Malignant tumors of major salivary gland origin. A matched-pair analysis of the role of combined surgery and postoperative radiotherapy

Carcinoma of the major salivary glands. analysis of the role of radiation therapy

Forty-six patients of major salivary gland tumors were retrospectively studied. There were 40 (87%) parotid and 6 (13%) sub-mandibular tumors. Patients receiving adjuvant radiation therapy after a radical surgery fared much better (86%) complete response (CR) as compared to those treated for recurrent or inoperable disease (50% CR). The 5-year overall and disease free survival rates for the entire group is 70% and 34% respectively. These findings and a review of literature suggests that adjuvant post operative radition therapy is recommended to reduce the risk of post surgical recurrence.

Surgery of the salivary glands

Surgery of the salivary glands evolved rapidly after a greater understanding of the anatomy and pathologic processes affecting them was achieved. This article reviews the general and neurovascular anatomy of the major salivary glands. Understanding the anatomy of the salivary glands is a cornerstone of competent salivary gland surgery. The surgical techniques, potential pitfalls of surgery, and avoidance of postsurgical complications have been highlighted. Recent advances in surgical techniques are also presented.

Risk factors for local recurrence of adenoid cystic carcinoma: the role of postoperative radiation therapy

PURPOSE

Postoperative radiation therapy is often advocated in the treatment of patients with adenoid cystic carcinoma (ACC) of the head and neck. A retrospective analysis was performed to determine prognostic factors for local recurrence after surgery and to examine the role of postoperative radiation therapy.

MATERIALS AND METHODS

A retrospective analysis of 58 patients undergoing surgery for ACC of the head and neck at the University of Pittsburgh Medical Center from 1974 to 1994 was performed. Patients were followed up for a minimum of 24 months for the development of recurrent disease. The association of recurrence was correlated with clinical factors (age, sex, site, and stage); postoperative treatment (radiation therapy v no radiation); and pathologic variables (grade, margins of resection, and perineural invasion), and appropriate statistical analysis was performed.

RESULTS

Recurrent disease developed in 59% of patients, despite the addition of postoperative radiation therapy in 83% of patients. Tumor site was the single most important factor for the development of locally recurrent disease and was correlated with primary tumor stage and resection margins. Local recurrence rates were decreased (P = .07) in patients with negative surgical margins who were irradiated.

CONCLUSIONS

Larger perspective randomized trials are necessary to evaluate the efficacy of postoperative radiation, and new treatments need to be investigated to improve local control rates for ACC of the head and neck.

National Cancer Data Base report on cancer of the head and neck: acinic cell carcinoma

BACKGROUND

Management of acinic cell carcinoma is based on reports of small numbers of cases accrued over several decades.

METHODS

The National Cancer Data Base (NCDB) identified 1353 cases of acinic cell carcinoma of the head and neck for the years 1985 to 1995. Chi square analyses of selected contingency tables and Wilcoxon regression analyses of selected survival stratifications are presented.

RESULTS

Five-year survival was 83.3% (observed) and 91.4% (disease specific). Worse survival was associated with high grade (p < .0001), age greater or equal to 30 years (p = .0055), and the presence of metastatic disease (p < .0001).

CONCLUSIONS

An aggressive subset of acinic cell carcinoma which is characterized by high grade and advanced stage rarely occurs in patients younger than 30 years old. Although better outcome was not statistically demonstrated for combined therapy, surgery with irradiation is the most common management in the United States for cases with regional metastases, high grade, and microscopic positive margins.

Facial nerve rehabilitation after radical parotidectomy

OBJECTIVE

Examine functional outcomes in patients undergoing radical parotidectomy and facial nerve grafting. Identify factors that may affect rehabilitation in these patients.

STUDY DESIGN

Retrospective chart review and photographic analyses of 12 patients undergoing radical parotidectomy with interposition nerve grafts for facial nerve reconstruction.

