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Biomedical subjects

B McCormick

Publications and source records attributed to B McCormick.

At least 55 records · Page 3Linked to original sources
PubMed1996

External beam radiation therapy and retinoblastoma: long-term results in the comparison of two techniques.

PURPOSE: This study compares the long-term actuarial local control, eye conservation rate, survival, and ocular complications in children with retinoblastoma treated with two different external beam treatment techniques. METHODS AND MATERIALS: From 1979-1991, 182 eyes in 123 children (104 bilateral) received primary external beam radiation therapy. An anterior lens-sparing electron beam technique delivering 38 to 50 Gy in 2.5 Gy fractions was used in 67 eyes from 1979-1984 and a modified lateral beam technique, delivering 42 to 46 Gy in 2 Gy fractions, was used in 113 eyes from 1984-1991. These groups were balanced with respect to known prognostic variables. RESULTS: For Group I-III eyes, the 5- and 8-year local control was significantly improved using the modified lateral beam technique (84%) compared to (38%) using the anterior lens sparing technique (p < or = 0.0001). For Group IV-V eyes, the 5- and 8-year local control rates were not statistically different, despite a trend favoring the modified lateral beam technique. Survival endpoints including eye survival (no enucleation), cause-specific survival, and overall survival comparing the two treatment techniques were not significantly different. Overall, 22% of eyes developed cataracts. There was no difference between the two treatment groups in terms of cataract development. No eyes required enucleation for ocular complications. CONCLUSION: There is a significant improvement in local control using the modified lateral beam technique compared to an anterior lens-sparing approach for Group I-III eyes. However, there was no difference in survival end points between the two treatment techniques. The incidence of ocular complications using these two external beam techniques is acceptable.

Child↗
PubMed1996

The influence of older age on breast cancer treatment decisions and outcome.

PURPOSE: Information concerning the differences between older and younger women with breast cancer, treated with standard therapy, is lacking from many prospective series. The purpose of this study is to identify factors that influence treatment decisions and determine if women age 65 and older are treated differently than younger women. The outcomes of older women would then be compared to younger to determine if treatment differences influence outcome. METHODS AND MATERIALS: The records of 558 women with early invasive breast cancer who were treated with breast conserving surgery and radiation therapy were retrospectively reviewed. Four hundred thirty-two women under the age of 65 (range: 24-64) and 126 women age 65 and older (range: 65-85) were assessed for treatment differences including breast reexcision, extent of axillary dissection, extent of breast and nodal irradiation, and the use of chemotherapy or hormonal therapy. Differences in the treatment of the two groups were determined and the end points of local control, disease-free survival, and overall survival were compared. Median follow-up was 5.5 years. RESULTS: The two treatment groups had identical pathologic TNM staging with the exception that 21% of the older age group and 5% of the younger group did not undergo axillary dissection. Women age 65 and older were less likely to have a reexcision, extensive axillary dissection, chemotherapy, or nodal irradiation. They were more likely to receive hormonal therapy. Reexcision in older women was positively influenced by a family history of breast cancer and negatively influenced by a history of previous malignancy. None of the patients who were treated without and axillary dissection suffered a regional recurrence. Although local control was better in older patients, there were no differences in disease-free or overall survival for the two groups. DISCUSSION: The findings of this study reveal that older patients have significant treatment differences as compared to younger patients; however, despite these differences, similar local control and survival were achieved at 5 to 10 years. With the expected survival of older women increasing, the prospective evaluation of treatment options for older women should be considered.

Adult↗
PubMed1996

Fifteen-year results of breast-conserving surgery and definitive breast irradiation for the treatment of ductal carcinoma in situ of the breast.

