Squamous cell carcinoma of the floor of mouth: a 20-year review

Population-based study of treatment outcomes in squamous cell carcinoma of the retromolar trigone

BACKGROUND

Carcinoma of the retromolar trigone is relatively uncommon. High rates of local recurrence account for a relatively poor prognosis.

STUDY DESIGN

A population-based historical cohort of 76 cases with biopsy-proven squamous cell carcinoma of the retromolar trigone were studied as a case series. Kaplan-Meier survival curves and log rank test were used for statistical analysis.

RESULTS

The mean age was 67.2 years. Fifty-six patients were male, 45% had T1 or T2 tumors, and 61% were staged as N0. Treatment included radiotherapy in 35%, surgery alone in 26%, surgery and radiotherapy in 23%, and 16% received palliative treatment. The absolute and disease-specific survivals at 5 years were 51.4% and 67.7%, respectively. In patients treated with surgery, the resection margin status predicted the overall 5-year survival (P = .027), with 75% of patients with negative margins surviving 5 years versus a survival of 0% of patients with involved margins.

CONCLUSIONS

Squamous cell carcinoma of the retromolar trigone has a poor survival rate for early-stage disease. Adequate surgical margins can improve survival.

Current surgical treatment of squamous cell carcinoma of the head and neck

Historically treatment of head and neck cancers involved surgical resection followed by radiation therapy for advanced tumors. Concurrent chemoradiation therapies have shown equal survival to surgical resection with better preservation of function. However, concurrent therapy does entail significant morbidity, and recent advances have been used to minimize that morbidity. Newer tumor specific medical therapies are anticipated to be less toxic while maintaining a high degree of efficacy. For resectable cancer, transoral laser microsurgery is a new trend in surgery for complete resection of tumors with preservation of function. Advanced reconstructive techniques that allow free transfer of soft tissue and bone from all over the body improve the functional and aesthetic outcomes following major ablative surgery. With successful surgical reconstruction, dental and prosthetic rehabilitation choices are enhanced. Advances in rehabilitation of speech following removal of the larynx have improved the quality of life post-laryngectomy patients. With these newer therapies and methods of reconstruction, each patient needs to be carefully evaluated to maximize the possibility of cure and level of function, and minimize the morbidity associated with treatment. Combined chemotherapy and radiation protocols are associated with increased acute and chronic toxicities that may affect the quality of life due to the impact upon oral disease and oral function. Oral care providers must be aware of advances in cancer management and implications for patient care to effectively care for these patients.

Hyaluronan-CD44 interaction with leukemia-associated RhoGEF and epidermal growth factor receptor promotes Rho/Ras co-activation, phospholipase C epsilon-Ca2+ signaling, and cytoskeleton modification in head and neck squamous cell carcinoma cells

In this study we have examined the interaction of CD44 (a major hyaluronan (HA) receptor) with a RhoA-specific guanine nucleotide exchange factor (leukemia-associated RhoGEF (LARG)) in human head and neck squamous carcinoma cells (HNSCC-HSC-3 cell line). Immunoprecipitation and immunoblot analyses indicate that CD44 and the LARG protein are expressed in HSC-3 cells and that these two proteins are physically associated as a complex. HA-CD44 binding induces LARG-specific RhoA signaling and phospholipase C epsilon (PLC epsilon) activity. In particular, the activation of RhoA-PLC epsilon by HA stimulates inositol 1,4,5-triphosphate production, intracellular Ca2+ mobilization, and the up-regulation of Ca2+/calmodulin-dependent kinase II (CaMKII), leading to phosphorylation of the cytoskeletal protein, filamin. The phosphorylation of filamin reduces its interaction with filamentous actin, promoting tumor cell migration. The CD44-LARG complex also interacts with the EGF receptor (EGFR). Most importantly, the binding of HA to the CD44-LARG-EGFR complex activates the EGFR receptor kinase, which in turn promotes Ras-mediated stimulation of a downstream kinase cascade including the Raf-1 and ERK pathways leading to HNSCC cell growth. Using a recombinant fragment of LARG (the LARG-PDZ domain) and a binding assay, we have determined that the LARG-PDZ domain serves as a direct linker between CD44 and EGFR. Transfection of the HSC-3 cells with LARG-PDZcDNA significantly reduces LARG association with CD44 and EGFR. Overexpression of the LARG-PDZ domain also functions as a dominant-negative mutant (similar to the PLC/Ca2+-calmodulin-dependent kinase II (CaMKII) and EGFR/MAPK inhibitor effects) to block HA/CD44-mediated signaling events (e.g. EGFR kinase activation, Ras/RhoA co-activation, Raf-ERK signaling, PLC epsilon-mediated inositol 1,4,5-triphosphate production, intracellular Ca2+ mobilization, CaMKII activity, filamin phosphorylation, and filamin-actin binding) and to abrogate tumor cell growth/migration. Taken together, our findings suggest that CD44 interaction with LARG and EGFR plays a pivotal role in Rho/Ras co-activation, PLC epsilon-Ca2+ signaling, and Raf/ERK up-regulation required for CaMKII-mediated cytoskeleton function and in head and neck squamous cell carcinoma progression.

