Osteosarcoma of the Extremity Metastatic at Presentation: Results Achieved in 26 Patients Treated with Combined Therapy (Primary Chemotherapy Followed by Simultaneous Resection of the Primary and Metastatic Lesions)

Japanese orthopaedic association (JOA) clinical practice guidelines on the management of malignant bone tumors - Secondary publication

BACKGROUND

In Japan, there are currently no general guidelines for the treatment of primary malignant bone tumors. Therefore, the Japanese Orthopaedic Association established a committee to develop guidelines for the appropriate diagnosis and treatment of primary malignant bone tumors for medical professionals in clinical practice.

METHODS

The guidelines were developed in accordance with "Minds Clinical Practice Guideline Development Handbook 2014″ and "Minds Clinical Practice Guideline Development Manual 2017". The Japanese Orthopaedic Association's Bone and Soft Tissue Tumor Committee established guideline development and systematic review committees, drawing members from orthopedic specialists leading the diagnosis and treatment of bone and soft tissue tumors. Pediatricians, radiologists, and diagnostic pathologists were added to both committees because of the importance of multidisciplinary treatment. Based on the diagnosis and treatment algorithm for primary malignant bone tumors, important decision-making points were selected, and clinical questions (CQ) were determined. The strength of recommendation was rated on two levels and the strength of evidence was rated on four levels. The recommendations published were selected based on agreement by 70% or more of the voters.

RESULTS

The guideline development committee examined the important clinical issues in the clinical algorithm and selected 22 CQs. The systematic review committee reviewed the evidence concerning each CQ and a clinical value judgment was added by experts. Eventually, 25 questions were published and the text of each recommendation was determined.

CONCLUSION

Since primary malignant bone tumors are rare, there is a dearth of strong evidence based on randomized controlled trials, and recommendations cannot be applied to all the patients. In clinical practice, appropriate treatment of patients with primary malignant bone tumors should be based on the histopathological diagnosis and degree of progression of each case, using these guidelines as a reference.

Osteosarcoma and Its Advancement

Cancer with its high mortality rate is really hard to treat even in this era. Extensive research work is still required to overcome the threat caused by the disease. Currently, the treatment modality is based on the combination therapy, and diagnostics is dependent upon biopsy results. Once the stage of cancer is clear, the treatment is prescribed. To bring a successful treatment approach of patients with osteosarcoma, it requires multidisciplinary team approach including pediatric, medical and surgical oncologist, surgeons, pathologists, pain management, orthopedic oncologist, endocrinologist, and radiologists. Therefore, cancer treatment is to be performed in specialized hospitals able to provide access to all approaches with multidisciplinary team care.

Radiomics Analysis of Multiparametric MRI for Prediction of Synchronous Lung Metastases in Osteosarcoma

Purpose

To establish and verify a predictive model involving multiparameter MRI and clinical manifestations for predicting synchronous lung metastases (SLM) in osteosarcoma.

Materials and Methods

Seventy-eight consecutive patients with osteosarcoma (training dataset, n = 54; validation dataset, n = 24) were enrolled in our study. MRI features were extracted from the T1‐weighted image (T1WI), T2‐weighted image (T2WI), and contrast-enhanced T1-weighted image (CE-T1WI) of each patient. Least absolute shrinkage and selection operator (LASSO) regression and multifactor logistic regression were performed to select key features and build radiomics models in conjunction with logistic regression (LR) and support vector machine (SVM) classifiers. Eight individual models based on T1WI, T2WI, CE-T1WI, T1WI+T2WI, T1WI+CE-T1WI, T2WI+CE-T1WI, T1WI+T2WI+CE-T1WI, and clinical features, as well as two combined models, were built. The area under the receiver operating characteristic curve (AUC), sensitivity and specificity were employed to assess the different models.