PURPOSE: To determine the 15-year outcome for women with ductal carcinoma in situ (DCIS, intraductal carcinoma) of the breast treated with breast-conserving surgery followed by definitive breast irradiation. PATIENTS AND METHODS: An analysis was performed of 270 intraductal breast carcinomas in 268 women from 10 institutions in Europe and the United States. In all patients, breast-conserving surgery included complete gross excision of the primary tumor followed by definitive breast irradiation. When performed, pathologic axillary lymph node staging was node-negative (n=86). The median follow-up time was 10.3 years (range, 0.9 to 26.8). RESULTS: The 15-year actuarial overall survival rate was 87%, and the 15-year actuarial cause-specific survival rate was 96%. The 15-year actuarial rate of freedom from distant metastases was 96%. There were 45 local recurrences in the treated breast, and the 15-year actuarial rate of local failure was 19%. The median time to local failure was 5.2 years (range, 1.4 to 16.8). A number of clinical and pathologic parameters were evaluated for correlation with local failure, and none were predictive for local failure (all P > or = .15). CONCLUSION: The results from the present study demonstrate high rates of overall survival, cause-specific survival, and freedom from distant metastases following the treatment of DCIS of the breast using breast-conserving surgery and definitive breast irradiation. These results support the use of breast-conserving surgery and definitive breast irradiation for the treatment of DCIS of the breast.

Adult↗
PubMed1995

The influence of radiotherapy on cosmetic outcome after breast conservative surgery.

PURPOSE: The influence of radiotherapy in the cosmetic outcome after conservative surgery for breast cancer was evaluated using an objective method of calculating the asymmetry between the two breasts. METHODS AND MATERIALS: One hundred and one patients treated with the same conservative surgery were evaluated for cosmetic outcome. Sixty-one of them received external radiotherapy (50 + 10 Gy) to the residual breast; the remaining 40 underwent surgery only. The aspect of the patients' breasts was objectively assessed for symmetry by means of a computerized technique. A subjective assessment of the cosmetic outcome was performed both by physician and patient. These objective and subjective assessments were compared in the two groups treated with or without radiotherapy. RESULTS: The results obtained did not show significant differences in terms of cosmetic outcome in the two groups. Skin telangectasia was noted in two radiotherapy patients, while hypertrophic breast scars were only noted in six nonirradiated patients. CONCLUSIONS: We found that standard radiotherapy does not seem to influence the symmetry and the cosmetic results in breast conservative treatment when compared to a similar group of patients with the same quadrantectomy procedure and no radiotherapy.

Adult↗
PubMed1995

Effect of ocular implants of different materials on the dosimetry of external beam radiation therapy.

PURPOSE: To study the attenuation and scattering effects of ocular implants, made from different materials, on the dose distributions of a 6 MV photon beam, and 6, 9, and 12 MeV electron beams used in orbital radiotherapy. METHODS AND MATERIALS: Central axis depth-dose measurements were performed in a polystyrene phantom with embedded spherical ocular implants using film dosimetry of a 6 MV photon beam and electron beams of 6, 9, and 12 MeV energy. The isodose distributions were also calculated by a computerized treatment planning system using computerized tomography (CT) scans of a polystyrene phantom that had silicone, acrylic, and hydroxyapatite ocular implants placed into it. RESULTS: Electron beam dose distributions display distortions both on the measured and calculated data. This effect is most accentuated for the hydroxyapatite implants, for which the transmissions through ocular implants are on the order of 93% for the 6 MV photon beam, and range from 60% for 6 MeV electrons to 90% for 12 MeV electrons. CONCLUSION: We studied the effect of ocular implants of various materials, embedded in a polystyrene phantom, on the dose distributions of a 6 MV photon beam, and 6, 9, and 12 MeV electron beams. Our investigations show that while 6 MV photons experience only a few percent attenuation, lower energy electron beam with 60% transmission is not a suitable choice of treating tumors behind the ocular implants.

Colloids↗
PubMed1995

Improved survival in young women with breast cancer.

BACKGROUND: Young age has been hypothesized to be an adverse prognostic factor for women with breast cancer. This association, based on historical data, may not reflect recent advances in breast cancer management. METHODS: A retrospective study was conducted of all women age 30 or younger who underwent definitive operation at our institution for primary operable breast carcinoma during one of two consecutive 20-year periods (1950-1969 or 1970-1989). All cancers were restaged according to current staging criteria. Actuarial survival and recurrence-free survival rates from the two patient eras were compared with each other and with published statistics for older breast cancer patients. RESULTS: Eligibility criteria were met by 81 women from the 1950-1969 era and 146 women from the 1970-1989 era. Histologic diagnoses, tumor sizes, incidence of axillary nodal metastases, number of positive nodes, and American Joint Committee on Cancer stage at presentation were similarly distributed in the two eras. Despite these similarities, improved survival (p = 0.009) was observed in the later era. Local recurrences were also more common (p < 0.05) in the later era in association with less extensive resections. These local recurrences had an adverse impact on recurrence-free survival in the later era, but no concomitant decrease in overall survival was observed. Node-positive patients who received chemotherapy demonstrated a trend toward improved survival (p = 0.06) compared with node-positive patients who did not. Survival for patients in the later era was similar to that for older women as reported in other published series. CONCLUSIONS: The stage of presentation of breast cancer in women 30 years or younger appears unchanged from prior decades, but survival has improved in association with the use of less extensive surgical resections and the introduction of cytotoxic chemotherapy. With current treatment, primary operable breast cancer in young women appears to have a similar prognosis to breast cancer in older women.

