superior overall SLN detection in comparison with planar lymphoscintigraphy.

Sentinel-lymph-node procedures in early stage cervical cancer: a systematic review and meta-analysis

We performed a meta-analysis to assess the accuracy of sentinel-lymph-node (SLN) procedures for the assessment of nodal metastases in patients with early stage cervical cancer. Studies of SLN procedures for detecting nodal metastases in patients with early stage cervical cancer were systematically searched in MEDLINE and EMBASE between January 1, 2000 and August 30, 2013. We identified 49 eligible studies, which included 2,476 SLN procedures. The mean overall weighted-detection rate was 0.93 (95 % CI 0.92–0.94), at a pooled sensitivity of 0.88 (95 % CI 0.84–0.90) with limited heterogeneity (χ² = 80.57, degrees of freedom = 47, p = 0.002). Subgroup analysis of sensitivity and the rate of detection of different tracer techniques and surgery methods used in conjunction with an SLN procedures were as follows: studies using combined techniques, 0.88 (95 % CI 0.84–0.91) and 0.97 (95 % CI 0.96–0.98); studies using metastable technetium-99, 0.87 (95 % CI 0.78–0.93) and 0.90 (95 % CI 0.87–0.93); studies using blue dye, 0.87 (95 % CI 0.79–0.93) and 0.87 (95 % CI 0.84–0.90); studies using laparotomy, 0.86 (95 % CI 0.80–0.90) and 0.87 (95 % CI 0.83–0.91); studies using laparoscopy, 0.90 (95 % CI 0.86–0.94) and 0.93 (95 % CI 0.90–0.96); and studies using robot-assisted surgery, 0.84 (95 % CI 0.72–0.92) and 0.92 (95 % CI 0.88–0.95). We concluded that the SLN procedure performs well diagnostically for the assessment of nodal metastases in patients with early stage cervical cancer.

Feasibility and performance of lymphoscintigraphy in sentinel lymph node biopsy for early cervical cancer: results of the prospective multicenter SENTICOL study

Objective

To evaluate feasibility, SLN detection rate, and SLN location of lymphoscintigraphy in sentinel lymph node (SLN) biopsy for early cervical cancer.

Methods

Ancillary analysis of data from the multicenter prospective SENTICOL study (January 2005–June 2007) of patients with early cervical cancer (FIGO stage IA with emboli to IB1) was conducted. Preoperative lymphoscintigraphy was performed after intracervical administration of 60 or 120 MBq of ^99mTc-labeled radiocolloid on the day before (long protocol) or morning of (short protocol) surgery. SLNs were identified intraoperatively using combined radioactivity/patent blue detection. SLNs were sampled electively and routine bilateral pelvic lymphadenectomy was performed by laparoscopy. A centralized review of lymphoscintigraphies was performed to assess feasibility, detection rates, and anatomic SLN location.

Results

Of 139 patients included in the SENTICOL study, 133 received radiocolloid injection, and 131 (98.5 %) underwent preoperative lymphoscintigraphy, with the long protocol in three-fourths of cases. The lymphoscintigraphic detection rate was 87.8 %, with a median of 2 (1–4) SLNs per patient. By multivariate analysis, factors independently associated with lymphoscintigraphic SLN detection were age [odds ratio (OR) 0.91, 95 % confidence interval (95 % CI) 0.87–0.96; P < 0.001], and protocol (long vs. short; OR 8.23, 95 % CI 1.87–36.25; P = 0.005). Bilateral SLN identification by lymphoscintigraphy occurred in 67 % of cases and was independently influenced by age (OR 0.95, 95 % CI 0.92–0.98, P < 0.001) and protocol (OR 5.42, 95 % CI 2.21–13.27; P < 0.001). Although 60.5 % of preoperative SLNs were in the external iliac territory, unusual drainage patterns included the common iliac (19.6 %), para-aortic (10.8 %), and parametrial (6 %) basins.

Conclusions

Our study demonstrates the feasibility and good detection rate of preoperative lymphoscintigraphy, with better detection in younger patients and with the long protocol. The high proportion of SLN basins in unexpected territories is of interest to guide intraoperative detection. Further studies are needed to better evaluate preoperative detection and to assess the contribution of lymphoscintigraphy to intraoperative detection.

