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.

Setting-up a training programme for intraoperative molecular imaging and sentinel node mapping: how to teach? How to learn?

BACKGROUND

The current expansion of image-guided surgery is closely related to the role played by radio-guided surgery in supporting the sentinel node (SN) procedure during more than three decades. The so-called triple approach (lymphoscintigraphy, gamma probe detection and blue dye) was not only essential in the seminal validation of the SN procedure but also a first collective learning effort based on skill transfer and outcome-related evaluation which laid the fundaments to delineate the field of intraoperative molecular imaging (IMI) based on a similar multimodality approach and multidisciplinary practice.

METHODS

These elements are also becoming valid in the current incorporation of SPECT/CT and PET/CT to existing and new protocols of IMI procedures and SN mapping concerning other clinical applications. On the other hand, there is a growing tendency to combine novel modern technologies in an allied role with gamma guidance in the operating room following the development of hybrid tracers and multimodal detection approaches. Against this background, learning initiatives are required for professionals working in this area.

RESULTS

This objective has led to a group of European practitioners with large experience in SN mapping and IMI applications to give shape to a programme made up out of specific learning modules aimed to be used as a conductive thread in peripherical or centralised training instances concerning the topic.

CONCLUSION

The presented work, written as a tutorial review, is placed in an available prior-art context and is primarily aimed at medical and paramedical practitioners as well as at hardware and software developers.

Nuclear medicine contribution to precision surgery in breast cancer

Nuclear medicine has significantly contributed to precision surgery in breast cancer in the past decades. Radioguided surgery (RGS) has enabled sentinel node (SN) biopsy in assessing regional nodal involvement modifying the management of patients with early breast cancer. For the axilla the SN procedure has resulted in fewer complications and better quality of life when compared with axillary lymph node dissection. Originally, SN biopsy principally concerned cT 1-2 tumours without evidence of axillary lymph node metastases. However, in last years SN biopsy is also being offered to patients with large or multifocal tumours, ductal carcinoma in situ, ipsilateral breast cancer relapse, and to patients receiving neoadjuvant systemic treatment (NST) for breast sparing surgery. Parallel to this evolution various scientific associations are trying to homogenise issues such as radiotracer choice, breast injection site, preoperative imaging standardisation and SN biopsy timing in relation to NST as well as management of non-axillary SN metastasis (e.g. internal mammary chain). Additionally, RGS is currently used to accomplish primary breast tumour excision either by intralesional radiocolloid injection or by radioactive iodine seed implantation which is also employed to target metastatic axillary lymph nodes. This latter procedure contributes to manage the node-positive axilla in combination with 18F-FDG PET/CT in an effort to tailor systemic and loco regional treatment.

Clinical impact of molecular breast imaging as adjunct diagnostic modality in evaluation of indeterminate breast abnormalities and unresolved diagnostic concerns

PURPOSE

Improvements in molecular breast imaging (MBI) have increased the use of MBI as adjunct diagnostic modality and alternative to MRI. We aimed to assess the value of MBI in patients with equivocal breast lesions on conventional imaging, especially in terms of its ability to rule out malignancy.

METHODS

We selected patients who underwent MBI in addition to conventional diagnostics due to equivocal breast lesions between 2012 and 2015. All patients underwent digital mammography, target ultrasound and MBI. MBI was performed using a single-head Dilon 6800 gamma camera after administration of 600 MBq 99m Tc-sestamibi. Imaging was reported according to BI-RADS classification and compared with pathology or follow-up of ≥6 months.

RESULTS

Of 226 women included, pathology was obtained in 106 (47%) and (pre)malignant lesions were found in 25 (11%). Median follow-up was 5.4 years (IQR 3.9-7.1). Sensitivity was higher for MBI compared to conventional diagnostics (84% vs. 32%; P  = 0.002), identifying malignancy in 21 and 6 patients, respectively, but specificity did not differ (86% vs. 81%; P  = 0.161). Positive and negative predictive value were 43% and 98% for MBI and 17% and 91% for conventional diagnostics. MBI was discordant with conventional diagnostics in 68 (30%) patients and correctly changed diagnosis in 46 (20%) patients, identifying 15 malignant lesions. In subgroups with nipple discharge ( N  = 42) and BI-RADS 3 lesions ( N  = 113) MBI detected 7 of 8 occult malignancies.

CONCLUSION

MBI correctly adjusted treatment in 20% of patients with diagnostic concerns after conventional work-up, and could rule out malignancy with a high negative predictive value of 98%.

Evaluation of the Hybrid Tracer Indocyanine Green- 99m Tc-Nanocolloid for Sentinel Node Biopsy in Bladder Cancer-A Prospective Pilot Study

RATIONALE

In muscle-invasive bladder cancer (MIBC), lymph node invasion has proven to be an independent predictor of disease recurrence and cancer-specific survival. We evaluated the feasibility of targeting the sentinel node (SN) for biopsy in MIBC patients using the hybrid tracer indocyanine green (ICG)- 99m Tc-nanocolloid for simultaneous radioguidance and fluorescence guidance.

