Sarcomas of the Head and Neck

Overview
Overall, sarcomas are particularly rare neoplasms as they constitute only 1% of all cancer diagnosed in the United States and 1% of all head and neck primary cancers. Furthermore, these tumors do not commonly manifest as primary malignancies in the head and neck region except in the pediatric population, in which as many as 35% of all sarcomas affect head and neck sites. The most commonly encountered sarcomas of the head and neck region are osteogenic sarcoma, malignant fibrous histiocytoma, rhabdomyosarcoma, and angiosarcoma.

The rarity of sarcomas, as well as the multitude of histologic subtypes, can make definitive diagnosis difficult, and an experienced pathologist is key to the initial evaluation. Appropriate pathologic characterization forms the basis for prognosis and subsequent treatment selection. The biology of a neoplasm and its propensity for locally aggressive growth and systemic dissemination are clearly reflected in its histology and grade. Size and location of the lesion, which have become more precisely delineated with improvements in radiographic modalities, also impart reliable prognostic information. All of these factors, along with the complexities of head and neck anatomy (especially regarding function and cosmesis), make optimal treatment difficult to determine in many cases.

Traditionally, surgery has formed the cornerstone of therapy for head and neck sarcomas. However, multimodality treatment of these tumors incorporating a multidisciplinary approach has yielded encouraging results. Data collected by ongoing cooperative studies such as the Intergroup Rhabdomyosarcoma Study Group (IRSG) have demonstrated improved outcomes for those patients treated with surgery along with other nonsurgical modalities. These protocols also serve as a model for the evolving roles of chemotherapy and radiation either as adjuvant treatments or even primary therapy in select patients. As a result, many patients, particularly children, are now able to avoid surgery in functionally and cosmetically critical areas of the head and neck without compromising their survival.

Osteosarcoma
Osteogenic sarcoma is the most common nonhematopoietic malignant neoplasm of bone, usually occurring in the long bones of adolescent patients. However, 10% of these neoplasms arise in the head and neck region and occur in patients who are on average 10 to 15 years older than those patients with tumors occurring in other body sites. Most of these tumors present as a painless mass of the maxilla or mandible, often accompanied by loose teeth. Surgical resection achieving negative margins remains the crucial element in the treatment of head and neck osteosarcomas. It has been repeatedly shown that surgical margin status correlates significantly with local control and survival. In those cases in which margins were positive following resection, 5-year survival decreased dramatically to 35% from approximately 75% in those individuals with negative margins. In one series, positive margins were shown to be uniformly fatal at 4 years after treatment. Most recent experiences with this disease have been with multimodality therapy. Several centers have applied external beam irradiation in the postoperative period, particularly in cases of high-grade tumors, large lesions, close or positive margins, or inoperability. Unfortunately, radiation, whether delivered externally or as brachytherapy, does not appear to significantly improve overall survival in head and neck osteosarcomas. The addition of chemotherapy, however, has shown greater promise as an adjuvant modality in the treatment of osteosarcomas, especially in those individuals with lesions of the extremities. In a meta-analysis of 201 patients with craniofacial osteosarcomas, Smeele and colleagues suggested that chemotherapy increases survival even in those cases of incomplete surgical resection. Nevertheless, other series and meta-analyses have not shown such promising results. Five-year survival in larger series is only 42% to 55%, and disease-free survival at 5 years is achieved in only 25% to 30% of all patients. Combinations of surgery and chemotherapy, and possibly even radiation, for these aggressive neoplasms may provide better outcomes. Data continue to accrue, and future treatment protocols will be instituted based on these experiences.

