Oncologic outcomes following radical resection with intraoperative electron radiation therapy in patients with recurrent colorectal cancer

508

Background: Of the 40,000 rectal cancer patients treated annually, up to 15% will experience a local recurrence (LR). Resection only series for LR report 30–60% positive margin rates. For this reason our institution utilizes intra-operative electron radiation therapy (IOERT) in patients undergoing resection of locally advanced rectal cancer recurrences (LA-RRC). The purpose of this study was to evaluate the oncologic outcomes of patients treated for a LA-RRC with resection and IOERT

Methods: Under IRB approval a prospective database of patients with LA-RRC undergoing resection and IOERT from April 2001 to January 2010 was analyzed. Demographic, clinical, and pathologic variables were collected. The Kaplan-Meier method estimated 5-year overall survival (OS) and Fisher's Exact test's explored associations for developing a LR.

Results: Fifty patients (32 male, mean age 58 ± 11) underwent resection and IOERT (median dose 1500 cGy, energy 9 MeV). Primary procedures included pelvic exenteration (n = 17), APR (n = 10), LAR (n = 7), isolated pelvic/retroperitoneal tumor (n = 7), para-aortic lymphadenectomy (n = 7), and partial colectomy (n = 2). 56% (n = 28) required multi-visceral resections including partial/total cystectomy (n = 14), small bowel resection (n = 10), vaginectomy (n = 6), hysterectomy (n = 3), oophorectomy (n = 3), nephrectomy (n = 2), and other (n = 4). 34 pelvic sidewall resections and 12 partial sacrectomies were required. Margins were R0 in 37 (74%) and R1 in 13 (26%). Median LOS was 10 days and there were no peri-operative deaths. Five-year OS was 32% with a 19-month follow-up of survivors. 32% (n = 16) developed a pelvic LR, of which 2 were isolated and 14 were in the setting of distant metastasis. No difference was noted in OS (p = 0.5) or LR (p = 0.3) in patients with R0 vs. R1 resections. Initial T (p = 0.1), N (p = 0.2), and stage (p = 0.7) were not found to be associated with LR.

Conclusions: This study reveals that resection combined with IOERT provides good local control and reasonable long-term survival in patients with LA-RRC. The similar OS and LR following an R0 and R1 resections could be interpreted as a measure of the beneficial effect of IOERT on microscopic disease.

No significant financial relationships to disclose.

GCC expression in lymph nodes (LNs) as a significant determinant of recurrence in stage II colon cancer (CC) patients (pts)

369

Background: A multi-center prospectively specified retrospective study Validating Indicators to Associate Recurrence (VITAR) is assessing the relationship between guanylyl cyclase C (GCC) gene expression in formalin fixed LNs and recurrence risk in stage II CC pts not treated with adjuvant chemotherapy. Here we report the preplanned initial analysis performed with 241 pts.

Methods: GCC mRNA was quantified by RT-qPCR using FFPE LNs tissues from untreated stage II CC pts diagnosed from 1999-2006 with at least 10 LN examined blinded to clinical outcomes. Cox regression models examined the relationship between GCC nodal status and the prespecified primary endpoint of recurrence risk.

Results: Twenty-ninepts (12%) had a disease recurrence or cancer death, median follow-up was 60 months and median LNs examined was 15. The ratio of the number of GCC+ LNs over the total number of informative LNs (LNR) significantly predicted higher recurrence risk for 84 pts classified as high risk (HR, 2.38; p=0.02). The estimated 5-yr recurrence rates were 10% and 27% for the low and high risk group, respectively. After adjusting for age, T stage, number of LNs assessed, and MMR status, the significant association remained (HR, 2.61; 95% CI, 1.17-5.83; p=0.02). In a subset of 181 pts with negative margin, T3 tumor only and ≥12 LN examined, the GCC LNR had a HR for recurrence of 5.06 (95% CI 1.61-15.91, p=0.003), translating into 5-yr recurrence rates of 4% among low risk pts and 27% for the high-risk group.

Conclusions: Our results suggest that GCC expression in LNs is a significant determinant of recurrence in appropriately staged CC pts not treated with adjuvant chemotherapy. The validation component of the study is ongoing.

