Lymphatic mapping with SPECT‐CT for evaluation of contralateral drainage in lateralized oropharyngeal cancers using an awake injection technique

A multi-institutional feasibility lead-in trial of lymphatic mapping with SPECT-CT for evaluating contralateral disease in lateralized oropharynx cancer using 99m-technetium sulfur colloid

BACKGROUND

Lymphatic mapping with SPECT-CT has been demonstrated to accurately define lymphatic drainage patterns in oropharyngeal cancer but there has yet to be a study demonstrating its feasibility across multiple institutions.

METHODS

Twelve adult patients with lateralized oropharyngeal carcinoma (T1-T3) who were planned for definitive or adjuvant radiotherapy without contralateral nodal disease underwent injection of 99-m technetium sulfur colloid followed by static planar lymphoscintigraphy to verify tracer migration, and SPECT-CT acquired at 30 ± 15 min (optional) and 3 h (±1 h) (mandatory time-point).

RESULTS

All 12 patients completed the study with 7/12 patients having the injections performed under local anesthetic and 5 patients requiring general anesthetic. There were no tracer migration failures and there were no serious adverse events or complications encountered. Four out of 12 patients (33%) showed contralateral drainage patterns.

CONCLUSIONS

Lymphatic mapping with SPECT-CT of lateralized oropharyngeal squamous cell carcinoma can be performed safely across multiple institutions.

Sentinel node identification in laryngeal and pharyngeal carcinoma after flexible endoscopy-guided tracer injection under topical anesthesia: A feasibility study

BACKGROUND

The aim of this study was to investigate the feasibility of flexible endoscopy-guided tracer injection for sentinel lymph node (SLN) identification in patients with laryngeal and pharyngeal carcinoma.

METHODS

Sixteen cT1-4N0-2M0 patients with laryngeal or pharyngeal carcinoma underwent intra- and peritumoral [^99m Tc]Tc-nanocolloid injections after topical anesthesia under endoscopic guidance. SPECT-CT scans were performed at two time points.

RESULTS

Tracer injection and visualization of SLNs was successful in 15/16 (94%) patients. Median number of tracer injections was 1 intratumoral and 3 peritumoral. The median duration of the endoscopic procedure including tracer injection after biopsy taking was 7 min (range 4-16 min). A total of 28 SLNs were identified which were all visualized on the early and late SPECT-CT. Most SLNs were visualized in neck levels II and III.

CONCLUSIONS

Flexible endoscopy-guided tracer injection for SLN identification is a feasible and fast procedure in laryngeal and pharyngeal carcinoma patients.

Evaluating contralateral neck failure in patients with lateralized OPSCC treated with transoral robotic surgery and neck management based on pre-operative SPECT-CT lymphatic mapping

BACKGROUND

Risk of contralateral nodal metastases in oropharyngeal squamous cell carcinoma (OPSCC) is relatively low, however, many OPSCC patients receive bilateral neck treatment. This study evaluates the oncological outcomes with management of the contralateral cN0 neck based on lymphatic mapping with single photon emission computed tomography (SPECT-CT).

METHODS

Retrospective evaluation of patients with lateralized cT1-2 and contralateral cN0 OPSCC treated with primary surgery between December 2017 and October 2019. All patients underwent pre-operative lymphatic mapping using SPECT-CT. Clinical parameters including demographics, tumor characteristics and oncological outcomes were recorded.

RESULTS

Thirteen patients underwent primary site resection with transoral robotic surgery (TORS) and ipsilateral neck dissection with or without adjuvant therapy. Twelve patients (92.3%) had ipsilateral drainage on SPECT-CT, whereas 1 (7.7%) patient had bilateral neck lymphatic drainage. Four patients (30.8%) underwent post-operative radiation therapy (PORT). Three patients with unilateral drainage on SPECT-CT underwent PORT with unilateral neck irradiation, and 1 patient with bilateral drainage underwent PORT with bilateral neck irradiation. Seven (53.8%) patients were staged as pT1, 6 (46.2%) patients as pT2, 6 (46.2%) patients were pN0, 3 (23.1%) patients were pN1, 1 (7.7%) patient was pN2a for and 3 (23.1%) patients were N2b. The median distance of the tumor from midline was 1.05 cm (0.0-1.58). Primary sites included tonsil (n = 10, 76.9%) and tongue base (n = 3, 23.1%). The median follow-up time was 15.4 months. All patients were disease free at the latest follow-up with no contralateral neck failures.

