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Biomedical subjects

R A Potish

Publications and source records attributed to R A Potish.

At least 19 recordsLinked to original sources
PubMed1997

Phase I trial of taxol as a radiation sensitizer with cisplatin in advanced cervical cancer.

OBJECTIVE: The aim of this study was to determine tolerable doses and potential toxicities of taxol, administered weekly, with concomitant cisplatin and radiation therapy in advanced cervical cancer. METHODS: Patients with cervical cancer, either with evidence of distant metastatic disease at presentation or otherwise at high risk for recurrent disease, were eligible for this phase I study. Taxol was administered weekly as a 3-hr intravenous infusion in addition to the prescribed radiation therapy. The starting dose was 10 mg/m2/week and escalated at 10 mg/m2/week increments if tolerated by successive cohorts of three new patients. Cisplatin was given every 3 weeks at 50 mg/m2. Chemotherapy was continued until radiation was completed. For each patient quality of life was assessed weekly during therapy. RESULTS: Sixteen patients, undergoing a total of 102 cycles, have been enrolled. Dose escalation of taxol from 10 mg/m2/week to 50 mg/m2/week was well tolerated, with no significant change in quality of life during therapy. Two radiation fractions (0.5%) were delayed due to toxicity from this chemotherapy regimen. Of 102 cycles, 6 resulted in grade 2 and 1 in grade 3 neutropenia, and no patient developed >grade 2 anemia or thrombocytopenia. Three patients developed GI-related toxicities and 1 patient presented with urosepsis during treatment. There was a 93% response rate to this regimen, with 10 patients (63%) presently having no evidence of disease. CONCLUSIONS: This study has demonstrated that up to 50 mg/m2/week of taxol is well tolerated in patients undergoing radiation therapy for advanced cervical cancer. A phase II trial will assist in determining the efficacy of taxol as a radiation sensitizer in these patients.

Adult↗
PubMed1996

Improved dose distribution with a universal acrylic breast compensator.

Wedge filters frequently do not provide optimal distribution in the chest wall, lung, and areolar-nipple complex because they extend through the entire width of tangential radiation fields for breast cancer. In addition, medial wedge filters increase dose to the contralateral breast. In order to overcome these shortcomings, a new method of acrylic compensation was investigated. A universal acrylic breast compensator (ABC) was designed, with patient data, to extend anteriorly from the central axis. To accurately display build-up data, the ABC was entered into the treatment planning system as a wedge filter. Dose homogeneity within the compensated breast, chest wall, and lung volumes was assessed using 3-D planning and dose volume histograms. Dose to the contralateral breast was evaluated using thermoluminescent dosimetry in a polystyrene phantom. Opened, wedged, and compensated conditions were irradiated using the above described techniques. Due to lack of extension of the ABC posteriorly to the central axis (allowing lung inhomogeneity to correct for increased patient thickness), ABCs reduced the high dose regions in the chest wall and lung as compared to wedge filters. ABCs reduced hot spot in the areolar-nipple complex more efficiently as compared to wedge filters. ABCs also reduced dose to the contralateral breast by more than 20% relative to wedge filters. Wedge filters can be inefficient because of lung transmission and contour topography. Excessive dose to the chest wall, lung, and areolar-nipple complex, and contralateral breast can be alleviated with the use of a universal acrylic breast compensator. Its convenience and dosimetric advantages both in treatment planning and daily application offer a useful tool in the management of breast cancer.

Acrylic Resins↗
PubMed1994

Radical vulvectomy with postoperative irradiation for vulvar cancer: therapeutic implications of a central block.

