Results of surgical treatment for squamous carcinoma of the lower alveolus: segmental vs. marginal resection

Marginal versus Segmental Mandibulectomy in the Treatment of Oral Cavity Cancer: A Systematic Review and Meta-analysis

Introduction  Oral cavity squamous cell carcinoma (OCSCC) is the most common malignancy in the oral cavity. Two types of mandibular resections have been described: the segmental mandibulectomy and the marginal mandibulectomy. Both may have a different impact over the quality of life, oncological prognosis, and functional or aesthetic result. Objectives  The aim of this study was to systematically explore the literature to determine the survival outcomes and disease control rates in patients who underwent segmental or marginal mandibulectomy for OCSCC with histological evidence of cortical and medullary bone invasion. Data Synthesis  This review involved a systematic search of the electronic databases MEDLINE/PUBMED, Google Scholar, Ovid Medline, Embase, and Scopus including articles from 1985 to 2019. Fifteen articles were included for qualitative analysis and 11 articles were considered for meta-analysis calculations. All of them correspond to retrospective cohort studies. Conclusion  This systematic review reveals the low-level evidence regarding the impact over local control or survival according to the type of mandibulectomy. Our results need to be considered with precaution according to the limited evidence available. We just found difference regarding the 5-year disease-free survival, and a tendency in favor of segmental mandibulectomy was confirmed when medullary invasion was evident.

Marginal or segmental mandibulectomy: treatment modality selection for oral cancer: a systematic review and meta-analysis

Surgery is the most well established mode of initial definitive treatment for the majority of oral cancers. The most important decision in terms of tumour ablation in oral cancers when the jaws are potentially involved is the management of the mandible. The aim of this study was to explore the differences in survival rate and disease control between patients undergoing marginal mandibulectomy and patients undergoing segmental mandibulectomy using a systematic review and meta-analysis approach. A total of 15 cohort studies, including 1672 participants, were identified. Meta-analysis provided weak evidence in favour of segmental mandibulectomy for local control. Segmental mandibulectomy gave 73% better disease-free survival than marginal mandibulectomy when the marrow was invaded (P=0.04). The overall survival rate was evaluated, and no statistically significant difference was found between the two different mandibulectomy approaches, although the results showed a trend in favour of segmental mandibulectomy which could increase the overall survival by 23%. Based on these findings regarding the survival rate and efficacy of disease control, this study indicates that a marginal mandibulectomy may be recommended for cases with no invasion or superficial invasion of the mandibular cortex, and a segmental mandibulectomy may be a more reasonable choice for patients with extensive mandibular cortex invasion or medullary invasion.

Technetium-99m bone scan and panoramic radiography in detection of bone invasion by oral carcinoma

OBJECTIVE

The correct extension of cancer in the bone usually remains undetected on static imaging which may lead to inadequate or over excision. The conventional radiography as well as other anatomical imaging modalities like computed tomography, magnetic resonance imaging often fails to detect functional changes in the bone. However, bone scinitigraphy is highly sensitive in detecting earlier changes in the bone but lack anatomical definition. The purpose of the study was to evaluate the accuracy of combining technetium-99m bone scan and panoramic radiography (Tc scan/PR) over using single diagnostic modality in detection of jaw bone invasion by oral carcinomas. The accuracy of these imaging modalities either alone or in combination were determined by comparing with the histopathological findings.

MATERIALS AND METHODS

Twenty patients with biopsy-proven oral malignant tumors were randomly selected from Oral Medicine and Radiology department over a period of two years. All patients were investigated preoperatively by Tc scan and PR. Lewis - Jones's designed diagnostic criterion was applied on Tc scan/PR to evaluate bone involvement by cancer. To test the accuracy of Tc scan, PR and Tc scan/PR, their results were compared with the histopathological findings of resected specimen.

RESULTS

Hybrid Tc scan/PR had higher specificity, accuracy and positive predictive value (83.3%, 94.7%, 92.8%) than Tc scan alone (50%, 84.2%, 81.2%) and higher sensitivity and negative predictive value (100%, 100%) than PR (69.2%, 55.5%).