Functional relevance of urinary-type plasminogen activator receptor-alpha3beta1 integrin association in proteinase regulatory pathways

Squamous cell carcinoma of the oral cavity is characterized by persistent, disorganized expression of integrin alpha3beta1 and enhanced production of urinary-type plasminogen activator (uPA) and its receptor (uPAR) relative to normal oral mucosa. Because multivalent aggregation of alpha3beta1 integrin up-regulates uPA and induces a dramatic co-clustering of uPAR, we explored the hypothesis that lateral ligation of alpha3beta1 integrin by uPAR contributes to uPA regulation in oral mucosal cells. To investigate mechanisms by which uPAR/alpha3beta1 binding enhances uPA expression, integrin-dependent signal activation was assessed. Both Src and ERK1/2 were phosphorylated in response to integrin aggregation, and blocking Src kinase activity completely abrogated ERK1/2 activation and uPA induction, whereas inhibition of epidermal growth factor receptor tyrosine kinase activity did not alter uPA expression. Proteinase up-regulation occurred at the transcriptional level and mutation of the AP1 (-1967) site in the uPA promoter blocked the uPAR/integrin-mediated transcriptional activation. Because uPAR is redistributed to clustered alpha3beta1 integrins, the requirement for uPAR/alpha3beta1 interaction in uPA regulation was assessed. Clustering of alpha3beta1 in the presence of a peptide (alpha325) that disrupts uPAR/alpha3beta1 integrin binding prevented uPA induction. Depletion of cell surface uPAR using small interfering RNA also blocked uPA induction following integrin alpha3beta1 clustering. These results were confirmed using a genetic strategy in which alpha3 null epithelial cells reconstituted with wild type alpha3 integrin, but not a mutant alpha3 unable to bind uPAR, induced uPA expression upon integrin clustering, confirming the critical role of uPAR in integrin-regulated proteinase expression. Disruption of uPAR/alpha3beta1 binding using peptide alpha325 or small interfering RNA blocked filopodia formation and matrix invasion, indicating that this interaction stimulates invasive behavior. Together these data support a model wherein matrix-induced clustering ofalpha3beta1 integrin promotes uPAR/alpha3beta1 interaction, thereby potentiating cellular signal transduction pathways culminating in activation of uPA expression and enhanced uPA-dependent invasive behavior.

Oral squamous cell carcinoma cells induce osteoclast differentiation by suppression of osteoprotegerin expression in osteoblasts

The invasion of oral squamous cell carcinoma (SCC) cells into the mandibular bone is a common clinical problem. It has been reported that BHY cells, a human oral SCC cell line, are capable of invading mandibular bone of nude mice. These results led us to examine possible mechanisms of osteoclastogenesis induced by BHY cells using in vitro culture systems. When BHY cells were cocultured with mouse bone marrow cells (BMCs), only few osteoclasts were formed, even though BHY cells express the receptor activator of NF-kappaB ligand (RANKL). However, adding BHY cells to a coculture of mouse primary osteoblasts (POBs) and BMCs markedly induced osteoclastogenesis in the absence of osteotropic factors. Furthermore, another oral SCC cell line, HSC-2, which does not express RANKL, also induced osteoclastogenesis in our cocultures. These effects were significantly, but not completely, inhibited by adding osteoprotegerin (OPG). In addition, we also found that TNFalpha released from these cells partially contributes to osteoclastogenesis via a RANKL-independent mechanism. Adding BHY or HSC-2 cells suppressed mouse OPG mRNA expression and protein production by POBs in cocultures of POBs and human oral SCC cells. This finding is consistent with the result that BHY cells and HSC-2 cells did not enhance osteoclastogenesis in cocultures of BMCs and POBs from OPG-deficient mice. Immunohistochemical analysis showed a reduction of OPG expression in osteolytic lesions as compared to normal lesions from oral SCC patients. Therefore, oral SCC-induced suppression of OPG expression in POBs appears critical for osteoclastogenesis, rather than expression of RANKL in SCC cells.

