The changing role of external-beam irradiation in the management of malignant tumors of the major salivary glands

Simultaneous pleomorphic adenoma of the left parotid gland and adenoid cystic carcinoma of the contralateral sublingual salivary gland: a case report

INTRODUCTION

Sublingual salivary gland neoplasms are extremely rare, accounting for only 0.3-1% of all epithelial salivary gland tumors. Most of the sublingual tumors are malignant, adenoid cystic carcinoma (ACC) and mucoepidermoid carcinoma (MEC) being the most common histological types. The coexistence of two salivary gland tumors located in different major salivary glands is uncommon.

CASE REPORT

A rare case of two simultaneous tumors of the major salivary glands, one in the sublingual and the other in the contralateral parotid gland in a female patient is reported.

DISCUSSION

The diagnostic procedure followed, and the management of the patient, is outlined in the paper.

Mucoepidermoid carcinoma of the salivary glands. Review of the literature and clinicopathological analysis of 18 patients

Salivary gland carcinomas are a rare and clinically diverse group of neoplasms among which mucoepidermoid carcinomas (MEC) are reported to be the most frequently encountered. During the years 1994-2004 18 patients with MEC were treated in our Department. All patients underwent surgery with a curative intent, and in 11 of them treatment was supplemented by radiotherapy. Follow up ranged from 6 to 120 months. Twelve (66.6%) MECs originated from the major salivary glands with the majority located in the parotid. Histologically, 50% of tumors were classified as low grade, 28% as intermediate and 22% as high-grade MECs. Positive surgical margins were documented in six cases (33%) and all in tumors of high or intermediate histological grade. All these patients received adjuvant radiotherapy and one developed local recurrence. Local recurrence occurred in two more patients with histologically free margins. Both received postoperative radiotherapy. Distant metastases were documented in four patients all between 14 and 24 months after surgical treatment. An association between local recurrence and distant metastasis might be suggested since all patients with local recurrences subsequently developed distant metastases. The 5-year overall disease specific survival rate was 85%. Statistical multivariate analysis demonstrated that the factor that significantly correlated with overall survival was the histological grade of tumors (Log Rank test: p=0.013). A trend towards poorer survival was observed in patients aged over 50 years. Our results also suggested a potential benefit of postoperative radiotherapy for patients with positive margins.

Paediatric mucoepidermoid carcinoma of the palate

The purpose of this paper is to review our experience with mucoepidermoid carcinoma (MEC), a rare tumour in minor salivary glands, in a small series of paediatric patients. A retrospective analysis of minor salivary gland tumours seen by one surgeon from March 1991 to December 1999 was undertaken. A total of 58 cases were identified and of these, five (9%) occurred in children. There were 23 cases of MEC, four (17%) of which occurred in patients under the age of 18 who presented with T1 or T2N0M0 low- to intermediate-grade MEC of the palate and adjacent structures. These patients form the basis of this study. All patients were treated with wide local excision, obtaining tumour-free margins, and followed for a mean number of 58 months. None of these tumours invaded bone and resection of bone was not performed in any case as the periosteum was intact and the tumours were low to intermediate grade. To date, all patients remain free of disease. One patient who went elsewhere for treatment, was treated with local resection only, and has also experienced no recurrence. Wide local excision is the treatment of choice for low to intermediate grade MEC of the minor salivary glands in paediatric patients.

Adenoid cystic carcinoma of the sublingual gland--an unusual presentation

A case of adenoid cystic carcinoma of the sublingual salivary gland presenting as recurrent submandibular salivary gland swelling is described. The obstructive symptoms were due to involvement of the ipsilateral submandibular duct by the tumour. A review of the literature suggests that this is the first such case to be reported. The importance of intra-oral examination when investigating swellings of the neck is emphasised.