METHODS

Twenty histologically confirmed cN0M0 MIBC patients (mean age, 63.3 years; range, 30-82 years), scheduled for radical cystectomy with SN biopsy and extended pelvic lymph node dissection (ePLND), were prospectively included. Twelve patients were operated on following neoadjuvant chemotherapy. The patients received lymphoscintigraphy as well as SPECT/CT after 4 transurethral injections of ICG- 99m Tc-nanocolloid (mean, 208 MBq; range, 172-229 MBq) around the tumor/scar in the detrusor muscle of the bladder on the day before radical cystectomy. Sentinel node resection was performed under radioguidance and fluorescence guidance.

RESULTS

Nineteen patients could be analyzed. On preoperative imaging, SNs could be identified in 10 patients (53%; mean, 1.6 SN/patient), which revealed drainage pathways outside the ePLND in 20% of the patients. Interesting to note is that 2 patients (10%) with preoperative nonvisualization displayed fluorescent and radioactive SNs during surgery. Location of the primary tumor near the left lateral side of the bladder seemed to be a factor for nonvisualization. Nodal harvesting with ePLND varied among patients (mean, 23.3). Histopathology confirmed tumor-positive nodes in 4 (21%) of all patients. In the 2 patients where an SN could be identified, the ePLND specimens were tumor-negative. All patients with tumor-positive nodes had advanced disease (stage III).

CONCLUSION

Sentinel node biopsy in bladder cancer using the hybrid tracer ICG- 99m Tc-nanocolloid is feasible, and preoperative imaging is predictive for the ability to perform SN biopsy in 83% of the patients who displayed an SN. In patients with a successful preoperative SN mapping using lymphoscintigraphy and SPECT/CT, the intraoperative SN guidance and detection were effective, even outside the ePLND area. As such, this study underscores the critical role that preoperative imaging plays in challenging image-guided surgery applications.

Sentinel Lymph Node Methods in Breast Cancer

Breast cancer is the most frequent cancer diagnosed in women worldwide. Accurate lymph node staging is essential for both prognosis (of early-stage disease) and treatment (for regional control of disease) in patients with breast cancer. The sentinel lymph nodes are the regional nodes that directly drain lymph from the primary tumor. No imaging modality is accurate enough to detect lymph node metastases when a primary breast cancer is at an early stage (I or II), but sentinel lymph node biopsy is a highly reliable method for screening axillary nodes and for identifying metastatic (including micro-metastatic) disease in regional lymph nodes. Despite the widespread use of sentinel lymph node biopsy for early-stage breast cancer, relevant variations have been described regarding practical aspects of the procedure, and some variability has initially been reported regarding the rates of intraoperative sentinel lymph node identification and of false-negative findings, most likely because of differences in the size of the populations being investigated and in lymphatic mapping techniques. Nevertheless, using adequate learning curves and once a multidisciplinary team is experienced with the procedure, improved levels of accuracy are achieved.

Technologic (R)Evolution Leads to Detection of More Sentinel Nodes in Patients with Melanoma in the Head and Neck Region

Sentinel lymph node (SN) biopsy (SNB) has proven to be a valuable tool for staging melanoma patients. Since its introduction in the early 1990s, this procedure has undergone several technologic refinements, including the introduction of SPECT/CT, as well as radioguidance and fluorescence guidance. The purpose of the current study was to evaluate the effect of this technologic evolution on SNB in the head and neck region. The primary endpoint was the false-negative (FN) rate. Secondary endpoints were number of harvested SNs, overall operation time, operation time per harvested SN, and postoperative complications. Methods: A retrospective database was queried for cutaneous head and neck melanoma patients who underwent SNB at The Netherlands Cancer Institute between 1993 and 2016. The implementation of new detection techniques was divided into 4 groups: 1993-2005, with preoperative lymphoscintigraphy and intraoperative use of both a γ-ray detection probe and patent blue (n = 30); 2006-2007, with addition of preoperative road maps based on SPECT/CT (n = 15); 2008-2009, with intraoperative use of a portable γ-camera (n = 40); and 2010-2016, with addition of near-infrared fluorescence guidance (n = 192). Results: In total, 277 patients were included. At least 1 SN was identified in all patients. A tumor-positive SN was found in 59 patients (21.3%): 10 in group 1 (33.3%), 3 in group 2 (20.0%), 6 in group 3 (15.0%), and 40 in group 4 (20.8%). Regional recurrences in patients with tumor-negative SNs resulted in an overall FN rate of 11.9% (group 1, 16.7%; group 2, 0%; group 3, 14.3%; group 4, 11.1%). The number of harvested nodes increased with advancing technologies (P = 0.003), whereas Breslow thickness and operation time per harvested SN decreased (P = 0.003 and P = 0.017, respectively). There was no significant difference in percentage of tumor-positive SNs, overall operation time, and complication rate between the different groups. Conclusion: The use of advanced detection technologies led to a higher number of identified SNs without an increase in overall operation time, possibly indicating an improved surgical efficiency. Operation time per harvested SN decreased; the average FN rate remained 11.9% and was unchanged over 23 y. There was no significant change in postoperative complication rate.

