Cancer of retromolar trigone: long-term radiation therapy outcome

Clinical characteristics and prognosis of patients with primary squamous cell carcinoma of the retromolar trigone: A SEER-based analysis

BACKGROUND

Primary squamous cell carcinoma of the retromolar trigone (primary SCC RMT) is an uncommon malignant tumor. There is still much to learn about its clinicopathological characteristics and prognosis. In order to better understand the clinicopathological features and predictive survival aspects of primary SCC RMT, this study examined data from the SEER database from 2000 to 2020. Furthermore, in order to forecast the overall survival (OS) and cancer-specific survival (CSS) of patients with primary SCC RMT, we created nomograms.

METHOD

The Surveillance, Epidemiology and End Results (SEER) database was used to retrieve the information on individuals with primary SCC RMT who received a diagnosis between 2000 and 2020. Both univariate and multivariate analyses were conducted using the Cox proportional risk regression model. Using R software, prognostic nomograms were created to forecast the OS and CSS likelihood. The nomograms' prediction abilities were evaluated using the consistency index (C-index), calibration curve, and receiver operating characteristic (ROC) curve.

RESULT

A total of 1717 patients with primary SCC RMT were included, they were randomly assigned to the primary and validation cohorts in a 7:3 ratio using R software. Multivariate Cox regression revealed that age, marital status, regional nodes positive, Summary stage, TNM stage, T stage, N stage, surgery were independent prognostic factors of OS, and age, marital status, regional nodes positive, tumor sizes, Summary stage, N stage, surgery were independent prognostic factors of CSS in the primary cohort. The C-index of the nomogram OS was 0.705 (95 % CI: 0.685-0.725) and the C-index of CSS was 0.734 (95 % CI:0.714-0.754) in the primary cohort. In validation cohort, the C-index of the nomogram OS and CSS were 0.730 (95 % CI: 0.710-0.750) and 0.723 (95 % CI: 0.684-0.762), respectively. The 1-, 3-, and 5-year OS and CSS rates in the primary cohort and validation cohort were approximately in line with the nomogram estimations, in accordance to the calibration curves.

CONCLUSION

We conducted an analysis using the SEER database to investigate the features, survival outcomes, and prognostic parameters of patients with primary SCC RMT. And we developed two prognostic nomograms that can be used by clinicians to forecast the 1-, 3-, and 5-year overall survival and cancer-specific survival of patients with primary SCC RMT.

Retromolar trigone squamous cell carcinoma: A population-based analysis of survival

OBJECTIVES

To evaluate the difference in overall survival (OS) in patients with retromolar trigone squamous cell carcinoma (RMT SCC) treated with surgery alone versus surgery plus postoperative radiotherapy (PORT) versus surgery plus postoperative chemoradiotherapy (POCRT).

MATERIALS AND METHODS

Retrospective cohort study of patients from 1,500 US facilities reporting to the National Cancer Database (NCDB) registry. Participants were adult patients treated with surgery as primary treatment modality for RMT SCC (n = 2,877). Exposures were primary definitive surgery versus surgery + PORT versus surgery + POCRT. Outcomes included OS after diagnosis and treatment of RMT SCC. A multivariate Cox proportional hazards model was constructed to compare survival between the three treatment modalities. Subgroup analysis was performed by T classification and overall staging.

RESULTS

There were 1,415 (50%) patients treated with surgery alone, 870 (30%) patients treated with surgery + PORT, and 572 (20%) treated with surgery + POCRT. Treatment with surgery + PORT was associated with improved OS compared to surgery alone (relative hazard: 1.25, 95% CI: 1.01, 1.54, p = 0.042). Patients treated with surgery + POCRT also had improved OS compared with surgery alone (relative hazard: 1.89, 95% CI 1.45, 2.43, p < 0.001). Patients with T3/4 tumors had improved OS when treated with surgery + PORT (relative hazard 1.39, 95% CI: 1.05, 1.84, p = 0.022) or surgery + POCRT (relative hazard 2.27, 95% CI: 1.66, 3.15, p < 0.001). Patients with T1 or T2 disease had no significant difference in survival in both the surgery + PORT (p = 0.331) and surgery + POCRT treatment groups (p = 0.134). Therefore, there was no difference in OS for patients with stage I or II disease treated with surgery + PORT (p = 0.451), nor with surgery + POCRT (p = 0.853).

CONCLUSION

Treatment with surgery + PORT +/- chemotherapy appears to be associated with significantly improved OS compared to surgery alone for advanced RMT SCCa.

