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Biomedical subjects

P P Kumar

Publications and source records attributed to P P Kumar.

At least 19 recordsLinked to original sources
PubMed1993

Continuous low dose rate brachytherapy with high activity iodine-125 seeds in the management of meningiomas.

The purpose of this study was to evaluate if meningiomas can be effectively treated with brachytherapy using permanent implantation of high activity I-125 seeds. Thirteen patients with intracranial meningiomas were treated by means of permanent stereotactic implantation of one or more high-activity I-125 seeds. The physical characteristics of I-125 enabled us to deliver a minimum tumor dose ranging from 100 Gy to 500 Gy at a low dose rate of 5 cGy to 25 cGy per hr. Indications for this procedure included recurrence after initial surgery or as primary modality of treatment in patients who were not candidates for surgery. All 13 patients are alive at a median follow-up of 25 months. Nine of 13 patients achieved complete resolution of the tumor and in the remaining four, more than 50% reduction in tumor volume was noted at the last follow-up. No late complications were observed. We conclude from this initial data that localized high dose irradiation delivered at a low dose rate using I-125 permanent implantation is an effective, safe, and simple method in the treatment of both recurrent and primary intracranial meningiomas.

Adult↗
PubMed1993

Intracranial skip metastasis from parotid and facial skin tumors: mechanism, diagnosis, and treatment.

Perineural and endoneural tumor spread is a form of metastatic disease in which the primary tumors spread along neural pathways and gain access to noncontiguous regions. Although rare, this type of skip metastasis into the cranial cavity occurs from tumors of the parotid gland and facial skin. Recognition of this process, evaluation of the patient with proper diagnostic procedures, and its treatment are presented.

Brachytherapy↗
PubMed1992

Estimation of the mean effective organ doses for total body irradiation from Rando phantom measurements.

For the total body irradiation (TBI) procedure, it is necessary to compare the mean dose obtained from the tissue or organs and the estimated dose equivalent value from the computer program. Due to the easy-access of the Rando phantom and repeatability of TLDs and its output, the results from the experiment are quite encouraging for the verification of the dose distributions from total body irradiation at the given prescribed monitor units. The estimation of effective dose equivalent particularly across the lung sections was studied by combinations of using arms as the scatter volume to compensate for the inhomogeneity across the breast portion, as well as using the spoiler for skin-sparing purposes. The results were based upon various beam quality such as 4 MV, 6 MV, and 10 MV X rays. One series of experiments performed for this survey to ascertain the dose equivalent of the tissues was conducted. This paper describes the method and procedure for comparison between the measured data and computed data as a reference in the dosimetry of total body irradiation. Comparison of the measured and computed data for the largest collimated field shows that the calculated dose rates do not differ by more than 2% from the measured data. Because uncertainty is inherent in non-patient-like phantoms, the calculated data may be served as a reference for the dosimetry. For the total body irradiation setup, considering the radiation field size and treatment distances commonly employed, we conclude that the best combination of the patient setup will be (1) laying both arms down as compensation for lung inhomogeneity, and (2) the spoiler, which is made of acrylic about 8 mm thick and functions like a bolus, is needed to reduce the skin sparing effects and contribute the uniform dose distribution. The beam spoiler with the frame stands near the patient during the treatment.

Humans↗
PubMed1992

Stereotactic external beam irradiation system.

Stereotactic localization is of vital importance in treating small intracranial lesions either with interstitial or external beam irradiation. This article describes a simple, fast, accurate, and verifiable system that can be used with a standard computerized axial tomography (CAT) scanner and linear accelerator for stereotactic external beam irradiation.

Brachytherapy↗
PubMed1991

The residual mediastinal mass following radiation therapy for Hodgkin's disease.

Thirty-two patients with mediastinal involvement by Hodgkin's disease (HD), treated with an isocentric technique of extended-field radiation therapy (RT) with or without chemotherapy, are described. Twenty-nine patients (91%) had a complete response to therapy and four patients subsequently relapsed, with a median follow-up of 54 months. Five of seven patients not in continuous complete remission were salvaged, with one additional salvage therapy. Ten patients had persistent mediastinal masses at 1 year, following completion of planned therapy; only one of these has had recurrent disease. Of those who achieved complete response, only one patient has had disease recurrence in the mediastinum. We conclude that extended-field RT, using an isocentric technique, provides excellent local disease control in HD; however, persistent mediastinal widening after therapy is frequent, and additional therapy should not be given in the absence of conclusive evidence of disease progression.