Contemporary update of SPECT tracers and novelties in radioguided surgery: a perspective based on urology

Recent technical advances and implementation of novel radiotracers have further increased the potential of radioguided surgery for a broad variety of malignancies. Indeed, the possibilities for future applications of novel radiotracers in diverse oncological strategies has become more promising than ever. This literature review aims to provide a contemporary update on a selected group of radiotracers and evaluates the usability of radioguided surgery and sentinel node procedures, focusing on most promising advances. For example, the impact of targeted radiotracers on prostate specific membrane antigen (PSMA), CD206 receptor-targeted agents (^99mTc-tilmanocept), and hybrid tracers adding fluorescence to radioguidance (ICG-^99mTc-nanocolloid) as well as targeting hypoxia-induced carbonic anhydrase IX (CAIX) will be covered. Furthermore, future outlooks on the implementation of gold nanoparticles (AuNP's), but also technical advances in improved radiotracer detection by hybrid gamma devices will be discussed.

The EANM practical guidelines for sentinel lymph node localisation in oral cavity squamous cell carcinoma

Purpose

Sentinel lymph node biopsy is an essential staging tool in patients with clinically localized oral cavity squamous cell carcinoma. The harvesting of a sentinel lymph node entails a sequence of procedures with participation of specialists in nuclear medicine, radiology, surgery, and pathology. The aim of this document is to provide guidelines for nuclear medicine physicians performing lymphoscintigraphy for sentinel lymph node detection in patients with early N0 oral cavity squamous cell carcinoma.

Methods

These practice guidelines were written and have been approved by the European Association of Nuclear Medicine (EANM) and the International Atomic Energy Agency (IAEA) to promote high-quality lymphoscintigraphy. The final result has been discussed by distinguished experts from the EANM Oncology Committee, and national nuclear medicine societies. The document has been endorsed by the Society of Nuclear Medicine and Molecular Imaging (SNMMI).

These guidelines, together with another two focused on Surgery and Pathology (and published in specialised journals), are part of the synergistic efforts developed in preparation for the “2018 Sentinel Node Biopsy in Head and Neck Consensus Conference”.

Conclusion

The present practice guidelines will help nuclear medicine practitioners play their essential role in providing high-quality lymphatic mapping for the care of early N0 oral cavity squamous cell carcinoma patients.

Outcome of sentinel lymph node biopsy in patients with clinically non-metastatic renal cell carcinoma

OBJECTIVE

To investigate the rate of occult SN metastases, oncological outcome, and association of recurrence with the pattern of lymphatic tumour drainage in RCC.

MATERIALS AND METHODS

A pooled RCC sub-group analysis was conducted of secondary endpoints from a published feasibility and a phase II prospective single-arm SN study to investigate oncological outcome. Patients with cT1-3 (<10 cm) cN0M0 RCC of any sub-type were enrolled. After intratumoural injection of Tc^99m nanocolloid, pre-operative imaging of SNs with SPECT/CT was followed by (partial) nephrectomy with SN and regional lymph node dissection using a γ-probe. The patients were followed with a risk-adapted surveillance programme. Endpoints of the studies were analysed using Cox proportional hazard models.

RESULTS

Sixty-six RCC patients were included. Two patients (3%, 95% CI =0.5-11%) had occult SN metastases and remained free of disease at 57 and 72 months. Ten patients (15%, 95% CI =7-26%) developed recurrences, and four (6%, 95% CI =2.3-14.5%) had died of disease at a median follow-up of 57 months (IQR =18-72 months). Occurrence of distant metachronous metastases were associated with tumour size (HR =1.39, p = 0.02), pT stage (HR =6.83, p < 0.01 for comparison T1 vs T3/4), Grade 3/4 (HR =8.38, p = 0.05 for comparison 1/2 vs 3/4) and interaortocaval sentinel lymph node location (HR =10.52, p = 0.03 for comparison yes vs no).

CONCLUSIONS

The rate of occult metastatic SN is low, but long disease-free survival (DFS) was observed in two patients with occult SN metastases. We hypothesize an interaortocaval lymphatic route in thoracic recurrences. Evaluation of the prognostic and therapeutic role of sentinel lymph node biopsy (SLNB) requires a clinical trial in high-risk RCC.

An analysis of SPECT/CT non-visualization of sentinel lymph nodes in renal tumors

Background

Sentinel lymph node biopsy (SLNB) after intratumoral injection of ^99mTc labeled nanocolloid and imaging with scintigraphy and SPECT/CT in renal tumors is feasible. However, sentinel lymph node (SN) non-detection rate with scintigraphy and SPECT/CT is high. The aim of the study was to determine factors affecting non-visualization (NV) of SN imaging in renal tumors. Seventy-eight patients with cT1–3 renal tumors received intratumoral injection of 225 MBq ^99mTc-labeled nanocolloid 1 day before (partial) nephrectomy. Radiotracer injection was followed by anterioposterior and lateral scintigraphy in combination with SPECT/CT 20 min and 2–4 h after. Surgical treatment of the tumor with sentinel lymph node biopsy by aid of γ-probe and-camera was performed the next day. Scintigraphy and SPECT/CT images were evaluated and patient, tumor, and procedure characteristics were collected for 73 eligible patients used in uni- and multivariable analysis of a potential association with NV.

