Peter C. Ferguson

Myxoid\Round Cell Liposarcoma (MRCLS) Revisited: An Analysis of 418 Primarily Managed Cases

BackgroundObjectives of this study were to evaluate oncologic outcomes and to provide guidelines for the management of primary myxoid (MLS) and round cell liposarcoma (RCLS).MethodsA multicenter, retrospective study of 418 cases of MRCLS primarily managed by Canadian multidisciplinary sarcoma teams.ResultsStudy included 418 cases (MLS: 311 patients and RCLS: 107;xa0>xa05% round cell) with a median age of 45xa0years and a median follow-up of 5.2xa0years. Median tumor size was 10xa0cm, and 81% were deep and 90% were in lower limb. The majority of patients underwent surgical resection and radiotherapy, with a small percentage (6%) receiving chemotherapy. The overall 10-year local control rate was 93% with no differences between MLS and RCLS. Radiotherapy was significant in preventing local relapse and reducing tumor diameter (medianxa0=xa018%) and improving microscopic margin status, but did not impact survival. Radiotherapy and the margin status were independent predictors of local recurrence. The 5- and 10-year metastatic-free survivals were 84 and 77% respectively for MLS and 69 and 46% for RCLS. The initial site of metastasis was found in multiple locations (34%) and bone involvement was frequent (40%) with predilection for spine (79%). Round cell percent (>xa05%) and tumor diameter (>xa010xa0cm) correlated with increased risk for metastasis and death.ConclusionsMLS and RCLS showed different metastatic risk but equally good local control. Radiotherapy was effective in preventing local recurrence and should be delivered as neoadjuvant. New staging strategies are to be defined to account for the unusual metastatic pattern.

The effect of surgical synovectomy and radiotherapy on the rate of recurrence of pigmented villonodular synovitis of the knee: an individual patient meta-analysis

Pigmented villonodular synovitis (PVNS) is a rare proliferative process of the synovium which most commonly affects the knee and occurs in either a localised (LPVNS) or a diffuse form (DPVNS). The effect of different methods of surgical synovectomy and adjuvant radiotherapy on the rate of recurrence is unclear. We conducted a systematic review and identified 35 observational studies in English which reported the use of surgical synovectomy to treat PVNS of the knee. A meta-analysis included 630 patients, 137 (21.8%) of whom had a recurrence after synovectomy. For patients with DPVNS, low-quality evidence found that the rate of recurrence was reduced by both open synovectomy (odds ration (OR) = 0.47; 95% CI 0.25 to 0.90; p = 0.024) and combined open and arthroscopic synovectomy (OR = 0.19, 95% CI = 0.06 to 0.58; p = 0.003) compared with arthroscopic surgery. Very low-quality evidence found that the rate of recurrence of DPVNS was reduced by peri-operative radiotherapy (OR = 0.31, 95% CI 0.14 to 0.70; p = 0.01). Very low-quality evidence suggested that the rate of recurrence of LPVNS was not related to the surgical approach. This meta-analysis suggests that open synovectomy or synovectomy combined with peri-operative radiotherapy for DPVNS is associated with a reduced rate of recurrence. Large long-term prospective multicentre observational studies, with a focus on both rate of recurrence and function, are required to confirm these findings.

Fixation of pathological humeral fractures by the cemented plate technique

Pathological fractures of the humerus are associated with pain, morbidity, loss of function and a diminished quality of life. We report our experience of stabilising these fractures using polymethylmethacrylate and non-locking plates. We undertook a retrospective review over 20 years of patients treated at a tertiary musculoskeletal oncology centre. Those who had undergone surgery for an impending or completed pathological humeral fracture with a diagnosis of metastatic disease or myeloma were identified from our database. There were 63 patients (43 men, 20 women) in the series with a mean age of 63 years (39 to 87). All had undergone intralesional curettage of the tumour followed by fixation with intramedullary polymethylmethacrylate and plating. Complications occurred in 14 patients (22.2%) and seven (11.1%) required re-operation. At the latest follow-up, 47 patients (74.6%) were deceased and 16 (25.4%) were living with a mean follow-up of 75 months (1 to 184). A total of 54 (86%) patients had no or mild pain and 50 (80%) required no or minimal assistance with activities of daily living. Of the 16 living patients none had pain and all could perform activities of daily living without assistance. Intralesional resection of the tumour, filling of the cavity with cement, and plate stabilisation of the pathological fracture gives immediate rigidity and allows an early return of function without the need for bony union. The patients local disease burden is reduced, which may alleviate tumour-related pain and slow the progression of the disease. The cemented-plate technique provides a reliable option for the treatment of pathological fractures of the humerus.

