From Bench to Bedside in Tongue Muscle Cancer Invasion and Back again: Gross Anatomy, Microanatomy, Surgical Treatments and Basic Research

Subtotal glossectomy with conservation of the hyo-styloglossus unit (HSU): a new pivotal concept for preserving tongue function in extended glossectomy

Objective

The local spread of oral tongue squamous cell carcinoma (OTSCC) follows pathways of dissemination along areas of lesser resistance. In more advanced scenarios, the tumor can extend beyond the hemi-tongue of origin, by passing through the lingual septum and following the fibers of the transverse muscle. This can lead to the invasion of the contralateral extrinsic muscles, the first being the genioglossus and more laterally the hyoglossus. An anatomically guided surgical resection of the tumor can be planned to ensure both oncological safety and an acceptable functional outcome. This approach aims to preserve the hyo-styloglossus unit (HSU) whenever feasible.

Methods

Between January 2019 and November 2022, six patients received extended glossectomy Type B (EG Type B), with preservation of the HSU. Preliminary oncological results and functional results in terms of swallowing (FOIS score) and quality of life (MDADI) are presented.

Results

Five out of the six patients are alive and disease-free, while one patient died due to other causes. All patients who were candidates for an EG Type B underwent a swallowing assessment prior to surgery and followed daily postoperative swallowing training. At discharge, the patients continued swallowing training in an outpatient clinic. Five out of the six patients reached a full oral diet within 1 year of follow-up.

Conclusion

The oncological results confirm the safety of this technique. The importance of preserving the HSU, the minimal functional unit, shows very encouraging results in terms of swallowing rehabilitation.

Prognostic impact of muscle invasion in buccal mucosa squamous cell carcinoma

OBJECTIVE

The objective of the study was to assess the prognostic value of muscle invasion (MI), a key histopathological feature of tumor aggressiveness, and construct a superior prognostic prediction model combining the current TNM staging system.

MATERIALS AND METHODS

MI was analyzed in the whole-slide images from a total of 301 patients with primary buccal mucosa squamous cell carcinoma (BMSCC). Survival times of patients with/without MI were evaluated by Kaplan-Meier analysis. MI was further combined with the TNM staging system to explore its predictive value for prognosis. Moreover, 204 cases of head and neck carcinoma from the TCGA database were included.

RESULTS

MI positive rate reached to 76% (229/301) in patients with BMSCC. MI was associated with poor overall survival (p = 0.012) and disease-free survival (p = 0.022). The novel system (TNM staging combined with MI) revealed strong predictive performance, with the largest area under the curve (OS: p < 0.001, DFS: p < 0.004). MI and the established classification system were also had good predictive ability in the TCGA cohort.

CONCLUSIONS

MI is an independent predictor of poor prognosis of BMSCC. The inclusion of MI in prediction system can augment the risk stratification of patients with oral squamous cell carcinoma and may assist in the clinical decision-making process.

f25, a novel synthetic quinoline derivative, inhibits tongue cancer cell invasion and survival by the PPAR pathway in vitro and vivo

Tongue cancer has a very high incidence in China, and there is a need to develop new anti-tumour drugs against it. We synthesised 31 novel quinoline derivatives to test their anti-tumour activity. A compound referred to as "f25" was identified through screening for its high in vitro toxicity against an oral squamous carcinoma cell line (CAL-27). f25 exhibited significant cytotoxicity against CAL-27 cells (IC50 = 7.70 ± 0.58 μΜ). f25 also inhibited the migration and invasion of CAL-27 cells to a level comparable with that of the chemotherapy agent cisplatin. Moreover, f25 promoted the apoptosis of CAL-27 cells. Transcriptome sequencing and western blotting showed that the mechanism of action of f25 against CAL-27 cells involved the peroxisome proliferator-activated receptor (PPAR) signalling pathway. Specifically, f25 could bind to PPAR-α, PPAR-β, and PPAR-γ and increase their expression. In vivo experiments showed that treatment with f25 led to a reduction in tumour volume in nude mice without significant toxicity. Overall, this study highlights the potential of quinoline compounds (particularly f25) for the design and synthesis of anti-tumour drugs. It also underscores the importance of the PPAR signalling pathway as a target for potential cancer therapies.

Image-Guided Intraoperative Assessment of Surgical Margins in Oral Cavity Squamous Cell Cancer: A Diagnostic Test Accuracy Review

(1) Background: The assessment of resection margins during surgery of oral cavity squamous cell cancer (OCSCC) dramatically impacts the prognosis of the patient as well as the need for adjuvant treatment in the future. Currently there is an unmet need to improve OCSCC surgical margins which appear to be involved in around 45% cases. Intraoperative imaging techniques, magnetic resonance imaging (MRI) and intraoral ultrasound (ioUS), have emerged as promising tools in guiding surgical resection, although the number of studies available on this subject is still low. The aim of this diagnostic test accuracy (DTA) review is to investigate the accuracy of intraoperative imaging in the assessment of OCSCC margins. (2) Methods: By using the Cochrane-supported platform Review Manager version 5.4, a systematic search was performed on the online databases MEDLINE-EMBASE-CENTRAL using the keywords "oral cavity cancer, squamous cell carcinoma, tongue cancer, surgical margins, magnetic resonance imaging, intraoperative, intra-oral ultrasound". (3) Results: Ten papers were identified for full-text analysis. The negative predictive value (cutoff < 5 mm) for ioUS ranged from 0.55 to 0.91, that of MRI ranged from 0.5 to 0.91; accuracy analysis performed on four selected studies showed a sensitivity ranging from 0.07 to 0.75 and specificity ranging from 0.81 to 1. Image guidance allowed for a mean improvement in free margin resection of 35%. (4) Conclusions: IoUS shows comparable accuracy to that of ex vivo MRI for the assessment of close and involved surgical margins, and should be preferred as the more affordable and reproducible technique. Both techniques showed higher diagnostic yield if applied to early OCSCC (T1-T2 stages), and when histology is favorable.