Contribution of Lymphoscintigraphy for Sentinel Lymph Node Biopsy in Women with Early Stage Endometrial Cancer: Results of the SENTI-ENDO Study

BACKGROUND

This study was designed to evaluate detection rate and anatomical location of sentinel lymph node (SLN) at lymphoscintigraphy, to compare short and long lymphoscintigraphy protocols, and to correlate lymphoscintigraphic and surgical mapping of SLN in patients with early-stage endometrial cancer (EC).

METHODS

Subanalysis of the prospective multicenter study Senti-endo performed from July 2007 to August 2009. Patients with stage I and II EC received four cervical injections of 0-2 mL of unfiltered technetium sulphur colloid the day before (long protocol) or the morning (short protocol) before surgery. SLN detection used a combined technetium/patent blue labeling technique, and all patients had a systematic bilateral pelvic lymphadenectomy.

RESULTS

A total of 133 patients were enrolled in the study and 118 (94.5 %) underwent a lymphoscintigraphy. Of these 118 patients, 44 (37 %) underwent a short protocol and 66 (56 %) a long protocol (data on lymphoscintigraphy were not available in eight patients). Lymphoscintigraphic detection rate was 74.6 % (34 % for short protocol and 60.2 % for long protocol). No difference in the detection rate was observed according to lymphoscintigraphy protocol (p = 0.22), but a higher number of SLN was noted for the long protocol (p = 0.02). Aberrant drainage was noted on lymphoscintigraphy in 30.5 % of the patients. Paraaortic SLNs were exclusively detected using the long protocol. A poor correlation was noted between short (κ test = 0.24) or long lymphoscintigraphy (κ test = 0.3) protocol and SLN surgical mapping.

CONCLUSIONS

Our study demonstrates that preoperative lymphoscintigraphy allowed a high SLN detection rate and that long lymphoscintigraphy protocol was associated with a higher detection of aberrant drainage especially in the paraaortic area.

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.

Real-time ultrasound and freehand-SPECT. Experiences with sentinel lymph node mapping

Aim of this work is to report first experiences of the feasibility and applicability of a hybrid freehandSPECT/ultrasound (fh-SPECT/US) imaging concept, with regard to SLN imaging, in patients with breast cancer and malignant melanoma.

PATIENTS, METHODS

18 patients with breast cancer or malignant melanoma received standard SLN scintigraphy. Following this, fh-SPECT using declipse®SPECT (SurgicEye, Munich, Germany) was performed, a handheld-gamma camera-based method to visualize activity distribution within a region of interest as a cross-sectional data set. These data were transferred to an ultrasound device and sensor-navigated ultrasound was performed combining fh-SPECT data with ultrasound images, displaying superimposed images. Quality of fh-SPECT and co-registration accuracy was assigned to one of four categories and occurrence of artefacts was assessed.

RESULTS

In 4/18 examinations, there was a no deviation regarding co-registration of both data sets. For 9/18 patients, there was a deviation of <1 cm (mean 0.7±0.3 cm, range 0.3-1.0 cm). For 3/18 patients, a deviation >1 cm was present (mean 1.7±0.3 cm, range 1.5-2.0 cm). In 2/18 examinations no lymph node was found in the region of highest activity. Fh-SPECT reconstruction artifacts occurred in 6/18 examinations.

CONCLUSION

The fusion imaging concept combining SLN information with ultrasound images presented here proves to be feasible and technically successful. However, significant technical limitations were shown in fh-SPECT quality and fusion precision. Subject to technical optimisation of SPECT quality and co-registration, a meaningful contribution to the preoperative planning of lymph node therapy is imaginable. Thus, fundamentally a preoperative histological examination by fh-SPECT/US-guided biopsy is possible.

[Sentinel lymph node in low stage cervical cancers. Current data. Quality assurance. Prospects]

Sentinel node biopsy appears as a promising technique for the assessment of nodal disease in early cervical cancers. Selection of a population with a low risk of nodal metastasis, a minimal training, and simple rules allow a low false negative rate. Sentinel node biopsy provides supplementary information, such as anatomical information (nodes outside of routine lymphadenectomy areas) and histological information (isolated tumors cells and micrometastases).

Distribution pattern of circumflex iliac node distal to the external iliac node metastasis in stage IA to IIA cervical carcinoma

OBJECTIVES

This study aimed to investigate the metastatic rate of circumflex iliac node distal to the external iliac node (CINDEIN) and its associations with clinicopathological factors in patients with stage IA to IIA cervical cancer to determine whether dissection of CINDEIN had a role in surgery of these patients.