CONCLUSION

Combination of Tc scan and PR was more accurate in detecting jaw bone invasion by oral squamous cell carcinoma than Tc scan and PR alone.

The RANKL/RANK system as a therapeutic target for bone invasion by oral squamous cell carcinoma (Review)

Squamous cell carcinomas (SCCs) of the gingiva frequently invade the mandible or maxilla; this invasion is associated with a worse prognosis. The bone destruction associated with carcinomal invasion is mediated by osteoclasts rather than directly by the carcinoma. Therefore, if the cellular and molecular mechanisms by which oral SCC regulates bone invasion were known, it could inform the development of new therapeutic targets. Recently, dysregulation of the functional equilibrium in the receptor activator of NF-κB ligand (RANKL)/RANK/osteoprotegerin (OPG) triad has been shown to be responsible for osteolysis associated with the development of malignant tumors in bone sites. Furthermore, the administration of OPG or soluble RANK prevents bone metastasis by cancer cells. In this review, we discuss recent findings indicating that bone invasion by oral SCC is mediated via RANKL/RANK and may be successfully prevented by RANKL inhibition.

Mandibular conservation in oral cancer

Surgery is one of the established modes of initial definitive treatment for a majority of oral cancers. Invasion of bony or cartilaginous structures by advanced upper aero-digestive tract cancer has been considered an indication for primary surgery on the basis of historic experience of poor responsiveness to radiation therapy [1]. The mandible is a key structure both in the pathology of intra-oral tumours and their surgical management. It bars easy surgical access to the oral cavity, yet maintaining its integrity is vital for function and cosmesis. Management of tumours that involve or abut the mandible requires specific understanding of the pattern of spread and routes of tumour invasion into the mandible. This facilitates the employment of mandibular sparing approaches like marginal mandibulectomy and mandibulotomy, as opposed to segmental or hemimandibulectomy which causes severe functional problems, as the mandibular continuity is lost. Accurate preoperative assessment that combines clinical examination and imaging along with the understanding of the pattern of spread and routes of invasion is essential in deciding the appropriate level and extent of mandibular resection in oral squamous cell carcinoma. Studies have shown that local control rates achieved with marginal mandibulectomy are comparable with that of segmental mandibulectomy. In carefully selected patients, marginal mandibulectomy is an oncologically safe procedure to achieve good local control and provides a better quality of life. This article aims to review the mechanism of spread, evaluation and prognosis of mandibular invasion, various techniques and role of mandibular conservation in oral squamous cell carcinoma.

[On the indications for and morbidity of segmental resection of the mandible for squamous cell carcinoma in the lower oral cavity]

BACKGROUND

Segmental resection of the mandibula in oral cancer surgery leads to both functional and aesthetic problems. The decision to preserve or resect the mandible depends on the vicinity of the lesion to the bone. Consequently, based on the rules of safety margins to all planes that are recommended for soft tissues, each lesion that is closer than 10 mm to the mandible needs resection of the bone.

PATIENTS AND METHODS

To establish data-based treatment modalities, a retrospective study was initiated and the results from all preoperative staging investigations of 152 patients with intraoral squamous cell carcinoma who underwent continuity or marginal resection of the mandible were evaluated. The histological outcome of the resected bone was compared to the staging results. Functional rehabilitation and long-term follow-up including survival rates were evaluated. The study reports on typical complications following segmental resection such as fracture of the reconstruction plate and demonstrates experiences with secondary microsurgical reconstructive surgery.

RESULTS

Mainly in cases of stage T1 and T2 carcinomas which are closer than 10 mm to the bone and clinically do not show any infiltration to the mandible, a marginal resection seems to be adequate. The decision about the extension of mandibular resection can be based on intraoperative cross sectional investigation of the periosteum. The survival rate of patients with intraoral carcinomas close to the mandible who underwent marginal mandibulectomy seems to be the same as in cases of continuity resection. A more conservative management of mandibular resection seems to be adequate and a data-based concept to standardize therapy of mandibular resection is presented.

