Sidelobe modeling and mitigation for a three mirror anastigmat cosmic microwave background telescope

Telescopes measuring cosmic microwave background (CMB) polarization on large angular scales require exquisite control of systematic errors to ensure the fidelity of the cosmological results. In particular, far-sidelobe contamination from wide angle scattering is a potentially prominent source of systematic error for large aperture microwave telescopes. Here we describe and demonstrate a ray-tracing-based modeling technique to predict far sidelobes for a three mirror anastigmat telescope designed to observe the CMB from the South Pole. Those sidelobes are produced by light scattered in the receiver optics subsequently interacting with the walls of the surrounding telescope enclosure. After comparing simulated sidelobe maps and angular power spectra for different enclosure wall treatments, we propose a highly scattering surface that would provide more than an order of magnitude reduction in the degree-scale far-sidelobe contrast compared to a typical reflective surface. We conclude by discussing the fabrication of a prototype scattering wall panel and presenting measurements of its angular scattering profile.

Incidence of cerebrovascular accident following head and neck free tissue transfer surgery

The aim of this study was to determine the incidence of postoperative cerebrovascular accident (CVA) following head and neck free tissue transfer and to identify predictive risk factors. A retrospective audit was performed of patients who underwent head and neck reconstructive surgery at Queen Elizabeth University Hospital between 2009 and 2020. The patient records were analysed to identify those who developed CVA within 30 days after surgery. A total of 1109 patients underwent head and neck free tissue transfer surgery, including 1048 neck dissection procedures. Of these, 78.6% had one or more identified risk factors for perioperative stroke. Five patients (0.45%) developed postoperative CVA. The results showed that CVA correlated to patients with hypercholesterolemia (P = 0.007). This study demonstrates the safety of free tissue transfer. Despite underlying co-morbidities and risk factors, the incidence of CVA is low following surgery and manipulation of the major vasculature of the neck.

Simons Observatory: characterizing the Large Aperture Telescope Receiver with radio holography

We present near-field radio holography measurements of the Simons Observatory Large Aperture Telescope Receiver optics. These measurements demonstrate that radio holography of complex millimeter-wave optical systems comprising cryogenic lenses, filters, and feed horns can provide detailed characterization of wave propagation before deployment. We used the measured amplitude and phase, at 4 K, of the receiver near-field beam pattern to predict two key performance parameters: 1) the amount of scattered light that will spill past the telescope to 300 K and 2) the beam pattern expected from the receiver when fielded on the telescope. These cryogenic measurements informed the removal of a filter, which led to improved optical efficiency and reduced sidelobes at the exit of the receiver. Holography measurements of this system suggest that the spilled power past the telescope mirrors will be less than 1%, and the main beam with its near sidelobes are consistent with the nominal telescope design. This is the first time such parameters have been confirmed in the lab prior to deployment of a new receiver. This approach is broadly applicable to millimeter and submillimeter instruments.

Simons Observatory: broadband metamaterial antireflection cuttings for large-aperture alumina optics

We present the design, fabrication, and measured performance of metamaterial antireflection cuttings (ARCs) for large-format alumina filters operating over more than an octave of bandwidth to be deployed at the Simons Observatory (SO). The ARC consists of subwavelength features diced into the optic's surface using a custom dicing saw with near-micrometer accuracy. The designs achieve percent-level control over reflections at angles of incidence up to 20^∘. The ARCs were demonstrated on four 42 cm diameter filters covering the 75 to 170 GHz band and a 50 mm diameter prototype covering the 200 to 300 GHz band. The reflection and transmission of these samples were measured using a broadband coherent source that covers frequencies from 20 GHz to 1.2 THz. These measurements demonstrate percent-level control over reflectance across the targeted pass-bands and a rapid reduction in transmission as the wavelength approaches the length scale of the metamaterial structure where scattering dominates the optical response. The latter behavior enables use of the metamaterial ARC as a scattering filter in this limit.

Simons Observatory HoloSim-ML: machine learning applied to the efficient analysis of radio holography measurements of complex optical systems

Near-field radio holography is a common method for measuring and aligning mirror surfaces for millimeter and sub-millimeter telescopes. In instruments with more than a single mirror, degeneracies arise in the holography measurement, requiring multiple measurements and new fitting methods. We present HoloSim-ML, a Python code for beam simulation and analysis of radio holography data from complex optical systems. This code uses machine learning to efficiently determine the position of hundreds of mirror adjusters on multiple mirrors with few micrometer accuracy. We apply this approach to the example of the Simons Observatory 6 m telescope.

