Abstract
Purpose
Sinonasal rhabdomyosarcoma (SNRMS) is a rare malignancy which often presents with nasal obstruction, rhinorrhea and epistaxis. It is the most common sarcoma in children. In this study, we analyze the incidence and long-term survival for SNRMS using a national population-based database.
Methods
The United States National Cancer Institute’s Surveillance, Epidemiology, and End Results (SEER) registry was utilized to calculate incidence and survival trends for SNRMS between 1973 and 2009. In addition, data were grouped by age, gender, race, and histopathological subtype.
Results
A total of 181 cases of SNRMS were analyzed for incidence trends, showing a 1.23:1 female to male ratio. While the overall incidence of SNRMS increased by 1.02% annually over the last 20 years, this pattern was not equal amongst gender and racial groups. The incidence in males has increased, while in females incidence has decreased. An increase in incidence was noted in white and “others,” but decreased in blacks. Using a total of 314 cases for survival analysis, we found that the rate in the white population has been consistently highest with a 5-year survival of 49.45%, 10- and 20-year survival of 48.81%. Survival rates in cases of embryonal SNRMS were also consistently higher than in cases of alveolar SNRMS.
Conclusion
Overall incidence of SNRMS is increasing. Histologic subtype and race are important considerations in the long-term prognosis of SNRMS. Future studies will further elucidate gender and race related trends.
1
Introduction
Rhabdomyosarcoma (RMS) is the most common malignant soft-tissue tumor of the nose and paranasal sinuses in children . Prognosis depends on a combination of patient age, histologic character, clinical stage, and tumor location. RMSs are generally divided by meningeal and parameningeal sites . Parameningeal sites include middle ear, nasal cavity, paranasal sinuses, nasopharynx, and infratemporal fossa . Because of the risk of intracranial extension via the parameningeal locations, sinonasal rhabdomyosarcomas (SNRMSs) often have a poor overall prognosis . Tumors may present as painless, asymptomatic masses, or with symptoms of nasal obstruction, epistaxis, and rhinorrhea.
Several different histological types of rhabdomyosarcoma of the head and neck region have been identified, including embryonal, alveolar, pleomorphic, and mixed . Embryonal and alveolar patterns are more prevalent. Histologically, embryonal RMS consists of spindle and primitive round cells with rhabdomyoblasts and alveolar RMS consists of malignant cells bundled by fibrovascular septa to form alveolar-like spaces . In terms of survival, the alveolar pattern is associated with a poorer prognosis than the embryonal pattern . The embryonal form is often found in the head and neck region .
While definitive diagnosis requires a biopsy, the diagnosis of SNRMS may be suggested based on a thorough history, as well as radiographic imaging such as CT and MRI . SNRMS is often treated with a combination of chemotherapy, radiotherapy, and surgical resection .
A 2011, SEER analysis of all head and neck RMSs by Turner et al. reported an approximate 5-year survival rate of 62.8% . However, that study focused on all head and neck RMSs and did not go in depth into some of the specific details of SNRMS. This current study expands on Turner’s findings in that it reports additional important information in the SEER database specific to SNRMS not previously discussed in the literature. In this study, we expand the knowledge on these rare tumors by exploring the trends in incidence and uncovering prognostic factors influencing the long-term survival of SNRMS. To our knowledge, this is the first study utilizing the Surveillance, Epidemiology, and End Results (SEER) registry to evaluate the incidence of SNRMS based on gender, race, and histopathology, and its long-term survival trends.
2
Materials and methods
The SEER registry of 1973 to 2009 was accessed using SEER*Stat 8.0.1 (Surveillance Research Program, National Cancer Institute, 2012) to calculate the incidence and survival for the population used in this study. Institutional Review Board approval was not required for this study, as the SEER database is free of any sensitive patient information or identifiers. The SEER database is comprised of registries from numerous geographical areas of the United States. The SEER 18 registry, which is used to extract survival statistics, includes cancer data from 18 states and several metropolitan areas covering approximately 28% of the United States (US) population. In contrast, the SEER 9 registry, which is used to compare incidence data, encompasses information for 9.5% of the US census. The International Classification of Diseases for Oncology, 3rd edition [ICD-O-3] site code was used to extract data of primary malignant tumors of the nasopharynx (C30.0), Nasal Cavity (C11.0, C11.1, C11.2, C11.3, C11.8, C11.9), and paranasal sinuses (C31.0, C31.1, C31.2, C31.3, C31.8, and C31.9). Primary rhabdomyosarcomas (ICD-O-3 histologic code 8900–8921) of the sinonasal tract were then extracted and analyzed for frequencies, incidence rates, and relative survival. Due to the population size difference between the two registries, 314 patients with SNRMS were identified for survival analysis, and 181 patients with SNRMS were studied for incidence trends.