Results

Tumor size was the most significant univariate clinical indicator (1). The AUC values of the LR predictive model based on T1WI, T2WI, CE-T1WI, T1WI+T2WI, T1WI+CE-T1WI, T2WI+CE-T1WI, and T1WI+T2WI+CE-T1WI were 0.686, 0.85, 0.87, 0.879, 0.736, 0.85, and 0.914, respectively (2). The AUC values of the SVM predictive model based on T1WI, T2WI, CE-T1WI, T1WI+T2WI, T1WI +CE-T1WI, T2WI +CE-T1WI, and T1WI+T2WI+CE-T1WI were 0.629, 0.829, 0.771, 0.879, 0.643, 0.829, and 0.929, respectively (3). The AUC values of the clinical, combined 1 (clinical and LR-radiomics) and combined 2 (clinical and SVM-radiomics) predictive models were 0.779, 0.957, and 0.943, respectively.

Conclusion

The combined model exhibited good performance in predicting osteosarcoma SLM and may be helpful in clinical decision-making.

Current Treatment Considerations for Osteosarcoma Metastatic at Presentation

Approximately one-fourth of osteosarcoma patients have metastases at presentation. The best treatment options for these patients include chemotherapy, surgery, and radiotherapy; however, the optimal scheme has not yet been defined. Standard chemotherapy for osteosarcoma metastatic at presentation is based on high-dose methotrexate, doxorubicin, and cisplatin (the MAP regimen), with the possible addition of ifosfamide. Surgical treatment continues to be fundamental; complete surgical resection of all sites of disease (primary and metastatic) remains essential for survival. In patients whose tumors do not respond to neoadjuvant chemotherapy, early surgical resection of the primary tumor with limb-salvage surgery or amputation and multiple metastasectomies, if feasible, after the completion of adjuvant chemotherapy is a reasonable option, as the reduction of the tumor volume could probably increase the effect of chemotherapy. Advanced radiotherapy techniques, such as carbon ion radiotherapy and stereotactic radiosurgery, and molecular targeted chemo-therapy with drugs such as pazopanib or apatinib have improved the dismal prognosis, especially for patients who are medically inoperable or who refuse surgery. Given that the presence of metastatic disease at diagnosis of a patient with osteosarcoma is a poor prognostic factor, a multidisciplinary approach by surgeons, medical oncologists, and radiotherapists is important. [Orthopedics. 2020;43(5):e345-e358.].

The prognosis for patients with osteosarcoma who have received prior manipulative therapy

We evaluated the long-term outcome of patients with an osteosarcoma who had undergone prior manipulative therapy, a popular treatment in Asia, and investigated its effects on several prognostic factors. Of the 134 patients in this study, 70 (52%) patients had manipulative therapy and 64 (48%) did not. The age, location, and size of tumour were not significantly different between the groups. The five-year overall survival rate was 58% and 92% in the groups with and without manipulative therapy (p = 0.004). Both the primary and overall rates of lung metastasis were significantly higher in the manipulative group (primary: 32% vs 3%, p = 0.003; overall lung metastasis rate: 51.4% vs 18.8%, p < 0.001). Patients who had manipulative therapy had higher local recurrence rates in comparison to patients who did not (29% vs 6%, p = 0.011). The prognosis for patients with osteosarcoma who had manipulative therapy was significantly poorer than those who had not. Manipulative therapy was an independent factor for survival. This form of therapy may serve as a mechanism to accelerate the spread of tumour cells, and therefore must be avoided in order to improve the outcome for patients with an osteosarcoma.

The metastasectomy and timing of pulmonary metastases on the outcome of osteosarcoma patients

Background:

The author intended to clarify the therapeutic effect and prognostic factors of metastasectomy and timing of pulmonary metastases in osteosarcoma patents.

Methods:

Data was obtained retrospectively on all consecutive osteosarcoma patients from 1985 to 2005 in author’s institute. Fifty-two patients with pulmonary nodules were identified, including 24 patients undergoing pulmonary metastasectomy treatment. These patients were categorized into four groups: group 1, patients with lung metastases at the initial presentation; group 2, lung metastases identified during the period of pre-operative chemotherapy; group 3, lung metastases identified during period of the post-operative che motherapy; group 4, lung metastases identified after therapy for the primary osteosarcoma completed.

