Management of mandibular invasion: When is a marginal mandibulectomy appropriate?

Evaluation of outcomes after conservative mandibular surgery in patients with oral squamous cell carcinoma

This study aimed to assess preoperative radiological and clinical examinations for identifying bone status and to evaluate survival outcomes in patients undergoing marginal mandibulectomy for the primary treatment of oral squamous cell carcinoma. The medical records, enhanced computed tomography (CT) scans, and pathological specimens of these patients were reviewed. Disease-free (DFS), local recurrence-free (LRFS), and osteoradionecrosis-free (ORNFS) survival were analysed. The study included 104 patients. The preoperative CT and clinical examinations achieved a sensitivity of 45.8% and specificity of 100% for judging bone condition. LRFS was 79.6% and DFS was 68.8%. Pathological bone invasion in significantly affected DFS (P = 0.597), while DFS was significantly higher for those with a lower clinical tumour stage (1/2 vs 3/4; P = 0.005) and postoperative radiotherapy (P = 0.011). Among 39 patients receiving postoperative radiotherapy, ORNFS was 75.2%. Postoperative chemotherapy significantly decreased ORNFS (P = 0.009). Tumour subsite (P = 0.003) and the resection site (P = 0.035) significantly affected the remaining bone height. The results indicate that CT and clinical examinations cannot precisely identify superficial bone damage, but work well in selecting patients for marginal resection. Adhering to current indications, this resection approach can guarantee safe bone margins in terms of survival outcomes.

Comparison of different diagnostic imaging techniques for the detection of bone invasion in oral cancers

OBJECTIVES

To evaluate the ability of different imaging modalities to accurately detect bone invasion in oral squamous cell carcinomas.

PATIENTS AND METHODS

Patients with oral squamous cell carcinoma, who were scheduled for mandibulectomy or maxillectomy, underwent clinical evaluation using five preoperative imaging diagnosis methods-contrast-enhanced MRI, CT, ^99mTc scintigraphy (Tc scan), FDG-PET CT (PET/CT), and panoramic radiography. The sensitivity and specificity of each modality in detecting bone invasion were calculated by comparing the findings on the images with postoperative histopathological findings. In a subgroup of patients, we further assessed the ability of MRI and CT to detect the accurate extent of bone invasion, including the height, width, and depth in patients with pathological mandibular invasion.

RESULTS

Overall, 50 patients were enrolled in this study, and nine patients with pathological mandibular invasion were included in our subgroup analysis. MRI was found to be the most useful method in detecting bone invasion, showing the highest sensitivity (88.9%) and negative predictive values (92.3%). CT (87.5% specificity and 77.8% sensitivity) was more specific than MRI, though less sensitive. Combined PET/CT was more sensitive (83.3%) and less specific (71.9%) than CT. Tc scan had high sensitivity (88.9%); however, the specificity was relatively low (71.9%).

CONCLUSION

MRI was the most useful method in detecting bone invasion. A negative MRI result definitively excludes bone marrow invasion. In patients with positive MRI findings, a negative CT may be useful in ruling out bone marrow invasion.

Postoperative radiotherapy is associated with improved overall survival for alveolar ridge squamous cell carcinoma with adverse pathologic features

BACKGROUND

Alveolar ridge squamous cell carcinoma (ARSCC) is poorly represented in randomized trials.

METHODS

Adults in the National Cancer Database diagnosed with ARSCC between 2010 and 2014 who should be considered for postoperative radiotherapy (PORT) based on National Comprehensive Cancer Network (NCCN)-defined risk factors were identified.

RESULTS

Eight hundred forty-five (58%) of 1457 patients meeting the inclusion criteria received PORT. PORT was associated with improved overall survival (OS) on unadjusted (hazard ratio [HR] 0.83, 95% confidence interval [CI] 0.70-0.98, P = .02) and multivariable (HR 0.78, 95% CI 0.64-0.94, P = .002) analyses. PORT was associated with significantly improved 5-year OS for patients with 1 (68% vs 58%, P < .001), 2 (52% vs 31%, P < .001), and ≥3 (38% vs 24%, P < .001) NCCN-defined risk factors. Prognostic variables significantly associated with worse OS on multivariable analysis included advanced age, primary tumor size ≥3 cm, high grade, positive margin(s), stage N2-3, level IV/V nodal metastasis, and extranodal extension.