The role of radiotherapy in the management of salivary gland carcinomas

A retrospective study was performed on 44 patients with carcinoma originating in the major and minor salivary glands to examine the effects of postoperative radiotherapy on locoregional and distant control and survival. 22 patients were treated by surgery alone and the 22 other patients were treated by a combination of surgery and postoperative irradiation. In the surgery group, local recurrence developed in all 8 patients with evidence of residual disease at the surgical margins, whereas local control was achieved in 7 of 15 patients with positive surgical margins in the combination group and the control rate was related to the amount of residual disease. Neck metastasis, which developed in 13 patients (30%), was not affected by the status of surgical margins or by the treatment modality. On the other hand, the incidence of distant metastasis seen in 19 patients (43%) was much higher in patients with positive surgical margins and the development of distant metastasis in these patients was not prevented by postoperative irradiation. The survival rates at 5, 10 and 15 years were 54, 48 and 41%, respectively, for the irradiated patients, whereas the values for the patients treated by surgery alone were 75, 70 and 70%, respectively. The results indicate that postoperative irradiation is effective in controlling local recurrence but not neck and distant metastases. Wide excision with sufficient surgical margins followed by postoperative radiotherapy and systemic chemotherapy are essential to obtain a better prognosis.

Radiotherapy in epithelial tumors of the parotid gland: case presentation and literature review

A group of 113 patients irradiated for parotid tumor was studied retrospectively. Sixty-two patients were irradiated after superficial parotidectomy or enucleation of a pleomorphic adenoma. None of them had a recurrence after 5-15 years. Sixteen patients were irradiated postoperatively after surgery for a recurrence of pleomorphic adenoma. Only one of them had developed a recurrent tumor. Thirty-five patients with a malignant parotid tumor were treated by irradiation, 22 after surgery and 13 after biopsy only. Patients with a low malignancy tumor (10/11) and adenoid cystic carcinoma (6/12) responded better than patients with a high malignancy carcinoma (2/12). A tumor larger than 4 cm, facial nerve palsy, lymph node metastasis, and inoperability indicate a poor prognosis. With high dose radiotherapy it is possible to treat inoperable tumors successfully. Adenoid cystic carcinomas can respond well to irradiation alone.

An approach to malignant parotid tumours

A series of 30 patients with malignant parotid tumours selected for surgical treatment is presented. There were 18 males and 12 females, with an age range of 12-80 years. All presented with a parotid lump, one had an associated painful facial nerve palsy and one had clinically involved neck nodes. Four had previous surgery, surgical biopsy or radiotherapy. Pre-operative fine needle aspiration was performed on one patient. Postoperative radiotherapy was administered to 14 patients. Follow-up was for a mean of 5.5 years. The primary tumour was controlled by surgery alone in 15 of the 16 patients. There was one local recurrence and two patients in this group died from distant metastases. Of the group receiving postoperative radiotherapy, there was one local recurrence, one local and neck recurrence and one death from distant metastases. Mobile, discrete tumours can be treated by parotidectomy with preservation of the facial nerve and the selective use of radiotherapy. The malignant tumour with restricted mobility but no facial palsy is treated by parotidectomy, sacrificing only involved branches and postoperative radiotherapy. The clinically fixed lesions with facial palsy demand total parotidectomy in operable cases, nerve sacrifice and postoperative radiotherapy.

Electron beam therapy in treatment of parotid neoplasm

In a retrospective analysis, 42 patients with malignant primary tumor of the parotid gland were evaluated considering survival, local recurrence and tolerance of treatment. All patients referred to radiotherapy were treated by electron beam (10-15 MeV) and followed for more than 5 years. Postoperative radiotherapy after radical operation, with no macroscopic disease, was performed in 18 patients, 7 of whom were treated by radical re-operation and radiation of a recurrent parotid neoplasm. In these groups, the local recurrence rate was 4/18 (22%) and 2/7 (29%), the 5-year survival rate was 9/18 (50%) and 5/7 (71%). In 17 patients, radiotherapy started with gross tumor left behind. This group showed a local recurrence rate of 10/17 (59%) and a 5-year survival of 7/17 (41%). Treatment was well tolerated with no major sequelae. Local tumor control and its impact on survival is discussed.

Salivary gland malignant neoplasms: treatment and prognosis

A retrospective analysis of 183 patients with malignant salivary gland tumors treated between 1955 and 1978 is presented. The analysis showed that radiation therapy lowered the recurrence rates after surgery and controlled approximately one-third of the inoperable tumors. A dose-response relationship exists and the data suggest that the radiation dose should not be less than that corresponding to a CRE-value of 1950 reu (70 Gy/7 weeks). Histology, location and clinical stage are important prognostic factors.

