Bela Teleky

TP53 genotype but not p53 immunohistochemical result predicts response to preoperative short-term radiotherapy in rectal cancer.

ObjectiveTo evaluate and compare the predictive power of p53 gene analysis versus p53 immunohistochemical staining in terms of response to preoperative short-term radiotherapy using 25 Gy in operable rectal cancer. Summary Background DataRecent studies show that p53 may be a determinant of radiosensitivity being required for induction of apoptosis in case of radiation-induced DNA damage. MethodsPreirradiation biopsy samples of 64 patients with rectal carcinoma were analyzed. Genetic alterations of the p53 gene were detected by complete direct sequencing of exons 2 to 10. Expression of the nuclear phosphoprotein p53 was assessed by immunohistochemical staining. Results were correlated with histopathology of resected specimens and follow-up data, respectively. ResultsMutations of the p53 gene were present in 45% of tumors. Patients with a normal p53 gene had a significant survival advantage. Comparing pre- and postradiotherapy T category, a reduction was seen in patients with normal p53 genotype only. A mutant p53 genotype was highly specific in indicating stable disease concerning T category after irradiation. Protein overexpression was detected in 61%. Overexpression of the p53 protein was not related to survival or response. The concordance between immunohistochemistry and sequencing was only 0.51. ConclusionsThe authors show that downstaging after short-term radiation may occur but is seen in tumors with normal p53 gene only. Moreover, p53 genotype but not p53 immunohistochemistry is predictive for response to preoperative short-term radiotherapy and patient survival.

NeoGemOx: Gemcitabine and oxaliplatin as neoadjuvant treatment for locally advanced, nonmetastasized pancreatic cancer.

BACKGROUND Neoadjuvant chemotherapy can facilitate pancreatic resection in patients with initially unresectable pancreatic cancer (PC). We report the results of a phase II trial of gemcitabine-oxaliplatin neoadjuvant chemotherapy for patients with locally advanced, nonmetastatic PC. METHODS A prospective, phase II clinical trial using neoadjuvant chemotherapy, consisting of gemcitabine (900 mg/m(2)) and oxaliplatin (60 mg/m(2)) given as intravenous infusion once a week at day 1 of each treatment cycle (NeoGemOx protocol). Patients received 6-9 cycles of chemotherapy. Those patients with sufficient tumor regression subsequently underwent pancreatic resection and were followed postoperatively to assess long-term survival. RESULTS A total of 33 patients were eligible and were included in the intent-to-treat and evaluable population. On centralized review of the imaging studies, 18 patients had unresectable disease at inclusion, and 15 patients had borderline resectable PC. Eventually, 13 patients (39%) had a curative resection after neoadjuvant therapy. The R0 resection rate was 69%. Median overall survival of patients who underwent tumor resection was 22 months (95% confidence interval [CI], 14-30) compared with 12 months (95% CI, 9-15) for those without resection (P = .046). The median recurrence-free survival rate after resection was 10 months (95% CI, 4-17). CONCLUSION Neoadjuvant gemcitabine plus oxaliplatin is well tolerated and safe. Substantive tumor regression occurs in some patients with locally advanced PC treated with this neoadjuvant protocol, offering the potential for curative resection and improvement in overall survival. Additional studies involving the NeoGemOx protocol should be considered to further evaluate the safety and efficacy of this combination.

Detection of focal hepatic lesions: comparison of unenhanced and SHU 555 A-enhanced MR imaging versus biphasic helical CTAP.