Applying the British Association of Oral and Maxillofacial Surgeons quality outcomes metrics to a UK oncology and reconstructive surgery service - benchmarking the data

The British Association of Oral and Maxillofacial Surgery is soon to implement the Quality Outcomes in Oral in Maxillofacial Surgery (QOMS) to provide a platform for quality management across the specialty in the UK. The initial oncology and reconstruction audits for QOMS involves data collection on specific procedures and metrics. The aim of this report is to determine their appropriateness using extant audit datasets in our institution that overlap substantially with the QOMS audits. Pre-existing datasets comprising information on patients treated for oral cavity SCC with curative intent were analysed. Data on surgical margins, lymphadenectomy lymph node yield, delay between surgery and adjuvant radiotherapy, duration of hospital stay, and complications including flap failures were analysed. All statistical analyses were performed with SPSS 25. Run charts describing longitudinal data were generated using SPC for Excel version 6. Twenty three patients (3.1%) of 701 resections had a positive surgical margin reported. Seventeen (4.3%) of patients had less than 18 LNs in the ND specimen analysed. Mean time to start date of adjuvant therapy was 62 days. Only 9% of patients commenced adjuvant therapy within 6 weeks. The median duration of stay was 18 days. In 1153 free flaps a failure rate of 4.3% was identified. A total of 1349 complications (CD I-V) were recorded in the 1111 patients undergoing major surgery with free flap reconstruction. The QOMS selected metrics for oncology and reconstruction are clinically relevant, readily measurable, and likely to be actionable by the surgical team.

The Simons Observatory: metamaterial microwave absorber and its cryogenic applications

Controlling stray light at millimeter wavelengths requires special optical design and selection of absorptive materials that should be compatible with cryogenic operating environments. While a wide selection of absorptive materials exists, these typically exhibit high indices of refraction and reflect/scatter a significant fraction of light before absorption. For many lower index materials such as commercial microwave absorbers, their applications in cryogenic environments are challenging. In this paper, we present a new tool to control stray light: metamaterial microwave absorber tiles. These tiles comprise an outer metamaterial layer that approximates a lossy gradient index anti-reflection coating. They are fabricated via injection molding commercially available carbon-loaded polyurethane (25% by mass). The injection molding technology enables mass production at low cost. The design of these tiles is presented, along with thermal tests to 1 K. Room temperature optical measurements verify their control of reflectance to less than 1% up to 65^∘ angles of incidence, and control of wide angle scattering below 0.01%. The dielectric properties of the bulk carbon-loaded material used in the tiles is also measured at different temperatures, confirming that the material maintains similar dielectric properties down to 3 K.

Operative tactics in floor of mouth and tongue cancer resection - the importance of imaging and planning

Complete tumour resection (R0 margin) is an axiom of surgical oncology. Oral cancer ablation is challenging, due to anatomical, functional, and aesthetic considerations. R0 margin is strongly linked to better survival outcomes with great variation in the R0 % across units. This is commonly attributed to disease biology. Without disputing the importance of biological characteristics, we contend that image-based anatomical surgical planning has an important role to play in achieving complete resection. Here, we present our approach utilising cross-sectional imaging, anatomical characteristics and spatial awareness in planning resections for floor of mouth (FOM) and oral tongue cancers. We highlight the challenge of controlling the deep tumour margin lingual to mandible due to anterior vector constraints and emphasise the importance of resecting the genial muscles in a planned fashion and that any rim resection should be obliquely sagittal. In resecting lateral FOM tumours, assessing extension to the parapharyngeal fat is crucial; and mandibular rim resection at a sagittal plane below the mylohyoid line is often required. Assessing the proximity of the contralateral neurovascular pedicle, pre-epiglottic space and hyoid bone are crucial parameters to determine the extent of tongue tumour resection. Our cohort included 173 patients with FOM SCC and 299 patients with tongue SCC. Six patients (3.5%) from the FOM group and eight patients (3%) from the tongue group had involved (R1) margins following surgery. This was associated with local relapse (p<0.05). In conclusion, we demonstrate that image-based planning can aid achieving R0 resections and reduce disease relapse.

