An analysis of radiotherapy in the management of 104 patients with parotid carcinoma

Radiotherapy for cutaneous head and neck cancer and parotid tumours: a prospective investigation of treatment-related acute swallowing and toxicity patterns

PURPOSE

Reports of acute treatment-related dysphagia and toxicities for patients with parotid tumours or cutaneous head and neck cancer (HNC) are limited. This study aimed to describe the severity and timing of dysphagia and related toxicities experienced during radiotherapy for cutaneous HNC and parotid tumours, to inform the nature of future speech pathology (SP) service models required during treatment.

METHODS

Prospective study of 32 patients with parotid tumours and 36 with cutaneous HNC undergoing curative non-surgical management. Dysphagia and acute toxicity data was collected weekly during treatment and at 2, 4 and 12 weeks post-treatment using the Functional Oral Intake Scale, diet descriptors and CTCAE v4.0.

RESULTS

In both groups, minimal treatment toxicities (grades 0-1) were observed. Xerostomia and dysgeusia were the most frequently reported grade 2 toxicities. Only 3% of parotid patients and 6% with cutaneous HNC experienced grade 3 dysphagia. Full or soft texture diets were maintained by > 70% of patients in both groups. Symptoms peaked in the final week of treatment and rapidly improved thereafter. Apart from xerostomia < 10% of patients had any grade 2 toxicity at 12 weeks post-treatment.

CONCLUSION

Patients in these subgroups of HNC experienced minimal treatment-related toxicity during radiotherapy. As such, the need for supportive symptom management by SP is low. Models that involve interdisciplinary surveillance of symptoms with referral to SP only when required may be best suited for these individuals to ensure issues are identified whilst minimising patient burden created by unnecessary routine SP appointments.

Surgery and Radiotherapy in the Treatment of Malignant Parotid Tumors: A Retrospective Multicenter Study

Aims and background

Major salivary gland cancers are rare, with many histologic types and subtypes. The low incidence and heterogeneity of primary parotid carcinomas makes their outcome difficult to evaluate. Treatment remains primarily surgical, but optimal therapeutic regimens have yet to be fully realized. The present study reviews the experience of three Italian institutions in the treatment of primary parotid carcinomas in order to describe the clinicopathological presentation and treatment options with emphasis on radiotherapy and to analyze the factors influencing survival.

Methods and study design

The records of 110 patients with primary parotid neoplastic lesions treated at three Italian institutions from 1993 to 2004 were retrospectively reviewed. Six patients were excluded from the study: 3 received surgery alone and 3 were not assessable, for a total of 104 assessable patients. Acute and late toxicity of radiotherapy was quantified following the recommendations of the RTOG/EORTC. Survival was analyzed by the actuarial Kaplan-Meier product-limit method. The influence of selected factors on 10-year disease-specific survival was analyzed.

Results

The 104 assessable patients were treated as follows: 11 patients received radiotherapy as their only treatment (3 with a palliative purpose) and 93 had postoperative radiotherapy. Thirty-two patients underwent neck dissection: neck lymph node metastases were found in all them. Their mean age was 60 years (range, 14–92). According to the UICC/2002 TNM Classification, 8 patients were stage I, 19 stage II, 34 stage III, 25 stage IVA, 5 stage IVB, 3 recurrent and 10 not assessable (Tx). The most frequent histologies were adenoid cystic carcinoma (n = 16), mucoepidermoid carcinoma (n = 15), and acinic cell carcinoma (n = 15). Twenty-three patients had recurrences: 10 had local recurrences, 3 neck recurrences, 9 distant metastases, and 1 patient had both local recurrence and distant metastases. No factors were observed that would negatively influence the prognosis. Actuarial 10-year disease-specific survival was 71% and actuarial 10-year local control 82%.

Conclusions

The treatment of salivary gland malignancies remains primarily surgical. Our study confirms the results of the literature with surgery and adjunctive radiotherapy in patients with advanced-stage disease. No variables were observed to influence the prognosis.

[Radiotherapy of carcinoma of the salivary glands]

Indication, doses, and technique of radiotherapy for salivary glands carcinoma are presented, and the contribution of neutrons and carbon ions. The recommendations for delineation of the target volumes and organs at risk are detailed.

Les tumeurs des glandes salivaires

Tumors of salivary glands arise mainly from the parotid gland. Magnetic Resonance Imaging (MRI) is mandatory not only to localize precisely the tumor within the gland but also to differentiate between benign and malignant neoplasms, in competition with cytology in fine-needle aspiration biopsy. Tumors without risk of transformation, such as adenolymphoma, are not systematically operated on. Indications of roentgenotherapy and irradiation volumes depend on histologic type, localisation and size of the tumor.