A systematic review of therapeutic outcomes following treatment of squamous cell carcinoma of the retromolar trigone

Squamous cell carcinoma (SCC) of the retromolar trigone (RMT) is a rare but potentially fatal disease that carries a poor prognosis due to its unique anatomic position. RMT SCCs tend to spread to vital nearby structures, including the tonsillar pillar, masticatory muscles, and underlying mandibular bone, even in their early stages, and aggressive treatment is often warranted. This systematic review appraises and qualitatively analyzes all available literature regarding the survival outcomes and prognosis of RMT SCC. Four databases were searched to identify all eligible articles published since January 1980. Of the 1,248 studies, a total of 15 studies representing 4,838 cases met the inclusion criteria. The evaluated patients had a high rate of advanced tumor stage (T3 or T4: 61.4%), lymph node metastasis (38.8%), and mandibular bone invasion (24%) at the time of diagnosis. Aggressive surgical treatments such as lip-splitting (92%), segmental mandibulectomy (61.1%), radical neck dissection (44.1%), and reconstruction using free flaps (49.5%) was undertaken for 92% of the pooled patient population. The mean rates for local, regional, and systemic recurrence were 23.40%, 8.40%, and 8.50%, respectively. The mean 5-year overall survival rate was 38.90%. Osteonecrosis was noted in 11.6% of the 328 patients who received radiotherapy. In conclusion, RMT SCC is generally associated with high recurrence, low survival, and high postoperative complication rates. Early diagnosis and aggressive treatment are thus warranted. However, significant methodological problems hamper current knowledge. Future studies of this topic that use randomized or cohort designs are thus needed.

Treatment outcomes of patients with primary squamous cell carcinoma of the retromolar trigone

OBJECTIVES/HYPOTHESIS

Squamous cell carcinoma of the retromolar trigone (RMT SCC) is a relatively uncommon primary site for oral cavity malignancy. However, given its proximity to the mandible and buccal mucosa, RMT SCC typically exhibits early invasion and generally presents at an advanced stage. Large-sample studies are needed to assess the epidemiology and clinical outcomes of this tumor. Our aim was to describe the determinants of survival in patients with RMT SCC.

STUDY DESIGN

Retrospective cohort study.

METHODS

Retrospective, population-based cohort study of patients in the Surveillance, Epidemiology, and End Results tumor registry who were diagnosed with RMT SCC from 1973 to 2012. Primary endpoints were overall survival (OS) and disease-specific survival (DSS).

RESULTS

A total of 4,022 cases of RMT SCC were identified. The mean age at diagnosis was 65 years. Thirty-nine percent of cases presented with stage IV disease. The median OS by stages I to IV were 73.7, 52.4, 27.5, and 23.4 months, respectively (P < .05). Overall, 34.3% of patients underwent surgery, 23.5% received radiation therapy, and 34.1% had both surgical and radiation therapy. On multivariate analysis, advanced age, greater tumor size, and advanced stage were associated with worse OS and DSS (P < .05), surgery predicted improved OS and DSS (P < .05), and radiation therapy predicted improved OS only (P < .05).

CONCLUSIONS

RMT SCC is an aggressive malignancy that portends a poor prognosis, though early-stage tumors (stages I and II) have significantly improved survival. Any surgical intervention independently predicted higher survival outcomes. There may be a role of dual modality approaches, particularly for larger tumors.

LEVEL OF EVIDENCE

4 Laryngoscope, 128:2740-2744, 2018.

Complete remission of rare adenocarcinoma of the oropharynx with APCEDEN® (dendritic cell-based vaccine): a case report

APCEDEN^® is an autologous monocyte‐derived dendritic cell‐based immunotherapy. A 58‐year‐old man with adenocarcinoma of oropharynx shows complete remission after receiving APCEDEN^® in conjunction with Geftinib validated by reduction in size, whereas Gefitinib alone lead to disease progression.

Squamous cell carcinoma of the retromolar trigone: Treatment outcomes

OBJECTIVE

Squamous cell carcinoma (SCC) of the retromolar trigone is uncommon, accounting for 1.4% of all oral cancer cases in Japan. Few studies have examined the optimal treatment for this cancer. The aim of this study was to evaluate the outcome of treatment for primary SCC of the retromolar area.

METHODS

We retrospectively analyzed the outcome and prognosis of 45 patients (38 men, 7 women) with SCC of the retromolar trigone who underwent treatment in our department between July 1992 and March 2011.