CONCLUSION

PORT for resected ARSCC with adverse pathologic features is associated with significantly improved OS.

Intraoral midline mandibulotomy to improve access for transoral robotic surgery (TORS) base of tongue resection in a retrognathic and microstomic patient

A 74-year-old man was referred to a tertiary academic otolaryngology clinic for evaluation of a left-sided neck mass with unknown primary. Nuclear imaging modalities revealed a primary cancer located at the left tongue base. Further investigation revealed the tumour to be a p16 positive squamous cell cancer with metastatic spread to cervical lymph nodes of multiple levels. The patient was found on initial investigation to have microstomia and a retrognathic mandible, which are typically considered unsuitable for robotic surgery due to difficulties obtaining adequate exposure.The patient underwent bilateral neck dissection, followed by transoral robotic-assisted left base of tongue resection. A midline intraoral mandibulotomy was performed to improve robotic access. Following tumour resection, the mandible was repaired using open reduction with internal plate fixation. Postoperative occlusion was maintained, and the patient recovered well from mandibulotomy with none of the morbidity or cosmetic defects associated with a traditional lip-split approach.

Mandible handling in the surgical treatment of oral squamous cell carcinoma: lessons from clinical results after marginal and segmental mandibulectomy

OBJECTIVE

The aim of this retrospective, single-center study was to analyze long-term results after marginal and segmental mandibulectomies in patients with oral squamous cell carcinoma (OSCC).

STUDY DESIGN

The study included 259 patients treated for OSCC with mandibulectomy between 1996 and 2010. Data acquisition consisted of analysis of operation reports, re-evaluation of histologic bone specimens, and collection of clinical follow-up data.

RESULTS

Of the included patients, 86.5% had received segmental and 13.5% marginal mandibulectomies. Patients who received segmental mandibulectomy generally displayed a higher TNM (tumor-node-metastasis) stage; 47% of patients who received segmental mandibulectomy and 14% of those receiving marginal mandibulectomy showed bone infiltration (pT4 a). Of all patients with bone infiltration, 49% showed an invasive histologic infiltration pattern, and 35% showed an erosive histologic infiltration pattern. We found healthy residual crestal bone height in 43% of all segmental mandibulectomies. Only 8% of all patients were prosthodontically rehabilitated. With regard to prognostic parameters, there was no significant difference between patients receiving marginal mandibulectomy and those receiving segmental mandibulectomy.

CONCLUSIONS

Because healthy residual crestal bone height was found in 43% of all patients who had received segmental mandibulectomies, it is conceivable that a significant number of patients would profit from marginal mandibulectomy, at least in cases of absent or erosive bone infiltration pattern, because the residual crestal bone is functionally stable.

Extended Subtotal Mandibulectomy for the Treatment of Oral Tumors Invading the Mandibular Canal in Dogs-A Novel Surgical Technique

Mandibular tumors in the oral cavity of dogs can be locally aggressive and infiltrative, involving adjacent soft and hard tissues. Tumors that invade the mandibular canal are considered likely to extend rostrally and caudally within that structure due to minimal tissue resistance. When this occurs, a total mandibulectomy is thought to be the treatment of choice as it allows en bloc excision of the mandibular canal. This procedure is technically challenging and time consuming. In the present report we describe a novel technique, the extended subtotal mandibulectomy, as a possible alternative in cases of mandibular body tumors that have invaded the mandibular canal. This technique allows the complete excision of the mandibular canal whilst retaining the coronoid and condylar processes.

Partial mandibulectomy without bony reconstruction in patients with oropharyngeal or mouth cancer

Aim of the study

Resection of tumours of the oral cavity has significant consequences relating to function and aesthetic properties. Advancements in surgical techniques and microvascular surgery have enabled reconstructive outcomes to reach those of pre-surgery levels with good functional and aesthetic results. However, reconstructive options are not without complications.

Material and methods

We report the outcome of 23 patients with large tumours of the oral cavity or floor of the mouth, who underwent resection of the tumour and parts of the mandible without bony reconstruction. The patient population consisted of 19 oropharyngeal carcinomas and four floor of the mouth cancers, all of which had stage cT4 (six female and 17 male patients), and with an average patient age of 59.8 years. The pre- and postoperative ability to open the mouth, level of pain while masticating, mastication function pre and post-surgery, and the aesthetic outcome post-surgery were measured.

