PubMed Health⌕ Search

Biomedical subjects

B R Prestidge

Publications and source records attributed to B R Prestidge.

30 records · Page 2Linked to original sources
PubMed1997

Posttreatment biopsy results following interstitial brachytherapy in early-stage prostate cancer.

PURPOSE: To assess pathologic control rates for prostatic carcinoma as determined by postimplant prostate biopsy in a large series of consecutive patients who have received permanent interstitial brachytherapy using a contemporary transrectal ultrasound-directed, transperineal, computer generated, volume technique. METHODS AND MATERIALS: Four hundred and two patients received permanent 125I or 103Pd interstitial brachytherapy as primary treatment for early stage prostatic carcinoma at the Northwest Tumor Institute between January 1988 and January 1994. Of these, 201 have consented to biopsy 12 or more months postimplant with a median follow-up of 40 months (range: 12-83 months). None had received hormonal manipulation. A total of 361 biopsies was performed on 201 patients with a range of one to six annual biopsies per patient (91 received multiple, serial biopsies). Of the 161 patients more than 12 months postimplant who have not been biopsied, most have been unwilling or unable to submit to biopsy. Only six patients with biochemical progression have not been biopsied. There was no difference in the presenting characteristics or implant parameters between those patients biopsied and those that were not. One hundred and forty-three received 125I (71%) prescribed to a MPD of 160 Gy with a median activity of 35.5 mCi, and 58 (29%) received 103Pd prescribed to a MPD of 115 Gy with a median activity of 123 mCi. Multiple biopsies were performed under transrectal ultrasound guidance, and all specimens were classified as either negative, indeterminate, or positive. RESULTS: At the time of last biopsy, 161 (80%) have achieved negative pathology, 34 (17%) remain indeterminate, and 6 (3%) have been positive. Only 2 of the 186 patients with a PSA < 4.0 ng/ml at the time of biopsy were positive. Among those 33 indeterminate patients with a subsequent biopsy, 28 have converted to negative, 2 to positive, and 3 remain unchanged to date. CONCLUSIONS: These data demonstrate at least an 80% pathologically confirmed local control rate following permanent interstitial brachytherapy for early stage prostate cancer. A higher local control rate is expected with further follow-up as the majority of indeterminate biopsies convert to negative over time. The indeterminate category of postirradiation biopsy described here includes specimens that have probably been interpreted as positive in other series, but correlate clinically and biochemically with negative biopsies. These results support the use of modern interstitial brachytherapy techniques for selected patients with early stage adenocarcinoma of the prostate.

Biopsy↗
PubMed1997

The coupling of anisotropy and radial dose functions for 103Pd and 125I for use with a commercial treatment planning system.

Many commercial treatment planning systems available today employ traditional dose calculation formulae in their interstitial brachytherapy source calculation algorithms. The 1995 AAPM report on interstitial brachytherapy source dosimetry recommended a new dose calculational formalism and presented a technique for adopting it on systems which embody traditional formalism. In order to comply with these recommendations on our system, the transformations for implementing a one dimensional isotropic point source model were modified by coupling the published anisotropy and radial dose corrections and fitting them to a fifth order polynomial. Using this approach, a more accurate dose calculation is obtained.

Algorithms↗
PubMed1994

Predictors of survival after a positive post-irradiation prostate biopsy.

PURPOSE: Considerable debate persists in the urologic oncology literature with regard to the optimum management of patients with a positive post-irradiation prostate biopsy. This analysis characterizes a group of such patients who have had a favorable course without intervention. METHODS AND MATERIALS: Between 1956 and 1991, 116 patients have had a positive prostate biopsy 12 or more months post-irradiation without hormonal intervention or evidence of distant relapse. The population had an age range of 42 to 82 years (median - 61). American Joint Committee on Cancer stages included 1 T1, 70 T2, 44 T3, and 1 T4. Median actuarial survival for the entire population was 14.4 years (range = 2.2-21.5 years) from presentation and 5.2 years from re-biopsy. RESULTS: Fifty-one of the 116 patients developed metastases subsequent to re-biopsy and 65 remain free from distant relapse. Among these 65 patients, 50 remain alive and otherwise well, 11 have died of other causes, and only four have succumbed to their local disease. The best predictor of distant relapse subsequent to re-biopsy was digital rectal exam. Forty-one of the 51 patients later developing metastases had an abnormal digital rectal exam compared to 37 of 65 with sustained distant control (p = .01). CONCLUSION: These data demonstrate that long-term, disease-free (other than re-biopsy) survival is common following a "positive" post-irradiation biopsy without intervention especially among patients with a normal digital rectal exam. Therefore, routine re-biopsy without clinical indications is not a useful practice.

Adenocarcinoma↗
PubMed1994

Ultrasound guided placement of transperineal prostatic afterloading catheters.

