Exploring Bone Oncology in a Medically Underserved Area: A Retrospective Cohort of Bone Metastases and Malignant Bone Neoplasia in the Rio Grande Valley

The Rio Grande Valley is a demographically unique region of southern Texas. This study explores the frequency and demographics associated with bone metastases and primary malignant bone neoplasia in this unique region. The rates of bone metastases and primary malignant bone neoplasia differed significantly from the national average. As such, this study warrants further exploration in this unique region and possibly other medically underserved regions.

Abstract

Objectives

The Rio Grande Valley (RGV) is a developing clinical research region characterized by its distinctive demographic profile that offers an opportunity to investigate diverse health issues. This pilot investigation sought to evaluate the demographic and clinical characteristics linked to bone metastases and primary malignant bone neoplasms (PMBNs) in patients from the RGV and to compare the frequency of these conditions with the US general population.

Methods

This was a retrospective chart review in which data were gathered from the University of Texas Rio Grande Valley UTHealth electronic database from January 1, 2018 to September 4, 2024. Various statistical analyses were performed to assess the demographic and clinical data.

Results

Individuals in the RGV are more likely to develop a PMBN (P < 0.0163) but less likely to have bone metastasis (P < 0.0015) compared with the general US population. Regarding bone metastases and PMBN, although not statistically significant, patients with bone metastasis were 10 years older on average and exhibited a lower body mass index (−1.7 kg/m²) and weight (−17.6 kg) than those with PMBN.

Conclusions

Our initial research indicates age and body weight variations among individuals with bone metastases and PMBN in the RGV, as well as differences in frequency of bone metastases and PMBN in this medically underserved region compared with the general US population. Despite the limited sample size, our results necessitate further exploration in a larger cohort to elucidate any demographic and clinical differences in bone metastases and PMBN subtypes in medically underserved areas.

Key Points

• Weight and body mass index vary between individuals with bone metastases and primary malignant bone tumors.

• Individuals in the Rio Grande Valley are more likely to develop primary malignant bone neoplasms.

• Individuals in the Rio Grande Valley are less likely to have bone metastases.

Bone metastases are malignant neoplasms that have spread to the bone from other structures. Some of the more common locations from which bone metastases spread are the prostate, breast, kidney, thyroid, and lungs.¹ The skeleton is the third most common site of metastatic disease after the lung and the liver.¹ Metastases may present with a single bone lesion, oligometastatic disease, multiple bone metastases, or visceral plus bone metastases.¹ Primary malignant bone neoplasms (PMBNs), which account for 0.2% to 1% of human neoplasms, are mesenchymal tumors with a wide range of morphological and biological behaviors that have a tremendous impact on patients’ life expectancy and quality of life.² Osteosarcoma (most common), Ewing sarcoma, chondrosarcoma, and chordoma are the four most common types, which initially present with pain and a mass at the primary site.²

Bone metastases affect survival rates ranging from 6 to 7 months in lung cancer to several years in breast (19–25 months) or prostate cancer (12–53 months).¹ In PMBNs, the mean survival times of patients with osteosarcoma, chondrosarcoma, Ewing sarcoma, and chordoma are approximately 54.9, 63.5, 58.1, and 66.9 months, respectively.² Metastasis of PMBNs was found to be a significant cause of high mortality and worse prognosis in these patients, with metastasis usually occurring hematogenously and the lungs and bones being the most common metastatic sites.²

It is important to identify bone metastasis and PMBNs early, both for staging and prognostication, as well as the implementation of prophylactic and treatment strategies, which may lead to decreased morbidity and mortality.^1,3 The treatment/management of bone metastases should be a multidisciplinary approach targeted at preserving the quality of life, including pain control, minimizing skeletal related events, and achieving local tumor control when possible.¹ For PMBNs, the diagnostic modalities used include imaging (computed tomography, magnetic resonance image, X-ray, positron emission tomography), laboratory blood tests, and tissue biopsy.³ Managing primary bone cancer requires a multidisciplinary approach that depends on several factors, including tumor type, stage and grade, and patient preference.³ Surgical excision remains the cornerstone of primary bone cancer treatment with neoadjuvant and adjuvant chemotherapy also being commonplace in management.³

