Sarah L. Cohen

Conditional expression of oncogenic K-ras from its endogenous promoter induces a myeloproliferative disease

Oncogenic ras alleles are among the most common mutations found in patients with acute myeloid leukemia (AML). Previously, the role of oncogenic ras in cancer was assessed in model systems overexpressing oncogenic ras from heterologous promoters. However, there is increasing evidence that subtle differences in gene dosage and regulation of gene expression from endogenous promoters play critical roles in cancer pathogenesis. We characterized the role of oncogenic K-ras expressed from its endogenous promoter in the hematopoietic system using a conditional allele and IFN-inducible, Cre-mediated recombination. Mice developed a completely penetrant myeloproliferative syndrome characterized by leukocytosis with normal maturation of myeloid lineage cells; myeloid hyperplasia in bone marrow; and extramedullary hematopoiesis in the spleen and liver. Flow cytometry confirmed the myeloproliferative phenotype. Genotypic and Western blot analysis demonstrated Cre-mediated excision and expression, respectively, of the oncogenic K-ras allele. Bone marrow cells formed growth factor-independent colonies in methylcellulose cultures, but the myeloproliferative disease was not transplantable into secondary recipients. Thus, oncogenic K-ras induces a myeloproliferative disorder but not AML, indicating that additional mutations are required for AML development. This model system will be useful for assessing the contribution of cooperating mutations in AML and testing ras inhibitors in vivo.

FGFR3 as a therapeutic target of the small molecule inhibitor PKC412 in hematopoietic malignancies

Reccurent chromosomal translocation t(4;14) (p16.3;q32.3) occurs in patients with multiple myeloma (MM) and is associated with ectopic overexpression of fibroblast growth factor receptor 3 (FGFR3) that sometimes may contain the activation mutations such as K650E thanatophoric dysplasia type II (TDII). Although there have been significant advances in therapy for MM including the use of proteasome inhibitors, t(4;14) MM has a particularly poor prognosis and most patients still die from complications related to their disease or therapy. One potential therapeutic strategy is to inhibit FGFR3 in those myeloma patients that overexpress the receptor tyrosine kinase due to chromosomal translocation. Here we evaluated PKC412, a small molecule tyrosine kinase inhibitor, for treatment of FGFR3-induced hematopoietic malignancies. PKC412 inhibited kinase activation and proliferation of hematopoietic Ba/F3 cells transformed by FGFR3 TDII or a TEL-FGFR3 fusion. Similar results were obtained in PKC412 inhibition of several different t(4;14)-positive human MM cell lines. Furthermore, treatment with PKC412 resulted in a statistically significant prolongation of survival in murine bone marrow transplant models of FGFR3 TDII-induced pre-B cell lymphoma, or a peripheral T-cell lymphoma associated TEL-FGFR3 fusion-induced myeloproliferative disease. These data indicate that PKC412 may be a useful molecularly targeted therapy for MM associated with overexpression of FGFR3, and perhaps other diseases associated with dysregulation of FGFR3 or related mutants.

Contained power morcellation within an insufflated isolation bag.

OBJECTIVE: To describe a technique for contained power morcellation within an insufflated isolation bag at the time of uterine specimen removal during minimally invasive gynecologic procedures. METHODS: Over the study period of January 2013 to April 2014, 73 patients underwent morcellation of the uterus or myomas within an insufflated isolation bag at the time of minimally invasive hysterectomy or myomectomy. This technique involves placing the specimen into a large plastic bag within the abdomen, exteriorizing the opening of the bag, insufflating the bag within the peritoneal cavity, and then using a power morcellator within the bag to remove the specimen in a contained fashion. Procedures were performed at four institutions and included multiport laparoscopy, single-site laparoscopy, multiport robot-assisted laparoscopy, or single-site robot-assisted laparoscopy. Demographic and perioperative characteristics were collected for the cases. RESULTS: Surgical specimen morcellation within an insufflated isolation bag was successfully used in all cases. The median operative time was 114 minutes (range 32–380 minutes), median estimated blood loss was 50 mL (range 10–500 mL), and the median specimen weight was 257 g (range 53–1,481 g). There were no complications related to the contained morcellation technique nor was there visual evidence of tissue dissemination outside of the isolation bag. CONCLUSION: Morcellation within an insufflated isolation bag is a feasible technique. Methods for morcellating uterine tissue in a contained manner may provide an option to minimize the risks of open power morcellation while preserving the benefits of minimally invasive surgery. LEVEL OF EVIDENCE: II

Open Power Morcellation Versus Contained Power Morcellation Within an Insufflated Isolation Bag: Comparison of Perioperative Outcomes

