Defining optimum surgical margins in buccoalveolar squamous cell carcinoma

Impact of Close Margins on Oral Cancer Outcomes According to the Oral Subsite

BACKGROUND

The prognostic significance of close margins in oral squamous cell carcinoma (OSCC) is controversial. We wished to investigate the impact of close margins on the risk of local recurrence (LR) in OSCC according to the oral subsite.

METHODS

A retrospective cohort study of 342 OSCC patients undergoing primary surgical treatment was conducted. Surgical margins were based on the main specimen and defined as positive (SCC at margins), close (< 5 mm), or clear (≥ 5 mm).

RESULTS

Among tongue SCC cases, both positive (hazard ratio 13.48, 95% CI 2.03, 32.91) and close margins (hazard ratio 3.87, 95% CI 1.31, 11.34) were significantly associated with LR. Tongue margins < 4 mm were associated with higher LR. Among non-tongue SCC cases, only positive margins (hazard ratio 4.10, 95% CI 1.19, 14.21) were associated with LR. Close margins were not significant (hazard ratio 1.59, 95% CI 0.46, 5.42).

CONCLUSIONS

Close margins appear to have a differential impact on LR in OSCC according to the oral subsite.

Oncologic significance of the lateral margin in buccal cancer

OBJECTIVE

To evaluate the specific oncologic significance of the lateral margin (LM)- the marginal plane closest to skin- in resected buccal cancer.

MATERIALS AND METHODS

216 consecutive, treatment naïve patients undergoing primary surgery for buccal cancer were included. Cheek skin was resected based on clinical features of skin or subcutaneous involvement or proximity to oral commissure. Main outcomes were 1) frequency of LM ≤1 mm in relation to other (anterior, posterior, superior and inferior) margins and 2) association of LM ≤1 mm with LRFS and DFS. Secondary outcomes were rate of LM ≤1 mm and size of LM with and without skin resection.

RESULTS

A total of 67 (31 %) patients had one or more margin ≤1 mm, of which LM comprised 36 (54 %). LM ≤1 mm was disproportionately highest among the five marginal planes (p < 0.001) and was independently associated with LRFS and DFS. Both associations held in sensitivity analysis wherein patients with co-existent margin ≤1 mm at any of the other four marginal planes underwent group-wise exclusion. Skin resection and preservation was performed in 61 (28 %) and 155 (72 %) patients respectively. The latter had a higher rate of LM ≤1 mm and smaller LM size (both p < 0.05).

CONCLUSIONS

This cohort study of buccal cancer shows that LM is most prone for ≤1 mm size. LM ≤1 mm predicts worse LRFS and DFS independent of other margins and risk factors. As skin preservation is associated with a higher rate of LM ≤1 mm, surgeons must lower the threshold to encompass more tissue laterally, including skin where appropriate.

Optimizing surgical margins in oral cancer without frozen section: A single center retrospective study

PURPOSE

Frozen section analysis has been a cornerstone in intraoperative pathological evaluation for oral cancer surgeries, aiding in achieving tumor-free margins. However, its utility and availability are subjects of ongoing debate and research. This study evaluates the efficacy of a guideline-based approach to surgical resection margins in the absence of frozen section analysis in a resource-constrained setting.

MATERIALS AND METHODS

We conducted a retrospective audit of 490 oral cavity cancer patients treated from December 2021 to December 2023 at our center, where frozen section analysis was not available. Surgical resections adhered to the guidelines of maintaining 1 cm mucosal soft tissue and base margins, and a 7 mm specimen-driven margin assessment intraoperatively. The outcomes measured were the rates of close (between 1 mm and 5 mm) and involved (less than or equal to 1 mm) margins in final histopathology reports (HPR).

RESULTS

448 patients were included in our audit. On final HPR, a gross margin of 7 mm or more achieved intraoperatively translated into safe (more than 5 mm) margins in 410 patients (91.1 %). 25 (5.1 %) had at least one close margin, of which 11 were technical due to the desire to minimize functional morbidity. 15 (3.1 %) had involved margins, where R0 resection was not achieved due to anatomical constraints. An additional finding was the correlation of compromised margins with worst pattern of invasion (WPOI) 4&5 on Chi-square analysis (p = 0.021) and depth of invasion (DOI) more than 5 mm (OR 3.81, p = 0.010).

