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Dive into the research topics where Joseph C. Poen is active.

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Featured researches published by Joseph C. Poen.


Journal of Gastrointestinal Surgery | 2001

Preoperative chemoradiation for marginally resectable adenocarcinoma of the pancreas

Vivek K. Mehta; George A. Fisher; Ford Ja; Joseph C. Poen; Mark A. Vierra; Harry A. Oberhelman; John E. Niederhuber; J.A. Bastidas

Only 10% to 20% of patients with pancreatic cancer are considered candidates for curative resection at the time of diagnosis. We postulated that preoperative chemoradiation therapy might promote tumor regression, eradicate nodal metastases, and allow for definitive surgical resection in marginally resectable patients. The objective of this study was to evaluate the effect of a preoperative chemoradiation therapy regimen on tumor response, resectability, and local control among patients with marginally resectable adenocarcinoma of the pancreas and to report potential treatment-related toxicity. Patients with marginally resectable adenocarcinoma of the pancreas (defined as portal vein, superior mesenteric vein, or artery involvement) were eligible for this protocol. Patients received 50.4 to 56 Gy in 1.8 to 2.0 Gy/day fractions with concurrent protracted venous infusion of S-fluorouracil (250 mg/m2/day). Reevaluation for surgical resection occurred 4 to 6 weeks after therapy. Fifteen patients (9 men and 6 women) completed preoperative chemoradiation without interruption. One patient required a reduction in the dosage of S-fluorouracil because of stomatitis. Acute toxicity from chemoradiation consisted of grade 1 or 2 nausea, vomiting, diarrhea, stomatitis, palmar and plantar erythrodysesthesia, and hematologic suppression. CA 19-9 levels declined in all nine of the patients with elevated pretreatment levels. Nine of the 1.5 patients underwent a pancreaticoduodenectomy, and all had uninvolved surgical margins. Two of these patients had a complete pathologic response, and two had microscopic involvement of a single lymph node. With a median follow-up of 30 months, the median survival for resected patients was 30 months, whereas in the unresected group median survival was 8 months. Six of the nine patients who underwent resection remain alive and disease free with follow-up of 12, 30, 30, 34, 39, and 72 months, respectively. Preoperative chemoradiation therapy is well tolerated. It may downstage tumors, sterilize regional lymph nodes, and improve resectability in patients with marginally resectable pancreatic cancer. Greater patient accrual and longer follow-up are needed to more accurately assess its future role in therapy.


Computer Aided Surgery | 2000

Image-guided radiosurgery for the spine and pancreas.

Martin J. Murphy; John R. Adler; Mohan Bodduluri; John Dooley; Kenneth M. Forster; Jenny Hai; Quynh T. Le; Gary Luxton; David P. Martin; Joseph C. Poen

A robotic image-guided radiosurgical system has been modified to treat extra-cranial sites using implanted fiducials and skeletal landmarks to locate the treatment targets. The system has been used to treat an artero-venous malformation in the cervical spine, a recurrent schwannoma of the thoracic spine, a metastatic adenocarcinoma of the lumbar spine, and three pancreatic cancers. During each treatment, the image guidance system monitored the position of the target site and relayed the target coordinates to the beam-pointing system at discrete intervals. The pointing system then dynamically aligned the therapy beam with the lesion, automatically compensating for shifts in target position. Breathing-related motion of the pancreas lesions was managed by coordinating beam gating with breath-holding by the patient. The system maintained alignment with the spine lesions to within +/- 0.2 mm on average, and to within +/- 1 mm for the pancreatic tumors. This experience has demonstrated the feasibility of using image-guided robotic radiosurgery outside the cranium.


Neurosurgery | 1999

Fractionated stereotactic radiosurgery and preservation of hearing in patients with vestibular schwannoma: a preliminary report.

Joseph C. Poen; Alexandra J. Golby; Kenneth M. Forster; David P. Martin; Daniel M. Chinn; Steven L. Hancock; John R. Adler

