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Dive into the research topics where Mark C. Gebhardt is active.

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Featured researches published by Mark C. Gebhardt.


Clinical Orthopaedics and Related Research | 1993

A system for the functional evaluation of reconstructive procedures after surgical treatment of tumors of the musculoskeletal system.

William F. Enneking; William K. Dunham; Mark C. Gebhardt; Martin Malawar; Douglas J. Pritchard

The need for a standardized system of end result reporting of various surgical alternatives after limb salvaging and ablative procedures for musculoskeletal tumors was clearly recognized during the first International Symposium on Limb Salvage (ISOLS) in 1981. During the ensuing four biannual symposia, there has been an ongoing developmental experience with a system extensively field tested in 1989 by the Musculoskeletal Tumor Society (MSTS). This system of functional evaluation has been adopted by the MSTS and ISOLS for their joint studies and program presentation. In brief, the system assigns numerical values (0-5) for each of six categories: pain, and function and emotional acceptance in upper and lower extremities; supports, and walking and gait in the lower extremity; and hand positioning, and dexterity and lifting ability in the upper extremity. Demographic information and a patient satisfaction component is included. A numerical score and percent rating is calculated to allow for comparison of results. The system has been field tested in 220 patients with low (+/-) interobserver variability. It was well accepted by the participants, and its usage is recommended by the MSTS to facilitate valid comparative end result studies of musculoskeletal tumor reconstructions.


Molecular and Cellular Biology | 1990

P53 FUNCTIONS AS A CELL CYCLE CONTROL PROTEIN IN OSTEOSARCOMAS

Lisa Diller; J Kassel; Craig E. Nelson; Magdalena A. Gryka; Litwak Gj; Mark C. Gebhardt; B Bressac; Mehmet Ozturk; S J Baker; Bert Vogelstein

Mutations in the p53 gene have been associated with a wide range of human tumors, including osteosarcomas. Although it has been shown that wild-type p53 can block the ability of E1a and ras to cotransform primary rodent cells, it is poorly understood why inactivation of the p53 gene is important for tumor formation. We show that overexpression of the gene encoding wild-type p53 blocks the growth of osteosarcoma cells. The growth arrest was determined to be due to an inability of the transfected cells to progress into S phase. This suggests that the role of the p53 gene as an antioncogene may be in controlling the cell cycle in a fashion analogous to the check-point control genes in Saccharomyces cerevisiae.


Journal of Bone and Joint Surgery, American Volume | 1998

Percutaneous radiofrequency coagulation of osteoid osteoma compared with operative treatment.

Daniel I. Rosenthal; Francis J. Hornicek; Michael W. Wolfe; L. Candace Jennings; Mark C. Gebhardt; Henry J. Mankin

Osteoid osteoma, a benign bone tumor, has traditionally been treated with operative excision. A recently developed method for percutaneous ablation of the tumor has been proposed as an alternative to operative treatment. The relative outcomes of the two approaches to treatment have not previously been compared, to our knowledge. The rates of recurrence and of persistent symptoms were compared in a consecutive series of eighty-seven patients who were managed with operative excision and thirty-eight patients who were managed with percutaneous ablation with radiofrequency. Patients who had a spinal lesion were excluded. The minimum duration of follow-up was two years. There was a recurrence, defined as the need for subsequent intervention, after operative treatment in six (9 per cent) of sixty-eight patients who had been managed for a primary lesion and in two of nineteen who had been managed for a recurrent lesion. The average length of the hospital stay was 4.7 days for the patients who had a primary lesion and 5.1 days for those who had a recurrent lesion. There was a recurrence after percutaneous treatment in four (12 per cent) of thirty-three patients who had been managed for a primary lesion and in none of five who had been managed for a recurrent lesion. The average length of the hospital stay was 0.2 day for these thirty-eight patients. With the numbers available, we could detect no significant difference between the two treatments with regard to the rate of recurrence. The rate of persistent symptoms (that is, symptoms that did not necessitate additional treatment) was greater than the rate of recurrence. According to responses to a questionnaire, eight (30 per cent) of twenty-seven patients had persistent symptoms after operative treatment and six (23 per cent) of twenty-six patients had persistent symptoms after percutaneous treatment with radiofrequency. Two patients had complications after operative excision, necessitating a total of five additional operations. There were no complications associated with the percutaneous method. The results of the present study suggest that percutaneous ablation with radiofrequency is essentially equivalent to operative excision for the treatment of an osteoid osteoma in an extremity. The percutaneous method is preferred for the treatment of extraspinal osteoid osteoma because it generally does not necessitate hospitalization, it has not been associated with complications, and it is associated with a rapid convalescence.


