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Biomedical subjects

R S Bell

Publications and source records attributed to R S Bell.

7 recordsLinked to original sources
PubMed1992

Chemotherapy and surgery in a murine osteosarcoma.

Surgical and chemotherapeutic effects on pulmonary metastatic disease were evaluated in the MGH-OGS murine osteosarcoma. The tumor responded to three sequential injections of doxorubicin with prolonged growth delay but cisplatin administration (although given in doses sufficient to cause weight loss and significant mortality) was not effective in controlling local disease progression. Using a protocol with three injections of doxorubicin (0.006 mg/g of body weight), it was observed that disease-free survival was enhanced when one of the three doses of doxorubicin was given at the time of surgery (perioperatively). By marginally resecting the primary tumor and permitting its regrowth, a model was developed with recurrent primary and metastatic disease present simultaneously. It was observed in this model that amputation or resection of the recurrent primary lesion resulted in pulmonary metastatic growth acceleration. Using this recurrent primary tumor model, doxorubicin's effect on pulmonary metastatic lesions was enhanced when the drug was given at the time of amputation.

Animals↗
PubMed1992

Management of long-term postirradiation periclavicular complications.

Four cases of periclavicular postirradiation sarcoma and two cases of clavicular osteoradionecrosis with pathologic fractures are reported. All six cases presented more than 10 years after irradiation for breast cancer (five) or nasopharyngeal carcinoma (one). A review of radiotherapy received showed that they were subjected to unconventional radiation schedules (hypofractionation or high dose per fraction treatment). An approach to diagnosis and management of periclavicular lesions arising long after therapeutic irradiation is presented and the unique problems encountered with periclavicular surgery are discussed.

Aged↗
PubMed1991

Functional outcome in patients treated with surgery and irradiation for soft tissue tumours.

One hundred five consecutive patients underwent surgical resection and adjuvant irradiation in treatment of soft tissue sarcoma or aggressive fibromatosis. All patients were entered in a prospective study evaluating functional outcome and 88 patients were examined at 12 months following surgery. Outcome was characterized using the Enneking system as well as documenting employment/recreational status and limb edema. Sixty-eight of 88 patients had functional scores of 21 or better (out of a possible total of 35). Forty-four patients were serially evaluated at 12 and 24 months and there was no difference in their outcome at the 2 time points. Univariate analysis demonstrated that large tumour size, postoperative complications, and neural sacrifice were associated with poor functional outcome.

Adolescent↗
PubMed1991

Preoperative and postoperative irradiation of soft tissue sarcomas: effect of radiation field size.

For the treatment of soft tissue sarcomas it has frequently been staged but not quantitatively demonstrated, that the volume irradiated is smaller when irradiation is given preoperatively as compared to postoperatively. In this study the field size used for preoperative irradiation was compared with that necessary in the same patient had the radiation been given postoperatively. Twenty-six patients with soft tissue sarcomas of the extremity, groin, and shoulder girdle who had received preoperative irradiation were resimulated following surgery to determine the size of the postoperative field. The simulation was performed by a physician not involved in the preoperative treatment planning. Preoperatively a radial margin of 5 cm around the tumor was used for low and intermediate grade and 7 cm for high grade sarcomas. Postoperatively the same margins were used but around the surgical field. Twelve patients underwent a wide resection and 14 patients a resection followed by vascularized tissue transfer to the surgical bed. The median follow-up was 22 months (range 13-46). No local recurrences and two cases of distant metastasis were observed. Independently of surgical procedure and tumor grade, the size of the preoperative radiation field and number of joints included in the field were significantly smaller than that of postoperative radiation (p less than 0.001). In two patients preoperatively and four patients postoperatively, the radiation field involved the whole circumference of the limb. Provided that equivalent radiation time-dose-fraction parameters are used and that the complication rate is proportional to the radiation field size, late complications may be less after preoperative irradiation than after post-operative irradiation.

Adolescent↗
PubMed1991

Fractures following limb-salvage surgery and adjuvant irradiation for soft-tissue sarcoma.

In a prospective study, consecutive patients were treated for soft-tissue sarcoma (STS) by wide resection and adjuvant irradiation. Twelve patients had resection of bone to achieve a tumor free margin; five of these patients were left with lower extremity open segmental cortical defects in the high-dose radiation field. Four of the five patients with cortical defects suffered a fracture through the defect more than six months after surgery. Only one of 71 patients not treated with bony resection suffered a late fracture. Patients requiring bony cortex resection for STS of the lower extremity should be considered at risk for late fracture if adjuvant irradiation is prescribed.

Adult↗
PubMed1978

Efficacy...what's that??

We need to develop techniques for measuring the usefulness of medical services. If resources are limited, and we cannot do all the diagnostic tests we would like to do, we must be able to select those that are most useful. To do this we need to known how to weigh benefits against risks and how to measure the worth of a given outcome. This article discusses efficacy, in diagnosis, management, and outcome. Diagnostic efficacy of a test is measured by its ability to change the probability of disease (pre- versus post-test likelihood). Management efficacy is a measure of how the test changes patient management. Outcome efficacy, which may take years to evaluate, is the ultimate yardstick of usefulness. Even though there are many problems in estimating the likelihood of a disease (subjectivity, varying terminology, etc.), physicians can make reasonably close estimates, as shown by the American College of Radiology's Efficacy Study, which analyzed the diagnostic process in 9000 cases. Efficacy studies may be a mixed blessing, however, as they may result in overly strict criteria and sweeping economic changes. They may be ignored because of the difficulty in following the "perfect" protocol for a given clinical situation, and it remains to be shown that they themselves are efficacious. Nevertheless, we are finally coming to grips with the question of how useful our tests are in patient management.

Cost-Benefit Analysis↗