Biomedical subjects

S K Shrivastava

Publications and source records attributed to S K Shrivastava.

At least 19 recordsLinked to original sources

PubMed2006

Radical radiotherapy in head and neck squamous cell carcinoma: an analysis of prognostic and therapeutic factors.

AIMS: Head and neck squamous cell carcinoma (HNSCC) continues to be a leading cancer in developing countries. Definitive radiation therapy either primary or as postoperative adjuvant is offered to most patients. We aimed to identify prognostic and therapeutic factors that affect locoregional control and survival in patients undergoing radical radiotherapy for head and neck squamous cell cancers. MATERIALS AND METHODS: A retrospective analysis of 568 previously untreated patients with squamous head and neck cancers, who received radical radiotherapy between 1990 and 1996, using local control, locoregional control and disease-free survival (DFS) as outcome measures. RESULTS: With a median follow-up of 18 months for living patients, the 5-year local control, locoregional control and DFS for all 568 patients were 53%, 45% and 41%, respectively, for all stages combined. The 5-year local control, locoregional control and DFS as per the American Joint Committee on Cancer stage grouping were 78%, 70% and 70%; 64%, 59% and 57%; 51%, 42% and 37%; and 40%, 27% and 22% from stages I to IV, respectively, with highly significant P values. Patients receiving higher doses (> or = 66 Gy) had a significantly better outcome compared with lower doses. The 5-year local control (59% vs 48%, P = 0.0015), locoregional control (47% vs 41%; P = 0.0043) and DFS (44% vs 37%; P = 0.0099) were significantly better in patients receiving > or = 66 Gy. Site of primary also affected outcome significantly, with oral cavity lesions faring badly. CONCLUSION: Tumour stage remains the most important factor affecting outcome in radical radiotherapy of HNSCC. A definite dose-response relationship exists with higher total doses, leading to better local control, locoregional control and DFS in all stages. Site of primary affects outcome too, with laryngeal primaries doing well and oral cavity cancers faring the worst.

Adult↗

PubMed2006

Peripheral dose from uniform dynamic multileaf collimation fields: implications for sliding window intensity-modulated radiotherapy.

The increase in the number of monitor units in sliding window intensity-modulated radiotherapy, compared with conventional techniques for the same target dose, may lead to an increase in peripheral dose (PD). PD from a linear accelerator was measured for 6 MV X-ray using 0.6 cm3 ionization chamber inserted at 5 cm depth into a 35 cm x 35 cm x 105 cm plastic water phantom. Measurements were made for field sizes of 6 cm x 6 cm, 10 cm x 10 cm and 14 cm x 14 cm, shaped in both static and dynamic multileaf collimation (DMLC) mode, employing strip fields of fixed width 0.5 cm, 1.0 cm, 1.5 cm, and 2.0 cm, respectively. The effect of collimator rotation and depth of measurement on peripheral dose was investigated for 10 cm x 10 cm field. Dynamic fields require 2 to 14 times the number of monitor units than does a static open field for the same dose at the isocentre, depending on strip field width and field size. Peripheral dose resulting from dynamic fields manifests two distinct regions showing a crest and trough within 30 cm from the field edge and a steady exponential fall beyond 30 cm. All dynamic fields were found to deliver a higher PD compared with the corresponding static open fields, being highest for smallest strip field width and largest field size; also, the percentage increase observed was highest at the largest out-of-field distance. For 6 cm x 6 cm field, dynamic fields with 0.5 cm and 2 cm strip field width deliver PDs 8 and 2 times higher than that of the static open field. The corresponding factors for 14 cm x 14 cm field were 15 and 6, respectively. The factors by which PD for DMLC fields increase, relative to jaws-shaped static fields for out-of-field distance beyond 30 cm, are almost the same as the corresponding increases in the number of monitor units. Reductions of 20% and 40% in PD were observed when the measurements were done at a depth of 10 cm and 15 cm, respectively. When the multileaf collimator executes in-plane (collimator 90 degrees) motion, peripheral dose decreases by as much as a factor of 3 compared with cross-plane data. The knowledge of PD from DMLC field is necessary to estimate the increase in whole-body dose and the likelihood of radiation induced secondary malignancy.