Journal of Clinical Oncology | 2005

Osteosarcoma: A Randomized, Prospective Trial of the Addition of Ifosfamide and/or Muramyl Tripeptide to Cisplatin, Doxorubicin, and High-Dose Methotrexate

Paul A. Meyers; Cindy L. Schwartz; Mark Krailo; Eugenie S. Kleinerman; Donna L. Betcher; Mark Bernstein; Ernest U. Conrad; William S. Ferguson; Mark C. Gebhardt; Allen M. Goorin; Michael B. Harris; John H. Healey; Andrew G. Huvos; Michael P. Link; Joseph Montebello; Helen Nadel; Michael L. Nieder; Judith K. Sato; Gene P. Siegal; Michael A. Weiner; Robert J. Wells; Lester E. Wold; Richard B. Womer; Holcombe E. Grier

PURPOSE To determine whether the addition of ifosfamide and/or muramyl tripeptide (MTP) encapsulated in liposomes to cisplatin, doxorubicin, and high-dose methotrexate (HDMTX) could improve the probability for event-free survival (EFS) in newly diagnosed patients with osteosarcoma (OS). PATIENTS AND METHODS Six hundred seventy-seven patients with OS without clinically detectable metastatic disease were treated with one of four prospectively randomized treatments. All patients received identical cumulative doses of cisplatin, doxorubicin, and HDMTX and underwent definitive surgical resection of the primary tumor. Patients were randomly assigned to receive or not to receive ifosfamide and/or MTP in a 2 double dagger 2 factorial design. The primary end point for analysis was EFS. RESULTS Patients treated with the standard arm of therapy had a 3-year EFS of 71%. We could not analyze the results by factorial design because we observed an interaction between the addition of ifosfamide and the addition of MTP. The addition of MTP to standard chemotherapy achieved a 3-year EFS rate of 68%. The addition of ifosfamide to standard chemotherapy achieved a 3-year EFS rate of 61%. The addition of both ifosfamide and MTP resulted in a 3-year EFS rate of 78%. CONCLUSION The addition of ifosfamide in this dose schedule to standard chemotherapy did not enhance EFS. The addition of MTP to chemotherapy might improve EFS, but additional clinical and laboratory investigation will be necessary to explain the interaction between ifosfamide and MTP.


Journal of Clinical Oncology | 2008

Osteosarcoma: The Addition of Muramyl Tripeptide to Chemotherapy Improves Overall Survival—A Report From the Children's Oncology Group

Paul A. Meyers; Cindy L. Schwartz; Mark Krailo; John H. Healey; Mark Bernstein; Donna L. Betcher; William S. Ferguson; Mark C. Gebhardt; Allen M. Goorin; Michael B. Harris; Eugenie S. Kleinerman; Michael P. Link; Helen Nadel; Michael L. Nieder; Gene P. Siegal; Michael A. Weiner; Robert J. Wells; Richard B. Womer; Holcombe E. Grier

PURPOSE To compare three-drug chemotherapy with cisplatin, doxorubicin, and methotrexate with four-drug chemotherapy with cisplatin, doxorubicin, methotrexate, and ifosfamide for the treatment of osteosarcoma. To determine whether the addition of muramyl tripeptide (MTP) to chemotherapy enhances event-free survival (EFS) and overall survival in newly diagnosed patients with osteosarcoma. PATIENTS AND METHODS Six hundred sixty-two patients with osteosarcoma without clinically detectable metastatic disease and whose disease was considered resectable received one of four prospectively randomized treatments. All patients received identical cumulative doses of cisplatin, doxorubicin, and methotrexate and underwent definitive surgical resection of primary tumor. Patients were randomly assigned to receive or not to receive ifosfamide and/or MTP in a 2 x 2 factorial design. The primary end points for analysis were EFS and overall survival. RESULTS In the current analysis, there was no evidence of interaction, and we were able to examine each intervention separately. The chemotherapy regimens resulted in similar EFS and overall survival. There was a trend toward better EFS with the addition of MTP (P = .08). The addition of MTP to chemotherapy improved 6-year overall survival from 70% to 78% (P = .03). The hazard ratio for overall survival with the addition of MTP was 0.71 (95% CI, 0.52 to 0.96). CONCLUSION The addition of ifosfamide to cisplatin, doxorubicin, and methotrexate did not enhance EFS or overall survival for patients with osteosarcoma. The addition of MTP to chemotherapy resulted in a statistically significant improvement in overall survival and a trend toward better EFS.


Journal of Bone and Joint Surgery, American Volume | 1988

Infection in bone allografts. Incidence, nature, and treatment.

