Cervix cancer regression measured using weekly MR imaging during fractionated radiotherapy: Radiobiologic modeling and correlation with tumor hypoxia

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Background: To utilize cervix cancer volumetry, as measured with MR imaging during definitive chemoirradiation (RT-CT), to derive radiobiological parameters using a mathematical model of tumor regression, and compare them to pre-treatment measurements of tumor hypoxia. Methods: Twenty-eight patients receiving RT-CT for cervix cancer underwent weekly magnetic resonance imaging (MRI) scans. Tumor volume was assessed on each of these scans and the rate of regression plotted. A mathematical model of tumor regression was formulated to simulate the relationship between three independent radiobiological parameters, 1) surviving fraction of cells after 2 Gy, SF2, 2) the cell clearance constant Tc, and 3) the cellular proliferation constant Tp. Non-linear regression analysis was applied to fit the MR-derived tumor volumes to the mathematical model and to derive SF2 and Tc values for each patient. These were compared to pre-treatment hypoxia measurements. Results: Initial tumor volume ranged between 8 and 209 cm3. Relative reduction in volume during treatment was 0.02 to 0.79. Simulations using representative values of the independent biologic variables derived from the literature showed SF2 and Tc to strongly influence the shape of the volume response curves. Non-linear regression analysis yielded a median SF2 of 0.71 and median Tc of 10 days. Radioresistant tumors (SF2 >0.71) were significantly more hypoxic at diagnosis (p=0.02). Conclusion: Based on serial MR imaging during treatment, a marked variation in cervix tumor regression is seen from patient to patient. Through our radiobiological model, tumors can be classified as radioresistant or radiosensitive, which correlates with hypoxia

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No significant financial relationships to disclose.

Effects of prior endoluminal gastroplication on subsequent laparoscopic Nissen fundoplication

BACKGROUND

The long-term results of endoluminal gastroplication (ELGP) for gastroesophageal reflux disease (GERD) are still under investigation. Laparoscopic Nissen fundoplication (LNF) has unquestionable results in the treatment of GERD and, therefore, it would be unfortunate to compromise this treatment option by performing alternative therapies such as ELGP.

METHODS

Six patients underwent ELGP for the treatment of GERD symptoms. After symptoms returned, these patients elected to have a LNF.

RESULTS

There was no sign of periesophagitis or intraperitoneal adhesion formation found at hiatal dissection that hindered or complicated the LNF procedure. Recent follow-up has shown that the patient's GERD symptom scores have decreased, as expected after a de novo LNF.

CONCLUSION

ELGP does not alter the surgical dissection or results of a subsequent LNF.

Laparoscopic re-operation for failed Heller myotomy

Laparoscopic Heller myotomy for achalasia has a 10-20% failure rate and may require re-operation to control persistent or recurrent symptoms. We report follow-up of 15 patients who underwent laparoscopic re-operation for failed Heller myotomy. Between 1993 and 2004, 15 patients underwent laparoscopic re-operation for failed Heller myotomy at our center. The mean duration between procedures was 23 months. Follow-up was completed at a mean duration of 30 months in 14 patients (93%) via a telephone questionnaire. Our overall failure rate for primary surgery (n = 106) was 5.6%. The mechanisms of failure were incomplete myotomy (33%), myotomy fibrosis (27%), fundoplication disruption (13%), too tight fundoplication (7%) and a combination of myotomy fibrosis and incomplete myotomy (20%). Significant symptom improvement was observed with postoperative symptom resolution seen in 71% of patients with dysphagia, 89% for regurgitation, 58% for heartburn and 40% for chest pain. Fifty percent reported excellent results and 79% would recommend the procedure to a friend. Subsequent dilations were performed in four patients (29%). Two patients required conversion to open surgery (13%). Three patients (20%) failed the re-operation and required further revisional surgery. Complications included intraoperative perforation in three (none of which resulted in postoperative morbidity) and a pneumothorax in one patient. Prior endoscopic therapies (pneumatic dilation or Botulinum toxin) were not associated with poor results. Laparoscopic re-operation for failed Heller myotomy is feasible and results are encouraging.

