Osteosarcoma: angiographic assessment of response to preoperative chemotherapy

Location of residual viable tumor cells after neoadjuvant chemotherapy: A new concept with high prognostic performance in osteosarcoma

BACKGROUND AND OBJECTIVES

The purpose of this study was to establish a new concept for evaluating responses to neoadjuvant chemotherapy in osteosarcoma.

METHODS

A total of 56 high-grade extremity osteosarcoma patients were retrospectively reviewed. A new conceptual method was derived from locations of residual viable tumor cells (LRVTC) after chemotherapy, whether extracompartmental or intracompartmental, rather than quantitative measurements of necrosis rates of tumor cells.

RESULTS

LRVTC after chemotherapy was independently associated with overall survival ([OS]hazard ratio [HR] = 6.502, P = 0.008) after adjustment for Huvos grade (HR = 3.694, P = 0.045), alkaline phosphatase ([ALP] HR = 2.140, P = 0.226), size (HR = 0.318, P = 0.133), joint extension (HR = 2.309, P = 0.162), and metastasis at diagnosis (HR = 8.228, P = 0.009). LRVTC was also independently associated with metastasis (HR = 5.096, P = 0.002) after adjustment for Huvos grade (HR = 2.261, P = 0.101), ALP (HR = 2.558, P = 0.053), size (HR = 1.280, P = 0.641), and joint extension (HR = 1.800, P = 0.254). AUC values of LRVTC for OS and metastasis were superior to those of Huvos grade: AUCs for OS (LRVTC: 0.757, Confidence Interval [CI] = 0.618 to 0.865 vs Huvos grade: 0.590, [CI] = 0.445 to 0.725; AUC = 0.167, P = 0.086) and metastasis (LRVTC: 0.769, CI = 0.631 to 0.874 vs Huvos grade: 0.606, [CI] = 0.461 to 0.739; AUC = 0.163, P = 0.046).

CONCLUSIONS

LRVTC after chemotherapy may be useful as a new method with high performance for evaluating chemo-responses in osteosarcoma.

Evaluation of static and dynamic MRI for assessing response of bone sarcomas to preoperative chemotherapy: Correlation with histological necrosis

OBJECTIVES

Preoperative chemotherapy plays a key role in management of bone sarcomas. Postoperative evaluation of histological necrosis has been the gold standard method of assessing response to preoperative chemotherapy. This study was done to evaluate the efficacy of static and dynamic magnetic resonance imaging (MRI) for assessing response preoperatively.

MATERIALS AND METHODS

Our study included 14 patients (12 osteosarcomas and 2 malignant fibrous histiocytomas) with mean age of 21.8 years, treated with preoperative chemotherapy followed by surgery. They were evaluated with static and dynamic MRI twice, before starting chemotherapy and again prior to surgery. Change in tumor volume and slope of signal intensity - time curve were calculated and correlated with percentage of histological necrosis using Pearson correlation test.

RESULTS

The change in dynamic MRI slope was significant (P = 0.001). Also, ≥60% reduction in slope of the curve proved to be an indicator of good histological response [positive predictive value (PPV) =80%]. Change in tumor volume failed to show significant correlation (P = 0.071). Although it showed high negative predictive value (NPV = 85.7%), PPV was too low (PPV = 57.14%).

CONCLUSIONS

Dynamic MRI correctly predicts histological necrosis after administration of preoperative chemotherapy to bone sarcomas. Hence, it can be used as a preoperative indicator of response to neoadjuvant chemotherapy. On the other hand, volumetric assessment by static MRI is not an effective predictor of histological necrosis. This study proves the superiority of dynamic contrast-enhanced study over volumetric study by MRI.

Transcatheter intra-arterial limb infusion for extremity osteosarcoma: technical considerations and outcomes

The goal of transcatheter arterial infusion is to achieve better tumor response by delivering chemotherapy directly into the arterial bed supplying a neoplasm. The rationale behind such therapy relies on the potentially increased tumoricidal effect afforded by higher local concentrations of the infused chemotherapic agent(s) combined with longer tissue exposure times. The use of intra-arterial chemotherapy with or without transcatheter embolization before limb salvage surgery has been demonstrated to induce substantial tumor necrosis and reduce intraoperative blood loss. Recent advances in catheter technology have greatly reduced the morbidity associated with the procedure. This article will focus on the technical aspects of intra-arterial chemotherapy for the treatment of extremity osteosarcoma.

Histopathologic and Radiologic Assessment of Chemotherapeutic Response in Ewing's Sarcoma: A Review

Ewing's sarcoma is a highly malignant tumor that metastasizes rapidly and is thus associated with a low survival rate. The intensification of chemotherapy has been shown to improve the overall survival of patients with Ewing's sarcoma. However, intensified chemotherapy can lead to increased toxicity or even the development of secondary malignancies. The stratification of patients with Ewing's sarcoma into “good” and “poor” responders may help guide the administration of progressively more intensified chemotherapy. Thus, an accurate assessment of the chemotherapeutic response, as well as the extent of chemotherapy-induced tumor necrosis, is critical for avoiding potential treatment-related complications in these patients. This paper reviews the methods currently used to evaluate chemotherapeutic response in Ewing's sarcoma, focusing specifically on histopathologic and imaging analyses, and discusses novel therapies and imaging methods that may help improve the overall survival of these patients.