PURPOSE/OBJECTIVE: To report the long-term results of vulvectomy, node dissection, and postoperative nodal irradiation using a midline vulvar block in patients with node positive vulvar cancer. METHODS AND MATERIALS: From 1971 through 1992, 27 patients with carcinoma of the vulva and histologically involved inguinal lymph nodes were treated postoperatively with radiation therapy after radical vulvectomy and bilateral lymphadenectomy (n = 25), radical vulvectomy and unilateral lymphadenectomy (n = 1), or hemivulvectomy and bilateral lymphadenectomy (n = 1). Federation Internationale de Gynecologic et d'Obstetrique stages were III (n = 14), IVA (n = 8), and IVB (n = 5) squamous cell carcinoma. Inguinal lymph nodes were involved with tumor in all patients (average number positive = 4, range 1-15). Postoperative irradiation was directed at the bilateral groin and pelvic nodes (n = 19), unilateral groin and pelvic nodes (n = 6), or unilateral groin only (n = 1). These 26 patients had the midline blocked. In addition, one patient received irradiation to the entire pelvis and perineum. Doses ranged from 10.8 to 50.7 Gy (median 45.5) with all patients except 1 receiving > or = 42.0 Gy. RESULTS: Actuarial 5-year overall survival and disease-free survival estimates were 40% and 35%, respectively. Recurrences developed in 63% (17/27) of the patients at a median of 9 months from surgery (range 3 months to 6 years) and 15 of these have died; two patients with recurrences are surviving at 24 and 96 months after further surgery and radiation therapy. Central recurrences (under the midline block) were present in 13 of these 17 patients (76%), either as central only (n = 8), central and regional (n = 4), or central and distant (n = 1). Additionally, three patients developed regional recurrences and one patient developed a concurrent regional and distant relapse. One patient developed a squamous cell cancer of the anus under the midline block 54 months after the initial vulvar cancer and an additional patient developed transitional cell carcinoma of the ureter (outside the radiation field) 12 months after diagnosis. Factors associated with a decreased relapse-free survival included increasing Federation Internationale de Gynecologic et d'Obstetrique stage (p = 0.01) and invasion of the tumor into the subcutaneous (SC) fat or deep soft tissue (p = 0.05). Chronic lower extremity edema developed in four patients, but there have been no other complications. CONCLUSIONS: Radical vulvectomy has often been considered sufficient central treatment for vulvar carcinoma, with postoperative irradiation directed only to the nodes. Although designed to protect the radiosensitive vulva, use of a midline block in this series resulted in a 48% (13/27) central recurrence rate, much higher than the 8.5% rate previously reported with this technique. Routine use of the midline block should be abandoned and, instead, postoperative irradiation volumes should be tailored to the individual patient.

Adult↗
PubMed1994

Erythropoietin increases hemoglobin during radiation therapy for cervical cancer.

PURPOSE: Anemia during radiation therapy independently predicts poor outcome in patients with cervical cancer. Despite a randomized trial demonstrating red cell transfusions improve local control and survival, many patients are not transfused due to toxicity concerns. This study evaluates the efficacy of recombinant human erythropoietin (r-HuEPO) in reversing anemia in patients undergoing radiation therapy. METHODS AND MATERIALS: Twenty patients with criteria of anemia (Hgb < 12.5 g/dL) and surgically staged cervical cancer FIGO stages IB (n = 7), IIA (n = 1), IIB (n = 9), and IIIB (n = 3), ranging in ages from 23-75 years (median 43), were included in this Phase I/II study. Fifteen were treated with r-HuEPO (200 U/kg/day) and ferrous sulfate 5-10 days prior to initiation of external beam radiation therapy, continuing until Hgb was < or = 14 g/dL or completion of radiation therapy. Five patients were treated with ferrous sulfate alone. An additional 61 historical controls meeting eligibility criteria were analyzed. All received external beam radiation therapy and two intracavitary cesium applications. Cisplatinum chemotherapy (20 mg/m2/week) was given as a radiosensitizer in 14 r-HuEPO patients, 4 concurrent controls, and 17 historical controls. RESULTS: A marked reticulocytosis was seen in the r-HuEPO group, but not the study controls. In the r-HuEPO group, the mean +/- SD serum Hgb rose + 30% over the course of radiation therapy from a baseline of 10.3 +/- 1.04 g/dL to 13.2 +/- 1.7 g/dL. Average increase in Hgb was 0.5 g/dL per week. Average Hgb during RT was 13.4 g/dL. In study and historical controls, mean initial Hgb levels were 10.7 +/- 1.04 g/dL and 11.1 +/- 1.3g/dL, respectively, remaining unchanged over the course of radiation therapy. Average Hgb levels during radiation therapy were 11.1 g/dL in study controls and 11.4 g/dL in historical controls, significantly lower than r-HuEPO patients (p = 0.0001). Erythropoietin was well tolerated. There were no significant differences in white blood counts (p = 0.6) or platelet counts (p = 0.4) between r-HuEPO patients and both control groups. No patients had blood pressure changes during r-HuEPO therapy. The only possible side effect was deep venous thrombosis, occurring in two patients who were withdrawn from r-HuEPO therapy. Two additional patients developed deep venous thrombosis 9 and 10 days after radiation therapy and r-HuEPO were completed. CONCLUSION: Erythropoietin appears to be both safe and effective at raising Hgb levels in anemic cervical cancer patients receiving radiation therapy and chemotherapy.