Angiosarcoma
Angiosarcomas are exceedingly rare vascular sarcomas, but approximately 50% of all angiosarcomas occur in the head and neck region. These lesions classically present as bruiselike macules and plaques on the forehead and scalp of elderly white males. Because of their innocuous appearance and lack of symptoms, diagnosis is often delayed. Optimal treatment, however, is not clearly defined because of the rarity of angiosarcomas and their almost universally poor prognosis. The ability of these neoplasms to spread subcutaneously over relatively large areas makes local recurrence a defining quality of these malignancies. Therefore, truly negative surgical margins are unlikely to be achieved, and postoperative wide-field radiation therapy has been employed with increasing frequency and success at local control. With 5-year survival rates ranging from only 12% to 33% and with death commonly resulting from distant metastases, chemotherapy may have an emerging role in the management of angiosarcomas.

Rhabdomyosarcoma
Rhabdomyosarcoma is a significant disease of childhood and adolescents. It comprises approximately 4% to 8% of all pediatric cancers and is the most common sarcoma of childhood. Approximately 40% of all rhabdomyosarcomas originate in the head and neck region, and of these, 90% affect children. Furthermore, rhabdomyosarcoma accounts for up to a quarter of all head and neck sarcomas. Histologically, rhabdomyosarcomas are divided into four subtypes: embryonal, alveolar, botryoidal, and pleomorphic; this classification is clinically relevant as alveolar rhabdomyosarcomas are associated with significantly decreased survival when compared with the other histologic types. Further classification in children is based on the head and neck site, defined as orbital, parameningeal, or nonparameningeal. The orbit is the most common site in children whereas the sinonasal tract is the most common head and neck site in adults. The particular head and neck site of origin correlates with prognosis and has therefore been incorporated into the tumor, node, metastasis (TNM) staging system. Surgicopathologic criteria have also been used by the IRSG to stage rhabdomyosarcomas in pediatric patients according to local extension, regional and distant metastases, and the amount of residual tumor remaining after resection. (The IRSG was founded in 1972 and has since established standard treatment algorithms based on a combination of these staging systems for rhabdomyosarcomas in children and adolescents.) Complete surgical resection remains a critical component of therapy for these patients. However, comprehensive resection is not always possible with sarcomas of the head and neck region because of involvement of vital structures or unacceptable functional or cosmetic morbidity. Consequently, chemotherapy and radiation therapy are used as the primary treatment modalities in many patients with rhabdomyosarcoma of the head and neck region.490 Advances in the treatment of pediatric patients with rhabdomyosarcoma are reflected in the dramatically improved overall survival rate. Since 1970, the survival rate for all patients diagnosed with rhabdomyosarcoma has increased from approximately 25% to 70%, mostly as a result of the ongoing IRSG studies. Survival data for adult patients are somewhat limited, but overall outcomes are likely significantly worse than those reported for children.

Malignant Fibrous Histiocytoma
Malignant fibrous histiocytomas (MFHs) represent the most common variety of soft-tissue sarcoma, and it is one of the most common of all head and neck sarcomas. As with other sarcomas, MFH usually presents as a painless mass, and other symptoms are highly dependent on the particular structures involved. In the head and neck area, these lesions are generally evenly distributed among the sinonasal tract, UADT, and parotid gland. Adequate review by experienced pathologists can not be overemphasized. Fibrous lesions, including MFHs, have a broad spectrum of similar histologic features but significantly different prognoses. Treatment of MFH of the head and neck is preferably accomplished with wide surgical excision of the primary tumor, obtaining negative margins. Postoperative radiation therapy is recommended for unresectable lesions and in cases of close or positive margins. However, improved local control, especially for MFHs of other anatomic sites, has been achieved in some series using adjuvant radiotherapy regardless of margin status. Adjuvant chemotherapy for MFH remains investigational and has so far been used mostly in the setting of metastatic disease. Adjuvant chemotherapy may have a role, based on the report of the Sarcoma Meta-analysis Collaboration Group, which found improved recurrence-free intervals but not a statistically significant survival advantage. Overall 5-year survival rates following treatment for malignant fibrous histiocytoma of the head and neck region average 40% in larger series. Local recurrences are seen in approximately 20% of patients, but most disease-related deaths result from distant metastases, usually of the lungs.

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Provided by ArmMed Media
Revision date: July 4, 2011
Last revised: by Dave R. Roger, M.D.