Diffusion-weighted MR imaging in musculoskeletal radiology: applications in trauma, tumors, and inflammation

Diffusion-weighted imaging is a noninvasive magnetic resonance technique that is capable of measuring icroscopic movement of water molecules (ie, random or Brownian motion) within biologic tissues. Diffusion weighting is achieved with a pulsed-field gradient that leaves "static" spins unaffected but causes dephasing of spin ensembles that experience different motion histories according to their diffusion paths, with respect to the direction of the gradient. This article focuses on the interesting opportunities of the use of diffusion weighted imaging in the diagnosis of musculoskeletal diseases, including trauma, tumor, and inflammation.

Osteosarcoma multidisciplinary approach to the management from the pathologist's perspective

Osteosarcoma is a primary malignant tumor of the bone in which proliferating neoplastic cells produce osteoid and/or bone, if only in small amounts. This histological principle defines a tumor that usually affects young males more frequently than females, and disproportionately involves the long bones of the appendicular skeleton. These tumors are generally locally aggressive and tend to produce early, lethal systemic metastases. However, osteosarcoma is not a single disease but a family of neoplasms, sharing the single histological finding of osseous matrix production in association with malignant cells. The majority (i.e., 75%) of cases are relatively stereotypical from the demographic, clinical, radiographic and histologic points of view. These tumors generally occur in the metaphyseal portion of the medullary cavity of the long bone and are referred to as "Conventional Osteosarcoma." The group is sub classified by the form of the dominant matrix present within the tumor, which may be bone, cartilage or fibrous tissue, and it is correspondingly referred to as osteoblastic, chondroblastic and fibroblastic osteosarcoma. The remaining 25% of cases have unique parameters that allow reproducible identification of tumors which are biologically different from conventional osteosarcoma and are referred to as "Variants." The parameters identifying Variants fall into one of three major groups: (1) clinical factors, (2) histologic findings and (3) location of origin--within or on the cortex. Because of their inherent biological difference from Conventional Osteosarcoma, the Variants identify cases which must be excluded from analysis of data pertaining to the treatment of the majority of cases: Conventional Osteosarcoma. The diagnostic parameters of osteosarcoma must be sufficiently inclusive to identify all the members of this potentially lethal tumor. Conversely, criteria for sub classification must be restricted to assure homogenous populations of tumors productively incorporating different biological behavior and the potential for development of unique treatment strategies which are different from those for Conventional Osteosarcoma. This can be designated "Classification Based Therapy" or "Therapy Based Osteosarcoma." With this background, we will discuss the highly disciplined approach to the management of osteosarcoma from the pathologist's perspective. Factors governing the assessment of the response to preoperative chemotherapy will also be reviewed.

Imaging assessment of osteosarcoma in childhood and adolescence: diagnosis, staging, and evaluating response to chemotherapy

Osteosarcoma is an aggressive tumor of mesenchymal origin, capable of producing osteoid and immature bone. It is the most frequent primary malignant skeletal neoplasm in children and adolescents. Imaging studies play a major role in initial diagnosis, staging, and assessment of tumor response to chemotherapy. Conventional radiography is the prime imaging modality for diagnosis of bony tumors. Radionuclide bone scan is used in detection of metastatic lesions in the other bones. Computed tomography may be used as an adjunct to conventional radiography, but its main role is detection of pulmonary metastasis. The standard magnetic resonance imaging is the most specific modality for local staging and monitoring response to chemotherapy, and distinguishing postsurgical changes from residual tumor. Dynamic contrast-enhanced magnetic resonance imaging has been introduced to quantify the percentage of tumor necrosis, identify early responders, and thus predict survival. The role of 18F fluorodeoxyglucose positron emission tomography (PET) in the staging and management of osteosarcoma is evolving. It has the advantage of total body imaging and may have an overall role in tumor staging and grading, detection of early response, and therefore, in the prognosis and detection of recurrence.

Osteosarcoma: review of the past, impact on the future. The American experience

Major advances have been achieved in the treatment of osteosarcoma with the discovery of several chemotherapeutic agents that were active in the disease. These agents comprise high-dose methotrexate with leucovorin rescue, Adriamycin, cisplatin, ifosfamide and cyclophosphamide. The agents were integrated into various regimens and administered in an effort to destroy silent pulmonary micrometastases which are considered to be present in at least 80% of patients at the time of diagnosis. Their efficacy in achieving this goal was realized and their use was further extended to the application of preoperative (neoadjuvant) chemotherapy to destroy the primary tumor and achieve safe surgical resections. Disease free survival was escalated from <20% prior to the introduction of effective chemotherapy to 55-75% and overall survival to 85%. Further, the opportunity to perform limb salvage was expanded to 80% of patients. Of interest also was an attempt in one series to treat the primary tumor exclusively with chemotherapy, and abrogation of surgery. Adding to these advances, varieties of subsequently discovered agents are currently undergoing investigations in patients who have relapsed and/or failed conventional therapy. The agents include Gemcitabine, Docetaxel, novel antifolate compounds, and a liposome formulation of adriamycin (Doxil). A biological agent, muramyl tripeptide phosphatidyl ethanolamine (MTPPE) was also recently investigated in a 2x2 factorial design to determine its efficacy in combination with chemotherapy (methotrexate, cisplatin, Adriamycin and ifosfamide).In circumstances where the tumor was considered inoperable, chemotherapy and radiotherapy were advocated for local control. High dose methotrexate, Adriamycin and cisplatin and Gemcitabine interact with radiation therapy and potentiate its therapeutic effect. This combination is also particularly useful in palliation. Occasionally, the combination of radiation and chemotherapy may render a tumor suitable for surgical ablation. Samarium153, a radio active agent, is also used as palliative therapy for bone metastases.However, despite the advances achieved with the multidisciplinary application of chemotherapy, radiotherapy and surgical ablation of the primary tumor over the past 3(1/2) decades, the improved cure rate reported initially has not altered. Particularly vexing is the problem of rescuing patients who develop pulmonary metastases after receiving seemingly effective multidisciplinary treatment. Approximately 15-25% of such patients only are rendered free of disease with the reintroduction of chemotherapy and resection of metastases. Extrapulmonary metastases and multifocal osteosarcoma also constitute a major problem. The arsenal of available agents to treat such patients has not made any substantial impact in improving their survival. New chemotherapeutic agents are urgently required to improve treatment and outcome. Additional strategies to be considered are targeted tumor therapy, anti tumor angiogenesis, biotherapy and therapy based upon molecular profiles. This communication outlines sequential discoveries in the chemotherapeutic research of osteosarcoma in the United States of America. It also describes the principles regulating the therapeutic application of the regimens and considers the impact of their results on the conduct in the design of future investigations and treatment.