METHODS

Six hundred thirty-three patients with the International Federation of Gynecology and Obstetrics stage IA to IIA cervical cancer who underwent radical hysterectomy and pelvic lymphadenectomy were retrospectively reviewed. The metastatic rate and distribution of the pelvic lymph nodes (PLNs) and CINDEINs were analyzed.

RESULTS

The PLN metastatic rate was 25.6% (162 of 633 patients). Sixteen of 162 node-positive patients had CINDEIN metastases. Only 1 patient without PLN metastases had positive CINDEIN nodes. Univariate analysis revealed that other PLNs (including lymph nodes collected from obturator, external iliac, and internal iliac regions) and lymph vascular space involvement were the risk factors of CINDEIN metastases (P < 0.05). Other PLN metastasis (odds ratio, 50.6; 95% confidence interval, 6.6-386.7) was an independent risk factor for metastasis to CINDEIN by binary logistic regression analysis.

CONCLUSIONS

Circumflex iliac node distal to the external iliac node metastases seemed to occur secondarily to widespread PLN metastases. In early stage cervical cancer, removal of the CINDEIN as a routine surgical procedure might be omitted to reduce operation time and minimize surgical morbidity.

The EANM clinical and technical guidelines for lymphoscintigraphy and sentinel node localization in gynaecological cancers

The accurate harvesting of a sentinel node in gynaecological cancer (i.e. vaginal, vulvar, cervical, endometrial or ovarian cancer) includes a sequence of procedures with components from different medical specialities (nuclear medicine, radiology, surgical oncology and pathology). These guidelines are divided into sectione entitled: Purpose, Background information and definitions, Clinical indications and contraindications for SLN detection, Procedures (in the nuclear medicine department, in the surgical suite, and for radiation dosimetry), and Issues requiring further clarification. The guidelines were prepared for nuclear medicine physicians. The intention is to offer assistance in optimizing the diagnostic information that can currently be obtained from sentinel lymph node procedures. If specific recommendations given cannot be based on evidence from original scientific studies, referral is made to "general consensus" and similar expressions. The recommendations are designed to assist in the practice of referral to, and the performance, interpretation and reporting of all steps of the sentinel node procedure in the hope of setting state-of-the-art standards for high-quality evaluation of possible metastatic spread to the lymphatic system in gynaecological cancer. The final result has been discussed by a group of distinguished experts from the EANM Oncology Committee and the European Society of Gynaecological Oncology (ESGO). The document has been endorsed by the SNMMI Board.

Current status of sentinel lymph node mapping in the management of cervical cancer

The status of regional lymph nodes is the most important prognostic factor in early cervical cancer patients. Pelvic lymph node dissections are routinely performed as a part of standard surgical treatment. Systematic pelvic lymphadenectomy is associated with short- and long-term morbidities. This review discusses single components of the sentinel lymph node mapping (SLNM) technique and results of the detection of sentinel lymph nodes. SLNM biopsy performed by an experienced team for small volume tumors (<2 cm) has high specific side detection rate, excellent negative-predictive value and high sensitivity. Uncommon lymphatic drainage has been reported in 15% of cervical cancer patients. There is sufficient data now to suggest that SLNM with 99mTc plus blue dye in the hands of a surgeon with extensive experience should prove to be an important part of individualized cervical cancer surgery and increase the safety of less radical or fertility-sparing surgery.

Value and advantages of preoperative sentinel lymph node imaging with SPECT/CT in cervical cancer

OBJECTIVE

Precise detection of sentinel lymph nodes (SLNs) seems to be a crucial factor for optimized treatment of cervical cancer. We assess the use of single photon emission computed tomography combined with computed tomography (SPECT/CT) as an alternative to lymphoscintigraphy (LSG) for preoperative identification of SLN.

METHODS

This study was performed in a prospective, unicentric setting. Patients with cervical carcinoma were scheduled for surgery and additional SLN labeling by peritumoral injection of 10 MBq technetium-99m-nanocolloid and patent blue. Thirty minutes after injection, LSG and SPECT/CT were carried out. We evaluated the number of SLNs detected intraoperatively in LSG and SPECT/CT and the histologic findings of SLN and non-SLN. Subsequently, we determined the impact of these results on the therapeutic approach.

