Biomedical subjects

J M Pow-Sang

Publications and source records attributed to J M Pow-Sang.

At least 19 recordsLinked to original sources

PubMed2004

Devastating complications after brachytherapy in the treatment of prostate adenocarcinoma.

OBJECTIVE: To report a retrospective chart review of patients who developed recto-urethral fistula (RUF) or several bladder neck contracture (BNC) recurrences after brachytherapy for treating localized prostate cancer. PATIENTS AND METHODS: In the past 3 years 18 patients with devastating complications after prostate brachytherapy were referred to our centre (RUF in 11, BNC in seven; mean age 63 years, range 60-81). All patients with RUF initially underwent diverting colostomy (six cystoprostatectomy with closure of the fistula, omental interposition and urinary diversion; one prostatectomy, bladder neck closure, fistula closure with omentum flap and continent vesicostomy). Three patients had the fistula closed with gracilis muscle flap using the York-Mason approach (one had a bladder neck closure and suprapubic tube; one elected to have no treatment). All patients with BNC had received three or more procedures to resect or incise their contracture. Four had diversion with a catheterizable segment, two used an indwelling Foley catheter and one uses intermittent catheterization. RESULTS: All six patients who had cystoprostatectomy with urinary diversion have had no recurrence of their RUF. All three treated with the York-Mason procedure healed well. One developed recurrent prostate adenocarcinoma and two a secondary neoplasia in the prostate or rectum (leiomyosarcoma and neuroendocrine, respectively). The enterocystoplasty patient developed sepsis after colostomy reversal and subsequently died. In those patients with BNC, the four who underwent urinary diversion fared well; two tolerate the indwelling catheter poorly, and the seventh uses intermittent catheterization with occasional difficulty. CONCLUSIONS: Brachytherapy with or without external irradiation can be associated with severe complications. RUF managed with aggressive anterior pelvic exenteration and urinary diversion can be associated with excellent results. The York-Mason procedure in patients with an adequate urinary continence mechanism and bladder dynamics may provide good functional results. The presence of a secondary malignancy in patients deserves further investigation. Many recurrences of a BNC tend be refractory to transurethral resection/incision; indwelling catheters are then poorly tolerated and patients may require a major reconstructive procedure.

Adenocarcinoma↗

PubMed2000

NCCN Practice Guidelines for Prostate Cancer.

Systemic therapies for prostate cancer are likely to improve, and as they do, they will have enormous impact on the treatment of high-risk and locally advanced cancers. Further technical improvements in radiotherapy and alternative local modalities, such as cryoablation, are also likely, and will bring even more options for local control. It is certain these guidelines will continue to evolve.

Evidence-Based Medicine↗

PubMed1999

Evaluation of flap valve as an alternative continence mechanism in the Florida pouch.

OBJECTIVES: To evaluate urodynamic findings in a successful flap valve (FV) continence mechanism in association with a continent colonic urinary reservoir (Florida pouch) and to compare the urodynamic findings of the FV mechanism with the doubly plicated (PI) standard anti-incontinence segment in the same reservoir. METHODS: Thirteen patients who successfully received the Florida pouch between 1988 and 1996 agreed to undergo urodynamic evaluation as part of a pilot study. Eight patients had a PI continence mechanism and a mean time from surgery of 51 months; 5 had a FV continence mechanism and a mean time from surgery of 14 months. Enterocystometry was performed with a trans-stomal Bard triple channel 7F catheter. Volume and pressure at first desire to empty (VFDE, PFDE), as well as maximal enterocystometric capacity and pressure (VMEC, PMEC), were recorded. Maximal outlet pressure (MOP) was recorded using the catheter withdrawal technique. RESULTS: PI and FV groups demonstrated the following mean values respectively: VFDE, 692.7 and 403 mL; PFDE, 19.5 and 19.2 cm H2O; VMEC, 876.5 and 515 mL; PMEC, 25.9 and 24.6 cm H2O; MOP, 57.5 and 51.2 cm H2O (reservoir empty) and 50.5 and 52.6 cm H2O (reservoir full); and functional length of outlet, 24.3 and 24.6 cm. MOP measurement demonstrated greater variability in the PI than in the FV group. CONCLUSIONS: Urodynamic comparison of these mechanisms reveals that MOP measurement was closer to the mean among FV than PI patients. In addition, the mean VFDE (692.7 mL for PI versus 403 mL for FV, P < 0.05) and the mean VMEC (876.5 mL for PI versus 515 mL for FV, P < 0.05) were significantly less in the FV group. Lower VMEC and less variability in MOP indicate that continence may be more dependent on MOP in the FV mechanism. A longer follow-up time and a larger number of patients will be of assistance in clarifying these findings.