Intraarterial chemotherapy for extremity osteosarcoma and MFH in adults

The neoadjuvant treatment of osteosarcoma using intravenous agents has resulted in survival rates of 55% to 77% [3, 5, 6, 20, 22, 35]. We designed a neoadjuvant chemotherapy protocol using combined intraarterial and intravenous agents to treat high-grade osteosarcoma and malignant fibrous histiocytoma of bone in an attempt to improve survival. We report the results of treating 53 adults (age 18-77 years) diagnosed with nonmetastatic extremity osteosarcoma or malignant fibrous histiocytoma. Preoperative chemotherapy consisted of intravenous doxorubicin followed by intraarterial cisplatinum administered repetitively every 3 weeks for three to five cycles, depending on tumor response assessed by serial arteriography. Dose and duration of cisplatin were adjusted for tumor size. After resection, good responders (90% or greater necrosis) underwent treatment with the same agents and poor responders were treated with alternative agents for longer duration. Minimum followup was 24 months (mean, 111 months; range, 24-235 months). Estimated Kaplan-Meier survival at 10 years was 82% and event-free survival was 79%. Forty-one patients (77%) had a good histologic response and 92% (49 of 53) underwent limb-sparing procedures. Local recurrence occurred in two patients (4%). These results compared favorably with those reported in the current literature.

LEVEL OF EVIDENCE

Level III, therapeutic study. See the Guidelines for Authors for a complete description of levels of evidence.

Monitoring therapeutic responses of primary bone tumors by diffusion-weighted image: Initial results

The purpose of our study was to investigate whether quantitative diffusion-weighted images (DWI) were useful for monitoring the therapeutic response of primary bone tumors. We encountered 18 osteogenic and Ewing sarcomas. Magnetic resonance (MR) images were performed in all patients before and after therapy. We measured the apparent diffusion coefficient (ADC) values, contrast-to-noise ratio (CNR), and tumor volume of the bone tumors pre- and posttreatment. We determined change in ADC value, change in CNR on T2-weighted images (T2WI), change in CNR on gadopentetate dimeglumine (Gd)-T1-weighted images (Gd-T1WI), and change in tumor volume. The bone tumors were divided into two groups: group A was comprised of tumors with less than 90% necrosis after treatment and group B of tumors at least with 90%. Changes in ADC value, tumor volume, and CNR were compared between the groups. Change in the ADC value was statistically greater in group B than that in the group A (p = 0.003). There was no significant difference in the changes in CNR on T2WI (p = 0.683), in CNR on Gd-T1WI (p = 0.763), and tumor volume (p = 0.065). The ADC value on DWI is a promising tool for monitoring the therapeutic response of primary bone sarcomas.

Improved survival in primary nonmetastatic pediatric osteosarcoma of the extremity

A prospective study using a dose-intensified neoadjuvant intra-arterial chemotherapy regimen was designed to improve survival rates of young patients with primary, nonmetastatic osteosarcoma of the extremity. Arteriography was implemented to individualize duration of therapy by serially assessing change in tumor neovascularity. Intravenous doxorubicin and intra-arterial cisplatin were administered repetitively at 3-week intervals until > or = 90% reduction in tumor neovascularity was achieved. Surgery was delayed until this good arteriographic response was documented. After resection, prediction of tumor neovascularity was compared with tumor necrosis. Since 1987, 62 eligible patients younger than 22 years old were treated with an average of four neoadjuvant courses. Toxicities were manageable. Fifty-four (87%) patients had a good histologic response. The rate of limb preservation surgery was 93.5% (58/62). Accuracy and sensitivity of serial arteriography in predicting histologic response were 92% and 98% respectively, and greatly assisted surgical planning. With an average followup of 91 months, estimated Kaplan-Meier survival at 10 years was 93% and event-free survival was 86%. Osteosarcoma survival rates were significantly improved by the use of this regimen compared with previously reported results. Serial arteriography succeeded in individualizing duration of neoadjuvant therapy and led to a higher rate of good histologic response.

LEVEL OF EVIDENCE

Therapeutic study, level II-1 (prospective cohort study). See the Guidelines for Authors for a complete description of levels of evidence.

The Value of Serial Arteriography in Osteosarcoma: Delivery of Chemotherapy, Determination of Therapy Duration, and Prediction of Necrosis

PURPOSE

To investigate the value of serial arteriography to assess tumor response, predict necrosis, and individualize the duration of a combined intravenous (IV) and intraarterial (IA) neoadjuvant chemotherapy protocol in patients with biopsy-proven high-grade osteosarcoma or malignant fibrohistiocytoma of bone.