Results

The results obtained were deemed pleasantly acceptable by the patients, from aesthetic, functional, and analgesic points of view.

Discussion

A thorough preoperative work up is required and discussion with a multidisciplinary team is a necessity. This treatment option is more acceptable to the patient than would be expected and provides a satisfactory functional and aesthetic outcome. Therefore, we believe that partial mandibulectomy without bony reconstruction is an acceptable management option for a carefully selected group of patients who may not be suitable for the extensive surgery involved with bony reconstruction.

'Doing as little as possible and as much as necessary' - Oncological efficacy of marginal mandibulectomy in resection of oral cavity cancers

BACKGROUND

In carefully selected oral cavity cancers, marginal mandibulectomy is an adequate procedure which achieves good disease control adhering to the principle of "doing as little as possible and as much as necessary".

METHODOLOGY

This was a retrospective study done by reviewing the medical records of all patients who underwent marginal mandibulectomy for resection of oral cavity cancers in our institution during a period of 5 years. Data was collected from medical case records and analyzed.

RESULTS

125 cases underwent marginal mandibulectomy for resection of oral cavity cancers. 88.5% of advanced oral cavity cancers that underwent neoadjuvant chemotherapy followed by marginal mandibulectomy are still disease free. The local recurrence rate was 10.4%. Among cases which recurred, 61.5% were in T2 stage of the disease and 30.8% recurred in buccal mucosa. For lesions on the mandible (26/125), the final histopathology showed bone infiltration in only 12% cases and among them only one recurred. Among 88/125 cases where the lesion was abutting mandible even after stretching mucosa, recurrence was noted only in 11.4% with 3-year overall survival of 79.3%.

CONCLUSIONS

The low recurrence rate following marginal mandibulectomy in our study shows good locoregional control when performed for a lesion close to or abutting alveolar periosteum. In management of advanced oral cavity cancers, neoadjuvant chemotherapy followed by marginal mandibulectomy was effective in achieving significant locoregional control. For superficial lesions on the mandible, marginal mandibulectomy gives adequate margin clearance resulting in long term survival.

Does Different Mandibulectomy (Marginal vs Segmental) Affect the Prognosis in Patients With Oral Squamous Cell Carcinoma?

PURPOSE

It is unclear whether different mandibular surgical methods affect the prognosis of patients with oral squamous cell carcinoma (OSCC). Accordingly, the authors retrospectively compared the prognosis of patients who underwent marginal mandibulectomy (MG) or segmental mandibulectomy (SG) for OSCC and aimed to determine the factors influencing prognosis.

MATERIALS AND METHODS

The authors conducted a retrospective cohort study of 82 patients with OSCC who underwent mandibulectomy at their hospital from January 2001 through January 2015. All patients had a biopsy-confirmed diagnosis of OSCC adjacent to the lower mandible. The local recurrence rate and survival rate after these 2 treatment modalities were analyzed using Kaplan-Meier survival analysis. At univariate and multivariate analyses, the Cox regression model was used to screen risk factors for recurrence, including pathologic grade, pT stage, mandibular involvement, lymph node metastasis, and method of mandibulectomy. Statistical significance was considered when P values were less than .05.

RESULTS

Of the 82 patients, 39 underwent MG and 43 underwent SG. According to statistical analysis, age, gender, pathologic grade, tumor stage, mandibular involvement, and lymph node metastasis were similar between the 2 groups. The 3- and 5-year local recurrence rates were not significantly different between the 2 groups (P > .05). The 3- and 5-year survival rates were not significantly different between the 2 groups (P > .05). Poorly differentiated pathologic type was the only prognostic factor for OSCC at multivariate Cox regression analysis (P = .001).

CONCLUSION

The results of this study suggest that MG is safe for some evaluated patients with OSCC. Of the prognostic factors studied, MG was not associated with worse prognosis; however, poorly differentiated OSCC affected the prognosis for oral carcinoma.

