Biomedical subjects

George J Chang

Publications and source records attributed to George J Chang.

10 recordsLinked to original sources

PubMed2006

Results of surgical salvage after failed chemoradiation therapy for epidermoid carcinoma of the anal canal.

BACKGROUND: The standard treatment for epidermoid carcinoma of the anal canal consists of combined radiation and chemotherapy. For patients who present with persistent or locally recurrent disease, salvage abdominoperineal resection is the treatment of choice. The purpose of this study is to review our experience with salvage surgery in this group of patients. METHODS: From 1990-2002, 31 patients underwent radical salvage surgery with curative intent after failure of initial sphincter-conserving therapy, and the medical records of these patients were retrospectively reviewed. Clinicopathologic variables were determined and comparisons performed with the Cox proportional hazards model. Survival was calculated by the Kaplan-Meier method. RESULTS: Eleven patients underwent radical salvage surgery for persistent disease and 20 patients for recurrent disease. The median follow-up time was 29 months. The actuarial 5-year overall survival was 64%. Twelve patients developed recurrent disease after radical salvage surgery. Patients who received an initial radiation dose of less than 55 Gy had a significantly worse survival than those who received at least 55 Gy as part of their initial treatment (5-year overall survival 37.5% vs. 75%; age-adjusted hazard ratio 8.2 [95% CI: 1.1-59.8], P = .037). The presence of positive lymph nodes at presentation also adversely affected survival (P < .05). Factors that were not found to have an impact on survival included the presence of persistent versus recurrent disease, tumor (T) stage, and margin status of resection. CONCLUSIONS: Long-term survival following salvage surgery for persistent or locally recurrent epidermoid carcinoma of the anal canal can be achieved in the majority of patients. However, patients who initially present with node-positive disease and patients who receive a radiation dose of less than 55 Gy as part of their initial chemoradiation therapy regimen have a worse prognosis after radical salvage surgery.

Adult↗

PubMed2006

Phase II study of capecitabine (Xeloda) and concomitant boost radiotherapy in patients with locally advanced rectal cancer.

PURPOSE: The aim of this study was to determine the efficacy of capecitabine (Xeloda), an oral fluoropyrimidine, as a radiosensitizer in the neoadjuvant treatment of locally advanced rectal cancer (LARC). METHODS AND MATERIALS: We conducted a phase II study of capecitabine (825 mg/m2 orally, twice daily continuous) with radiotherapy (52.5 Gy/30 fractions to the primary tumor and perirectal nodes) in 54 patients with LARC (node-negative > or = T3 or any node-positive tumor) staged by endoscopic ultrasound (EUS). The primary endpoint was pathologic response rate; secondary endpoints included toxicity profiles and survival parameters. RESULTS: Of the 54 patients (median age, 56.7 years; range, 21.3-78.7 years; male:female ratio, 1.7; Eastern Cooperative Oncology Group performance status 0-1: 100%), 51 patients (94%) had T3N0 or T3N1 disease by EUS. Surgery was not performed in 3 patients; 2 of these patients had metastatic disease, and the third patient refused after a complete clinical response. Of the 51 patients evaluable for pathologic response, 9 patients (18%) achieved complete response, and 12 patients (24%) had microscopic residual disease (< 10% viable cells). In addition, 26 patients of all 54 patients (51%) achieved T-downstaging, and 15 patients of 29 patients (52%) achieved N-downstaging. Grade 3/4 toxicities were radiation dermatitis (9%) and diarrhea (2%). Sphincter preservation rate for tumor < or = 5 cm from the anal verge was 67% (18/27). CONCLUSION: This regimen of radiotherapy plus capecitabine is well tolerated and is more convenient than protracted venous infusion of 5-FU. The pathologic response rate is comparable to our previous experience using protracted venous infusion 5-FU for LARC.

Adult↗

PubMed2006

Preoperative chemoradiotherapy with capecitabine versus protracted infusion 5-fluorouracil for rectal cancer: a matched-pair analysis.

PURPOSE: To retrospectively compare the acute toxicity, pathologic response, relapse rates, and survival in rectal cancer patients treated with preoperative radiotherapy (RT) and either concurrent capecitabine or concurrent protracted infusion 5-fluorouracil (5-FU). METHODS: Between June 2001 and February 2004, 89 patients with nonmetastatic rectal adenocarcinoma were treated with preoperative RT and concurrent capecitabine, followed by mesorectal excision. These patients were individually matched by clinical T and N stage (as determined by endoscopic ultrasound and CT scans) with 89 control patients treated with preoperative RT and concurrent protracted infusion 5-FU between September 1997 and August 2002. RESULTS: In each group, 5 patients (6%) had Grade 3-4 toxicity during chemoradiotherapy. The pathologic complete response rate was 21% with capecitabine and 12% with protracted infusion 5-FU (p = 0.19). Of the 89 patients in the capecitabine group and 89 in the 5-FU group, 46 (52%) and 55 (62%), respectively, had downstaging of the T stage after chemoradiotherapy (p = 0.20). The estimated 3-year local control (p = 0.15), distant control (p = 0.86), and overall survival (p = 0.12) rate was 94.4%, 86.3%, and 89.8% for patients treated with capecitabine and 98.6%, 86.6%, and 96.4% for patients treated with protracted infusion 5-FU, respectively. CONCLUSION: Preoperative concurrent capecitabine and concurrent protracted infusion 5-FU were both well tolerated, with similar, low rates of Grade 3-4 acute toxicity. No significant differences were seen in the pathologic response, local and distant recurrence, or overall survival among patients treated with preoperative RT and concurrent capecitabine compared with those treated with RT and concurrent protracted infusion 5-FU.