External validation of OroGrams as a predictive model for overall and progression-free survival in Scottish patients with oropharyngeal squamous cell carcinoma: a retrospective cohort study

The aims of this study were to externally validate the OroGrams (oropharyngeal cancer survival calculator) nomogram in a Scottish cohort with high endemic smoking rates, and to compare survival rates with the original validation cohort. A retrospective cohort study in Greater Glasgow and Clyde ENT and OMFS departments was performed to investigate survival outcomes of patients with oropharyngeal squamous cell carcinoma (OPSCC) from January 2012 - December 2017. The main outcome measures were progression-free (PFS) and overall survival (OS), and Kaplan Meier curves. The predictive accuracy of OroGrams was investigated for survival probabilities at one, three, and five years. Smoking and HPV-negative cancer rates were significantly higher in Scottish patients than in the UK consortium cohort. A greater proportion of Scottish patients had advanced UICC8 stages. PFS in patients with HPV-negative cancer appeared better in the Scottish cohort than in the original cohort. Calculated mean standardised Brier scores for PFS and OS were below 0.2 at all three follow-up points, suggesting good overall prognostic accuracy, but there was wide variation between predictive accuracy in individual patients. OroGrams shows prognostic accuracy at one-year follow up in Scotland. The accuracy decreases with longer follow-up periods.

Staging and treatment outcomes in oropharyngeal squamous cell carcinoma: a single-centre UK cohort

The 8^th edition of the UICC TNM (UICC 8) staging rules for oropharyngeal squamous cell carcinoma (OPSCC) acknowledges dichotomous disease biology based on the human papillomavirus (HPV) tumour status. This retrospective study was undertaken to validate those staging rules in a single UK treatment centre. Given a recent resurgence of interest in primary surgery for OPSCC, a secondary objective was to identify subsets of patients who might benefit. Patients presenting with OPSCC between 2010 and 2017 to the South Glasgow head and neck multidisciplinary team were identified from a prospective database. Only patients managed with curative intent were included (n=272). Stage group allocation according to the UICC 8 resulted in appropriate hazard discrimination, in contradistinction to the UICC 7 staging rules. Locally advanced (cT3-4) disease had a relatively poor prognosis irrespective of HPV status. No clear benefit for primary surgery in any subgroup was demonstrated. A dichotomous disease biology based on the HPV status of tumour is confirmed in this cohort. Patients with HPV-positive T1 and T2 primary tumours have an excellent prognosis when treated with non-surgical treatment regimens. The use of surgery as the primary management for categories of patients presenting with OPSCC should be in the context of clinical trials.

Broadband, millimeter-wave antireflection coatings for large-format, cryogenic aluminum oxide optics

We present two prescriptions for broadband ($ {\sim} 77 - 252\;{\rm GHz} $), millimeter-wave antireflection coatings for cryogenic, sintered polycrystalline aluminum oxide optics: one for large-format (700 mm diameter) planar and plano-convex elements, the other for densely packed arrays of quasi-optical elements-in our case, 5 mm diameter half-spheres (called "lenslets"). The coatings comprise three layers of commercially available, polytetrafluoroethylene-based, dielectric sheet material. The lenslet coating is molded to fit the 150 mm diameter arrays directly, while the large-diameter lenses are coated using a tiled approach. We review the fabrication processes for both prescriptions, then discuss laboratory measurements of their transmittance and reflectance. In addition, we present the inferred refractive indices and loss tangents for the coating materials and the aluminum oxide substrate. We find that at 150 GHz and 300 K the large-format coating sample achieves $ (97 \pm 2)\% $ transmittance, and the lenslet coating sample achieves $ (94 \pm 3)\% $ transmittance.

Shape of (101955) Bennu indicative of a rubble pile with internal stiffness

The shapes of asteroids reflect interplay between their interior properties and the processes responsible for their formation and evolution as they journey through the Solar System. Prior to the OSIRIS-REx (Origins, Spectral Interpretation, Resource Identification, and Security-Regolith Explorer) mission, Earth-based radar imaging gave an overview of (101955) Bennu's shape. Here, we construct a high-resolution shape model from OSIRIS-REx images. We find that Bennu's top-like shape, considerable macroporosity, and prominent surface boulders suggest that it is a rubble pile. High-standing, north-south ridges that extend from pole to pole, many long grooves, and surface mass wasting indicate some low levels of internal friction and/or cohesion. Our shape model indicates that, similar to other top-shaped asteroids, Bennu formed by reaccumulation and underwent past periods of fast spin leading to its current shape. Today, Bennu might follow a different evolutionary pathway, with interior stiffness permitting surface cracking and mass wasting.