METHODS

Data obtained for each patient regarding age, sex, histology of parotid neoplasm, cable graft source, administration of postoperative radiotherapy, and treatment for eye rehabilitation. Functional outcomes were assessed with the House-Brackmann grading system at 6 months, 1 year, and 2 years after surgery.

RESULTS

All nerve grafts were harvested from cervical plexus sensory nerves with microscopic epineural repair performed for all neurorrhaphies. Overall, 9 of 12 patients achieved a grade III 2 years after surgery. All patients under age 30 obtained a grade III. Of the seven patients receiving postoperative radiation, five achieved a grade III. Older patients often required surgical procedures to facilitate eye closure.

CONCLUSIONS

Facial nerve rehabilitation after radical parotidectomy can be successfully achieved with cervical plexus interposition nerve grafts. Postoperative radiotherapy did not appear to affect return of function, and younger patients consistently achieved good functional outcomes after nerve grafting. Older patients frequently require surgical procedures for eye rehabilitation after radical parotidectomy.

Clinico-pathological and treatment-related factors influencing survival in parotid cancer

One hundred and three patients with primary parotid cancer treated surgically at the Christie Hospital, Manchester (1952-1992), were analysed to assess the influence on survival of prognostic and treatment-related factors. Thirty-seven patients were treated by surgery alone (SG), 66 received post-operative radiation (SG+RT). Median follow-up was 12 years, minimum 5 years. The 10-year disease-specific survival rates for stage I, II and III/IV were 96%, 61% and 17% respectively (P < 0.0001). The various histological types segregated into three survival patterns: low-, intermediate-and high-grade with 10-year survival rates of 93%, 41% and 50% respectively (P < 0.0001). On multivariate analysis, the factors influencing risk of cancer death in order of importance were: tumour size > 4 cm (P < 0.001), presence of nodes (P = 0.001), histology of adenoid cystic carcinoma (P = 0.01), high-tumour grade (P = 0.02) and perineural involvement (P = 0.01). Neither the extent of surgery nor the operator influenced outcome. Overall, adjuvant RT significantly reduced locoregional recurrence (SG+RT 15% vs SG 43%; P = 0.002) but not survival, although on subanalysis, there was a trend to improved survival with large cancers and high-grade tumours. Long-term survival is determined primarily by tumour characteristics, namely clinical stage and grade. Post-operative RT contributes significantly to locoregional control and probably confers some survival advantage in high-risk patients.

Neutron radiotherapy for the treatment of locally advanced major salivary gland tumors

BACKGROUND

Malignant salivary gland tumors are rare tumors of the head and neck region. The treatment of these tumors has generally consisted of surgical extirpation, with postoperative radiotherapy improving locoregional control and survival in patients with high risk tumors. Neutron radiotherapy has been found to be more efficacious than conventional radiotherapy in the setting of inoperable or subtotally resected salivary gland tumors.

METHODS

One hundred forty-eight patients with malignant salivary tumors of major salivary gland origin were treated at the University of Washington Medical Center with fast neutron radiotherapy between the years 1984 and 1995. One hundred twenty-eight patients were treated with curative intent, and of these, 120 patients had evidence of gross residual disease at the time of treatment. These patients constitute the main analysis of this paper. Of these patients, 19% had recurrent disease, 39% were initially seen with positive lymph nodes, and 11% had previously received full dose conventional radiotherapy. At the time of analysis, the median period at risk of survivors was 26 months.

RESULTS

The 5-year actuarial locoregional control rate for all patients with gross tumor treated with curative intent was 59%. A tumor size < or =4 cm was associated with an excellent locoregional control rate (80%), and cause-specific survival (73%) at 5 years compared with patients with larger tumors (35% and 22%, respectively, p<.001 in both cases). On univariate analysis, there appeared to be an advantage in locoregional control for patients with smaller sized tumors (< or =4 cm) who underwent an attempted surgical extirpation. Locoregional control was excellent (100%) in patients having a complete surgical resection of their tumors and undergoing postoperative neutron radiotherapy because of the presence of other high risk factors. Lymph node status at the time of treatment, base of skull involvement, and male sex were associated with the development of distant metastasis, with 52% of node positive patients developing distant metastases by 5 years, compared with 32% of node negative patients (p = .04).

