Epidemiology of musculoskeletal tumors in Sardjito hospital Yogyakarta Indonesia

One of the main causes of mortality in the world are malignant neoplasms. These neoplasms can occur in musculoskeletal system either as a primer or metastasis from other organs such as breast, kidney, lung and thyroid [1],[2],[3]. Diagnosis of neoplasms is very important because it determines subsequent management planning.

Primary bone tumors are often diagnosed late, due to their rare incidence, about 0.2–0.5% of all malignancies at all ages [4], with 3–5% of these tumors diagnosed in children under 15 and 7–8% between the ages of 15 and 19 years in European [5]. Signs and symptoms are often nonspecific. Usually suspected and treated as osteomyelitis or simple fracture before finally getting the right diagnosis. The incidence of primary bone tumors is about 9 in 1 million people worldwide, where in men slightly more common (10 in 1 million) than in women (8 in 1 million) [6]. To improve diagnosis and preliminary procedures, epidemiological studies are needed in each region. These studies will also help and guide the researchers to look for any specific risk factors in the area. Previous studies show Europe and USA have higher incidence and prevalence rates of primary bone tumor than Asia [5],[7],[8].

We collected data on patients underwent either open or excisional musculoskeletal biopsies at Sardjito general hospital in Yogyakarta from January 2011 to December 2014, retrospectively. Data were then divided by sex, age, anatomical site and histopathologic type, whereby the diagnosis was upheld according to the results of clinicopathologic conferences according to clinical presentation and radiographic findings. Tumors are then classified into benign bone tumors, malignant bone tumors, and soft tissue tumors. Soft tissue tumors are just malignant ones such as fibrosarcoma, rhabdomyosarcoma, and so on. Whereas benign soft tissue tumors were not included.

Totally, 122 cases were analyzed. Male to female ratio was 1.07. There were 59 women (48.4%) and 63 men (51.6%). The oldest patient was an 81-year-old man with metastasis. Table 1 shows that the most common anatomical site of bone tumors was the femur (38; 35.5%), followed by the tibia (21; 19.6%) and the humerus (17; 15.9%). The peak frequency in age of patients are between 5 and 25 years. And in patients younger than 25 years old shows a large population of benign bone tumors (27; 60.0%). In the age group of 35-54 years, soft tissue tumors occured more (6; 40.0%). The youngest patient reported was a 1-year-old child with chondroblastoma.

Benign bone tumors

The giant cell tumor (22; 48.9%), osteochondroma (8; 17.8%), aneurysmal bone cyst (3; 6.7%) were the most frequently occuring tumors. In adults patients with third and fourth decades of life, giant cell tumors were seen mostly (Table 2). Table 3 shows osteochondroma and aneurysmal bone cyst are often affect men more as compared to women. While women are in higher risk (61.9%) of suffering from giant cell tumor. Also, about half of the cases of osteochondroma belonged to 15–25 years (62.5%) and aneurysmal bone cyst belonged to 5–14 years (60.0%).

Malignant bone tumors

The most common malignant neoplasms was osteosarcoma (22; 35.5%), followed by metastasis (17; 27.4%), and chondrosarcoma (7; 11.3%), of a total 62 malignant neoplasms. Men were more frequently affected by osteosarcoma and chondrosarcoma than women and more frequent in the 14–24 years age group. The ratio for osteosarcoma comparison in men as compared to women was 1.75, while the ratio for chondrosarcoma was 1.3 (Table 3).

Soft tissue tumors

The anatomic location of soft tissue tumors most commonly found on wrist-hand (5; 33.3%), thigh (4; 26.7%), elbow joint (4; 26.7%) and leg (2; 13.3%). Of all cases, 15 cases of malignancy in soft tissue were found, and women were more frequently affected (10; 66.7%) than men.