Peripheral Nerve Considerations in the Management of Extremity Soft Tissue Sarcomas

Evaluation of peripheral nerves, both clinically and with imaging, is critical in the evaluation of patients with extremity soft tissue sarcomas. If an essential peripheral nerve is felt to be adjacent to a soft tissue sarcoma but not circumferentially surrounded, it can usually be salvaged using the technique of epineural dissection in the setting of adjuvant radiation. If, however, a critical nerve is circumferentially involved with tumor, it must be sacrificed for the sake of local control. Various reconstruction techniques are available in this situation, including nerve grafting, distal nerve transfer, and tendon transfer, with each technique having specific indications. Regardless of the technique, it is important to inform the patient that normal extremity function is not likely to be achieved. The issue of nerve involvement therefore becomes a critical factor in determining the possibility of limb salvage in borderline cases. For the situation in which postoperative function is already expected to be compromised due to vascular, bone, or extensive soft tissue resection, nerve resection may be the ultimate deciding factor in recommending amputation rather than limb salvage.

Monitoring the Adequacy of Surgical Margins After Resection of Bone and Soft-Tissue Sarcoma

PurposeLocal recurrence of a bone or soft-tissue sarcoma is a devastating complication. Minimizing the proportion of positive surgical margins, or tumor contamination, during resection is of paramount importance.MethodsResections of sarcomas were prospectively evaluated and considered inadequate if unplanned microscopic or macroscopic positive surgical margins were identified or if inadvertent tumor contamination of the wound occurred. Monitoring of performance was continuously performed with a statistical process control method, the cumulative sum test, and regular meetings were held to discuss the reasons for failures. A target performance of 5xa0% inadequate procedures was chosen.ResultsA total of 146 sarcomas—106 soft tissue and 40 bone—were resected during the monitoring period. Six (4xa0%) procedures were considered inadequate: three patients had inadvertent tumor contamination of the wound, two patients had unplanned microscopic positive margins, and one patient had both. Performance was considered to be adequate during the whole monitoring period.ConclusionsWith adequate preoperative planning and surgical technique, the risk of an inadequate resection can be limited. Implementation of a statistical process control method allows for ongoing performance monitoring and ensures that quality remains adequate over time.

Effects of Neoadjuvant Chemotherapy on Image-Directed Planning of Surgical Resection for Distal Femoral Osteosarcoma

BACKGROUNDnStandard therapy for localized osteosarcoma includes neoadjuvant chemotherapy preceding local control surgery, followed by adjuvant chemotherapy. When limb-salvage procedures were being developed, preoperative chemotherapy allowed a delay in definitive surgery to permit fabrication of custom endoprosthetic reconstruction implants. One rationale for its continuation as the care standard has been the perception that it renders surgery easier and safer. Our objective was to compare surgical procedures planned on the basis of magnetic resonance images (MRIs) of distal femoral osteosarcomas acquired before neoadjuvant chemotherapy with surgical procedures planned on the basis of MRIs acquired after neoadjuvant chemotherapy as a measure of the surgically critical anatomic effects of the chemotherapy.nnnMETHODSnTwenty-four consecutive patients with distal femoral osteosarcoma had available digital MRIs preceding and following neoadjuvant chemotherapy. Thorough questionnaires were used to catalogue surgically critical anatomic details of MRI-directed surgical planning. Four faculty musculoskeletal oncologic surgeons and two musculoskeletal radiologists evaluated the blinded and randomly ordered MRIs. Interrater and intrarater reliabilities were calculated with intraclass correlation coefficients. The Student t test and chi-square test were used to compare pre-chemotherapy and post-chemotherapy continuous and categorical variables on the questionnaire. Mixed-effect regression models were employed to compare surgical procedures planned on the basis of pre-chemotherapy MRIs and with those planned on the basis of post-chemotherapy MRIs.nnnRESULTSnThe blinded reviews generated strong intraclass correlation coefficients for both interrater (0.772) and mean intrarater (0.778) reliability. The MRI-planned resections for the majority of tumors changed meaningfully after chemotherapy, but in inconsistent directions. On the basis of mixed-effect regression modeling, it appeared that more amputations were planned on the basis of post-chemotherapy MRIs. No other parameters differed in a significant and clinically meaningful fashion. Surgeons demonstrated their expectation that neoadjuvant chemotherapy would improve resectability by planning more radical surgical procedures on the basis of scans that they predicted had been obtained pre-chemotherapy.nnnCONCLUSIONSnSurgeons can reliably record the anatomic details of a planned resection of an osteosarcoma. Such methods may be useful in future multi-institutional clinical trials or registries. The common belief that neoadjuvant chemotherapy increases the resectability of extremity osteosarcomas remains anecdotally based. Rigorous assessment of this phenomenon in larger cohorts and at other anatomic sites as well as re-evaluation of other arguments for neoadjuvant chemotherapy should be considered.