Beyond the boundaries of compartmental hemiglossectomy: a proposal for an anatomically based classification of surgical approaches to advanced oral tongue squamous cell carcinoma

INTRODUCTION

In the last decade, compartmental surgery (CTS) has been the surgical approach of choice for advanced tumors of the tongue and oral floor.

METHODS

Advanced tumors (cT3-T4) oral tongue squamous cell carcinoma (OTSCC) may extend beyond the lingual septum and involve the contralateral hemitongue, developing along the intrinsic transverse muscle. The disease may then involve the genioglossus muscle and, more laterally, the hyoglossus muscle.

RESULTS

The surgical approach to the contralateral tongue must be guided by anatomic and anatomopathological principles to achieve a safe oncological resection based on the principles of CTS.

CONCLUSION

We propose a schematic classification of glossectomies that extend to the contralateral hemitongue based on the anatomy and pathways of tumor spread.

The Role of Peritumoral Depapillation and Its Impact on Narrow-Band Imaging in Oral Tongue Squamous Cell Carcinoma

A recent study reported that the occurrence of depapillated mucosa surrounding oral tongue squamous cell carcinomas (OTSCC) is associated with perineural invasion (PNI). The present study evaluates the reliability of depapillation as a PNI predictor and how it could affect narrow-band imaging (NBI) performance. This is thus a retrospective study on patients affected by OTSCC submitted to radical surgery. The preoperative endoscopy was evaluated to identify the presence of depapillation. Differences in distribution between depapillation and clinicopathological variables were analyzed. NBI vascular patterns were reported, and the impact of depapillation on those was studied. We enrolled seventy-six patients. After evaluation of the preoperative endoscopies, 40 (53%) patients had peritumoral depapillation, while 59 (78%) had a positive NBI pattern. Depapillation was strongly correlated to PNI, 54% vs. 28% (p = 0.022). Regarding the NBI pattern, there was no particular association with depapillation-associated tumors. The presence of depapillation did not affect the intralesional pattern detected by the NBI, while no NBI-positive pattern was found in the depapillation area. Finally, the NBI-guided resection margins were not affected by depapillation. Peritumoral depapillation is a reliable feature for PNI in OTSCC. NBI margin detection is not impaired by depapillation.

Prognosis of tongue squamous cell carcinoma associated with individual surgical margin and pathological features

The specific muscular structure of the tongue greatly affects margin shrinkage and tumor invasion, making the optimal surgical margin controversial. This study investigated surgical margin correlated prognosis of TSCC (tongue squamous cell carcinoma) according to margin location and its value, and the histopathologic factors which are suggestive of tumor invasion. And we would like to propose defining of the surgical margin for TSCC via prognosis according to location and margin values. We reviewed 45 patients diagnosed with TSCC who visited Seoul National University Dental Hospital (SNUDH) (Seoul, Republic of Korea) from 2010 to 2019, who were managed by a single surgical team. Patient clinical and pathological data of patients were retrospectively reviewed, and in 36 out of 45 patients, the pathologic parameters including the worst pattern of invasion (WPOI) and tumor budding were investigated via diagnostic histopathology slide reading. When standardized with as 0.25 cm anterior margins, as 0.35 cm deep margin, there was no significant difference in disease specific survival (DSS) or loco-regional recurrence-free survival (LRFS). Additionally, there was a non-significant difference in DSS and LRFS at the nearest margin of 0.35 cm (PDSS=0.276, PLRFS=0.162). Aggressive WPOI and high tumor budding showed lower survival and recurrence-free survival, and there were significant differences in close margin and involved margin frequencies. In TSCC, the value and location of the surgical margin did not have a significant relationship with prognosis, but WPOI and tumor budding suggesting the pattern of muscle invasion affected survival and recurrence-free survival. WPOI and tumor budding should be considered when setting an optimal surgical margin.

The T-N tract involvement as a new prognostic factor for PORT in locally advanced oral cavity tumors

OBJECTIVE

The space comprised between tumor and neck lymph nodes (T-N tract) is one of the main routes of tumor spread in oral cavity tumors. Aim of the study was to investigate the impact of T-N tract involvement on the postoperative radiotherapy (PORT) outcomes.

MATERIALS AND METHODS

Patients (pts) treated between 2000 and 2016 with indication to PORT were retrospectively retrieved. Inclusion criteria were: (a) locally advanced tumors of the oral cavity, (b) who received with indication to PORT (c) with a minimum follow-up of six months.

RESULTS

One hundred and fifty-seven pts met the inclusion criteria (136 pts treated with PORT and 21 pts not treated with PORT). In the PORT cohort, the T-N tract involvement had no impact on both OS (p = .09) and LRFS (p = .2). Among the non-PORT cohort, both OS (p = .007) and LRFS (p = .017) were worse for pts with positive T-N tract compared to those with negative T-N tract. PORT improved both OS (p = .008) and LRFS (p = .003) in pts with positive T-N tract but not in those with negative T-N tract (p = .36 and p = .37, respectively).

CONCLUSIONS

Our results suggest that involvement of T-N tract should be considered as prognostic factors informing the indication to PORT.