RESULTS

This represents the largest study about SPECT/CT for SLN detection in cervical cancer so far. Between August 2008 and March 2013, 59 cervical cancer patients underwent intraoperative SLN detection. In addition, 51 of these patients underwent preoperative LSG and SPECT/CT. Imaging with SPECT/CT detected singular SLN at significantly higher rate (47/51, 92.2%) than that with planar LSG (43/51, 84.3%, P = 0.044). Furthermore, SPECT/CT performed better than LSG regarding the total number of detected SLN (SPECT/CT median, 3 [0-18]; LSG median, 2 [0-15]) and detection rates per pelvic side (SPECT/CT 76.9%, LSG 69.2%, P < 0.01). Whenever SLN detection succeeded, histologic evaluation of SLN correctly predicted the lymph node status per patient's side. Using this type of diagnostic approach for lymph node staging, we reached sensitivity of 100% and negative predictive value of 100% at a rate of false-negative results of 0% even in tumors larger than 4 cm.

CONCLUSIONS

Single photon emission computed tomography combined with computed tomography imaging leads to improved rates of SLN detection and better anatomic correlation compared with planar LSG. Thus, intraoperative detection of SLN can be improved by preoperative SPECT/CT imaging. This enhances the clinical value of SLN technique and improves the oncologic safety of SLN concept.

Sentinel lymph node evaluation in women with cervical cancer

Lymph node status is the most important prognosticator of survival in women with early stage cervical cancer. Thus many patients with cervical cancer will undergo pelvic lymphadenectomy as part of the treatment. This procedure is associated with substantial morbidity. Use of the sentinel lymph node technique in women with cervical cancer has the potential to decrease this morbidity. Multiple studies have suggested that sentinel lymph node mapping in these patients is feasible, with excellent detection rates and sensitivity. This review examines the current body of literature about sentinel lymph node biopsy in women with cervical cancer.

Comparison of SPECT-CT results and intraoperative detection of sentinel lymph nodes in endometrial cancer

OBJECTIVES

The aim of the study was to compare the results of single-photon emission computed tomography-computed tomography (SPECT-CT) with those of intraoperative gamma probe detection and assess the clinical utility of SPECT-CT for sentinel lymph node biopsy in endometrial cancer.

MATERIALS AND METHODS

We investigated 70 patients with endometrial cancer who underwent total abdominal hysterectomy, bilateral salpingo-oophorectomy, and sentinel lymph node biopsy (routine pelvic and para-aortic lymphadenectomy was additionally performed in high-risk patients). Tc-99m radiocolloid albumin was injected into the cervix and a blue dye was injected superficially into the fundus.

RESULTS

SPECT-CT revealed hot spots in 64 patients (91.4%). The detection rates were 97.1 and 94.3% using the combined technique and the hand-held gamma probe, respectively. In 19 cases (27.1%) 35 hot spots detected on SPECT-CT were not diagnosed as sentinel lymph nodes (SLNs) during surgery. In each patient with undetected hot spots located in the common iliac or para-aortic regions, hot SLNs were found during surgery in the obturator or external iliac region. In addition, SPECT-CT had detected 88.9% of the SLNs found during surgery. With respect to the 13 cases not detected on SPECT-CT, the hot SLNs had very low activity. Using the combined method, 95.1% of SLNs were found in typical locations (external iliac or obturator nodes). There were two metastatic nodes: one in SLN and one in nonsentinel node.

CONCLUSION

SPECT-CT yields a high SLN detection rate; however, there is significant discrepancy in comparison with intraoperative findings, which limits its clinical utility. In addition, in the majority of cases SLNs are found in typical areas, which means that they can be reliably detected using an intraoperative gamma probe.

SPECT/CT in sentinel node imaging

Sentinel node lymphoscintigraphy and biopsy has become standard practice for lymphatic staging in early-stage breast cancer and melanoma. More recently, sentinel node lymphoscintigraphy has also been used in head and neck squamous cell cancers and other solid tumours. Single photon emission computed tomography/computed tomography (SPECT/CT) is a new tool and this article reviews its potential application in sentinel node imaging. SPECT/CT provides complementary functional and anatomical information and has been shown to be superior to planar imaging in a number of indications. The advantages include more accurate anatomical localization, identification of false positives (due to contamination or spillover from the injection site), reduction in the number of false negatives (visualization of nodes not seen on planar imaging) and alteration of the surgical approach. We thus believe that sentinel lymph node SPECT/CT can provide valuable information before sentinel lymph node biopsy and advocate its use in a range of tumours such as truncal and head and neck melanomas.

