Citations

OBJECTIVE The authors have observed that a subset of patients referred for evaluation of peroneal neuropathy with “negative” findings on MRI of the knee have subtle evidence of a peroneal intraneural ganglion cyst on subsequent closer inspection. The objective of this study was to introduce the nearly invisible peroneal intraneural ganglion cyst and provide illustrative cases. The authors further wanted to identify clues to the presence of a nearly invisible cyst. METHODS Illustrative cases demonstrating nearly invisible peroneal intraneural ganglion cysts were retrospectively reviewed and are presented. Case history and physical examination, imaging, and intraoperative findings were reviewed for each case. The outcomes of interest were the size and configuration of peroneal intraneural ganglion cysts over time, relative to various interventions that were performed, and in relation to physical examination and electrodiagnostic findings. RESULTS The authors present a series of cases that highlight the dynamic nature of peroneal intraneural ganglion cysts and introduce the nearly invisible cyst as a new and emerging part of the spectrum. The cases demonstrate changes in size and morphology over time of both the intraneural and extraneural compartments of these cysts. Despite “negative” MR imaging findings, nearly invisible cysts can be identified in a subset of patients. CONCLUSIONS The authors demonstrate here that peroneal intraneural ganglion cysts ride a roller coaster of change in both size and morphology over time, and they describe the nearly invisible cyst as one end of the spectrum. They identified clues to the presence of a nearly invisible cyst, including deep peroneal predominant symptoms, fluctuating symptoms, denervation changes in the tibialis anterior muscle, and abnormalities of the superior tibiofibular joint, and they correlate the subtle imaging findings to the internal fascicular topography of the common peroneal nerve. The description of the nearly invisible cyst may allow for increased recognition of this pathological entity that occurs with a spectrum of findings.

Surgical transection of sensory nerves in the treatment of intractable neuropathic pain is a commonly performed procedure. At times these cases can be particularly challenging when encountering obese patients, when targeting deeper nerves or those with a variable branching pattern, or in the case of repeat operations. In this case series, the authors describe their experience with ultrasound-guided surgical instrument placement during transection of a saphenous nerve in the region of prior vascular surgery in 1 patient and in the lateral femoral cutaneous nerve in 2 obese patients. The authors also describe this novel technique and provide pilot data that suggests ultrasound-assisted surgery may allow for complex cases to be completed in an expedited fashion through smaller incisions.

522 Background: Metformin inhibits mTOR and downstream pathways involved in cell proliferation and survival by inducing AMPK activation. Although its use has been associated with decreased risk of colorectal cancer (CRC), the effect of metformin on cancer related mortality is unclear. We performed a meta-analysis of published observational studies evaluating metformin use in patients with CRC and its association with overall and CRC-specific survival. Methods: Through a systematic search of PubMed and conference presentations (cut-off: August 2013), we identified 8 observational studies (18,537 total patients with CRC; 6242 CRC patients with DM) reporting the association between metformin use and survival after diagnosis of CRC. Summary hazard ratio (HR) with 95% confidence intervals (CI) was estimated using the random effects model, and heterogeneity was measured using the inconsistency index (I2). Results: On meta-analysis, metformin use was associated with a 34% reduction in mortality in CRC patients as compared to non-use (adjusted HR, 0.66; 95% CI, 0.54-0.81), albeit with high heterogeneity (I2=66.9%). After exclusion of one study, which contributed to considerable heterogeneity, a 28% reduction in mortality was considered a more conservative, consistent effect estimate (adjusted HR, 0.72; 95% CI, 0.64-0.81), with minimal heterogeneity (I2=16.2%). On restricting analysis only to patients with DM, use of metformin (vs non-use) was associated with decreased all-cause mortality (6 studies; adjusted HR, 0.63; 95% CI, 0.49-0.81) and CRC-specific mortality (3 studies; adjusted HR, 0.66; 95% CI, 0.50-0.87). Conclusions: Based on meta-analysis of observational studies, the use of metformin in diabetic patients with CRC appears to be associated with reduced all-cause mortality and CRC-specific mortality. Further prospective investigation of metformin’s effect on outcome in CRC patients is warranted.

