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Dive into the research topics where Ronald K. Potkul is active.

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Featured researches published by Ronald K. Potkul.


Journal of Clinical Oncology | 2012

Lymphatic Mapping and Sentinel Lymph Node Biopsy in Women With Squamous Cell Carcinoma of the Vulva: A Gynecologic Oncology Group Study

Charles Levenback; Shamshad Ali; Robert L. Coleman; Michael A. Gold; Jeffrey M. Fowler; Patricia L. Judson; Maria C. Bell; Koen De Geest; Nick M. Spirtos; Ronald K. Potkul; Mario M. Leitao; Jamie N. Bakkum-Gamez; E.C. Rossi; Samuel S. Lentz; James J. Burke; Linda Van Le; Cornelia L. Trimble

PURPOSE To determine the safety of sentinel lymph node biopsy as a replacement for inguinal femoral lymphadenectomy in selected women with vulvar cancer. PATIENTS AND METHODS Eligible women had squamous cell carcinoma, at least 1-mm invasion, and tumor size ≥ 2 cm and ≤ 6 cm. The primary tumor was limited to the vulva, and there were no groin lymph nodes that were clinically suggestive of cancer. All women underwent intraoperative lymphatic mapping, sentinel lymph node biopsy, and inguinal femoral lymphadenectomy. Histologic ultra staging of the sentinel lymph node was prescribed. RESULTS In all, 452 women underwent the planned procedures, and 418 had at least one sentinel lymph node identified. There were 132 node-positive women, including 11 (8.3%) with false-negative nodes. Twenty-three percent of the true-positive patients were detected by immunohistochemical analysis of the sentinel lymph node. The sensitivity was 91.7% (90% lower confidence bound, 86.7%) and the false-negative predictive value (1-negative predictive value) was 3.7% (90% upper confidence bound, 6.1%). In women with tumor less than 4 cm, the false-negative predictive value was 2.0% (90% upper confidence bound, 4.5%). CONCLUSION Sentinel lymph node biopsy is a reasonable alternative to inguinal femoral lymphadenectomy in selected women with squamous cell carcinoma of the vulva.


Journal of Clinical Oncology | 1997

High-dose chemotherapy with autologous transplantation for persistent/relapsed ovarian cancer: a multivariate analysis of survival for 100 consecutively treated patients.

Patrick J. Stiff; Robert Bayer; C Kerger; Ronald K. Potkul; D Malhotra; D J Peace; D Smith; Susan G. Fisher

PURPOSE To examine the prognostic factors associated with prolonged progression-free survival (PFS) and overall survival (OS) in 100 consecutively treated women undergoing autologous stem-cell transplant for advanced ovarian cancer. PATIENTS AND METHODS From October 1989 to February 1996, we transplanted 100 patients with ovarian cancer following chemotherapy with high-dose carboplatin, mitoxantrone, and cyclophosphamide with or without cyclosporine (n = 70); melphalan and mitoxantrone with or without paclitaxel (n = 25); or other regimens (n = 5). Their median age was 48 years (range, 23 to 65), 70% had papillary serous histology, 72% had grade III tumors, 66% were platinum-resistant, and 61% had > or = 1 cm bulk. The median number of prior regimens was two (range, one to six). Univariate and multivariate analyses were performed to examine age (< v > or = mean), stage, initial bulk, histology, grade, response to initial therapy, number of prior regimens, time from diagnosis to transplant, transplant regimen, platinum sensitivity, and bulk (< v > or = 1 cm) at transplant. RESULTS The median PFS and OS times for the 100 patients were 7 and 13 months. A stepwise Cox proportional hazards model identified tumor bulk (P = .0001), and cisplatin sensitivity (P = .0249) as the best predictors of PFS. Age (P = .0017), bulk at transplant (P = .0175), and platinum sensitivity (P = .0330) provided the best prediction of OS. The median PFS and OS times for the 20 patients with platinum-sensitive, < or = 1-cm disease were 19 and 30 months. No differences in OS were seen when chemotherapy or surgery was used to achieve a minimal disease state. CONCLUSION Before consideration of high-dose therapy for recurrent/persistent advanced ovarian cancer, patients should undergo debulking surgery or chemotherapy to achieve a minimal disease state. Patients with platinum-resistant, bulky disease should not be transplanted. The optimal patients for this therapy may be those with minimal disease responsive to initial chemotherapy.


