The predictive value of single-photon emission computed tomography/computed tomography for sentinel lymph node localization in head and neck cutaneous malignancy

Surgical Management of Melanoma: Advances and Updates

PURPOSE OF REVIEW

To review and update surgeons about the evolving complexities in the surgical management of melanoma including lymph node staging and treatment.

RECENT FINDINGS

Primary resection with adequate margins continues to be the standard of care for localized cutaneous melanoma. Sentinel lymph node biopsy is confirmed to be a powerful tool due to its prognostic value and informative guidance for adjuvant treatments and surveillance. Due to the lack of benefit in melanoma-specific survival and distant metastasis-free survival, completion lymph node dissection is not performed routinely after a positive sentinel lymph node biopsy. Neoadjuvant systemic treatment approaches for advanced loco-regional disease show promise in phase I and II clinical trial data, and phase III studies. The surgical management of cutaneous melanoma continues to evolve with further de-escalation of the extent of excision of primary melanomas and the management of lymph node disease.

Sentinel Node Biopsy for Nonmelanoma Skin Cancer of the Head and Neck

Sentinel lymph node biopsy has the potential to impact regional control and survival for high-risk cutaneous malignancy. The outcome of sentinel lymph node biopsy is a potential guide for treatment and surveillance. The population of high-risk nonmelanoma patients that will benefit from sentinel lymph node biopsy remains to be determined. Any cutaneous malignancy with a greater than 10% risk of occult metastasis should be considered for sentinel lymph node biopsy or active surveillance. Localized cutaneous squamous cell carcinoma lesions with multiple high-risk features and nearly all patients with localized Merkel cell carcinoma should be considered for sentinel lymph node biopsy.

Application of imaging in lymphedema surgical therapies

Lymphedema is a chronic, progressive disease caused by primary or secondary reasons. It is currently uncurable and conservative compression therapy is generally applied. Lymphovenous anastomosis and vascularized lymph node transfer (VLNT) are two main surgical treatment that are used in addition to conservative therapy. Lymphovenous anastomosis involves the anastomosing remaining functional lymphatic vessels to vein. When the lymphatic vessels are greatly damaged and in no case can they be used for anastomosis, VLNT provide the affected area with lymph nodes from elsewhere to restore the drainage function. During all these procedures, a clear image to identify related lymphatic structures and venous vessels can be greatly useful for preoperative planning, intraoperative navigation, and postoperative evaluation. Lymphoscintigraphy used to be the gold standard in evaluating lymphedema and mapping lymphatic systems. But due to the downside of radiation, invasive operation and complication, other modalities are gaining attention. In this article, we reviewed the application of Indocyanine green (ICG) lymphography, ultrasound, magnetic resonance lymphography (MRL), and single-photon emission computed tomography-computed tomography (SPECT-CT) in the field of surgical therapy in lymphedema.

Individualized Prophylactic Neck Irradiation in Patients with cN0 Head and Neck Cancer Based on Sentinel Lymph Node(s) Identification: Definitive Results of a Prospective Phase 1-2 Study

PURPOSE

This prospective, nonrandomized, interventional phase 1-2 study investigated the individualization of elective node irradiation in clinically N0 head and neck squamous cell carcinoma by sentinel lymph node (SLN) mapping with single-photon emission computed tomography/computed tomography (SPECT/CT) and its impact on tumor control and radiation-related toxicity.

METHODS AND MATERIALS

Forty-four patients with clinically N0 head and neck squamous cell carcinoma treated with definitive (chemo-)radiation therapy were imaged with SPECT/CT after ^99mTc nanocolloid injection around the tumor. The neck levels containing up to the 4 hottest SLNs were selected for prophylactic irradiation. A comparative virtual planning was performed with the selection of neck levels based on the current international guidelines. Regional control was monitored as a function of the selected volume. Dosimetric data for the organs at risk were compared between the plans. Normal tissue complication probability (NTCP) rates were derived for xerostomia, dysphagia, and hypothyroidism to predict the clinical benefit and correlated to quality-of-life (QoL) assessments at 6 months.