Results

A total of 80 (mean 1.1, IQR 0–2, max 6) sentinel lymph nodes in 46 patients were detected with scintigraphy and SPECT/CT. Preoperative visualization rate and intraoperative detection rate was 63% [95% CI 50–73%] and 61% [95% CI 49–72%], respectively. In uni- and multivariable analysis, the only factor associated with non-visualization was age, showing higher odds of non-visualization with higher age.

Conclusion

Our study demonstrated that non-visualization of SNs in renal tumors is relatively high and is associated with patient age. Furthermore, kidneys and also its tumors are highly vascularized which may cause a wash-out effect that could be identified with decreased kidney-liver ratios. However, in our data, the effect was statistically inconclusive. Further studies are needed to improve visualization and standardize the procedure of SLNB in renal tumors. The percentage of NV limits the use of SLNB for research and clinical purposes in renal cancer.

Electronic supplementary material

The online version of this article (10.1186/s13550-018-0460-y) contains supplementary material, which is available to authorized users.

Radiomics in vulvar cancer: first clinical experience using 18F-FDG PET/CT images

This study investigates whether radiomic features derived from preoperative positron emission tomography (PET) images could predict both tumor biology and prognosis in women with invasive squamous cell carcinoma of the vulva. Methods: Patients were retrospectively included when they had a unifocal primary cancer of ≥ 2.6 cm in diameter, had received a preoperative 18F-fluorodeoxyglucose (18F-FDG) PET/computed tomography (CT) scan followed by surgery and had at least six months of follow-up data. 18F-FDG-PET images were analyzed by semi-automatically drawing on the primary tumor in each PET image, followed by the extraction of 83 radiomic features. Unique radiomic features were identified by principal component analysis (PCA), after which they were compared with histopathology using non-pairwise group comparison and linear regression. Univariate and multivariate Cox regression analyses were used to correlate the identified features with progression-free survival (PFS) and overall survival (OS). Survival curves were estimated using the Kaplan-Meier method. Results: Forty women were included. PCA revealed four unique radiomic features, which were not associated with histopathologic characteristics such as grading, depth of invasion, lymph-vascular space invasion and metastatic lymph nodes. No statistically significant correlation was found between the identified features and PFS. However, Moran's I, a feature that identifies global spatial autocorrelation, was correlated with OS (P = 0.03). Multivariate Cox regression analysis showed that extracapsular invasion of the metastatic lymph nodes and Moran's I were independent prognostic factors for PFS and OS. Conclusion: Our data show that PCA is usable to identify specific radiomic features. Although the identified features did not correlate strongly with tumor biology, Moran's I was found to predict patient prognosis. Larger studies are required to establish the clinical relevance of the observed findings.

Experimental validation of absolute SPECT/CT quantification for response monitoring in breast cancer

PURPOSE

Recent developments in iterative image reconstruction enable absolute quantification of SPECT/CT studies by incorporating compensation for collimator-detector response, attenuation, and scatter as well as resolution recovery into the reconstruction process (Evolution; Q.Metrix package; GE Healthcare, Little Chalfont, UK). The aim of this experimental study is to assess its quantitative accuracy for potential clinical ^99m Tc-sestamibi (MIBI)-related SPECT/CT application in neoadjuvant chemotherapy response studies in breast cancer.

METHODS

Two phantoms were filled with MIBI and acquired on a SPECT/CT gamma camera (Discovery 670 Pro; GE Healthcare), that is, a water cylinder and a NEMA body phantom containing six spheres that were filled with an activity concentration reflecting clinical MIBI uptake. Subsequently, volumes-of-interest (VOI) of each sphere were drawn (semi)automatically on SPECT using various isocontour methods or manually on CT. Finally, prone MIBI SPECT/CT scans were acquired 5 and 90 min p.i. in a locally advanced breast cancer patient.

RESULTS

Activity concentration in the four largest spheres converged after nine iterations of evolution. Depending on the count statistics, the accuracy of the reconstructed activity concentration varied between -4.7 and -0.16% (VOI covering the entire phantom) and from 6.9% to 10% (8.8 cm ⌀ cylinder VOI placed in the center of the phantom). Recovery coefficients of SUV_max were 1.89 ± 0.18, 1.76 ± 0.17, 2.00 ± 0.38, 1.89 ± 0.35, and 0.90 ± 0.26 for spheres with 37, 28, 22, 17, and 13 mm ⌀, respectively. Recovery coefficients of SUV_mean were 1.07 ± 0.06, 1.03 ± 0.09, 1.17 ± 0.21, 1.10 ± 0.20, and 0.52 ± 0.14 (42% isocontour); 1.10 ± 0.07, 1.02 ± 0.09, 1.13 ± 0.19, 1.06 ± 0.19, and 0.51 ± 0.13 (36% isocontour with local background correction); and 0.96, 1.09, 1.03, 1.03, and 0.29 (CT). Patient study results were concordant with the phantom validation.

CONCLUSIONS

Absolute SPECT/CT quantification of breast studies using MIBI seems feasible (<17% deviation) when a 42% isocontour is used for delineation for tumors of at least 17 mm diameter. However, with tumor shrinkage, response evaluation should be handled with caution, especially when using SUV_max .

