SU-E-J-127: An Initial Application of Evaluating Lung Tumor Motion Throughout Radiotherapy

PURPOSE

We present a novel method for evaluating lung tumor motion incorporating planning CT scan, imaging for patient localization, and during treatment delivery.

METHODS

Tumor motion is evaluated at three stages of the treatment process. Following the acquisition of 4D CT scans for treatment planning, tumors are contoured at one phase and registered to other phases to obtain tumor motion patterns. Tumor motion prior to each treatment is evaluated by identifying tumors directly on every raw projection of the daily localization CBCT scans. Finally, tumor motion during treatment is evaluated by analyzing MV treatment beam images. Every frame of image is evaluated as three components, each with separate DRRs: all non-moving structures, the tumor, and other moving structures. The locations of three components are determined though a registration process. In order to quantify tumor motion, the cumulated probability, the percentage of time when the tumor motion is equal to or smaller than a given range, is evaluated at every stage.

RESULTS

This methodology has been applied to five lung cancer patients undergoing radiotherapy. More than 5400 frames from MV treatment beam images and 24 CBCT scans were acquired from 12 fractions. Both the average tumor position and the cumulated probability with the range were evaluated. The tumor motion ranges are generally larger than those obtained from 4D CT. Significant variation in motion patterns was observed as well.

CONCLUSIONS

Information obtained from 4DCT is insufficient for motion assessment. In contrast, our novel methodology is capable of accurately characterizing lung tumor motion on a daily basis, without the need for implanted fiducial markers and without additional imaging dose. It provides daily verification that the tumor range is within prior estimates and covered by the treatment planning volume. This research is supported by CPRIT Individual Investigator Award RP110329.

P3-01-04: Differential Impact of Gefitinib and PLX4720 on Proliferation of MCF10A and Isogenic Lines as Measured with a Metastasis Expression Score

Background: We previously reported that a published “Metastasis Score” (MS) could be used to evaluate the effects of a PI3K inhibitor (GDC-0941) on mutated human isogenic breast cancer cell lines. MS, based on the expression of14 genes, has been shown to predict distant metastasis in ER(+), node (−), breast cancer. We were interested to determine the impact of gefitinib (EGFR inhibitor) and PLX-4720 (selective inhibitor of BRAF V600E) on MS to assess the applicability of this score to a broader class of targeted agents. In addition, given the cross-talk between metabolism and proliferation, we also profiled genes involved in glycolysis, fatty acid metabolism and oxidative phosphorylation.

Methods: Parental MCF10A (WT for all genes) and isogenic lines of MCF10A harboring PI3K (H1047R), p53 null or KRAS(G12V) mutations were cultured overnight in DMEM:F12 media under identical conditions. Cells were then treated with gefitinib, PLX4720, or DMSO (vehicle control) and further incubated for 24hr. Expression analysis was performed by RT-PCR.

Results: The MS of the PI3K (H1047R) and p53 null lines was higher than the parental line and lower for the KRAS (G12V) line. Treatment of parental, PI3K and KRAS cell lines with gefitinib resulted in dose-dependent decreases in MS, as reported for GDC-0941, with a higher dose required to inhibit growth of PI3K (H1047R) cells. Treatment of p53 null cells with gefitinib, however, had only a modest effect on MS. In contrast to gefitinib, MS increased with PLX-4720 treatment in all 4 lines; the greatest increase was observed in KRAS (G12V) cells. The expression of metabolic genes differed significantly depending on the oncogenic mutation harbored by the cell line. ACTA2, ACLY, RPIA, KHK, GLS2 were most highly expressed in p53 null but lowest in KRAS (G12V), while GLUT5, PFKFB4, ENO3, SLC27A1, PGK2, GLUT1, TKT were expressed most highly in KRAS (G12V) but lowest in PI3K(H1047R). Upon treatment with gefitinib or PLX-4720, genes that were downregulated in the mutated lines generally showed a dose-dependent increase; those that were upregulated relative to the parental, showed a dose-dependent decrease with treatment.

Discussion: The decrease in MS of the parental, PI3K (H1047R) and KRAS (G12V) cell lines treated with gefitinib supports the impact of this EGFR inhibitor on cell proliferation. The modest effect on MS in p53 null cells supports the findings that sensitivity to gefitinib requires active p53 in order to induce apoptosis through a p53-dependent pathway. Increases in MS were observed in all 4 cell lines treated with PLX-4720, with the largest increase observed in KRAS (G12V). The enhanced proliferation of a BRAF WT cell line with a KRAS mutation is consistent with the Ras-dependent nature of this pathway. The metabolic genes showed diverse expression patterns that differed with different oncogenic mutations and likely reflect the multiple mechanisms controlling metabolism in cancer. An improved understanding of the expression of metabolic genes relative to proliferation in cell lines with various oncogenic mutations may provide additional insights into the dysregulation of these cellular processes and the possible role of anti-metabolite intervention.

Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P3-01-04.

Sciatic nerve injury induces functional pro-nociceptive chemokine receptors in bladder-associated primary afferent neurons in the rat

Visceral sensory afferents during disease or following injury often produce vague, diffuse body sensations, and pain referred to somatic targets. Alternatively, injury due to trauma or disease of somatic nerve targets can also lead to referred pain in visceral targets via a somatovisceral reflex. Both phenomenons are thought to be due to convergence of visceral and somatic afferents within the spinal cord. To investigate a potential peripheral influence for referred pain in visceral targets following somatic nerve injury, we examined whether a sciatic nerve injury known to produce hindpaw tactile hyperalgesia alters the frequency of micturition and the sensitivity of bladder-associated sensory neurons to pro-nociceptive chemokines. Adult female Sprague-Dawley rats received injections of cholera toxin B subunit conjugated to 555 into urinary bladder wall to retrogradely label visceral primary afferent neurons. After 7 days, the right sciatic nerve of these animals was subjected to a lysophosphatidylcholine (LPC)-induced focal demyelination injury. Pre- and post-injury tactile sensitivity in the hind paw and micturition frequency were assayed. Animals were allowed to survive for 14-28 days. Lumbosacral and lumbar dorsal root ganglia (DRG) ipsilateral to the nerve injury were acutely dissociated from sham and nerve injured animals. Bladder wall-associated sensory neurons identified via the retrograde marker were assayed for fluxes in intracellular calcium following administration of pro-nociceptive chemokines. The assayed chemokines included monocyte chemoattractant protein-1 (MCP1/CCL2) and stromal cell derived factor-1 alpha (SDF1/CXCL12). LPC nerve injured animals exhibited tactile hyperalgesia and increased micturition frequency for at least 28 days. Focal demyelination of the sciatic nerve also increased the number of injured L₄L₅ and non-injured L₆-S₂ bladder-associated sensory neurons that responded to MCP1 and SDF1 when compared with sensory neurons derived from uninjured naïve and sham-injured control animals. Taken together, these data suggest that some visceral hypersensitivity states may have a somatic origin. More importantly, nociceptive somatovisceral sensation may be mediated by upregulation of chemokine signaling in visceral sensory neurons.

Use of intravenous immune globulin in the ICU: a retrospective review of prescribing practices and patient outcomes

RATIONALE

Intravenous immune globulin (IVIG) is a pooled human blood product. Much of IVIG use in Canada is prescribed for 'unlabelled' or 'off-label' indications. Due to costs, risk of use and limited supply, knowledge about the use of IVIG is important. We collected data regarding the usage of IVIG and outcomes of patients receiving IVIG in the intensive care units (ICUs) of two community and three academic hospitals.

METHODS

We reviewed the charts of adult patients who received IVIG in the five ICUs over a 5-year period. Data collection included demographics, severity of illness, indication for and dose of IVIG, mortality and adverse effects. On the basis of a classification developed by Canadian Blood Services, the indications for IVIG were then classified as 'appropriate' or 'inappropriate'.

RESULTS

One hundred and forty-five patients received IVIG in the ICU. In all, 19% of IVIG prescriptions were for 'appropriate' indications and 7% were 'inappropriate'. The remaining 74% were prescribed for indications with some evidence to support their use. Three indications accounted for 50% of all IVIG prescribed: Guillain-Barre syndrome (GBS), necrotising fasciitis (NF) and toxic epidermal necrolysis (TEN). Both the community and academic centres prescribed IVIG for similar indications. Adverse effects associated with IVIG administration included deep vein thrombosis/pulmonary embolism, fever and renal failure, although direct causation related to IVIG could not be established. The overall mortality rate was 55%.

CONCLUSIONS

IVIG is used relatively infrequently in the critical care setting. The most common indications were GBS, TEN and NF. Mortality was high. There was no difference between community and academic ICUs.

Successful treatment of severe male factor infertility in Jamaica with intracytoplasmic sperm injection

OBJECTIVE

To examine the impact of intracytoplasmic sperm injection (ICSI) on the treatment of subfertile couples in Jamaica.

METHOD

A review of the outcome of treatment cycles for infertile couples that underwent in-vitro fertilisation (IVF) and ICSI from 2003-05 at the Hugh Wynter Fertility Management Unit (HWFMU) of the University of the West Indies. Fertilisation and pregnancy rates for the cycles as well as the factors determining the success of the procedure were reviewed. SPSS 11.1 was used to do statistical calculations.