Technique and follow-up of minimally invasive Heller myotomy for achalasia

BACKGROUND

Laparoscopic Heller myotomy has been proven effective. Reliable predictive factors for outcome and the true benefit of the da Vinci robotic system, however, remain unknown.

METHODS

Seventy patients underwent laparoscopic Heller myotomy. The number of intraoperative perforations and the symptom-predictive value of postoperative esophagogram width measurement at the gastroesophageal junction were analyzed.

RESULTS

The overall complication rate was 11%. Four patients experienced intraoperative perforation during the laparoscopic technique. No perforations were experienced with the da Vinci robotic system (n = 19). Of the total, 82% of patients had resolution of dysphagia, 91% of regurgitation, 91% of heartburn and 82% of chest pain. Immediate postoperative esophagogram gastroesophageal junction width demonstrated a positive predictive trend from 0 to 10 mm for dysphagia.

CONCLUSION

Laparoscopic Heller myotomy is an effective treatment for achalasia. Immediate postoperative esophagogram gastroesophageal junction width measurement as a predictor for symptom resolution requires further study.

Recombinant polymers for cancer gene therapy: A minireview

A major challenge for successful cancer gene therapy is the development of safe and effective gene delivery vectors. Gene delivery vectors can be viral or nonviral. Among nonviral vectors various polymeric vectors have shown potential in gene delivery. However, much work needs to be done in order to correlate polymer structure with gene release at the target site and transfection efficiency. This article is a brief introduction into cancer gene therapy, barriers and methods for gene transfer with emphasis on the applications of recombinant polymers for cancer gene therapy.

Pseudocyst rupture into the portal vein diagnosed with MRI

We report on the first documented case of rupture of a pancreatic pseudocyst into the portal vein diagnosed with MRI.

Alpha-2-globin gene polyadenylation (AATAAA-->AATAAG) mutation in hemoglobin H disease among Kuwaitis

OBJECTIVES

In the Arabian Gulf region, hemoglobin (Hb) H disease usually results from homozygosity or compound heterozygosity involving the alpha2-globin gene polyadenylation (poly A) signal (AATAAA-->AATAAG) mutation (alpha(T)alpha). Here we document the clinical and hemato logical characteristics of children with Hb H disease being followed in Kuwait.

SUBJECTS AND METHODS

Twenty-four patients (0.5-12 years old, mean 4.7 +/- 3.5 years) with persistent microcytic, hypochromic anemia (and normal iron status as well as normal Hb A2 levels) were referred to the pediatric hematology clinic for further investigations. They were all screened for the alpha+-thalassemia (alpha+-thal; -3.7 kb) deletion using a standard PCR method. They were also screened for the alpha2-globin gene alpha(T)alpha allele and the 5nt deletion (-alpha5nt) in the first intervening sequence, which are common alpha-thal alleles in this population. They were followed up for periods ranging from 2 to 8 years.

RESULTS

Of the 24 patients, 4 (16.7%) also had sickle cell trait (Hb-AS), while 7 (29.2%) were glucose-6-phosphate dehydrogenase deficient. Only 1 patient had significant hepatosplenomegaly and 1 developed gallstones. While none was on chronic transfusion therapy, 8 (33.3%) had been transfused at least once and, in 3 instances, this was secondary to parvovirus B19 +ve aplastic crisis. The alpha-globin genotype was successfully determined in almost all patients. The results showed that 17 (70.8%) patients were homozygous for the poly A mutation (alpha(T)alpha/alpha(T)alpha), 6 (25.0%) were compound heterozygotes for this and the alpha+-thal (-3.7 kb) deletion (-alpha/alpha(T)alpha) and 1 (4.2%) was undetermined. There were no significant differences in the phenotypes of the 2 genotypes and their hematological features were identical.

CONCLUSIONS

Hb H disease involving the poly A mutation is a mild thal intermedia phenotype among Kuwaitis. There are no serious complications and there is no need for regular blood transfusion.