PURPOSE: A new method of performing temporary prostate brachytherapy which does not require an open laparotomy is described. METHODS AND MATERIALS: This procedure allows dynamic visualization of the placement of 13-gauge (I-125) or 17-gauge (Ir-192) afterloading catheters into the prostate gland via saggital ultrasound imaging. The image enables visualization of the entire path of the catheter as well as cephalad gland movement. The prostate gland, seminal vesicles, bladder neck, urethra, and rectum are easily identified and implanted, if desired, during the procedure. This procedure has been used in 34 patients as an interstitial boost for locally advanced (T2b, T3) prostatic carcinoma following external beam therapy as a means to safely deliver higher doses to the gland. Another eight patients have undergone this procedure as salvage following failure of prior radical prostatectomy or external beam therapy. RESULTS: Very customized dosimetry has been obtained using this technique as a result of the optimal catheter placement achieved under ultrasound guidance, particularly with I-125. Although it is too early to evaluate efficacy, the procedure has been well tolerated and is associated with minimal morbidity to date. CONCLUSION: This new procedure seems to be an excellent means of safe delivery of higher doses to the gland compared to conventional external beam therapy. Due to the ability to cover the seminal vesicles as well as the afterloading nature of this procedure, a more customized implant is obtained relative to most permanent techniques, and open laparotomy is not required.

Brachytherapy↗
PubMed1992

The clinical significance of a positive post-irradiation prostatic biopsy without metastases.

To define the prognostic value of a post-irradiation prostatic biopsy, the outcome of 203 previously irradiated patients who underwent post-treatment biopsy was analyzed. The majority of patients were selected for biopsy based on an abnormal digital rectal exam or elevated prostate specific antigen. Patients with distant metastases found at the time of biopsy were excluded from further analysis. One hundred thirty-nine (139) of these had a positive biopsy and 64 were negative. Those with a positive biopsy tended to present with more locally-advanced (Stage B2/C) tumors (61%) compared to those with negative biopsies (42%). The 10- and 15-year survival and cause-specific survival from the time of initial presentation were similar for both groups. However, those with a negative biopsy had a more favorable survival and cause-specific survival from the time of post-treatment biopsy and were less likely to develop distant metastases than the positive biopsy group. These data suggest that a positive prostatic biopsy is associated with a greater likelihood of subsequent distant relapse and decreased survival following biopsy relative to patients with negative biopsies. Since a positive post-treatment biopsy is more likely among patients presenting with locally-advanced disease, perhaps more aggressive initial therapy (i.e., interstitial boost or hyperthermia) would benefit this subgroup.

Adenocarcinoma↗
PubMed1992

The importance of local control in the treatment of prostatic cancer.

In a retrospective analysis of 946 patients with prostatic carcinoma treated with external beam radiotherapy between 1958 and 1989 at Stanford University Hospital the 15-year actuarial clinical local control rate was 77.8 +/- 3.3% for Stanford stage T1, 61.3 +/- 4.4% for stage T2 and 64.9 +/- 4.8% for stage T3 disease. Overall, there was improvement in disease-specific survival without a significant alteration in survival in patients who achieved clinical local control. For the 50 Stanford stage T1 cases with local control on clinical examination and a positive post-treatment biopsy a decrease in disease-specific survival was observed. There was no difference in disease-specific survival for comparable stage T2 or T3 cases. In an analysis of patients who underwent ultrasound guided prostatic biopsy performed after irradiation the trend of prostate specific antigen was more important than biopsy results in predicting which patients would have relapse.

Follow-Up Studies↗
PubMed1991

Non-small cell lung cancer: treatment results at a USAF referral center.

The treatment results of 197 consecutive patients with non-small cell carcinoma of the lung managed at David Grant USAF Medical Center between January 1978 and September 1985 were reviewed. Patients were staged according to 1983 AJCC criteria as follows: 52 stage I, 28 stage II, and 117 stage III. Five-year survival and freedom from relapse (FFR) were 24% and 32%, respectively, for the entire population. Survival and FFR by stage were: stage I, 68% and 77% (5-year); stage II, 32% and 43% (5-year); and stage III, 10% and 10% (3-year), respectively.

Adult↗
PubMed1990

Prostate specific antigen after irradiation for prostatic carcinoma.

The clinical significance of serum prostate specific antigen after primary irradiation for adenocarcinoma of the prostate is uncertain. Between September 1986 and December 1987 serial prostate specific antigen values were determined in 43 patients before and after definitive radiation therapy. The study group included 6 patients with stage T0d, 10 with stage T1, 11 with stage T2 and 16 with stage T3 disease, with a mean pre-treatment prostate specific antigen level of 49.2 +/- 10.8. For all patients the first post-treatment prostate specific antigen level was less than the pre-treatment level. One patient failed locally with recurrent prostatic cancer that invaded the rectum. The 6 patients who failed with symptomatic metastases had an increasing prostate specific antigen level 2 to 7 months before detection of recurrence. Based on the absolute value and trend of the prostate specific antigen, patients were described as being at high, intermediate or low risk for distant metastases. Of 9 high, 6 intermediate and 28 low risk patients 4 (44%), 2 (33%) and 0 (0%) have experienced recurrent disease (p = 0.0025). We conclude that serial post-irradiation prostate specific antigen values may be useful in the early identification of patients at risk for treatment failure.