Lymphatic Drainage from Renal Tumors In Vivo: A Prospective Sentinel Node Study Using SPECT/CT Imaging

PURPOSE

Lymphatic drainage from renal tumors is unpredictable. In vivo drainage studies of primary lymphatic landing sites may reveal the variability and dynamics of lymphatic connections. The purpose of this study was to investigate the lymphatic drainage pattern of renal tumors in vivo with single photon emission/computerized tomography after intratumor radiotracer injection.

MATERIALS AND METHODS

We performed a phase II, prospective, single arm study to investigate the distribution of sentinel nodes from renal tumors on single photon emission/computerized tomography. Patients with cT1-3 (less than 10 cm) cN0M0 renal tumors of any subtype were enrolled in analysis. After intratumor ultrasound guided injection of 0.4 ml ^99mTc-nanocolloid we performed preoperative imaging of sentinel nodes with lymphoscintigraphy and single photon emission/computerized tomography. Sentinel and locoregional nonsentinel nodes were resected with a γ probe combined with a mobile γ camera. The primary study end point was the location of sentinel nodes outside the locoregional retroperitoneal templates on single photon emission/computerized tomography. Using a Simon minimax 2-stage design to detect a 25% extralocoregional retroperitoneal template location of sentinel nodes on imaging at α = 0.05 and 80% power at least 40 patients with sentinel node imaging on single photon emission/computerized tomography were needed.

RESULTS

Of the 68 patients 40 underwent preoperative single photon emission/computerized tomography of sentinel nodes and were included in primary end point analysis. Lymphatic drainage outside the locoregional retroperitoneal templates was observed in 14 patients (35%). Eight patients (20%) had supradiaphragmatic sentinel nodes.

CONCLUSIONS

Sentinel nodes from renal tumors were mainly located in the respective locoregional retroperitoneal templates. Simultaneous sentinel nodes were located outside the suggested lymph node dissection templates, including supradiaphragmatic sentinel nodes in more than a third of the patients.

Advances in radioguided surgery in oncology

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

Monitoring tumor response to neoadjuvant chemotherapy using MRI and 18F-FDG PET/CT in breast cancer subtypes

Purpose

To explore guidelines on the use of MRI and PET/CT monitoring primary tumor response to neoadjuvant chemotherapy (NAC), taking breast cancer subtype into account.

Materials and methods

In this prospective cohort study, 188 women were included with stages II and III breast cancer. MRI and ¹⁸F-FDG-PET/CT were acquired before and during NAC. Baseline pathology was assessed from tumor biopsy. Tumors were stratified into HER2-positive, ER-positive/HER2-negative (ER-positive), and ER-negative/PR-negative/HER2-negative (triple-negative) subtypes, and treated according to subtype. Primary endpoint was pathological complete response (pCRmic) defined as no or only small numbers of scattered invasive tumor cells. We evaluated imaging scenarios using MRI only, PET/CT only, and combinations.

Results

pCRmic was found in 35/46 (76.1%) of HER2-positive, 11/87 (12.6%) of ER-positive, and 31/55 (56.4%) of triple-negative tumors. For HER2-positive tumors, MRI yielded the strongest predictor (AUC: 0.735; sensitivity 36.2%), outperforming PET/CT (AUC: 0.543; p = 0.04), and with comparable results to combined imaging (AUC: 0.708; p = 0.213). In ER-positive tumors, the combination of MRI and PET/CT was slightly superior (AUC: 0.818; sensitivity 55.8%) over MRI alone (AUC: 0.742; p = 0.117) and PET/CT alone (AUC: 0.791). However, even though relatively large numbers of ER-positive tumor patients were included, no significant differences were yet found. For triple-negative tumors, MRI (AUC: 0.855; sensitivity 45.4%), PET/CT (AUC: 0.844; p = 0.220) and combined imaging (AUC: 0.868; p = 0.213) yielded comparable results.

Conclusions

For HER2-positive tumors, MRI shows significant advantage over PET/CT. For triple-negative tumors, comparable results were seen for MRI, PET/CT and combined imaging. For ER-positive tumors, combining MRI with PET/CT may result in optimal response monitoring, although not yet significantly.

Contribution of SPECT/CT for sentinel node localization in patients with ipsilateral breast cancer relapse

Background

In recent years repeat sentinel node (SN) biopsy has been proven to be feasible in local breast cancer recurrence (LBCR). However, in these patients SNs outside the ipsilateral axilla are frequently observed. This study evaluates the contribution of SPECT/CT for SN localization and surgical adjustment in LBCR patients.

Methods

SN biopsy was performed in 122 LBCR patients (median age 60.5 years, range 24–87), enrolled from August 2006 to July 2015. Median disease-free time lapse was 109.5 months (range 9–365). Axillary lymph node dissection (ALND) had previously been performed in 55 patients, SN biopsy in 44, both techniques in 13 and fine-needle aspiration in 10. Primary breast cancer treatment included radiotherapy in 104 patients (85.3 %) and chemotherapy in 40 (32.8 %). Preoperative lymphatic mapping, using planar scintigraphy (PS) and SPECT/CT included report of SN location according to lymph node territory. In case of a territorial PS-SPECT/CT mismatch, surgery was adjusted according to SPECT/CT findings.