CC chemokine receptor 2 promotes recruitment of myeloid cells associated with insulin resistance in nonalcoholic fatty liver disease

Nonalcoholic fatty liver disease (NAFLD) is a common disease, closely associated with obesity and insulin resistance. We investigated the presence of a subset of myeloid cells associated with metabolic disturbance in the liver of patients with NAFLD and a murine model of obesity-induced liver disease. Gene and protein expression in liver and serum was investigated with RT-PCR or ELISA and correlated to clinical disease. Liver-infiltrating immune cells were isolated from normal or diseased human liver for flow cytometric analysis. In animal experiments, mice were fed a high-fat diet (60% of calories from fat) for 16 wk, or high-fat diet with 30% fructose for 32 wk to induce steatohepatitis and fibrosis. A small molecule inhibitor of CC chemokine receptor 2 (CCR2), CCX872, was administered to some mice. A subset of CD11c⁺CD206⁺ immune cells was enriched in human liver tissue, and greater infiltration was observed in NAFLD. The presence of CD11c⁺CD206⁺ myeloid cells correlated with systemic insulin resistance. CD11c⁺CD206⁺ cells expressed high levels of CCR2, and liver CC chemokine ligand 2 (CCL2) expression was increased in nonalcoholic steatohepatitis and correlated with disease activity. In mice, CCR2 inhibition reduced infiltration of liver CD11b⁺CD11c⁺F4/80⁺ monocytes, which are functional homologs of human CD11c⁺CD206⁺ cells, and improved liver injury and glycemic control. A role for CCR2/CCL2 in human NAFLD has long been postulated. These data confirm a role for this chemokine/receptor axis, through mediating adipose and hepatic infiltration of myeloid cells. Inhibition of CCR2 improved hepatic inflammation and fibrosis in murine models of NAFLD. These data confirm the rationale for targeting CCR2 to treat NAFLD. NEW & NOTEWORTHY These data show for the first time that CD11c⁺CD206⁺ myeloid cells, previously associated with human adipose tissue inflammation, infiltrate into liver tissue in nonalcoholic fatty liver disease. These cells express CCR2. Inhibition of CCR2 in mice inhibits hepatic inflammation caused by a murine homolog of these myeloid cells and improves experimental liver disease.

Sentinel lymph node biopsy for oral squamous cell carcinoma. Where are we now?

Recent data have confirmed that elective surgical management of the cN0 neck improves survival in patients with early (T1-T2) oral squamous cell carcinoma (SCC), and is better than watchful waiting. However, elective neck dissection (END) may not always be necessary. Sentinel node biopsy (SNB), which is a reliable staging test for patients with early disease and a radiologically N0 neck, can detect occult metastases with a sensitivity of 86%-94%. Patients with no sign of metastases on SNB could avoid neck dissection, and individual treatment should reduce both morbidity and cost. Currently, SNB for oral SCC is available at a limited number of centres in the UK, but this is likely to change as national guidelines have recommended that it is incorporated into the standard treatment pathway. It is therefore important to understand the current evidence that supports its use, its limitations and related controversies, and to plan for a validated training programme.

Abstract 5655: Inhibition of CCR2 potentiates checkpoint inhibitor immunotherapy in murine model of pancreatic cancer