Adenocarcinoma↗
PubMed1989

Treatment results among adults with childhood tumors: a 20-year experience.

Controversy exists regarding the most appropriate treatment for the rare adult patient who develops a so-called pediatric cancer. We have reviewed our 20-year experience with these patients and analyzed their outcome. A total of 299 patients with rhabdomyosarcoma (106), Wilms' tumor (97), and neuroblastoma (96) were evaluated and treated at Stanford University Medical Center between January 1967 and December 1987. Only 26 of these patients (8.7%) were diagnosed during "adulthood"; their age range was 18-67 years, median 23 years. Wilms' tumor; Five patients presented with Wilms' tumor at age greater than or equal to 18 years; four had unfavorable histology. All underwent multimodality therapy; however, only two have survived, one currently disease-free and one with disease. Neuroblastoma: Five patients presented with neuroblastoma at age greater than or equal to 18 years. Four underwent attempted surgical resection, post-operative irradiation (RT), and chemotherapy (CT); the other received no adjuvant CT. Only two of the five patients survive, both with disease. Rhabdomyosarcoma: Of the 16 adults (greater than or equal to 21 years) with rhabdomyosarcoma, 14 (87%) had advanced Intergroup Rhabdomyosarcoma Study-group disease (eight Group III, six Group IV). All 16 underwent aggressive multimodality therapy. At 10 months-16 years follow-up, only five patients survive, four of whom are apparently cured of their tumor. Neither histologic subtype nor site of presentation were of prognostic value. This series demonstrates that adults with Wilms' tumor, neuroblastoma, or rhabdomyosarcoma have a worse prognosis than do children with the same diagnosis. Possible explanations for this disparity in outcome include different tumor biology, less tolerance for treatment, and different natural history among adults relative to children.

Adolescent↗
PubMed1988

Combined modality therapy for stage I-II large cell lymphoma.

Between January 1978 and December 1986, 94 patients with Stage I-II large cell lymphoma were evaluated at Stanford University Medical Center and treated with a combination of chemotherapy (CTX) and irradiation (XRT). The predominant histology was diffuse large cell (78), followed by immunoblastic (7), follicular large cell (6), and diffuse mixed small and large cell lymphoma (3). Twenty-three patients had Stage I and 71 had Stage II disease. Fifty-one had extranodal involvement (13 IE, 38 IIE), and 11 had B symptoms (2 IB, 9 IIB). Lymphoma was supradiaphragmatic in 58 patients, infradiaphragmatic in 21, and only in extranodal sites in 15. Patients received either involved (81) or extended (13) field XRT with a median dose of 40 Gy and combination CTX with 2 to 9 cycles (median 6) of either CHOP (68), M-BACOD (8), C-MOPP (8), MACOP-B (4), or other (6). Seventy-two patients remain with no evidence of disease, 21 are dead with disease, and one suffered an intercurrent death. Among the 19 patients who relapsed, there were six failures within the XRT field only, two within and outside the XRT field, and 11 outside of the XRT fields only. Actuarial survival and freedom from relapse (FFR) for the entire population were 74% and 72% at 5-years, respectively (33 month median follow-up). Stage I patients achieved 81% survival and 78% FFR, and Stage II patients had 72% survival and 70% FFR. In univariate and multivariate analyses, a favorable outcome was associated with the CTX-XRT-CTX sequence of therapy (p = 0.001), low LDH (p = 0.01), and small tumor bulk (p = 0.04). There were no relapses or deaths among the 21 patients receiving the "sandwich" sequence (CTX-XRT-CTX) of therapy. This series may serve as a comparison with single modality treatment programs for localized large cell lymphoma using either XRT or CTX alone.

Actuarial Analysis↗
PubMed1987

Prevalence and recognition of depression among primary care outpatients.

Studies indicate that more individuals suffering from depressive symptoms will present to the primary care outpatient clinic than to any other medical care setting. Unfortunately, most of these patients complain of somatic problems, not mood disturbances. Consequently, less than one half of all depressed patients in the primary care clinic are initially identified and treated for their depression. As depression causes considerable morbidity and some mortality and is treatable, methods of improving recognition should be sought. Some of these include maintaining a high index of suspicion, conducting a brief but thorough screening interview for depression, and using a depression rating scale. Benefits derived from early recognition include saving time, effort, and money spent on unnecessary tests and inappropriate treatment, and avoiding substantial suffering. The threshold for many somatic complaints can be substantially raised with resolution of depression.

Depression↗