Humans↗

PubMed1999

Predictability of PSA failure in prostate cancer by computerized cytometric assessment of tumoral cell proliferation.

OBJECTIVES: To evaluate the relationship of DNA ploidy and cell proliferation (CP) with Gleason score (GS) and clinical outcome in prostate cancer. METHODS: Sixteen patients with benign prostatic hyperplasia (BPH) and 65 patients with prostate cancer classified by GS (four groups: 2 to 4, 5 to 6, 7, and 8 to 10) were studied. All patients with carcinoma underwent prostatectomy and were separated into prostate-specific antigen (PSA) failure and nonfailure groups (failure if PSA 0.1 ng/mL or more three times after surgery). Tumoral CP (Ki-67 inmunostaining and SG2M phase) and DNA ploidy were evaluated by computerized cytometry. RESULTS: BPH were diploid with low CP (8% SG2M cells or less). Carcinomas were either diploid with high CP (greater than 8% SG2M cells) or aneuploid. CP was significantly higher (P <0.001) in tumors with GS 7 or greater than in tumors with GS less than 7 (mean percent Ki-67 cells 18.3% versus 7.8%, respectively). PSA failure increased with GS (7.1% in GS 2 to 4, 21% in GS 5 to 6, 28.6% in GS 7, and 50% in GS 8 to 10), as well as with aneuploidy (18.5% in diploid tumors versus 72.7% in aneuploid tumors). Those experiencing PSA failure had significantly higher (P <0.001) CP than those not failing (mean percent Ki-67 cells 24% and mean percent SG2M 30.4% versus 8.7% and 13.5%, respectively). Cox regression analysis showed GS, DNA ploidy, Ki-67, and SG2M to each be univariately prognostic for time to PSA failure; however, Ki-67 and SG2M were more highly significant (P <0.0001 for both) than GS (P = 0.007) or DNA ploidy (P = 0.002). After adjusting for either SG2M or Ki-67 measures of CP, neither ploidy nor GS contained additional prognostic value. CONCLUSIONS: Tumor CP and DNA ploidy can be reliably determined in prostate cancer by computerized cytometry. On the basis of our preliminary results, CP correlates well with GS and predicts PSA failure better than DNA ploidy or GS.

Aged↗

PubMed1999

Needle imaging during ultrasound-guided permanent prostate implants.

As demonstrated by water phantom experiments and clinical observations, the reverberation artifact associated with the ultrasound needle image during permanent prostate implants is extremely useful in determining precise radioactive seed positioning. It also serves as an independent quality assurance check of the number of seeds in the strand.

Brachytherapy↗

PubMed1996

Improvement in dosimetry of ultrasound-guided prostate implants with the use of multiple stabilization needles.

The use of three stabilization needles for ultrasound-guided permanent prostate implants results in better dosimetric coverage of the prostate, all other variables being equal. This technique prevents rocking motion of the prostate when anterior needles are inserted and thus improves accuracy of seed placement and shortens the length of the procedure. On post-implant CT-based dosimetric evaluation, the three stabilization needles technique provides better coverage, with the prescription isodose line encompassing 95% of the target volume compared to 90% for the implant utilizing two stabilization needles. Further improvements in the technique are currently under investigation, with the goal of consistently achieving truly "conformal anatomical prostate brachyradiotherapy."

Brachytherapy↗

PubMed1996

Ancillary techniques in the followup of transitional cell carcinoma: a comparison of cytology, histology and deoxyribonucleic acid image analysis cytometry in 91 patients.