Results

SPECT/CT SN visualization rate was higher than PS (53.3 % vs. 43.4 %, p n.s.) with, in total, 19 additional SN (118 vs. 99, p n.s.). PS-SPECT/CT territory mismatch, found in 60 % (39/65) of patients with SN visualization, led to surgical adjustment in 21.3 % (26/122) of patients. The SN procedure was finally performed in 104 patients resulting in a 65.7 % surgical retrieval rate with a total of 132 removed SNs (1.86/patient). SN metastases were found in 17/71 patients (23.9 %), in 16 of them (94 %) in ipsilateral basins outside the axilla or in the contralateral axilla.

Conclusion

Using SPECT/CT there is a trend to visualize more SNs in LBCR, providing at the same time important anatomical information to adjust intraoperative SN procedures. The addition of SPECT/CT to the standard imaging protocol may lead to better staging mainly in patients presenting drainage outside the ipsilateral axilla.

Tumor heterogeneity on (18)F-FDG-PET/CT for response monitoring in non-small cell lung cancer treated with erlotinib

Response monitoring using fluorodeoxyglucose positron emission tomography acquired together with low dose computed tomography (FDG-PET/CT) textural features has potential in targeted treatment with erlotinib in non-small cell lung cancer (NSCLC) patients. Patients with substantial decrease of metabolic activity during erlotinib treatment will probably benefit from continued treatment. However, various aspects of the method (quantification tools, cut-off values, etc.) need to be standardized before the software becomes widely available in a similar manner as standardized uptake value (SUV) measurements. Heterogeneity on FDG-PET/CT opened an additional window for innovation but simultaneously a new challenge for molecular hybrid imaging.

The use of SPECT/CT for anatomical mapping of lymphatic drainage in vulvar cancer: possible implications for the extent of inguinal lymph node dissection

PURPOSE

To determine the lymphatic drainage pattern using SPECT/CT in clinically node-negative (cN0) patients with vulvar cancer, and to evaluate the possible implications for the extent of inguinal lymph node dissection.

METHODS

A total of 83 patients with vulvar cancer scheduled for sentinel node (SN) biopsy were injected peritumorally with radioactive nanocolloid particles followed by lymphoscintigraphy and SPECT/CT for anatomical localization. The SN and higher-echelon nodes on SPECT/CT were located in different zones in the groin and pelvic region. The groin was divided into five zones according to Daseler et al.: four zones obtained by drawing two perpendicular lines over the saphenofemoral junction and one zone directly overlying this junction. The nodes in the pelvic region were classified into three zones: external iliac/obturator, the common iliac and the paraaortic zones.

RESULTS

A total of 217 SNs and 202 higher-echelon nodes were localized on SPECT/CT. All SNs were located in the five zones according to Daseler et al.: 149 (69%) in the medial superior region, 31 (14%) in the medial inferior region, 22 (10%) in the central region, 14 (6.5%) in the lateral superior region and only 1 (0.5%) in the lateral inferior region. The higher-echelon nodes were located both in the groin (15%) and in the pelvic region (85%).

CONCLUSION

In patients with cN0 vulvar cancer, lymphatic drainage occurs predominantly to the medial regions of the groin. Drainage to the lateral inferior region of the groin is only incidental and in SN-positive patients this zone might be spared in subsequent extended lymph node dissection. This may lead to a decrease in the morbidity associated with this procedure. SPECT/CT is able to personalize lymphatic mapping, providing detailed information about the number and anatomical location of SNs for adequate surgical planning in the groin.

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.

Heading toward radioactive seed localization in non-palpable breast cancer surgery? A meta-analysis

Wire-guided localization is the most commonly used technique for intraoperative localization of non-palpable breast cancer. Radioactive seed localization (RSL) is becoming more popular and seems to be a reliable alternative for intraoperative lesion localization. The purpose of the present meta-analysis was to evaluate the use of RSL. Primary study outcomes were irradicality and re-excision rates. In total 3168 patients were included. The clinical adaptation shows growing confidence in RSL and further growth is expected.

Timing of metabolic response monitoring during erlotinib treatment in non-small cell lung cancer

The purpose of this study was to prospectively evaluate the timing of metabolic response monitoring with (18)F-FDG PET of (neoadjuvant) erlotinib treatment in patients with early-stage non-small cell lung cancer.

METHODS

This study was designed as an open-label phase II trial performed in 4 hospitals in The Netherlands. Patients received preoperative erlotinib (150 mg) once daily for 3 wk. Response evaluation was performed after 4-7 d and at 3 wk with (18)F-FDG PET/CT scans. Tumor (18)F-FDG uptake and changes were measured as standardized uptake values (SUVs). The metabolic response was classified on the basis of European Organization for Research and Treatment of Cancer criteria (>25% decrease in the maximum SUV) and was compared with histopathologic regression as observed in the resection specimen.

RESULTS

From December 2006 to November 2010, 60 patients with non-small cell lung cancer eligible for surgical resection were enrolled in this study. For 43 patients (18 men and 25 women), baseline (18)F-FDG PET/CT scans as well as both monitoring scans and histopathologic response monitoring were available. A partial metabolic response on (18)F-FDG PET/CT scans was observed for 10 patients (23%) after 1 wk and for 14 patients (33%) after 3 wk. Histopathologic examination revealed regression (necrosis of >50%) in 11 patients (26%). In these patients, the maximum SUV decreased by a mean of 17% within 1 wk and a mean of 31% at 3 wk. Seven patients were identified as responders within 1 wk.