187 Background: Patient-reported evaluations of interpersonal quality of care are essential elements of quality of cancer care assessment. At times, patients may be unable to report themselves on their care experience and systems may rely on proxy reports. The validity of this approach is dependent on the degree to which family caregiver assessments are concordant with patient assessments. Methods: A VA cohort of colorectal cancer (CRC) patients and their caregivers both completed a self-administered questionnaire on the quality of VA cancer care in 3 specific domains: surgery, chemotherapy overall and chemotherapy nursing care, all measured on a 5-point Likert scale. Because the kappa statistic penalizes skewed distributions which are commonly seen in patient satisfaction reports, agreement between patients and caregivers on perceptions of quality care were measured using Gwet’s AC2 statistic. Stratified analyses on caregiver burden, race, education, and age as well as patient’s stage of disease were used to assess variation in agreement. Results: 417 caregiver-patient dyads completed the survey (70% response rate), of whom 362 (86.8%) had surgery and 195 (46.8%) had chemotherapy. Overall agreement was high for the 3 quality of care domains: AC2 (95% CI): 0.870 (0.838, 0.903) for surgery, 0.835 (0.786, 0.884) for chemotherapy overall and 0.906 (0.868, 0.944) for chemotherapy nurses. Stratified analyses of agreement showed particular populations of higher or lower agreement; however the findings were inconsistent across the three domains and most were not statistically significant. Patients with lower stage (I-II) had higher agreement than higher stages (III-IV) (AC2: 0.967 and 0.879 respectively, P = 0.006) but only in the chemotherapy nurses domain. For the surgery domain, age was the only significant difference in agreement (0.816, 0.912, and 0.838 for < 50, 51-65, and > 65 respectively, P = 0.03). Conclusions: Family caregiver reports on the quality of CRC care were highly concordant with patient reports. Therefore, family caregivers may be able to provide reasonable proxy report on measures of quality of cancer care when patient reports are unavailable.

311 Background: Previous population-based studies have shown variations in disease incidence and overall survival (OS) among multiple myeloma (MM) patients (pts) from different ethnic and racial backgrounds. However, the impact of race and ethnicity on early mortality (EM) or death in the first year after the diagnosis of MM is less well known. Methods: Pts with MM diagnosed from 2000-2011 were identified in the NCDB. We obtained data associated with socio-demographics, type and location of care facility, as well as the use of autologous stem cell transplant (ASCT) as an initial treatment option. Two cohorts were created based on the use of ASCT: 1) The group who received an upfront ASCT and 2) Pts who were 75 years or older who are unlikely to have ever received an ASCT. The rate of early mortality (EM) was estimated using the 1-year OS and assessed for all pts based on racial/ethnic background and the use of ASCT in their therapy. Results: There were a total of 108,352 pts who were included in this analysis. The median age of this cohort was 65 years (Range: 20 – 90). Of these 58,223 (54%) were male. The racial distributions of these cohorts were as follows: 78,589 (73%) White non-Hispanic (WNH), 21,292 (20%) Black non-Hispanic (BNH), 1,943 (2%) Asian Pacific-Islander (API), 293 (< 1%) Native-American (NA) and 6,235 (5%) Hispanics-any race (HIS). The estimated 1-yr OS (95% CI) was 71% (71 – 72) for WNH, 74% (73 – 74) for BNH, 77% (75 – 79) for API, 73% (68 – 78) for NA and 75% (74 – 76) for HIS. Amongst patients who received an upfront ASCT, the estimated 1-yr OS (95% CI) was 97% (97 – 98) for WNH (Reference), 98% (97 – 98) for BNH (P = 0.99), 99% (99 – 100) for API (P = 0.96) and 98% (97 – 99) for HIS (P = 0.99). Whereas amongst pts who likely never received an ASCT (75 years or older), the estimated 1-yr OS (95% CI) was 55% (54 – 56) WNH (Reference), 57% (56 – 59) for BNH (P = 0.03), 62% (58 – 67) for API (P = 0.02), 55% (43 – 72) for NA (P = 0.99) and 55% (52 – 58) for HIS (P = 0.99). Conclusions: In general, WNHs have a worse 1-yr OS compared to BNH and API. However, this disparity appears significant only among pts unlikely to get an ASCT. Further studies are required to identify explanations for such disparate outcomes based on race and use of ASCT.