Pancreatic cancer is an aggressive malignancy with a 5 year survival rate of less than five percent. The predominant immune cells infiltrating the tumor microenvironment are monocytes/macrophages, which are reported to support tumor growth by suppressing host immune responses to the tumor. Recruitment of monocytes to various tissues, including tumors, is dependent upon activation of the chemokine receptor CCR2 by one or more of the chemokines CCL2, CCL8 and CCL13. In preclinical and clinical studies, inhibition of CCR2 in pancreatic cancer has shown to decrease tumor progression by blocking recruitment and accumulation of monocytes/macrophages in the tumor microenvironment. Analysis of human pancreatic tumors revealed elevation of both CCL2 and CSF1, which recruit monocytes, as well as the monocyte marker CD14, in advanced pancreatic cancers. Current immunotherapy using checkpoint inhibitors are effective in some tumors, but lack efficacy in immune insensitive cancers, including pancreatic cancer. Here, we report that the inhibition of CCR2 using a small molecule antagonist potentiates anti-PD-1 immunotherapy in a syngeneic, orthotropic mouse model of pancreatic cancer. Our data reveal that blocking CCR2 decreases tumor burden by blocking monocyte infiltration and creating a microenvironment more favorable for CD8 T cells activity, and provide a mechanistic rationale for investigating the combination of a CCR2 antagonist and an immune checkpoint inhibitor in pancreatic cancer.

Citation Format: Christine Janson, Heiyoun Jung, Linda Ertl, Shirley Liu, Ton Dang, Yibin Zeng, Antoni Krasinski, Jeff McMahon, Penglie Zhang, Israel Charo, Rajinder Singh, Thomas J. Schall. Inhibition of CCR2 potentiates checkpoint inhibitor immunotherapy in murine model of pancreatic cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 5655. doi:10.1158/1538-7445.AM2017-5655

A longitudinal cohort study of HIV 'treatment as prevention' in gay, bisexual and other men who have sex with men: the Treatment with Antiretrovirals and their Impact on Positive And Negative men (TAIPAN) study protocol

BACKGROUND

Australia has increased coverage of antiretroviral treatment (ART) over the past decade, reaching 73% uptake in 2014. While ART reduces AIDS-related deaths, accumulating evidence suggests that it could also bolster prevention efforts by reducing the risk of HIV transmission ('treatment as prevention'). While promising, evidence of community-level impact of treatment as prevention on reducing HIV incidence among gay and bisexual men is limited. We describe a study protocol that aims to determine if scale up of testing and treatment for HIV leads to a reduction in community viraemia and, in turn, if this reduction is temporally associated with a reduction in HIV incidence among gay and bisexual men in Australia's two most populous states.

METHODS

Over the period 2009 to 2017, we will establish two cohorts making use of clinical and laboratory data electronically extracted retrospectively and prospectively from 73 health services and laboratories in the states of New South Wales and Victoria. The 'positive cohort' will consist of approximately 13,000 gay and bisexual men (>90% of all people living with HIV). The 'negative cohort' will consist of at least 40,000 HIV-negative gay and bisexual men (approximately half of the total population). Within the negative cohort we will use standard repeat-testing methods to calculate annual HIV incidence. Community prevalence of viraemia will be defined as the proportion of men with a viral load ≥200RNA copies/mm³, which will combine viral load data from the positive cohort and viraemia estimates among those with an undiagnosed HIV infection. Using regression analyses and adjusting for behavioural and demographic factors associated with infection, we will assess the temporal association between the community prevalence of viraemia and the incidence of HIV infection. Further analyses will make use of these cohorts to assess incidence and predictors of treatment initiation, repeat HIV testing, and viral suppression.

DISCUSSION

This study will provide important information on whether 'treatment as prevention' is associated with a reduction in HIV incidence at a community level among gay and bisexual men.

Experiences of care by Australians with a diagnosis of borderline personality disorder

Borderline personality disorder (BPD) is a complex and challenging mental health condition for the person and service providers who support them. This paper reports on the results of a survey of 153 people with a diagnosis of BPD about their experiences of attempting to receive support in managing this mental health condition. It provides their perceptions of a range of experiences not reported in the existing literature, including general practitioner roles, urban and rural differences, public and private hospital differences, and comparison of usefulness of support across multiple support types. People with a diagnosis of BPD continue to experience significant discrimination when attempting to get their needs met within both public and private health services. Further education for nurses and other health professionals is indicated to address pervasive negative attitudes towards people with a diagnosis of BPD. There is limited understanding of the experience of seeking and receiving treatment and care by people with a diagnosis of borderline personality disorder (BPD), their perceptions of barriers to care and the quality of services they receive. This study aimed to explore these experiences from the perspective of Australians with this diagnosis. An invitation to participate in an online survey was distributed across multiple consumer and carer organizations and mental health services, by the Private Mental Health Consumer Carer Network (Australia) in 2011. Responses from 153 people with a diagnosis of BPD showed that they experience significant challenges and discrimination when attempting to get their needs met within both public and private health services, including general practice. Seeking help from hospital emergency departments during crises was particularly challenging. Metropolitan and rural differences, and gender differences, were also apparent. Community supports were perceived as inadequate to meet their needs. This study provides data on a range of experiences not reported in existing literature, including general practitioner roles, urban and rural differences, public and private hospital differences, and comparison of usefulness of support across multiple support types. Its findings can help inform better training for health professionals and better care for this population.