STUDY OBJECTIVE To compare perioperative outcomes, particularly operative time, between uncontained and in-bag power morcellation of uterine tissue at the time of laparoscopic surgery. DESIGN Canadian Task Force classification II-3. SETTING Academic tertiary care hospitals. PATIENTS Women undergoing laparoscopic hysterectomy or myomectomy who required morcellation of uterine tissue for specimen extraction. INTERVENTIONS Outcomes among patients who had in-bag power morcellation were compared with outcomes among patients who had traditional power morcellation. The technique for in-bag morcellation entails placing the specimen into a large containment bag within the abdomen, insufflating the bag within the peritoneal cavity, and then using a power morcellator to remove the specimen from inside the bag. MEASUREMENTS AND MAIN RESULTS The cohort consisted of 85 consecutive patients who underwent surgery with morcellation of uterine tissue. Prospective data collected from 36 patients who underwent in-bag morcellation were compared with retrospective data collected from the immediately preceding 49 patients who had uncontained power morcellation. Baseline demographics were comparable between the 2 groups although women who underwent in-bag morcellation were on average older than the open morcellation group (mean age in years [standard deviation], 49.19 [1.12] vs 44.06 [8.93]; p = .01). The mean operating room time was longer in the in-bag morcellation group (mean time in minutes [standard deviation], 119.0 [55.91] vs 93.13 [44.90]; p = .02). The estimated blood loss, specimen weight, hospital length of stay, and perioperative complication rate did not vary between the 2 groups. Operative times did not vary significantly by surgeon. There were no cases of malignancy or isolation bag disruption. CONCLUSIONS In-bag power morcellation, a tissue extraction technique developed to reduce the risk of tissue dissemination, results in perioperative outcomes comparable with the traditional laparoscopic approach. In this cohort, the mean operative time was prolonged by 26 minutes with in-bag morcellation but may potentially be reduced with further refinement of the technique.

In-Bag Morcellation

In-bag morcellation seems to be a viable alternative to open power morcellation and offers the advantage of minimal to no spillage of tissue or fluids during morcellation. We report our initial experience and technique using this approach.

Risk of Leakage and Tissue Dissemination With Various Contained Tissue Extraction (CTE) Techniques: An in Vitro Pilot Study

STUDY OBJECTIVE To evaluate risk of leakage and tissue dissemination associated with various contained tissue extraction (CTE) techniques. DESIGN In vitro study (Canadian Task Force classification: II-1). SETTING Academic hospital simulation laboratory. INTERVENTION Beef tongue specimens weighing 400 to 500 g were stained using 5 mL indigo carmine dye and morcellated under laparoscopic guidance within a plastic box trainer. CTE was performed via 3 different techniques: a stitch-sealed rip-stop nylon bag and multi-port approach; a one-piece clear plastic 50 × 50-cm isolation bag and multi-port approach; or a 1-piece clear plastic 50 × 50-cm isolation bag and single-site approach. Four trials of each CTE method were performed and compared with an open morcellation control. All bags were insufflated to within 10 to 25 mmHg pressure with a standard CO2 insufflator. Visual evidence of spilled tissue or dye was recorded, and fluid washings of the box trainer were sent for cytologic analysis. MEASUREMENTS AND MAIN RESULTS Blue dye spill was noted in only 1 of 12 CTE trials. Spillage was visualized from a seam in 1 of the 4 stitch-sealed rip-stop nylon bags before morcellation of the specimen. The only trial in which gross tissue chips were visualized in the box trainer after morcellation was the open morcellation control. However, cytologic examination revealed muscle cells in the open morcellation washings and in the washings from the trial with dye spill. Muscle cells were not observed at cytologly in any of the other samples. CONCLUSION CTE did not result in any leakage or tissue dissemination with use of the single-site or multi-port approach when using a 1-piece clear plastic 50 × 50-cm isolation bag. Further studies are needed to corroborate these findings in an in vivo context and to evaluate use of alternate bag options for specimen containment.

Laparoendoscopic single-site surgery in gynecology

Purpose of review To review the contemporary literature on laparoendoscopic single-site surgery (LESS) advances in gynecology. Recent findings Minimally invasive surgery has become a standard of care for the treatment of many benign and malignant gynecologic conditions. Both conventional laparoscopy and robotic assisted surgery have impacted the entire spectrum of gynecologic surgery. Ongoing efforts to improve upon the morbidity and cosmetic sequelae of laparoscopic surgery have led to minimization of size and number of ports required for these procedures. LESS surgery is a recently coined surgical term used to describe various techniques that aim at performing laparoscopic surgery through a single, small skin incision concealed within the umbilicus. LESS surgery is not a new endeavor but recent developments in surgical technology and techniques have resulted in an exponential increase in utilization of LESS across many surgical subspecialties. Recently published outcome data demonstrate feasibility, safety and reproducibility for LESS in gynecology. The contemporary LESS literature, gamut of gynecologic procedures and limitations of current technology will be reviewed in this article. Summary LESS represents the latest innovation in minimally invasive surgery but comparative data and prospective trials are required to determine the clinical impact of LESS in treatment of gynecologic conditions.