Adult↗
PubMed1993

On the lack of demonstrated clinical benefit of neoadjuvant cisplatinum therapy for cervical cancer.

PURPOSE: This study ascertains the benefit and detriment of cis-platinum-based regimes for advanced cervical cancer using standard response parameters as well as a methodology to separate potential effects of radiosensitization and effects of control of occult systemic metastases. MATERIALS AND METHODS: In addition to conventional response criteria used to analyze three recently published randomized studies, the efficacy of neoadjuvant chemotherapy is measured with a statistical model to calculate potential improvement in survival offered by perfect local and distant control. RESULTS: Neoadjuvant chemotherapy either did not affect or it impaired survival in the three trials. Evidence of altered failure patterns was obtained. In particular, local control was compromised by neoadjuvant chemotherapy. CONCLUSION: Failure patterns are altered by treatment as well as by standard prognostic factors. Neoadjuvant chemotherapy may decrease survival. Possible reasons include the limited efficacy of cis-platinum alone and in combination with other therapeutic agents, accelerated repopulation caused by neoadjuvant therapy, delay in initiation of radiotherapy by neoadjuvant chemotherapy, low statistical power of published studies, and tumor heterogeneity. Curative modalities such as surgery and radiotherapy must not be compromised by neoadjuvant chemotherapy.

Chemotherapy, Adjuvant↗
PubMed1993

Influences on inferences. Effect of errors in data on statistical evaluation.

BACKGROUND: Inadvertent random and systemic errors introduced into data sets and manipulation of data are well-defined sources of discrepancies in statistical evaluation of clinical trials. In this study, the authors show the influence of errors on the widely used statistical result, P values. METHODS: Using data from a retrospective study of patients with Hodgkin disease treated at the University of Minnesota between 1970 and 1984 and observed to 1988, we introduced various errors into the data to study the impact on results. RESULTS: Inadvertent random and systemic errors affect statistical results. Data entry and transcription errors, vague definitions of endpoints and prognostic factors, and the omission and selection of patients are examples of frequent errors that affect statistical evaluation. CONCLUSION: The results and inferences of many studies are sensitive to systemic errors and data manipulation. Great care must be given to the clear definitions of terms, exclusion and inclusion criteria, group assignments, treatment protocols, and the subgroups on which statistical analysis is performed. Clinicians and statisticians must work together to improve the performance and interpretation of clinical trials.

Clinical Trials as Topic↗
PubMed1992

Factors predictive of completion of treatment and survival after palliative radiation therapy.

Ninety-seven patients who underwent radiation treatment for metastatic carcinomas and sarcomas were evaluated to define prognostic factors that may reliably help determine survival and probability of completing a course of palliative radiation therapy. Actuarial and logistic models were used for analysis. Predictor variables included age; sex; symptoms; primary site of disease; pathologic diagnosis; prior metastatic disease, treatment, and response; solitary versus multiple metastatic sites; location of metastasis; status of primary lesion; interval between initial diagnosis and treatment for metastatic disease; and Karnofsky performance score (KPS). The interval between primary diagnosis and metastatic treatment, and KPS, were significant variables for 22 patients (23%) who failed to complete their planned radiation treatment. KPS was consistently significant for probability of survival at 2-, 4-, 8-, and 16-month intervals. At 8 months and 16 months, site of primary disease was significant, and at 16 months, solitary site of metastasis was also significant. Conventional factors, especially KPS, are useful in predicting the likelihood of completing radiation therapy and of subsequent survival for patients undergoing palliative treatment.

Adult↗
PubMed1991

Perioperative morbidity and mortality of gynecologic brachytherapy.

The incidence and nature of perioperative complications associated with gynecologic brachytherapy applications were determined in 462 implants performed on 327 patients with cervical, endometrial, or vaginal cancer from 1986 to 1988. Twenty-one patients (6.4%) had life-threatening complications, including cardiac (16 patients), thromboembolic (4 patients), and pulmonary (1 patient) events. Three complications (0.9%) were fatal within the first 30 days, and two patients died of delayed sequelae of perioperative complications; thus, there was an overall 1.5% mortality rate. Patients experiencing life-threatening complications tended to be older (P = 0.0002), and to have a history of cardiac disease (P = 0.0002) and an increased American Society of Anesthesiology (ASA) score (P = 0.003). Logistic analysis demonstrated that a history of cardiac disease and increased age were independent predictors of life-threatening complications (P = 0.01). Careful patient selection and intensive perioperative care of the high-risk patient may prove to substantially diminish these complications.