Journal of Clinical Oncology | 2005

Multicenter, Randomized Phase II Trial of Oral CI-1033 for Previously Treated Advanced Ovarian Cancer

Susana M. Campos; Oday Hamid; Michael V. Seiden; Amit M. Oza; Marie Plante; Ronald K. Potkul; Peter F. Lenehan; Eric P. Kaldjian; Mary Varterasian; Cheryl Jordan; Claudie Charbonneau; Hal Hirte

PURPOSE To evaluate the antitumor activity and toxicity of two doses of CI-1033 in patients with platinum-refractory or recurrent ovarian cancer, and to determine baseline expression of epidermal growth factor receptor in tumor cells. PATIENTS AND METHODS This phase II, open-label clinical trial evaluated CI-1033 in patients with ovarian cancer who failed prior platinum-based therapy. Two oral doses of CI-1033 were evaluated--a 50-mg and a 200--mg oral dose administered daily for 21 days in a 28-day cycle. Patients were evaluated for tumor response and toxicity; in addition, archival baseline tumor samples were analyzed by immunohistochemistry for erbB1 to erbB4 status. RESULTS One hundred five eligible patients were treated. Baseline demographic characteristics were balanced in this heavily pretreated patient population. The median number of prior chemotherapy regimens received was four. The most commonly encountered drug-related adverse events for both dose arms were gastrointestinal (diarrhea, nausea, stomatitis) toxicity, asthenia, and rash. No responses were observed. Stable disease was confirmed in 34% and 26% of patients in the 200-mg and 50-mg arms, respectively, and 1-year survival rates were 38.5% and 37.7%, respectively. Baseline erbB3 and erbB4 revealed the highest frequencies of expression, while erbB2 was the lowest. CONCLUSION CI-1033 did not show activity in unscreened patients with advanced ovarian cancer. At 50 mg/d, CI-1033 had a more favorable adverse events profile than at 200 mg/d. erbB3 and erbB4 receptors showed the highest expression in tumor samples while erbB2 revealed the least. There appears to be no association between baseline erbB expression and disease stability.


International Journal of Radiation Oncology Biology Physics | 2011

Radiation-Related Predictors of Hematologic Toxicity After Concurrent Chemoradiation for Cervical Cancer and Implications for Bone Marrow–Sparing Pelvic IMRT

Kevin Albuquerque; David Giangreco; Courtney Morrison; Mohammed Siddiqui; Jim Sinacore; Ronald K. Potkul; John C. Roeske

PURPOSE To determine factors predictive for hematologic toxicity (HT) associated with concurrent chemoradiation for Stage II through IV cervical cancer. METHODS AND MATERIALS The medical records of 40 women receiving concurrent chemoradiation for cervical cancer were reviewed. Hematologic toxicity was defined by use of Common Terminology Criteria for Adverse Events (version 3.0). Variables predicting for HT including age, body mass index, transfusions, and bone marrow volumes irradiated were included in the data analysis. RESULTS Of the patients, 13 (32.5%) had Grade 0 or 1 HT and 27 (67.5%) had Grade 2 through 4 HT (HT2+). Multiple logistic regression analysis of potential predictors showed that only the volume of bone receiving 20 Gy (V20) for whole pelvic bone tended toward significance for predicting HT2+. A strong correlation was noted between HT2+ and V20 (r = 0.8, p < 0.0001). A partitioning analysis to predict HT2+ showed a cutoff value of 79.42% (approximately 80%) for V20 of whole pelvic bone. That is, if the V20 of the whole pelvis exceeds 80%, the risk of HT2+ developing increases by a factor (odds ratio) of 4.5 (95%, confidence interval, 1.08-18.69) (p < 0.05). CONCLUSIONS We have shown a correlation between bone marrow volume radiated and development of HT. This has implications for use of pelvic intensity-modulated radiation therapy, which can potentially decrease the volume of bone marrow radiated.