[Imaging for surgical planning : Tumor surgery including reconstructive procedures]

Alongside clinical investigation, imaging is an important diagnostic modality for guiding treatment decisions and particularly for surgical planning in head and neck cancer. The significance and type of imaging depends on localization of the primary tumor. Beside the primary tumor, each imaging procedure must also include the lymph nodes, in order to develop an overall concept of surgical treatment. In addition to the superficial growth of a tumor, it is of utmost importance that its infiltration also be detected by imaging, in order to define the extent of tumor resection and identify potentially necessary reconstructive procedures. The type of imaging needed to understand tumor localization and size, e.g., CT or MRI, depends on the region. In some cases the methods are complementary.

Diagnostic approach to retromolar trigone cancer by multiplanar computed tomography reconstructions

Neoplasms of retromolar trigone have important peculiarities due to their spatial relationships with the surrounding structures. Tumours that involve this area can extend to nearby muscles; adipose spaces; and other anatomic structures, such as the soft palate, the tonsillar fossa, the parapharyngeal space, and the floor of the mouth. In spite of a relatively quick diagnosis, the real extent of these tumours is typically underestimated at clinical examination. Our purpose was to propose a systematic approach to the use of multiplanar computed tomography reconstructions to evaluate normal retromolar trigone anatomy and the main pathways of spread for tumours that arise in this area. To our knowledge, only few reports exist in literature about this topic and none are about the usefulness of multidetector computed tomography and multiplanar reconstructions.

Molecular pathways involved in crosstalk between cancer cells, osteoblasts and osteoclasts in the invasion of bone by oral squamous cell carcinoma

AIMS

This study investigates whether matrix metalloproteinases (MMPs), specifically MMP-2 and MMP-9, interacting with other molecules important in osteoblast differentiation and osteoclastogenesis, could play important roles in the invasion of bone by oral squamous cell carcinoma (OSCC).

METHODS

Supernatant (conditioned medium, CM) was collected from OSCC cell lines (SCC15 and SCC25), and from cultured osteoblasts (hFOB cell line and a primary culture, OB), and used for indirect co-culture: OSCC cells were treated with CM from osteoblasts and vice versa. Zymogenic activities of MMP-2 and -9, and protein quantities of all molecules studied, were detected by gelatine zymography and Western blotting, respectively. Real-time polymerase chain reaction (PCR) analysed mRNA of these molecules. Targeted molecules were examined by immunohistochemistry in tissue sections of bone-invasive OSCCs.

RESULTS

Zymogenic activities of both MMPs were increased in OSCC cells following culture with CM from hFOB: Twist1 protein expression was increased while Runx2 did not alter. The RANKL/OPG ratio, zymogen and protein expression of MMP-9 were increased in hFOB cells cultured with CM from OSCC lines, while zymogen expression of MMP-2 was decreased. Real-time PCR showed generally similar changes in expression of these molecules. All targeted molecules were expressed in invading malignant keratinocytes, and all but OPG were expressed in osteoclasts of clinical samples.

CONCLUSIONS

Crosstalk between different cell types appears to exist in the invasion of bone by OSCC. Understanding and ultimately interfering with the molecules involved may provide therapeutic approaches to inhibit such bone invasion.

Alveolar ridge augmentation in irradiated rabbit mandibles

Oral carcinomas are frequently treated with a nonsegmental mandibulectomy plus radiotherapy. Improving the quality of life of these patients depends on the possibilities for dental rehabilitation. The aim of this study was to increase the alveolar ridge height. Twelve white New Zealand rabbits underwent surgery to produce a 11 x 9 x 7 mm(3) horizontal bicortical full-thickness defect at the alveolar ridge of the left mandible. Six were implanted with a composite associating resorbable collagen membrane filled with micro-macroporous biphasic calcium phosphate granules. After a daily radiation delivery schedule for 4 weeks, a total autologous bone marrow graft was injected percutaneously into the center of the implant. All animals were sacrificed at 16 weeks. Successful osseous colonization was observed in all implants. Significant ridge augmentation was observed (p = 0.0349) in the implanted group compared with the control group. This study contributed to producing an experimental model for oncological mandible defects in rabbits.