OBJECTIVE Microsurgery and stereotactic radiosurgery (SRS) for vestibular schwannomas are associated with a relatively high incidence of sensorineural hearing loss. A prospective trial of fractionated SRS was undertaken in an attempt to preserve hearing and minimize incidental cranial nerve injury. METHODS Thirty-three patients with vestibular schwannomas were treated with 2100 cGy in three fractions during a 24-hour period using conventional frame-based linear accelerator radiosurgery. The median tumor diameter was 20 mm (range, 7-42 mm). Baseline and follow-up evaluations included audiometry and contrast-enhanced magnetic resonance imaging. End points were tumor progression, preservation of serviceable hearing, and treatment-related complications. RESULTS Thirty-one patients (32 tumors) were assessable for tumor progression and treatment-related complications and 21 patients for preservation of serviceable hearing, with a median follow-up interval of 2 years (range, 0.5-4.0 yr). Tumor regression or stabilization was documented in 30 patients (97%) and tumor progression in 1 (3%). The patient with tumor progression remains asymptomatic and has not required surgical intervention. Five patients (16%) developed trigeminal nerve injury at a median of 6 months (range, 4-12 mo) after SRS; two of these patients had preexisting trigeminal neuropathy. One patient (3%) developed facial nerve injury (House-Brackmann Class 3) 7 months after SRS. Preservation of useful hearing (Gardner-Robertson Class 1-2) was 77% at 2 years. All patients with pretreatment Gardner-Robertson Class 1 to 2 hearing maintained serviceable (Class 1-3) hearing as of their last follow-up examination. CONCLUSION Three-fraction SRS with a conventional stereotactic frame is feasible and well tolerated in the treatment of acoustic neuroma. This study demonstrates a high rate of hearing preservation and few treatment-related complications among a relatively high-risk patient cohort (tumors >15 mm or neurofibromatosis Type 2). Longer follow-up will be required to assess the durability of tumor control.


International Journal of Radiation Oncology Biology Physics | 1996

High-dose therapy and autologous bone marrow transplantation for relapsed/refractory hodgkin's disease: The impact of involved field radiotherapy on patterns of failure and survival☆

Joseph C. Poen; Richard T. Hoppe; Sandra J. Horning

PURPOSE To assess the efficacy and toxicity of involved field (IF) radiotherapy in conjunction with high-dose therapy (HDT) and autologous bone marrow transplantation (ABMT) in relapsed or refractory Hodgkins disease (HD). METHODS AND MATERIALS Between 1987 and 1994, 100 consecutive patients with relapsed or refractory HD were treated with high-dose carmustine, etoposide, and cyclophosphamide or fractionated total-body irradiation, high-dose etoposide, and cyclophosphamide before ABMT. In addition, 24 patients received IF radiotherapy as planned cytoreductive (n = 18) or consolidative (n = 6) therapy immediately before or following ABMT. RESULTS With a median follow-up of 40 months (range: 18-88 months), 3-year actuarial rates of freedom from relapse (FFR), survival (S), and event-free survival (EFS) were 66%, 64%, and 57%, respectively. Thirty-three patients (33%) relapsed at a median of 8 months after ABMT. Only 2 of 33 relapses (6%) occurred beyond 18 months. By multivariate analyses, factors associated with recurrence were pleural disease (p = 0.02), multiple pulmonary nodules (p = 0.03), and a poor response to cytoreductive therapy (p = 0.001). A median IF radiotherapy dose of 30 Gy (range: 12.5-45 Gy) was given to 67 sites in the 24 patients. Local failure occurred within four irradiated sites (6%) in two patients (8%). In patients with relapse Stage I-III disease (n = 62), the use of IF radiotherapy was associated with an improved 3-year FFR (100% vs. 67%, p = 0.04) and a trend toward improved S (85 vs. 60%, p = 0.16). Among patients not previously irradiated (n = 39), IF radiotherapy was associated with an improved FFR (85 vs. 57%, p = 0.07) and S (93 vs. 55%, p = 0.02). Crude rates of treatment-related Grade 5 complications (including late events and second malignancies) were similar with or without IF radiotherapy (17 vs. 14%). CONCLUSIONS In conjunction with high-dose therapy and autologous bone marrow transplantation, IF radiotherapy is well tolerated, effectively controls local and regional disease, and may improve survival in selected patients with relapsed or refractory Hodgkins disease.


International Journal of Radiation Oncology Biology Physics | 2000

Adjuvant radiotherapy and concomitant 5-fluorouracil by protracted venous infusion for resected pancreatic cancer

Vivek K. Mehta; George A. Fisher; James M. Ford; Harry A. Oberhelman; Mark A. Vierra; Augusto J. Bastidas; Joseph C. Poen