MATERIALS AND METHODS

Between July 1987 and March 2003, 109 patients completed a chemotherapy protocol of neoadjuvant IV doxorubicin and IA cisplatin. Patients were eligible regardless of age, disease stage, or disease site. A minimum of three IA cycles followed by definitive surgery was required for inclusion in the final analysis. IA dose and duration were increased for tumors larger than 10 cm. Initial arteriograms were scored as indicating mild, moderate, or marked tumor neovascularity (TNV). Subsequent arteriograms were prospectively compared with the baseline image for percent change in TNV. Treatment continued until a maximum of five cycles were administered or one of three criteria were met: (i) at least 90% decrease in TNV, (ii) plateau of effect, or (iii) no response.

RESULTS

Of 408 IA procedures, 42 patients underwent three cycles, 53 underwent four, and 14 required five cycles of neoadjuvant therapy. There was a 2.5% minor complication rate. Eighty-six percent of patients exhibited at least 90% decrease in TNV and 82% exhibited good histologic response (> or =90% tumor necrosis). Serial arteriography predicted a good histologic response with an accuracy of 90% and a sensitivity of 97%.

CONCLUSIONS

Serial arteriography was highly sensitive and accurately predicted good responses. This individually modified, dose-intensified neoadjuvant protocol yielded an excellent histologic response rate with minimal complications. Future endeavors should involve a multiinstitutional study of this unique approach.

Dynamic contrast-enhanced MR imaging in monitoring response to isolated limb perfusion in high-grade soft tissue sarcoma: initial results

The objective of this study was to evaluate whether dynamic contrast-enhanced MR imaging can determine tumor response and localize residual viable tumor after isolated limb perfusion (ILP) chemotherapy in soft tissue tumors. Twelve consecutive patients, with histologically proven high-grade soft tissue sarcoma, prospectively underwent non-enhanced MR and dynamic contrast-enhanced MR imaging before and after ILP. Tumor volume was measured on non-enhanced MR images. The temporal change of signal intensity in a region of interest on dynamic contrast-enhanced MR images was plotted against time. Start, pattern, and progression of enhancement were recorded. Histopathologic response was defined as complete response if no residual viable tumor was present, partial remission if <50% viable tumor was present, and no change if > or =50% viable tumor was present in the resection specimen. Resected specimens for correlation with histopathology were available for 10 patients; 5 patients had partial remission and 5 had no change. Volume measurements correctly predicted tumor response in 6 of 10 patients. Dynamic contrast-enhanced MR correctly predicted tumor response in 8 of 10 patients. Early rapidly progressive enhancement correlated histologically with residual viable tumor. Late and gradual, or absence of enhancement, was associated with necrosis, predominantly centrally located, or granulation tissue. These preliminary results show that dynamic contrast-enhanced MR imaging offers potential for non-invasive monitoring of response to isolated limb perfusion in soft tissue sarcomas due to identification of residual areas of viable tumor and subsequently may provide clinically useful information with regards to timing and planning of additional surgery. Further prospective studies in a larger patient population is warranted.

Superior survival in treatment of primary nonmetastatic pediatric osteosarcoma of the extremity

BACKGROUND

A protocol to treat osteosarcoma of the extremity was developed at two local institutions.

METHODS

The study involved a dose-intensified neoadjuvant protocol of intravenous doxorubicin and intra-arterial cisplatin administered repetitively until maximum angiographic response was noted. Definitive surgery was delayed until > or =90% reduction in tumor neovascularity was documented. Prospective assessment of serial arteriograms was highly accurate (94%) in predicting histological response and assisted in surgical planning. After resection, if patients were determined to be good responders (> or =90% tumor necrosis), they underwent a 4-month postoperative course with the same agents. Poor responders (<90% necrosis) were treated with alternative agents for 12 months from diagnosis. Forty-seven assessable patients with primary, high-grade, nonmetastatic osteosarcoma of the extremity were included in this analysis. The median age was 15 years (range, 7-21 years).

RESULTS

Patients underwent an average of four preoperative intra-arterial courses. Forty-three patients underwent limb-preservation procedures, and 41 had >90% tumor necrosis. With an average follow-up of 92 months (range, 20-178 months), 39 patients were continuously disease free, 3 died of disease, 1 died of other causes, and 4 have no evidence of disease 11 to 51 months after relapse (all pulmonary metastases). There were no local recurrences. Kaplan-Meier analysis demonstrated a 10-year overall survival of 92% and an event-free survival of 84%.

CONCLUSIONS

This study demonstrates excellent survival with a dose-intensified neoadjuvant protocol. Future endeavors should involve a multi-institutional randomized study comparing this approach with another multiagent intravenous neoadjuvant protocol.