The purpose of this study was to compare the diagnostic sensitivity of unenhanced magnetic resonance (MR) imaging, and MR imaging with a new superparamagnetic iron oxide (SPIO)‐enhanced contrast agent (SHU 555 A) with biphasic helical computed tomography during arterial portography (CTAP) in patients with focal liver lesions. Eighteen patients with a total of 91 (78 malignant, 13 benign) proven liver lesions underwent unenhanced short tau inversion recovery (STIR), T2‐weighted (T2‐w) TSE, and SHU 555 A‐enhanced T2‐w turbo spin‐echo (TSE) MR imaging and biphasic helical CTAP. The standard of reference was histopathologic analysis of resected specimens in 59 lesions, intraoperative ultrasound with biopsy in 20 lesions, and CT‐guided biopsy and follow‐up in 12 lesions. Diagnostic performance of the imaging modalities was compared quantitatively and qualitatively by assessing lesion involvement in liver segments. There were 68 lesions detected on unenhanced T2‐w TSE, which resulted in a sensitivity of 75%. With the STIR sequence, 76 lesions were detected, for a sensitivity of 84%, and with SHU 555 A‐enhanced MRI, 84 lesions were detected, for a sensitivity of 92%. CTAP detected 88 lesions, for a sensitivity of 97%. The accuracy for unenhanced T2‐w TSE was 98%, for STIR 99%, for enhanced‐MRI 100%, and for CTAP 95%. The specificity was 100% for SHU 555 A‐enhanced MRI and 95% for CTAP. SHU 555 A‐enhanced MRI was superior to nonenhanced MRI (P < 0.05) and equivalent to CTAP in terms of sensitivity. Due to the absence of false‐positive results on SHU 555 A‐enhanced MRI, the specificity and accuracy of enhanced MRI were higher than those of CTAP, but the difference was not statistically significant (P = 0.134). J. Magn. Reson. Imaging 2000;11:665–672.

Evaluation of perianal sepsis: Comparison of anal endosonography and magnetic resonance imaging

The purpose of this study was to compare prospectively the diagnostic yield of anal endosonography (AES) and magnetic resonance imaging (MRI) in the assessment of perianal fistulae and abscesses. There were 39 patients (14 men, 25 women; mean age, 40 years) who underwent AES, performed with a 10‐MHz rotating endoanal probe and MRI at 1.0 T (axial and coronal T2‐weighted turbo spin‐echo (TSE) and turbo‐STIR sequences). Fistulae were classified as subcutaneous, intersphincteric, transsphincteric, high (i.e., high extrasphincteric or suprasphincteric), rectovaginal, and horseshoe and were compared with the surgical findings in all patients. Overall, 58 fistulae (subcutaneous, N = 7; intersphincteric, N = 9; transsphincteric, N = 16; high, N = 17; rectovaginal, N = 5; and horseshoe, N = 4) were detected at surgery. MRI showed a sensitivity of 84% and AES of 60% (P < .05). False‐positive diagnoses were made in 6 patients (15%) with MRI and in 15 patients (26%) with AES, for a specificity of 68% and 21%, respectively (P < .05). Our findings show that MRI is superior to AES in the assessment of fistula‐in‐ano before major surgery. AES should be used only for orientation before minor procedures, such as incision or drainage of subcutaneous fistulae. J. Magn. Reson. Imaging 2001;14:254–260.

It is possible to omit postoperative irradiation in a highly selected group of elderly breast cancer patients

The purpose of this study was the evaluation of the necessity of routinely applied postoperative radiotherapy in a highly selected patient-group after breast conserving surgery. Between 1983 and May 1994, 356 women over 60 years of age with Stage I or II breast cancer were treated by quadrantectomy and axillary dissection followed by either adjuvant irradiation or no radiotherapy. We have analysed our data retrospectively to investigate whether irradiation has any benefit in elderly patients with respect to locoregional recurrence rates. After a median follow-up of 60 months the multivariate model revealed lymph node status (p=0.002) as highly significant with regard to local recurrence free survival. We were not able to identify a positive effect of adjuvant irradiation in patients with negative lymph nodes and positive receptor status: both patient groups with or without irradiation had similar locoregional recurrence rates of 3%. In a subgroup of patients who were lymph node negative, receptor positive, and received adjuvant tamoxifen therapy, the local recurrence rates were as low as 2% in both groups. Concerning these results it may be possible to avoid the morbidity and potential psychological side effects of radiotherapy in breast cancer patients over 60 years of age treated by breast conserving surgery (T1, N0, positive hormone receptor, adjuvant tamoxifen) without increasing risk of locoregional recurrence. These data have to be confirmed in a prospectively randomized fashion.