Contained tissue extraction using power morcellation: prospective evaluation of leakage parameters

BACKGROUND Safe tissue removal is a challenge for minimally invasive procedures such as myomectomy, supracervical hysterectomy, or total hysterectomy of a large uterine specimen. There is concern regarding disruption or dissemination of tissue during this process, which may be of particular significance in cases of undetected malignancy. Contained tissue extraction techniques have been developed in an effort to mitigate morcellation-related risks. OBJECTIVE The objective of the study was to quantify perioperative outcomes of contained tissue extraction using power morcellation, specifically evaluating parameters of tissue or fluid leakage from within the containment system. STUDY DESIGN This was a study including a multicenter prospective cohort of adult women who underwent minimally invasive hysterectomy or myomectomy using a contained power morcellation technique. Blue dye was applied to the tissue specimen prior to removal to help identify cases of fluid or tissue leakage from within the containment system. RESULTS A total of 76 patients successfully underwent the contained power morcellation protocol. Mean time for the contained morcellation procedure was 30.2 minutes (±22.4). The mean hysterectomy specimen weight was 480.1 g (±359.1), and mean myomectomy specimen weight was 239.1 g (±229.7). The vast majority of patients (73.7%) were discharged home the same day of surgery. Final pathological diagnosis was benign in all cases. Spillage of dye or tissue was noted in 7 cases (9.2%), although containment bags were intact in each of these instances. CONCLUSION Findings are consistent with prior work demonstrating the feasibility of contained tissue extraction; however, further refinement of this technique is warranted.

Barbed Versus Standard Suture: A Randomized Trial for Laparoscopic Vaginal Cuff Closure

STUDY OBJECTIVE To compare closure times, cuff healing, and postoperative dyspareunia between barbed and traditional sutures during laparoscopic total hysterectomy. DESIGN A randomized clinical trial (Canadian Task Force classification I). SETTING A university hospital. PATIENTS Sixty-three women undergoing total laparoscopic hysterectomy. INTERVENTIONS Total laparoscopic hysterectomy was performed using standard techniques. The vaginal cuff closure method was randomized to barbed suture (Quill; Angiotech Pharmaceuticals, Inc., Vancouver, Canada) or standard suture (Vicryl; Ethicon Inc., Somerville, NJ). The time required for cuff closure was documented. Patients were examined postoperatively to assess cuff healing, and a standardized sexual function questionnaire was administered preoperatively and at 3 months postoperatively. MEASUREMENTS AND MAIN RESULTS The mean vaginal cuff closure time was 10.4 minutes versus 9.6 minutes in the barbed versus standard suture group (p = .51). Cuff healing appeared similar between the 2 groups. Rates of dyspareunia, partner dyspareunia, and sexual function were similar in both groups at 3 months postoperatively. Vaginal cuff closure times were significantly faster among attendings compared with residents/fellows (7.1 vs. 12.8 minutes, respectively; p < .0001). The study was designed to have a statistical power of 80% to detect a difference of 5 minutes in cuff closure time between the 2 groups (α level of 0.05). CONCLUSION Laparoscopic vaginal cuff closure times are similar when using barbed sutures and braided sutures.

Utility of Cystoscopy During Hysterectomy

OBJECTIVE: To estimate the incidence of cystoscopy use at time of hysterectomy and its use to detect urinary tract injury. METHODS: This was a retrospective cohort study in a tertiary care academic center of 1982 patients who underwent a hysterectomy for any indication (excluding obstetric) between January 2009 and December 2010. Medical records were reviewed for baseline and perioperative characteristics, cystoscopy use, and information about bladder or ureteral injury related to hysterectomy. RESULTS: Two hundred fifty-one women (12.66%, 95% confidence interval [CI] 11.23–14.21%) underwent a cystoscopy at the time of hysterectomy with no reported complications resulting from the cystoscopy procedure. Cystoscopy was most frequently used by low-volume surgeons and in cases involving prolapse or vaginal mode of access. Fourteen patients (0.71%, 95% CI 0.39–1.19%) experienced bladder injury and five patients (0.25%, 95% CI 0.08–0.58%) sustained ureteral injury. None of these complications were detected by cystoscopy; cystoscopy was either normal at the time of hysterectomy or was omitted. The presence of adhesions was significantly associated with bladder injury at the time of hysterectomy (P=.006). Low-volume surgeon and laparoscopic or robotic mode of access were both significantly associated with ureteral injury (P=.023 and P=.042, respectively). CONCLUSIONS: Our data support selective rather than universal cystoscopy at the time of hysterectomy. LEVEL OF EVIDENCE: II