Actuarial Analysis↗
PubMed1995

Radiation therapy for breast cancer.

As data bases mature, more in-depth analyses of results, with special attention to late dose and volume effects and second cancers, are appearing in the literature. In the continuing effort to minimize late effects, the importance of the boost dose is being reexamined, in relationship to the increasingly sophisticated margin information now available from most pathology laboratories. As well, patients are increasingly being grouped by various risk factors into subsets rather than receiving standard management as dictated by their stage of disease. This year the special needs of the elderly patient is being focused on, with regard to the need for dissecting the axilla and observations regarding the role of tamoxifen in both distant and local control.

Breast Neoplasms↗
PubMed1995

Controlled mold geometry for surgical deficit treatment planning.

The relatively precise placement of brachytherapy sources afforded by stereotactic frames for brain implants is not generally achievable for other sites, which lack the fixed geometry of the cranium and its contents. An exception is a source-containing rigid mold that delivers brachytherapy when inserted securely in a surgical defect. A technique has been developed in which an acrylic mold of the region to be treated is suspended in a demountable aluminum box, which is then filled to a suitable level with dental stone to form a casting that supports the mold and that can be removed intact. First, the box is aligned on a mill table and a ball mill is used to drill three parallel holes in the acrylic mold, with precisely known locations and depths and as widely separated as possible. The spherical air cavities that result from plugging these holes with ball-milled acrylic rods become reference markers in subsequent computed tomography (CT) scans. After optimum CT-coordinate locations have been planned for 125I seeds in catheters, they are transformed to mill coordinates using a matrix developed from the known marker coordinates in the two systems. Catheter holes are then drilled with the mold in the reassembled casting and box. The method has been used to treat both recurrent maxillary cancer and recurrent orbital rhabdomyosarcoma.

Biophysical Phenomena↗
PubMed1994

Salvage treatment for local recurrence following breast-conserving surgery and definitive irradiation for ductal carcinoma in situ (intraductal carcinoma) of the breast.

PURPOSE: The purpose of the present study is to evaluate the outcome of salvage treatment for local recurrence in the breast following the initial treatment of ductal carcinoma in situ (intraductal carcinoma) with breast-conserving surgery and definitive breast irradiation. METHODS AND MATERIALS: An analysis was performed of 42 local failures in the breast that occurred following the initial treatment of ductal carcinoma in situ (intraductal carcinoma) with breast-conserving surgery and definitive breast irradiation. At the time of the local recurrence, 23 cases (55%) showed invasive ductal carcinoma, and 19 cases (45%) showed intraductal carcinoma, one with associated Paget's disease. The surgical treatment at the time of local recurrence included mastectomy (n = 39), excision (n = 2), or other (n = 1). Adjuvant systemic therapy at the time of local recurrence included chemotherapy (n = 2), hormonal treatment (n = 7), both (n = 1), or none (n = 32). The median follow-up after salvage treatment was 3.7 years (mean = 4.0 years; range = 0.1-9.5 years). RESULTS: The 5-year actuarial outcome following salvage treatment for the 42 local recurrences showed an overall survival rate of 78% and a cause-specific survival rate of 84%. The 5-year actuarial rate of freedom from distant metastases was 86%. None of the patients with histology of the local recurrence of intraductal carcinoma or with detection of the local recurrence with mammographic findings only developed distant metastatic disease after salvage treatment. The 5-year actuarial rate of freedom from chest wall recurrence following salvage mastectomy was 92%. All three of the patients who developed chest wall recurrence following salvage mastectomy also developed distant metastatic disease. CONCLUSIONS: These results demonstrate that local recurrences following the initial treatment of ductal carcinoma in situ with breast-conserving surgery and definitive breast irradiation can be salvaged with high rates of survival, freedom from distant metastases, and freedom from chest wall recurrence. The results of salvage treatment support the use of breast-conserving surgery and definitive breast irradiation for the initial management of ductal carcinoma in situ of the breast.