RESULTS

Sixteen percent of patients presented unpredicted lymphatic drainage, and 48% drained unilaterally. The nodal clinical target volume based on lymphoscintigraphy was smaller than the nodal clinical target volume based on international guidelines by a factor of 2 (P < .0001). After a median follow-up of 46 months, only 1 patient experienced a regional relapse in a nonirradiated area. Significant median dose reductions to organs at risk were observed, particularly to contralateral salivary glands in patients with unilateral drainage (14.6-28.1 Gy) and to the thyroid gland in all patients (22.4-48.9 Gy). Median NTCP reductions were observed for xerostomia (0.3% to 13.7%), dysphagia (1.7% to 10.8%), and hypothyroidism (14.0% to 36.1%). QoL at 6 months was improved, particularly in patients irradiated unilaterally.

CONCLUSIONS

Neck SLN mapping with SPECT/CT individualizes and reduces the elective nodal target volumes without compromising the regional control. The NTCP rates were reduced and favorable QoL were observed in all patients, particularly in the case of unilateral irradiation.

Value of SPECT/CT for Sentinel Lymph Node Localization in the Parotid and External Jugular Chain

OBJECTIVE

Preoperative single-photon emission computed tomography/computed tomography (SPECT/CT) imaging may aid in the localization of sentinel lymph nodes (SLNs) in cutaneous head and neck malignancy and has been rigorously evaluated for deep cervical lymph nodes. The purpose of this study was to assess the sensitivity, specificity, and positive predictive value (PPV) of SPECT/CT for preoperative localization of nodal basins superficial to the sternocleidomastoid muscle, with comparison to deep nodal basins of the neck.

STUDY DESIGN

Retrospective review.

SETTING

Tertiary care center.

SUBJECTS AND METHODS

SPECT/CT images obtained preoperatively for patients undergoing SLN biopsy for cutaneous head and neck malignancy between June 2015 and June 2016 were reviewed by a blinded nuclear medicine physician and head and neck surgeon. SPECT/CT imaging was compared to intraoperatively determined SLN location via gamma probe. Sensitivity, specificity, and positive and negative predictive values were determined and compared for superficial (external jugular [EJ] and parotid) nodes vs level II nodes.

RESULTS

Fifty-three patients were included in the study. Most had cutaneous melanoma (69.8%). The PPV of EJ/parotid node identification by SPECT/CT imaging was 85.7%, specificity was 88.9%, and sensitivity was 69.2%. Comparatively, the PPV for level II nodes was 76.9%, specificity was 50%, and sensitivity was 85.7%. No significant difference in SPECT/CT predictive value was identified between EJ/parotid and level II node identification ( P > .05).

CONCLUSION

SPECT/CT imaging has strong specificity and positive predictability for preoperative localization of SLN superficial to the sternocleidomastoid muscle in cutaneous head and neck malignancy. SPECT/CT imaging may be a useful radiographic aid for preoperative SLN mapping in this patient population.

SPECT/CT Adds Distinct Lymph Node Basins and Influences Radiologic Findings and Surgical Approach for Sentinel Lymph Node Biopsy in Head and Neck Melanoma

BACKGROUND

Planar lymphoscintigraphy (PL) has a lower detection rate of sentinel lymph nodes (SLNs) in head and neck melanoma compared with other sites. We assessed situations when single-photon emission computed tomography/computed tomography (SPECT/CT) identified nodes not seen by PL. We also evaluated the impact of SPECT/CT on surgical approach and oncologic outcomes.

METHODS

Patients who underwent SLN biopsy (SLNB) for head and neck melanoma with PL and SPECT/CT between November 2011 and December 2016 were included. Surgeons and radiologists completed a real-time survey inquiring about the utility of SPECT/CT. Patients were divided into two groups: patients with nodal basins identified by both PL and SPECT/CT ('PL + SPECT/CT'), and patients in whom SPECT/CT identified additional nodal basins not seen on PL ('SPECT/CT only'). Patient demographics and long-term outcomes including follow-up duration, recurrence, and survival are described.

RESULTS

In the PL + SPECT/CT group, 73 (61.9%) patients were included and 45 (38.1%) patients were included in the SPECT/CT-only group. SPECT/CT added 51 basins to those seen on PL, primarily in the supraclavicular region (43.1%). Eighteen patients had positive node(s) in the PL + SPECT/CT group compared with two patients in the SPECT/CT-only group. Surgeons reported that 81% of the time, SPECT/CT influenced the location of incision for SLNB.

CONCLUSIONS

SPECT/CT influences the location of incision and contributes most to identification of nodes in the supraclavicular region. It also detects additional SLN basins when compared with PL. Further studies are necessary to determine when these additional basins require sampling.