RESULTS

Mean age was 62.4 years. Clinical stages were: stage I (n=4, 8.9%); stage II (n=10, 22.2%); stage III (n=5, 11.1%); and stage IVa (n=26, 57.8%). Surgical resection was performed in all patients and 6 patients also received postoperative radiotherapy. Reconstructive surgery using free flaps was performed in 38 patients; postoperative complications occurred in 5 of these patients. The 3-year local control rate was 80%, and the 3-year over all survival rates for stage I, II, III, and IV disease were 100%, 80%, 40%, and 49.2%, respectively. Cause of death was the original disease in 23 cases and other diseases in 2 cases. The most common cause of death from the original disease was cervical lymph node metastasis.

CONCLUSION

The presence of cervical lymph node metastasis was a negative prognostic factor. Marginal mandibulectomy may be selected for patients without distinct bone-marrow infiltration.

Treatment Outcomes of Rare Retromolar Trigone Squamous Cell Carcinoma Using Combined Modalities

Background

Retromolar trigone squamous cell carcinoma is relatively uncommon and due to its complex anatomy has always remained a challenge in terms of loco-regional control and survival. Surgery, radiotherapy, and chemotherapy as combined modalities have been used but high recurrence rates result in poor outcome.

Methods

We have retrospectively evaluated records of 62 patients treated in Head and Neck Oncology unit of Shaukat Khanum Memorial Cancer Hospital and Research Centre (SKMCH and RC), Lahore, Pakistan from 2004 to 2014 who were included based on the criteria of histopathological proven squamous cell carcinoma of retromolar trigone (RMT) treated with radical intent. Diagnostic workup for all patients involved clinical examination, imaging modalities usually magnetic resonance imaging (MRI), computerized tomography (CT), Orthopantomogram (OPG), and chest x-ray (CXR) to evaluate regional and distant metastasis, respectively. Kaplan-Meier survival curves were used to depict survival.

Results

The study was comprised of 36 male and 26 female patients. Treatment modalities used are surgery only (n = 1), radiotherapy alone (n = 13), radiotherapy followed by surgery (n = 10), chemoradiotherapy (n = 16), induction chemotherapy followed by concurrent chemoradiotherapy (n = 19), induction chemotherapy followed by surgery, and radiotherapy (n = 2). Surgical interventions include wide local excisions (n = 6), marginal mandibulectomy (n = 4), and segmental mandibulectomy (n = 4). Surgical margins were clear in 54%, close in 38%, and involved in 8% of patients. AJCC 7th edition showed cT1 8%, cT2 22%, cT3 14%, and cT4 56% while pT1 2%, pT2 3%, and pT4 8%. During follow-up, 18% patients have come up with local recurrence, 22% showed persistent disease while 9% have presented with distant metastasis. The five-year and overall survivals are 38% and 22%, respectively.

Conclusion

Retromolar trigone involvement poses many vital structures at risk of involvement. Late presentation results in involvement of masticator space compromising both mouth opening and surgical outcomes. Surgery and radiotherapy have shown comparable results in disease control. Bone invasion has shown poor outcome in terms of loco-regional control and overall survival.

Retromolar trigone squamous cell carcinoma treated with radiotherapy alone or combined with surgery: a 10-year update

PURPOSE/OBJECTIVES

Treatment outcomes were analyzed for patients who received radiotherapy for squamous cell carcinoma of the retromolar trigone at a single institution.

MATERIALS/METHODS

We reviewed the medical records of 110 patients treated with radiotherapy alone (n=36) or radiotherapy combined with surgical resection of the primary tumor (n=74) between June 1966 and October 2013. The median follow-up was 4.5years for all patients and 11.8years for living patients (range, 1.3-23.5years).

RESULTS

The 5-year local-regional control rates after definitive radiotherapy versus surgery and radiotherapy for stages I-III were 52% and 89% and for stage IV they were 46% and 58%, respectively. The 5-year cause-specific survival rates after definitive radiotherapy compared with surgery and radiotherapy for stages I-III were 57% and 82% and for stage IV they were 45% and 43%, respectively. Multivariate analyses revealed that the likelihood of cure was better with surgery and radiotherapy compared with radiotherapy alone (p=0.041).

CONCLUSION

Patients treated with surgery and radiotherapy had a better chance of cure than those treated with radiotherapy alone. Complications of treatment were common in both groups but more common in patients who underwent surgery.

