Perineural Invasion in Squamous Cell Carcinoma of the Oral Cavity: Histology, Tumor Stage, and Outcome

Abstract

Objectives/Hypothesis: To analyze the impact of different types of perineural invasion (PNI) in squamous cell carcinoma (SCC) of the oral cavity on overall survival and recurrence rate, with a special focus on histologic subtypes and tumor stage.Study Design: Retrospective case-control study with clinicopathological analysis. Methods: Seventeen patients who received primary surgical treatment for SCC of the oral cavity with PNI were matched to a control group. In a histologic review, PNI was classified into subtypes according to an adapted Liebig classification. The term type A was used to describe tumor invasion into the nerve, whereas type B was used to describe circumferential growth around the nerve. Clinical charts were reviewed, and a Kaplan-Meier survival analysis was performed.Results: The recurrence-free survival rates were 47.1% versus 80.4% (PNI vs. matched control group, P < 0.05), 60.0% versus 94.1% (PNI in stage I and II disease vs. matched control group, P < 0.05) and 41.7% versus 73.5% (PNI in stage III and IV disease vs. matched control group, P < 0.05). In most cases (n 5 9) of PNI, both histologic subtypes (type A and type B) were present. Five cases exclusively showed type A, and three cases exclusively showed type B.Conclusions: Perineural invasion in early disease oral carcinoma has a particularly high impact on survival. Both histologic subtypes showed a significantly worse recurrence-free survival rate when compared to the control group.

Perineural Invasion and Perineural Tumor Spread in Head and Neck Cancer

“…7,13,22,26 PNI is considered an exacerbating feature that can worsen the prognosis of patients with surgical close margins, 21,27 and it has been associated with an increased risk of regional recurrence. 18,[28][29][30][31] Conversely, PNTS is not associated with greater risk of regional metastasis, but the locally mediated morbidity can be severe. In cases of advanced uncontrolled PNTS, patients experience debilitating symptoms such as neuropathic pain, numbness or other sensory nerve dysfunction, paralysis, disfigurement, and injury from motor nerve dysfunction.…”

“…Lastly, PNI is a relatively frequent finding in oral cavity SCC, and it correlates with poor clinical outcomes, especially if there is progression to PNTS. 29 The targeting of relevant CN pathways for such cases is based on previously published contouring guidelines, [58][59][60][61][62][63] the authors' collective experience, prediction of likely failure patterns, 60,[64][65][66] and anatomic localization of neural interconnections ( Table 3).…”

“…PNI more frequently develops in small, unnamed nerve fibers within the tumor specimen, at rates as high as 42% to 52%. 13,92 The presence of PNI in oral cavity cancer has been associated with worsened survival and regional nodal metastasis, [29][30][31] and the presence of PNI may be a factor warranting a neck dissection. PNI has also been demonstrated to be predictive of distant recurrences, 93 supporting its role as an adverse prognostic feature.…”

Assessment of morphological parameters associated with neural invasion in oral squamous cell carcinoma

“…According to the results of the study, a significant correlation was observed with NI and Habit, positive surgical margins and lymphovascular invasion. Several studies[ 15 16 ] have reported a positive association of NI with lymph node metastasis, depth of invasion and tumor differentiation. In our study too, increased incidence of NI was observed with deep invasion (80%), poorly differentiated tumors (57.14%) as well as with positive lymph nodes (31.4%); however, this did not reach statistical significance.…”

Mandibular Canal Widening and Bell’s Palsy: Sequelae of Perineural Invasion in Oral Cancer

“…Histopathology sections revealed pleomorphic tumour cells with individual cell keratinization and dense peritumoural inflammatory response. Representative histological section demonstrating PNI (Modified Liebig Type A Classification) and infiltration of the epineurium was also seen [9, 10] (Figures 1(f) and 1(g))…”