Results:

In our study, the 2-, 3-, and 5-year overall survival rates for 52 patients were 49%, 39% and 20%. The 2-year overall survival rates were 18% for group 1, 32% for group 3, and 70% for group 4 (p < 0.001). The 5-year overall survival rate was 34% for group 4. Patients who underwent metastesectomy showed a better survival outcome as compared with the patients not undergoing metastasectomy (p = 0.003). The 2-year and 5-year overall survival rates of only one lung metastatic nodule were 62% and 50%, and for initially multiple lung metastatic nodules, 45% and 5%, respectively. In addition, the patients presented with lung metastases had a worse prognosis as compared with those without initial lung metastases (p = 0.0001).

Conclusions:

The patients having single metastatic nodule showed a better prognosis than those with multiple lung nodules. Furthermore, those patients who underwent metastasectomy survived longer than those not undergoing metastasectomy. Patients who had late metastases after complete chemotherapy had a better prognosis; whereas those who had metastases identified at the initial presentation predicted a poor prognosis.

High-dose ifosfamide in relapsed pediatric osteosarcoma: therapeutic effects and renal toxicity

BACKGROUND

Sixteen pediatric osteosarcoma patients, previously treated with conventional chemotherapy (including ifosfamide (IFX), 9 g/m(2)) were retreated with high-dose ifosfamide (HD-IFX, 14 g/m(2) per course), following relapse or development of a new bone tumor. The objective was to obtain responses and an improved event-free survival (EFS).

PROCEDURE

HD-IFX was administered as described by Patel SR: J Clin Oncol 1997;15:2378. Efficacy of treatment was assessed initially after two to four courses. The interval between the courses was 3 to 4 weeks. Provided a response was obtained after two to four courses, treatment was continued for an additional eight courses unless progressive disease or an untoward event, for example, renal failure occurred. Tumor sites were: lung, (10) bone (9), and bone and soft-tissue (1).

RESULTS

Response after two to four courses was 62.5%: CR 6 and PR 4. A total of 84 courses were administered to the 16 patients: (range 2-10, median 5.5 per patient). Median interval between courses was 28.5 days (range 15-90). Five patients were disease free at 15+ to 63+ months after induction and maintenance therapy. Fever and neutropenia occurred in 12 courses. Nephrotoxicity was a major toxic event and was characterized by creatinine levels at or above three times the upper limit of normal. It was unpredictable and occurred in four patients: two were reversible. The other two patients developed full-blown renal failure; one was treated with renal dialysis, but both eventually succumbed to osteosarcoma. Our past experience also indicated that two patients treated with IFX (9 g/m(2)/course) developed renal failure: one recovered and the other required a renal transplant.

CONCLUSIONS

HD-IFX is effective in patients who have failed conventional chemotherapy including IFX (9 g/m(2)). Improved disease-free survival was achieved in 30% of patients. However, renal failure constitutes an important life-threatening complication and its development is unpredictable.

Surgical management and outcome of osteosarcoma patients with unilateral pulmonary metastases

PURPOSE

The surgical management of osteosarcoma patients with unilateral pulmonary nodules is controversial. The authors reviewed their institutional experience to evaluate the incidence of occult contralateral metastases.

METHODS

Data were obtained retrospectively on all consecutive osteosarcoma patients from 1980 to 2002. Eighty-four patients with pulmonary nodules were identified. Forty-one had bilateral disease, and 43 had unilateral involvement by computed tomography (CT) scan.

RESULTS

All 43 patients with unilateral nodules underwent ipsilateral thoracotomies. Fifteen patients had negative exploration findings, and only 1 had pulmonary relapse. Of the 28 patients with metastases confirmed at initial thoracotomies, 14 had extensive pleural or extrapulmonary disease at initial thoracotomy followed by disease progression. The other 14 are separated into early versus late metastases, using 2 years from diagnosis as the cutoff point. Seven of the 9 (78%) patients with early metastases had or subsequently had contralateral disease; 6 were identified at staged contralateral thoracotomy and 1 had relapsed in the unexplored lung a year later. Only 1 of the 5 patients with late unilateral metastases had relapse in the contralateral side.