Adult↗
PubMed1994

Prone position breast irradiation.

PURPOSE: An alternative technique for irradiating the breast following breast conserving surgery is described. METHODS AND MATERIALS: The technique utilizes the prone position and has been developed to improve the dose distribution within the breast and reduce the volume of normal tissues irradiated during whole breast treatment. Improvements in the dosimetry of breast irradiation are obtained through the optimization of the shape of the breast and result in a reduction in the magnitude of high-dose regions and isodose gradients at the base of the breast. RESULTS: The high dose region at the base of the breast, without lung correction, generally ranges from 116-118% for large breasted women treated in the supine position. These high dose regions are reduced to 102-103% for the same women treated in the prone position. Irradiation of the heart, lungs, chest wall and contralateral breast are minimized with this technique. The improvements appear to benefit women with large breasts, pendulous breasts, large separations and/or irregularly shaped chest contours. CONCLUSION: The prone position technique takes advantage of the reproducibility characteristics of the supine position technique and combines them with the homogeneity and normal tissue-sparing characteristics of the lateral decubitus position technique. Prone position breast irradiation appears to be a simple and effective alternative to irradiation of the breast in the conventional supine position when the supine position is likely to result in unacceptable dose inhomogeneity or significant doses to normal tissues.

Breast↗
PubMed1994

Effects of beam modifiers and immobilization devices on the dose in the build-up region.

PURPOSE: To analyze the effect that immobilization devices used in conjunction with beam modifiers may have on the dose to the skin and build-up region. METHODS AND MATERIALS: Central axis depth dose measurements were made in a polystyrene phantom in the build-up regions using the 6 and 15 MV photon beams, at two different source-to-phantom distances, and various field sizes. The effects of acrylic blocking trays, lead wedges, and cerrobend blocks were assessed in conjunction with the enhancement of dose in the build-up region due to immobilizing devices using plaster and thermoplastic casting materials of different thicknesses. RESULTS: For the 6 MV photons, solid (3 mm) thermoplastic casting material was found to have the greatest effect on surface dose: for a 12 x 12 cm field we measured 79% of maximum dose when treating through the material versus 22% of maximum dose when no beam modifiers or immobilization devices are used. Measurements were also made to evaluate the effect of the immobilization of patients receiving three-dimensional conformal treatments using a 15 MV photon beam. CONCLUSIONS: The relevance of these results to treatments in the pelvis, breast, and head and neck regions is discussed. For 6 MV beams, special consideration should be given if the need arises to treat through the immobilization device, as unacceptable skin reactions may result.

Dose-Response Relationship, Radiation↗
PubMed1994

Selection criteria for breast conservation. The impact of young and old age and collagen vascular disease.

BACKGROUND: Selection criteria applicable to women desiring breast-conserving surgery and radiation for early invasive breast cancer have evolved over the last decade. The presence of active collagen vascular disease has emerged as a contraindication for this treatment. The roles of both young and old age have been debated by many authors, although a growing body of literature supports the impact of age on both local control and disease free survival. METHODS: This is a review of the literature addressing these selection criteria. RESULTS: A consensus exists regarding the impact of preexisting collagen vascular disease on the anticipated complications with breast-conserving radiation, despite small numbers reported. A young age, although not always a statistically significant factor, emerges as a consistent predictor for both local and distant failures. This is true not only for patients who opt for breast conservation but also those who are treated with mastectomy. To the contrary, preliminary data suggests that older age is emerging as a predictor for improved local and regional control. CONCLUSIONS: Preexisting collagen vascular disease is a contraindication for the use of breast-conserving radiation and surgery. Extremes of age must be considered in terms of recommending not so much a specific local regional treatment, but an overall strategy. For the very young patient with breast cancer, more aggressive systemic therapy should be considered in addition to the appropriate local regional therapy. For the elderly, preliminary pilot studies suggest that tamoxifen may play a role in local as well systemic control, perhaps opening the door for future trials examining the need for radiation in selected elderly patients.

Adult↗