Humans↗

PubMed2005

Shock wave treatment in medicine.

Extracorporeal shock wave therapy in orthopedics and traumatology is still a young therapy method. Since the last few years the development of shock wave therapy has progressed rapidly. Shock waves have changed the treatment of urolithiasis substantially. Today shock waves are the first choice to treat kidney and urethral stones. Urology has long been the only medical field for shock waves in medicine. Meanwhile shock waves have been used in orthopedics and traumatology to treat insertion tendinitis, avascular necrosis of the head of femur and other necrotic bone alterations. Another field of shock wave application is the treatment of tendons, ligaments and bones on horses in veterinary medicine. In the present paper we discuss the basic theory and application of shock waves and its history in medicine. The idea behind using shock wave therapy for orthopedic diseases is the stimulation of healing in tendons, surrounding tissue and bones.

High-Energy Shock Waves↗

PubMed2005

Ultrasonographic changes in malignant neck nodes during radiotherapy in head and neck squamous carcinoma.

Limited information is available about the sonomorphological changes in metastatic neck nodes during radiotherapy. The aim of this study was to evaluate the pattern of sonomorphological changes in metastatic neck nodes with radiotherapy. The study population consisted of 16 consecutive patients planned for radical radiotherapy to the head and neck. All patients were subjected to four ultrasound examinations: before therapy, at 46 Gy, at the conclusion of radiation and at first follow up. A total of 59 ultrasound examinations were performed on 16 patients. The difference between the mean number of nodes detected per patient before (10.6) and after (7.8) radiation was significant (P = 0.05). Sixteen nodes were categorized as malignant at first sonography, half of which reverted back to normal by the end of radiation. Changes in the sonomorphology of malignant cervical lymph nodes occur with radiotherapy with more that half demonstrating reversion to normal pattern. Future studies correlating this with histopathology should be considered.

Aged↗

PubMed2003

Dextrans--potential polymeric drug carriers for flurbiprofen.

Dextrans have been used as carrier for flurbiprofen. Conjugates of flurbiprofen were synthesized by preparing their acylimidazol derivatives which were condensed in situ with dextrans of different molecular weight (40,000, 60,000, 110,000 and 200,000). The structures of the synthesized conjugates were confirmed by IR and NMR spectroscopy. The degrees of substitution were obtained between 8.0 to 9.5% and molecular weight was determined by Mark-Howin Sakurada viscosity equation. A hydrolysis study was performed in different buffer solutions (pH 1.2, 7.4, 9.0) and 80% human plasma (pH 7.4). The hydrolysis followed first order kinetics. Much faster hydrolysis was observed at pH 9.0 compared to buffer solution pH 7.4 and 80% human plasma (pH 7.4). The biological evaluation for acute and chronic anti-inflammatory activity was performed and the results were found to be comparable with the parent drug. The conjugates showed remarkable reduction in ulcerogenicity compared to parent flurbiprofen.

Animals↗

PubMed2003

Dextrans--potential polymeric drug carriers for suprofen.

Dextrans are clinically useful biodegradable polysaccharide macromolecules and have been utilized as carriers for suprofen. Conjugates of suprofen were synthesized by preparing their acylimidazol derivatives which were condensed in situ with dextrans of different molecular weights (40000, 60000, 110000 and 200000). The structures of the synthesized conjugates were confirmed by IR and NMR spectroscopy. The degrees of substitution obtained were between 7.5 and 9.0%. The molecular weight was determined by the Mark-Howin Sakurada viscosity equation. Hydrolysis was studied in different buffer solutions (pH 1.2, 7.4, 9.0) and 80% human plasma (pH 7.4) and followed first order kinetics. Much faster hydrolysis was observed at pH 9.0 compared to pH 7.4 buffer solution and 80% human plasma (pH 7.4). Biological evaluation for acute and chronic anti-inflammatory activity was performed and the results were found to be comparable with the parent drug. The ulcerogenic index of conjugates showed a remarkable reduction compared to the parent suprofen.