CONCLUSION

This study indicates that a margin of 7 mm or more intraoperatively translates into safe margins on final HPR, and calls for a pragmatic and judicious use of FS in the interest of choosing wisely.

Margin status, adjuvant treatment and recurrence in buccal cancer

OBJECTIVE

To assess the prognostic importance of margin in resected buccal cancer within a framework of risk factor-driven postoperative adjuvant treatment.

MATERIALS AND METHODS

Consecutive, treatment naïve patients undergoing primary surgical treatment for buccal cancer. Margin was defined as clear (≥5 mm), close (1-4 mm) and involved (<1 mm). Main outcome was association of margin with local recurrence free survival (LRFS). Subgroup analysis of close margin was performed according to receipt or no receipt of adjuvant treatment. A numerical margin cut-off in mm that could independently predict LRFS was sought to be identified.

RESULTS

Of the 167 patients included, the frequency of clear, close and involved margins was 50 (30 %), 78 (47 %) and 39 (23 %) respectively, among whom 52 %, 44 % and 98 % received postoperative adjuvant treatment respectively. Clear and close margins had similar 3-year LRFS (89 % and 96 % respectively), while involved margin had worse 3-year LRFS at 65 %. Involved margin was confirmed to be strongly and independently associated with worse LRFS. Within close margin, receipt and no receipt of adjuvant treatment had similar 3-year LRFS (92 % and 100 % respectively). A margin cut-off of 2 mm was identified at or above which LRFS approximated that of clear margin.

CONCLUSIONS

This single center cohort study of patients with resected buccal cancer suggests that close margin is distinct from and has a better LRFS than involved margin. A subset of close margin, with margin size ≥ 2 mm and no other adverse features, might be spared adjuvant treatment without compromising outcomes.

Surgical margins in head and neck squamous cell carcinoma: A narrative review

Head and neck squamous cell carcinoma (HNSCC), a prevalent and frequently recurring malignancy, often necessitates surgical intervention. The surgical margin (SM) plays a pivotal role in determining the postoperative treatment strategy and prognostic evaluation of HNSCC. Nonetheless, the process of clinical appraisal and assessment of the SMs remains a complex and indeterminate endeavor, thereby leading to potential difficulties for surgeons in defining the extent of resection. In this regard, we undertake a comprehensive review of the suggested surgical distance in varying circumstances, diverse methods of margin evaluation, and the delicate balance that must be maintained between tissue resection and preservation in head and neck surgical procedures. This review is intended to provide surgeons with pragmatic guidance in selecting the most suitable resection techniques, and in improving patients' quality of life by achieving optimal functional and aesthetic restoration.

Should sub-millimeter margins be deemed positive in oral cavity squamous cell carcinoma?

BACKGROUND

While several studies have indicated that a margin status of < 1 mm should be classified as a positive margin in oral cavity squamous cell carcinoma (OCSCC), there is a lack of extensive cohort studies comparing the clinical outcomes between patients with positive margins and margins < 1 mm.

METHODS

Between 2011 and 2020, we identified 18,416 Taiwanese OCSCC patients who underwent tumor resection and neck dissection. Of these, 311 had margins < 1 mm and 1013 had positive margins. To compare patients with margins < 1 mm and those with positive margins, a propensity score (PS)-matched analysis (n = 253 in each group) was conducted.

RESULTS

The group with margins < 1 mm displayed a notably higher prevalence of several variables: 1) tongue subsite, 2) younger age, 3) smaller depth of invasion), 4) early tumor stage, and 5) treatment with surgery alone. Patients with margins < 1 mm demonstrated significantly better disease-specific survival (DSS) and overall survival (OS) rates compared to those with positive margins (74 % versus 53 %, 65 % versus 43 %, both p < 0.0001). Multivariable analysis further confirmed that positive margins were an independent predictor of worse 5-year DSS (hazard ratio [HR] = 1.38, p = 0.0103) and OS (HR = 1.28, p = 0.0222). In the PS-matched cohort, the 5-year outcomes for patients with margins < 1 mm compared to positive margins were as follows: DSS, 71 % versus 59 %, respectively (p = 0.0127) and OS, 60 % versus 48 %, respectively (p = 0.0398).