PURPOSE To assess the toxicity and clinical benefit from adjuvant chemoradiotherapy consisting of protracted venous infusion 5-fluorouracil (5-FU) and concomitant radiotherapy in patients with resected pancreatic cancer. METHODS AND MATERIALS Between 1994 and 1999, 52 patients who underwent pancreaticoduodenectomy received adjuvant chemoradiotherapy. The tumor bed and regional nodes received a dose of 45 Gy in fractions of 1.8 Gy followed by boost to the tumor bed if the surgical margins were involved (total dose, 54 Gy). The patients also received concomitant 5-FU by protracted venous infusion (200-250 mg/m(2)/day, 7 days/week) during the entire radiotherapy course. RESULTS Fifty-two patients (30 men, 22 women) were enrolled and treated on this protocol. The median age was 63 years (range, 38-78 years), and the median Karnofsky Performance Status was 80 (range, 70-100). Thirty-five percent had involved surgical margins and 59% had involved lymph nodes. All patients completed therapy, and there were no Grade IV/V toxicities observed. With median follow-up of 24 months (range, 3-52 months) for surviving patients, the median survival is 32 months, and 2-year and 3-year survivals are 62%, and 39%, respectively. CONCLUSION Radiotherapy with concomitant 5-FU by protracted venous infusion as adjuvant treatment for resected pancreatic cancer is well tolerated. This approach allows for greater dose intensity with reduced toxicity. The median survival of this cohort of patients compares favorably with our earlier experience and other published series.


American Journal of Clinical Oncology | 1996

Postirradiation sarcoma of the gynecologic tract : a report of 13 cases and a discussion of the risk of radiation-induced gynecologic malignancies

Rufus J. Mark; Joseph C. Poen; Luu M. Tran; Yao S. Fu; James Heaps; Robert G. Parker

With improvement in survival after cancer treatment, it is becoming increasingly important to examine treatment-related morbidity and mortality. Sarcomas can develop within the irradiated field after radiation therapy (RT) for gynecologic malignancies. We undertook a study to assess the outcome after treatment of postirradiation sarcoma (PIS) of the gynecologic tract. In reviewing our data and the literature, we compare the absolute risk of PIS and other radiation-associated second malignant neoplasms (SMNs) with the mortality risk of surgery and general anesthesia. Between 1955 and 1987, 114 patients with uterine sarcomas were seen at the University of California, Los Angeles (UCLA), Medical Center. Thirteen had a prior history of RT. Conditions for which these patients received RT included choriocarcinoma (one), menorraghia (four), cervical cancer (six), and ovarian cancer (two). RT doses were known in six cases and ranged from 4,000 to 8,000 cGy. Latency time from RT to the development of PIS ranged from 3 to 30 years, with a median of 17 years. Twelve patients were treated with surgery or additional RT. Two patients remain alive 5 months and 57 months, respectively, following salvage therapy. Five-year disease-specific survival for all patients is 17%. From our data and a review of the literature, we estimate that the absolute risk of PIS with long-term follow-up ranges from 0.03 to 0.8%. Postirradiation sarcoma of the gynecologic tract is a relatively rate event associated with a poor prognosis. Mortality risks of radiation-associated SMN are similar to mortality risks of surgery and general anesthesia. Given the large number of patients with gynecologic malignancies who can be cured or palliated with RT, concern regarding radiation sarcomagenesis should not be a major factor influencing treatment decisions.


American Journal of Clinical Oncology | 2001

Protracted venous infusion 5-fluorouracil with concomitant radiotherapy compared with bolus 5-fluorouracil for unresectable pancreatic cancer.

Vivek K. Mehta; Joseph C. Poen; James M. Ford; Harry A. Oberhelman; Mark A. Vierra; Augusto J. Bastidas; George A. Fisher

Radiation therapy (RT) with concurrent 5-fluorouracil (5-FU) administered by protracted venous infusion (PVI) replaced our prior institutional protocol of RT with bolus administration of 5-FU as standard therapy for unresectable pancreatic cancer in 1994. In this article, we compare the treatment intensity, toxicity, and outcome for patients with unresectable pancreatic cancer treated on these sequential protocols. Fifty-four patients, 27 on each protocol, with biopsy-confirmed pancreatic cancer received chemoradiotherapy. The radiotherapy field included the gross tumor volume and regional lymph nodes to a dose of 45 Gy, followed by “boost” to the gross tumor volume to 54 Gy to 60 Gy. From 1987 to 1994, patients received concurrent 5-FU administered by bolus injection, at a dose of 500 mg/m2 on days 1 to 3 and days 29 to 31 of RT. After December 1994, 5-FU was administered by PVI (200–250 mg/m2) beginning on day 1 and continuing until the completion of RT. The chemotherapy treatment intensity was increased in the group receiving 5-FU by PVI, as evidenced by an increased average weekly and cumulative dose of 5-FU (p < 0.01). The radiotherapy treatment intensity was equivalent between the two groups. The incidence of objectively quantified toxicity was not statistically different between treatment groups. Overall survival remained poor in both treatment groups. With a median follow-up of 18 months (range: 3–30 months) for surviving patients, the 6-month, 1-year, and 2-year survivals for the PVI 5-FU-treated group versus the bolus 5-FU-treated group were 56% versus 52%, 34% versus 18%, and 22% versus 13%, respectively (p = 0.9). Radiotherapy with concomitant 5-FU by PVI results in a greater weekly and total dose of chemotherapy. The method of 5-FU administration (bolus versus PVI) did not change the RT treatment intensity, experienced toxicity, or overall survival.