Adult↗

PubMed2006

Laparoscopic treatment of colorectal neoplasia.

A recent major advance in the surgical treatment of colorectal cancer has been the introduction of laparoscopic surgery. Laparoscopic colectomy is associated with decreased postoperative pain, faster ileus resolution, shorter hospital stay, improved cosmesis, and decreased morbidity when compared with open colectomy. However, early reports of high rates of laparoscopic wound metastases gave rise to questions regarding the adequacy of the laparoscopic technique for curative resection of malignancies. These concerns over oncologic outcomes are addressed by several single and multi-institutional randomized trials in the United States and throughout the world that have compared laparoscopic-assisted colectomy with conventional open colectomy. These studies have established both the short- and long-term safety and oncologic efficacy of laparoscopic colectomy for cancer. To ensure successful outcomes, surgeons performing laparoscopic colectomy should be adequately experienced. Limitations include the technical requirements of advanced laparoscopic skills and training, increased operative time, and equipment costs. Despite these limitations, patient recovery benefits may offset the increased operative costs and result in improved outcome overall.

Journal Article↗

PubMed2006

Surgical implications of colorectal cancer genetics.

The applications of genetics in colorectal cancer are not limited to identifying germ-line mutations in genetically predisposed individuals. Reports on the use of molecular genetic markers as prognostic factors and for assessing the response to therapy are common in the literature. As the primary caregiver in the majority of these cases, the surgeon needs a basic knowledge of colorectal genetics and their implications to the patient and the patient's family. This article discusses a practical approach for some of the issues likely to be encountered by the surgeon.

Adenomatous Polyposis Coli↗

PubMed2006

Clinical and pathologic predictors of locoregional recurrence, distant metastasis, and overall survival in patients treated with chemoradiation and mesorectal excision for rectal cancer.

OBJECTIVES: To identify predictive factors for locoregional recurrence (LR), distant metastasis (DM), and overall survival (OS) in patients treated with chemoradiation and surgery for rectal cancer. METHODS: Between 1989 and 2001, 470 patients with rectal cancer were treated with preoperative (89%) or postoperative (11%) chemoradiation and mesorectal excision. Median radiation dose was 45 Gy; 97% received concurrent infusional 5-fluorouracil, and 65% received adjuvant chemotherapy. Median follow-up interval was 5.7 years. RESULTS: The 5-year rates of freedom from LR, freedom from DM, and OS were 90%, 79%, and 80%, respectively. On univariate analysis, significant predictors of LR were female sex, clinical T stage, pathologic T and N stages, and positive radial margin. Significant univariate predictors of DM were circumferential extent of tumor, tumor immobility, lymphovascular invasion, perineural involvement, and pathologic T and N stages. Significant univariate predictors of lower OS were age, circumferential extent of tumor, shorter distance from anal verge, tumor size, tumor immobility, anal canal involvement, lymphovascular invasion, perineural involvement, positive radial margin, and pathologic T and N stages. On Cox multivariate analysis, female sex and pathologic T and N stages independently predicted for LR; pathologic T and N stages independently predicted for DM; and age, circumferential extent of tumor, positive radial margin, and pathologic T and N stages independently predicted for lower OS. CONCLUSIONS: Pathologic T and N stages significantly predicted for all 3 end points (LR, DM and OS) on multivariate analysis. Investigations of more aggressive adjuvant chemotherapy appear warranted for pathologic stage T3/T4 or N1/2 rectal cancer.

Adult↗

PubMed2005

Laparoscopic colectomy.

Minimally invasive surgical techniques are preferred for a variety of surgical disorders and result in improved outcomes. Laparoscopic colectomy is associated with decreased postoperative pain, faster ileus resolution, shorter hospitalization, and improved cosmesis when compared with open colectomy. The laparoscopic technique is now often preferred for benign disease, but concerns over oncologic adequacy have limited its availability for cancer. The Clinical Outcomes of Surgical Therapy randomized trial of laparoscopic versus open colectomy for cancer recently validated the efficacy of laparoscopy for colon cancer. Limitations include the technical requirements of advanced laparoscopic skills and training, increased operative time, and equipment costs. Surgeons performing laparoscopic colectomy should be adequately experienced and certified to ensure successful outcomes. Despite these limitations, patient recovery benefits may offset the increased operative costs and result in improved cost-effectiveness overall.