Current treatment of osteosarcoma

A comprehensive multidisciplinary approach has transformed osteosarcoma from a disease with a modest long-term survival to one in which at least two-thirds of patients will be cured. Surgery remains the vital modality for treating the primary tumor, whereas adjuvant chemotherapy plays an essential role in the control of subclinical metastatic disease. Complete surgical excision of the primary tumor remains an essential element of treatment. For many patients, a combination of advances in surgical technique, improved imaging modalities to accurately document tumor extent, and the effect of neoadjuvant chemotherapy has made limb salvage procedures a safe alternative to amputation. In some patients for whom complete surgical excision is impossible, the addition of radiation therapy may allow local tumor control. The most effective chemotherapy agents currently in use include high-dose methotrexate, doxorubicin, cisplatin, and ifosfamide/etoposide. The optimal schedule of therapy is still being investigated, as is the role of dose intensification. Unfortunately, some groups of patients remain at high risk of eventual relapse. Those whose tumors show relatively low degrees of necrosis after administration of chemotherapy have poorer survival than patients with more chemotherapy-responsive tumors. Similarly, patients who present with overt metastatic disease (particularly bone metastases), as well as patients with tumors that recur after treatment, continue to have an unsatisfactory outcome. These groups, in particular, may benefit from future investigations into novel agents, such as biological response modifiers, antiangiogenesis factors, and growth receptor modulation.

Imaging in skeletal paediatric oncology

The prognosis for the child presenting with a bone sarcoma has improved dramatically with the introduction of adjuvent chemotherapy. As a result the majority of patients can now expect to undergo limb salvage surgery. The role of imaging in the management of the child presenting with a suspected sarcoma is presented. This commences with tumour detection, through diagnosis and surgical staging, re-staging with assessment of response to chemotherapy and follow-up surveillance for the development of local recurrence and/or metastases. The importance of the multidisciplinary approach to the management of bone sarcomas is emphasised.

Imaging assessment of the responses of osteosarcoma patients to preoperative chemotherapy: angiography compared with thallium-201 scintigraphy

BACKGROUND

Assessment of the responses of osteosarcoma patients to preoperative chemotherapy is of clinical importance. The purpose of this study was to estimate the accuracy of angiography and thallium-201 scintigraphy, compared with histology, in assessing the responses of patients with osteosarcoma to preoperative chemotherapy.

METHODS

Nineteen patients with osteosarcoma who were diagnosed between 1992 and 1997 were studied. The findings of angiography and thallium-201 scintigraphy before and after preoperative chemotherapy were compared with the percentage of necrosis of tumor cells and the response grade as determined histologically. Quantitative analysis of the isotopic uptake by thallium-201 scintigraphy before and after chemotherapy, defined as the alteration ratio, was correlated with the percentage of tumor necrosis.

RESULTS

Angiography yielded a sensitivity of 88%, a specificity of 73%, and a predictive accuracy of positive test of 70%, whereas thallium-201 scintigraphy achieved 88%, 100%, and 100%, respectively. Both angiographic and scintigraphic assessment showed a significant correlation with response grade as determined histologically (P < 0.05 and P < 0.0003, respectively). The alteration ratio of thallium-201 scintigraphy showed a strong, highly significant correlation with the percentage of tumor necrosis (P < 0.0001).

CONCLUSIONS

A change in the tumor uptake of thallium-201 scintigraphy after preoperative chemotherapy can predict the tumor necrosis in osteosarcoma precisely. Thallium scintigraphy is a noninvasive technique and seems to be more useful than angiography in assessing the response of osteosarcoma to preoperative chemotherapy.

Angiography for assessment of preoperative chemotherapy in musculoskeletal sarcomas

Eleven abnormal findings of digital subtraction angiography were analyzed in 25 patients with bone sarcoma and in 23 patients with soft tissue sarcoma. The relation between digital subtraction angiographic findings and the histologic effect of chemotherapy was evaluated. Digital subtraction angiography was performed with the patient under local anesthesia with the Seldinger technique, using an ADVANT X unit. Contrast medium was injected at a rate of 4 to 6 ml per second, with the usual single bolus dose of approximately 6 to 8 ml. Eleven abnormal findings included tumor stain, hypervascularity, arterial distortion, vascular stretch, arterial dilatation, arteriovenous shunt, arterial encasement, occlusion, blood pool, caliber with irregular wall, and dilatation of draining vein. Each finding after preoperative chemotherapy was compared with that before chemotherapy and divided into three grades; Grade 1, not effective; Grade 2, effective; and Grade 3, very effective. Angiographic Grades 2 and 3 were defined as responders. The histologic effect was examined and scored according to the modified classification proposed by Huvos. Histologic Grades 1 and 2 were classified as nonresponders and Grades 3 and 4 as good responders. In bone sarcomas, hypervascularity and tumor stain were seen in all patients. In soft tissue sarcomas, tumor stain was shown in all 23 patients and hypervascularity was seen in 21 patients. Tumor stain, hypervascularity, vascular stretch, and arterial encasement were correlated closely with histologic findings and showed an accuracy equal to or greater than 70%. When these four findings changed to angiographic Grade 3 after preoperative chemotherapy, 90% of patients had good histologic outcome.