Definition of a region of loss of heterozygosity at chromosome 11q23.3-25 in head and neck squamous cell carcinoma using laser capture microdissection technique

To date, loss of heterozygosity (LOH) studies on HNSCC have had limited success in identifying a confined region of loss on chromosome 11q partially due to the heterogeneous nature of tumor tissue examined. Additionally, little is known about the role of the 11q allelic deletion in HNSCC tumorigenesis and current reports are conflicting. The aim of this study was to better define LOH at distal 11q by using combination of a pure cell population procured by laser capture microdissection (LCM) and subsequent sensitive PCR amplification of polymorphic microsatellites. This study analyzed HNSCC for LOH using a panel of 5 microsatellite markers spanning 11q23-25. Thirty-four paired DNA samples from tumor and autologous normal tissue were harvested by LCM technique to ensure a pure cell population for PCR amplification. Approximately 2000 to 3000 cells were procured from each sample. Twenty-one of 34 cases (62%, P < 0.001) showed LOH on at least one of the loci examined. The highest frequency of LOH was found at the 11q23.3-25 segment, with 44% at marker D11S968 and 35% at marker D11S1316. A distinct novel region of frequent LOH at 11q23.3-25, defined by D11S1316 and D11S968, was identified. No allelic loss was found in any normal squamous tissue samples. To study LOH in HNSCC, combination of pure cell population procurement by LCM and sensitive PCR provides a more accurate approach than the conventional method using a bulk of heterogeneous tissue. A novel region of LOH at 11q23.3-25 was defined. LOH in this region may harbor putative tumor suppressor gene(s) critical for HNSCC. Furthermore, these allelic losses were not found in any non-neoplastic squamous tissue samples, clarifying prior discrepant data.

Current treatment options in squamous cell carcinoma of the oral cavity

Oral cavity SCC remains a significant health problem and requires a multidisciplinary approach. Treatment with surgery alone or in combination with adjuvant radiotherapy for more advanced lesions is the standard of care. Major advances have been made in surgical approaches,reconstructive options, and the rehabilitation of patients who have oral cavity SCC. These advances have significantly improved disease-specific outcome and quality of life. The future may lie in the development of treatment regimes that combine early detection with organ preservation and result in improved cure rates and quality of life.

Relevance of positive margins in case of adjuvant therapy of oral cancer

Positive or clean surgical margins are of great prognostic interest in the surgical treatment of oral and oropharyngeal cancer with poor survival of patients burdened with positive margins. The impact of postoperative treatment modalities on the survival of these patients is debated. The relevance of positive margins was investigated in three patient populations (a group treated by surgery only, a group with postoperative polychemotherapy, and a group with a multi-modality treatment comprising postoperative radiation with concurrent chemotherapy) which were compared retrospectively. Patients treated with adjuvant regimens following resection in healthy margins had a survival advantage as compared to the surgery only group possibly due to less local relapses and longer relapse latencies. Overall disease-free survival was better in the groups with adjuvant therapy irrespective of free or positive margins. Survival rates following positive surgical margins were worse in all three groups as compared to the respective subgroups with healthy margins. A second resection in patients with positive margins, executed in the group with postoperative radiation with concurrent chemotherapy, did not result in survival improvement. Therefore, radical resection at initial surgery in healthy and clear margins remains indispensable in multi-modality treatment strategies involving surgery. The combination of healthy margins and adjuvant treatment seems to be most favorable for patient survival.

The status of the deep surgical margins in tongue and floor of mouth squamous cell carcinoma and risk of local recurrence; an analysis of 68 patients

The objective of this study is to retrospectively assess the clinical relevance, i.c. the event of a local recurrence, in patients surgically treated for tongue and floor of mouth squamous cell carcinoma when tumour cell are observed histopathologically at a distance of less than 0.5 cm. Furthermore, the pattern of invasion and the presence or absence of perineural spread were recorded. A total of 68 patients, surgically treated because of a tongue or floor of mouth squamous cell carcinoma, were examined. Patients in whom any degree of epithelial dysplasia was observed in the mucosal surgical margins had been excluded beforehand. Local recurrence occurred in 2 out of 30 patients with a free surgical margins >0.5 cm and in 3 out of 38 patients with a free surgical margin <0.5 cm, the difference being not statistically significant. Apparently, the presence of tumour cells within a distance of less than 0.5 cm, but not into the deep surgical margin, does not necessarily seem to require additional treatment. The pattern of invasion and the presence or absence of perineural spread were not significantly related with local recurrence either.