Animals↗

PubMed2002

Change in distribution & antifungal susceptibility of Candida species isolated from candidaemia cases in a tertiary care centre during 1996-2000.

BACKGROUND & OBJECTIVES: As a marked increase in the number of patients with candidaemia was reported in the first half (1991-1995) of the last decade at the Postgraduate Institute of Medical Education & Research, Chandigarh, India, the present study was aimed at determining further change if any, in the incidence and distribution of Candida species and their antifungal resistance pattern during the second half (1996-2000) of the same decade. METHODS: The patients with candidaemia were studied to determine the frequency of candidaemia and Candida species isolated during 1996-2000. One hundred Candida strains other than Pichia anomala (C. pelliculosa) were randomly selected from those isolates to evaluate antifungal susceptibility pattern against amphotericin B, 5-fluorocytosine, ketoconazole, fluconazole and itraconazole. The results were compared with our previous study. RESULTS: An increase in the number of patients with candidaemia was observed during 1996 (538) and 1997 (421) compared to 1998-2000 due to P. anomala outbreak. With the control of the outbreak, a substantial decrease in the incidence of candidaemia was observed from 1998 (251 in 1998, 122 in 1999 and 165 in 2000). A higher isolation of non-C. albicans Candida species (89.8%) was observed, with C. tropicalis being the most common (541, 36.1%) agent. No major change in the isolation rate of other non-C. albicans Candida species (C. guilliermondii, C. krusei, C. glabrata and C. parapsilosis) was observed. An emergence of resistance to amphotericin B in 15.4 per cent C. albicans, 8.1 per cent C. tropicalis and 33.3 per cent C. krusei strains was observed. An increase in resistance to ketoconazole (from 0% to 13%) and 5-fluorocytosine (from 1% to 8%) and a decrease to fluconazole (from 13% to 6%) were observed. Resistance to itraconazole was observed in 17 per cent of Candida strains by broth macro-dilution method. INTERPRETATION & CONCLUSION: A change in the isolation of Candida species was observed i.e. in the incidence and isolation of non-C. albicans Candida species. Emergence of resistance to amphotericin B and increase of resistance to most other antifungals are cause for concern.

Antifungal Agents↗

PubMed2001

Transperineal low-dose rate iridium-192 interstitial brachytherapy in cervical carcinoma stage IIB.