Prognostic impact of marginal mandibulectomy in the presence of superficial bone invasion and the nononcologic outcome

BACKGROUND

Treatment of oral cavity cancer may require variable extent of mandibular resection. Marginal mandibulectomy is a controversial technique in providing oncologic resection margin. This study analyzes the efficacy of local oncologic control and the morbidity of marginal mandibulectomy in oral cavity carcinoma. Nononcologic complication of osteoradionecrosis is discussed.

METHODS

A retrospective cohort study analyzed clinicopathologic features of 43 patients with oral cavity cancer who underwent marginal mandibulectomy. Histologic mandibular invasion was examined as a function of local control and contribution to osteoradionecrosis.

RESULTS

Bone invasion was present in 16.3% of patients with marginal mandibulectomy. Local control rates were 85.7% in the bone invasion group and 77.8% in the no bone invasion group (p = .7). Osteoradionecrosis rates were 16.7% and 17.6%, respectively (p = .96). There was no significant difference between the 2 groups.

CONCLUSIONS

Marginal mandibulectomy is oncologically sound in providing a safe resection margin in oral cavity cancer abutting or superficially invading the mandible.

Osteoclast-related cytokines from biopsy specimens predict mandibular invasion by oral squamous cell carcinoma

The aim of this study was to examine the value of osteoclast-related cytokines in biopsy specimens for predicting mandibular invasion by oral squamous cell carcinoma (OSCC). In this retrospective study, biopsy specimens were obtained from 30 patients with OSCC. We observed the expression of seven osteoclast-related cytokines (IL-1α, RANKL, PTHrP, OPG, IL-6, RANK and TNF-α) using immunohistochemical (IHC) staining and of an osteoclast using tartrate-resistant acid phosphatase (TRAP) staining. The results were as follows: i) double-staining and IHC staining for RANKL, PTHrP and IL-1α in biopsy samples had diagnostic potential for predicting mandibular invasion; ii) TRAP-positive monoor multinuclear cells were noted in the biopsy samples; iii) double-positive or -negative findings appeared to reliable indicate whether samples were invasion-positive or invasion-negative. Positive IHC staining for PTHrP, IL-1α or RANKL appeared to typically indicate an invasion-positive lesion. We suggest that the expression of both osteoclasts and osteoclast-related cytokines can be used to predict mandibular invasion.

Marginal mandibulectomy in oral cancer surgery: a 13-year experience

The management of the mandible when dealing with oral cavity cancer is still controversial. In this article, we present our experience with marginal mandibulectomy over a 13-year period. We retrospectively evaluated 56 patients who underwent marginal mandibulectomy between 1990 and 2002. Mean age at surgery was 60.3 + or - 9.5 SD years. Neither intraoperative nor perioperative deaths were observed. Infiltration of the resected bone was detected in only one patient (1.8%). Fracture of the mandible was a complication in only one patient (1.8%). Eight patients (14.3%) presented a local and/or regional recurrence. Distant metastases were diagnosed in two patients (3.6%). The 5-year overall and disease-specific survival rates were 60.7 and 77.3%, respectively. Marginal mandibulectomy allows to conduct the resection in a safe tissue or to excise tumors of the floor of the mouth with a limited involvement of the alveolar periosteum. Whenever the tumor is close to the mandible or when it adheres to the alveolar periosteum, marginal mandibulectomy offers the possibility to perform an oncologically sound procedure.

[Tumors of the oropharynx and oral cavity: MR, CT, PET-CT imaging]

Pretherapeutic imaging plays a central role in the management of tumors of the oropharynx and oral cavity. MR and, to a lesser extent, CT and F-18 FDG PET-CT are the imaging modalities of choice for pretherapeutic work-up of these lesions. Imaging protocols should be simple and reproducible, and should provide the key elements for treatment planning.

Diagnostic accuracy of cone-beam CT in the assessment of mandibular invasion of lower gingival carcinoma: comparison with conventional panoramic radiography

PURPOSE

To evaluate the diagnostic accuracy of cone-beam CT in assessing mandibular invasion by lower gingival carcinoma and compare it with that of panoramic radiography.

PATIENTS AND METHODS

Fifty patients with squamous cell carcinoma of the lower gingiva who were examined by both panoramic radiography and cone-beam CT before surgery were included in this study. Five radiologists used a 6-point rating scale to independently evaluate cone-beam CT and panoramic images for the presence or absence of alveolar bone and mandibular canal involvement by tumor. Using the histopathogical findings as the gold standard, we calculated and compared the area under the receiver operating characteristic curve (Az value) and the sensitivity and specificity of the two imaging modalities.