Oral cancer treatment

Oral cancer is the sixth most common cancer in the world, and it continues to represent a serious public health problem. Oral cancer is a preventable disease, related to behavioral and lifestyle factors, including tobacco and alcohol. Prevention and early detection of oral cancer remain the goals of national efforts to reduce the impact of this disease on the public. Surgical treatment is the mainstay of therapy for patients with oral cancer, particularly in advanced stages of cancer. External beam radiation therapy and brachytherapy have been used successfully as the primary modality for treating patients with early stage oral cancer, and they are the standard of care for use as adjuvant therapy in postoperative cases of patients with advanced stage oral cancer. There is an emerging trend for the use of chemotherapy in combination with radiation therapy and surgery for patients with advanced, recurrent, and metastatic head and neck cancer, although evidence is limited regarding survival benefit when used for treating patients with oral cavity carcinoma. Any report on the treatment of oral cancer is incomplete without consideration of functional and aesthetic outcomes, particularly addressing speech, swallowing, masticatory efficiency, and dental rehabilitation. Future generations will continue to fight these dreadful diseases until scientists and clinicians are provided the opportunities to expand efforts to prevent, detect (early), and eradicate oral and other head and neck cancers.

Primary chemotherapy in resectable oral cavity squamous cell cancer: a randomized controlled trial

PURPOSE

Prognosis of patients with advanced oral cavity cancer is worth improving. Chemotherapy has been reported to be especially active in oral cavity tumors. Here we repeat the results of a randomized, multicenter trial enrolling patients with a resectable, stage T2-T4 (> 3 cm), N0-N2, M0 untreated, squamous cell carcinoma of the oral cavity.

PATIENTS AND METHODS

Patients were randomly assigned to three cycles of cisplatin and fluorouracil followed by surgery (chemotherapy arm) or surgery alone (control arm). In both arms, postoperative radiotherapy was reserved to high-risk patients, and surgery was modulated depending on the tumor's closeness to the mandible. Patients' accrual was opened in 1989 and closed in 1999. It included 195 patients.

RESULTS

In the chemotherapy arm, three toxic deaths were recorded. No significant difference in overall survival was found. Five-year overall survival was, for both arms, 55%. Postoperative radiotherapy was administered in 33% of patients in the chemotherapy arm, versus 46% in the control arm. A mandible resection was performed in 52% of patients in the control arm, versus 31% in the chemotherapy arm.

CONCLUSION

The addition of primary chemotherapy to standard surgery was unable to improve survival. However, in this study, primary chemotherapy seemed to play a role in reducing the number of patients who needed to undergo mandibulectomy and/or radiation therapy. Variations in the criteria used to select patients for these treatment options may make it difficult to generalize these results, but there appears to be room for using preoperative chemotherapy to spare destructive surgery or radiation therapy in patients with advanced, resectable oral cavity cancer.

Loss of adhesion-regulated proteinase production is correlated with invasive activity in oral squamous cell carcinoma

BACKGROUND

Oral squamous cell carcinoma (OSCC) is the most common malignancy of the oral cavity. However, the cellular and biochemical factors that underlie locoregional and distant spread of the disease are poorly understood. Invasion of OSCC requires multiple cellular events including dissolution of cell-cell junctions, basement membrane attachment, extracellular matrix proteolysis, and migration.

METHODS

We evaluated these properties in vitro using premalignant gingival keratinocytes (ppl26) and two OSCC lines (SCC15 and SCC68). Expression of adhesion molecules integrins and cadherins, cytoplasmic intermediate filaments (IF) vimentin and keratin as well as matrix degrading proteins were evaluated. Moreover, regulation of protease production by adhesion molecules was tested.

RESULTS

All cell lines contained comparable levels of the epithelial cell-cell adhesion molecule, E-cadherin. Differential expression of cytoplasmic IF was evident between premalignant pp126 cells and OSCC cell lines. Expression levels of the alpha3beta1 integrin, utilized for attachment to laminin-5 and other matrix proteins, was high in SCC68 cells, moderate in SCC15 cells, and low in ppl26 cells. alpha3beta1 integrin clustering up-regulates expression of urinary-type plasminogen activator (uPA) in ppl26 cells via a mechanism involving ERK activation. Both ppl26 and SCC15 cells were responsive to alpha3beta1 clustering, resulting in enhanced uPA expression. However, basal uPA levels were high in SCC68 cells and integrin clustering did not further stimulate uPA production. ERK was constitutively activated in SCC68 cells and treatment of cells with an inhibitor of ERK activation (PD98059) reduced uPA expression. Consistent with the enhanced proteolytic potential, SCC68 cells readily penetrated Matrigel and invasion was blocked by an anticatalytic uPA antibody.