CONCLUSIONS

Neutron radiotherapy is an effective form of treatment for patients with high risk, locally advanced tumors of major salivary gland origin. An initial surgical resection appears beneficial in patients for whom such an approach is feasible.

Neck dissection in the treatment of cancer of major salivary glands

The treatment of the neck nodes in salivary gland tumors has changed considerably in the last two decades. The current thinking and the rationale for it are discussed in detail in this article.

Salivary duct carcinoma ex pleomorphic adenoma: analysis of the findings in fine-needle aspiration cytology and histology

Salivary duct carcinoma (SDC) is an uncommon and highly aggressive neoplasm that reveals histopathologic features resembling infiltrating duct carcinoma of the breast and prostate. SDC arising on the basis of preexisting pleomorphic adenoma (PA) is very rare. This report describes the fine-needle aspiration (FNA) cytology of a case of SDC ex PA. FNA smears were cellular with cells with large, pleomorphic nuclei, some prominent nucleoli, and finely vacuolated cytoplasm. The neoplastic cells were forming groups, sheets, and papillary structures and a cribriform pattern was present in some sheets. Mitotic figures were frequently seen. Necrosis was prominent in the background. Histologic sections of the tumor revealed areas of comedo carcinoma, papillary carcinoma, and infiltrative carcinoma as well as multiple foci of PA. The presence of a cribriform pattern, tumor cells resembling breast ductal carcinoma cells, and a necrotic background are helpful features for an accurate cytodiagnosis of SDC.

Neutron therapy in malignant salivary gland tumors: results at European centers

Malignant salivary gland tumors are relatively rare and account for only 3%-4% of all head and neck cancers. Especially in adenoid cystic carcinoma, the incidence of local recurrence and distant metastases is influenced by the perineural spread of tumor. In advanced salivary gland tumors, surgery alone has a high incidence of local failure. The results of conventional radiotherapy are suboptimal in inoperable or not completely resected salivary gland tumors and in recurrent disease. The pooled data of some international series for low linear energy transfer radiation show a local control of only 28%. Especially in advanced salivary gland tumors, neutron therapy can improve local control. In Europe at least 570 patients with salivary gland tumors have been treated with neutrons alone or with combined modalities. The clinical data of different centers in Europe and the United States result in a similar local control rate of 67% in gross disease. An analysis of different European series shows on average a complication rate of 10.6% for severe radiation-related morbidity. Modern neutron machines and the use of three-dimensional treatment planning systems are now available in a few institutions and may further reduce side effects.

Postoperative radiotherapy for malignant tumors of the parotid gland

PURPOSE

To update our experience using postoperative irradiation in selected patients with carcinomas of the parotid gland. Outcomes of treatment with a focus on the effectiveness of the two primary techniques of radiation used for treating these tumors were evaluated.

METHODS AND MATERIALS

A retrospective analysis of 166 patients with parotid gland malignancies treated in the Department of Radiotherapy at the University of Texas M. D. Anderson Cancer Center between 1965-1989 was performed. All patients were treated following surgery and did not have macroscopic disease at the time of their radiation. The most common histologies were mucoepidermoid carcinoma (28%) and adenocarcinoma (27%). Pathologic features constituting indications for postoperative radiotherapy included: inadequate margins, 104 (63%) cases; extraglandular disease extension, 82 (49%); perineural invasion 57 (34%); and nodal disease 43 (26%). Radiation was delivered through an ipsilateral field of predominantly high energy electrons in 142 patients (86%). Wedged paired 60Co fields were used to treat 19 patients. The median dose was 60 Gy, typically delivered at 2 Gy per fraction. The median follow-up time for surviving patients was 155 months.