Surgical errors and risks - the head and neck cancer patient

Head and neck surgery is one of the basic principles of head and neck cancer therapy. Surgical errors and malpractice can have fatal consequences for the treated patients. It can lead to functional impairment and has impact in future chances for disease related survival. There are many risks for head and neck surgeons that can cause errors and malpractice.

To avoid surgical mistakes, thorough preoperative management of patients is mandatory. As there are ensuring operability, cautious evaluation of preoperative diagnostics and operative planning. Moreover knowledge of anatomical structures of the head and neck, of the medical studies and data as well as qualification in modern surgical techniques and the surgeons ability for critical self assessment are basic and important prerequisites for head and neck surgeons in order to make out risks and to prevent from mistakes. Additionally it is important to have profound knowledge in nutrition management of cancer patients, wound healing and to realize and to be able to deal with complications, when they occur.

Despite all precaution and surgical care, errors and mistakes cannot always be avoided. For that it is important to be able to deal with mistakes and to establish an appropriate and clear communication and management for such events. The manuscript comments on recognition and prevention of risks and mistakes in the preoperative, operative and postoperative phase of head and neck cancer surgery.

Dynamic contrast-enhanced MR perfusion imaging of head and neck tumors at 3 Tesla

BACKGROUND

Dynamic contrast-enhanced (DCE) MR perfusion imaging allows assessment of vascular density and integrity of tumors. The purpose of this study was to determine the diagnostic efficacy of time intensity curve analysis on DCE MRI for characterization of head and neck tumors.

METHODS

Twenty patients underwent T1-weighted fast field echo DCE MRI with temporal resolution of 2.6 seconds. In total, 100 dynamic phases covering 20 slices were obtained in 4.5 minutes. Time to peak (TTP), relative maximum enhancement (RME) ratio, and relative washout ratio (RWO) were calculated.

RESULTS

Malignant tumors had a significantly lower RME (p = .025) and prolonged TTP with lower RWO than benign lesions. Postradiation changes had a significantly longer TTP (p = .024) and lower RWO (p = .007) than did postradiation recurrent tumors. Receiver operating characteristic (ROC) analysis revealed RWO had highest accuracy (area under the curve [AUC] = 1.0).

CONCLUSIONS

DCE MR perfusion imaging provides pivotal information regarding microcirculation, potentially improves differentiation of malignant tumor from postradiation changes.

The treatment of oral cancer: an overview for dental professionals

Oral cancer is a serious life-threatening disease. Dental professionals may be the first individuals to identify/suspect these lesions before referring to oral and maxillofacial surgeons and oral medicine specialists. Because the general dentist will likely follow on with the patient's future oral health, it is important that he or she has a basic understanding of the various treatments involved in treating oral malignancies and their respective outcomes. The four main modalities discussed in this review include surgery alone, radiotherapy alone, surgery with radiotherapy, and chemotherapy with or without surgery and radiotherapy. Chemotherapy has become an area of great interest with the introduction of new 'targeted therapies' demonstrating promising results in conjunction with surgery. Despite these results, the toxicities associated with chemotherapy regimens are frequent and can be severe, and therefore may not be suitable for all patients. Treatment modalities have improved significantly over the decades with overall decreases in recurrence rates, improved disease-free and overall survival, and an improved quality of life. Prognosis, however, is still ultimately dependent on the clinical stage of the tumour at the initial diagnosis with respect to size, depth, extent, and metastasis as recurrence rates and survival rates plummet with disease progression.

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.

The effect of surgical resection in the region of the retromolar trigone

Tumours in the mucosa of the retromolar trigone (RMT) are rare, but develop insidiously and spread rapidly into surrounding structures. Resection may require radical dissection beginning usually on the medial side of the mandible. Such surgery can put important structures at risk. The normal anatomy of the RMT and its relations has been studied together with simulated surgical incisions and resections. Tissue removed was processed by histological techniques in order to demonstrate structures excised or damaged by the operation. The simulated incision showed that the lingual nerve, submandibular duct and palatoglossus were at particular risk. This could affect sensation, speech, swallowing and movements of the tongue. The findings pose immediate concerns for surgeons operating in this area. Although cancer surgery often involves sacrificing tissue, care should be taken to preserve structures vital to the patient's oral function without compromising oncological principles.

Dynamic contrast-enhanced magnetic resonance imaging in radiotherapeutic efficacy in the head and neck tumors

PURPOSE

The purpose to this study is to identify correlations between pathology and dynamic contrast-enhanced magnetic resonance imaging (MRI) and to assess the utility of this technique in the evaluation of radiation response for head and neck cancer.