[Table: see text]

[Table: see text]

Utility of routine PET/CT and MRI staging in patients with sentinel lymph node positive melanoma

9071

Background: The utility of routine radiographic staging in sentinel lymph node (SLN) positive stage III melanoma is unclear. Although body computed tomography (CT) has proven unlikely to identify occult metastasis at the time of diagnosis, there is some suggestion that whole body positron emission tomography combined with computed tomography (PET/CT) may be more sensitive in the detection of clinically unsuspected metastatic melanoma. We evaluated the ability of routine PET/CT and brain MRI to detect occult metastatic disease at the time of diagnosis in patients with SLN positive stage III melanoma. Methods: All clinically node- negative patients with cutaneous melanoma and a positive SLN who completed staging with PET/CT from 2003 through 2008 were identified from a prospective, IRB-approved, single-institution database. Data were analyzed to determine the positive (PPV) and negative (NPV) predictive values of PET/CT in detecting occult metastatic disease. Results: 72 patients had a positive SLN and were staged with PET/CT and 61 with brain MRI. There were 41 men and 31 women. Median age was 55 years. Median Breslow depth was 2.50 mm. 5 patients were T1, 25 T2, 22 T3, and 20 T4. 46 % were ulcerated. MRI was negative in all 61 patients. PET/CT was interpreted as suspicious for metastasis in 8 patients (11%) and negative in 64 (92%). 6 (8%) of the suspicious PET/CT scans were subsequently proven to be negative for malignancy and 1 (1.4%) proven to be an incidental thyroid cancer. Only 1 patient (1.4%) was found to have metastatic melanoma, an in transit metastasis that was previously unrecognized. PPV was 13% and NPV 100% for PET/CT. No patients were found to have occult distant metastases by either brain MRI or PET/CT. Conclusions: Patients with SLN positive stage III melanoma are unlikely to have occult metastatic disease detected by PET/CT or brain MRI and should not have further therapy delayed to obtain imaging. These findings are consistent with prior reports of body CT alone and question the utility of routine staging with current imaging modalities in patients with SLN positive melanoma. Future research should be directed toward improved imaging techniques in order to detect early micrometastatic melanoma.

No significant financial relationships to disclose.

Diabetes mellitus affects response to neoadjuvant chemoradiotherapy in the management of rectal cancer

INTRODUCTION

Although diabetic patients with rectal cancer have poorer outcomes than their nondiabetic counterparts, few studies have looked at diabetics' response to therapy as an explanation for this disparity. This study compares the neoadjuvant chemoradiotherapy (CRT) response in diabetic and nondiabetic patients with locally advanced rectal cancers.

METHODS

This is a single-institution, retrospective review of rectal cancer patients who received CRT followed by resection from 1995 to 2006. Pretreatment tumor-node-metastasis (TNM) staging was determined using endorectal ultrasound, computed tomography (CT) scan, and magnetic resonance imaging (MRI); post-treatment staging was determined by pathological review.

RESULTS

110 patients were included; seventeen had diabetes and 93 were nondiabetics. Pretreatment staging was similar in both groups. Sixteen of the diabetics (94%) completed CRT compared to 92% (86/93) of the nondiabetics. Tumor downstaging rates were similar in the two groups (53% in diabetics, 52% in nondiabetics). Nondiabetic patients had a higher rate of nodal downstaging although not statistically significant (67% versus 27%, P = 0.80). While none of the diabetics patients achieved a pathologic complete response (pCR), 23% (21/93) of the nondiabetics did (P = 0.039). Local progression rates were higher in the diabetic group (24% versus 5%, P = 0.046).

CONCLUSION

Our study shows that neoadjuvant chemoradiotherapy in rectal cancer is less effective in diabetic patients than in nondiabetics. While minimal differences are found in the rate of downstaging, the rate of achieving a complete pathologic response was significantly higher in nondiabetic patients, and in fact was not seen in any of our diabetic patients. This may explain the poorer outcomes seen in diabetic patients with rectal cancer.

Ratio of metastatic to examined lymph nodes is a powerful predictor of overall survival in rectal cancer: An analysis of Intergroup 0114

4006

Background: Lymph node (LN) metastasis is associated with decreased survival in rectal cancer. It has been suggested that at least 14 LN be evaluated for adequate staging. However, a large percentage of patients have fewer than the recommended number of LN examined. We hypothesized that LN ratio would be predictive of overall survival in rectal cancer. Methods: Data was analyzed from Intergroup 0114, a mature trial of postoperative adjuvant chemotherapy and radiation in T3/4 and/or LN positive rectal cancer. Survival was the same for all arms allowing the entire group to be considered as one. The primary endpoint evaluated was overall survival. A proportional hazards model was used to determine the relative prognostic impact of LN ratio compared to number of LN examined, number of positive LN, number of negative LN and AJCC nodal stage. LN ratio was defined as the number of positive LN divided by the total number of LN examined. Four groups were analyzed based on proportion of positive LN: =0.25, >0.25–0.50, >0.50–0.75 and >0.75. Results: 1,648 patients were evaluable. There were 251 T1/2, 1,251 T3 and 146 T4 tumors. 513 patients were N0, 743 N1 and 392 N2. Median number of LN was 9. LN ratio was predictive of 5-year overall survival with rates of 0.71, 0.56, 0.50 and 0.43 respectively when analyzed by quartile (p<0.0001). LN ratio remained significant when overall survival was analyzed by number of LN examined and grouped into <10, <15 and >15 nodes evaluated (p<0.0001 for all). LN ratio also predicted overall survival in N1 (p=0.04) and N2 (p=0.0002) disease. When comparing LN ratio (χ2=79.5, p<0.0001) to number of LN examined (χ2=4.7, p=0.03), number of positive LN (χ2=38, p<0.0001), number of negative LN (χ2=32, p<0.0001) and AJCC nodal stage (χ2=55.5, p<0.0001), LN ratio appears to be the strongest predictor of overall survival. Conclusion: LN ratio predicts overall survival in patients with resected rectal cancer. Importantly, this is true in patients who have had a small number of LN evaluated, in addition to those with a large number of LN examined. LN ratio also appears to be a stronger predictor of overall survival than other described LN prognostic factors. LN ratio may be a useful variable to stratify outcome in patients with node-positive rectal cancer.