RESULTS

Forty-seven (29%) patients had disease recurrence, of whom 15 (9%) had disease recur locally and 10 (6%) regionally (neck). There was no association between the dose of radiation and local failure, except for a trend for patients with positive margins and/or named nerve involvement to have improved local control if they received doses > 60 Gy. There was no difference in failure rates in patients treated with wedged pair techniques or ipsilateral fields, but there was a higher complication rate in the former. Overall, 37 patients (22%) developed chronic sequelae attributed to radiation. Twelve patients developed decreased hearing, and 15 patients developed soft tissue or bone necrosis or exposure.

CONCLUSIONS

Local and regional control rates for high risk patients with parotid gland carcinomas treated with radiation following surgery were excellent. The technique of using an ipsilateral field encompassing the parotid bed and treated with high energy electrons often mixed with photons was effective with minimal severe late toxicity. The moderate complication rate experienced in this series can be further reduced using modern techniques as described.

Long-term follow-up of over 1000 patients with salivary gland tumours treated in a single centre

Between 1947 and 1992, 1403 patients with 1432 salivary gland tumours were treated at the Christie Hospital, Manchester. There were 1194 epithelial neoplasms: parotid, 1082 (91 per cent); submandibular, 47 (4 per cent); minor glands, 65 (5 per cent). The commonest histological diagnoses were pleomorphic adenoma (n = 776) and adenolymphoma (n = 159). A total of 244 carcinomas were seen (adenoid cystic carcinoma, n = 75). Treatment was primarily surgical, conservative where possible, and determined by tumour extent and not histology. Adjuvant radiation therapy was used in over half the definitively treated malignancies. The recurrence rate following the treatment of 551 new parotid pleomorphic adenomas was 1.6 per cent at median follow-up 12.5 (range 1-34) years, increasing to 15 per cent in the secondarily referred group (n = 170). For patients with definitively treated primary salivary carcinomas (n = 148), the disease-free survival rate at 5, 10 and 15 years was 58, 47 and 45 per cent respectively. Using multivariate analysis, clinical stage was the most important predictor of survival; the 10-year survival rate for stages I-IV was 96, 70, 47 and 19 per cent respectively.

European results in neutron therapy of malignant salivary gland tumors

In Europe to date, 501 patients with salivary gland tumors have been treated with neutrons alone or with combined modalities. The most common histological types are adenoid cystic carcinomas, mucoepidermoid carcinomas and malignant mixed tumors. The results of conventional radiotherapy are suboptimal in inoperable or incompletely resected salivary gland tumors and in recurrent disease. The pooled data of some international series for low linear energy transfer radiation show a local control of 28%. Especially in advanced tumors neutron therapy can improve local control and should be the treatment of choice. The clinical data from different therapy centers in Europe show local control of 67% in gross disease.

Treating tumors of the sublingual glands, including a useful technique for repair of the floor of the mouth after resection

BACKGROUND

From a 55-year experience with about 4,000 patients treated for salivary gland tumors, we have identified 18 patients (0.5%) who received definitive treatment for neoplasms arising in the sublingual glands.

PATIENTS AND METHODS

Patient ages ranged from 35 to 76 years (median 59), and men and women were equally represented. All had malignant tumors, which included adenoid cystic carcinoma (9 patients), mucoepidermoid carcinoma (5 patients), and adenocarcinoma (4 patients). An asymptomatic swelling was the most common complaint (7 patients); the tumor was incidentally discovered by a dentist in 4 others. For all patients, the treatment delay ranged from 3 to 24 months, but only 3 had lesions that extended beyond the confines of the floor of the mouth. All were treated surgically by resections, which were peroral in 4 patients, transcervical in 5, and pull-through type (including the submandibular gland) in 7. The remaining 2 patients had composite procedures. In 3 more recently treated patients, pull-through resections were followed by a floor-of-the-mouth repair involving transmandibular sutures. This technique has proved useful and will be described in detail.