Gynecologic Oncology | 2013

Is Bilateral Lymphadenectomy For Midline Squamous Carcinoma Of The Vulva Always Necessary? An Analysis From Gynecologic Oncology Group (GOG) 173

Robert L. Coleman; Shamshad Ali; Charles Levenback; Michael A. Gold; Jeffrey M. Fowler; P. Judson; Maria C. Bell; Koen De Geest; Nick M. Spirtos; Ronald K. Potkul; Mario M. Leitao; Jamie N. Bakkum-Gamez; E.C. Rossi; Samuel S. Lentz; James J. Burke; Linda Van Le; Cornelia L. Trimble

OBJECTIVE To determine which patients with near midline lesions may safely undergo unilateral groin dissection based on clinical exam and lymphoscintigraphy (LSG) results. METHODS Patients participating in GOG-173 underwent sentinel lymph node (SLN) localization with blue dye, and radiocolloid with optional LSG before definitive inguinal-femoral lymphadenectomy (LND). This analysis interrogates the reliability of LSG alone relative to primary tumor location in those patients who had an interpretable LSG and at least one SLN identified. Primary tumor location was categorized as lateral (>2cm from midline), midline, or lateral ambiguous (LA) if located within 2cm, but not involving the midline. RESULTS Two-hundred-thirty-four patients met eligibility criteria. Sixty-four had lateral lesions, and underwent unilateral LND. All patients with LA (N=65) and midline (N=105) tumors underwent bilateral LND. Bilateral drainage by LSG was identified in 14/64 (22%) patients with lateral tumors, 38/65 (58%) with LA tumors and in 73/105 (70%) with midline tumors. At mapping, no SLNs were found in contralateral groins among those patients with LA and midline tumors who had unilateral-only LSGs. However, in these patients groin metastases were found in 4/32 patients with midline tumors undergoing contralateral dissection; none were found in 27 patients with LA tumors. CONCLUSION The likelihood of detectable bilateral drainage using preoperative LSG decreases as a function of distance from midline. Patients with LA primaries and unilateral drainage on LSG may safely undergo unilateral SLN.


Journal of Immunotherapy | 2000

Cervical cancer cells induce apoptosis of cytotoxic T lymphocytes.

Diana N. Contreras; Peter H. Krammer; Ronald K. Potkul; Ping Bu; Juan Luis Rossi; Andreas Kaufmann; Lutz Gissmann; Liang Qiao

The goal of immunotherapy is to eliminate tumors by generating tumor-specific cytotoxic T lymphocytes (CTLs) in patients or by adoptively transferring ex vivo-activated CTLs into patients. Clinical trials have shown that tumor-specific CTLs often disappear before tumors are completely eliminated. In this study, the authors show that CTLs specific for cervical tumor cells undergo apoptosis after they are co-cultured with cervical tumor cells. The established cervical tumor cell lines and cervical cancer tissues express CD95 (Fas/Apo-1) ligand. The tumor cell-induced T-cell apoptosis can be blocked by an inhibitory anti-CD95 (APO-1/Fas) antibody, indicating that tumor cells induce apoptosis of CTLs through CD95-CD95 ligand interaction. Addition of interleukin-2 (IL-2) and IL-7 into the culture rescues the CTL from tumor cell-induced apoptosis. The rescued T cells retain their full antitumor cytotoxicity. These data suggest that human cervical tumor cells might actively down-regulate a cellular immune response by inducing apoptosis of specific T cells during immunotherapy. Local use of IL-2 and IL-7 as adjuvants may promote survival of the CTL and, thus, enhance the efficacy of immunotherapy.


Intervirology | 2002

Comparison of human papillomavirus type 16 L1 chimeric virus-like particles versus L1/L2 chimeric virus-like particles in tumor prevention.

Mark T. Wakabayashi; Diane M. Da Silva; Ronald K. Potkul; W. Martin Kast

Chimeric human papillomavirus (HPV) virus-like particles (cVLPs) with the HPV16 E7 antigen fused to either the major capsid protein, L1, or the minor capsid protein, L2, have been used independently to protect against the formation of HPV-induced tumors in animal models. However, the advantages and disadvantages of both types of particles with respect to production and vaccine efficacy have never been analyzed. Therefore, in this study, we compared cVLPs with the HPV16 E7 antigen fused to L1 versus cVLPs with E7 fused to L2 with respect to their ability to protect mice from tumor challenge. The first 57 amino acids of E7 were used to overcome the size limitation and limited VLP production imposed by inserting polypeptides into L1 cVLPs. C57BL/6 mice were immunized with the above cVLPs at various doses. Tumor challenge was then performed with HPV16 E7-positive TC-1 cells. HPV16 L1-E7(1–57) was superior to HPV16 L1/L2-E7(1–57) in eliciting tumor protection at equivalent doses, although both types of particles were able to protect mice. Both cVLPs induced a specific cytotoxic T lymphocyte (CTL) response to the H2-Db-restricted E7 peptide (E749–57) as determined by an ELISPOT assay and tetramer staining; however, immunization with the L1-E7(1–57) cVLPs resulted in twofold higher CTL precursor frequencies. Our results demonstrate that cVLPs with the antigen fused to L1 are a more efficient vaccine with respect to tumor prevention than cVLPs with the antigen fused to L2. At the same time, however, L1 cVLPs are limited by the size of the antigen that can be incorporated and in the amount of cVLP that can be obtained from cultures when compared to L1/L2 cVLPs. This balances out their superior ability to induce protective immunity.