Endorectal Advancement Flaps in the Treatment of High Anal Fistula of Cryptoglandular Origin: Full-Thickness vs. Mucosal-Rectum Flaps

PurposeThe treatment of high anal fistula using endorectal advancement flaps represents an important technique to attain cure of fistulation and preserve anal continence. The creation of the advancement flap may comprise the rectal mucosa only or involve the full transection of the rectal wall. A comparison between full-thickness flaps and mucosal (partial-thickness) flaps was made to analyze the defining elements of successful fistula treatment: recurrence rates and anal continence.MethodsA retrospective review of 54 consecutive patients with high anal fistula of cryptoglandular origin was undertaken. Patient risk was categorized according to previous anal surgery. Continence was assessed according to the Vaizey score. Recurrence rates were recorded in a long-term, complete follow-up.ResultsThirty-four patients underwent surgery using a partial-thickness flap; in 20 patients the full-thickness flap was used. There were no major intraoperative or postoperative complications. Continence scores revealed significant incontinence in 11.1 percent of all patients. Full transection of the rectal wall for flap creation did not pose a threat to continence. Twenty-four percent of all patients suffered from a recurrence. Patients with four or more previous anal surgeries were at highest risk for failure. A single patient in the full-thickness flap group (5 percent) as opposed to 12 patients (35.3 percent) in the partial-thickness group suffered from recurrence.ConclusionThe comparison of partial-thickness to full-thickness endorectal advancement flaps suggests an improvement of recurrence rates without higher incontinence rates when a full mobilization of the rectal wall is performed.

Staining patterns of p53 immunohistochemistry and their biological significance in colorectal cancer

Immunohistochemistry (IHC) is a cheap and rapid method to detect p53 inactivation but the results are often discordant with gene mutation analysis. This study aimed to investigate whether there is a difference in the immunohistochemical staining patterns of p53‐positive cells on comparing tumours with inactivating gene mutations with those without. Tissues of 142 colorectal cancers were investigated for p53 inactivation simultaneously by IHC and gene analysis using SSCP of exons 4–9 and sequencing. In addition, tumours were investigated immunohistochemically for the expression of mdm‐2 protein, known to be transcriptionally transactivated by the wild‐type (wt) p53 gene. p53‐positive cells of tumours without detectable p53 gene mutations were microdissected using a PALM laser microscope system and subjected to p53 sequence analysis. Among the 142 cases of colorectal cancer (male/female=88/54; mean age 66a±11 years, range 24–90 years), 74% (n=105) of tumours were positive by p53 IHC and mutations in the p53 gene were found in 51% (73 patients). In 16% (12 patients) with mutations in the p53 gene, IHC for p53 was negative. In tumours with mutations in the p53 gene and positive p53 IHC, staining of all nuclei of the tumour was more frequently (57/61, 93%) found than in tumours without p53 gene mutations, where staining of scattered single cells was predominantly seen (29/44, 66%; p<0.0001). mdm‐2 positivity (n=33) showed only staining of scattered single cells, predominantly (24/33, 82%; p<0.0001) in tumours without gene mutations. Single cell microdissection followed by mutation analysis of scattered p53‐positive cells revealed no gene mutations. A scattered positive immunohistochemical reactivity of p53 in colorectal cancer cells might therefore represent a functionally active non‐mutated p53 gene and should not be considered as a marker of gene mutation and inactivation. Copyright

Stage-dependent Therapy of Rectal Carcinoid Tumors

Abstract. Although malignant behavior of rectal carcinoid tumors is rare, the risk of metastases and death does exist. Adaptation of therapy according to the estimated malignancy seems necessary. To develop a stage-dependent therapy, 31 patients with rectal carcinoid tumors measuring 5 to 50 mm in diameter were analyzed retrospectively. Malignancy was estimated according to tumor size, infiltration depth, and histopathology. There were 18 tumors within the mucosa and submucosa (T1), 7 tumors with muscularis propria invasion (T2), and carcinoid tumor penetrating the full rectal wall (T3) or spreading to surrounding tissue (T4) in 6 patients. Altogether 20 patients (65%) were treated with a minimally invasive intervention: endoscopic polypectomy (EP) in 12 and transanal excision (TE) in 8 patients. In 11 patients (35%) aggressive surgical procedures—anterior resection (AR) in 4 and abdominoperineal resection (APR) in 7—were performed. After a mean ± SD follow-up of 86.0 ± 61.3 months, tumor recurrence was not seen in any of the 20 patients with minimally invasive treatment, and all were still alive. No severe complications associated with surgical procedures were detected. In contrast, 5 of the 10 patients with advanced tumor stage died from their disease despite aggressive surgery (AR, APR). In conclusion, depending on tumor stage, treatment of rectal carcinoids includes EP, TE, or extended resection. Minimally invasive techniques are safe treatments for small to medium-size T1/T2 rectal carcinoids. Extended surgery cannot improve the overall survival of those with advanced tumors (T3/T4, N1, M1) but can be beneficial for preventing local complications.