RESULTS

Results in this small patient cohort have been most encouraging. Local recurrence occurred in 3 patients who succumbed 11 months, 27 months, and 21 years after initial treatment. Fourteen others remain alive and well 20 months to 20 years (median 74 months) posttreatment, and the remaining patient was recurrence free when he died of unrelated causes 7 years after resection.

CONCLUSION

This small experience confirms the rarity of sublingual gland tumors and attests to the good results in terms of function and survival that can be anticipated with adequate surgical treatment when the lesion is relatively small.

Changing trends in the management of salivary tumors

Fine-needle aspiration biopsy (FNAB) and computed tomography (CT) or magnetic resonance imaging (MRI) are useful in the evaluation of salivary gland tumors, but they are not essential for treatment planning in every patient. The mainstay of therapy is a well-planned and carefully executed surgical procedure which adequately excises the tumor. Disease-free survival is very likely in patients with early stage malignant tumors. When treatment is delayed until the tumor is extensive (Stage 3,4), local recurrence and distant metastases are common and survival rates are low. Adjunctive postoperative radiation therapy can enhance locoregional control in the latter patients, but does not invariably lead to better survival. No consistently effective chemotherapy agents or combinations are presently available. Early diagnosis and consistent, high quality treatment offer the best hope for improved survival.

Radiotherapy for parotid cancer

BACKGROUND

Parotid malignancies represent a heterogeneous group of tumors primarily managed by surgical extirpation. Moderately high recurrence rates are seen after surgery alone, and postoperative radiotherapy has been used for patients with higher risks for local failure.

METHODS

To assess the role of radiotherapy in the management of patients with malignant tumors of the parotid gland, the records of 68 patients receiving megavoltage therapy at our institution from 1966 to 1989 were reviewed. Patients were placed into three groups for analyses. Group I was composed of 41 patients receiving radiotherapy following total gross removal of parotid cancer by surgical procedures, varying from excisional biopsy through total parotidectomy. Radiation dose for this group ranged from 4,995 to 6,500 cGy. Group II was composed of 10 patients treated with radiotherapy after incisional biopsy or excision with positive margins. These patients received radiation doses of 4,000-9,470 cGy. Group III was composed of 17 patients receiving radiotherapy for a postsurgical local recurrence. Their radiation dose ranged from 4,300 to 8,400 cGy.

RESULTS

Two of the 41 patients from group I developed a local recurrence. Two of these patients also developed distant metastases, one concurrent. Two of 10 group II patients failed locally, whereas three developed distant metastases. Only nine of the 17 patients in group III were controlled locally, and four patients developed distant dissemination.

CONCLUSION

Total gross excision of parotid cancer, sparing facial nerve if possible and followed by regional radiotherapy, provides excellent rates of local control and survival with modest toxicity. Patients presenting postoperatively with gross residual tumor or recurrence after surgery should be considered for trials of more aggressive treatment with combined chemotherapy or altered fractionation schemes of irradiation.

Parotid Cancer: Treatment and Results

The records of 74 consecutive patients with primary parotid malignancy were reviewed. The age and sex incidence was comparable to that described in previous studies; we observed a high incidence of adenocarcinoma not reported by other investigators. Stage at the time of examination and histologic grade of tumor were independent statistically significant predictors of clinical outcome. Long survival with low grade disease and late recurrence were common. Radiation therapy has been shown to increase survival in a number of studies; however, it had no demonstrable benefit in our series. Parotid cancer should be managed aggressively and early surgery is indicated for all parotid neoplasms. Neck dissection is indicated for clinically positive nodes and high grade cancers; radiation therapy is indicated for high grade cancers and residual disease.