CONCLUSIONS

These data suggest that loss of adhesion-regulated proteinase production may lead to elevated pericellular proteinase activity and coincident alterations in cytoskeletal IF protein expression, thereby contributing to the invasive potential of OSCC.

Tenascin and beta 6 integrin are overexpressed in floor of mouth in situ carcinomas and invasive squamous cell carcinomas

Floor of the mouth squamous cell carcinomas exhibit many characteristics that suggest they represent a distinct biological subset within head and neck tumors. The features of preinvasive lateral intraepithelial spread, high rate of conversion of intraepithelial neoplasia to invasive carcinoma, and high incidence of occult metastases, suggest the importance of motility-associated proteins in the pathogenesis of these lesions. Two such proteins, tenascin and beta 6 integrin, are generally overexpressed in squamous carcinomas, and may play a central role in the invasive process of floor of the mouth lesions. The purpose of this study was to evaluate in situ and invasive squamous cell carcinomas from the floor of the mouth for the expression of tenascin and beta 6 integrin. Twenty lesions each of floor of the mouth in situ carcinomas and squamous cell carcinomas, and 10 normal controls were stained for tenascin and beta 6 using a standard immunohistochemical protocol for formalin-fixed specimens. Sections were assessed for staining intensity, pattern, and co-localization. Tenascin was highly expressed at the keratinocyte-connective tissue interface of both in situ and invasive carcinomas. beta 6 was expressed in basal keratinocytes of all in situ and invasive lesions, but was not evident in any of the control epithelia. There was no significant difference in staining of in situ and invasive carcinomas, but there was a significant difference in staining between these lesions and controls. Staining was colocalized in serial sections, supporting a receptor-ligand relationship. Both tenascin and beta 6 were weakly expressed in dysplastic areas adjacent to carcinomas suggesting that changes in the expression of these proteins occurs prior to the invasive phenotype. We conclude that tenascin and beta 6 are overexpressed in in situ and invasive floor of the mouth carcinomas, but that transgression of the basement membrane by neoplastic epithelial cells requires additional changes to the keratinocyte molecular profile.

Brachytherapy for T1-T2 floor-of-the-mouth cancers: the Gustave-Roussy Institute experience

PURPOSE

In a retrospective analysis, we evaluated the Gustave-Roussy Institute's experience of locoregional control, survival, and complications of low-dose rate brachytherapy for carcinoma of the floor of the mouth.

METHODS AND MATERIALS

Between 1970 and 1985, 160 patients with previously untreated carcinoma of the floor of the mouth received interstitial brachytherapy as definitive treatment. Of the 160 patients, 79 (49%) had T1 and 81 (51%) had T2 lesions, and 127 (79%) had N0 and 33 (21%) had N1; 84% of tumors arose from the anterior floor of the mouth. Brachytherapy was performed with 192Ir wires, according to the Paris system rules, followed by neck dissection (T2 or N1) or follow-up (T1N0).

RESULTS

With a follow-up period of 9-19 years, the observed survival rates were 89% at 2 years and 76% at 5 years, and the local control rates were 93% in T1 and 88% in T2 tumors. A low rate of distant metastases was noticed (5%); 31% of patients developed a second primary cancer. Severe mucosal necrosis was observed in <10% of patients. Any grade of bone necrosis was seen in 18% of cases (only 2.5% had G3 necrosis). This complication occurred more frequently in patients with poor dental status and in those treated without dental protection during implantation (p <0.001).

CONCLUSION

Radical brachytherapy offers excellent local control (89%) and an acceptable rate of complications (<10% severe necrosis) that may be significantly decreased with dental care and the use of protective devices. The high incidence of second malignancies remains a major concern in these patients.

pRb2/p130 protein expression is correlated with clinicopathologic findings in patients with oral squamous cell carcinoma

BACKGROUND

pRb2/p130 is one of the retinoblastoma (Rb) gene family and a suppressor oncogene. Immunohistochemically, the expression of pRb2/p130 was reported to be correlated inversely with the degree of malignancy in lung carcinoma and endometrial carcinoma. In the current study, the correlation between expression of pRb2/p130 and clinicopathologic factors in oral squamous cell carcinoma was investigated.

METHODS

One hundred twenty-two specimens from patients with oral squamous cell carcinoma were investigated by staining with a polyclonal antibody against pRb2/p130. The correlation between the expression of pRb2/p130 and various clinicopathologic factors was studied.