PURPOSE: Voided urine and bladder washing cytology are used frequently in the evaluation of transitional cell carcinoma of the bladder. As part of an ongoing investigation we report on the role of deoxyribonucleic acid (DNA) image analysis cytometry as an adjunct to cytology in the followup of patients with transitional cell carcinoma. MATERIALS AND METHODS: Urine cytology and image analysis cytometry were performed independently on aliquots of voided urine, catheterized urine or bladder washings from 91 patients with previous or active transitional cell carcinoma of the bladder, and the results were compared to those of concurrent biopsy and clinical followup. RESULTS: Of 75 recurrent transitional cell carcinomas 42 were detected by cytology, while 63 and 64 were identified by image analysis cytometry and biopsy, respectively, for a sensitivity of 57, 84 and 85%, respectively. Combined cytology and image analysis cytometry detected 67 recurrences, for an overall sensitivity of 89%. Of 11 cases undetected by concurrent biopsy 9 had abnormal DNA histograms with transitional cell carcinoma at followup and 2 were DNA diploid but with grade 1 transitional cell carcinoma at followup. Of 12 cases undetected by image analysis cytometry 8 were grade 1 and 4 were grade 2 transitional cell carcinoma. CONCLUSIONS: Urine cytology and image analysis cytometry detect most recurrent tumors. Their combined use is indicated in the followup of patients with bladder transitional cell carcinoma.

Adult↗

PubMed1993

Antisense DNA inhibition of tumor growth induced by c-Ha-ras oncogene in nude mice.

Antisense DNA has shown an ability to target specific oncogene transcripts and inhibit their expression in cells, but the degree to which sustained treatment can suppress total levels of an oncogenic product and alter tumorigenesis in vivo remains to be determined. In this study, NIH-3T3 cells transformed by the activated c-Ha-ras oncogene from T24 human bladder cancer cells were treated for 3 consecutive days in vitro with an antisense DNA pentadecamer complementary to a target in the 5'-flanking region of the c-Ha-ras RNA transcript. Following antisense DNA treatment, a portion of the cells was lysed for measurement of RAS p21 while the remaining cells were evaluated for tumorigeneity by injection s.c. into athymic nude mice at a dose of 5 x 10(5) cells/mouse. The 3 days of treatment with the anti-c-Ha-ras DNA reduced RAS p21 cellular levels by more than 90% while a nonspecific control DNA reduced p21 levels by approximately 20%. Tumor growth of cells treated with anti-c-Ha-ras DNA was significantly reduced for up to 14 days following the end of treatment and implantation into the mice whereas the nonspecific control DNA had no significant effect. These effects on tumor growth were evident in two different strains of nude mice and in both males and females. It is suggested that the pronounced decrease in RAS p21 levels produced by anti-c-Ha-ras DNA resulted in a reversal of the transformed phenotype, and it is this reversal which accounts for the prolonged inhibition of tumorigenesis following antisense DNA treatment.

3T3 Cells↗

PubMed1993

Role of DNA image cytometry in the follow-up of patients with urinary tract transitional cell carcinoma.

Detection of recurrent urinary tract transitional cell carcinoma (TCC) is a frequent diagnostic challenge in exfoliative cytology because of the difficulty in distinguishing reactive changes from low grade tumors. This study evaluated the role of DNA analysis by image cytometry (ICM) as a diagnostic aid to cytology. Eighty-seven urine samples from patients with a known history of transitional cell carcinoma were examined by both cytology and ICM, and the results were compared with concurrent surgical biopsy specimens and patients' follow-up data. Twenty-seven patients were also examined by cystoscopy, and the results were compared to those of DNA analysis, cytology and biopsy. Urine samples were cytocentrifuged and stained with Papanicolaou stain for general cytology and Feulgen stain for ICM. DNA ploidy and the proliferating cell fraction (SG2M) were measured using the CAS 200 image analyzer. Among the 87 specimens included in the study, 59 were from patients considered to have recurrent disease when urine was obtained. Of the 59 recurrences, 33 were detected by cytology, 50 by ICM and 50 by biopsy, resulting in 55%, 85% and 85% sensitivity, respectively. When combined, cytology and ICM detected 53 recurrences and achieved 90% sensitivity. Nine cases originally undetected by biopsy had abnormal DNA histograms and were found to have TCC on follow-up examination. All cases undetected by ICM were low grade lesions with DNA diploidy and low proliferation. Among the 27 patients examined by cystoscopy, 14 had recurrent disease; 5, 13 and 6 of those cases were detected by cystoscopy, DNA analysis and cytology, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Carcinoma, Transitional Cell↗

PubMed1992

Conversion from external appliance wearing or internal urinary diversion to a continent urinary reservoir (Florida pouch I and II): surgical technique, indications and complications.