Musculoskeletal tumors in patients over 40 years

In this group, there were 44 patients, 23 (52.3%) were men and 21 (47.7%) were women.Table 4 shows that most malignat bone tumors are osteosarcoma (4; 9.1%), whereas benign bone tumors are mostly giant cell tumors (6; 13.6%). The table also shows the most pathology in this group is metastasis (15; 34.1%), followed by soft tissue tumors (10; 22.7%).

Anatomical site distribution

The most common site of malignant bone tumors in long bone involved was the femur, followed by the humerus (12; 19.4%) and the tibia (8; 12.9%). While in benign neoplasms, femur was also the most commont site involved, followed by the tibia (13; 28.9%) and the wrist-hand (9; 20.0%). Table 5 is illustrating anatomical site distribution of specific tumors, showing there is a case of osteosarcoma involving of more than one bone, the femur and the tibia.

Previous studies show that the relative 5-year survival rate is 53.9% for osteosarcoma, 75.2% for chondrosarcoma, and 50.6% for Ewing’s sarcoma [9]. Although primary bone tumors only contribute 1% of all malignancies [4],[10], they have a high mortality rate. Better diagnostic and management strategies require regional description and distribution data of musculoskeletal tumors that are one of the causes of morbidity and mortality worldwide. According to previous studies, osteosarcoma is still the most frequent primary bone malignancy [6]. It was reported that osteosarcoma contributed 35-68% of all malignant bone tumors [11],[12]. This is similar to what we found in our study in Yogyakarta, ososarcoma was found 35.5% of the total patients. The greatest number was found in age under 25 years (16; 72.7%) and there were no patients under five years of age. The ratio between men and women is the same as other studies which is about 1.75. Ranked second in the primary bone malignancy is chondrosarcoma (11.3%), followed by Ewing Sarcoma (4; 6.5%). Our results are similar to those reported in a study by Rao et al. [13] in India and by Shah et al. [11] in Pakistan. Most reports from developed countries explain chondrosarcoma as the second most frequent. Ewing’s sarcomas are tumors of the young, with 80% occurring in patients under 20 years. They rarely occur above the age of 30 [5]. We did not have any Ewing’s sarcoma patient older than 35 years. In our study, the most frequent benign bone tumor was giant cell tumor, followed by aneurysmal bone cyst and osteochondroma. Giant cell tumor accounted for 46.7% of benign bone tumors and 19.6% of all bone neoplasms. The second most frequent benign neoplasm, osteochondroma, accounted for about 17.8% of cases, wherein 62.5% cases were diagnosed in femur and tibia. Humerus was the next most common site. Giant cell tumors, as the second most common benign tumors in several studies [14],[15], represent about 5% of all bone tumors. In our study, it is the most frequent benign tumor. It was seen in 21 patients (19.6%) with involvement of the femur (19.0%), tibia (23.8%), and hand (23.8%) in order of frequency. The real frequency of this tumor may be more in our population because of its clinical diagnosis by radiographs.

Metastasis from other sites [2],[3] and multiple myeloma are the most likely diagnosed bone lesions in patients older than 40 [16]. Metastatic carcinoma and soft tissue tumors were the most prevalent diagnosed bone tumors in older patients. Giant cell tumor (6; 13.6%) and osteosarcoma (4; 9.1%) were the common primary benign and malignant bone tumors, respectively.

Late diagnosis and poor prognosis of musculoskeletal tumors are associated with some reasons. Nonspecific clinical symptoms, just like pain and swelling, which are more common in other musculoskeletal diseases than tumors, and unfamiliarity of general medical staff to the symptoms, besides the rarity of musculoskeletal tumors, are some of the causes. Epidemiologic studies based on e-databases in each region help in rapid diagnosis and management. This study has no significant difference related to epidemiology of musculoskeletal tumors with others in literature.

Epidemiology of musculoskeletal tumors in Yogyakarta, in comparison with other parts of the world, are no significant differences. This report represents a first of its kind in our region, and gives representative results to be compared to other South East Asia region.