Biomedical subjects

J D Forman

Publications and source records attributed to J D Forman.

At least 19 recordsLinked to original sources

PubMed2006

Compact multileaf collimator for conformal and intensity modulated fast neutron therapy: electromechanical design and validation.

The electromechanical properties of a 120-leaf, high-resolution, computer-controlled, fast neutron multileaf collimator (MLC) are presented. The MLC replaces an aging, manually operated multirod collimator. The MLC leaves project 5 mm in the isocentric plane perpendicular to the beam axis. A taper is included on the leaves matching beam divergence along one axis. The 5-mm leaf projection width is chosen to give high-resolution conformality across the entire field. The maximum field size provided is 30 x 30 cm2. To reduce the interleaf transmission a 0.254-mm blocking step is included. End-leaf steps totaling 0.762 mm are also provided allowing opposing leaves to close off within the primary radiation beam. The neutron MLC also includes individual 45 degrees and 60 degrees automated universal tungsten wedges. The automated high-resolution neutron collimation provides an increase in patient throughput capacity, enables a new modality, intensity modulated neutron therapy, and limits occupational radiation exposure by providing remote operation from a shielded console area.

Electronics, Medical↗

PubMed2001

The 1989 patterns of care study for prostate cancer: five-year outcomes.

PURPOSE: Five-year results from the 1989 patterns of care study (PCS) for prostate cancer are now ready for analysis. The PCS was initiated to determine national averages for treatments and examine outcomes prospectively; the 1989 prostate study is the first to have collected pre- and post-treatment serum PSA data. METHODS AND MATERIALS: Six hundred patients treated with radiotherapy with curative intent for prostate cancer at 71 separate institutions in the year 1989 made up the study population. Three hundred ninety-one cases were fully analyzable. Pretreatment patient and tumor characteristics were as follows: of the 391 analyzable, 255 had pretreatment PSA values obtained, and 245 had a Gleason's sum (GS) reported. Three hundred fifty-eight were Caucasian, 24 African-American, and 3 Hispanic (also 6 unknown). One hundred three patients had PSA < 10, 60 had PSA 10-19, and 92 presented with PSA >20. Ninety-seven patients were from Radiation Therapy Oncology Group (RTOG), Community Cancer Centers (CCC), or teaching institutions; 141 patients were from other hospital-based, nonteaching institutions; and 153 were from freestanding radiation oncology facilities. Seventy-one patients were T1, 203 T2, and 100 T3/4. Twenty-four out of 391 patients also received neoadjuvant hormone therapy. Survival curves were constructed using Kaplan-Meier methods, and differences between groups were tested for significance using the log-rank test. For cumulative incidence curves, Gray's test was used to investigate failure distributions between groups. The variables entering Cox model for multivariate analysis included age, race, T stage, pretreatment PSA, and GS. A patient was considered a PSA failure if the treating radiation oncologist reported it as such. RESULTS: With a median follow-up of 5.7 years, the 5-year biochemical no evidence of disease (bNED) and overall survival were 56% and 79% respectively for Stage T1, 52% and 81% for T2, and 36% and 63% for Stages T3 and T4 combined. As expected, higher pretreatment PSA, GS, and T stage were all prognostic of poorer outcome. On univariate analysis, bNED survival was adversely impacted by T stage (p = 0.009), pretreatment PSA (p = 0.0035), and by the GS (p = 0.0038). Cause-specific failure was significantly lower for higher T stage (p = 0.014), GS (p = 0.001), and also pretreatment PSA (p = 0.0004). Overall survival was significantly lower in patients with higher T stage (p = 0.047) or GS (p = 0.0191), but not pretreatment PSA (p = 0.284). On multivariate analysis, pretreatment PSA was found to be statistically significant in association with bNED survival, and GS was associated with overall survival, cause-specific survival, and distant metastasis. Few late complications were reported: 13/391 and 13/391 Grade 2-3 gastrointestinal (GI) and genitourinary (GU) complications respectively, with two patients having required surgery with or without a permanent colostomy. CONCLUSION: For a representative cross-section of institutions in the United States, radiotherapy achieved high rates of bNED and CSS in selected groups of prostate cancer patients. When studied retrospectively, increased pretreatment PSA was a strong predictor of both biochemical failure and death due to prostate cancer. New strategies for patients with high-stage, high-grade tumors and/or pretreatment PSA >20 deserve testing.