Limb salvage and outcome of osteosarcoma. The University of Muenster experience

One hundred thirty-six patients with non-metastatic high grade osteosarcoma treated from 1978 to 1994 in one institution with a multidisciplinary approach that included intravenous neoadjuvant chemotherapy were studied to evaluate which factors influence the outcome of modern orthopaedic therapy. Anatomic location, tumor volume, surgical margins, complications, and functional outcome were analyzed. Seventy-nine patients had a limb salvage procedure, 21 had a rotationplasty, and 33 had an amputation. Limb salvage consisted of 32 endoprostheses, 39 allograft replacements, six autograft replacements, and two shortening procedures. Three patients died during preoperative chemotherapy treatment. At a mean followup of 43 months, 81 patients continue to be disease free, three are alive after local recurrence, 17 are alive after having metastatic lesions, five are alive with metastatic lesions present, and 30 patients died of their disease. Forty-seven patients had pulmonary metastatic lesions, 14 had osseous metastatic lesions, three had abdominal metastatic lesions, two had lymphatic metastatic lesions, and eight patients had skip metastatic lesions. Prognosis correlated with chemotherapy response, surgical margins, and tumor volume. The minor complication rate for limb salvage was 4% and the major complication rate was 52%. Amputations had a 6% minor complication rate and 34% major complication rate. Rotationplasties had 10% minor and 48% major complication rates. The Musculoskeletal Tumor Society functional evaluation after limb salvage showed that 23 (38%) patients had more than 75% of the maximum functional score, 34 (56%) were from 50% to 75%, and three (5%) less than 50%. Of the rotationplasties, six (67%) were functionally better than 75% and three (33%) were functionally better than from 50% to 75%. In the group of amputations, 13 (56%) were from 50% to 75%, and 10 (44%) less than 50%. The extent of preoperative necrosis, surgical margins, and tumor volume are the most important prognostic factors. The increase in limb salvage procedures and the better long term survival of patients results in a higher rate of immediate and delayed complications. Functional outcome after rotationplasty is superior to limb salvage reconstruction and amputation.

Evaluation of the effect of preoperative chemotherapy in bone sarcomas. 99mTc-HMDP scintigraphy in 34 cases

We quantitatively analyzed images of 99mTc-HMDP bone scintigraphy in 34 bone sarcomas before and after preoperative chemotherapy. The isotopic uptake was calculated as tumor-to-background ratio (TBR), and the changes in TBR before and after chemotherapy were calculated as the alteration ratio. The histological effect of preoperative chemotherapy was classified in 4 grades, according to Huvos. We defined good scintigraphic responders as cases having decreased uptake after chemotherapy, with an alteration ratio > or = 60%. There was a positive correlation (Rho = 0.76, p < 0.001) between the histological effect and the alteration ratio. Of the 17 good histological responders, 13 showed a good scintigraphic response. The average alteration ratio in 17 cases with good response (68%) was higher than that in 17 cases showing poor response (-9.9%) (p < 0.001). 3 patients with pathologic fractures and 1 with primarily normal uptake showed false negative findings. The sensitivity of this method was 100% and the specificity was 81%.

Hybrid artificial neural network segmentation and classification of dynamic contrast-enhanced MR imaging (DEMRI) of osteosarcoma

The evaluation of pediatric osteosarcoma has suffered from the lack of an accurate imaging measure of response. One major problem is that osteosarcoma do not shrink in response to chemotherapy; instead, viable tumor is replaced by necrotic tissue. Currently available techniques that use dynamic contrast-enhanced magnetic resonance imaging to quantitatively evaluate tumor response fail to assess the percentage of necrosis. At present, histopathologic evaluation of resected tissue is the only means of measuring the percentage of necrosis in treated osteosarcoma. The current study presents a non-invasive method to visualize necrotic and viable tumor and quantitatively assess the response of osteosarcoma. Our technique uses a hybrid neural network consisting of a Kohonen self-organizing map to segment dynamic contrast-enhanced magnetic resonance images and a multi-layer backpropagation neural network to classify the segmented images. Because the hybrid neural network is completely automated, our technique removes both inter- and intra-operator error. An analysis comparing the percentage of necrosis from our technique to the histopathologic analysis revealed a highly significant Spearman correlation coefficient of 0.617 with p < 0.001.

An integrated approach to the evaluation of osseous tumors

Modern treatment techniques for musculoskeletal neoplasms require significant imaging information to determine the nature and extent of tumors. The imaging investigation should be selected according to the information needed. Conventional radiographic techniques remain of fundamental importance in the analysis of bone tumors and tumor-like lesions, whereas advance imaging techniques such as CT and MR imaging can provide information regarding the extent of lesions.

Imaging assessment of the response of bone tumors to preoperative chemotherapy

Assessment of the response of bone tumors to preoperative chemotherapy is of clinical importance. The authors determined the value of 3 imaging techniques (digital subtraction angiography, thallium scintigraphy, and dynamic magnetic resonance imaging) in guiding patient management by assessing the response of 17 bone sarcomas to preoperative chemotherapy compared with histologic evaluation of the resected specimens. Digital subtraction angiography showed a sensitivity of 87.5%, specificity of 57.1%, and accuracy of 73.3%. Thallium scintigraphy (sensitivity, 85.7%; specificity, 85.7%; accuracy, 85.7%) was superior to angiography in predicting tumor responses. The results of dynamic magnetic resonance imaging were analyzed on the basis of the value of slopes, which represents the percent increase in signal intensity per minute. The differences in slope before and after chemotherapy and the postchemotherapy slope values correlated with the histologic responses. The assessment by dynamic magnetic resonance imaging showed a sensitivity of 100%, specificity of 85.7%, and accuracy of 90.9%. Thallium scintigraphy and dynamic magnetic resonance imaging were considered noninvasive, reliable techniques that had about equal ability to assess the response of bone sarcomas to preoperative chemotherapy. Dynamic magnetic resonance imaging offers major advantages in the spatial resolution and can be more readily quantitated when compared with thallium scintigraphy.