A total of 20 patients with diversion requiring an external appliance or internal urinary diversion underwent conversion to a continent urinary reservoir (Florida pouch I or II). All patients subsequently reported an improvement in the quality of life and expressed satisfaction with the new urinary diversion procedure. Of the patients 15 (75%) previously had an ileal conduit, while 1 (5%) had undergone ureterosigmoidostomy, 1 (5%) had cutaneous ureterostomy, 1 (5%) had a suprapubic tube, 1 (5%) had a sigmoid conduit and 1 (5%) had a cecal conduit. After the original diversion 3 patients (15%) had recurrent urinary infections, 3 had complications related to the stoma and external appliance (stenosis and skin dermatitis) and 5 (25%) had ureteral obstruction in 7 ureters. A total of 17 patients with conduits (85%) underwent conversion via different surgical technical aspects depending on the status of the intestinal segment from the conduit and the function of the ureteral reimplantation: in 14 the conduit was discarded or was used only to patch the newly created Florida I colonic pouch, while in 6 the conduit was preserved and 9 ureterointestinal reimplantations were left undisturbed (Florida pouch II). Among 7 ureters preoperatively obstructed (original diversion), reimplanting them into the pouch failed to prevent further renal damage in 5 (71%). Three renal units required nephrectomy, 2 kidneys deteriorated and 2 recovered renal function after percutaneous balloon dilation and stenting. Among 31 preoperatively nonobstructed renoureteral units (original diversion), 22 were reimplanted into the colonic reservoir. One of these units (4.2%) became obstructed postoperatively and 3 (13.5%) presently have reflux. The 10 reimplantations left undisturbed in the detubularized conduit drain satisfactorily without postoperative obstruction and in 6 reflux has not been demonstrated. Renal function (serum creatinine) is preserved in all patients but 15 (75%) have hyperchloremia of mild degree. Two patients (10%) have acidosis and 1 (5%) of these had low red blood cell folic acid. Conversion of an external or internal diversion to a continent colonic urinary reservoir (Florida pouch I or II) can be successful and improve the quality of life of the patient. The functioning renal units that were preoperatively obstructed were associated with a high failure rate (71%) after reimplantation. Metabolic alterations will require long-term followup, and are particularly worrisome in children and young adults.

Adolescent↗

PubMed1991

Intravesical bacillus Calmette-Guerin for patients with high-risk superficial bladder cancer.

Intravesical bacillus Calmette-Guérin (BCG) was employed in the treatment of 55 patients with aggressive superficial transitional cell carcinoma of the bladder (cTa, cT1, cTis). All of the patients had a previous history of recurrent superficial disease, and 41 (75%) were treatment failures following other intravesical therapy. Thirty-six (66%) patients responded to treatment, and 19 (34%) were treatment failures. Twenty-seven (66%) of 41 patients with cTa-cT1 tumors and 9 (64%) of 14 patients with cTis responded, with a mean follow-up period of 30.5 months. Disease progression was noted in 8 (15%) of the patients and muscle invasive disease in 6. Patients with a history of three or more previous events of tumor recurrence, positive urinary cytology, and multicentric disease, all fared worse than patients without these characteristics (p less than 0.05). BCG is an effective agent in controlling superficial transitional cell carcinoma of the bladder, even in a high-risk group of patients who failed previous intravesical therapy. BCG should be employed in this group of patients prior to radical surgery.

Administration, Intravesical↗

PubMed1991

Results, complications and surgical indications of the Florida pouch.