Experiences of family carers of people diagnosed with borderline personality disorder

There is limited understanding of the experience of family carers of people diagnosed with borderline personality disorder (BPD). This study aimed to explore their experiences of being carers, their attempts to seek help for the person diagnosed with BPD and their own carer needs. An invitation to participate in an online survey was distributed to carers across multiple consumer and carer organizations and mental health services, by the Private Mental Health Consumer Carer Network (Australia) in 2011. Responses from 121 carers showed that they experience significant challenges and discrimination when attempting to engage with and seek support from health services. Comparison with consumers' experiences (reported elsewhere) showed that these carers have a clear understanding of the discrimination faced by people with this diagnosis, largely because they also experience exclusion and discrimination. Community carer support services were perceived as inadequate. General practitioners were an important source of support; however, they and other service providers need more education and training to support attitudinal change to address discrimination, recognize carers' needs and provide more effective support. This study provides the first detailed account of BPD carers' experiences across a broad range of support needs and interactions with community support and health services.

Evidence of lensing of the cosmic microwave background by dark matter halos

We present evidence of the gravitational lensing of the cosmic microwave background by 10(13) solar mass dark matter halos. Lensing convergence maps from the Atacama Cosmology Telescope Polarimeter (ACTPol) are stacked at the positions of around 12 000 optically selected CMASS galaxies from the SDSS-III/BOSS survey. The mean lensing signal is consistent with simulated dark matter halo profiles and is favored over a null signal at 3.2σ significance. This result demonstrates the potential of microwave background lensing to probe the dark matter distribution in galaxy group and galaxy cluster halos.

Rapamycin attenuates aggressive behavior in a rat model of pilocarpine-induced epilepsy

Psychiatric disorders are fairly common comorbidities of epilepsy in humans. Following pilocarpine-induced status epilepticus (SE), experimental animals not only developed spontaneous recurrent seizures, but also exhibited significantly elevated levels of aggressive behavior. The cellular and molecular mechanism triggering these behavioral alterations remains unclear. In the present study, we found that aggression is positively correlated with development of spontaneous seizures. Treatment with rapamycin, a potent mTOR (mammalian target of rapamycin pathway)-pathway inhibitor, markedly diminished aggressive behavior. Therefore, the mTOR pathway may have significance in the underlying molecular mechanism leading to aggression associated with epilepsy.

A prospective clinical trial of cholecalciferol 2000 IU/day in colorectal cancer patients: evidence of a chemotherapy-response interaction

BACKGROUND

We have previously reported a negative correlation between the effect of chemotherapy and 25-hydroxy vitamin D(3) (25-D(3)) levels in patients with colorectal cancer. Based on this finding, we hypothesized that the response to vitamin D(3) supplementation may be attenuated in patients with colorectal cancer.

AIM

To determine 25-D(3) response to 2000 IU/day vitamin D(3) supplementation in patients with colorectal cancer.

MATERIALS AND METHODS

Fifty evaluable colorectal cancer patients were treated with vitamin D(3) at 2000 IU/day for 6 months. Serum 25-D(3) levels were measured at baseline, 3, and 6 months of supplementation.

RESULTS

The mean 25-D(3) level was 17.5 ng/ml at baseline, 31.6 ng/ml at 3 months, and 33.8 ng/ml at 6 months. The most important factor in determining 25-D(3) response was chemotherapy status. A rise in 25-D(3) of ≥10 ng/ml at the 3-month interval was observed in 92% of chemotherapy-free patients vs. 39% of chemotherapy patients. Similar differences in response were noted at the 6-month interval.

CONCLUSION

Depressed 25-D(3) levels are common in patients with colorectal cancer. Active chemotherapy is associated with an attenuated response to 2000 IU of D(3) supplementation in this patient population. Alternative vitamin D(3) dosing schedules need further investigation in colorectal cancer patients undergoing chemotherapy.