Patterns of mandibular invasion by gingival squamous cell carcinoma

PURPOSE

This study examined patterns of invasion of lower gingiva cancer into the mandible. Our goal was to clarify the most common routes for gingival squamous cell carcinoma to enter and spread within the mandible.

PATIENTS AND METHODS

The subjects were 176 patients with lower gingival squamous cell carcinoma who underwent mandibulectomy; all tumors were examined histopathologically. The method of mandibulectomy was decided on the basis of conventional plain radiographic and computed tomographic findings.

RESULTS

The tumor extended to the periosteum in 33%, to the cortical bone in 23%, and to the bone marrow in 9% of the patients who underwent mandibular resection. The remaining 35% of our patients had no evidence of mandibular invasion.

CONCLUSION

The area of bone resorption on preoperative clinical and radiographic examinations often disagreed with the extent of mandibular invasion on histopathologic examination.

A study of osteoclast-related cytokines in mandibular invasion by squamous cell carcinoma

The purpose of this study was to analyze the mechanism of bone invasion in carcinoma of the mandibular gingiva. We investigated 38 specimens of lower gingival carcinoma and histopathologically classified them into an invasion group (23 cases) and a non-invasion group (15 cases) on the basis of light microscopy evidence. These specimens were examined using immunohistochemical techniques involving antibodies of parathyroid hormone-related protein (PTHrP), tumor necrosis factor (TNF)-alpha, interleukin (IL)-1alpha, -1beta, -6, -11, -18 and transforming growth factor (TGF)-beta. The invasion group showed a high level of expression of PTHrP, TNF-alpha, IL-6 and IL-11 positive cells (P<0.01 versus non-invasion group). The difference in the levels of expression of IL-1alpha, -1beta, -18 and TGF-beta positive cells was not significant between these two groups. Our results suggest that various cancer-derived cytokines, such as PTHrP, TNF-alpha, IL-6 and IL-11, play an important role in the mechanism of bone invasion associated with lower gingival squamous cell carcinoma.

Influence of marginal and segmental mandibular resection on the survival rate in patients with squamous cell carcinoma of the inferior parts of the oral cavity

AIM

The aim of this retrospective study was to investigate whether radical (segmental resection) or conservative (marginal) resection of mandibular bone influenced patients, survival.

PATIENTS AND METHODS

A series of 136 patients selected for partial mandibular resection for the treatment of squamous cell carcinomas of the lower oral cavity was evaluated retrospectively. Fifty-four patients underwent marginal and 82 cases segmental resection of the mandible. The mean follow-up periods were 91.1+/-30.1 months and 91.5+/-26.2 months, respectively. Data was extracted from the patient records and transferred into a database for statistical evaluation. Results Mean survival was 63.0+/-35.3 months for marginal and 53.1+/-32.3 months for segmental resection. The overall survival rate was analysed according to Kaplan-Meier and the test of significance (Log Rank) which yielded no statistically significant difference in the survival rate between both groups (p=0.1119). Numbers of recurrences, second primaries, metastases and/or postoperative complications were similar in both groups, i.e. no statistically significant differences were observed (ANOVA, Post-hoc Scheffé test). Conclusion In cases with an indication for bone resection, marginal resection may achieve satisfactory control and is as effective as segmental resection.

Marginal mandibulectomy for lateral sulcus tumours

OBJECTIVE

To report a retrospective series of marginal mandibulectomy for cancers of oral cavity, with special reference to squamous cancers of gingival buccal complex.

METHODS

Retrospective record review of 107 patients who underwent marginal mandibulectomy between 1994 and 2001.

RESULTS

Eighty-three marginal mandibulectomies were done for gingivo-buccal complex cancers. Local failure rate was 16%. The 2-year and 5-year disease free survival rates were 69 and 60%, respectively. The local recurrence free survival at the end of 2 and 5 years were 79 and 70%, respectively.

CONCLUSION

In carefully selected patients, marginal mandibulectomy is an oncologically safe procedure to achieve good local control.

