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Biomedical subjects

Raphael Pfeffer

Publications and source records attributed to Raphael Pfeffer.

8 recordsLinked to original sources
PubMed2006

Cardiovascular calcifications after radiation therapy for Hodgkin lymphoma: computed tomography detection and clinical correlation.

OBJECTIVE: To study cardiovascular calcifications, detected by computed tomography, in patients following mediastinal radiation for Hodgkin lymphoma, and correlate them with clinical findings. MATERIALS AND METHODS: Fifteen patients, <or=55 years, with computed tomography detected cardiovascular calcifications after mediastinal radiotherapy for Hodgkin lymphoma were identified during a 10-year period. Calcifications were evaluated for site and extent and were correlated with clinical data including symptoms and signs of heart disease, angiographic and surgical findings. RESULTS: Accelerated calcifications were detected in the coronary arteries (n=11), in the aorta (n=11), and in the aortic valve and the mitral apparatus (n=8). Calcifications were more extensive when radiation was given at a young age. Clinical evidence of cardiovascular disease included coronary events in three patients, valvular dysfunction in two, pericarditis in two and complete atrioventricular block in one. Seven patients had no cardiac symptoms. CONCLUSION: Early cardiovascular calcifications can be radiation associated. Such calcifications may represent radiation-induced atherosclerosis and can be detected by computed tomography even in asymptomatic patients. The implication of our findings is that spiral computed tomography may serve as a non-invasive modality to detect accelerated cardiovascular calcifications in high-risk asymptomatic patients who survived Hodgkin lymphoma.

Adult↗
PubMed2004

Does rectal wall tumor eradication with preoperative chemoradiation permit a change in the operative strategy?

PURPOSE: Preoperative chemoradiation may downstage locally advanced rectal cancer and, in some cases, with no residual tumor. The management of complete response is controversial and recent data suggest that radical surgery may be avoided in selected cases. Transanal excision of the scar may determine the rectal wall response to chemoradiation. This study was designed to assess whether the absence of tumor in the bowel wall corresponds to the absence of tumor in the mesorectum, known as true complete response. METHODS: A retrospective review of the medical records of patients who underwent preoperative chemoradiation for advanced mid (6-11 cm from the anal verge) and low (from the dentate line to 5 cm from the anal verge) rectal cancer (uT2-uT3) followed by radical surgery with total mesorectal excision was undertaken. Patients in whom the pathology specimen showed no residual tumor in the rectal wall (yT0, "y" signifies pathologic staging in postradiation patients) were assessed for tumoral involvement of the mesorectum. RESULTS: A total of 109 patients underwent preoperative, high-dose radiation therapy (94 percent with 5-fluorouracil chemosensitization), followed by radical surgery for advanced rectal cancer. Preoperatively, 47 patients were clinically assessed to have potentially complete response. After radical rectal resection, pathology did not reveal any residual tumor within the rectal wall (yT0) in 17 patients. In two (12 percent) of these patients, the mesorectum was found to be positive for malignancy: one had positive lymph nodes that harbored cancer; one had tumor deposits in the mesorectal tissue. CONCLUSIONS: Compete rectal wall tumor eradication does not necessarily imply complete response, because the mesorectum may harbor tumor cells. Thus, caution should be exercised when considering the avoidance of radical surgery. Reliable imaging methods and clinical predictors for favorable outcome are important to allow less radical approaches in the future.

Adenocarcinoma↗
PubMed2004

Convection-enhanced delivery of paclitaxel for the treatment of recurrent malignant glioma: a phase I/II clinical study.

OBJECT: A minority of patients with recurrent glioblastomas multiforme (GBMs) responds to systemic chemotherapy. The authors investigated the safety and efficacy of intratumoral convection-enhanced delivery (CED) of paclitaxel in patients harboring histologically confirmed recurrent GBMs and anaplastic astrocytomas. METHODS: Fifteen patients received a total of 20 cycles of intratumoral CED of paclitaxel. The patients were observed daily by performing diffusion-weighted (DW) magnetic resonance (MR) imaging to assess the convective process and routine diagnostic MR imaging to identify the tumor response. Effective convection was determined by the progression of the hyperintense signal within the tumor on DW MR images, which corresponded to a subsequent lytic tumor response displayed on conventional MR images. Of the 15 patients, five complete responses and six partial responses were observed, giving a response rate of 73%. The antitumor effect was confirmed by one biopsy and three en bloc resections of tumors, which showed a complete response, and by one tumor resection, which demonstrated a partial response. Lack of convection and a poor tumor response was associated with leakage of the convected drug into the subarachnoid space, ventricles, and cavities formed by previous resections, and was seen in tumors containing widespread necrosis. Complications included transient chemical meningitis in six patients, infectious complications in three patients, and transient neurological deterioration in four patients (presumably due to increased peritumoral edema). CONCLUSIONS: On the basis of our data we suggest that CED of paclitaxel in patients with recurrent malignant gliomas is associated with a high antitumor response rate, although it is associated with a significant incidence of treatment-associated complications. Diffusion-weighted MR images may be used to predict a response by demonstrating the extent of convection during treatment. Optimization of this therapeutic approach to enhance its efficacy and reduce its toxicity should be explored further.