RESULTS

Positive staining for pRb2/p130 was observed in 61 of 122 cases (50.0%). pRb2/p130 expression was found to be correlated significantly with clinical stage (P = 0.050), cervical lymph node metastasis (P = 0.035), and tumor differentiation (P = 0.050). In the entire group a significantly reduced 5-year cumulative survival rate was observed in patients with pRb2/p130-negative tumors compared with patients whose tumors positively expressed pRb2/p130 (P = 0.0004). When tested with Cox proportional hazards regression analysis, the most significant independent prognostic factor for the entire group of 122 patients was found to be pRb2/p130 expression.

CONCLUSIONS

Expression of pRb2/p130 may be a good prognostic indicator in patients with oral squamous cell carcinoma and also may be utilized for the subclassification of tumors with the Grade 3 mode of carcinoma invasion.

Surgical treatment of early oral carcinoma-results of a prospective controlled multicenter study

PURPOSE OF THE STUDY

To assess whether early stage (pT1-2,pN0-1) oral cavity carcinoma is adequately treated by radical surgical resection alone.

MATERIAL AND METHODS

Prospective multicenter study. Of 105 patients with cT1-2 cN0-1 oral carcinoma treated in conformity with the study design, 12 had to be excluded because of tumor-positive margins or pN stage > N1. The remaining 93 patients were monitored for at least 2 years.

RESULTS

Seventeen patients had local or regional recurrence develop. In 12 of the 17 patients locoregional control was achieved by second treatment. Overall, the 4-year disease-specific survival probability was 94%. Patients treated initially without selective neck dissection had significantly higher recurrence rates than those with neck dissection, although the survival probability was not adversely affected.

CONCLUSIONS

Early (pT1-2, pN0-1) squamous cell carcinoma of the oral cavity is adequately treated by surgery alone, provided the resection margins are tumor free. On the basis of the presented data, we would also advocate routine selective neck dissection.

Prognostic value of graph theory-based tissue architecture analysis in carcinomas of the tongue

Several studies on oral squamous cell carcinomas (OSCC) suggest that the clinical value of traditional histologic grading is limited both by poor reproducibility and by low prognostic impact. However, the prognostic potential of a strictly quantitative and highly reproducible assessment of the tissue architecture in OSCC has not been evaluated. Using image analysis, in 193 cases of T1-2 (Stage I-II) OSCC we retrospectively investigated the prognostic impact of two graph theory-derived structural features: the average Delaunay Edge Length (DEL_av) and the average homogeneity of the Ulam Tree (ELH_av). Both structural features were derived from subgraphs of the Voronoi Diagram. The geometric centers of the cell nuclei were computed, generating a two-dimensional swarm of point-like seeds from which graphs could be constructed. The impact on survival of the computed values of ELH_av and DEL_av was estimated by the method of Kaplan and Meier, with relapse-free survival and overall survival as end-points. The prognostic values of DEL_av and ELH_av as computed for the invasive front, the superficial part of the carcinoma, the total carcinoma, and the normal-appearing oral mucosa were compared. For DEL_av, significant prognostic information was found in the invasive front (p < 0.001). No significant prognostic information was found in superficial part of the carcinoma (p = 0.34), in the carcinoma as a whole (p = 0.35), or in the normal-appearing mucosa (p = 0.27). For ELH_av, significant prognostic information was found in the invasive front (p = 0.01) and, surprisingly, in putatively normal mucosa (p = 0.03). No significant prognostic information was found in superficial parts of the carcinoma (p = 0.34) or in the total carcinoma (p = 0.11). In conclusion, strictly quantitative assessment of tissue architecture in the invasive front of OSCC yields highly prognostic information.

Analysis of treatment results for floor-of-mouth cancer

OBJECTIVE

This study reports the results of treating floor-of-mouth cancer with five different treatment modalities with long-term follow-up.

STUDY DESIGN

Retrospective study of 280 patients with floor-of-mouth cancer treated in the Department of Otolaryngology-Head and Neck Surgery at Washington University Medical School (St. Louis, MO) from 1960 to 1994.

METHODS

Patients with biopsy-proven squamous cell carcinoma of the floor of mouth who were previously untreated were treated with curative intent by one of five modalities and were all eligible for 5-year follow-up. The treatment modalities included local resection alone, composite resection alone (with neck dissection), radiation therapy alone, local resection with radiation therapy, and composite resection with radiation therapy. Multiple diagnostic, treatment, and follow-up parameters were studied using standard statistical analysis to determine statistical significance.

