When the term "orthopedic surgeons" comes to mind, we often associate it with trauma, fractures, spine, and prosthetic joints. These areas attract a significant number of patients and present a wide range of cases. However, my specialization lies in musculoskeletal oncology, a field that prompts many to ask, "Does that really exist?" In essence, I am an orthopedic surgeon dedicated to treating tumors affecting the bones and muscles.

People often inquire, "Can bones and muscles really develop cancer?" The answer is yes, although it is exceedingly rare. I frequently encounter surprised reactions when discussing my field. Some assume, "Oh, you mean bone marrow cancer?" However, it's important to clarify that although cancers may be found in the bones, myeloma is a type of blood cancer. Nevertheless, cancers can indeed manifest in bones and muscles, albeit infrequently.

It is interesting to note that approximately three-quarters of our body weight comprises the musculoskeletal system. Considering this, one might assume that three-quarters of all cancers would also be musculoskeletal in nature. However, fortunately, musculoskeletal cancers actually account for less than 1 percent of all cancer cases.

Why are there so few musculoskeletal cancers? Cancer tends to thrive in tissues where there is a constant turnover of cells, with old cells dying and new cells being born. Consider the digestive system, for instance. After eating hot food, you may have experienced the discomfort of a sore mouth that takes a couple of days to heal. This is because the digestive system is a highly active area where cells are continuously generated and replaced. Consequently, the digestive system is prone to a higher incidence of cancers.

A similar principle applies to the blood. The bone marrow constantly produces new cells, making blood cancers quite common. However, bone and muscle are comparatively less active tissues. They have lower rates of cell turnover, making it highly unlikely for them to develop cancer. Nonetheless, it remains intriguing that cancers can still arise in these relatively quiet tissues.

Why did I pursue a major in this field? Part of the reason was the rarity of cases, which piqued my interest, and partly because it held academic intrigue. When I was deciding on my specialization, many expressed concerns about the challenging nature and limited patient pool. However, I questioned, "Why should I settle for less?" It took me some time to secure a stable position, but I was determined to pursue my passion. Nowadays, I often ponder whether newly graduated medical students choose their specialties based on scarcity or intrinsic value. Regardless, I always advise my students to select something meaningful and valuable, something they genuinely desire, even if it appears perplexing or unconventional. 

Indeed, bone cancers are more commonly observed as metastatic cancers, meaning they originate from cancer cells that have spread to the bone from another primary site in the body. Spontaneous cancers that originate directly in the bone itself are relatively less common. Lung cancer and breast cancer are among the typical types of cancers that tend to metastasize to the bone. However, due to advancements in medical treatments and improved survival rates, the number of patients with naturally occurring bone metastases is on the rise.

While metastatic cancers are a significant concern, specialists primarily focus on addressing cancers that originate within the bone or muscle itself. Among primary bone cancers, osteosarcoma stands as one of the most frequently encountered types.

Osteosarcoma, most common around the knee between the ages of 12 and 15

As previously mentioned, cancer tends to develop in areas where cellular changes and growth are rapid. This is why osteosarcoma commonly occurs during adolescence, typically between the ages of 12 and 15, which coincides with the period of reaching full height. Osteosarcoma often manifests around the knees, as this is where growth is most pronounced. While osteosarcoma is rare before the teenage years, it can also be found in individuals in their 20s and even between the ages of 5 and 60. However, the characteristic and typical presentation of osteosarcoma is most frequently observed in the early to mid-teens. The general pattern is as follows:

There is a boy in the first grade of middle school who has a passion for sports. He experiences occasional knee pain but continues to play without proper assessment. Due to his young age and a desire to respect his privacy, his knee is not checked for swelling by concerned parents during his middle school years. Unfortunately, this can result in a missed diagnosis, despite an underlying condition worsening. Additionally, early-stage osteosarcoma is challenging to detect through plain x-rays, leading parents to seek reassurance from orthopedic surgeons who may initially find no issues. However, as time progresses, evident problems arise, yet they can be dismissed as overuse injuries due to the child's active lifestyle. As a general rule, it takes approximately four to six months from the onset of symptoms for a diagnosis to be made. By this time, the affected knee may be severely swollen, causing difficulty in walking properly. Given the rarity of osteosarcoma, it is possible for an orthopedic surgeon who is establishing their clinic to lack experience in diagnosing and treating this specific condition, emphasizing the importance of taking such symptoms seriously.

For the record, it's very common for children to complain of knee pain, but what we call “growing pains” do not occur after the age of 10. Growing pains are not found in any medical textbooks, but only in children before the age of 10, especially in pre-school children who have not yet completed their body image. It is necessary to pay attention to it after that period, but this is sometimes overlooked, causing the doctor of an orthopedic clinic to be confused and the parents to despair.

Typically, the diagnosis process for osteosarcoma unfolds as follows. While a delay of several months in reaching a diagnosis can be detrimental to the patient, it is important to note that there is no definitive way to predict when the disease will be detected and the likelihood of successful treatment will increase. The nature of the disease is such that the effectiveness of treatment is not solely dependent on the timing of the diagnosis.

Professor Park Jong-hoon graduated from Korea University College of Medicine in 1989 and became an orthopedic surgeon in 1997. His specialty is musculoskeletal oncology. He served as head of the Department of Orthopedic Surgery at Korea Cancer Center Hospital. Since 2007, he has been treating patients with musculoskeletal tumors at the Department of Orthopedic Surgery of Korea University Anam Hospital.  He trained at the National Cancer Center in Japan in 2011. He is interested in the minimally transfused or transfusion-free treatment of musculoskeletal tumors. He also served as the director of Korea University Anam Hospital and the director of the Korea Institute of Radiological & Medical Sciences.

This contribution article was originally published in Korea Healthlog, a sister paper of Korea Biomedical Review, on June  9. -- Ed.