Annals of Surgical Oncology | 1999

Chemoradiotherapy in the Management of Localized Tumors of the Pancreas

Joseph C. Poen; James M. Ford; John E. Niederhuber

In western countries, carcinoma of the pancreas remains the most lethal of the common malignancies. Even the favorable “organ-confined” tumors present a considerable challenge. The lack of anatomic barriers to local infiltration and the biological propensity for early lymphatic, perineural, and vascular invasion are nearly insurmountable obstacles to complete surgical eradication of this malignancy. Various combinations of chemotherapy and radiotherapy (RT) have been used with marginal but measurable success. Earlier trials conducted by the Gastrointestinal Tumor Study Group established roles for 5-fluorouracil chemotherapy and RT in the treatment of patients with resectable or locally advanced pancreatic cancer. More recently, computed tomography-guided conformal RT and a variety of intraoperative RT techniques have enabled more reliable sterilization of the local surgical field and escalation of doses to potentially curative levels (7000 cGy) for unresectable lesions. Chemotherapy dose intensification through the use of portable programmable pumps for protracted venous infusions and the development of active systemic agents in addition to 5-fluorouracil suggest that an effective combination chemotherapeutic regimen might soon be developed. This report reviews the current standards of practice and integrates recent developments to construct a modern algorithm for the use of chemoradiotherapy in the management of localized (nonmetastatic) pancreatic cancer. The likely directions of future investigations are also discussed.


Journal of Radiosurgery | 1999

Three-Fraction Stereotactic Radiosurgery for Treatment of Vestibular Schwannoma (Acoustic Neuroma) in Patients with Neurofibromatosis Type 2

Alexandra J. Golby; Joseph C. Poen; Kenneth M. Forster; David P. Martin; R John AdlerJr.

Neurofibromatosis type 2 (NF2) patients risk complete deafness from either bilateral vestibular schwannoma (VS) or its treatment. Both microsurgical resection and Stereotactic radiosurgery (SRS) have been associated with poorer rates of hearing preservation in patients with NF2 than in sporadic VS. In an attempt to maximize hearing preservation while maintaining good tumor control, we have conducted a prospective trial of three fraction SRS for the treatment of VS in patients with NF2. Eleven VS in 10 patients with NF2 were treated. Conventional frame-based Stereotactic localization was used. Mean maximal tumor diameter was 19.5 mm (range 11–28). A total dose of 21 Gy was administered in 7 Gy fractions with a mean interfraction interval of 12 hours. Patients were evaluated with neurologic examination, MRI, and audiometry. No patients were lost to follow-up. One patient died due to complications following surgical resection of a contralateral VS. Tumor (10–46 months posttreatment, mean 26 months) was stable or decreased in 9 of 10 tumors (90%). One patient experienced slight tumor enlargement at 27 months, which subsequently regressed. Actuarial rate of hearing preservation at 2 years was 67%. All patients (n = 5) with good pretreatment hearing (Gardner–Robertson grade 1 or 2) had preserved useful hearing (grade 1–3) at 1 year. Two patients (grade 3 and 4 hearing) lost all hearing within 24 hours of treatment; another patient with grade 3 hearing lost residual hearing over 6 months. One patient developed facial spasms. Three-fraction SRS for acoustic neuroma is well tolerated in patients with NF2 and is associated with a lower risk of hearing loss and other cranial neuropathy than single-fraction treatment. Continued follow-up will be necessary to evaluate long-term tumor control and hearing preservation.


International Journal of Radiation Oncology Biology Physics | 2004

Phase I study of stereotactic radiosurgery in patients with locally advanced pancreatic cancer.

Albert C. Koong; Quynh T. Le; Anthony Ho; Bryan Fong; George A. Fisher; Cheryl D. Cho; James M. Ford; Joseph C. Poen; Iris C. Gibbs; Vivek K. Mehta; Stephen T. Kee; Ward Trueblood; George P. Yang; J. Augusto Bastidas

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David P. Martin

Michigan State University

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