RESULTS

The overall 5-year disease-specific survival (DSS) was 56% with death due to tumor in 44% of patients. The 5-year cumulative disease-specific survival (CDSS) was 0.61 (Kaplan-Meier probability) with a mean of 8.3 years and a median of 9.7 years. The DSS by treatment modality included local resection (76%), composite resection (63%), radiation therapy (43%), local resection with radiation therapy (61%), and composite resection with radiation therapy (55%). Overall, there was no significant difference in DSS by treatment modality. Recurrence at the primary site (41%) was the most common site of treatment failure. Nineteen percent of patients had recurrence in the neck. Eighty-eight percent of initial recurrences occurred within 60 months after the onset of treatment. Metastasis to a distant site occurred in 30% of patients. Twenty percent of these patients had second primary cancers, and 53% of these patients died of their second primary cancers.

CONCLUSIONS

Significantly improved 5-year DSS was seen in the patients with clear margins, early clinical tumor stage, and negative nodes. Significantly decreased 5-year survival was seen in the patients with involved margins, advanced clinical tumor stage, positive nodes, and tumor recurrence. Patients with no clinically positive nodes (cNO) can be observed safely for regional nodal disease and subsequent positive nodes can be treated as they occur with no adverse affect on survival. Because of high recurrence rates at the primary site and neck, and an increased rate of both distant metastasis and the development of second primary cancers, patients should be monitored closely for a minimum of at least 5 years.

Postoperative brachytherapy alone for T1-2 N0 squamous cell carcinomas of the oral tongue and floor of mouth with close or positive margins

PURPOSE

To evaluate the efficacy of postoperative brachytherapy alone (brachy) for Stage T1-2 squamous cell carcinomas (SCC) of the floor of mouth (FM) and the oral tongue (OT) with close or positive margins.

METHODS AND MATERIALS

Between 1979 and 1993, 36 patients with T1-2 N0 (24 T1, 12 T2) OT (19), and FOM (17) SCC with close or positive margins following surgery underwent postoperative brachy. Mean patient age was 56 years (range 37-81) and sex ratio was 3.5:1 male:female. Mean surgery to brachy interval was 36 days (range 16-68). The technique used was interstitial Iridium-192 ((192)Ir) brachytherapy with plastic tubes and manual afterloading. Mean total dose was 60 Gy (range 50-67.4) at a mean dose rate of 0.64 Gy/h (range 0.32-0.94). Mean patient follow-up was 80 months.

RESULTS

The 5-year actuarial overall and cause-specific survivals of the entire group were 75% and 85%, respectively. The local control was 88.5% at 2 years, with a plateau apparent after 23 months. Of the 4 local relapses, 2 were salvaged with surgery and external beam radiotherapy (EBR). No tumor or treatment factors, including tumor size, margin status, disease site, or radiation dose, were correlated with local control. The 2 head and neck second primaries underwent curative treatment on nonirradiated tissue. One patient developed a grade 3 sequelae (bone and soft tissue necrosis). Grade 2-3 chronic sequelae were seen in 7 of 17 and 3 of 19 FOM and OT tumors, respectively (p = 0.09).

CONCLUSION

Postoperative brachy is a promising approach in T1-2 N0 OT and FOM SCC with close or positive margins. This approach is associated with high rate of locoregional control and low risk of chronic sequelae, obviates major surgery, avoids potential sequelae of EBR (xerostomia, dysgueusia, fibrosis), and avoids treatment of second head and neck primary on nonirradiated tissues.

Factors affecting survival for floor-of-mouth carcinoma

OBJECTIVES

The treatment of extensive floor-of-mouth carcinoma has remained a challenging problem for head and neck surgeons. We have reviewed our experience in the surgical management of floor-of-mouth cancer in an attempt to identify factors influencing survival.

METHODS

A total of 144 patients with cancer involving the floor of the mouth were treated between March 1988 and November 1995. A retrospective chart review was conducted that captured information including clinical staging, therapeutic modalities, pathologic findings, and patient follow-up. Factors affecting survival were assessed by nonparametric analysis and analysis of variance.

RESULTS

There was no statistical significance for the effects of vascular invasion (P = 0.4019), lymphatic invasion (P = 0.3430), bone invasion (P = 0.1548), or positive margins (P = 0.1113) on survival. Extranodal extension and recurrent disease were strongly suggestive of influencing survival but were not statistically significant (P = 0.0650 and P = 0.0504, respectively). Nodal disease significantly affected survival (P = 0.0138) but did not affect recurrence (P = 0.451).

CONCLUSION

Mean survival for this cohort was 30.6 months. Positive node status significantly affected mean overall survival in this series, whereas extracapsular disease did not. These data suggest that aggressive surgical management of neck disease is mandated to maximize survival.