One hundred and seven patients underwent continent urinary diversion using an extended, detubularized right colonic segment as the urinary reservoir and the distal part of the ileum as a continent catheterized efferent system. This reservoir allows the accommodation of a large volume of urine; urodynamics in 28 patients demonstrated a maximum reservoir capacity varying between 550 and 1,200 milliliters (an average of 747 milliliters). The reservoir maximal volume and pressure remains unchanged in six patients studied urodynamically three to four years postoperatively. Maximal reservoir pressures ranged between 10 and 58 centimeters of H2O (an average of 35 centimeters). Of 201 ureterocolonic reimplantations, four ureters were initially reimplanted using a modified Le Duc procedure, 26 ureters were subsequently managed using the Goodwin transcolonic approach and 165 reimplantations were done with a direct (nontunneled) mucosa to mucosal anastomosis. The over-all success rates with each of the three techniques (absence of reflux and obstruction) have been 75.0, 84.7 and 87.4 per cent, respectively. However, the incidence of obstruction was 13.3 per cent for the tunneled and 4.2 per cent for the non-tunneled reimplantations. Six megaureters underwent imbrication and direct reimplantation, and three of these became obstructed. One patient died of pulmonary embolism. Medical and surgical complications markedly predominated in the group who underwent simultaneous cystectomies, and in this group, the over-all complication rate was comparable with that for previously reported series with ileal conduits. The double row plication of the distal part of the ileum and ileocecal valve allows easy catheterization every four to six hours and 105 patients (97.2 per cent) remained continent between catheterizations. The stoma is covered using a small gauze, cap or sterile adhesive strip. This protects clothing from mucus production by the stoma and an occasional episode of urinary dribbling. Seven patients required reoperation for correction of incontinence or other complications. Our satisfactory experience with these patients makes this technique an excellent approach to achieving continent urinary diversion.

Adolescent↗

PubMed1990

Transrectal ultrasound of the prostate.

One hundred and twenty-one transrectal ultrasound examinations of the prostate were performed between August and October of 1987. Indications included screening in 41 patients, evaluation of bladder outlet obstruction in 63 patients, evaluation of palpable nodules in 6 patients, and evaluation after transurethral resection of the prostate in 11 patients. A total of five patients were discovered to have prostate cancer after biopsy of a hypoechoic lesion in a normal feeling prostate by digital rectal examination. One patient was from the screening group, two patients with bladder outlet obstruction and two patients from the postransurethral resection group. All six patients with palpable nodules were diagnosed as having a cancer: Stage B2 on the rectal examination and two of the six patients were upstaged to Stage C by ultrasound criteria. In our hands transrectal ultrasound of the prostate is a valuable adjunct in the urological armamentarium with clear application in the diagnosis and staging of prostate cancer.

Adult↗

PubMed1990

Transabdominal radical nephrectomy in ninety-one consecutive patients with Wilms' tumor.

Ninety-one children that were subjected to transabdominal radical nephrectomy are reviewed. The patients' ages ranged from 20 days to 10 years. Forty cases had a right side tumor and 44 a left side tumor; bilateral tumor incidence was 7.70% (7 cases). The tumor weight incidence was 75% for greater than or equal to 500 g and 37.5% for greater than or equal to 1,000 g. Incidence of local extension of the disease was 21.98%. Intraoperative complications were 12 ruptures of the kidney capsule, 1 laceration of the cecum, 1 opening of the pleura, 1 section of the superior mesenteric artery, and 1 section of the right common iliac artery. The mortality rate in unilateral surgery, because of intraoperative massive hemorrhage, was 3/83 (3.61%). One patient with bilateral tumor died because of acute renal insufficiency and sepsis. One patient with caval thrombus which extended up to the right atrium died because of intraoperative massive pulmonary embolism.

Abdomen↗

PubMed1990

Bilateral ilioinguinal lymph node dissection in the management of cancer of the penis.

Twenty-nine patients with squamous cell carcinoma of the penis underwent bilateral ilioinguinal groin dissection 6 weeks after removal of the primary penile lesion. Eighty percent of the patients were alive and without evidence of disease at 5 years when the dissected lymph nodes were negative. When positive nodes were found, 62.5% of the patients were alive and without evidence of disease at 5 years: two of these patients had one iliac deep node positive each. The mortality rate at 5 years because of progression of disease was 6.6% when the dissected lymph nodes were negative, as compared to 37.5% when the dissected lymph nodes were positive.