CONCLUSIONS

OCSCC patients with a margin status < 1 mm exhibited distinct clinicopathological characteristics and a more favorable prognosis compared to those with positive resection margins.

Stratification of surgical margin distances by the millimeter on local recurrence in oral cavity cancer: A systematic review and meta-analysis

There are limited data supporting the commonly suggested 5 mm margin cutoff as the optimum value in defining clear margins in oral cancer. A database search of Pubmed/Medline, Web of Science, and EBSCOhost was performed from inception to June 2022. A random-effects model was chosen for this meta-analysis. The Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines were followed throughout this study. Seven studies met study criteria (2215 patients). The risk ratio was significantly higher for margins <5 mm when compared to those ≥5 mm (2.09 (95%CI: 1.53-2.86, I2  = 0.47)). Subgroup analysis (I2  = 0.15) of margin distances of 0.0-0.9, 1.0-1.9, 2.0-2.9, 3.0-3.9, and 4.0-4.9 mm calculated risk ratios for local recurrence of 2.96, 2.01, 2.17, 1.8, and 0.98, respectively. Margins between 4.0 and 4.9 mm had similar risk ratios for local recurrence compared to ≥5 mm, while margins <4.0 were significantly higher.

Impact of Close Margins in Head and Neck Mucosal Squamous Cell Carcinoma: A Systematic Review

OBJECTIVES/HYPOTHESIS

The aim of the study is to investigate whether close surgical margins impact oncologic outcomes compared to clear or involved surgical margins. We hypothesize that close surgical margins portend worse outcomes compared with clear margins, but improved outcomes compared with involved margins.

STUDY DESIGN

Systematic review.

METHODS

Using the Preferred Reporting Items for Systematic Reviews and Meta-analysis statement standards, a systematic search was conducted for studies that reported oncologic outcomes following excision of primary mucosal head and neck squamous cell carcinoma (HNSCC). A meta-analysis was then performed, comparing local recurrence (LR), locoregional recurrence (LRR), and overall survival (OS) in patients with clear, close, and involved margins.

RESULTS

Twenty-six studies met the inclusion criteria, totaling 8,435 patients. About 96% of our included cases involved the oral cavity, 2% involved the oropharynx, and 2% other. Also, 68% of cases were T1/T2 and 32% were T3/T4. On meta-analysis, clear margins were associated with lower incidence of 5-year LR relative risk (RR) 0.50, 95% confidence interval [CI] 0.38-0.65) and higher 5-year OS (RR 1.22, 1.11-1.35), when compared with close margins. Involved margins had higher incidence of 5-year LR (RR 1.75, 1.16-2.64), higher incidence of LRR at last follow-up (RR 1.66, 1.37-2.00), and no difference in 5-year OS (RR 0.82, 0.60-1.11), when compared with close margins.

CONCLUSIONS

There is a stepwise improvement in oncologic outcomes as surgical margin categorically improves from involved to close to clear. Patients with close margins therefore may benefit from adjuvant therapy. Further research is required to investigate whether these findings are seen in non-oral cavity cases because they were underrepresented in this analysis. Laryngoscope, 2021.

The impact of intraoperative frozen section analysis on final resection margin status, recurrence, and patient outcome with oral squamous cell carcinoma

Background

The objective of this study was to evaluate the diagnostic value of intraoperative frozen section analysis (IFSA) of tumor bed margins in patients with oral squamous cell carcinoma (OSCC).

Methods

This retrospective study includes 194 primary OSCC cases. The impact of intraoperative information by IFSA on final margin status, local recurrence, and disease-specific survival were analyzed.

Results

IFSA revealed a 50% sensitivity and a 100% specificity, with a positive and negative predictive value of 100% and 89.1%, respectively. In 19 cases, margins were rated positive by IFSA and remained positive in eight cases (42.1%), despite immediate re-resection. This constellation led to higher recurrence and lower survival rates than in cases with consecutive R0 status (each p = 0.046). Positive margins in IFSA were associated with closer final margins (p = 0.022) and early recurrences (p = 0.050).

Conclusions

Achieving instant R0 status has a crucial impact on disease recurrence and patient survival. IFSA falls short to ensure secure definite surgical margins. Thus, improved intraoperative diagnostic information on the location and extent of OSCC could support patient treatment.