Monitoring neovascularity as an indicator to response to chemotherapy in osteogenic and Ewing sarcoma using magnetic resonance angiography

Histologic studies on resected specimen have shown that tumor neovascularity is related to prognosis and response to therapy in a variety of human neoplasms. In nine patients with osteogenic or Ewing sarcoma, we evaluated the use of magnetic resonance angiography (MRA) to assess neovascularity non-invasively in vivo and to monitor response to chemotherapy. Seven patients with osteosarcoma and two patients with Ewing sarcoma were studied before and after chemotherapy by MRA (2-D time-of-flight gradient-echo sequence, TR = 50 msec, TE = 9.5 msec, theta = 50 degrees, acquisition time 13 min). MR angiograms were assessed for chemotherapy-induced changes in neovascularity. MRA showed both feeder vessels and neovascularity. Six patients responded to chemotherapy ( > or = 90% histologic tumor necrosis). MRA demonstrated marked reduction in neovascularity in all responders. Three patients did not respond to chemotherapy ( < 90% histologic tumor necrosis). MRA demonstrated persistent or increased neovascularity in the non-responders. MRA provides a unique opportunity to study tumoral neovascularity noninvasively in vivo and helps to assess response to chemotherapy in patients with osteogenic or Ewing sarcoma. These general principles may be applicable to other human tumors.

Dynamic contrast-enhanced MR imaging of musculoskeletal tumors: basic principles and clinical applications

The purpose of this article is to review the basic principles and clinical applications of dynamic contrast-enhanced MRI in the musculoskeletal system. This method of physiologic imaging provides clinically useful information by depicting tissue vascularization and perfusion, capillary permeability, and composition of the interstitial space. Different imaging, evaluation, and postprocessing techniques are described. The most important applications in the musculoskeletal system are identification of areas of viable tumor for biopsy, tissue characterization, and monitoring of preoperative chemotherapy. Practical guidelines for performing a dynamic contrast-enhanced MR examination are proposed.

Dynamic contrast-enhanced MR imaging evaluation of osteosarcoma response to neoadjuvant chemotherapy

Assessment of osteosarcoma response to neoadjuvant chemotherapy has prognostic implications, but conventional imaging techniques have been unable to provide an accurate quantitative measure of tumor response. We developed an analysis of dynamic contrast-enhanced MR imaging (DEMRI) to render an image of dynamic vector magnitudes (DVM) and to summarize the result in a quantitative parameter, mean DVM for the lesion (mu DVM). We compared the mu DVM from the examination before surgery with histologic results from an en bloc resection of the tumor in 19 cases. The final mu DVM value provided an accurate (89.5%) measure of tumor necrosis in osteosarcoma. Further, we analyzed the findings in 17 patients with osteosarcoma who completed three DEMRI examinations during the course of therapy. Tumors with higher mu DVM values at presentation had greater decreases in the parameter over the course of therapy. These results are consistent with the distribution of DVM values in these lesions serving as an indicator of tumor perfusion and a possible surrogate variable for drug delivery.

First-pass images of musculoskeletal lesions: a new and useful diagnostic application of dynamic contrast-enhanced MRI

The purpose of this study was to evaluate the diagnostic value of parametric images which display the first-pass of Gd-DTPA after intravenous bolus injection. Single slice dynamic contrast-enhanced MRI (Turbo-FLASH) with a temporal resolution of 2.41 s was performed in 40 benign and malignant musculoskeletal lesions. Parametric 'first-pass' images were obtained by using a new postprocessing technique, derived from a home written computer program, which calculated the steepest slope of the time-intensity curve pixel by pixel. First-pass images provided qualitative and quantitative information, which was useful for diagnosis and therapy. Demonstration of the areas with the highest vascularization was very helpful in planning the best biopsy site in 6 patients and to delineate tumor from peritumoral muscle edema in 4 patients. In 10 patients the first-pass images provided additional information, which was not visible on the conventional spin-echo images. The most promising application was the ability to evaluate the response to preoperative chemotherapy in a patient with Ewing's sarcoma. Although a highly statistically significant difference (p < 0.001) was found between the first-pass slope values of benign and malignant lesions, the sensitivity (77%) and specificity (71%) of this method were too low to permit a definite differentiation of highly vascular benign from malignant lesions. Pathologic examination of 17 lesions, performed in the plane of the first-pass image, showed a good correlation between the first-pass slope values and the vascularization of the tissues.(ABSTRACT TRUNCATED AT 250 WORDS)

Tissue characterization and assessment of preoperative chemotherapeutic response in musculoskeletal tumors by in vivo 31P magnetic resonance spectroscopy

This study investigates the potential of in vivo 31P magnetic resonance spectroscopy (MRS) to characterize musculoskeletal tumors and to determine preoperative levels of histological necrosis, which is an important clinical indicator of patient response. Pretherapy MRS was performed on 28 patients with large musculoskeletal tumors: 13 with osteosarcoma, 3 with chondrosarcoma, 5 with malignant fibrous histiocytoma, 1 with desmoid tumor, 1 with Ewing's, 2 with hemangioendothelioma, 1 with myxoid liposarcoma, 1 with synovial cell sarcoma, and 1 with rhabdomyosarcoma. Fifteen patients had follow-up MRS examinations after commencement of chemotherapy (mean of five/patient), eight of whom have now had surgery. Elevated levels of PMEs (P < 0.01), P(i) (P < 0.01), and PDEs (P < 0.02) as well as elevated tumor pH (P < 0.05) were observed in all patients. The synovial cell sarcoma was characterized by high levels of PMEs (> 20%) and low pH (pH 6.76). This contrasted with the spectra obtained from the malignant fibrous histiocytomas which had high levels of PDEs (17 +/- 5%). Reductions in PDE levels postchemotherapy were associated with a high degree of necrosis (> 90%) at surgery, while an increase in PDE levels was associated with a low level of histological necrosis. Likewise, reductions in the ratios PDE/NTP and PDE/PCr and an increase in P(i)/PDE were also associated with a high level of necrosis.

