Prospective study of genetic mutations in matched tumor and plasma specimens in colorectal cancer patients

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Background: Circulating free DNA (cfDNA) represents a minimally-invasive resource for detecting mutations in advanced cancer patients. The primary objective of this study was to determine if cfDNA is representative of tumor tissue for multiplex mutation detection utilizing Sequenom MassARRAY.

Methods: Samples were spiked with dilutions (10ng/μl to 0.01ng/μl) of HCT116 DNA containing KRAS G13D mutations to determine assay sensitivity and specificity. Metastatic colorectal cancer patients referred to the Drug Development Unit at the Royal Marsden Hospital between 9/09-8/10 gave their consent to provide DNA from matched archival formalin fixed paraffin-embedded (FFPE) tumor and plasma. Samples had ∼200 described gene mutations genotyped using Sequenom MassARRAY (OncoCarta Panel).

Results: Serial dilution spiking experiments revealed that the KRAS G13D mutation was reproducibly detectable to 40ng/mL of HCT116 DNA; 26 patient samples were then analyzed. KRAS, BRAF and PIK3CA mutations were detected in 8 (31%), 3 (12%) and 3 (12%) tumor specimens respectively; 100% concordance for KRAS status was observed between multiple FFPE biopsies from the same patient and analysis by Amplification Refractory Mutation System (ARMS)-Scorpion PCR. The median quantity of cfDNA was 353ng/ml (range 106-4603). Concordance between matched FFPE and cfDNA was 88% for KRAS and 100% for BRAF mutations. No patients with wildtype KRAS or BRAF tumor genotypes had mutations in their respective cfDNA confirming the high specificity of cfDNA analysis. Three patients had detectable PIK3CA mutations; 1 patient had a E346K mutation detected in both FFPE tissue and plasma; 1 patient had E545K detected only in FFPE and the other had E542K detected in a liver metastasis but not in the colorectal primary or plasma. The recently reported oncogenic AKT1 E17K mutation was detected in 1 patient in tissue and plasma. No mutations in any of the other tested oncogenes studied were detected.

Conclusions: A high concordance in detected mutations was observed between FFPE tumor and matched cfDNA. cfDNA is representative of tumor DNA and may be used for the prospective selection of cancer patients for treatment with targeted therapeutics.

No significant financial relationships to disclose.

Acute Skin Toxicity in Breast Cancer Patients Receiving Post-operative Radiotherapy

Post-operative radiotherapy to the breast is a standard treatment for the management of breast cancer. Treatment-related skin toxicity will occur in many patients and usually develops two to three weeks into treatment and may persist for up to four weeks post therapy. Management of acute toxicity remains a challenge for oncology professionals because there is very limited evidence-based research that addresses interventions for the prevention and management of radiation skin damage. Forty breast cancer patients being treated with radiotherapy at Al Amal Hospital were evaluated for the frequency and the severity of acute skin reactions. Clinical skin evaluation was performed by the same Radiation Oncologist during weekly reviews and on the last day of treatment. Normal tissue damage was scored according to the Radiation Therapy Oncology Group side-effect scales. The most frequent acute complications were erythema and dry desquamation, although moist desquamation was a problem in high friction anatomical sites. The reactions were classified as severe (RTOG’2) in only one case. There was remarkable consistency in the assessment and documentation of patient education among nurses following the hospital's standard practice.

Clinical Data Do Not Support the Hypothesis That Irradiation Promotes Biologically Aggressive Local Recurrences through Stromal Activation