Adult↗
PubMed2004

Salvage prostatic fossa radiation therapy for biochemical failure after radical prostatectomy: the Sheba experience.

BACKGROUND: The role of prostatic fossa radiation as salvage therapy in the setting of a rising prostate-specific antigen following radical prostatectomy is not well defined. OBJECTIVES: To study the efficacy and safety of pelvic and prostatic fossa radiation therapy following radical prostatectomy for adenocarcinoma. METHODS: A retrospective review of the charts of 1,050 patients treated at the Sheba Medical Center for prostate cancer between 1990 and 2002 identified 48 patients who received post-prostatectomy pelvic and prostatic fossa radiotherapy for biochemical failure. Two patients were classified as T1, T2A-9, T2B-19, T3A-7 and T3B-11. Gleason score was 2-4 in 9 patients, 5-6 in 22 patients, 7 in 10 patients and 8-10 in 7 patients. Positive surgical margins were noted in 28 patients (58%) of whom 18 had single and 10 had multiple positive margins. Radiation was delivered with 6 mV photons using a four-field box to the pelvis followed by two lateral arcs to the prostatic fossa. RESULTS: At a median follow-up of 34.3 months (25th, 75th) (14.7, 51.3) since radiation therapy, 32 patients (66%) are free of disease or biochemical failure. Exploratory analysis revealed that a pre-radiation PSA less than 2 ng/ml was associated with a failure rate of 24% compared with 66% in patients with a pre-radiation PSA greater than 2 ng/ml (chi-square P < 0.006). CONCLUSIONS: For patients with biochemical failure following radical prostatectomy early salvage radiation therapy is an effective and safe treatment option.

Humans↗
PubMed2003

Early detection of response to radiation therapy in patients with brain malignancies using conventional and high b-value diffusion-weighted magnetic resonance imaging.

PURPOSE: To study the feasibility of using diffusion-weighted magnetic resonance imaging (DWMRI), which is sensitive to the diffusion of water molecules in tissues, for detection of early tumor response to radiation therapy; and to evaluate the additional information obtained from high DWMRI, which is more sensitive to low-mobility water molecules (such as intracellular or bound water), in increasing the sensitivity to response. PATIENTS AND METHODS: Standard MRI and DWMRI were acquired before and at regular intervals after initiating radiation therapy for 10 malignant brain lesions in eight patients. RESULTS: One week posttherapy, three of six responding lesions showed an increase in the conventional DWMRI parameters. Another three responding lesions showed no change. Four nonresponding lesions showed a decrease or no change. The early change in the diffusion parameters was enhanced by using high DWMRI. When high DWMRI was used, all responding lesions showed increase in the diffusion parameter and all nonresponding lesions showed no change or decrease. Response was determined by standard MRI 7 weeks posttherapy. The changes in the diffusion parameters measured 1 week after initiating treatment were correlated with later tumor response or no response (P <.006). This correlation was increased to P <.0006 when high DWMRI was used. CONCLUSION: The significant correlation between changes in diffusion parameters 1 week after initiating treatment and later tumor response or no response suggests the feasibility of using DWMRI for early, noninvasive prediction of tumor response. The ability to predict response may enable early termination of treatment in nonresponding patients, prevent additional toxicity, and allow for early changes in treatment.

Brain↗
PubMedDate not supplied

Pretreatment prediction of brain tumors' response to radiation therapy using high b-value diffusion-weighted MRI.

Diffusion-weighted magnetic resonance imaging (DWMRI) is sensitive to tissues' biophysical characteristics, including apparent diffusion coefficients (ADCs) and volume fractions of water in different populations. In this work, we evaluate the clinical efficacy of DWMRI and high diffusion-weighted magnetic resonance imaging (HDWMRI), acquired up to b = 4000 sec/mm(2) to amplify sensitivity to water diffusion properties, in pretreatment prediction of brain tumors' response to radiotherapy. Twelve patients with 20 brain lesions were studied. Six ring-enhancing lesions were excluded due to their distinct diffusion characteristics. Conventional and DWMRI were acquired on a 0.5-T MRI. Response to therapy was determined from relative changes in tumor volumes calculated from contrast-enhanced T1-weighted MRI, acquired before and a mean of 46 days after beginning therapy. ADCs and a diffusion index, R(D), reflecting tissue viability based on water diffusion were calculated from DWMRIs. Pretreatment values of ADC and R(D) were found to correlate significantly with later tumor response/nonresponse (r = 0.76, P <.002 and r = 0.77, P <.001). This correlation implies that tumors with low pretreatment diffusion values, indicating high viability, will respond better to radiotherapy than tumors with high diffusion values, indicating necrosis. These results demonstrate the feasibility of using DWMRI for pretreatment prediction of response to therapy in patients with brain tumors undergoing radiotherapy.

Brain↗