Immunoperoxidase detection of polycyclic aromatic hydrocarbon-DNA adducts in mouth floor and buccal mucosa cells of smokers and nonsmokers

Tobacco smoking is a major risk factor for oral cancer; mouth floor and buccal mucosa are among the most and least cancer-prone subsites, respectively, in the oral cavity. We investigated the applicability of immunohistochemistry of smoking-induced DNA adducts in oral cells for assessing the exposure to carcinogens, and estimating the risk for oral cancer. Polycyclic aromatic hydrocarbon (PAH)-DNA adducts were measured in mouth floor and buccal mucosa cells of smokers (n = 26) and nonsmokers (n = 22) by means of a semiquantitative immunoperoxidase assay. Smokers had elevated levels of PAH-DNA adducts compared to nonsmokers in their mouth floor cells (0.045 +/- 0.022 versus 0.022 +/- 0.016, P = 0.0008 arbitrary units of immunohistochemistry) as well as in their buccal mucosa cells (0.058 +/- 0.028 versus 0.028 +/- 0.012, P = 0.001). Also, there was a correlation between the levels of PAH-DNA adducts in mouth floor cells and those in buccal mucosa cells (r = 0.4, P = 0.01). Furthermore, PAH-DNA adduct levels in both mouth floor and buccal mucosa cells were significantly related to current smoking indices (amount of tar and number of cigarettes consumed per day). Expectedly, the levels of PAH-DNA adducts neither in mouth floor cells nor in buccal mucosa cells, both being short-lived cells, were related to smoking history index (pack years). The levels of PAH-DNA adducts, however, in mouth floor cells as the cancer prone cells were lower than those in buccal mucosa cells (0.037 +/- 0.023 versus 0.044 +/- 0.026, P = 0.04). We conclude that immunohistochemistry of PAH-DNA adducts in oral cells can be used for exposure assessment of tobacco-related carcinogens, however, it cannot be used for oral cancer risk estimation.

Surgical management of head and neck cancer

Head and neck cancer surgery continues to evolve through the years and undergo improvement and refinement. In this article, the current state of head and neck cancer surgery is summarized in a site-by-site basis. The most important developments include organ-sparing surgery and microvascular free-tissue transfer for reconstruction.

Surgical management of the neck in squamous cell carcinoma of the floor of the mouth

Nodal involvement in squamous cell carcinoma considerably lowers survival rate. Despite its importance, neck management has still not been adequately explored. The Authors have retrospectively reviewed the records of 112 cases. Unilateral N+ were treated with a homolateral therapeutic and a controlateral prophylactic neck dissection; bilateral N+ were treated with a bilateral therapeutic neck dissection. On first observation the majority of cases (66.1%) were T1-2, N+ patients accounted for 45.5%. Among N- patients, 21.3% of occult nodal metastases were observed. The 5-year survival rate was 52.7%. With N+ lesions, a radical neck dissection should be performed; the dissection should be performed bilaterally. With N- lesions a prophylactic modified radical neck dissection is recommended in T2-4 lesions.

High dose rate versus low dose rate interstitial radiotherapy for carcinoma of the floor of mouth

PURPOSE

Patients with cancer of the floor of mouth are treated with radiation because of functional and cosmetic reasons. We evaluate the treatment results of high dose rate (HDR) and low dose rate (LDR) interstitial radiation for cancer of the floor of mouth.

METHODS AND MATERIALS

From January 1980 through March 1996, 41 patients with cancer of the floor of mouth were treated with LDR interstitial radiation using 198Au grains, and from April 1992 through March 1996 16 patients with HDR interstitial radiation. There were 26 T1 tumors, 30 T2 tumors, and 1 T3 tumor. For 21 patients treated with interstitial radiation alone, a total radiation dose of interstitial therapy was 60 Gy/10 fractions/6-7 days in HDR and 85 Gy within 1 week in LDR. For 36 patients treated with a combination therapy, a total dose of 30 to 40 Gy of external radiation and a total dose of 48 Gy/8 fractions/5-6 days in HDR or 65 Gy within 1 week in LDR were delivered.

RESULTS

Two- and 5-year local control rates of patients treated with HDR interstitial radiation were 94% and 94%, and those with LDR were 75% and 69%, respectively. Local control rate of patients treated with HDR brachytherapy was slightly higher than that with 198Au grains (p = 0.113). For late complication, bone exposure or ulcer occurred in 6 of 16 (38%) patients treated with HDR and 13 of 41 (32%) patients treated with LDR.

CONCLUSION

HDR fractionated interstitial brachytherapy can be an alternative to LDR brachytherapy for cancer of the floor of mouth and eliminate radiation exposure for the medical staff.