226 Background: Patients undergoing cancer treatment often need support from an informal caregiver to help manage symptoms. Self-efficacy (SE) in caregiving refers to confidence in being able to care for the patient’s needs. Low SE has been associated with increased caregiver burden and mental health symptoms, which in turn, can affect the quality of informal care provided. The objective of this study was to examine the relationship between caregiver training received from cancer care providers and SE in caregivers of patients with colorectal cancer (CRC). Methods: Caregivers of CRC patients diagnosed in 2009 were invited to complete a self-administered questionnaire. Caregivers were asked about specific patient problems (pain, bowel, fatigue, medications, and other). Caregiver perceptions of training adequacy and SE were assessed on a problem specific basis. The patient’s stage of disease was obtained from cancer registry data. Associations between training and SE were examined for each problem using multivariate logistic regression and adjusted for age, relationship to patient, race, care burden, level of education, stage of disease, perception of patient’s health, and general confidence as a caregiver. Results: 417 caregivers completed the survey (70% response rate), of whom 374 (90%) were female and 284 (68%) were the patient’s spouse/partner. The number of caregivers reporting inadequate training for CRC-related problems were pain 77 (38%), bowel 80 (38%), fatigue 121 (48%), medication 65 (26%), and other 101 (40%). The odds of having low SE were significantly higher among those with perceptions of inadequate training across the following CRC-related problems: pain, 10.10 (3.36, 30.39); bowel, 5.04 (1.98, 12.82); fatigue, 8.45 (3.22, 22.15); managing medications, 9.00 (3.30, 24.51); and other, 3.87 (1.68, 8.93). Conclusions: This study showed a significant association between caregiver training and SE in a cross-sectional study. Given that the perception of inadequate training among caregivers was common, further exploration of the longitudinal impact of training on caregiver SE should be done to identify interventions to help improve the experience of cancer caregivers.

659 Background: Prospective survival prediction of patients with metastatic colorectal cancer is difficult. Prognosis estimation based on readily available clinicopathologic factors has the potential to inform clinical practice and improve risk stratification for clinical trials. We constructed prognostic nomograms for OS and PFS in mCRC using the multi-trial ARCAD database. Methods: Data from 19,678 mCRC pts accrued to 24 first line randomized phase III clinical trials since 1997 were used to construct and validate Cox models for PFS and OS, stratified by treatment arm within each study. Candidate variables included age, gender, BMI, performance status, colon vs. rectal cancer, prior chemotherapy, number of metastatic sites, sites of metastases (liver, lung, lymph nodes), and baseline bilirubin, albumin, white blood cell count, hemoglobin, platelets, absolute neutrophil count, and derived neutrophil:lymphocyte ratio (dNLR). Missing data (<11%) were imputed, continuous variables modeled with splines, and clinically relevant pairwise interactions considered if p<0.001. Final models were internally validated via bootstrapping to obtain optimism-corrected calibration and discrimination C-indices, and externally validated using a 10% holdout sample from each trial. Results: Nomograms for OS and PFS including remaining variables were well calibrated with C-indices of 0.66 and 0.60, respectively. Evaluation of external validity revealed good concordance; 71% and 67% respectively between predicted (> vs. <50% probability) and actual (yes/no) 1-year OS and 6-month PFS, and median 1-year OS and 6-month PFS predictions fell within the actual 95% Kaplan-Meier intervals. Gender, liver and lung metastases, and dNLR were not prognostic for OS; prior chemo, colon vs. rectum, dNLR, liver and lymph node metastases, and gender did not predict for PFS. No clinically relevant pairwise interactions were identified. Conclusions: The proposed nomograms are well calibrated and internally and externally valid. These tools have the potential to aid prognostication and patient/physician communication, and balance risk in randomized trials in mCRC.