Adult↗

PubMed1990

A continent colonic urinary reservoir: the Florida pouch.

A total of 92 patients underwent continent urinary diversion with an extended, detubularized right colonic segment as the urinary reservoir and the distal ileum as a continent catheterizable efferent system. In this series 65 patients were followed for 6 to 46 months (average 17 months). Our reservoir allows the accommodation of a large volume of urine; urodynamic studies in 28 patients demonstrated a maximum reservoir capacity varying between 550 and 1,200 cc (average 747 cc). Maximal reservoir pressures ranged from 10 to 58 cm. water (average 35 cm. water). Of the 127 ureterocolonic reimplantations 4 ureters were initially reimplanted with a modified Le Duc procedure, 26 ureters were managed subsequently with the Goodwin transcolonic approach and 91 reimplantations were done with a direct (nontunneled) mucosa-to-mucosa anastomosis. The overall success rates with each of the 3 techniques (absence of reflux and obstruction) were 75, 88.6 and 90.1%, respectively. Six megaureters underwent imbrication and direct reimplantation, and 3 of these (50%) became obstructed. Two converted ileal conduits were opened at the antimesenteric edge and were patched to the reservoir while the ureteroileal anastomosis was left undisturbed. One patient (1.5%) died of pulmonary embolism. Medical and surgical complications occurred only in the group who underwent simultaneous cystectomy and the over-all rate of complication was comparable to previous series with ileal conduits. The double row plication of the distal ileum and ileocecal valve allows for easy catheterization every 4 to 6 hours and 63 patients (97%) remain continent between catheterization. Four patients (6%) required reoperation for correction of incontinence or other complications. Our satisfactory experience with these patients makes this technique an excellent approach to achieving continent urinary diversion.

Colon↗

PubMed1990

Combined cystourethropexy for the treatment of type 3 and complicated female urinary incontinence.

We treated 37 women with type 3 stress urinary incontinence or with an associated complicating factor, such as morbid obesity, a large or proximal diverticulum or a urethrovaginal fistula, via combined transvaginal cystourethropexy. All women with type 3 stress incontinence had failed a previous anti-incontinence operation. Patients in both groups underwent suprapubic needle suspension and an additional bladder neck support procedure. Among 33 patients who underwent preoperative urodynamic studies 30 had stable bladders (90%), while 3 had low pressure detrusor instability (10%). The success rate in achieving continence, including cured and improved patients, was 94.6% with a followup of 3 to 72 months. Four patients (10%) required temporary intermittent catheterization for 3 to 4 weeks but none presented with long-term voiding dysfunction. The added bladder neck support improved our results in these complicated female incontinence cases compared to the standard suprapubic needle suspension procedures alone. The combined procedure currently is our method of choice for treatment of type 3 and other complicated cases of female urinary incontinence.

Adolescent↗

PubMed1989

Management of yolk sac carcinoma of the testis clinical stage I: lymphadenectomy vs. no lymphadenectomy.

Thirty seven patients with Stage I yolk sac tumor of the testis were registered at the Instituto Nacional de Enfermedades Neoplasicas (I.N.E.N.), Lima-Peru from 1962 through 1980. Eighteen patients underwent retroperitoneal Lymph node dissection. The age incidence was 5 to 29 months except for two patients 50 and 84 months of age each. Bilateral retroperitoneal lymph node dissection was performed in seventeen patients; unilateral dissection was performed in one patient. In two patients both had one positive node at lymphadenectomy (2/18: 11%). Eleven patients (61.11%) are alive and with no evidence of disease in between 7 to 26 years post lymphadenectomy. Seven patients (38.89%) died: 4/18 (22.22%) because of progression of the disease and three patients because of no neoplastic cause. Nineteen patients did not have retroperitoneal lymph node dissection: seven patients (36.84%) are alive with no evidence of disease and 12 patients (63.16%) died: 8/19 (42.10%) because of progression of the disease and 4/19 (21%) with no neoplastic disease. In conclusion, patients with localized disease (Clinical Stage I) benefit from retroperitoneal lymph node dissection when compared to a similar group of patients not submitted to lymphadenectomy.

Child, Preschool↗