Adolescent↗
PubMed1991

Improved results of allogeneic bone marrow transplantation for advanced hematologic malignancy using busulfan, cyclophosphamide and etoposide as cytoreductive and immunosuppressive therapy.

Twenty-four patients between the ages of 8 and 48 years (median 27.5) with high-risk for relapse hematologic malignancy received a marrow transplant from an HLA and MLC compatible sibling donor after chemotherapy with busulfan, 4 mg/kg/day for 4 days by mouth, cyclophosphamide 60 mg/kg/day i.v. for 2 days, and etoposide 60 mg/kg i.v. over 4 h on the first day of cyclophosphamide treatment (BU/CY/VP). Toxicity consisted of mucositis, skin rash, and nausea and vomiting in all patients, transient fever thought to be due to etoposide administration in 16/24 (67%) patients, and clinical veno-occlusive disease (VOD) of the liver in 4/24 (17%). There were nine deaths from causes other than recurrent disease in the first 100 days after transplant and two deaths after day 100, a total transplant mortality of 11/24 (46%). Three patients relapsed, but 10/24 (40%) remain alive and disease free 26-182 weeks (median 60 weeks) from transplant. These results compare favorably with results in a group of 12 similar risk patients treated with total body irradiation (TBI) containing regimens during an overlapping time period. Six of the TBI patients have had persistent or recurrent disease and only two (17%) are currently alive and disease free. The probability of disease persistence or relapse is 67% in the TBI group and 20% in the BU/CY/VP group (p less than 0.02).

Adolescent↗
PubMed1991

Brachytherapy: a viable alternative in the management of basal meningiomas.

Thirteen patients with intracranial meningiomas of the skull base were treated with one or more high-activity iodine-125 seeds. In 11 patients, the seeds were implanted stereotactically under local anesthesia. A minimum dose of 100 to 500 Gy was delivered to the tumor at a dose rate of 5 to 25 cGy/h. Indications for this procedure included recurrence after initial surgery or as the primary modality of treatment in patients who were not candidates for surgery. All 13 patients are alive at a median follow-up of 15 months. Nine of 11 patients (82%) without calcification in their meningiomas achieved complete response. The remaining 4 patients-2 with calcification and 2 without--achieved partial response. No early or late complications were observed. We conclude from our experience that both recurrent and primary meningiomas of the skull base can be treated effectively with permanent iodine-125 brachytherapy.

Adult↗
PubMed1990

Applicator for use of cesium-137 miniaturized tube sources in the treatment of uterine cervix cancer.

A modified afterloading Kumar Cervical Applicator with a 3 mm diameter central tandem permits insertion of the afterloading tandem into the uterus without need of manual cervical dilatation. While general anesthesia is required for insertion of standard cervical applicators, this is eliminated because the central tandem is no larger than a uterine sound, and the tandem may be painlessly inserted into the uterus while the patient is awake.

Brachytherapy↗
PubMed1990

Radiation therapy alone versus radiation therapy and chemotherapy in the management of Hodgkin's disease.

Forty-four patients with histologically proven Hodgkin's disease underwent initial treatment with extended-field radiation therapy. Nineteen of these patients also received combination chemotherapy. For analysis, patients were assigned to three treatment groups: group 1 received radiation therapy only (25 patients); group 2 received combination chemotherapy followed by consolidative (low-dose extended-field) radiation therapy; and group 3 was treated with alternate chemotherapy and radiation therapy using the sandwich technique. The actuarial 5-year disease-free survival rates were 83% (group 1), 83% (group 2), and 100% (group 3). The overall actuarial survival rates were 96% (group 1), 92% (group 2), and 100% (group 3). No factor was identified as being of prognostic value in predicting relapse. We conclude that extended-field radiation therapy delivered in this manner is a safe and effective approach to the initial management of Hodgkin's disease.

Adolescent↗
PubMed1990

Iodine 125 interstitial irradiation for localized prostate cancer.

We present the technique, complications, and 5-year results of transperineal percutaneous template permanent interstitial iodine 125 endocurietherapy of localized prostate cancer in 85 treated patients. The 5-year outcome appears similar to that of external beam radiation therapy or radical surgery, but the iatrogenic mortality, morbidity, treatment time, and hospitalization are significantly reduced.

Ambulatory Care↗
PubMed1989

Survival of patients with glioblastoma multiforme treated by intraoperative high-activity cobalt 60 endocurietherapy.