RESULTS

In evaluations of both alveolar bone and mandibular canal involvement, the mean Az value for cone-beam CT (0.918 and 0.977, respectively) was significantly higher than that for panoramic radiography (0.793 and 0.872, respectively). The mean sensitivity for cone-beam CT (89% and 99%, respectively) was significantly higher than that for panoramic radiography (73% and 56%, respectively). There was no significant difference in the mean specificity. While cone-beam CT could provide high-resolution three-dimensional images, the image quality around the alveolar crest was often hampered by severe dental artifacts and image noise, resulting in difficulties in detecting subtle alveolar invasion.

CONCLUSION

Cone-beam CT was significantly superior to panoramic radiography in evaluating mandibular invasion by lower gingival carcinoma. Its diagnostic value in detecting subtle alveolar invasion, however, may be limited by severe dental artifacts and image noise.

[Surgical treatment options in oropharyngeal cancer]

Therapy of oropharyngeal squamous cell cancer traditionally has been radiation-based, with surgery mainly in reserve. With increasing depth of local infiltration and volume of regional metastases the role of surgery in safeguarding curative chances increases. However, after failed chemoradiation of oropharynx cancer, few patients are cured by salvage surgery. Thus, primary surgery with postoperative radiotherapy may be contemplated if circumtances are favorable. The oropharynx can be approached by transoral, transmandibular or transcervical routes. Primary surgery is increasingly valuable when resultant morbidity is decreased as in the case of more elaborated transoral approaches. Classical approaches also have improved with increasing use of midline mandibulotomy, marginal mandibulectomy, reconstructive surgery, selective neck dissection (ND), and rehabilitation. Elective ND is restricted to levels I or II to III or IV, therapeutic ND is comprehensive (classic or modified radical depending on capsular integrity), and salvage ND is individualized. Surgery, most often followed by radiotherapy, in selected cases of oropharynx cancer is an interesting alternative to chemoradiation, and in advanced disease a facultative but essential part of multimodal therapy.

Magnetic resonance imaging of oropharyngeal cancer

Magnetic resonance imaging (MRI) is a powerful tool for cross-sectional analysis of head and neck anatomy and pathology. This is especially true with regard to oropharyngeal neoplasms, where soft tissue spread, nodal disease, perineural extension, and osseous involvement may significantly alter therapy and prognosis. In this article, we will provide a background on oropharyngeal cancers and MRI techniques and strategies, describing potential advantages of MRI with regard to particular anatomic subsites of the oropharynx. Future imaging trends in perfusion and diffusion MRI of such cancers are also discussed.

Analysis of risk factors of predictive local tumor control in oral cavity cancer

BACKGROUND

Survival in oral cavity squamous cell carcinoma (OSCC) depends heavily on locoregional control. In this study, we sought to determine the independent prognosticators for local tumor control, disease-specific survival (DSS), and overall survival (OS) rates in a series of OSCC patients undergoing radical surgery.

METHODS

We retrospectively reviewed 827 consecutive OSCC patients undergoing radical surgery from January 1998 to March 2005. Postoperative radiotherapy was performed in patients with pT4 tumors, positive lymph node(s), or close margins (< or = 4 mm). Local control rates and survivals were plotted using the Kaplan-Meier method.

RESULTS

On multivariate analysis (MVA), unfavorable prognostic factors for local control were pathological margins < or = 7 mm (P < 0.001), pathological tumor depth > or = 10 mm (P < 0.001), pathological positive lymph node(s) (P = 0.001), and the presence of betel quid chewing (P = 0.012). The same predictors, with the exception of betel quid chewing and pathological positive lymph node(s), were independently associated with DSS and OS in MVA. A prognostic scoring system was formulated by summing up the four significant local control covariates from MVA. Patients with scores of 3-4 had a significantly poorer local control rate compared to patients with scores of 0-2 (score 3 versus score 0-2: P < 0.001; score 4 versus score 0-2: P < 0.001)

CONCLUSIONS

Taken together, our data suggest that pathological margins and pathological tumor depth are major independent prognosticators not only for local tumor control, but also for DSS and OS.