C F Lord; Mark C. Gebhardt; William W. Tomford; Henry J. Mankin

Of 283 patients who had a massive allograft of bone, an infection developed in thirty-three (11.7 per cent). To assess the frequency and identify the co-morbid and predisposing factors of this devastating complication, we compared demographic data for the infected and non-infected patients. Comparison of mean age, type of graft, anatomical site of the procedure, and stage of the tumor yielded no significant differences. Multiple-regression analysis of a subgroup of eighty-two patients who had a distal femoral graft showed a correlation between infection and factors that are associated with more extensive surgery (more loss of bone, soft tissue, or skin) or with multiple operations. Approximately 30 per cent of the patients who had an infected allograft had no co-morbid or predisposing factors that could be statistically correlated with an increased risk for infection. Gram-positive organisms were the most common cause of infection, with twelve infections (36 per cent) being due to Staphylococcus epidermidis. Six patients had a single gram-negative organism and nine had mixed flora. The final result in the thirty-three patients who had an infected allograft was poor compared with that of the over-all series and of the uninfected patients. Twenty-seven infected allografts (82 per cent) were considered to be failures of treatment because amputation of the limb or resection of the graft was required to control the infection.(ABSTRACT TRUNCATED AT 250 WORDS)


The New England Journal of Medicine | 1992

Germline Mutations of the p53 Tumor-Suppressor Gene in Children and Young Adults with Second Malignant Neoplasms

David Malkin; Kent W. Jolly; Noële Barbier; A. Thomas Look; Stephen H. Friend; Mark C. Gebhardt; Tone Ikdahl Andersen; Anne Lise Børresen; Frederick P. Li; Judy Garber; Louise C. Strong

BACKGROUND Acquired mutations in the p53 tumor-suppressor gene have been detected in several human cancers, including colon, breast, and lung cancer. Inherited mutations (transmitted through the germline) of this gene can underlie the Li-Fraumeni syndrome, a rare familial association of breast cancer in young women, childhood sarcomas, and other malignant neoplasms. We investigated the possibility that p53 mutations in the germline are associated with second primary cancers that arise in children and young adults who would not be considered as belonging to Li-Fraumeni families. METHODS Genomic DNA was extracted from the blood leukocytes of 59 children and young adults with a second primary cancer. The polymerase chain reaction, in combination with denaturant-gel electrophoresis and sequencing, was used to identify p53 gene mutations. RESULTS Mutations of p53 that changed the predicted amino acid sequence were identified in leukocyte DNA from 4 of the 59 patients (6.8 percent). In three cases, the mutations were identical to ones previously found in the p53 gene. The fourth mutation was the first germline mutation to be identified in exon 9, at codon 325. Analysis of leukocyte DNA from close relatives of three of the patients indicated that the mutations were inherited, but cancer had developed in only one parent at the start of the study. CONCLUSIONS These findings identify an important subgroup of young patients with cancer who carry germline mutations in the p53 tumor-suppressor gene but whose family histories are not indicative of the Li-Fraumeni syndrome. The early detection of such mutations would be useful not only in treating these patients, but also in identifying family members who may be at high risk for the development of tumors.


Journal of Bone and Joint Surgery, American Volume | 1999

Chondrosarcoma of Bone: An Assessment of Outcome*

Francis Y. Lee; Henry J. Mankin; Gertrude Fondren; Mark C. Gebhardt; Dempsey S. Springfield; Andrew E. Rosenberg; L. Candace Jennings