Accuracy of intraoperative pathological examination of SLN in cervical cancer

OBJECTIVE

Early cervical cancer patients with pelvic lymph node metastasis do not benefit from radical hysterectomy. Assessment of the SLN status is thus crucial before deciding to perform a radical hysterectomy as opposed to aortic dissection only followed by definitive radiation therapy. Accuracy of frozen section of SLN has been questioned and deserves further investigation.

METHODS

Stage IA-IB1 cervical cancer patients who underwent SLN then full pelvic dissection at the Claudius Regaud Cancer Center in Toulouse, France, were included.

RESULTS

At least one SLN was identified in all 94 patients. Bilateral detection rate was 80.8%. Ectopic drainage area was found in 19 patients (20.2%). Sentinel lymph node involvement was found in 11 patients (11.7%). Sensitivity and NPV of frozen section pathological examination for the detection of macrometastatic disease was 100%, sensitivity for the detection of macro and micrometastatic disease, excluding ITC, was 88.9%, and NPV was 98.8%. Micrometastasis and isolated tumor cells (ITC) undetected at frozen section examination were found in 1 patient (1.06%) and 2 lymph nodes (1.24%), and in 2 patients (2.13%) and 2 lymph nodes (1.24%), respectively. Final pathology sensitivity of SLN was 100% for both macro and micrometastatic disease, including ITC.

CONCLUSION

In our institution, intraoperative frozen examination of SLN accurately predicts the status of pelvic lymph nodes and is effective for selecting intraoperatively the group of patients who benefit from radical hysterectomy. In addition, our results suggest that patients with small tumors and bilateral detection of SLN can be spared full pelvic lymphadenectomy.

Use of SPECT/CT for improved sentinel lymph node localization in endometrial cancer

OBJECTIVE

To assess the usefulness of adding SPECT/CT to planar images for pre-surgical sentinel lymph node (SLN) identification in endometrial cancer (EC), a technique that could have an important clinical impact on the staging, treatment, and prognosis of EC patients.

METHODS

We compared the planar and SPECT/CT lymphoscintigraphic images of 44 patients with high-risk EC who underwent sentinel lymph node procedure (SLN) using an injection technique recently developed at our center known as TUMIR (Transvaginal Ultrasound Myometrial Injection of Radiotracer). 148 MBq (4 mCi) of 99mTc-nanocolloid were injected, guided by transvaginal ultrasound imaging. Planar and SPECT/CT images were performed in all 44 patients.

RESULTS

SLNs were seen on planar images in 32 cases (73%) and in 34 cases (77%) using SPECT/CT. A total of 88 SLNs were depicted by planar lymphoscintigraphy while SPECT/CT visualized a total of 110 SLNs. SPECT/CT changed the assessment of the SLNs visualized in planar lymphoscintigraphy in 26 cases, either by modifying the number and/or the location of the SLNs detected. External iliac chain was the most frequent location of SLN detection (71%) in the 34 cases. Fifteen of these patients (44%) showed para-aortic SLNs. One case had exclusive para-aortic drainage (3%) that was only visualized by SPECT/CT. In another case, SPECT/CT was able to localize the only pelvic metastatic lymph node not visualized by planar images.

CONCLUSIONS

SPECT/CT combined with planar imaging improves preoperative SLN detection and provides valuable anatomic information that enhances the presurgical stage of the SLN technique in endometrial cancer.

The sentinel node technique detects unexpected drainage pathways and allows nodal ultrastaging in early cervical cancer: insights from the multicenter prospective SENTICOL study

BACKGROUND

Sentinel lymph node (SLN) biopsy may improve nodal staging in cervical cancer. The aims of this study are to determine the rate of unusual patterns of cervical lymphatic drainage, to determine the rates of micrometastases and isolated tumor cells (ITCs) in SLNs, and to assess the clinical impact of SLN biopsy.

METHODS

Multicenter prospective study conducted between January 2005 and June 2007 in women undergoing laparoscopic surgery for early cervical cancer. Combined technetium/Patent Blue labeling was used. Lymphoscintigraphy was performed before surgery. SLN location was recorded, and factors associated with location were explored. SLNs underwent step sectioning ± immunohistochemistry.