Aged↗

PubMed2001

Attenuation and activation characteristics of steel and tungsten and the suitability of these materials for use in a fast neutron multileaf collimator.

A computer controlled multileaf collimator (MLC) is being designed to replace the multirod collimator (MRC) at present used to shape the d(48.5) + Be neutron beam from the Harper Hospital superconducting cyclotron. The computer controlled MLC will improve efficiency and allow for the future development of intensity modulated radiation therapy with neutrons. The existing MRC uses tungsten rods, while the new MLC will use steel as the leaf material. In the current study the attenuation and activation characteristics of steel are compared with those of tungsten to ensure that (a) the attenuation achieved in the MLC is at least equivalent to that of the existing MRC, and (b) that the activation of the steel will not result in a significant change in the activation levels within the treatment room. The latter point is important since personnel exposure (particularly to the radiation therapy technologists) from induced radioactivity must be minimized. Measurement of the neutron beam attenuation in a broad beam geometry showed that a 30 cm thick steel leaf yielded 2.5% transmission. This compared favorably with the 4% transmission obtained with the existing MRC. Irradiation of steel and tungsten samples at different depths in a 30 cm steel block indicated that the activation of steel should be no worse than that of tungsten.

Biophysical Phenomena↗

PubMed2001

Neutron or photon irradiation for prostate tumors: enhancement of cytokine therapy in a metastatic tumor model.

We have shown that implantation of human prostate carcinoma PC-3 cells in the prostates of nude mice led to the formation of prostate tumors with metastases to para-aortic lymph nodes. We found that day 6 prostate tumors were responsive to systemic injections of interleukin 2 (IL-2) therapy. We have now investigated the combination of primary tumor irradiation and IL-2 for metastatic prostate cancer in this preclinical tumor model. The effect of neutron radiation was compared with that of photon radiation. Advanced prostate tumors (approximately 0.4 cm) were irradiated, and a day later, mice were treated with systemic IL-2 for three weekly cycles. In separate experiments, mice were either sacrificed on day 30 to assess prostate tumor size and tumor histology or followed for survival. A dose-dependent inhibition of prostate tumor growth was caused either by photons or neutrons, but neutrons were more effective than photons with a relative biological effectiveness of 2. The tumor inhibition obtained with 250 cGy neutrons and 500 cGy photons was significant (>75%) and was further increased (> or = 90%) by addition of IL-2 therapy. In survival studies, the combination of radiation and IL-2 showed a significant survival advantage compared with untreated mice (P < or = 0.005) or radiation alone (P < or = 0.003) and an increase in median survival compared with IL-2 alone. Histologically, the combined regimen resulted in a greater degree of tumor destruction, inflammatory response, and vascular damage than that observed with each modality alone. After this combined treatment, no tumor was histologically detected in the para-aortic lymph nodes of these mice, and the lymph nodes were significantly smaller. These findings showed that primary tumor irradiation, either with neutrons or photons, enhanced IL-2 therapeutic effect for the treatment of advanced prostate cancer. This combined modality induced an antitumor response that controlled the growth of prostate tumors and their metastases.

Adenocarcinoma↗

PubMed2001

Genistein potentiates the radiation effect on prostate carcinoma cells.