PURPOSE: To assess local control, survival and complications in patients with cervical carcinoma Stage IIB treated radically with transperineal Iridium-192 low-dose rate interstitial brachytherapy following external beam radiotherapy. PATIENTS AND METHODS: 65 women (age 25-70 years, mean 47 years) with cervical carcinoma Stage IIB were initially treated with external beam radiotherapy on a telecobalt or 6 MV linear accelerator to a dose of 50 Gy delivered in 5-6 weeks. After 2-3 weeks of completing external radiation, patients received interstitial brachytherapy with Iridium-192 (activity 0.5-1 mCi/cm) using a Syed-Neblett perineal template. The median dose delivered to the implant volume was 24 Gy (range 20-32 Gy) delivered at an average dose rate of 0.70 Gy/h (range 0.40-1.20 Gy/h). A point defined at 1.5 cm lateral to the central uterine tandem at the level of os was taken as a representative for assessing the dose to the cervix. Mean doses delivered by interstitial brachytherapy to point A, cervix, point B and rectum were 38 Gy, 34 Gy, 16 Gy and 16 Gy, respectively. RESULTS: At a median follow-up of 53 months, the actuarial disease free survival and overall survival for 65 patients at both 5 and 10 years was 64% and 44%, respectively. Response to radiotherapy was a strong predictor of local control with 82% of patients continuing to have pelvic control after initial complete response. Overall, nine (14%) patients had persistent disease, ten (15%) developed a central recurrence after initial control and three patients developed distant metastasis on follow-up. No patient had any immediate treatment-related complication. Late toxicity included grade I-II rectal reactions in five patients and grade IV bladder complication (vesico-vaginal fistula) in two patients. 5 years after treatment, one patient developed intestinal obstruction, which was relieved after conservative management. Two patients developed vaginal stenosis. The 5- and 10-year disease free survival was 48% in patients aged less than 45 years as compared to 80% in patients of more than 45 years (p = 0.009). Dose to the cervical point was a prognostic indicator with 5- and 10-year disease free survival of 47% in patients who received < 35 Gy in comparison to 80% in patients who had > 35 Gy (p = 0.03). There was no difference in local control and survival in patients with minimal and moderate parametrial involvement. Bulky disease (> 4 cm) at presentation and a longer gap between external radiation and brachytherapy showed a trend towards inferior local control. CONCLUSIONS: Interstitial brachytherapy after external beam irradiation in patients with cervical carcinoma Stage IIB results in acceptable local control, survival and complication rates. Increased dose to the cervical disease results in improved local control and survival and should therefore be considered while optimizing brachytherapy treatment plans. Comparison of the results with those of standard intracavitary therapy remains to be proven in a randomized trial.

Adenocarcinoma↗

PubMed2001

Primary extranodal mucosa associated lymphoid tissue (MALT) lymphoma of the prostate.

Low-grade B-cell mucosa associated lymphoid tissue (MALT) lymphoma can rarely present primarily in extranodal sites other than stomach, which is the most common site for it. Until now only four cases of primary prostatic MALTomas have been described in the literature and we report the fifth. We describe a case of primary prostatic MALToma in a 67-year-old man and the diagnosis was made on the trans-urethral resection specimen of the prostate. As the disease was limited to prostate (stage IEA), the patient was treated with external beam radiation therapy to a total dose of 4400cGy in 22 fractions. The patient achieved completed remission and has remained free of disease in the following 36 months.

Disease-Free Survival↗

PubMed2001

Solid--cystic papillary tumor of pancreas.

A case of Solid and Cystic Papillary Epithelial Tumor of Pancreas displaying low grade malignancy occurring in a 38 years old female is presented. It is a rare condition and could be diagnosed histopathologically after complete excision.

Adult↗

PubMed2000

Primary carcinoma of the vagina: Tata Memorial Hospital experience.

PURPOSE: Carcinoma of the vagina is a rare gynecological malignancy comprising approximately 2% of all the gynecological malignancies. We have analyzed the treatment outcome of the patients treated at the Tata Memorial Hospital from January 1984 to December 1993. METHODS AND MATERIALS: In this 10-year period, 134 patients of primary vaginal cancers were registered at our hospital. Of these, 75 patients received complete treatment and are analyzed. RESULTS: Disease-free survival (DFS) for the whole group is 50%, and overall survival (OAS) is 60%. Most locoregional recurrences and distant failures are noted in the 2 years following treatment. DFS at 5 years is as follows: Stage I (5 patients), Stage IIA (37 patients), Stage IIB (15 patients), Stage III (14 patients), and Stage IV (4 patients); are 40%, 55%, 60%, 50%, and 25%, respectively. The DFS for patients with complete response (42 patients) to external radiation at 5 years is 68%, with partial response (25 patients) is 35%, and with poor or no response (6 patients) is 18% (p = 0.0000). We observed that brachytherapy was an important part of the treatment, and patients who received brachytherapy (59 patients), either with a vaginal intracavitary applicator (30 patients) or interstitial implant (29 patients) had a DFS of 53% and 56%, respectively, while 15 patients who received external radiation alone had a DFS of 30%. Patients receiving brachytherapy within 4 weeks of external radiation had a DFS of 60% as compared to 30% when the interval was more than 4 weeks. CONCLUSION: The factors indicating prognosis are: site and extent of involvement, presence of lymph nodes at presentation, technique of brachytherapy, and interval between external radiation and brachytherapy.