RESULTS

145 patients were enrolled and 139 included in a modified intention-to-diagnose analysis. Although 80.6 % of SLNs were in external iliac and interiliac areas, 38.2 % of patients had at least one SLN in an unexpected area and 5.1 % had SLNs only in unexpected areas. In unexpected areas, the number of SLNs per patient was not significantly different between lymphoscintigraphy and intraoperative detection (0.79 [0.62-1.02] versus 0.50 [0.37-0.68]; P = 0.096). In expected locations, there were significantly more blue and hot SLNs per patient than blue or hot SLNs (1.70 [1.45-1.99], 0.42 [0.30-0.57], 0.52 [0.39-0.69]). Of 28 metastatic SLNs, 17 contained micrometastases or ITCs. SLN involvement was found only by immunohistochemistry in 39.1 % of patients with positive nodes, and involved SLNs were located in unexpected areas in 17 % of those patients.

CONCLUSIONS

Sentinel lymph node biopsy detects unusual drainage pathways and micrometastases in a substantial proportion of patients, thus improving nodal staging.

Detection of Sentinel Lymph Nodes in Gynecologic Tumours by Planar Scintigraphy and SPECT/CT

Objective: Assess the role of planar lymphoscintigraphy and fusion imaging of SPECT/CT in sentinel lymph node (SLN) detection in patients with gynecologic tumours.

Material and Methods: Planar scintigraphy and hybrid modality SPECT/CT were performed in 64 consecutive women with gynecologic tumours (mean age 53.6 with range 30-77 years): 36 pts with cervical cancer (Group A), 21 pts with endometrial cancer (Group B), 7 pts with vulvar carcinoma (Group C). Planar and SPECT/CT images were interpreted separately by two nuclear medicine physicians. Efficacy of these two techniques to image SLN were compared.

Results: Planar scintigraphy did not image SLN in 7 patients (10.9%), SPECT/CT was negative in 4 patients (6.3%). In 35 (54.7%) patients the number of SLNs captured on SPECT/CT was higher than on planar imaging. Differences in detection of SLN between planar and SPECT/CT imaging in the group of all 64 patients are statistically significant (p<0.05). Three foci of uptake (1.7% from totally visible 177 foci on planar images) in 2 patients interpreted on planar images as hot LNs were found to be false positive non-nodal sites of uptake when further assessed on SPECT/CT. SPECT/CT showed the exact anatomical location of all visualised sentinel nodes.

Conclusion: In some patients with gynecologic cancers SPECT/CT improves detection of sentinel lymph nodes. It can image nodes not visible on planar scintigrams, exclude false positive uptake and exactly localise pelvic and paraaortal SLNs. It improves anatomic localization of SLNs.

Conflict of interest:None declared.

Unusual localizations of sentinel lymph nodes in early stage cervical cancer: a review

OBJECTIVE

The aim of this study was to systematically determine the frequency of unusual localizations of sentinel lymph node in patients with early stage cervical cancer.

METHODS

We performed a comprehensive computer literature search of English and French language studies in human subjects on sentinel node procedures in PUBMED database up to December 2010. For each article two reviewers independently performed data extraction using a standard form to determine the route of unusual lymphatic spread of sentinel procedures in cervical cancer.

RESULTS

According to our search, 83.7% of detected sentinel lymph nodes in patients with cervical cancer were in expected localizations (i.e., external iliac, obturator, internal iliac or interiliac). The unusual localizations were: 6.6% in the common iliac chain, 4.31% parametrial, 1.26% sacral, 2% in the lower para-aortic area and 0.07% in the inguinal chain.

CONCLUSION

The unusual localizations of sentinel lymph nodes impose to the gynecologic surgeons to be able to perform lymph node dissection in all the territories potentially affected.

Automated lymph node detection and classification on breast and prostate cancer SPECT-CT images

We present a novel detection and classification method to process SPECT-CT images representing breast and prostate lymph nodes. Lymph nodes are those nodes that are near the primer tumor and may become cancerous in time, hence their early detection is a key factor for the successful treatment of the patient. Prior methods focus on the visual aid to manually detect the lymph nodes which still makes the process time-consuming. Other solutions segment the lymph nodes only on CT, where the small lymph nodes may not be located accurately. Our solution processed both SPECT and CT data to provide an accurate classification of all SPECT hot spots. The method has been validated on a huge amount of medical data. Results show that our method is a very effective tool to support physicians working with related images in the field of nuclear medicine.