MATERIALS AND METHODS

MRI was prospectively performed after radiotherapy in 27 patients with various head and neck tumors. After bolus injection of contrast material, a dynamic study was performed using a spoiled gradient-recalled imaging sequence. The maximum slope of increase (MSI) on the time-intensity curve was displayed as a color-coded image. The ratio of MSI (MSIR) was obtained for tumor and normal muscles. Pathological specimens were obtained after MRI in all cases. Histological grading of irradiation changes was classified into 5 grades (0-4). Correlations between MSIR and histological grade were examined.

RESULTS

Histologically, 18 tumors were classified as grade 2 (presence of viable tumor cells), 4 were grade 3 (nonviable tumor cells), and 5 were grade 4 (no tumor cells). Although the mean +/- SD of MSIR in patients with histological grade 2 or 3 was 7.4 +/- 7.9, MSIR in patients with grade 4 was 1.8 +/- 0.73, representing a significant difference ( P < .05). Every patient with grade 4 displayed an MSIR of 2.5 or less, although 5 of 22 patients with grade 2 or 3 had an MSIR of 2.5 or less.

CONCLUSIONS

MSI quantitatively reflects response to radiotherapy for head and neck cancer. Color-coded MSI display is feasible for depicting permeability changes after radiotherapy.

Retromolar trigone squamous cell carcinoma treated with radiotherapy alone or combined with surgery

BACKGROUND

Treatment outcomes were analyzed for retromolar trigone squamous cell carcinoma.

METHODS

Between June 1966 and August 2003, 99 patients were treated with radiotherapy alone (35 patients) or radiotherapy combined with surgery (64 patients). Followup ranged from 0.2 to 23.8 years (median, 3.3 yrs). All living patients had followup for at least 1 year.

RESULTS

The 5-year local-regional control rates after definitive radiotherapy versus surgery and radiotherapy were as follows: Stages I-III, 51% and 87%; Stage IV, 42% and 62%; and overall, 48% and 71%, respectively. The 5-year cause-specific survival rates after definitive radiotherapy compared with surgery and radiotherapy were as follows: Stages I-III, 56% and 83%; Stage IV, 50% and 61%; and overall, 52% and 69%, respectively. Multivariate analyses revealed that the likelihood of cure was better with surgery and radiotherapy compared with definitive radiotherapy.

CONCLUSIONS

The likelihood of cure after treatment for retromolar trigone squamous cell carcinoma was influenced by the extent of disease and treatment. Patients treated with surgery and radiotherapy had a better outcome than those treated with radiotherapy alone.

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.

FDG-PET scanning after radiation can predict tumor regrowth three months later

PURPOSE

Positron emission tomography (PET) with 2-[(18)F]fluoro-2-deoxy-D-glucose (FDG) is well known for providing excellent clinical information regarding malignant tumors. We investigated whether dual-time FDG-PET performed immediately post radiation could predict early regrowth of malignant tumors.

MATERIALS AND METHODS

Twenty patients with malignant tumors were included in this study. All patients received radiation, and each underwent FDG-PET before the initiation of therapy and within 10 days of completing their course of irradiation. PET images after irradiation were obtained at 60 min and 180 min post FDG injection. For 26 lesions in 20 patients, standardized uptake value (SUV) before and after treatment was calculated and then correlated with postradiation tumor response and outcome at 3 months status post irradiation.

RESULTS

Retention index [RI = (SUV on delayed image - SUV on early image)/SUV on early image] after irradiation showed a significant difference between patients with residual tumor and those without residual tumor at 3 months status post irradiation (p < 0.0025). All 9 lesions in 6 patients with residual tumors showed more than 0.1 of RI, whereas none of the lesions with less than 0.1 of RI revealed residual tumors.

CONCLUSIONS

Dual-time FDG-PET imaging just after irradiation is potentially useful for predicting early regrowth of malignant tumors.

Management of cancer of the retromolar trigone

Treatment of cancer of the retromolar trigone (RMT) is controversial. While early lesions may be managed with single-modality, more advanced lesions may invade the mandible, pterygoid musculature, and the adjacent mucosa of the tonsillar pillar and soft palate, therefore making therapeutic decisions more complicated. Treatment options traditionally include surgical resection, external beam irradiation, and combined modality therapy. The choice of therapy is dependent on the extent of the tumor, nodal metastasis, and the medical status of the patient and comorbid conditions. The following review outlines the current issues relevant to the diagnosis and therapy of patients with RMT malignancy.