Carcinoma of the hard palate treated with radiotherapy: a retrospective review of 31 cases

There are few studies reporting the results of radical radiotherapy for carcinoma of the hard palate. We have examined our results of patients treated within a single institution, and assessed survival, local control and morbidity. A retrospective analysis was made on 31 patients with hard palate carcinoma treated with external beam radiotherapy at the Christie Hospital between 1990 and 1997. Twenty-six patients received radiotherapy alone and five were treated for post-operative positive surgical margins. The 5-year actuarial survival rate was 55%. The actuarial 5-year local control rate was 53%, rising up to 69% after salvage surgery. Survival was 48% for squamous cell carcinomas and 63% for salivary gland carcinomas, the difference was not significant. The only significant predictor of local control was T-stage, with 80% 5-year local control of T1-2 lesions and 24% control of T3-4 lesions. N-stage was the only significant factor predicting for survival. Radiation necrosis occurred in one patient. Radical radiotherapy for carcinoma of the hard palate is safe and well tolerated. It is an effective treatment for both squamous cell carcinoma and salivary gland carcinoma.

Optimisation of radiotherapy for carcinoma of the parotid gland: a comparison of conventional, three-dimensional conformal, and intensity-modulated techniques

BACKGROUND AND PURPOSE

To compare external beam radiotherapy techniques for parotid gland tumours using conventional radiotherapy (RT), three-dimensional conformal radiotherapy (3DCRT), and intensity-modulated radiotherapy (IMRT). To optimise the IMRT techniques, and to produce an IMRT class solution.

MATERIALS AND METHODS

The planning target volume (PTV), contra-lateral parotid gland, oral cavity, brain-stem, brain and cochlea were outlined on CT planning scans of six patients with parotid gland tumours. Optimised conventional RT and 3DCRT plans were created and compared with inverse-planned IMRT dose distributions using dose-volume histograms. The aim was to reduce the radiation dose to organs at risk and improve the PTV dose distribution. A beam-direction optimisation algorithm was used to improve the dose distribution of the IMRT plans, and a class solution for parotid gland IMRT was investigated.

RESULTS

3DCRT plans produced an equivalent PTV irradiation and reduced the dose to the cochlea, oral cavity, brain, and other normal tissues compared with conventional RT. IMRT further reduced the radiation dose to the cochlea and oral cavity compared with 3DCRT. For nine- and seven-field IMRT techniques, there was an increase in low-dose radiation to non-target tissue and the contra-lateral parotid gland. IMRT plans produced using three to five optimised intensity-modulated beam directions maintained the advantages of the more complex IMRT plans, and reduced the contra-lateral parotid gland dose to acceptable levels. Three- and four-field non-coplanar beam arrangements increased the volume of brain irradiated, and increased PTV dose inhomogeneity. A four-field class solution consisting of paired ipsilateral coplanar anterior and posterior oblique beams (15, 45, 145 and 170 degrees from the anterior plane) was developed which maintained the benefits without the complexity of individual patient optimisation.

CONCLUSIONS

For patients with parotid gland tumours, reduction in the radiation dose to critical normal tissues was demonstrated with 3DCRT compared with conventional RT. IMRT produced a further reduction in the dose to the cochlea and oral cavity. With nine and seven fields, the dose to the contra-lateral parotid gland was increased, but this was avoided by optimisation of the beam directions. The benefits of IMRT were maintained with three or four fields when the beam angles were optimised, but were also achieved using a four-field class solution. Clinical trials are required to confirm the clinical benefits of these improved dose distributions.

Beam-orientation optimization of intensity-modulated radiotherapy: clinical application to parotid gland tumours

BACKGROUND AND PURPOSE

An optimization algorithm has been developed to determine the best beam-arrangement for a small number of intensity-modulated radiotherapy (IMRT) fields. The algorithm is designed to avoid, if possible, beam-orientations that pass through organs-at-risk (OARs) with low radiation tolerance.

MATERIALS AND METHODS

An independent, fast IMRT algorithm based on the Bortfeld algorithm was developed to determine the profile of the intensity-modulated beams (IMBs) for each beam-arrangement and a fast-simulated-annealing algorithm finds the 'optimal' beam-arrangement. The final beam-arrangement was transferred to the CORVUS (NOMOS Corporation) treatment planning system, and the IMBs were re-optimized for comparison with a standard nine-field, equi-spaced arrangement. The algorithm has been initially tested on a single example patient, with a parotid gland carcinoma.

RESULTS

The nine-field, IMRT plan for an example patient with a parotid gland tumour significantly reduced the dose to the cochlea compared with the conformal radiotherapy plan. In addition, the planning-target-volume (PTV) homogeneity was improved, but the plan produced a higher dose to the contralateral parotid (73% of the OAR received more than 6 Gy). The beam-orientation optimization algorithm produced a three-field plan that greatly reduced the dose to the contralateral parotid (maximum dose of 2 Gy), whilst maintaining the PTV dose homogeneity and the reduced cochlear dose of the nine-field plan. Some changes in the dose to the other OARs, namely the brain and the oral cavity, were seen, but were deemed not to be clinically significant.

CONCLUSIONS

In conclusion, IMB-orientation optimization for head and neck treatment sites can produce improvements in treatment plans with only a few fields.

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.

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.