Relative survival analysis was also extracted for race (white, black, or “others”) and gender at 3-month intervals for a total period of 240 months using Kaplan–Meier analysis from the SEER 18 Registry. The category of “others” within the race demographic includes American Indian, Alaskan Native, Asian/Pacific Islander, unspecified, or unknown. The relative survival data were expressed as the observed rate of survival adjusted to the expected survival rate of the population in the US based on the time period and demographic studied. Incidence rate data were adjusted to the year 2000 U.S. standard population and was obtained as incidence per 100,000 people in the population of study. Analysis of data was completed using SEER*Stat 8.0.1, Microsoft Excel Software (Version 2010; Microsoft, Redmond, WA), and Joinpoint Regression Program 3.5.4 (National Cancer Institute, Bethesda, MD). Comparison between the survival curves was performed using a log rank test for significance with a p-value of < 0.05. All analyses were computed using JMP Statistical Discovery (SAS Institute, Cary, NC).
2
Materials and methods
The SEER registry of 1973 to 2009 was accessed using SEER*Stat 8.0.1 (Surveillance Research Program, National Cancer Institute, 2012) to calculate the incidence and survival for the population used in this study. Institutional Review Board approval was not required for this study, as the SEER database is free of any sensitive patient information or identifiers. The SEER database is comprised of registries from numerous geographical areas of the United States. The SEER 18 registry, which is used to extract survival statistics, includes cancer data from 18 states and several metropolitan areas covering approximately 28% of the United States (US) population. In contrast, the SEER 9 registry, which is used to compare incidence data, encompasses information for 9.5% of the US census. The International Classification of Diseases for Oncology, 3rd edition [ICD-O-3] site code was used to extract data of primary malignant tumors of the nasopharynx (C30.0), Nasal Cavity (C11.0, C11.1, C11.2, C11.3, C11.8, C11.9), and paranasal sinuses (C31.0, C31.1, C31.2, C31.3, C31.8, and C31.9). Primary rhabdomyosarcomas (ICD-O-3 histologic code 8900–8921) of the sinonasal tract were then extracted and analyzed for frequencies, incidence rates, and relative survival. Due to the population size difference between the two registries, 314 patients with SNRMS were identified for survival analysis, and 181 patients with SNRMS were studied for incidence trends.
Relative survival analysis was also extracted for race (white, black, or “others”) and gender at 3-month intervals for a total period of 240 months using Kaplan–Meier analysis from the SEER 18 Registry. The category of “others” within the race demographic includes American Indian, Alaskan Native, Asian/Pacific Islander, unspecified, or unknown. The relative survival data were expressed as the observed rate of survival adjusted to the expected survival rate of the population in the US based on the time period and demographic studied. Incidence rate data were adjusted to the year 2000 U.S. standard population and was obtained as incidence per 100,000 people in the population of study. Analysis of data was completed using SEER*Stat 8.0.1, Microsoft Excel Software (Version 2010; Microsoft, Redmond, WA), and Joinpoint Regression Program 3.5.4 (National Cancer Institute, Bethesda, MD). Comparison between the survival curves was performed using a log rank test for significance with a p-value of < 0.05. All analyses were computed using JMP Statistical Discovery (SAS Institute, Cary, NC).
3
Results
3.1
Demographic analysis
Of the 181 patients, 58.0% of cases were younger than the age of 20 years and 37.02% were younger than 10 years of age ( Fig. 1 ). In this analysis, 55.25% of cases were seen in females, while 44.75% of cases were males, with a female to male ratio of 1.23:1 ( Table 1 ). In addition, 76.80% of SNRMSs involved whites, 14.92% were black patients, with the remaining 8.29% of patients identifying themselves as “other”. The primary tumor site was most commonly in the paranasal sinuses, seen in 51.93% of patients. The nasopharynx and the nasal cavity were the next most common sites, seen in 32.6% and 16.02% of cases, respectively.
| Characteristic | No. | % |
|---|---|---|
| Gender | ||
| Male | 81 | 44.75% |
| Female | 100 | 55.25% |
| Race | ||
| White | 139 | 76.80% |
| Black | 27 | 14.92% |
| Other | 15 | 08.29% |
| Primary Site | ||
| Nasal cavity | 28 | 16.02% |
| Nasopharynx | 59 | 32.60% |
| Paranasal | 94 | 51.93% |
3.2
Incidence analysis
The overall incidence of SNRMS stands at 0.034 cases per 100, 000 and has steadily increased over the last 20 years. Due to the small number of SNRMS from 1973 to 1989, an incidence analysis was conducted from 1989 onwards to appropriately depict the long-term incidence trends of these tumors. The Joinpoint regression model revealed an increasing overall incidence of SNRMS with an annual percentage change (APC) of 1.02% (95% CI: − 1.3%, 3.4%, p > 0.05) ( Fig. 2 ).