Adolescent↗

PubMed2000

IL-12 and IL-2 potentiate the in vitro tumor-specific activity of peripheral blood cells from cervical cancer patients.

We have carried out a detailed analysis of the cellular immune functions of cervical cancer patients in comparison with healthy controls. It has been observed that the freshly isolated peripheral blood mononuclear cells (PBMC) exhibit natural cytotoxicity (NC) against a number of targets including tumor cells, mainly delivered by NK cells, which are non-adoptive and MHC unrestricted. Upon stimulation with cytokines like IL-2, IL-7, IL-12, IL-15 and interferons, PBMC acquire lymphokine activated killer (LAK) activity which enables them to lyse a wide range of targets including fresh tumor cells and virally infected cells. We compared the effect of IL-2 and IL-12 on enhancement of NC of PBMC from cervical cancer patients. IL-12 stimulated cultures (CD3+, CD56+) exhibited significant levels of tumoricidal activity. IL-2 stimulated lytic activity sustained even after 10 days while that of IL-12 stimulated cells declined after 6 days. Activation of PBMC was marked by increase in the expression of activation marker CD45RO and adhesion molecules LFA-1alpha, ICAM-1 and CD44. Addition of IL-12 to IL-2 stimulated cultures further enhanced the degree of lytic activity. Our data, thus, provide an evidence that PBMC from cervical cancer patients can be stimulated in response to cytokines and local or systemic treatment with low doses of cytokines may help to yield a better immune response against virus infected tumor cells in cervical cancer.

Adult↗

PubMed1999

Retroperitonial, teratoma as fetus in fetu--a case report.

We report a rare case of Retroperitonial teratoma containing Axial Skeleton long bone. Jaw, pelvis & scapula in a 27 yrs old male. Aberration in monozygotic twinning may rarely present as Fetus in Fetu. Rarer is presentation in Adult.

Adult↗

PubMed1996

Geometrical considerations in dose volume analysis in intracavitary treatment.

PURPOSE: The present work was aimed at to study the relationship between the volume enclosed by reference isodose surface and various geometrical parameters of the intracavitary applicator in treatment of carcinoma of cervix. MATERIAL AND METHODS: Pearshape volume of the reference isodose derived from the Total Reference Air Kerma (TRAK) and the product of its dimensions, height H, width W and thickness T which is dependent on the applicator geometry, were estimated for 100 intracavitary applications treated by Selectron LDR machine. Orthogonal radiographs taken for each patient were used for measurement of actual geometric dimensions of the applicator and carrying out the dosimetry on TP-11 treatment planning system. The dimensions H, W and T of reference isodose surface (60 Gy) were also noted. RESULTS: Ratio of the product HWT and the pearshape volume was found mainly to be a function of colpostat separation and not of other geometrical parameters like maximum vertical and anterio-posterior dimension of the applicator. The ratio remained almost constant for a particular combination of uterine tandem and colpostat. Variation in the ratios were attributed to the non-standard geometry. CONCLUSION: The ratio of the volume of reference isodose surface to the product of its dimensions in the applicator depends upon the colpostat separation.

Brachytherapy↗

PubMed1996

Design and comparison of wedge shaped midline block with rectangular block used in early stage cervical cancers.