American Journal of Surgery | 2008

Hepatic resection for recurrent metastatic ovarian cancer

Gerard J. Abood; Matthew Bowen; Ronald K. Potkul; Gerard V. Aranha; Margo Shoup

BACKGROUND The role for liver resection in metastatic ovarian cancer has not been defined. The aim of the current study was to investigate the validity of hepatic resection as a treatment option in metastatic ovarian cancer. METHODS Retrospective review of a single institutions experience of patients undergoing hepatic resection for metastatic ovarian cancer from 1998-2006. RESULTS Ten patients underwent resection for metastatic ovarian cancer. Primary tumor type included serous cystadenocarcinoma (n = 8), granulosa cell (n = 1), and yolk sac (n = 1). Median disease-free interval was 48 months. Liver resections included trisegmentectomy (n = 4), lobectomy (n = 4), and bisegmentectomy(n = 1). Additional surgeries included diaphragm resection (n = 60), bowel resection, (n = 30), and adrenalectomy (n = 10). The median overall survival following liver resection was 33 months. CONCLUSION Liver resection for metastatic ovarian cancer is safe and is associated with long-term survival in some patients. Larger analysis may lead to the identification of prognostic factors associated with improved outcomes.


Journal of Contemporary Brachytherapy | 2017

How one institution overcame the challenges to start an MRI-based brachytherapy program for cervical cancer

Matthew M. Harkenrider; Steven M. Shea; Abbie M. Wood; Bonnie Chinsky; Amishi Bajaj; Michael Mysz; Joseph H. Yacoub; Ari Goldberg; Margaret Liotta; Ronald K. Potkul; Murat Surucu; John C. Roeske; William Small

Purpose Adaptive magnetic resonance imaging (MRI)-based brachytherapy results in improved local control and decreased high-grade toxicities compared to historical controls. Incorporating MRI into the workflow of a department can be a major challenge when initiating an MRI-based brachytherapy program. This project aims to describe the goals, challenges, and solutions when initiating an MRI-based cervical cancer brachytherapy program at our institution. Material and methods We describe the 6-month multi-disciplinary planning phase to initiate an MRI-based brachytherapy program. We describe the specific challenges that were encountered prior to treating our first patient. Results We describe the solutions that were realized and executed to solve the challenges that we faced to establish our MRI-based brachytherapy program. We emphasize detailed coordination of care, planning, and communication to make the workflow feasible. We detail the imaging and radiation physics solutions to safely deliver MRI-based brachytherapy. The focus of these efforts is always on the delivery of optimal, state of the art patient care and treatment delivery within the context of our available institutional resources. Conclusions Previous publications have supported a transition to MRI-based brachytherapy, and this can be safely and efficiently accomplished as described in this manuscript.


Journal of Contemporary Brachytherapy | 2012

Vaginal cuff dehiscence after intracavitary brachytherapy for endometrial cancer

Kevin Albuquerque; Karan Shah; Ronald K. Potkul

We describe 2 unusual cases of vaginal dehiscence after intracavitary brachytherapy performed following robotic laparoscopic hysterectomy (RLH) along with their management. This unusual complication, which may be more common because of the robotic procedures, can be prevented by careful examination and possible delay of the onset of brachytherapy, if indicated. Our report reviews techniques of avoiding this complication and suggests that these complications should be discussed with the patients.

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Kevin Albuquerque

University of Texas Southwestern Medical Center

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Margaret Liotta

Loyola University Chicago

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William Small

Loyola University Chicago

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Patrick J. Stiff

Loyola University Medical Center

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Michael Mysz

Loyola University Chicago

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Murat Surucu

Loyola University Chicago

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Abigail Winder

Loyola University Chicago

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