Shining a light on Sarcomas: An Interview with Dr Björn Jobke

Sarcomas, a diverse group of malignancies, pose unique challenges in the realm of oncology. Unlike more common cancers such as breast or lung cancer, sarcomas arise within different origin tissue types including bone, fat, muscle, and connective tissue and proliferate into different cell lineages, called differentiation. This differentiation of tissues contributes to the diversity of sarcomas, with over 50 recognised subtypes, each with distinct clinical, pathological, and molecular characteristics. Sarcomas can affect individuals of all ages and may arise anywhere in the body. Due to their rarity and diverse presentations, sarcomas often elude early detection and diagnosis. 

Hence, we are very fortunate to have sarcoma imaging expertise within Unilabs. We spoke to radiologist Dr Björn Jobke, sarcoma imaging expert, to get his insights on this challenging area of oncology.

As an expert in sarcoma imaging, what are some of the most intriguing or challenging cases you've encountered, and how did you approach their diagnosis?

There are two categories of challenges with bone or soft tissue tumours. First, incidental findings, which are findings, unrelated to the indication of the imaging study and the patients do not present related symptoms. This group is extremely rare for malignancies and more commonly seen in benign bone and soft tissue tumours, but a definitive diagnosis is not always possible and may warrant further diagnostics or biopsy. Statistics and probabilities play a big role in the diagnostic process of bone sarcomas particularly. Aside from imaging features, the age of the patient and the location of the tumour are key criteria for many entities. While the overall age spectrum for all sarcomas is large, certain sarcomas only appear in a certain age group.  Data from large case collections in tumour centers are needed to obtain these statistics. The second main group of challenges are symptomatic tumours and their differential diagnosis. There is significant overlap between different tumour imaging features and only the synopsis of two or more modalities (e.g. X-Ray + MRI) and a minimum of several years of experience in seeing these rarities, result in a high specificity for a diagnosis. The consequences for the patient, of receiving a sarcoma diagnosis have a significant impact on quality of life and require a multi-modal treatment approach to reach moderate survival rates. My job as a radiologist is to avoid unnecessary invasive diagnostics or treatments if malignancy can be excluded with the appropriate imaging modality with a very high likelihood. I remember a case from my time as a resident in Bone Pathology when we received a resected femoral head (the ‘ball’ at the top of the thigh bone) from the hip of a younger patient with uncontrollable hip pain. After a thorough investigation of the specimen, the patient turned out to have a tiny (3mm) benign tumour, that is known to cause severe pain. If identified earlier with dedicated imaging review and expertise, the patient could have avoided a hip replacement which is a life-changing, invasive procedure and been treated definitively with a minimally invasive technique. 

Given the rarity and heterogeneity of sarcomas, how do you stay updated on the latest research, guidelines, and best practices in sarcoma radiology, and how do you incorporate this knowledge into your day-to-day? 

A good knowledge foundation is the most important criteria for confident MSK tumour imaging diagnostics. A multi-year-long experience in speciality centres, multi-disciplinary meetings and hundreds of case discussions with feedback loops are needed since some entities are so rare that even experienced doctors have only seen a handful of examples of these sarcomas. Implementing a Bone and Soft Tissue Expert Group within Unilabs MSK Section some years ago has also contributed significantly to continuously being confronted with these cases and discussing them within the team. Staying up to date with nomenclature and classifications becomes more and more difficult since the molecular heterogeneity of sarcomas is becoming more diverse by the year but e.g. the tumour subcommittee of the European Society for Skeletal Radiology regularly shares updates. I try to attend a biannual meeting of a multi-disciplinary bone tumour working group (Arbeitsgmeinschaft Knochentumoren) in Germany. 

What are some of the emerging trends or developments in sarcoma radiology, and how do you envision these advancements shaping the future of sarcoma care?

Next-generation sequencing has led to very high specificity from some sarcomas which reduces time-to-diagnosis and may result in better-targeted treatments. The biomolecular field appears to evolve much faster than novel imaging techniques to improve accuracy. It has been stagnant for a while. Until Artificial Intelligence will support general radiologists in catching these rare cases - currently limited by small cohort sizes for training AI models - we will have to continue to teach young radiologists early on and transfer valuable knowledge acquired over decades. At least for bone tumours, the oldest imaging technique available – X-Rays- is a still an undeniable cornerstone as the baseline diagnostic. For tissue characterisation, it would be very helpful to have specific molecular imaging information, but clinical developments are stagnant.

Lastly, reflecting on your career in sarcoma radiology, what are some key lessons or insights you've gained that have shaped your approach to patient care and professional development?

Sarcoma imaging diagnostics is clinical radiology that requires more than unique imaging features to reach high diagnostic accuracy. That’s very tricky in teleradiology and hence it comes with a great responsibility to take on such cases. To some extent, one can compensate for the lack of clinical information by bringing in year-long experience from the clinical world. Before I went into Radiology, I was very fortunate to start my career path with several years of residency in a highly specialised Bone Pathology Department in Hamburg, Germany. This experience, with daily radiological-pathological correlations, has deeply shaped my knowledge of bone and soft tissue tumors that I am still trying to translate into practice today.