Objective: Recent data in select pre-clinical models suggest that radiation can activate normal stroma to promote tumor metastases and aggressiveness. We hypothesized that if these were occurring clinically, there would be a lower survival after locoregional recurrence (LRR) in patients after post-mastectomy radiation therapy (PMRT) compared to mastectomy (Mx) alone. This study used two independent datasets to compare survival after LRR in women treated with versus without PMRT.Methods: Data from 229 of 1,505 patients who experienced LRR after treatment on sequential non-randomized institutional prospective trials at the MD Anderson Cancer Center (MDA) and 66 of 318 patients enrolled in the British Columbia (BC) PMRT randomized trial who experienced LRR were analyzed. All patients underwent Mx and level I/II axillary dissection. In both data sets analysis was based on treatment received. Patients from MDA received doxorubicin based chemotherapy +/- PMRT, with 45 LRR after PMRT and 184 LRR after Mx alone). Patients treated on the BC trial received CMF chemotherapy +/- PMRT, with LRR in 14/160 after PMRT versus 52/158 after Mx alone. Survival was calculated from time of LRR to death using Kaplan-Meier and log rank statistics.Results:MDA Data: Median follow up of living patients was 192 months. Analyzing data from all patients with LRR regardless of distant metastasis (DM), patients with LRR after PMRT were younger (47 vs. 51 y, p = 0.033) and had shorter time to first LRR (40mo vs. 51 mo, p = 0.018). 5-yr/10-yr OS were 31%/16% without PMRT and 20%/7% after PMRT (p = 0.008). However, PMRT-treated patients had increased risk factors for DM (advanced T and N stage) and more PMRT-treated patients developed DM prior to LRR (58% vs. 36% p = 0.009). Analyzing only patients without DM there was no difference in OS between groups (p = 0.67), and a separate analysis of all patients who developed metastatic disease (N = 385 no PMRT, 233 after PMRT) revealed no difference in 5 or 10-yr OS after DR (15%/4% without PMRT vs. 13%/6% after PMRT, p = 0.5).BC Data: Median follow up of living patients was 235 months. The distributions of age, T stage, N stage, grade, LVI, ER status, excised nodes and nodal ratio were similar between patients with LRR after Mx alone vs. Mx plus PMRT. (all p > 0.05). The mean time to first LRR was 39 mo in patients treated with Mx alone and 57 mo in patients treated with PMRT, p= 0.27). The rate of DM was similar in patients with LRR after Mx with vs without PMRT (93% vs. 96%, p=0.60). Distant relapse free survival after LRR was similar in Mx alone vs. PMRT-treated patients (log rank p=0.75). Overall survival was also similar in the two groups (5-yr/10-yr OS 21%/8% without PMRT vs. 23%/12% with PMRT, log rank p=0.93).Conclusions: Decades of randomized data have demonstrated that PMRT reduces LRR and improves overall survival. In the non-randomized dataset, removing the competing risk of DM which is higher in patients selected for PMRT by studying patients with isolated LRR, we find no difference in survival after LRR in the PMRT setting. Analysis of the randomized PMRT trial dataset confirmed the finding of similar survival among women with LRR irrespective of PMRT use.

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 4101.

Local-regional recurrence with and without radiation after neoadjuvant chemotherapy and mastectomy for T3N0 breast cancer patients

Abstract #74

Purpose: The goal of this study was to compare the local-regional recurrence (LRR) risk in patients with clinical T3N0 breast cancer who were treated with neoadjuvant chemotherapy (NeoChemo) and mastectomy (Mastx) according to the use of adjuvant radiation (RT).
 Methods: Clinicopathologic data from 164 patients with clinical T3N0 breast cancer who received NeoChemo and Mastx from 1985 to 2004 were retrospectively reviewed. In this cohort, 121 (74%) patients received adjuvant radiation (RT) while 43 (26%) patients did not. The median number of axillary lymph nodes (LN) dissected was 15. After NeoChemo, 54% of patients (n=89) had no pathologically involved lymph nodes at the time of surgery (ypLN-) while 46% (n=75) had at least 1 lymph node pathologically positive (ypLN+). Actuarial rates were calculated using Kaplan-Meier analysis and compared using log-rank test. Cox proportional hazards models were fit to determine the association of RT with the risk of LRR after adjustment for other patient and disease characteristics.
 Results: At a median follow-up of 77 months, 17 of the 164 patients had a LRR. For all patients, the 5-year local-regional control rates (5-yr LRC) were 90%. The 5-yr LRC for those who received RT (n=121) was 95% and for those who did not received RT (n=43) was 76% (p = 0.002), with a higher proportion of the patients who received RT having pathologically involved LN (+RT 53% vs –RT 23%, p=0.002).
 Among the entire cohort, the 5-yr LRC was 85% for patients with ypLN+ disease and 94% for patients with ypLN- disease (p=0.093). In patients with ypLN+, the 5-yr LRC with no RT (n=11) was 47% and with RT (n=64) was 92% (p<0.001). In patients with ypLN-, the 5-yr LRC with no RT (n=32) was 86% and with RT (n=57) was 98% (p=0.063). Patients who had tumors with high nuclear grade had worse 5-yr LRC (Grade low 100%, intermediate 97%, high 81%, p=0.023). The presence of lymphovascular invasion, close/positive margin, or estrogen receptor status did not statistically correlate with LRC. In a Cox regression model, patients with tumor exhibiting high nuclear grade (Hazard Ratio (HR) 5.0, 95% Confidence Interval (CI) 1.6-15.4), ypLN+ (HR 6.6, 95% CI 2.0-22.1) and no adjuvant RT (HR 7.6, 95% CI 2.4-24.0) had increased risk of LRR.
 Conclusions: Post mastectomy adjuvant RT appears to improve LRC in clinical T3N0 breast cancer patients treated with neoadjuvant chemotherapy and mastectomy.

Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 74.

A d.c. magnetic metamaterial

Electromagnetic metamaterials are a class of materials that have been artificially structured on a subwavelength scale. They are currently the focus of a great deal of interest because they allow access to previously unrealizable properties such as a negative refractive index. Most metamaterial designs have so far been based on resonant elements, such as split rings, and research has concentrated on microwave frequencies and above. Here, we present the first experimental realization of a non-resonant metamaterial designed to operate at zero frequency. Our samples are based on a recently proposed template for an anisotropic magnetic metamaterial consisting of an array of superconducting plates. Magnetometry experiments show a strong, adjustable diamagnetic response when a field is applied perpendicular to the plates. We have calculated the corresponding effective permeability, which agrees well with theoretical predictions. Applications for this metamaterial may include non-intrusive screening of weak d.c. magnetic fields.

Randomized trial of yoga in women with breast cancer undergoing radiation treatment

8505

Background: Yoga, an ancient Indian science, incorporates stress-reduction techniques that include regulated breathing, visual imagery, and meditation, as well as various postures that may be useful for cancer patients. Methods: A yoga program was developed that including loosening and breathing exercises, postures, alternate nostril breathing, a deep relaxation technique, and meditation for patients with breast cancer who were undergoing radiotherapy. Women participated in bi-weekly classes during their 6 weeks of radiation treatment. Sixty-one women with breast cancer were randomly assigned to either the yoga program or to a waitlist control group. Patients completed measures of intrusive thoughts and avoidance behaviors (Impact of Events Scale: IES), depressive symptoms (CES-D), sleep disturbances (Pittsburgh Sleep Quality Index), fatigue (BFI), and quality of life (SF-36) at baseline, 1 week, and 1 and 3 months after the last radiation therapy. We report on the outcomes 1 week after the end of radiotherapy. Results: The average age of the women was 52, 3% stage 0, 28% stage I, 43% stage II, and 26% stage III, 48% had undergone breast-conserving surgery, and 75% had received chemotherapy prior to starting radiotherapy. Analysis of covariance, controlling for baseline, revealed that the yoga group had significantly better SF-36 physical function scores (adjusted means: yoga 81.8 vs. control 68.6, P < 0.01), significantly higher SF-36 general health scores (adjusted means: yoga 78.3 vs. control 67.9, P < 0.03), marginally better SF-36 social functioning scores (adjusted means: yoga 85.3 vs. control 76.0, P > 0.1), significantly lower levels of sleep-related daytime dysfunction (adjusted means: yoga 0.5 vs. control 1.2, P < 0.04), and marginally lower levels of fatigue (adjusted means: yoga 1.9 vs. control 3.1, P < 0.06) than the control group. There were no other group differences on the SF-36 subscales or for the CES-D or IES scores. Conclusions: The results indicated that the yoga program was associated with statistically and clinical significant improvements in aspects of quality of life.

No significant financial relationships to disclose.