Marginal resection for carcinoma of the mandibular alveolus and gingiva where radiologically detected bone defects do not extend beyond the mandibular canal

PURPOSE

The study goal was to investigate the adequacy of marginal resection of the mandibular bone in cases of squamous cell carcinomas of the lower alveolus and gingiva where the radiologically detected bone defect does not extend beyond the mandibular canal.

PATIENTS AND METHODS

Sixty-two patients who have had a mandibulectomy performed with or without preoperative radiotherapy and chemotherapy were the study subjects. This retrospective study investigated the correlation between the preoperative radiographic appearance and histopathologic findings of the excised tissue. The results of the treatments were evaluated.

RESULTS

In the cases with erosive bone defects, the extent of the bone involvement did not exceed the extent of the radiographically detected bone defects. However, in 7 (36.8%) of the cases with moth-eaten type bone defects, the extent of bone involvement exceeded the bone defects detected by radiography. Further, 10 of the 16 cases with no apparent bone defect showed apparent bone involvement by the tumors histologically. There were no differences in the 5-year cumulative survival rate between the marginal resection and segmental groups.

CONCLUSIONS

Marginal resection was effective in controlling mandibular alveolus and gingival cancers when radiologically detected erosive bone defects did not extend beyond the mandibular canal. Marginal resection was inadequate when moth-eaten defects were radiologically detected, except when the bone defects were confined to the alveolar bone.

Evaluation of mandibular invasion by head and neck cancers using99mTc-methylene diphosphonate or99mTc-hydroxymethylene diphosphonate and201Tl chloride dual isotope single photon emission computed tomography

Whether a patient with head and neck cancer has mandibular invasion or not is important in determining the method of resection surgery. But, no modality is adequately reliable when used alone in the evaluation of mandibular invasion. Therefore, to more accurately diagnose mandibular invasion in head and neck cancer, we used a new modality, namely, 99mTc methylene diphosphonate (MDP) or 99mTc hydroxymethylene diphosphonate (HMDP) and 201Tl chloride dual isotope single photon emission computed tomography (Tc/Tl SPECT). The aim of this study is to disclose the usefulness of Tc/Tl SPECT in the assessment of mandibular invasion by head and neck cancers. 99mTc-MDP or -HMDP SPECT (Tc SPECT)s and 201Tl chloride SPECT (Tl SPECT)s were performed in 34 patients with suspected mandibular involvement of head and neck cancer. Thirty of 34 cases underwent both TcMTl SPECT and CT examination. Tc/Tl SPECT fusion images were obtained using the Automatic Registration Tool (ART, TOSHIBA, Japan) system. In the diagnosis of mandibular invasion on Tc/Tl SPECT fusion images, a problem was that the range of Tc and Tl uptake was changed by the condition of display used in the reconstruction and expression of the images. Then, prior to clinical evaluation, to reveal the most appropriate upper window level for display, a phantom study was performed. In a clinical study, the upper window level was set at 40 or 50%, which were verified to be the proper values in the preliminary study. The diagnostic accuracy obtained using Tc SPECT, TcMTl SPECT and CT was compared with the histopathological findings. Tc/Tl SPECT at 40 and 50% upper window level had higher specificity, accuracy, and positive predictive value (73.3%, 85.3%, 81.8%) than Tc SPECT alone (21.4%, 67.6%, 64.5%) and higher sensitivity and negative predictive value (94.7%, 91.7%) than CT (70.6%, 72.2%) for detecting mandibular invasion. Tc/Tl SPECT was a useful diagnostic procedure for the assessment of mandibular invasion by head and neck cancers.