We have shown previously that genistein, the major isoflavone in soybean, inhibited the growth of human prostate cancer cells in vitro by affecting the cell cycle and inducing apoptosis. To augment the effect of radiation for prostate carcinoma, we have now tested the combination of genistein with photon and neutron radiation on prostate carcinoma cells in vitro. The effects of photon or neutron radiation alone or genistein alone or both combined were evaluated on DNA synthesis, cell growth, and cell ability to form colonies. We found that neutrons were more effective than photons for the killing of prostate carcinoma cells in vitro, resulting in a relative biological effectiveness of 2.6 when compared with photons. Genistein at 15 microM caused a significant inhibition in DNA synthesis, cell growth, and colony formation in the range of 40-60% and potentiated the effect of low doses of 200-300 cGy photon or 100-150 cGy neutron radiation. The effect of the combined treatment was more pronounced than with genistein or radiation alone. Our data indicate that genistein combined with radiation inhibits DNA synthesis, resulting in inhibition of cell division and growth. Genistein can augment the effect of neutrons at doses approximately 2-fold lower than photon doses required to observe the same efficacy. These studies suggest a potential of combining genistein with radiation for the treatment of localized prostate carcinoma.

Antineoplastic Agents↗

PubMed2000

Interferon alpha consolidation after intensive chemotherapy does not prolong the progression-free survival of patients with low-grade non-Hodgkin's lymphoma: results of the Southwest Oncology Group randomized phase III study 8809.

PURPOSE: S8809 is a randomized phase III trial determining whether intensive cytoreductive treatment, followed by interferon consolidation at the time of minimal residual disease, prolongs the progression-free survival (PFS) or overall survival (OS) of indolent lymphoma patients. PATIENTS AND METHODS: Five hundred seventy-one patients with previously untreated stage III or IV low-grade non-Hodgkin's lymphoma were registered. Patients received six to eight cycles of prednisone, methotrexate, doxorubicin, cyclophosphamide, and etoposide/mechlorethamine, vincristine, procarbazine, and prednisone (ProMACE[day 1]-MOPP[day 8]) chemotherapy or chemotherapy plus radiotherapy. Responding patients were randomized to observation alone or to interferon consolidation. Interferon alpha-2b 2 mU/m(2) was given subcutaneously three times weekly for 2 years. RESULTS: Two hundred sixty-eight eligible patients were randomized to interferon alpha consolidation (n = 144) or observation alone (n = 124). With a median follow-up time from randomization among patients still alive of 6.2 years, the median PFS time was 4.1 years for patients who received interferon consolidation therapy and 3.2 years for patients who were observed after ProMACE-MOPP induction (P =.25). The adjusted hazard ratio for relapse for observation to interferon was 0.83 (95% confidence interval [CI], 0.61 to 1.13). The median OS has not been reached in either group. At 5 years, OS is 78% for the interferon group and 77% for the observation group (P =.65). The adjusted hazard ratio for survival for observation to interferon is 1.11 (95% CI, 0.69 to 1. 79). CONCLUSION: Interferon alpha consolidation therapy after intensive treatment with anthracycline-containing combination chemotherapy and involved-field radiation therapy does not prolong the PFS or OS of patients with low-grade non-Hodgkin's lymphoma.

Adult↗

PubMed2000

The use of video-based patient education for shared decision-making in the treatment of prostate cancer.

Increased consumerism, patient empowerment, and autonomy are creating a health care revolution. In recent years, the public has become better informed and more sophisticated. An extraordinary amount of treatment advice from books, the media, and the Internet is available to patients today, although much of it is confusing or conflicting. Consequently, the traditional, paternalistic doctor-patient relationship is yielding to a more consumerist one. The new dynamic is based on a participatory ethic and a change in the balance of power. This shared decision-making creates a true partnership between professionals and patients, in which each contributes equally to decisions about treatment or care. Evidence suggests that in diseases such as prostate cancer, where there may be a number of appropriate treatment options for a particular patient, shared decision-making may lead to improved clinical and quality-of-life outcomes. This article explores the evolving relationship between the physician and patient, the pros and cons of shared decision-making, and the use of video technology in the clinical setting. The authors review the use of medical decision aids, including a video-based educational program called CHOICES, in the treatment of prostate cancer and other diseases.

Decision Making↗

PubMed2000