PURPOSE: Design of an universal wedge shaped midline block for early stage cervical cancers to get uniform dose distribution around the target volume. MATERIAL AND METHODS: The method of fabrication of wedge shaped midline block is discussed for treatment of early stage cervical cancers based on the configuration of 137Cs pellets used in intracavitary applications and along with external photon beams obtained by using 60Co teletherapy machine and 6 and 10 MV linear accelerators. RESULTS: The dosimetric measurements are carried out to confirm the adequacy of thickness and shape of the block using radiation field analyzer for all the 3 energies. DISCUSSION: The dose distribution comparison has been made with wedge shaped midline block and conventional rectangular shields to show its superiority in getting homogeneous dose distribution around target volume. The shift in 184 intracavitary applications is analyzed in actual clinical applications with respect to central axis of external beams and its comparison is made with both types of blocks. With the shift of 1 cm towards lateral from midline an overdose can occur upto 12 Gy at certain points with rectangular block compared to wedge shaped midline block. CONCLUSION: Since the preparation of individual wedge shaped midline block for every application will be a difficult process for busy centers, the single wedge shaped midline block for each energy is more convenient to handle for busy centers instead of individualized compensating blocks for every intracavitary application.

Brachytherapy↗

PubMed1996

Hodgkin's disease relapse presenting as Pancoast's syndrome.

Among the various infrequent causes of Pancoast's syndrome, Hodgkin's disease is one. A 26 year old man was diagnosed as Hodgkin's disease. Five years later the disease relapsed producing Pancoast's syndrome. The importance of precise aetiological diagnosis before treatment of such cases with similar presentation is emphasized.

Adult↗

PubMed1994

Treatment volume from total reference air kerma (TRAK) in intracavitory applications and its comparison with ICRU reference volume.

PURPOSE: A systematic dosimetry study conforming to International Commission on Radiation Units and Measurements Report Number 38, was carried out for, cancer of Cervix Stage I and II cases at Tata Memorial Hospital. METHODS AND MATERIALS: The reference Volume dimension were noted for each applicator. Also 3-D dosimetry was performed for selected cases, and actual geometric volume enclosed by various isodose surfaces were obtained. A relation was derived, which gave the volume enclosed by any isodose surface as a function of total reference air kerma of the sources in the applicator. The volume enclosed by reference isodose surface was compared with the product of its dimensions height, width, and thickness. RESULTS: The volume enclosed by any isodose surface of an intracavitary application can be easily derived from total reference air kerma of the sources within the applicator. CONCLUSION: Ratio of the volume enclosed by reference isodose surface with the product of its dimensions (HWT) could be a predictive parameter for clinical outcome, besides the reference volume specified by the report.

Brachytherapy↗

PubMed1993

Therapeutic factors influencing the cosmetic outcome and late complications in the conservative management of early breast cancer.

PURPOSE: To investigate the impact of clinical and physical parameters on the cosmetic result and complications, in cancer breast treated with conservative surgery and definitive irradiation. METHODS AND MATERIALS: Between October 1980 and December 1990, 289 patients were treated with lumpectomy and/or axillary dissection, radical irradiation with or without adjuvant therapy. The radiation therapy technique consisted of external beam therapy followed by an Ir-192 implant or electron beam boost. Univariate and multivariate analysis were used to evaluate the correlation between multiple factors affecting the cosmetic outcome and the complications. RESULTS: Of 289 patients, cosmesis was evaluable in 285 and recorded as excellent to good in 226 (79%), fair in 35 (12%), and poor in 24 (9%). On multivariate analysis of these results, a high dose per fraction (p = .0018), and use of electrons as boost to the tumor bed (p = .001) were found to be significant. When patients boosted with electrons were excluded, a high boost dose (p = .0433) was also found significant. Fifteen (5%) patients developed severe late radiation sequelae and 14 (5%) moderate or severe arm edema. On multivariate analysis only dose per fraction of 2.5 Gy (p < .0001) and higher boost doses (p = .017) were significant. CONCLUSION: In 289 patients of early breast cancer treated with conservative surgery and radical irradiation, multivariate analysis suggests that higher dose per fraction with teletherapy and higher brachytherapy boost dose adversely affect cosmesis and contribute to the late complications.

Adult↗