The Rio Grande Valley (RGV) is a developing clinical research region characterized by its distinctive demographic profile that offers an opportunity to investigate diverse health issues. This community has a high prevalence of chronic conditions, such as obesity and diabetes mellitus.⁴ This region also is medically underserved, impoverished, and has a large population of undocumented immigrants.^5,6 The “machismo” construct is another factor that may further contribute to the health of this region, as this may deter Hispanic males from seeking medical care due to it being perceived as feminine.⁷ To our knowledge, no studies of bone metastases and PMBN have been performed in this unique region. We sought to use this pilot investigation to evaluate the demographic and clinical characteristics linked to bone metastases and PMBNs in patients from the RGV and compare the frequency of these conditions with the US general population. We hypothesized that increased age would show a greater frequency of bone metastases compared with PMBNs and that bone metastases would have an increased frequency in the RGV compared with the national population.

METHODS

Study Design and Data Collection

This was a retrospective chart review, and institutional review board approval was obtained before starting this study. Data were gathered from the University of Texas Rio Grande Valley (UTRGV) UTHealth electronic database. Data collection included medical charts from January 1, 2018 to September 4, 2024. Individuals’ charts were obtained via searching International Classification of Diseases, Tenth Revision (ICD-10) codes for bone metastases or PMBNs. Osteosarcoma, chondrosarcoma, and Ewing sarcoma were obtained using the ICD-10 code C41, which indicates malignant neoplasm of bone and articular cartilage. Bone metastases were obtained using the ICD-10 code C79.5, which indicates secondary malignant neoplasm of bone and bone marrow.

Inclusion and Exclusion Criteria

Individuals older than 90 years and individuals who were not seen by a facility associated with the UTRGV were not included in the study. Patient demographics that were included were age, sex, date at diagnosis, date of birth, body mass index (BMI), ethnicity, county of residence, and marital status. If an individual’s medical chart came up multiple times due to the individual having more than one appointment, the earliest date, the date the patient was diagnosed as having bone metastasis or PMBN, was included.

Data Analysis

Descriptive statistics were employed to assess the demographic and clinical data. Continuous data were summarized using the mean and standard deviation (SD), and categorical variables were represented as frequencies and proportions. Contrast analysis was conducted using the t test and χ², without any adjustments because of the limited sample size. The analysis used Stata version 18.5 (StataCorp, College Station, TX).

RESULTS

Of the 89,135 charts analyzed between January 1, 2018 and September 4, 2024, this study included 37 patients, nine (24%) with PMBNs. The average yearly incidence of PMBNs in our study was approximately 0.0015/100 people, whereas the average yearly incidence for bone metastasis was approximately 0.0047/100 people. The average age of the sample was 61.1 years (SD 16.7), with a mean BMI of 34.0 (SD 19.2). Significantly, 41% of the data were gathered in 2022, indicating a potential delay attributable to the coronavirus disease 2019 pandemic. We were unable to identify the average age and BMI for various PMBNs because the ICD-10 code includes them as a group and they could not be separated; however, individuals with bone metastases in our study had an average BMI of 35.2 (SD 9.0) and an average age of 54.7 (SD 26.3).

Table 1 delineates the group’s primary demographic and clinical attributes. Although females demonstrated a higher BMI than males, no statistically significant variations by sex were observed. Table 2 delineates the distinctions between patients with PMBNs and those with bone metastases. On average, patients with bone metastases were 10 years older and exhibited a lower BMI (−1.7 kg/m2) and weight (−17.6 kg) than those with PMBNs. Nonetheless, these disparities, were not statistically significant.

TABLE 1.

Descriptive statistics of characteristics of the study participants

TABLE 2.