CONCLUSIONS

Our data indicate that there is a high rate of contralateral involvement in osteosarcoma patients with unilateral nodules diagnosed by CT scan. Staged bilateral thoracotomies should be considered in osteosarcoma patients presenting with unilateral pulmonary disease on imaging studies within 2 years of diagnosis.

A pilot study of short-course intensive multiagent chemotherapy in metastatic and axial skeletal osteosarcoma

BACKGROUND

This pilot study was undertaken to assess the feasibility, toxicity and response to short-course multiagent chemotherapy followed by high-dose chemotherapy (HDC) in patients with poor prognosis osteosarcoma.

PATIENTS AND METHODS

A total of 30 patients entered the study. Chemotherapy consisted of four blocks of multiagent chemotherapy administered sequentially over a short period in a dose-intensive manner. This therapy was followed by HDC which consisted of carboplatin at an AUC8 x 3 days, etoposide 400 mg/m(2) x 3 days and cyclophosphamide 60 mg/kg x 2 days.

RESULTS

A total of 227 cycles of chemotherapy were administered. The main toxicity (for blocks 1-4) was haematological. There were two treatment-related deaths: one post HDC due to sepsis and one during surgery. High-dose chemotherapy was administered to 11 patients (10 with extremity tumours and only one with a pelvic tumour). Twenty-seven patients underwent surgery to the primary. Histological response was assessed in 23 patients. Seven patients (30%) had >90% necrosis. Eight patients underwent pulmonary metastatectomy. The median survival time for the whole group was 16 months. The 2- and 3-year survival rates were 50% and 21% for those with extremity tumours and 19% and 13% for those with axial skeletal tumours.

CONCLUSIONS

Dose-intensive multiagent chemotherapy though feasible in the group of patients with extremity tumours did not significantly improve the treatment outcome compared with conventional relapse therapy. Inferior survival rates in the axial skeletal group are attributed to less intensive treatment and poor local tumour control.

Results of treatment for metastatic osteosarcoma with neoadjuvant chemotherapy and surgery

The purpose of the current study was to define the survival outcome variables for the 85 patients with Stage IIB osteosarcoma treated with neoadjuvant chemotherapy at the authors' institution from 1982 to 1997. A minimum 4-year followup or death was a requisite for inclusion. Forty-three patients were relapse-free survivors and 14 had no evidence of disease at followup for an overall survival of 67%. Twenty-nine patients had thoracotomy and nine have no evidence of disease with a minimum 4-year followup from last thoracotomy. The mean time to metastasis after diagnosis for patients presenting with Stage IIB disease was 12.8 months. There was no difference in the survival for any of the three chemotherapy protocols, used during the 15 years included in this analysis. There was a significant relation between length of time to relapse and survival. For each additional year without relapse, there is an 18% increase in chance of survival. In patients who were treated with thoracotomy, the number of metastatic nodules was a significant predictor of survival; specifically, each nodule increased the risk of death by 43%. A favorable outcome in this cohort of patients is related to the length of time between initiation of therapy and diagnosis of metastasis, and the number of metastatic foci.

Phase II/III trial of etoposide and high-dose ifosfamide in newly diagnosed metastatic osteosarcoma: a pediatric oncology group trial

PURPOSE

The objectives of this trial were to estimate the response rate, progression-free survival, and overall survival of patients who received therapy with etoposide and high-dose ifosfamide, and to define the toxicity of this combination when provided with standard chemotherapy in patients with newly diagnosed metastatic osteosarcoma.

PATIENTS AND METHODS

Eligible patients received infusions of 100 mg/m(2) per day of etoposide and 3.5 g/m(2) per day of ifosfamide for 5 days. Therapy with granulocyte colony-stimulating factor was begun on day 6. This was repeated 3 weeks after therapy was begun. Response was determined at week 6 by both standard World Health Organization response criteria and by pathologic determination of tumor necrosis of the primary tumor.