Multi-slice SPECT/CT vs. lymphoscintigraphy and intraoperative gamma ray probe for sentinel node mapping in HNSCC

To assess the diagnostic potential of multi-slice single-photon emission computed tomography/computed tomography (SPECT/CT) for preoperative sentinel node (SN) mapping in early stage head and neck squamous cell carcinoma (HNSCC). Retrospective case-control study including data of consecutive HNSCC patients treated between November 2011 and December 2015. The diagnostic accuracy of multi-slice SPECT/CT was assessed with regard to the gold standard intraoperative gamma ray detection probe, using McNemar's test and calculating the area under the ROC curve. Additionally, the hot spot yield of SPECT/CT and planar lymphoscintigraphy (LS) was compared. Compared to the intraoperative gold standard, SPECT/CT showed an overall positive predictive value of 60.3% [confidence interval (CI) 46.6-73.0%)], a negative predictive value of 96.3% (CI 93.6-98.1%), and an accuracy of 90.8% (CI 89.1-92.4%). SPECT/CT detected more hot spots than LS and provided detailed anatomical information as well as relevant additional findings with potential impact on further patient management. Sentinel lymph node biopsy proved to be a reliable and safe procedure with an excellent SN excision rate (97%). Multi-slice SPECT/CT is a highly accurate diagnostic test and matches the gold standard intraoperative gamma ray detection probe.

Contemporary use of sentinel lymph node biopsy in the head and neck

Sentinel lymph node biopsy has become a well-established and commonplace practice in many oncologic disease sites as a means to stage the regional lymphatics, avoid unnecessary surgery and decrease patient morbidity. In the head and neck, its role is well established for cutaneous melanoma with proven fidelity and survival benefit. Its role in use for other sites such as oral cavity carcinoma continues to develop with promising results from several recent trials. Although not widely adopted, the potential benefits of sentinel lymph node biopsy in the management of oral cavity carcinoma are apparent. Refinements in technology and protocols including development of novel radiopharmaceutical tracers, routine incorporation of detailed anatomic imaging, increasing surgeon experience and development of new intraoperative identification aids will likely lead to improvements in the use and accuracy of this technique.

Clinical Usefulness of a Novel Freehand 3D Imaging Device for Radio-Guided Intraoperative Sentinel Lymph Node Detection in Malignant Melanoma

INTRODUCTION

Patients with invasive malignant melanoma are commonly referred for sentinel lymph node (SLN) detection. A recently proposed 3D tomographic imaging modality is freehand SPECT (declipseSPECT). This "bedside system" was originally developed to enable minimal-invasive image-guided surgery. The aim of this retrospective analysis was to assess the clinical use of this freehand detector device for image-guided lymphatic mapping in melanoma patients.

MATERIALS AND METHODS

Thirty-nine patients (12 female and 27 male subjects) were included (age, 30-79 years). All of them had at least one location of melanoma with tumoral stage pT1b or greater in 37 and pTx in 2 patients in different sites of the body (abdomen in 4, back in 14, head and neck in 5, lower extremity in 6, and upper extremity in 10 patients). Lymphoscintigraphy was performed with 65 to 127 MBq Tc-nanocolloid. A 2-day protocol was applied with SPECT-CT acquisition (Brightview XCT, Philips) at day 1 and surgery using radio-guided freehand SPECT at day 2. SPECT-CT data were integrated into the 3D navigation system to enable fast and direct localization of the SLN by displaying the depth of the node from the skin surface and lateral margins in relation to the gamma probe.

RESULTS

Comparable preoperative imaging and intraoperative localization was observed in 18 patients. In 14 cases, more lymph nodes were resected than detected by SPECT-CT including 1 patient without evidence of an SLN because this node was located close to the primary right ear tumor. In 10 of these patients, intraoperative freehand SPECT revealed additional sites of lymph nodes. In 7 cases, more findings were detected by SPECT-CT than surgically removed. The procedure was safe and easy to perform, and the time of surgical intervention using freehand SPECT was in the range of 36 to 133 minutes (mean time, 66.56 minutes).

CONCLUSIONS

Freehand SPECT detected more SLN compared with SPECT-CT, and the tracking system provided precise anatomical localization of the radioactive-labeled SLNs.