Osteosarcoma. Clinical features and evolving surgical and chemotherapeutic strategies

Osteosarcoma is the most common neoplasm of bone in children and adolescents. The first effective therapy became available in the early 1970s, and although controversy existed for several years regarding the relative value of aggressive multiagent chemotherapy, presently about 60% of patients with resectable primary tumors and no metastases at diagnosis will be cured. New imaging methods, including computerized tomography, magnetic resonance imaging, and radionuclide techniques, that are sensitive to changes in local tumor perfusion have improved the ability to define the extent of tumor and the response to chemotherapy, and to plan surgery. Although amputation historically has been the primary method for local tumor control, newer surgical techniques and endoprosthetic devices, coupled with effective preoperative chemotherapy, have offered less radical surgery for 50% to 80% of patients with osteosarcoma. New therapeutic agents, including ifosfamide and the immunosuppressive drug, muramyl tripeptide phosphatidylethanolamine, hold promise for improvement in the cure rate of osteosarcoma.

Imaging bone tumors in the 1990s

Progress in bone tumor management has occurred as a result of cooperation among surgeons, oncologists, pathologists, and radiologists. During the 1990s radiologists will contribute to care of patients with bone tumors in major ways. Tumor detection and preliminary diagnosis will be accomplished by radiography. Tumor local extent will be assessed by magnetic resonance imaging (MRI) and to a lesser degree by computed tomography (CT). Distant spread of malignancy will be documented by radionuclide scintigraphy (skeleton) and by CT (lungs). The combined estimate of local extent and distant spread will assure adequate staging before definitive management decisions. Preoperative closed percutaneous biopsy for histologic diagnosis will be accomplished on an outpatient basis under fluoroscopic or CT guidance. Arteriography will be employed for delivery of local chemotherapy. Some combination of arteriography, MRI, and MR spectroscopy will be used to evaluate tumor response. After limb-salvage surgery, MRI will sequentially assess the tumor bed; bone scintigraphy and CT will detect skeletal and pulmonary metastases. The radiologist's role will undergo continuous redefinition.

Radiotherapy prior to cortical allograft limb sparing in dogs with osteosarcoma: a dose response assay

Twenty-one dogs with spontaneously occurring appendicular osteosarcoma were given preoperative radiation therapy prior to a limb sparing procedure using a cortical allograft. Radiation doses were randomly assigned, ranged from 36-52 Gy in 4 Gy intervals, and were given in 10 equally-sized fractions on a M, W, F schedule. Seventeen of the 21 dogs underwent the limb sparing procedure approximately 3 weeks after completion of radiation therapy. Local tumor recurrence was documented in 4 of 17 dogs at mean and median times of 5.5 and 5.8 months, respectively, after initiation of radiation therapy. Three of 4 recurrences were in anatomic regions with sparse adjacent soft tissue which precluded wide excision. Complications were significant. Fixation device failure occurred in 9 of 17 dogs and was associated with host bone necrosis, muscle thinning and fibrosis of vessels and nerves in irradiated normal tissue. Incidence of host bone necrosis was directly related to radiation dose (Kendall's statistic, p = 0.005). Metastasis occurred in all 21 dogs. Mean and median times to metastasis in these dogs were 5.1 and 4.0 months, respectively, after initiation of radiation therapy. Local tumor control rates and survival times were higher in dogs developing allograft infection suggesting that infection acted as an immunostimulant. All local failures occurred in dogs that did not develop allograft infection and median survival times for uninfected versus infected dogs were 5 and 11 months, respectively (logrank test, p = 0.029). Increased tumor radiopacity following radiation therapy was significantly related to survival. Median survival in dogs whose tumors were characterized by decreased, unchanged or increased opacity after radiation therapy were 3.5 and 14 months, respectively (logrank test, p = 0.014). Based on the results of our study, radiation therapy can not be recommended as part of limb sparing treatments for patients with osteosarcoma at doses and dose per fraction values similar to those used herein.

Scintigraphic evaluation of tumor regression during preoperative chemotherapy of osteosarcoma. Correlation of 99mTc-methylene diphosphonate parametric imaging with surgical histopathology

The effect of preoperative chemotherapy (PCT) on the uptake of 99mTc-labeled diphosphonates into tumor bone was quantitatively assessed from serial scan studies of 30 osteosarcomas and correlated with the histomorphological changes determined from the surgical specimens. The parametric images of the tumor blood pool and labeled methylene diphosphonate (99mTc-MDP) plasma clearance by the tumor bone enabled a sensitive distinction to be made preoperatively between a good (greater than 90% tumor cell destruction) and a poor (less than 90% tumor cell destruction) tumor response. Overall accuracy in presurgical prediction of tumor regression was found to be 88% and 96% for the blood pool and 99mTc-MDP clearance measurements, respectively (P less than or equal to 0.0004). In addition, it proved possible to localize resisting areas of viable tumor up to 1.0 cm in diameter. Even at the half-way stage of PCT, a poor response could be reliably predicted (overall accuracy 91% and 100%, respectively; P less than or equal to 0.011). Therefore, 99mTc-MDP parametric imaging is a highly sensitive and specific modality for an objective and accurate assessment of tumor regression during PCT of osteosarcoma.