RESULTS

Ninety-six ICSI cycles were done from January 1, 2003 to December 31, 2005. For couples with previous poor or no fertilisation in a standard IVF group (n = 12), the fertilisation rate was 72%; for those with substandard semen (n = 73), the fertilisation rate was 77.5%, for those with semen retrieved by surgical sperm method (n = 11), the fertilisation rate was 59%. The resulting live births were 0%, 12.5% and 27.3% respectively. There was a statistically significant impact of age on pregnancy rates as the mean age of the females in the previously poor or no fertilisation in a standard IVF group (39.08 +/- 5.14) was greater than those of the substandard semen group (35.93 +/- 4.22) [p = 0.023] as well as the group with surgical sperm retrieval (32.82 +/- 6.65) [p = 0.019].

CONCLUSION

With ICSI, the fertilisation and pregnancy rates in Jamaica are comparable to international rates regardless of the cause of infertility. However, the age of the female partner does have a significant impact on the pregnancy rate following ICSI.

Abstract P5-14-02: Immediate Breast Reconstruction: The Effect of Radiation

Background:

Prior history of breast irradiation or anticipated need for postmastectomy radiation have been considered relative contraindications for immediate breast reconstruction. We evaluated the surgical outcomes between three groups of patients: patients without radiation exposure, those with radiation prior to immediate reconstruction, and those with radiation following immediate reconstruction to determine the differences in risk of post-surgical complications among groups. Methods:

All patients undergoing mastectomy and immediate reconstruction with either a tissue expander or implant between January 1, 2005 and June 30, 2009 were entered into an IRB-approved prospective database. Routine institutional protocol consisted of immediate reconstruction with tissue expander, expansion during the1-2 months following surgery, radiation if indicated, followed by implant exchange at 3-6 months after completion of radiation. All complications were collected and recorded within a week of the event, and all patients had a minimum follow-up period of 6 months after implant exchange to allow for sufficient monitoring of complications. Major complications included infection requiring IV antibiotics, unplanned return to surgery, and tissue expander/implant loss. Results:

A total of 446 mastectomies were identified. Of these, 341 had no radiation history, 33 had prior ipsilateral breast radiation, and 72 had post-mastectomy radiation. Overall, there were 160 major complications (36%), including 50 (11%) expander/implant losses. Patient age, BMI, diabetes, and history of tobacco use were not associated with increased risk of major complications in this cohort. However, both prior and postoperative radiation was associated with higher risk of both major complications and implant loss.

Conclusion:

Immediate reconstruction with implant or tissue expander is associated with a 36% risk of major postoperative complications, with the greatest number seen in those patients with history of previous chest wall irradiation. However, most implants were salvaged even in the setting of complications, and the overall implant loss rate was only 8% in unirradiated patients and 22% in those patients with postoperative RT. Although radiation history is not a contraindication to immediate breast reconstruction, patients undergoing this procedure must be well informed of their substantial risk of postoperative complications.

Muscarinic type 2 receptors in the lateral dorsal tegmental area modulate cocaine and food seeking behavior in rats

The cholinergic input from the lateral dorsal tegmental area (LDTg) modulates the dopamine cells of the ventral tegmental area (VTA) and plays an important role in cocaine taking. Specific pharmacological agents that block or stimulate muscarinic receptors in the LDTg change acetylcholine (ACh) levels in the VTA. Furthermore, manipulations of cholinergic input in the VTA can change cocaine taking. In the current study, the ACh output from the LDTg was attenuated by treatment with the selective muscarinic type 2 (M2) autoreceptor agonist oxotremorine.sesquifumarate (OxoSQ). We hypothesized that OxoSQ would reduce the motivation of rats to self-administer both natural and drug rewards. Animals were tested on progressive ratio (PR) schedules of reinforcement for food pellets and cocaine. On test days, animals on food and on cocaine schedules were bilaterally microinjected prior to the test. Rats received either LDTg OxoSQ infusions or LDTg artificial cerebrospinal fluid (aCSF) infusions in a within-subjects design. In addition, infusions were delivered into a dorsal brain area above the LDTg as an anatomical control region. OxoSQ microinjection in the LDTg, compared to aCSF, significantly reduced both the number of self-administered pellets and cocaine infusions during the initial half of the session; this reduction was dose-dependent. OxoSQ microinjections into the area just dorsal to the LDTg had no significant effect on self-administration of food pellets or cocaine. Animals were also tested in locomotor activity chambers for motor effects following the above microinjections. Locomotor activity was mildly increased by OxoSQ microinjection into the LDTg during the initial half of the session. Overall, these data suggest that LDTg cholinergic neurons play an important role in modifying the reinforcing value of natural and drug rewards. These effects cannot be attributed to significant alterations of locomotor behavior and are likely accomplished through LDTg muscarinic autoreceptors.