BACKGROUND The data on 227 patients who had been managed for a chondrosarcoma at one institution were reviewed to determine the nature of the lesions, the predictors of outcome, and whether there were any ways to change the treatment approaches to improve the results. METHODS The patients were followed for a mean duration of six years (range, three to twenty-five years). The mean age of the patients was forty-seven years (range, nine to eighty-four years). The most prevalent sites of the tumors were the femur (seventy-eight), the pelvis (fifty-one), and the humerus (thirty-nine). The tumors were divided into two groups according to histological grade. Eighty-six tumors (sixteen atypical enchondromas and seventy grade-1 chondrosarcomas) that were locally destructive but were associated with a low likelihood of metastasis were considered to be low-grade. The remaining 141 lesions, which were locally destructive, potentially metastatic, and capable of causing death, were thought to be high-grade. One hundred and three of these 141 lesions were grade 2, and thirty-eight were grade 3 (eighteen of the thirty-eight were grade 3 only, and twenty were both grade 3 and dedifferentiated). Two hundred and twenty-four patients were managed with resection and a limb-sparing procedure; the remaining three patients had an amputation. Postoperative adjuvant radiation was used for fifty-six patients; chemotherapy, for thirty-five; and both radiation and chemotherapy, for nineteen. Flow cytometric patterns were analyzed for 105 patients. RESULTS The patients who had a high-grade tumor were older than those who had a low-grade tumor (mean age [and standard deviation], 50+/-17.0 years compared with 40+/-15.9 years; p < 0.001). Pathological fracture, metastasis, local recurrence, and death were more prevalent in the group that had a high-grade lesion (p < 0.001). Predictors of metastasis and death in that group of patients included local recurrence, a pelvic location of the tumor, a tumor that was more than 100 cubic centimeters in size, a ploidic abnormality (aneuploidy coupled with a high mean DNA index), a histological grade of 3, and a dedifferentiated type of tumor (p < 0.001). CONCLUSIONS Although the data are suggestive, with the numbers available for study we could not detect a significant difference in the rates of pulmonary metastasis and death between the patients who had a grade-3 lesion and those who had a grade-3 lesion that was also dedifferentiated. However, the interval between diagnosis and death was 32+/-22.8 months for the patients who had a grade-3 lesion compared with 5+/-3.7 months for those who had a grade-3 lesion that was also dedifferentiated (p < 0.001). Overall, patients who had had a resection with wide margins (margins extending outside the reactive zone) had a longer duration of survival than did those who had had a so-called marginal resection (margins extending outside the tumor but within the reactive zone) or an intralesional resection (margins within the lesion) (p < 0.04). Adjunctive chemotherapy or radiation, or both (which, it must be noted, was used, without a protocol, in a relatively small number of patients), after an intralesional resection, for recurrent disease, or for distant metastasis did not appear to alter the outcome.


Journal of Bone and Joint Surgery, American Volume | 1994

Recurrence of giant-cell tumors of the long bones after curettage and packing with cement.

Richard J. O'Donnell; Springfield Ds; H K Motwani; John E. Ready; Mark C. Gebhardt; Henry J. Mankin

The nine-year experience with sixty patients who had had a giant-cell tumor of a long bone was reviewed to determine the rate of recurrence after treatment with curettage and packing with polymethylmethacrylate cement. The demographic characteristics, including the age and sex of the patient and the site of the tumor, were similar to those that have been reported for other large series. An average of four years (range, two to ten years) after the operation, the over-all rate of initial local recurrence was 25 per cent (fifteen of sixty patients). Patients who had had a tumor of the distal aspect of the radius had a higher rate of recurrence (five of ten) than those who had had a tumor of the proximal aspect of the tibia (seven [28 per cent] of twenty-five) or of the distal part of the femur (three [13 per cent] of twenty-three). Higher rates of recurrence were also noted for patients who had had a pathological fracture (three of six), those who had had a Stage-III tumor according to the classification of Campanacci et al. (six of sixteen), and those who had not had adjuvant treatment with either a high-speed burr or phenol (eight of nineteen). Patients who had had an initial recurrence after packing with cement had a low rate of secondary recurrence when the initial recurrence had been treated with a wide resection or a second intralesional procedure (zero of ten and one of five patients, respectively), after an average of three years (range, ten months to eight years). No patient had a multicentric tumor or metastasis.(ABSTRACT TRUNCATED AT 250 WORDS)


Journal of Bone and Joint Surgery, American Volume | 1990

Fractures of allografts. Frequency, treatment, and end-results.

B H Berrey; C F Lord; Mark C. Gebhardt; Henry J. Mankin

One of the major complications of implantation of a massive frozen cadaveric allograft in the treatment of a tumor is fracture of the allograft. To determine the incidence, risk factors, appropriate management, and results of treatment of this complication, the records of the Orthopaedic Oncology Unit of the Massachusetts General Hospital were reviewed. Forty-three patients were identified in whom a tumor had been treated with an allograft that had subsequently fractured. The over-all incidence of fracture was almost 16 per cent. When the several risk factors (age and sex of the patient, stage and site of the lesion, and so on) for the forty-three patients who had a fracture were compared with those for the rest of the series, the only correlation was the incidence of non-union at the site of the host-donor junction, which was significantly higher in the patients who had a fracture. The mean time to fracture was 28.6 months after the operation. Three types of fractures occurred: Type I (two patients), rapid dissolution of the graft; Type II (twenty-two patients), fracture of the shaft, which was observed more frequently in male patients and which occurred a mean of 27.6 months after the operation; and Type III (nineteen patients), fragmentation of the joint, which usually occurred later (a mean of 31.6 months postoperatively) and was found more frequently in female patients.(ABSTRACT TRUNCATED AT 250 WORDS)

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Mark Krailo

University of Southern California

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