Yogi Berra is credited with saying, “If you don’t know where you are going, you will wind up somewhere else.” If Yogi Berra were asked to give a historical perspective on the treatment of low-grade chondrosarcoma, he might have said, “If you don’t know where you’re starting from, you can’t get directions.”
Finding direction in the maze of treatment options for the management of low-grade chondrosarcoma has been impossible since orthopaedic oncologists, pathologists, and radiologists could not find a common starting point on the journey. For many years the management of so-called “low-grade chondrosarcoma” has been extremely controversial, and it remains so today. Much of the controversy has been the result of an inability to find agreement on what truly constitutes a low-grade chondrosarcoma (the starting point). The literature has been clouded by a lack of agreement as to the criteria for distinguishing “low-grade chondrosarcoma” from active enchondroma and Grade-2 chondrosarcoma1. Earlier classifications of chondrosarcoma based solely on histologic criteria have proven to be inadequate. Grading of tumors must account for the biologic behavior of the tumor, not simply the histology. Fundamentally, the grade of a tumor depends on the predicted biologic behavior locally and its potential for metastasis. In the case of low-grade chondrosarcoma, considerations other than histology include the anatomic location of the tumor, the radiographic appearance of the tumor, and clinical symptoms. If we were to rely on histology alone, many enchondromas of the digits would be classified as chondrosarcomas. What is now clear is that there are chondroid lesions of bone that are biologically more aggressive than enchondromas, are not static lesions, are prone to local recurrence after incomplete excision or curettage, and demonstrate histologic and radiographic features different from those of simple enchondromas. It is also clear that these lesions have histologic and radiographic features that distinguish them from Grade-2 or Grade-3 chondrosarcomas, that they are biologically less aggressive and are not prone to metastasis, and that they can be treated with intralesional procedures instead of wide resection, as has been advocated previously2. Yet despite this, understanding the optimal surgical management of Grade-1 chondrosarcoma remains controversial, with some authors still advocating wide resection and others recommending intralesional procedures.
Meftah et al. present the long-term functional and oncologic outcomes of forty-two patients (forty-three lesions) treated with extended curettage, cryosurgery, and cementation. The strengths of the article include consistent criteria used to define low-grade chondrosarcoma by a single pathologist specialized in sarcoma and review of all cases by an experienced musculoskeletal radiologist and other specialists. In each case, the diagnosis of low-grade chondrosarcoma was established on the basis of clinical, radiographic, and histologic criteria. The importance of establishing the diagnosis of low-grade chondrosarcoma in conjunction with clinical, radiographic, and histologic criteria and expertise cannot be overemphasized. Although the authors were unable to show a difference in results depending on the use of a cryoprobe compared with the direct-pour technique, intralesional curettage and cryosurgery resulted in a local recurrence rate of nearly 10% but without any cases of distant metastasis. Interestingly, all cases of local recurrence were in patients who had extraosseous extension of tumor into surrounding soft tissue. There are those who would argue that a tumor that extends through the cortex should be considered a Grade-2 lesion. In spite of including these tumors with soft-tissue extension, there were no cases of distant metastasis. There were, however, four cases of local recurrence in patients with extension of the tumor beyond the cortex and into the surrounding soft tissue. Two of these patients were managed with wide resection, one with repeat curettage and cryosurgery, and another with below-the-knee amputation. There is no information presented regarding why an amputation was performed and whether or not that lesion had remained low-grade or transformed to a higher grade.
The 67% prevalence of local recurrence (four out of six lesions) in patients with tumor extension into the soft tissue raises some concerns. It should be noted, however, that one local recurrence was in a patient treated with cryosurgery following a pathologic fracture, one involved a sacral lesion, and one involved a massive pelvic lesion in a patient with multiple comorbidities. Although there were two posttraumatic fractures, these seem to be unrelated to the surgery since they did not occur at the operative site and were following a motor vehicle accident and a fall. The effect that cryosurgery may have had on these fractures is unknown and warrants further investigation, especially since other physical adjuvants such as phenol have shown similarly low rates of local recurrence following extended curettage in the treatment of low-grade chondrosarcoma.
The authors have demonstrated that a “low-grade cartilage tumor with evidence of aggressive behavior (pain, progressive enlargement, and/or endosteal scalloping involving more than two-thirds of the cortical thickness)” can be treated safely with intralesional surgery, with acceptable local control and excellent functional outcomes, and does not require wide resection. The fact that there were no cases of distant metastasis even with the inclusion of those lesions with soft-tissue extension further supports the authors’ conclusion advocating against wide resection. This will by no means be the final word. Questions still remain as to the appropriateness of intralesional procedures for those “low-grade” tumors with soft-tissue extension beyond the cortex, which had a high local recurrence rate. Similarly, the optimal physical adjuvant, whether liquid nitrogen or phenol, remains unknown. The authors are to be congratulated for providing clarity and consistency regarding the term “low-grade chondrosarcoma” and for further defining the role of intralesional surgery for these tumors.