Salivary duct carcinoma: a report of nine cases

Nine cases of salivary duct carcinoma are presented. Eight lesions were located in the parotid gland and one in the submandibular gland. Tumor size was greater than 3 cm in four cases (44%), and facial paralysis was observed in five tumors (62.5%). Lymph node metastases were observed macroscopically or microscopically in seven patients. Perineural and lymphatic invasion were detected in eight and seven cases, respectively. Free surgical margins were obtained in eight of the nine patients (88%). Adjuvant postoperative irradiation was delivered in eight patients. Five patients died of disease in spite of the different clinicopathologic characteristics and aggressiveness of the surgery and irradiation. None of the parameters studied correlated with the final outcome.

Stage means more than grade in adenoid cystic carcinoma

Our experience with 184 previously untreated patients who had adenoid cystic carcinoma of salivary gland origin is reviewed. Retrospective staging was possible in all but nine patients who had minor salivary gland primary tumors. Sixty-three percent of patients were diagnosed as having stage I or stage II disease (stage I, 64 patients; stage II, 47 patients), whereas 43 and 21 patients had stage III and IV tumors, respectively. Grading was as follows: cribriform pattern only (grade 1, 126 patients; 68%), mixed cribriform and solid features (grade 2, 48 patients; 26%), and solid only (grade 3, 10 patients; 5%). Treatment was predominantly surgical (174 patients), and relatively few patients received adjunctive, postoperative irradiation (27 patients). Cumulative 10-year survival was 75%, 43%, and 15% for stage I, stage II, and stage III and IV patients, respectively, and cause-specific survival at 10 years was as high as 94% in patients with stage I disease. Only the clinical stage had a significant impact on survival. Neither survival, regional metastases (16 patients; 11%), nor distant dissemination (64 patients; 43%) was predictable on the basis of tumor grade alone. The prognosis in patients with early stage lesions may be better than has been appreciated.

The role of fast neutron radiation therapy in the management of advanced salivary gland malignant neoplasms

Fifty-three patients with locally advanced salivary gland malignant neoplasm were treated with fast neutron radiation therapy. All patients received treatment for gross inoperable, residual unresectable, or recurrent disease--clinical situations in which results using photon irradiation were suboptimal. With a median follow-up of 42 months and a minimum follow-up of 1 year, locoregional tumor control in the treatment field was achieved in 92% (48 of 52) of patients. An additional eight patients had regional failures outside the treatment field, resulting in an overall locoregional tumor control rate of 77% (40 of 52). The 5-year actuarial locoregional control rates were 65% overall and 75% in patients with node-positive disease. Grouping patients according to prior treatment status, actuarial 5-year locoregional control rates were 92% for patients treated definitively (without a prior surgical procedure), 63% for those treated postoperatively for gross residual disease, and 51% for those treated for recurrent disease after a surgical procedure. The P values associated with these differences were 0.12 and 0.01, respectively. There were no instances of radiation-induced facial nerve damage. This study suggests that neutron irradiation alone should be the therapy of choice in the treatment of advanced-stage salivary gland tumors and that surgery should be limited to those patients in whom disease-free margins can be obtained. The potential morbidity of a debulking surgical procedure before neutron irradiation is not warranted by an improvement in loco-regional control over that achievable with neutron therapy alone.

The indications for elective treatment of the neck in cancer of the major salivary glands

To define the indications for elective neck treatment, the cases of 474 previously untreated patients were reviewed who had locally confined major salivary gland cancers treated between 1939 and 1982. Clinically positive nodes were present in 14% (67 of 474). Overall, clinically occult, pathologically positive nodes occurred in 12% (47 of 407). By univariate analysis, several factors appeared to predict the risk of occult metastases; however, multivariate analysis revealed that only size and grade were significant risk factors. Tumors 4 cm or more in size had a 20% (32 of 164) risk of occult metastases compared with a 4% (nine of 220) risk for smaller tumors (P less than 0.00001). High-grade tumors (regardless of histologic type) had a 49% (29 of 59) risk of occult metastases compared with a 7% (15 of 221) risk for intermediate-grade or low-grade tumors (P less than 0.00001). In view of the low frequency of occult metastases in the entire group, routine elective treatment of the neck is not recommended. High-grade tumors and larger tumors have a high rate of occult neck metastases, and treatment should be considered in this group.