CONCLUSION

Response monitoring with (18)F-FDG PET/CT within 1 wk after the start of erlotinib treatment identified approximately 64% of histopathologic responders on the basis of European Organization for Research and Treatment of Cancer criteria.

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 (^99mTc-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 (¹²⁵I) 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 ¹²⁵I seed was primarily localised using freehand SPECT and subsequently verified by conventional US in order to inject the ^99mTc-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 ^99mTc-nanocolloid injection depot and the ¹²⁵I seed. In retrospect, a group of 21 patients with US-guided ^99mTc-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 ¹²⁵I seeds (34 patients), the average difference between the ¹²⁵I seed and the centre of the ^99mTc-nanocolloid injection depot was 10.9 ± 6.8 mm. In the retrospective study, the average distance between the ¹²⁵I seed and the centre of the ^99mTc-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 ^99mTc-nanocolloid administration in patients with non-palpable breast cancer with previously implanted ¹²⁵I seed is feasible. This technique may improve daily clinical logistics, reducing the workload of the radiology department.

Accuracy of 18F-FDG PET/CT for primary tumor visualization and staging in T1 breast cancer

BACKGROUND

The aim of this study was to assess the accuracy of 18F-FDG PET/CT in T1 breast cancer regarding visualization of the primary tumor and the detection of locoregional and distant metastases.

METHODS

Sixty-two women with invasive T1 breast cancer underwent a PET/CT. Image acquisition of the thorax was done in prone position with hanging breasts, followed by whole-body scanning in supine position. Primary tumor FDG uptake was evaluated and compared with clinical and histopathological characteristics. Presence of locoregional and distant metastases was assessed and compared with conventional imaging procedures.

RESULTS

The primary tumor was visible with PET/CT in 54 (87%) of 62 patients, increasing from 59% (10/17) in tumors ≤ 10 mm to 98% (44/45) in tumors over 10 mm. All triple negative and HER2-positive tumors and 40/48 (83%) ER-positive/HER2-negative tumors were visualized. Sensitivity and specificity of PET/CT in the detection of axillary metastases were 73% and 100%, respectively. PET/CT depicted periclavicular nodes in two patients. Of 12 distant lesions, one was confirmed to be a lung metastasis, three were false positive, and eight were new primary proliferative lesions.

CONCLUSION

Using optimal imaging acquisition, the majority of T1 breast carcinomas can be visualized with PET/CT. Specificity in the detection of axillary metastases is excellent, but sensitivity appears to be limited. Additional whole body imaging has a low yield in this specific patient group.

A hybrid radioactive and fluorescent tracer for sentinel node biopsy in penile carcinoma as a potential replacement for blue dye

BACKGROUND

Sentinel node (SN) biopsy in penile cancer is typically performed using a combination of radiocolloid and blue dye. Recently, the hybrid radioactive and fluorescent tracer indocyanine green (ICG)-(99m)Tc-nanocolloid was developed to combine the beneficial properties of both radio-guidance and fluorescence imaging.

OBJECTIVE

To explore the added value of SN biopsy using ICG-(99m)Tc-nanocolloid in patients with penile carcinoma.

DESIGN, SETTING, AND PARTICIPANTS

Sixty-five patients with penile squamous cell carcinoma were prospectively included (January 2011 to December 2012). Preoperative SN mapping was performed using lymphoscintigraphy and single-proton emission computed tomography supplemented with computed tomography (SPECT/CT) after peritumoural injection of ICG-(99m)Tc-nanocolloid. During surgery, SNs were initially approached using a gamma probe, followed by patent blue dye and/or fluorescence imaging. A portable gamma camera was used to confirm excision of all SNs.

SURGICAL PROCEDURE

Patients underwent SN biopsy of the cN0 groin and treatment of the primary tumour.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

The number and location of preoperatively identified SNs were documented. Intraoperative SN identification rates using radio- and/or fluorescence guidance were assessed and compared with blue dye. Statistical evaluation was performed using a two-sample test for equality of proportions with continuity correction.

RESULTS AND LIMITATIONS

Preoperative imaging after injection of ICG-(99m)Tc-nanocolloid enabled SN identification in all patients (a total of 183 SNs dispersed over 119 groins). Intraoperatively, all SNs identified by preoperative SN mapping were localised using combined radio-, fluorescence-, and blue dye guidance. Fluorescence imaging enabled visualisation of 96.8% of SNs, while only 55.7% was stained by blue dye (p<0.0001). The tissue penetration of the fluorescent signal, and the rapid flow of blue dye limited the detection sensitivity. A tumour-positive SN was found in seven patients.

CONCLUSIONS

ICG-(99m)Tc-nanocolloid allows for both preoperative SN mapping and combined radio- and fluorescence-guided SN biopsy in penile carcinoma patients and significantly improves optical SN detection compared with blue dye.

Contemporary management of regional nodes in penile cancer-improvement of survival?

PURPOSE

The management of regional nodes of penile squamous cell carcinoma has changed with time due to improved knowledge about diagnosis and treatment. To determine whether changes in the treatment of regional nodes have improved survival, we compared contemporary 5-year cancer specific survival of patients with squamous cell carcinoma of the penis with that of patients in previous cohorts.