Adult↗
PubMed1991

Concomitant whole-abdominal radiation and intraperitoneal chemotherapy in advanced ovarian carcinoma. A pilot study.

Because the use of cisplatin-based chemotherapy for ovarian carcinoma has not significantly improved 5-year survival rates compared with either whole-abdominal radiation (WAR) or single-agent chemotherapy, a pilot study was begun to assess the feasibility of concomitant radiation and chemotherapy. Eleven previously untreated patients with Stages III and IV ovarian carcinoma were treated concomitantly with 2000 cGy of WAR and intraperitoneal (IP) cisplatin followed by additional IP cisplatin after debulking surgery. Toxicity was moderate to severe. Sixty-four percent of patients had Grades 3 to 4 hematologic toxicity, and 36% required hospitalization for sepsis during WAR/IP cisplatin. Hematologic toxicity was less pronounced during IP cisplatin alone. All patients experienced moderate gastrointestinal toxicity. The average percentage of total body weight lost was 13.5%. Fifty-five percent of all patients demonstrated a complete clinical response to therapy, and patients with minimal postoperative residual disease fared better. One patient with persistent disease had acute nonlymphocytic leukemia (ANLL) 24 months after initial diagnosis. No patients with residual disease greater than 20 mm survived, while 50% of patients with less than 20 mm are clinically free of disease. Toxicity appears to be additive with the combination of WAR and IP cisplatin. Therapeutic efficacy was comparable with standard chemotherapy regimens, but no therapeutic or survival advantages were demonstrated with the use of this treatment protocol.

Adult↗
PubMed1991

The provision of a uniform vaginal surface dose rate by a novel afterloading cylinder.

The administration of a uniform dose rate to the vaginal surface is important in the management of endometrial, cervical, and vaginal malignancies. Unfortunately, conventional vaginal cylinders fail to provide this uniformity, and although dome cylinders do so, they require specialized 137Cs sources. Thus, a new acrylic vaginal cylinder has been developed to use with standard 137Cs sources and provides a uniform dose rate independent of vaginal size. Each contoured cylinder follows a particular isodose line. A metal ring is used to secure the device to minimize vulvar trauma associated with other vaginal cylinders. The construction and use of a set of these cylinders has allowed determination of their utility and limitations, which will be discussed in detail. Although these applicators do not completely replace conventional cylinders, they do offer a useful addition to the brachy-therapeutic armamentarium.

Brachytherapy↗
PubMed1991

The integration of whole abdominal radiotherapy and intraperitoneal cisplatin into the primary management of advanced ovarian carcinoma.

Eleven women with Stages III and IV epithelial ovarian carcinomas were entered into a protocol consisting of concurrent whole abdominal radiotherapy and intraperitoneal cisplatin followed by additional intraperitoneal cisplatin. The entire abdomen received 20 Gy in 20 fractions with no renal or hepatic shielding. Intraperitoneal cisplatin dosage was 20 mg/m2 weekly during radiation and 90 mg/m2 monthly thereafter for an additional three courses. Patients with Stages IIIC and IV had a median survival of 18 months and a two-year actuarial survival of 32%. Primary failure sites were the abdomen, pleura, and lymph nodes. Acute toxicity during radiotherapy was comparable to patients treated with radiation alone. No chronic renal, hepatic, or enteric complications were observed. Although the protocol did not have substantial efficacy in advanced disease, its toxicity was moderate enough to consider its use in less advanced cancers with peritoneal metastases. In particular, the protocol can be considered for women with ovarian cancer with no gross residuum and for women with papillary serous carcinoma of the uterine corpus.

Antigens, Tumor-Associated, Carbohydrate↗
PubMed1990

The interplay of local and distant control in the cure of cervical cancer.

From 1978 to 1986, 183 women with cervical cancer received definitive radiation therapy after extraperitoneal surgical staging. Relapse-free rates were strong functions of pelvic lymph node metastases and cervical size. The recurrence distribution consisted of 4% isolated local, 13% isolated distant, and 17% combined local and distant failures. With the assumption of independent local and distant failure probabilities, Suit et al.'s method was extended to assess potential improvement in cure attainable with perfect local and distant control, yielding local (LSA) and distant (DSA) survival advantages of 17% and 28%. Various subsets of clinical stage, cervical size, pelvic node metastases, periaortic metastases, and peritoneal metastases had LSA from 12% to 27% and DSA from 12% to 71%. For any prognostic group, LSA never exceeded DSA, showing that effective systemic therapy would have a greater impact on improving survival than would advances in local and regional tumor control. Therapeutic implications and limitations of the extended LSA-DSA model are discussed. This form of analysis can be used to guide the intensity of local and distant treatment to maximize the cure of the patient with cancer.