No significant financial relationships to disclose.

Laparoscopic splenectomy in children with hematological disorders: preliminary experience at the Children's Hospital of New Orleans

Minimally invasive surgery has recently gained acceptance as the surgical approach of choice for a variety of surgical disorders in children. Although traditional open surgery is still regarded as the standard approach for a splenectomy in children when necessary for hematologic disorders a few cases of successful laparoscopic splenectomy (LS) have been reported. We present our initial 11 cases of LS in children assessing surgical outcome. Eleven patients ages 2 through 15 years underwent LS between June of 1996 and July of 1999 at the Children's Hospital of New Orleans. Indications for surgery included idiopathic thrombocytopenic purpura, congenital spherocytosis, and hemolytic anemia. In all patients the diameter of the spleen was less than 15 cm. Surgical outcome was assessed according to the following parameters: operative time, postoperative length of stay, postoperative morbidity, and cosmetic results. Data were accumulated on the basis of retrospective chart review. LS was completed in all 11 patients. Postoperative morbidity was minimal and the median postoperative stay was 2.4 days (range 1-5). Mean operative time was 3 hours and 10 minutes (range 1.5-7 hours) with the last six procedures completed in an average of just over 2 hours. Intravenous analgesia was discontinued in <48 hours in all patients. Cosmetic results were judged excellent in all cases. We conclude that LS was safe in children with certain hematologic disorders. Adequate selection of patients, appropriate preoperative preparation of patients, meticulous surgical technique, and careful postoperative care were key factors in obtaining the same long-term results as with open surgery.

High-dose indium 111In pentetreotide radiotherapy for metastatic atypical carcinoid tumor

Indium In 111 pentetreotide imaging of neuroendocrine tumors that overexpress somatostatin receptors has become standard for localization of these tumors. This radioligand is internalized into the cell and can induce receptor-specific cytotoxicity by emission of Auger electrons. We hypothesized that high-dose 111In-pentetreotide could be therapeutic in patients with somatostatin receptor-expressing tumors. Our 35-year-old patient had atypical carcinoid tumor metastatic to cervical, supraclavicular, mediastinal, and mesenteric lymph nodes and to the liver and bone. Chemotherapy had stabilized the disease but with severe gastrointestinal side effects. After a diagnostic 111In-pentetreotide scan, the patient was given eight courses (180 mCi each) of 111In-pentetreotide therapy to selectively target somatostatin receptor-expressing tumor cells. The disease was stable for approximately 14 months. The patient had two additional courses of 111In-pentetreotide therapy (360 mCi each). She died of the disease approximately 18 months after initiation of 111In-pentetreotide therapy.

Suramin analogs inhibit human angiogenesis in vitro

BACKGROUND

Suramin is a polysulfonated naphthylurea that inhibits tumor cell proliferation and angiogenesis, but the widespread use of this drug has been limited by significant neurologic toxicity. A series of suramin analogs that may exhibit less toxicity in vivo have been synthesized. We hypothesized that these novel analogs would have antiangiogenic properties equal to or greater than those of suramin when evaluated in an in vitro human placental vein angiogenesis model.

METHODS

Human placental veins (n = 72 per group) were cultured in a 0.3% fibrin clot for a period of 14 days. Three suramin analogs (NF 145, NF 248, NF 293) and suramin were tested at 56 and 560 microM concentrations to determine their effect on the development of an angiogenic response. Experiments were repeated for each analog on veins from three different placentas. The percentage of wells that initiated an angiogenic response was calculated and compared with initiation in a control group (n = 141).

RESULTS

The three suramin analogs inhibited angiogenesis in a dose-dependent fashion, with all compounds exhibiting near-complete inhibition of angiogenesis at 560 microM. The effects of these analogs were equal to or greater than those of suramin.

CONCLUSION

Suramin analogs with structural alterations inhibit human angiogenesis at concentrations equivalent to those seen in vivo. These analogs may be more effective antiangiogenic agents than suramin and may have less potential for toxicity.