Mandibular invasion in oral squamous cell carcinoma: investigation by clinical examination and orthopantomogram

Assessing the relationship of oral squamous carcinoma with the mandible prior to definitive therapy poses a perplexing problem for the head and neck oncologist. We carried out a prospective open study of 51 (21 female and 30 male; mean age of 53.4 years) patients undergoing mandibular resections for oral squamous cell carcinoma to examine the incidence of mandibular bone invasion and to assess the predictive capabilities of clinical and radiological examination in detecting bone involvement. A detailed clinical examination was followed by radiographic evaluation of mandible for bone invasion. After resection, the mandible was sectioned serially at every cm to find the pathological bone involvement. Sensitivity, specificity, and positive and negative predictive values of clinical and radiological findings were calculated. Specimens from 25 patients (49%) (4 segmental 21 hemi) demonstrated tumour invasion on histological examination. Clinical impression of mandibular invasion showed a sensitivity of 96% and specificity of 65%, whereas radiological examination had a sensitivity of 92% and specificity of 88%. When considered together, clinical and radiological examinations were able to detect all the cases of bone invasion, but specificity was only 58%. This study advocates careful correlation of clinical and radiological findings prior to definitive therapy, as clinical examination tends to over diagnose bone invasion in tumours adjacent to the mandible. The specificity of imaging was also found to be low pointing towards the need for more specific diagnostic tools in doubtful cases. Aggressive surgical therapy, namely segmental or hemi resection of mandible is warranted in case of tumours of the lower alveolus with definite bone invasion. In case of carcinomas of the buccal mucosa and tongue the mandibular resection can be limited to that required for clearance of margins provided the radiology is negative.

Marginal and segmental mandibulectomy in patients with oral cancer: a statistical analysis of 106 cases

PURPOSE

The treatment of oral squamous cell carcinoma may require mandibular resection to secure adequate margin. This bone resection often is segmental or marginal mandibulectomy. The purpose of this work was to evaluate the local control and survival after surgical treatment of oral cancer, according to these 2 different mandibular resection procedures.

PATIENTS AND METHODS

We conducted a retrospective study of a 20-year cohort of 106 patients who underwent marginal or segmental mandibulectomy for oral cancer. All patients had a biopsy-confirmed diagnosis of squamous cell carcinoma involving either the floor of the mouth, mandibular gingiva, retromolar trigone, tongue, buccal mucosa, or oropharynx. The type of mandibular resection and treatment outcome were compared, using an univariate analysis by the Pearson chi(2) test, logistic regression model for multivariate analysis, and Kaplan-Meier method to determine survival.

RESULTS

The 5-year observed survival rate was 60.35%. The presence of histologic mandibular invasion increased the local recurrence rate. Early tumor stages (P =.02) were found to be associated with decreased local recurrence rates. Our findings indicate that tumor stage and size of mandibulectomy are more important than the type of mandibulectomy in predicting histologic bone involvement. The cases treated with a greater than 4 cm bone resection showed a lower survival rate than those treated with less than 4 cm mandibulectomy (P =.01). Patients in advanced stages (P =.006) and those with surgical margin (P =.0001) or the bone (P =.003) affected by the tumor showed a statistically significant lower survival rate. However, no statistically significant differences were found between patients treated by marginal or segmental mandibulectomy.

CONCLUSIONS

Among the prognostic factors studied, the status of the surgical resection margin, the bony involvement and the size of mandibulectomy affected the prognosis for oral carcinoma. Mandibular conservation surgery is oncologically safe for patients with squamous carcinoma in early stages. The marginal technique was not associated with worse prognosis.

Mandibular bone invasion by gingival carcinoma on dental CT images as an indicator of cervical lymph node metastasis

OBJECTIVES

To evaluate the significance of mandibular bone invasion by gingival carcinoma revealed by reformatted dental CT images as a prognostic indicator of cervical metastasis.

METHODS

Thirty-two patients with squamous cell carcinoma of the lower gingiva were examined by dental CT. Cervical metastases and survival rates of these patients were analysed in relation to their clinical characteristics, histologic grading based on gingival biopsy, and mandibular bone invasion using reformatted dental CT imaging diagnoses prior to surgery. The dental CT images were classified into four types: Class I, no bone invasion; Class II, invasion confined to the alveolus; Class III, invasion extending between the alveolus and the mandibular canal; and Class IV, invasion beyond the mandibular canal.

RESULTS

Logistic multivariate regression analysis showed that bony invasion identified on dental CT images was a significant prognostic factor in cervical metastases (P=0.028). The 5-year overall survival rates of Classes I, II, III, and IV were 100% (n=9), 76.2% (n=9), 71.4% (n=7), and 28.6% (n=7), respectively.