RESULTS

Forty-three patients were registered; 39 were assessable for response and 41 for toxicity and survival. Twenty-eight (68%) of 41 had metastatic sites only in the lung; 12 (29%) had metastatic sites in other bones with or without lung involvement. Four patients (10%) experienced complete response, and 19 patients (49%) experienced partial response, for an overall response rate of 59% +/- 8%. The projected 2-year progression-free survival (PFS) for the 28 patients with metastases to lungs was 39% +/- 11%. The projected 2-year PFS for the 12 patients with metastases to other bones (with or without pulmonary metastases) was 58% +/- 17%. Two patients died as a result of therapy toxicity. Eighty-three percent of patients had grade 4 neutropenia, and 29% had grade 4 thrombocytopenia. Ten patients (24%) had sepsis. Fanconi's syndrome was observed in five patients.

CONCLUSION

The combination of etoposide and high-dose ifosfamide is effective induction chemotherapy for patients with metastatic osteosarcoma, despite significant associated myelosuppression sometimes complicated by infection and renal toxicity.

Presurgical window of carboplatin and surgery and multidrug chemotherapy for the treatment of newly diagnosed metastatic or unresectable osteosarcoma: Pediatric Oncology Group Trial

PURPOSE

Relapse remains a significant problem in patients with metastatic osteosarcoma. The response to carboplatin of patients with newly diagnosed metastatic or unresectable osteosarcoma was assessed in an upfront phase II window, which was followed-up by surgery and intensive multiagent chemotherapy.

PATIENTS AND METHODS

Thirty-seven patients, ages 3 to 23 years with histologically confirmed diagnoses of osteosarcoma, were treated between January 1992 and November 1994 with carboplatin 1,000 mg/m2 per dose administered as a 48-hour continuous infusion. Two courses were administered in 3-week intervals, depending on marrow recovery. After radiographic reevaluation, patients underwent surgical removal of tumor (if feasible) and then 40 weeks of chemotherapy with high-dose methotrexate, ifosfamide, doxorubicin, and cisplatin.

RESULTS

One of the 37 evaluable patients demonstrated a partial response to carboplatin; there were no complete responses. Patients were additionally analyzed by the response of pulmonary metastases to therapy and the extent of tumor necrosis of the primary lesion. By these criteria, 8 of 37 (22%) of patients showed a response at one or more sites, whereas 20 of 37 (54%) had unequivocal disease progression. Severe myelosuppression was the major toxicity. The projected 3-year event-free and overall survival rates were 23.9% and 31.9%, respectively. Only 1 of 17 patients with unresectable disease or distant bone metastases remains alive, in contrast to 6 of 17 patients with the lung as their only metastatic site and two of three patients with resected regional bone metastases.

CONCLUSIONS

Continuous-infusion carboplatin demonstrated limited activity as an upfront agent in patients with metastatic osteosarcoma at diagnosis, even at doses that result in severe and prolonged myelosuppression. Patients with isolated pulmonary metastases or resectable bone metastases have a longer median survival time and greater chance of long-term survival than do patients with unresectable bone disease, for whom the prognosis remains dismal.

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.

Limb-saving surgery, survival, and prognostic factors for osteosarcoma: the Hungarian experience

BACKGROUND AND OBJECTIVES

There are many factors thought to have an influence on the prognosis of osteosarcoma that have been reported in the literature. Their significance, however, still remains controversial in most cases. Experience with osteogenic sarcoma (OS) was reviewed in order to evaluate surgical results and survival and to determine the prognostic factors.

METHODS

Ninety-six patients with high-grade osteosarcoma of the extremities were treated between 1986 and 1997 in the authors' institution. They were divided into 3 groups: In group I, all 75 patients with nonmetastatic OS received intensive chemotherapy (high-dose methotrexate, doxorubicin, ifosfamide, and cisplatin) and underwent surgery. In group II, 9 patients already had metastases at the time of referral. In group III, 12 patients received chemotherapy in delayed or suboptimal form. Results and Conclusions In group I, there were local recurrences in 3 patients (7%) and metastases in 8 patients (20%) with limb-saving, whereas these numbers were 1 (3%) and 14 (38%) in those who had amputation. The 5-year disease-free survival (DFS) was 72% and 69% in the limb-saving and amputation groups, respectively. In groups II and III, 5-year DFS was extremely poor, 10% and 20% only, underlining the importance of stage and intensity of chemotherapy, respectively. With univariate analysis, sex, duration of symptoms, and radiographic appearance of OS had no prognostic value, whereas tumor volume <60 cm(3), wide or radical surgical margin, distal location of OS, cartilagineous ground substance <20%, and response to chemotherapy were positive prognostic factors. The last 4 variables maintained their significance in the multivariate Cox model as well. Age >30 years showed indirect negative influence on the final outcome through enhanced intolerability to the drugs and less cooperability of the patients. The results on survival with limb-saving surgery were well comparable with those of amputation.