Contrast between bone neoplasia by primary lesion or secondary to metastasis

DISCUSSION

The average yearly incidence of PMBNs in our study was approximately 0.0015/100 people, whereas the average yearly incidence for bone metastasis was approximately 0.0047/100 people. The American Cancer Society has stated that in 2023, approximately 3970 new cases of PMBNs were diagnosed (2270 in males and 1700 in females), with approximately 2050 deaths (1100 in males and 950 in females).⁸ Also, according to the American Cancer Society, approximately 400,000 new cases of malignant bone metastases are diagnosed in the United States each year.⁹ The estimated population of the United States in 2023 was approximately 336 million.¹⁰ This indicates that the yearly incidence of PMBNs in the United States was approximately 0.0012/100 people, whereas the yearly incidence of bone metastases in the United States was approximately 0.1190/100 people in 2023. These results show that the individuals in the RGV are more likely to develop PMBNs (P < 0.0163, 95% confidence interval 0–0.0001) but less likely to have bone metastases (P < 0.0015, 95% confidence interval 0.0003–0.0015) when compared with the general US population. Although our results were based on a small study sample size, they allow insight into what future studies should look for in addition to increasing the statistical power of the results.

The average age of our study sample was 61.1 years (SD 16.7), with a BMI of 34.0 (SD 19.2). Our study also showed that although females demonstrated higher BMIs than males, no statistically significant variations by sex were observed; however, 41% of the data were gathered in 2022, indicating that a potential delay attributable to the coronavirus disease 2019 pandemic may factor into the results. We were unable to identify the average age and BMI for various PMBNs because the ICD-10 code includes them as a group and they could not be separated. The average age of individuals with PMBNs (as a group) was not found in the current literature; however, the average age of various types of PMBNs were found, with osteosarcoma being 21, Ewing sarcoma being 15, and chondrosarcoma being 51 years old at diagnosis.^11–13 Our study does not relate to this current literature because we were unable to separate the types of PMBNs in our study and instead had to average the ages as a group. Individuals with bone metastases in our study had an average BMI of 35.2 (SD 9.0) and an average age of 54.7 (SD 26.3). One study showed that patients’ ages varied from 31 to 81 years, with most individuals having bone metastases in their sixth decade of life.¹⁴ This indicates that our study agrees with the current literature, with bone metastases occurring over a large range of ages and an average age around the sixth decade of life. To our knowledge, there is no literature that relates bone metastases or PMBNs to BMI; however, one study on breast cancer showed that although low BMI was associated with a higher number of metastatic sites, the frequency of bone-only metastases increased with increasing BMI.¹⁵ Our study somewhat agrees with this statement as our study’s average BMI of 35.2 is categorized as obesity class 2, which is near (one class away from) the upper end of the BMI classification scale.¹⁶ We were unable to find any studies that analyzed the relation between sex and BMI in individuals with bone metastases or PMBNs.

On average, patients with bone metastases were 10 years older and exhibited a lower BMI (−1.7 kg/m²) and weight (−17.6 kg) than those with PMBNs. Nonetheless, these disparities, saved from weight in kilograms, were not statistically significant. To our knowledge, there is no literature comparing the differences in ages or BMI between individuals with PMBNs and those with bone metastases. One study, however, analyzed a group of individuals who had PMBNs with or without bone metastases.² In this study, patients with bone metastases were younger than patients without bone metastases.² Although our study is not completely relatable to this study, our results show an opposite trend, with metastasis occurring in older individuals compared with metastasis occurring in younger individuals in the study by Xiao et al.²

Regarding limitations, data were collected solely from UTRGV UTHealth electronic databases, so individuals cared for at another institution not affiliated with UTRGV were not considered in this study. This study may not be completely generalizable to the population in south Texas for this reason. Most of the patients analyzed in this study were Hispanic, which indicates that our results may not be generalizable to the United States or another nation’s population whose landscape differs ethnically from the one in our study. The RGV also is an impoverished, medically underserved area with a large population of individuals without health insurance and of illegal immigrants.^5,6 This patient community is another reason the results of this study should be used with caution when relating them to other regions.

Some points that future studies should focus on are obtaining a larger sample size, including more demographic factors that could play a role in the probability of obtaining bone metastasis or PMBNs such as smoking, obtaining data from a less-biased population or database that may have greater generalizability, and analyzing the various PMBNs individually instead of as a group.

CONCLUSIONS

This initial research indicates age and body weight variations among individuals with bone metastases and PMBNs in the RGV, as well as differences in the frequency of bone metastases and PMBNs in this medically underserved region compared to the general US population. Despite the limited sample size, our results necessitate further exploration in a larger cohort to elucidate any demographic and clinical differences in bone metastases and PMBN subtypes in medically underserved areas.