Malignant epithelial tumors in the minor salivary glands, the submandibular gland, and the sublingual gland. Prognostic factors and treatment results

Ninety-five malignant tumors in the submandibular gland, the sublingual gland, and the minor salivary glands seen in a 25-year period were reviewed. The patients were retrospectively staged using the Union Internationale Contre le Cancer (UICC) classification. The most frequent tumor was adenoid cystic carcinoma, followed by adenocarcinoma. The submandibular gland was the most frequent location. Five-year and 10-year crude survival rates were 62% and 43%, respectively. Clinical stage was the most important prognostic factor. Survival was not correlated with location of tumor, although recurrence and metastases occurred more frequently in patients with cancer of the submandibular gland. Histologically, the 5-year and 10-year survival was significantly better for patients with adenoid cystic carcinoma compared with the other types; however, although still significant, this difference diminished at 10 years, confirming the need for a long observation time for patients with this tumor.

The importance of clinical staging of minor salivary gland carcinoma

We reviewed a 45-year experience with 459 patients who had previously untreated minor salivary gland neoplasms, 378 (82%) of which were malignant. Data were adequate for retrospective clinical staging in 353 of the 378 patients with malignant tumors using criteria identical to those for squamous carcinoma in the same sites. Five-, 10-, and 15-year survival rates for the patients with malignant tumors treated after 1966 were 75%, 62%, and 56%, respectively, a significant improvement compared with results reported previously. Multivariate analysis confirms that survival was significantly influenced by the clinical stage and the histologic grade, but the applicability of grading was limited to patients with mucoepidermoid carcinoma or adenocarcinoma. Ten-year overall survival was 83%, 53%, 35%, and 24% for patients with stage I through stage IV, respectively. Results in these patients are similar to those we have recently reported in patients with major salivary gland carcinomas, but we are unable to demonstrate that postoperative radiotherapy improved survival.

Diagnosis and pitfalls in the treatment of parotid tumors

Any swelling near the ear is best considered a parotid neoplasm until proved otherwise. The diagnosis is primarily based on the clinical examination. Imaging studies are best reserved for patients who present with palate or tonsil swellings, which must be distinguished from parapharyngeal or minor salivary gland tumors. Almost all benign, and most malignant parotid tumors can be resected with preservation of the facial nerve. Aspiration biopsy can add useful information, but is not essential for treatment planning as the extent of the surgical procedure is primarily determined by the extent of the tumor. Survival rates in patients with malignant tumors are most significantly influenced by tumor stage. Results seem to have improved in recent years, possibly because we are treating a larger proportion with favorable lesions. Another factor may relate to the enhancement of locoregional control now achieved with postoperative radiotherapy, particularly in patients with Stage III or IV tumors.

Postoperative radiation therapy for major salivary gland malignancies

Between 1966 and 1982 there have been 46 patients treated with surgery plus post-operative radiation therapy for malignant tumors of salivary gland origin. The indication(s) for radiotherapy included positive margins (42%), advanced local tumor (37%), positive nodes (33%), or high grade histology (48%). Overall actuarial local control at 5 years was 73%, being 100% for T1, 83% for T2, 80% for T3, and 43% for T4. Actuarial survival at 5 years was 80% for T1, 83% for T2, 60% for T3, and 48% for T4. Patients with positive nodes (N+) did worse than those with negative nodes (No), with locoregional control and survival at 5 years being 58% vs. 83%, (P = 0.025) and 38% vs. 80% (P = less than .01), respectively. We found no need for contralateral neck treatment even for those with positive nodes. Also, to date, none of eight patients with adenoid cystic histology has failed locally, as opposed to three of eight failures in patients treated with surgery alone. We believe that post-operative irradiation provides excellent locoregional control for appropriate patients with malignant tumors of major salivary glands.