Ifosfamide/etoposide alternating with high-dose methotrexate: evaluation of a chemotherapy regimen for poor-risk osteosarcoma

Fifteen patients with relapsed osteosarcoma were treated with an intensive combination chemotherapy schedule. Ifosfamide 2.5 g m(-2) daily and etoposide 150 mg m(-2) daily coincidentally for 3 days and high-dose methotrexate 8 g m(-2) (with folinic acid rescue) on days 10-14 in a planned 21 -day cycle. Feasibility, toxicity and response to this alternative combination for the treatment of relapsed osteosarcoma was assessed. There were 98 evaluable cycles for toxicity and tolerability. The majority of cycles were well tolerated. Haematological toxicity of grade 3/4 (common toxicity criteria) was seen in all courses. Renal tubular loss of electrolytes, particularly magnesium, occurred in 71% of cycles. Thirteen per cent of cycles were repeated within 21 days and 61% within 28 days. In the thirteen patients evaluable for response, a partial response rate of 31% was seen after two cycles. However, patients with stable disease continued on therapy, and an overall consequent response rate of 62% was observed. Four patients were alive with no evidence of disease at 8-74 months. Three are alive with disease (at 8-19 months). There were six deaths, all disease related. This regimen exhibits an encouraging response rate in a group of children with poor prognosis disease, with a tolerable toxicity profile.

Evaluation of follow-up investigations in osteosarcoma patients: suggestions for an effective follow-up program

BACKGROUND AND PROCEDURE

Follow-up programs for cancer patients aim at improving the overall prognosis by early detection of relapse. In this study, follow-up data from 72 osteosarcoma patients were received in order to determine the value of clinical examination (CE), lung CT-scan (CTL), chest X-ray (CXR), local X-ray (LXR), and bone scintigraphy (BS) in the detection of tumor recurrence.

PROCEDURE

Twenty-eight of 72 osteosarcoma patients presented with a total of 61 relapse sites. A continuous remission after relapse treatment could be achieved in 2/16 patients with first lung metastases, in 2/6 patients with local relapse, and in 3/19 patients with more than one lung metastasis. More than 90% of all relapses occurred within 3 years off primary therapy, respectively, within 3 years after detection of relapse. Local relapse and lung metastases were primarily diagnosed by CXR, CTL and CE. BS was the most important investigation to detect distant metastases. No relapse was found by routine X-ray of the primary tumor site.

CONCLUSIONS

To improve efficacy of follow-up programs and to reduce radiation load of nonrelapsed patients, the prognosis of patients with lung metastases or local recurrences and the time of high risk for a relapse should be taken into consideration. Since the number of patients who benefit from relapse therapy is still low, it remains to be shown whether an increased frequency of lung CT-scans or MRIs of the primary tumor site will improve early detection of relapse; and if so, whether that will enhance the chance for successful relapse treatment. CXR, CTL and CE should be performed routinely for at least 3 years after completion of therapy or relapse diagnosis. In contrast, BS and LXR appear not to be useful as routine investigations.

P-glycoprotein expression: critical determinant in the response to osteosarcoma chemotherapy

BACKGROUND

Fewer than 20% of patients with bone cancer who are treated with surgery alone are cured. Even with the best current treatment, surgery combined with chemotherapy, only 60%-80% of patients with nonmetastatic bone cancer and 10% of patients with metastatic bone cancer are cured. Thus far, the reason for treatment failure in the nonresponding subset has not been identified. It has been hypothesized that P-glycoprotein, which confers multidrug resistance, might be the cause. We sought to determine whether the expression of P-glycoprotein is associated with poor treatment outcome in osteosarcoma.