Inhibition of P-glycoprotein-mediated vinblastine transport across HCT-8 intestinal carcinoma monolayers by verapamil, cyclosporine A and SDZ PSC 833 in dependence on extracellular pH

The ability of the multidrug resistance modifiers R- and R,S-verapamil (VPL), cyclosporine A (CsA) and its non-immunosuppressive derivative SDZ PSC 833 (PSC 833) to inhibit P-glycoprotein (P-gp)-mediated transepithelial flux of tritiated vinblastine was investigated using tight and highly resistant (R>1,400 Ω cm2) monolayer cultures of intestinal adenocarcinoma-derived HCT-8 cells grown on permeable tissue-culture inserts. Apical addition of these chemosensitisers inhibited drug flux (137 pmol h−1 cm−2; range, 133–142 pmol h−1 cm−2) in the basal to apical secretory direction at clinically relevant concentrations, with PSC 833 showing the highest activity, exhibiting inhibition at concentrations as low as 10 ng/ml (9 nM). Acidification of the modulator-containing apical compartment to an extracellular pH (pHo) of 6.8 had no influence on MDR reversal by CsA at 1 μg/ml (0.9 μM; flux inhibition, 52%) or by PSC 833 at 100 ng/ml (0.09 μM; flux inhibition, 60%), in contrast to R,S- and R-VPL, which showed decreased inhibition and caused less accumulation of vinblastine in HCT-8 cells under this condition (flux inhibition of 35% and 23%, respectively, at pHo 6.8 vs 50% and 43%, respectively, at pHo 7.5). P-gp-mediated rhdamine 123 efflux from dye-loaded single-cell suspensions of HCT-8 cells as measured by flow cytometry was not impeded at pHo 6.8 in comparison with pHo 7.5 in standard medium, but at low pHo the inhibitory activity of r-VPL (29% vs 60% rhodamine 123 efflux inhibition) was diminished significantly, again without a reduction in the effect of PSC 833 (rhodamine 123 flux inhibition, 75%). In conclusion, drug extrusion across polarised monolayers, which offer a relevant model for normal epithelia and tumour border areas, is inhibited by the apical presence of R,S- and R-VPL, CsA and PSC 833 at similar concentrations described for single-cell suspensions, resulting in increased (2.2- to 3.7-fold) intracellular drug accumulation. Functional apical P-gp expression, the absence of paracellular leakage and modulator-sensitive rhodamine 123 efflux in single HCT-8 cells indicate a P-gp-mediated transcellular efflux in HCT-8 monolayers. In addition to its high MDR-reversing capacity, the inhibitory activity of PSC 833 is not affected by acidic extracellular conditions, which reduce the VPL-induced drug retention significantly. As far as MDR contributes to the overall cellular drug resistance of solid tumours with hypoxic and acidic microenvironments, PSC 833 holds the greatest promise for clinical reversal of unresponsiveness to the respective group of chemotherapeutics.

Bacteroides fragilis toxin 2 damages human colonic mucosa in vitro

BACKGROUND Strains ofBacteroides fragilis producing a 20 kDa protein toxin (B fragilis toxin (BFT) or fragilysin) are associated with diarrhoea in animals and humans. Although in vitro results indicate that BFT damages intestinal epithelial cells in culture, the effects of BFT on native human colon are not known. AIMS To examine the electrophysiological and morphological effects of purified BFT-2 on human colonic mucosa in vitro. METHODS For resistance (R) measurements, colonic mucosa mounted in Ussing chambers was exposed to luminal or serosal BFT-2 (1.25–10 nM) and after four hours morphological damage was measured on haematoxylin and eosin stained sections using morphometry. F actin distribution was assessed using confocal microscopy. RESULTS Serosal BFT-2 for four hours was four-, two-, seven-, and threefold more potent than luminal BFT-2 in decreasing resistance, increasing epithelial3H-mannitol permeability, and damaging crypt and surface colonocytes, respectively (p<0.05). Confocal microscopy showed reduced colonocyte F actin staining intensity after exposure to BFT-2. CONCLUSIONS BFT-2 increases human colonic permeability and damages human colonic epithelial cells in vitro. These effects may be important in the development of diarrhoea and intestinal inflammation caused by B fragilis in vivo.