The authors report their initial treatment results in 49 patients with glioblastoma multiforme (GM) who received intraoperative endocurietherapy (ECT) with high-activity cobalt 60 (60Co) probe. Thirty poor prognosis (unresectable tumor) patients (Group I) with newly diagnosed GM were treated by either biopsy or subtotal excision, followed by 20.00-Gy single-fraction 60Co probe ECT, and 60.00-Gy external-beam radiation therapy (EXRT) (80.00 Gy total tumor dose). Nineteen patients (Group II) with recurrent, previously resected and externally irradiated GM were retreated with 20.00-Gy single-fraction 60Co probe ECT alone. The authors' initial experience with intraoperative ECT of GM is discussed.

Adolescent↗
PubMed1989

High-activity iodine-125 endocurietherapy for head and neck tumors.

Inoperable solid tumor recurrence within a surgical bed or within a previously irradiated field usually responds poorly to re-treatment with conventional external beam irradiation (EXRT) and/or chemotherapy. We present a new, alternative method of re-treatment used in two patients with recurrent head and neck cancer involving the parotid (adenocarcinoma) and neck nodes (squamous cell carcinoma). These patients were successfully re-treated with high-activity 125iodine (I-125) permanent implantation.

Adenocarcinoma↗
PubMed1989

Need for invasive diagnostic procedures in the management of superior vena cava syndrome.

Radiation therapy is considered the first treatment of choice for thoracic malignant diseases causing superior vena cava syndrome (SVCS). However, its use is poorly documented in cases in which intravascular tumor thrombosis is the major cause of obstructive symptoms. We report two cases of SVCS caused by thoracic malignancy. The first case failed to respond to the initial course of mediastinal radiation therapy. Contrast and radionuclide venography revealed two sites of tumor thrombosis located outside the radiation portal. Irradiation of these areas resulted in prompt relief of symptoms and complete relief of obstruction. In the second case, superior venacavogram and transluminal biopsy established the diagnosis and location of superior vena cava obstruction.

Aged↗
PubMed1988

Contrast-enhancing computed tomography ring in glioblastoma multiforme after intraoperative endocurietherapy.

The significance of the contrast-enhancing ring seen on serial follow-up postirradiation computed tomograms (CT) of the brain was evaluated in a group of 41 patients with glioblastoma multiforme (GM) who were treated in a phase I/II study by means of intraoperative remote afterloading endocurietherapy (ECT) with a high activity cobalt 60 probe (20.00 Gy) in one high-dose rate fraction), and conventional fractionated external-beam (EXRT) radiotherapy (60.00 Gy in 30 fractions in 7.5 weeks). All received minimum total tumor doses of 80.00 Gy. After completion of treatment, all patients were followed with serial CT scans of the brain. Two to 6 months after treatment, 27 of 41 patients developed the similar thin-walled, regular, contrast-enhancing CT rings with low-density attenuation inside and outside the ring. Postmortem study in two of these patients revealed that the thin-walled, regular, contrast-enhancing ring represented a continuous capsule of dilated cerebral vessels with inner low-density attenuation corresponding to necrosis, and outer low-density attenuation corresponding to edema. The CT appearance of the thin-walled, regular, contrast-enhancing ring produced after high-dose rate intraoperative ECT and EXRT is distinctly different from the CT ring characteristic of untreated or recurrent GM. After high-dose rate intracranial ECT and EXRT, the appearance of a post-ECT contrast-enhancing CT ring should not be automatically interpreted as recurrent disease as previously reported after conventional fractionated EXRT.

Blood Vessels↗
PubMed1988

High activity iodine 125 endocurietherapy for recurrent skull base tumors.

Experience with endocurietherapy of skull base tumors is reviewed. We present our cases of recurrent pituitary hemangiopericytoma, radiation-induced recurrent meningioma, recurrent clival chordoma, recurrent nasopharyngeal cancer involving the cavernous sinus, and recurrent parotid carcinoma of the skull base which were all successfully retreated with high-activity 125iodine (I-125) permanent implantation.

Adenocarcinoma↗
PubMed1988

Transperineal 125iodine endocurietherapy of prostate cancer.

We present the improved implant technique, intraoperative and postoperative complications, local control, and survival of 67 patients with cancer of the prostate treated by means of percutaneous transperineal template permanent 125iodine interstitial endocurietherapy (ECT). This ECT technique is a simple, easily learned, accurate and rapid procedure that can be performed without subjecting the patient to celiotomy. The use of vicryl carriers for permanent 125iodine implantation of the prostate with the percutaneous transperineal template technique prevents seed loss and permits implantation of patients after transurethral resection of the prostate (TURP).

Brachytherapy↗