Detection of Occult Metastases in Patients with T1 and T2 Stage Lower Lip Squamous Cell Carcinomas after Positive Lymphoscintigraphy

Rate of occult metastasis in lip squamous cell carcinoma: A systematic review and meta-analysis

OBJECTIVES

The rate of occult metastasis in lip cancer is poorly studied. Management of the regional nodal basin in lip cancer is thus controversial. This study sought to understand the true rate of micrometastasis in lip cancer.

MATERIALS AND METHODS

Systematic review and meta-analysis was conducted of English language studies reporting lip cancer sentinel node biopsy results. Studies were obtained from the PubMed database between the years 2000 and 2023 using the search terms "sentinel node biopsy" and "squamous cell carcinoma." Random effect and fixed effect meta-analyses were performed.

RESULTS

Thirteen studies met inclusion criteria. Low heterogeneity was noted among the studies, as indicated by the I2 inconsistency test (I2 = 0%). The rate of occult metastasis ranged between 0 and 33% (mean 9%). A total of 189 lip sentinel node biopsies had been performed. Of these, 21 revealed occult nodal metastasis (11.1%, 95% CI 7.36%-16.44%). One step, generalized linear mixed modeling revealed the true rate of occult nodal metastasis to be 10% (95% CI (0.0504, 0.1746), p < 0.0001).

CONCLUSION

The rate of occult metastasis in lip cancer approaches the threshold for elective management of the regional nodal basin. Sentinel node biopsy is optimally suited for management of high-risk early T stage lip cancer.

Sentinel lymph node detection by combining nonradioactive techniques with contrast agents: State of the art and prospects

The status of sentinel lymph nodes (SLNs) has a substantial prognostic value because these nodes are the first place where cancer cells accumulate along their spreading route. Routine SLN biopsy ("gold standard") involves peritumoral injections of radiopharmaceuticals, such as technetium-99m, which has obvious disadvantages. This review examines the methods used as "gold standard" analogs to diagnose SLNs. Nonradioactive preoperative and intraoperative methods of SLN detection are analyzed. Promising photonic tools for SLNs detection are reviewed, including NIR-I/NIR-II fluorescence imaging, photoswitching dyes for SLN detection, in vivo photoacoustic detection, imaging and biopsy of SLNs. Also are discussed methods of SLN detection by magnetic resonance imaging, ultrasonic imaging systems including as combined with photoacoustic imaging, and methods based on the magnetometer-aided detection of superparamagnetic nanoparticles. The advantages and disadvantages of nonradioactive SLN-detection methods are shown. The review concludes with prospects for the use of conservative diagnostic methods in combination with photonic tools.