MATERIALS AND METHODS

In an observational cohort study of 1,000 patients treated during 56 years 944 were eligible for analysis. Tumors were staged according to the 2009 TNM classification, and patients were divided into 4 cohorts of 1956 to 1987, 1988 to 1993, 1994 to 2000 and 2001 to 2012, reflecting changes in clinical practice regarding regional nodes. Kaplan-Meier survival curves with the log rank test and Cox proportional hazards modeling were used to examine trends in 5-year cancer specific survival.

RESULTS

The 5-year cancer specific survival of patients with cN0 disease treated between 2001 and 2012 was 92% compared to 89% (1994 to 2000), 78% (1988 to 1993) and 85% (1956 to 1987). The 5-year cancer specific survival improved significantly since 1994, the year dynamic sentinel node biopsy was introduced, at 91% (1994 to 2012) vs 82% (1956 to 1993) (p = 0.021). This conclusion still holds after adjustment for pathological T stage and grade of differentiation (HR 2.46, p = 0.01). Extranodal extension, number of tumor positive nodes and pelvic involvement in node positive (pN+) cases were associated with worse 5-year cancer specific survival.

CONCLUSIONS

Despite less surgery being performed on regional nodes, 5-year cancer specific survival has improved in patients with cN0 disease. The number of tumor positive nodes, extranodal extension and pelvic involvement were highly associated with worse cancer specific survival in patients with pN+ disease. In this group other treatment strategies are needed as no improvement was observed.

FDG PET/CT during neoadjuvant chemotherapy may predict response in ER-positive/HER2-negative and triple negative, but not in HER2-positive breast cancer

BACKGROUND

Response monitoring with MRI during neoadjuvant chemotherapy (NAC) in breast cancer is promising, but knowledge of breast cancer subtype is essential. The aim of the present study was to evaluate the relevance of breast cancer subtypes for monitoring of therapy response during NAC with 18F-FDG PET/CT.

METHODS

Evaluation included 98 women with stages II and III breast cancer. PET/CTs were performed before and after six or eight weeks of NAC. FDG uptake was quantified using maximum standardized uptake values (SUVmax). Tumors were divided into three subtypes: HER2-positive, ER-positive/HER2-negative, and triple negative. Tumor response at surgery was assessed dichotomously (presence or absence of residual disease) and ordinally (breast response index, representing relative change in tumor stage). Multivariate regression and receiver operating characteristic (ROC) analyses were employed to determine associations with pathological response.

RESULTS

A (near) complete pathological response was seen in 19 (76%) of 25 HER2-positive, 7 (16%) of 45 ER-positive/HER2-negative, and 20 (71%) of 28 triple negative tumors. Multivariate regression of pathological response indicated a significant interaction between change in FDG uptake and breast cancer subtype. The area under the ROC curve was 0.35 (0.12-0.64) for HER2-positive, 0.90 (0.76-1.00) for ER-positive/HER2-negative, and 0.96 (0.86-1.00) for triple negative tumors. We found no association between age, stage, histology, or baseline SUVmax and pathological response.

CONCLUSION

Response monitoring with PET/CT during NAC in breast cancer seems feasible, but is dependent on the breast cancer subtype. PET/CT may predict response in ER-positive/HER2-negative and triple negative tumors, but seems less accurate in HER2-positive tumors.

Tumor Response and Toxicity of Neoadjuvant Erlotinib in Patients With Early-Stage Non–Small-Cell Lung Cancer

Purpose

The development of targeted therapy has introduced new options to improve treatment outcome in selected patients. The objective of this prospective study was to investigate the safety of preoperative erlotinib treatment and the (in vivo) response in patients with early-stage resectable non–small-cell lung cancer (NSCLC).

Patients and Methods

This study was designed as an open-label phase II trial, performed in four hospitals in the Netherlands, according to a Simon's minimax two-stage procedure. Initially, operable patients with early-stage NSCLC (n = 15) were entered from an enriched population (never-smoker, female sex, nonsquamous histology, or Asian ethnicity); thereafter, unselected patients were included to a total of N = 60. Patients received preoperative erlotinib 150 mg once daily for 3 weeks. Response to treatment was evaluated using [18F] fluorodeoxyglucose positron emission tomography (PET) and computed tomography (CT) scans during treatment and histologic examination of the resection specimen. Primary end points were toxicity and pathologic response.

Results

Sixty patients were included. Seven patients stopped treatment prematurely (12%). Skin toxicity was present in 37 patients (62%), and diarrhea was present in 21 patients (35%). PET evaluation revealed metabolic response (> 25% standardized uptake value decrease) in 16 patients (27%); CT evaluation using Response Evaluation Criteria in Solid Tumors (RECIST) showed response in three patients (5%). At surgery, no unexpected complications occurred. Pathologic examination showed more than 50% necrosis in 14 patients (23%), of whom three (5%) had more than 95% tumor necrosis. The response rate in the enriched population was 34% (10 of 29 patients).

Conclusion

According to predefined criteria, neoadjuvant erlotinib has low toxicity and sufficient activity to deserve further testing in future studies in an enriched population.