Clinical relevance

Considering that patient survival has not improved despite progress in surgical and adjuvant therapy, the process and outcome of IFSA was scrutinized as one part of the treatment concept.

Intraoperative Margin Assessment in Oral and Oropharyngeal Cancer Using Label-Free Fluorescence Lifetime Imaging and Machine Learning

OBJECTIVE

To demonstrate the diagnostic ability of label-free, point-scanning, fiber-based Fluorescence Lifetime Imaging (FLIm) as a means of intraoperative guidance during oral and oropharyngeal cancer removal surgery.

METHODS

FLIm point-measurements acquired from 53 patients (n = 67893 pre-resection in vivo, n = 89695 post-resection ex vivo) undergoing oral or oropharyngeal cancer removal surgery were used for analysis. Discrimination of healthy tissue and cancer was investigated using various FLIm-derived parameter sets and classifiers (Support Vector Machine, Random Forests, CNN). Classifier output for the acquired set of point-measurements was visualized through an interpolation-based approach to generate a probabilistic heatmap of cancer within the surgical field. Classifier output for dysplasia at the resection margins was also investigated.

RESULTS

Statistically significant change (P 0.01) between healthy and cancer was observed in vivo for the acquired FLIm signal parameters (e.g., average lifetime) linked with metabolic activity. Superior classification was achieved at the tissue region level using the Random Forests method (ROC-AUC: 0.88). Classifier output for dysplasia (% probability of cancer) was observed to lie between that of cancer and healthy tissue, highlighting FLIm's ability to distinguish various conditions.

CONCLUSION

The developed approach demonstrates the potential of FLIm for fast, reliable intraoperative margin assessment without the need for contrast agents.

SIGNIFICANCE

Fiber-based FLIm has the potential to be used as a diagnostic tool during cancer resection surgery, including Transoral Robotic Surgery (TORS), helping ensure complete resections and improve the survival rate of oral and oropharyngeal cancer patients.

Optimum surgical margins in squamous cell carcinoma of the oral tongue: Is the current definition adequate?

OBJECTIVES

To evaluate the impact of progressively increasing margin distances on locoregional recurrence-free survival (LFRS) and determine an optimum margin distance for tongue cancers.

METHODS

We retrospectively reviewed the records of patients with squamous carcinoma of oral tongue, surgically treated between January 2012 and December 2013. The patients were divided based on ROC derived optimal distance and differences in LRFS per millimeter: margin distances with no significant difference in LRFS starting from 0 mm onwards (Group-I), from upper limit of Group-I to ROC cut-off (Group-II), and all values above it (Group-III). Group-II and III were matched for clinicopathologic factors and type of adjuvant therapy received.

RESULTS

451 patients had a median LRFS of 29.4 months that included 32.1% of Stage I/II and 51.7% of Stage III/IV. Group-I consisted of 0--2.0 mm (2.0-2.1 mm (p-0.029)), Group-II form 2.1 to 7.5 (7.5-7.6 mm (p-0.042)) and Group-III were ≥ 7.6 mm. In the matched group, each millimeter increase in margin provided a 3.67 months survival advantage from 2.1 mm to 7.5 mm while a substantial advantage of 15 months was seen from 7.5 to 7.6 mm. No significant advantage was gained in LRFS when the margin was increased by a millimeter from the cut-off value (p-0.602). Among the patients that were not prescribed any adjuvant therapy, a significantly better LRFS was observed in Group III than Group II (HR-3.01, p-value = 0.002).

CONCLUSION

Based on these results, adequacy of surgical margins should be re-considered for oral tongue cancers.

Management of early oral cavity squamous cancers

Early oral cavity cancers comprise a favorable entity, amenable to clinical staging and single modality treatment. Surgery typically forms the mainstay of treatment and should ideally address both the primary and the neck in all cases. Careful attention must be paid to reconstruction and rehabilitation of such patients. Radical radiotherapy mainly in the form of brachytherapy can achieve excellent disease related and functional outcomes in a carefully chosen subset of patients. Increasingly, a subset of patients is being recognized, who harbor single or multiple adverse features on histopathology and may therefore benefit from escalation of adjuvant therapy. This review discusses the management of early oral cavity squamous carcinomas (Early OSCCs) in detail and highlights the dilemmas and controversies faced in the management of the same.