Clinical Trials as Topic↗

PubMed2003

Expanding the donor pool: can the Spanish model work in the United States?

Since the creation of the Organizacion Nacional de Trasplantes (ONT) in 1989, the organ donation rate in Spain has doubled. Although often attributed to improved donor recruitment efforts, this increase may also represent higher utilization of marginal donors. Therefore, age-related donor recruitment in Spain and the US was evaluated. Data from the ONT, the US Scientific Registry of Transplant Recipients (SRTR), the US Census Bureau, and the Tempus databank of Spain's Instituto Nacional de Estadistica (INE) were analyzed. Between 1989 and 1999, the number of donors in Spain increased from 14.3 to 33.7 per million population (pmp; 136% increase) compared with an increase in the US from 16.2 to 21.5 donors pmp (33%). The largest difference between Spain and the US in the increased number of donors was in the 45-year-old group, representing 30.3% of donors in Spain in 1999 (44 donors pmp). If the US increased its older donor rates to match Spain's, an incremental 1235 donors per year would be realized. The high Spanish organ donation rates are largely attributable to increased use of older donors. Utilizing similar proportions of older donors in the US would increase the donor pool by almost 40%.

Adolescent↗

PubMed2002

Surgical treatment of high-grade anal squamous intraepithelial lesions: a prospective study.

PURPOSE: The prevalence of anal squamous intraepithelial lesions is high among human immunodeficiency virus-positive homosexual males and, to a lesser extent, among human immunodeficiency virus-negative homosexual males. Furthermore, the incidence of high-grade squamous intraepithelial lesions, the putative precursor lesion to invasive cancer, is also high. We report the first prospective study of high-resolution anoscopy-directed surgical treatment of high-grade squamous intraepithelial lesions. METHODS: A prospective study of patients undergoing surgical treatment of high-grade squamous intraepithelial lesions (excision/cauterization of lesions visualized with high-resolution anoscopy) was performed. Follow-up anoscopy with biopsy and Papanicolaou smear was performed every three to six months. RESULTS: Patients diagnosed with high-grade squamous intraepithelial lesions during the course of their participation in a prospective cohort study of anal squamous intraepithelial lesions were identified. From this group, 37 patients who were treated surgically between 1995 and 1999 were studied. Of these, 29 had tested positive for human immunodeficiency virus and 8 were negative for the virus. Mean patient age was 45 +/- 8 years. Mean duration of follow-up was 32.3 +/- 20.6 months in the human immunodeficiency virus-negative group and 28.6 +/- 12.9 months in the human immunodeficiency virus-positive group. No human immunodeficiency virus-negative patient developed recurrent high-grade squamous intraepithelial lesions. Twenty-three of 29 human immunodeficiency virus-positive patients had persistent or recurrent high-grade squamous intraepithelial lesions (P = 0.003; mean time to recurrence, 12 months). Six patients underwent reoperation for high-grade squamous intraepithelial lesions (4 recurred by 6 months). No patients developed incontinence, stenosis, postoperative infection, or significant bleeding after surgical treatment. CONCLUSIONS: Surgical intervention directed by high-resolution anoscopy is safe and eliminates high-grade squamous intraepithelial lesions in human immunodeficiency virus-negative patients. The high persistence or recurrence rate in human immunodeficiency virus-positive patients suggests that multiple staged procedures and continued surveillance may be necessary.

Adult↗

PubMed2002

Targeted gene therapy with CD40Ig to induce long-term acceptance of liver allografts.

BACKGROUND: The purpose of this study was to modulate the immune response of rat liver transplant recipients by adenovirus-mediated gene transfer of CD40Ig, a secretable fusion protein designed to block the CD40-CD154 T-cell costimulation pathway. METHODS: CD40Ig complementary DNA was created by joining the reverse transcriptase-polymerase chain reaction complementary DNA products for the extracellular domain of murine CD40 to the Fc portion of murine IgG2a. AdCD40Ig and AdSIg (IgG2a-Fc control) recombinant adenoviruses were used to transduce donor liver grafts before nonarterialized orthotopic rat liver transplantation. Donor specific unresponsiveness was examined with skin transplants. RESULTS: All rats (n = 6) that received liver allografts transduced with AdCD40Ig survived >100 days with normal liver histology. Serum levels of CD40Ig at 10, 30, 60, and 100 days after transplantation ranged from 100 to 500, 100 to 250, 5 to 40, and 2 to 10 microg/mL, respectively. Mean survival of rats (n = 4) that received liver allografts transduced with AdSIg control adenovirus was 9.25 +/- 2.9 days. Long-term survivors were rechallenged with skin grafts 100 days after liver transplantations. Survival was 72, >100 (x4) days for donor specific allogeneic skin grafts and 14, 14, 18, 19, and 21 days for third-party allogeneic skin grafts. CONCLUSIONS: Adenovirus-mediated gene transfer of CD40Ig into cold-preserved liver allografts before transplantation results in high levels of transgene expression with resultant long-term survival of hepatic allografts and donor specific unresponsiveness.

Adenoviridae↗