CONCLUSIONS

Pre-operative mapping of lymphatic drainage in early stage OPSCC with SPECT-CT is a promising tool which can reduce treatment to the contralateral neck potentially without compromising oncological outcomes.

Comparing unilateral vs. bilateral neck management in lateralized oropharyngeal cancer between surgical and radiation oncologists: An international practice pattern survey

BACKGROUND

Management of the neck in oropharyngeal carcinoma varies due to a lack of clarity of patterns of lymphatic drainage and concern of failure in the contralateral neck. With recent advances in transoral surgical techniques, surgical management has become increasingly prevalent as the primary treatment modality. We compare international practice patterns between surgical and radiation oncologists.

METHODS

A survey of neck management practice patterns was developed and pilot tested by 6 experts. The survey comprised items eliciting the nature of clinical practice, as well as patterns of neck management depending on extent of nodal disease and location and extent of primary site disease. Proportions of surgical and radiation oncologists treating the neck bilaterally were compared using the chi-squared statistic.

RESULTS

Two-hundred and twenty-two responses were received from 172 surgical oncologists, 44 radiation oncologists, 3 medical oncologists, and 3 non-oncologists from 32 different countries. For tongue base cancers within 1 cm of midline (67% vs. 100%, p < 0.001), and for tonsil cancers with extension to the medial 1/3 of the soft palate (65% vs. 100%, p < 0.001) or tongue base (77% vs. 100%, p < 0.001), surgical oncologists were less likely to treat the neck bilaterally. For isolated tonsil fossa cancers with no nodal disease, both surgical and radiation oncologists were similarly likely to treat unilaterally (99% vs. 97%, p = NS). However, with increasing nodal burden, radiation oncologists were more likely to treat bilaterally for scenarios with a single node < 3 cm (15% vs. 2%, p < 0.001), a single node with extranodal extension (41% vs. 18%, p < 0.001), multiple positive nodes (55% vs. 23% p < 0.001), and node(s) > 6 cm (86% vs. 33%, p < 0.001). For tumors with midline extension, even with a negative PET in the contralateral neck, the majority of surgical and radiation oncologists would still treat the neck bilaterally (53% and 84% respectively).

CONCLUSIONS

The present study demonstrates significant practice pattern variability for management of the neck in patients with lateralized oropharyngeal carcinoma. Surgical oncologists are less likely to treat the neck bilaterally, regardless of tumor location or nodal burden. Even in the absence of disease in the contralateral neck on imaging, them majority of practitioners are likely to treat bilaterally when the disease approaches midline.

Lymphoscintigraphy for Sentinel Node Mapping in Head and Neck Cancer

The aim of this comprehensive review is to describe and analyze the role of the sentinel node mapping in head and neck cancers. For this purpose, head and neck neoplasms have been categorized in cutaneous malignancies and neoplasms of the upper aerodigestive tract. A concise description of lymphatic drainage will be the "prelude" for each section, as well as the description of the injection techniques, when specific. Concisely, the attention has been focused on detection rate of the sentinel node by lymphoscintigraphy for each cancer, and for those patients in which the sentinel lymph node has been identified, true-positives rates, false-negative rates, and overall accuracy has been pointed out. Overall, in cutaneous neoplasms of the head and neck, the detection rate is higher than 90%, however the false-negative rate is still an issue, in particular in melanoma, inducing the need for newer developments. In fact, new tracers and techniques are already available, while prospective multicenter trials exploring the outcome impact are needed in the near future. For the upper aerodigestive tract and in particular oral cavity and oropharynx, sentinel lymph node identification by lymphoscintigraphy allows avoiding unnecessary neck dissection and/or node irradiation. Even in this case, the main limit remains the risk of false-negative rates. While, for patients affected by laryngeal and hypopharyngeal cancers the data seem very limited and, although the feasibility has been demonstrated, performances of this lymphoscintigraphy still need to be confirmed by multicenter studies.