Pancreaticoduodenectomy for melanoma metastatic to the duodenum: a case report and review of the literature

Although melanoma accounts for fewer than 5 per cent of cutaneous malignancies, it is responsible for more than 75 per cent of skin cancer deaths. Metastasis generally proceeds from regional lymph nodes to visceral organs, with the lungs, liver, brain, and bowel being most commonly affected. Herein, we report a case of malignant melanoma metastatic to the ampulla of Vater treated with a pancreaticoduodenectomy.

Extended hemipelvectomy in a Jehovah's Witness with erythropoietin support

The care of patients refusing blood transfusion who require major ablative surgery for malignancy is a continuing challenge. The use of recombinant human erythropoietin is clearly efficacious in patients with renal disease and may be useful in anemic patients who refuse transfusion. Herein, we report a successful extended hemipelvectomy in a Jehovah's Witness using recombinant human erythropoietin support.

Multiply radioiodinated somatostatin analogs induce receptor-specific cytotoxicity

BACKGROUND

Radiolabeled somatostatin analogs have gained popularity for tumor imaging and have recently been used for the treatment of somatostatin receptor-expressing tumors. We have developed a novel, N-terminally extended, multiply iodinated somatostatin analog, 125I-WOC 4a, that we hypothesize will be a useful tool for the detection of and therapy for somatostatin receptor-positive tumors. To evaluate the therapeutic potential of this agent, we compared the cytotoxicity of 125I-WOC 4a in a somatostatin receptor subtype-2 (sst 2)-expressing human neurobalstoma cell line to its cytotoxicity in a somatostatin receptor-negative human pancreatic carcinoma cell line.

METHODS

IMR-32 neuroblastoma cells (sst 2-positive) and PANC-1 human pancreatic cells (sst 2-negative) were incubated with 125I-WOC 4a at doses ranging from 0.1-100 CPM/cell for 48 h and cell viability was assessed by a colorimetric (MTT) cell viability assay. Subsequently, IMR-32 cells were incubated with either control medium, 125I-WOC 4a (1 cpm/cell) alone, 125I-WOC 4a with 10(-6) M octreotide acetate, 125I (1 cpm/cell) alone, 125I with octreotide acetate, or octreotide acetate alone for 48 h, washed, and cryopreserved for 4 weeks. Cells were then thawed, replated, and allowed to acclimate for 48 h. Cell viability was assessed by trypan blue exclusion and a colorimetric assay.

RESULTS

Following short-term exposure, 125I-WOC 4a induced dose-dependent cytotoxicity in IMR-32 cells (P < 0.05 by ANOVA), but not in the PANC-1 cells. After exposure to 125I-WOC 4a (1 cpm/cell) for 48 h followed by a 4-week cryopreserved exposure, significant cytotoxicity was induced in IMR-32 cells (P < 0.05 by ANOVA) which was not seen in cells treated with 125I alone or 125I with 10(-6) M octreotide acetate. Simultaneous exposure to 125I-WOC 4a and octreotide acetate was also cytotoxic.

CONCLUSION

125I-WOC 4a induces receptor-specific cytotoxicity following both short- and long-term drug exposures. This radiopharmaceutical may be useful for localizing or treating somatostatin receptor-positive tumors.

Breast cancer increases initiation of angiogenesis without accelerating neovessel growth rate

BACKGROUND

Recurrence and mortality rates in patients with breast cancer correlate with the degree of tumor angiogenesis (angiogenic index). We have developed a novel angiogenesis model by using disks of fresh human placental vein that initiate an angiogenic response and exhibit linear radial capillary growth in culture. We hypothesized that the addition of human breast cancer cells to this human placental vein angiogenesis model would increase the incidence of angiogenesis and accelerate the rate of neovessel growth compared with vein disk cultured without tumor cells.

METHODS

To test this hypothesis, vein explants from seven human placentas were incorporated into clots of 0.3% fibrin in Medium 199 and fetal bovine serum with or without 1.5 x 10(5) T-47D (n = 6 placentas) or MCF-7 (n = 1 placenta) breast cancer cells. Statistical differences between the experimental (with breast cancer cells) and control (no added cells) cultures were determined by repeated measures ANOVA.

RESULTS

The proportion of disks exhibiting neovessel growth (initiation) by day 12 was significantly increased in the presence of T-47D cells (p < 0.05 at day 12, p < 0.001 at day 15). No statistical difference was seen in rates of neovessel growth (millimeters per day). Similar results were seen with MCF-7 cells.

CONCLUSIONS

Tumor enhancement of angiogenesis may occur by increased initiation of the angiogenic response. Subsequent vessel growth rates may be tumor independent. We predict that effective antiangiogenic therapies will block a tumor's ability to augment angiogenesis initiation rather than subsequent neovessel growth.