Navigated Pelvic Osteotomy and Tumor Resection A Study Assessing the Accuracy and Reproducibility of Resection Planes in Sawbones and Cadavers

BACKGROUNDnThis Sawbones and cadaver study was performed to assess the accuracy and reproducibility of pelvic bone cuts made with use of a novel navigation system with a navigated osteotome and oscillating saw.nnnMETHODSnUsing a novel navigation system and a three-dimensional planning tool, we navigated pelvic bone cuts that were representative of typical cuts made in pelvic tumor resections. The system includes a prototype mobile C-arm for intraoperative cone-beam computed tomography, real-time optical tracking (Polaris), and three-dimensional visualization software. Three-dimensional virtual radiographs were utilized in addition to triplanar (axial, sagittal, and coronal) navigation. In part one of the study, we navigated twenty-four sacral bone cuts in Sawbones models and validated our results in sixteen similar cuts in cadavers. In part two, we developed three Sawbones models of pelvic tumors based on actual patient scenarios and compared three navigated resections with three non-navigated resections for each tumor model. Part three assessed the accuracy of the system with multiple users.nnnRESULTSnThere were ninety navigated cuts in Sawbones that were compared with fifty-four non-navigated cuts. In the navigated Sawbones cuts, the mean entry and exit cuts were 1.4 ± 1 mm and 1.9 ± 1.2 mm from the planned cuts, respectively. In comparison, the entry and exit cuts in Sawbones that were not navigated were 2.8 ± 4.9 mm and 3.5 ± 4.6 mm away from the planned osteotomy site. The navigated cuts were significantly more accurate (p ≤ 0.01). In the cadaver study, navigated entry and exit cuts were 1.5 ± 0.9 mm and 2.1 ± 1.5 mm from the planned cuts. The variation among three different users was 1 mm on both the entry and exit cuts.nnnCONCLUSIONSnNavigation to guide pelvic bone cuts is accurate and feasible. Three-dimensional radiographs should be used for improved accuracy. Navigated cuts were significantly more accurate than non-navigated cuts were. A margin of 5 mm between the target tumor volume and the planned cut plane would result in a negative margin resection in more than 95% of the cuts.nnnCLINICAL RELEVANCEnThe accuracy of pelvic bone tumor resections and pelvic osteotomies can be improved with navigation to within 5 mm of the planned cut.

Using the CUSUM Test to Control the Proportion of Inadequate Open Biopsies of Musculoskeletal Tumors

BackgroundBiopsies of musculoskeletal tumors lead to alterations in treatment in almost 20% of cases. Control charts are useful to ensure that a process is operating at a predetermined level of performance, although their use has not been demonstrated in assessing the adequacy of musculoskeletal biopsies.Questions/purposesWe therefore (1) assessed the incidence of and the reasons for inadequate musculoskeletal biopsies when following guidelines for performing the procedure; and (2) implemented a process control chart, the CUSUM test, to monitor the proportion of inadequate biopsies.MethodsWe prospectively studied 116 incisional biopsies. The biopsy was performed according to 10 rules to (1) minimize contamination in the tissues surrounding the tumor; and (2) improve accuracy. A frozen section was systematically performed to confirm that a representative specimen was obtained. Procedures were considered inadequate if: (1) another biopsy was necessary; (2) the biopsy tract was not appropriately placed; and (3) the treatment provided based on the diagnosis from the biopsy was not appropriate.ResultsFive (4.3%) of the 116 incisional biopsy procedures were considered failures. Three patients required a second repeat open biopsy and two were considered to receive inappropriate treatment. No alarm was raised by the control chart and the performance was deemed adequate over the monitoring period.ConclusionsThe proportion of inadequate musculoskeletal open biopsies performed at a referral center was low. Using a statistical process control method to monitor the failures provided a continuous measure of the performance.

Does the method of treatment affect the outcome in soft-tissue sarcomas of the adductor compartment?

We have investigated the significance of the method of treatment on the oncological and functional outcomes and on the complications in 184 patients with soft-tissue sarcomas of the adductor compartment managed at three international centres. The overall survival at five years was 65% and was related to the grade at diagnosis and the size of the tumour. There was no difference in overall survival between the three centres. There was, however, a significant difference in local control with a rate of 28% in Centre 1 compared with 10% in Centre 2 and 5% in Centre 3. The overall mean functional score using the Toronto Extremity Salvage Score in 70 patients was 77% but was significantly worse in patients with wound complications or high-grade tumours. The scores were not affected by the timing of radiotherapy or the use of muscle flaps. This large series of soft-tissue sarcomas of the adductor compartment has shown that factors influencing survival do not vary across the international boundaries studied, but that methods of treatment affect complications, local recurrence and function.

Internal fixation of radiation-induced pathological fractures of the femur has a high rate of failure

We investigated the clinical outcome of internal fixation for pathological fracture of the femur after primary excision of a soft-tissue sarcoma that had been treated with adjuvant radiotherapy. A review of our database identified 22 radiation-induced fractures of the femur in 22 patients (seven men, 15 women). We noted the mechanism of injury, fracture pattern and any complications after internal fixation, including nonunion, hardware failure, secondary fracture or deep infection. The mean age of the patients at primary excision of the tumour was 58.3 years (39 to 86). The mean time from primary excision to fracture was 73.2 months (2 to 195). The mean follow-up after fracture fixation was 65.9 months (12 to 205). Complications occurred in 19 patients (86%). Nonunion developed in 18 patients (82%), of whom 11 had a radiological nonunion at 12 months, five a nonunion and hardware failure and two an infected nonunion. One patient developed a second radiation-associated fracture of the femur after internal fixation and union of the initial fracture. A total of 13 patients (59%) underwent 24 revision operations. Internal fixation of a pathological fracture of the femur after radiotherapy for a soft-tissue sarcoma has an extremely high rate of complication and requires specialist attention.