Adult↗
PubMed1990

Surgical intervention following multimodality therapy for advanced cervical cancer.

From 1978 through 1986, 183 women with cervical carcinomas underwent pretreatment extraperitoneal surgical staging followed by definitive radiation therapy. Overall 10-year actuarial relapse-free and survival rates were both 64%. There were a 20.2% overall incidence and 31.6% actuarial incidence of patients with subsequent abdominal surgery. Of the 47 total surgical procedures, most frequent were 15 repairs of radiation-related bowel injury (11 patients), 11 colostomies for tumor-related obstruction or fistula and 10 explorations for possible exenteration. Only one exenteration could be performed. Other operations consisted of 5 hysterectomies, 3 negative explorations for suspected recurrence, 1 cholecystectomy, 1 small bowel obstruction following surgical staging, and 1 sigmoid resection for colon cancer. Seven patients had multiple operations. Logistic analysis revealed cervix size, pelvic node status, periaortic lymph node status, and thin physique to be significant predictors of overall recurrence, while cervix size was the only significant predictor of exploration for exenteration. Tumor-related colostomies and radiation complications tended to occur in lower and higher clinical stages, respectively. There was a trend toward greater survival in patients with surgery for radiation complications.

Adult↗
PubMed1990

The effect of applicator geometry on dose specification in cervical cancer.

The effect of variation of applicator geometry on classic parameters of dose specification was studied in 90 Fletcher-Suit radium applications in women with cervical cancer. Five statistically significant factors were identified by multiple linear regression analysis and quantified: mg of radium in the colpostats, mg of radium in the tandem, lateral displacement of the colpostats in the frontal plane, vertical separation between the colpostat and tandem sources, and anterior-posterior displacement of the colpostats relative to the tandem. These factors were used to predict "traditional" (i.e., bladder, rectum, and point A) and ICRU dose specification parameters as a function of applicator geometry. Applicator geometry had little effect on the product of ICRU volume specification components, but it greatly affected the individual ICRU components and "traditional" calculation points. Linear regression equations were generated to predict the magnitude of such changes so that the effects of variations in applicator geometry at various prescription points could be predicted radiographically, with subsequent confirmation by computerized dosimetry. Although such regression equations do not replace 3-dimensional computerized dosimetry, they aid applicator placement and treatment planning.

Brachytherapy↗
PubMed1990

Enteric morbidity of postoperative pelvic external beam and brachytherapy for uterine cancer.

From 1970 through 1986, 219 women received postoperative pelvic external beam therapy and vaginal radium or cesium for uterine cancer. Prescribed external beam and total vaginal surface doses ranged from 38 to 51 Gy and from 70 to 119 Gy, respectively. Severe enteric morbidity developed in 7.8% of patients (15 small bowel, 1 sigmoid, 1 rectal). Complications occurred more frequently in patients with pelvic lymph node sampling at hysterectomy, abdominal surgery prior to hysterectomy, and low body weight. Logistic analysis demonstrated no significant effect of pelvic external beam dose, vaginal surface boost dose, or milligram hours. Five and 10-year overall survival rates were 85% and 74%, respectively. There were two proximal and one distal vaginal recurrences. Recommendations for avoiding complications are presented.

Adult↗
PubMed1990

Multimodality therapy for advanced and recurrent vulvar squamous cell carcinoma. A pilot project.

From 1985 to 1989 eight women with advanced or recurrent vulvar carcinoma were treated at the Women's Cancer Center of the University of Minnesota Hospital and Clinic. Each received a combination of 5-fluorouracil, mitomycin C and cisplatin during radiotherapy. Five of the eight women who underwent posttreatment radical vulvectomy had acceptable operative morbidity. Six patients experienced a complete clinical response. Of them, one had microscopic residual disease in the surgical specimen. One patient with recurrent vulvar carcinoma experienced progression of disease on therapy. One death was attributable to chemotherapy toxicity, and two patients died of intercurrent disease. The overall survival rate at 27 months was 33%. This multimodality approach to the treatment of advanced vulvar carcinoma should be considered when designing a therapeutic approach to treating extensive or resistant vulvar carcinoma.

Aged↗