METHODS

In a retrospective study, we correlated P-glycoprotein expression with the outcome of conventional chemotherapy in 62 consecutive, clinically staged patients diagnosed as having osteosarcoma between 1980 and 1989.

RESULTS

P-glycoprotein was overexpressed in 27 patients but not in another 34 patients, and expression was ambiguous in the sample from one patient. At a median follow-up of 8.9 years, the 34 patients whose tumors did not express P-glycoprotein had significantly better relapse-free rates than the 27 subjects whose tumors expressed the protein (87% versus 0%; P<.00001) and had improved survival rates (94% versus 35%; P<.00001). Among the 46 patients who received chemotherapy before surgery, the 23 whose tumors were negative for P-glycoprotein showed significantly better long-term outcomes (P<.00002), although differences in tumor necrosis in response to therapy were only of borderline significance (P = .057).

CONCLUSIONS

P-glycoprotein expression does correlate with treatment failure in patients with osteosarcoma. This correlation raises the possibility that inhibiting the action of P-glycoprotein as part of therapy for this disease would improve outcome.

Prognostic factors in bone sarcomas

Based on a literature review and the SSG experience, the most important prognostic factors in high-grade osteosarcoma appear to be the presence of detectable metastases at diagnosis, tumour volume, old age, sex, histologic response, and possibly tumoral P-glycoprotein expression. However, for an adolescent patient with non-metastatic extremity disease, there is no consensus regarding prognostic factors at initial presentation, and currently there is thus no established method for dividing them into high- and low risk groups for the purpose of treatment differentiation. It should also be remembered that available prognostic factors have been identified only in a retrospective manner, following aggressive treatment of all patients. Thus patients in "favourable" prognostic groups may simply be patients who have had a good effect from aggressive treatment, and how they would have done with reduced treatment remains to be shown. Obviously the best method for prognostication would be the direct demonstration of micrometastatic disease in the lungs or in peripheral blood. In the relatively near future, this may become possible with immunoscintigrapy or immunohistochemistry utilizing monoclonal antibodies [29-31]. In Ewing's sarcoma, the most powerful factors indicating poor prognosis are metastases at diagnosis, poor histologic response, large tumour size and possibly pelvic localisation. There appears to be a somewhat better international consensus regarding prognostic factors in Ewing's sarcoma than in osteosarcoma. Although several studies have implemented intensified treatment for poor prognostic groups [8, 32], the role (if any) of high-dose treatment with stem cell rescue remains to be proven. The same factors are prognostic both for the development of metastases and local recurrence, but in addition, surgical treatment as opposed to radiotherapy appears to reduce local failure rate [12, 17, 33, 34]. As in osteosarcoma, the near future offers promise regarding the detection and quantification of micrometastatses and minimal residual disease, by means of PCR techniques recognizing specific genetic changes in the Ewing family of tumors [35].

Treatment of osteosarcoma with ifosfamide: comparison of response in pediatric patients with recurrent disease versus patients previously untreated: a Pediatric Oncology Group study

This study was designed to test if the activity of a phase II agent, ifosfamide, would have been underestimated if it was tested exclusively in a population of children and young adults with recurrent osteosarcoma. The response rate to ifosfamide was compared in patients younger than 30 years of age with previously untreated osteosarcoma with metastases at diagnosis and/or unresectable primary tumors (stratum 1) with that of patients with recurrent osteosarcoma following adjuvant chemotherapy who were not previously exposed to ifosfamide (stratum 2). Evaluation of response was conducted 3 weeks after two courses of ifosfamide (2400 mg/m2 x 5 days) were administered 3 weeks apart. Nine of 33 (27%) evaluable patients in stratum 1 responded (1 complete and 8 partial responses) to ifosfamide. Among 30 evaluable patients in stratum 2, only 3 (10%) responded (1 complete and 2 partial responses; P = .04) Both groups of patients received equal doses of ifosfamide and experienced comparable toxicities. Results from this study suggest that the activity of new agents will be underestimated if tested in a population of heavily pretreated patients with recurrent disease. When possible, new chemotherapeutic agents should be tested in patients with a poor prognosis who have not been exposed to chemotherapy.