CONCLUSIONS

The evaluation of mandibular bone invasion using dental CT images is useful as a prognostic indicator of cervical metastasis for patients with gingival carcinoma.

Preoperative assessment for and outcomes of mandibular conservation surgery

INTRODUCTION

The role of marginal mandibulectomy and other conservative resective procedures for patients with early cortical mandibular invasion from squamous carcinoma of the oral cavity remains poorly defined. The purpose of this retrospective study was to evaluate the efficacy of preoperative assessment for bone invasion and the outcomes of different mandibular resective procedures that preserve mandibular continuity.

METHODS

The charts of 222 patients treated at the University of Texas M. D. Anderson Cancer Center between 1960 and 1990 were reviewed. All patients had a biopsy-confirmed diagnosis of squamous carcinoma involving either the lower gingiva, floor of mouth, oral tongue, or retromolar trigone. All patients had a surgical resection that involved removing less than a segment of the mandible. Patient data were analyzed to determine the usefulness of preoperative assessment and outcomes of therapy.

RESULTS

Clinical evaluation of mandibular bone invasion was more sensitive than radiologic evaluation, whereas radiologic assessment was more specific and had a higher reliability index. The overall local and regional recurrence and distant metastasis rates for all T stages were 14.4%, 18.0%, and 2.7%, respectively. Sixty-nine point eight percent of all patients were without evidence of disease 2 years after treatment.

CONCLUSIONS

Mandibular conservation surgery is oncologically safe for patients with early mandibular invasion. Accurate preoperative assessment that combines clinical examination and radiographic evaluation is better than either modality alone, but clinical judgment is still necessary for proper patient selection.

Outcome of squamous cell carcinoma of the gingiva: a follow-up study of 83 cases

BACKGROUND

Squamous cell carcinomas of the gingiva are relatively rare tumours. Standard treatment is based on surgery and radiotherapy. The extent of bone involvement affects mandibulectary indications.

PURPOSE

A retrospective review of squamous cell carcinomas of the gingiva was performed to evaluate the incidence of mandibular or maxillary bone involvement. Indications for marginal and segmental bone resections are specified.

MATERIAL

From 1985 to 1996, 83 patients with squamous cell carcinoma of the gingiva were treated at the Department of Surgery (Institut Bergonié, Bordeaux, France) and at the Department of Maxillofacial and Plastic Surgery (Centre Hospitalier Universitaire, Bordeaux, France). Forty-three underwent surgery plus postoperative radiotherapy. Twenty-two had flap reconstructions. Clinical evaluation and panorex roentgenography were the means used to evaluate bony invasion and to decide on the extent of bone resection.

METHODS

A retrospective review of 83 consecutive patients was performed. This series is unusual in its homogeneity: surgery was performed by only two individuals and the radiotherapy was the responsibility of just two physicians. Outcome was calculated using the Kaplan-Meier method.

RESULTS

Primary local control was achieved in 72 patients (87%). Overall survival and rate of recurrence were comparable to those of other squamous cell carcinomas of the oral cavity and oropharynx.

CONCLUSION

Surgical resection continues to be the mainstay of treatment and this study tends to confirm the validity of modified neck dissection and marginal bone resection in suitably selected patients.

Prognostic implications of mandibular invasion in oral cancer

BACKGROUND

Mandibular invasion alters the clinical staging and management of oral epidermoid carcinoma on the assumption that underresection of mandibular bone invaded by tumor can result in disease progression and poor outcome.

METHODS

Cox's proportional hazard model was used to assess the effect of mandibular invasion on recurrence-free survival in 107 patients with squamous cell carcinoma of the oral cavity after controlling for the potential confounding effect of positive margins, tumor size, nodal status, and type of resection.