Adenoid cystic carcinoma of the major and minor salivary glands. A clinicopathological study of 17 cases

Local recurrence and distant metastasis were studied in relation to treatment modality and histological findings in 17 patients with adenoid cystic carcinoma of the major and minor salivary glands. Fifteen patients underwent surgical resection with or without postoperative irradiation and the others were treated by irradiation alone. Local recurrence developed in nine patients (52.9%), mostly within two years of the treatment. Incomplete removal was the major reason for the failure to control the primary lesion. Postoperative irradiation was of value in preventing recurrence in patients who demonstrated microscopic residual disease at the surgical margins, whereas it was not effective if gross residual tumour was recognized. Direct surgical intervention on the tumour tissue could have been the possible cause for the distant metastasis that developed in 10 (58.8%) of the 17 patients. Surgical excision with a wider safety margin than the visibly affected area, followed by postoperative irradiation and chemotherapy was essential to obtain a better prognosis.

Clinical evaluation of neutron beam therapy. Current results and prospects, 1983

Some 9000 patients throughout the world have been treated by some form of neutron beam therapy. These include patients with advanced nonresectable tumors in many different sites treated with a variety of neutron beam generators varying widely in beam energy. Protocols were largely nonrandomized and included both mixed beam studies (neutrons + photons) and neutrons alone in varying doses. In spite of wide variation in equipment, treatment technique, and philosophy, some consistent trends have been identified: (1) in general, the neutron results have been at least as good as those of the photon controls measured in terms of local control, although the incidence of significant side effects have been higher; (2) in none of the randomized studies conducted so far, largely comprising epidermoid carcinomas of the head and neck, has a clear survival advantage for neutrons over photon controls been demonstrated at a statistically significant level; (3) results with mixed beam studies have been uniformly equivocal, with marginally significant differences in favor of the experimental groups compared with the photon controls; (4) adenocarcinomas of the gastrointestinal tract (GI) tract, including tumors of the salivary gland, pancreas, stomach, and bowel, appear to be responsive to high linear energy transfer (LET) radiation; (5) nonepidermoid, radioresistant tumors (sarcoma of bone and soft tissue and melanoma) yield a consistantly high local control rate, with neutron irradiation strikingly superior to those reported with photon therapy; and (6) in the central nervous system, both normal tissues and tumors appear to be exceptionally sensitive to neutron irradiation, therapeutic ratios are small, and the prospect of cure remains remote. It is concluded that neutrons are efficacious for certain specific tumor types, but that essentially new study designs, based on nonrandomized matched case comparisons, will be required to prove the merit of the new modality.

Primary carcinoma of Stensen's duct: recognition and management with literature review

Primary carcinoma of Stensen's duct is a rare neoplasm with only 15 cases reported in the English literature since 1927. The authors present a recent additional patient and discuss their criteria for the determination of true primary ductal lesions based upon clinical presentation, operative findings, and tumor histology. This method of selection, most particularly involving electron microscopy in the reported case, is necessary to define whether the lesion originates from the ductal epithelium. All previously reported cases were reviewed, together with the actual pathologic slides in four available cases. Only ten were retained as primary ductal lesions. Most important, this analysis clarifies the natural history of these neoplasms and reinforces a recent theory of histogenesis of salivary gland tumors. In light of these findings, a rational treatment plan can be suggested.

Response of epidermoid and non-epidermoid cancers of the head and neck to fast neutron irradiation: the Fermilab experience

One hundred and six patients with locally advanced cancers of the head and neck were treated with neutrons at the Fermilab Neutron Therapy Facility. Of these, 44 patients were previously untreated, 33 were recurrent following attempted surgery and 29 patients had previously received a full course of radiation therapy with conventional radiation. Results were analyzed to study the influence of stage, previous management, site of origin and tumor histology on local control of the disease. The most significant factor determining the outcome in this series of patients is the histological type. For epidermoid carcinoma, long term local control was achieved in 17/35 patients (49%) in the previously unirradiated group. With non-epidermoid tumors (adenocarcinoma, cylindroma, muco-epidermoid carcinoma), the local control rate was 28/39 (72%). Disease-free survival analysis also shows a survival advantage in non-epidermoid lesions treated with neutrons. It is concluded that neutron beam therapy may probably be the treatment of choice for non-resectable or recurrent non-epidermoid cancers of the head and neck and requires a clinical trial to establish this observation.