RESULTS

Mandibular invasion was characterized as none (n = 59), focal (n = 25), or deep (n = 23). Relapse-free survival at 60 months by the Kaplan Meier product limit method for the none, focal, and deep invasion groups was 61%, 73%, and 46% respectively (p =.28). Variables influencing disease recurrence were positive margins, size >2 cm, N2 and N3 nodal disease, and marginal vs segmental mandibular resection. Mandibular invasion was not a significant risk factor for disease recurrence with an adjusted hazard ratio for deep invasion vs focal or no invasion of 1.0 (95% CI = 0.5, 2.2; p = 1.00).

CONCLUSIONS

Detection of bone invasion, particularly in small tumors, may not be as critical to surgical planning as previously expected. The necessity for and extent of bone resection should be determined by the objective of achieving an adequate surgical margin and not the presence of bone invasion per se.

Histological pattern of mandibular invasion by oral squamous cell carcinoma

OBJECTIVE

Mandibular invasion by oral squamous cell carcinoma may progress by either an infiltrative or an erosive histological pattern. The infiltrative pattern is marked by nests and cords of tumor cells along an irregular tumor front, and the erosive pattern exhibits a broad, pushing tumor front. The objectives of this study were 1) to define the characteristics associated with each histological pattern of mandibular invasion, 2) to assess the relationship between pattern of invasion and clinical outcome as measured by death with disease and disease presence at last follow-up, and 3) to determine whether the cell cycle markers cyclin D1 and Ki-67 are associated with the histological pattern of invasion or are predictive of outcome.

STUDY DESIGN

Retrospective study of 68 patients with mandibular invasion by oral cavity squamous cell carcinoma treated by mandibulectomy.

METHODS

The clinical records, pathology reports, and original H&E-stained slides were reviewed for each patient. Immunohistochemical staining of cyclin D1 and Ki-67 was performed on slides cut from the paraffin blocks of these patients' specimens.

RESULTS

The parameters found to be significantly associated with the infiltrative pattern of mandibular invasion included higher tumor grade, medullary space invasion, positive bone or soft tissue margins, history of previously failed treatment, and postoperative tumor recurrence. The infiltrative pattern had a positive bone margin rate of 47.6% and a primary site recurrence rate of 52.6%. In contrast, the erosive pattern had a positive bone margin rate of 4.9% and a primary site recurrence rate of 16.7%. The infiltrative pattern of invasion gave a fourfold increased risk of death with disease and disease presence at last follow-up in univariate and multivariate analyses when compared with the erosive pattern of invasion. The 3-year disease-free survival was 30% for the infiltrative pattern and 73% for the erosive pattern. The median disease-free survival was 1.5 years for the infiltrative pattern and 5.5 years for the erosive pattern. There was no correlation between cyclin D1 or Ki-67 staining and invasion pattern or clinical outcome.

CONCLUSIONS

The infiltrative pattern of mandibular invasion by oral squamous cell carcinoma is correlated with a significantly worse prognosis when compared with the erosive pattern of invasion. The infiltrative pattern clearly exhibits a more aggressive behavior with an increased likelihood of positive margins, recurrence, death with disease, and shorter disease-free survival. We recommend that pathologists routinely comment on the histological pattern of invasion when reviewing oral squamous cell carcinoma with mandibular invasion.

A comparison of segmental and marginal bony resection for oral squamous cell carcinoma involving the mandible

PURPOSE

This study reviews the accuracy of preopertive diagnosis of mandibular invasion by oral squamous cell carcinoma and assesses the role of marginal resection of the mandible in its treatment.

PATIENTS AND METHODS

A retrospective study of a 5-year cohort of 46 patients who underwent mandibular resection for previously untreated oral squamous cell carcinoma was done. Data evaluated included age; sex; site and stage of cancer; preoperative clinical, panoramic, and computed tomography (CT) evaluations; and histologic findings on the resection specimen. The type of mandibular resection (segmental vs marginal) and treatment outcome also were compared.

RESULTS

Clinical examination, panoramic radiographs, and CT scans were 78.5% to 82.6% accurate in diagnosing mandibular invasion by squamous carcinoma. Clinical examination and panoramic radiographs are more sensitive than CT scans (86.6% vs 53%), but CT scans were more specific (92.5% vs 80%). The mandible was involved in 65% of patients with segmental resection and 7.6% of patients who had a marginal resection. Nineteen percent of the patients in the marginal resection group died of their oral cancer, two of five patients with local recurrence. Ten percent of patients in the segmental resection group died of oral cancer; no local recurrences were seen.

CONCLUSION

There is no completely accurate method of diagnosing bony invasion of the mandible by oral squamous cell carcinoma. A combination of clinical examination, plain radiographs, and computed tomography (CT) scans may improve the diagnosis. Marginal resection is best reserved for cancers close to the bone with no invasion, minimal cortical invasion, or with early "arrosive" invasion. It is best in the symphysis region. Careful case selection will allow a favorable oncologic outcome with preservation of the mandibular contour.

Changing trends in the management of carcinoma of the oral cavity and oropharynx

Two groups of patients with squamous cell carcinoma of the oral cavity and oropharynx treated by radical surgery were studied. Special emphasis was placed on analysing changing trends in reconstruction and the management of the mandible and their influence on complication rates, length of hospital stay and tumour control rates. Group 1 consisted of 97 patients treated between 1980 and 1984 and Group 2 consisted of 153 patients treated between 1987 and 1991. Anatomical distribution of cancers and clinical stages were similar in the two groups. The major trends identified were: (i) the increasing use of free flaps for reconstruction (0 in Group 1, 41% in Group 2); (ii) more conservative mandibular resection and the increasing use of mandibular swing procedures (1% in Group 1, 16% in Group 2) rather than segmental mandibular resection (44% in Group 1, 13% in Group 2); (iii) fewer procedures per patient (2.6 per patient in Group 1, 1.2 per patient in Group 2); and (iv) a decrease in mean duration of hospital stay from 34 to 16 days and fewer complications. Patients in Group 2 also had a lower rate of local recurrence of cancer when compared with patients in Group 1 (19 vs 29%).

A functional evaluation of patients treated for oral cancer. A prospective study

The oral function of 81 consecutive patients with intraoral squamous cell carcinoma was assessed at diagnosis and during the follow-up 1-2 years after diagnosis. Patients received either radiotherapy, surgery, or radiotherapy and surgery. Speech function and tongue mobility were better among patients who received radiotherapy alone than among patients treated with surgery or combined therapy. Subjective complaints about mucositis, poor dental status, and loss of teeth were most pronounced among patients who received radiotherapy. Patients with tumor recurrence reported a poorer quality of life and found it more difficult to accept their treatment than patients with successful primary therapy. Patients with stage I tumors, notably patients treated with surgery, felt that their quality of life was good after treatment.

Marginal mandibulectomy for carcinoma of the floor of the mouth

Resection of primary tumors of the floor of the mouth mandates consideration of the management of the mandible which may be either involved by direct invasion or by close proximity. Segmental mandibulectomy can usually be performed when the tumor is either massive or directly invading the mandible. However, the cosmetic and functional results of segmental mandibulectomy are unsatisfactory. Whenever the tumor is close to the mandible or adherent to the periosteum, consideration should be given to marginal mandibulectomy. Over a period of 8 years, we have treated 65 patients with carcinoma of the floor of the mouth. Of these, 22 underwent marginal mandibulectomy. The number of patients staged T1, T2, and T3 were 4, 13, and 5, respectively. Most had oblique marginal mandibulectomy including the resection of the upper rim and medial cortex of the mandible. Vertical or horizontal mandibulectomy was rarely used. In each patient the preoperative workup included dental X-rays, panoramic films, and computerized tomography (CT) scan of the head and neck. The decision as to the extent of mandibulectomy was made primarily based on the clinical judgement. Seven patients underwent marginal mandibulectomy through the open mouth. However, in the remaining 15 patients, the cheek flap approach was utilized. The defect following marginal mandibulectomy was reconstructed either with split thickness skin graft, tongue flap, or myocutaneous flap. Small defects were left open to heal by granulation and secondary intention. Split thickness skin grafts healed very well over the surface of resected mandibles. Good local tumor control was achieved at the primary site and the functional and cosmetic results were excellent.