Cancer Risks Associated With TP53 Pathogenic Variants: Maximum Likelihood Analysis of Extended Pedigrees for Diagnosis of First Cancers Beyond the Li-Fraumeni Syndrome Spectrum.

PURPOSE: Establishing accurate age-related penetrance figures for the broad range of cancer types that occur in individuals harboring a pathogenic germline variant in the TP53 gene is essential to determine the most effective clinical management strategies. These figures also permit optimal use of cosegregation data for classification of TP53 variants of unknown significance. Penetrance estimation can easily be affected by bias from ascertainment criteria, an issue not commonly addressed by previous studies. MATERIALS AND METHODS: We performed a maximum likelihood penetrance estimation using full pedigree data from a multicenter study of 146 TP53-positive families, incorporating adjustment for the effect of ascertainment and population-specific background cancer risks. The analysis included pedigrees from Australia, Spain, and United States, with phenotypic information for 4,028 individuals. RESULTS: Core Li-Fraumeni syndrome (LFS) cancers (breast cancer, adrenocortical carcinoma, brain cancer, osteosarcoma, and soft tissue sarcoma) had the highest hazard ratios of all cancers analyzed in this study. The analysis also detected a significantly increased lifetime risk for a range of cancers not previously formally associated with TP53 pathogenic variant status, including colorectal, gastric, lung, pancreatic, and ovarian cancers. The cumulative risk of any cancer type by age 50 years was 92.4% (95% CI, 82.2 to 98.3) for females and 59.7% (95% CI, 39.9 to 81.3) for males. Females had a 63.3% (95% CI, 35.6 to 90.1) cumulative risk of developing breast cancer by age 50 years. CONCLUSION: The results from maximum likelihood analysis confirm the known high lifetime risk for the core LFS-associated cancer types providing new risk estimates and indicate significantly increased lifetime risks for several additional cancer types. Accurate cancer risk estimates will help refine clinical recommendations for TP53 pathogenic variant carriers and improve TP53 variant classification.

DNA Mismatch Repair Gene Variant Classification: Evaluating the Utility of Somatic Mutations and Mismatch Repair Deficient Colonic Crypts and Endometrial Glands.

Germline pathogenic variants in the DNA mismatch repair (MMR) genes (Lynch syndrome) predispose to colorectal (CRC) and endometrial (EC) cancer. Lynch syndrome specific tumor features were evaluated for their ability to support the ACMG/InSiGHT framework in classifying variants of uncertain clinical significance (VUS) in the MMR genes. Twenty-eight CRC or EC tumors from 25 VUS carriers (6xMLH1, 9xMSH2, 6xMSH6, 4xPMS2), underwent targeted tumor sequencing for the presence of microsatellite instability/MMR-deficiency (MSI-H/dMMR) status and identification of a somatic MMR mutation (second hit). Immunohistochemical testing for the presence of dMMR crypts/glands in normal tissue was also performed. The ACMG/InSiGHT framework reclassified 7/25 (28%) VUS to likely pathogenic (LP), three (12%) to benign/likely benign, and 15 (60%) VUS remained unchanged. For the seven re-classified LP variants comprising nine tumors, tumor sequencing confirmed MSI-H/dMMR (8/9, 88.9%) and a second hit (7/9, 77.8%). Of these LP reclassified variants where normal tissue was available, the presence of a dMMR crypt/gland was found in 2/4 (50%). Furthermore, a dMMR endometrial gland in a carrier of an MSH2 exon 1-6 duplication provides further support for an upgrade of this VUS to LP. Our study confirmed that identifying these Lynch syndrome features can improve MMR variant classification, enabling optimal clinical care.

The clinical utility and costs of whole-genome sequencing to detect cancer susceptibility variants-a multi-site prospective cohort study.

BACKGROUND: Many families and individuals do not meet criteria for a known hereditary cancer syndrome but display unusual clusters of cancers. These families may carry pathogenic variants in cancer predisposition genes and be at higher risk for developing cancer. METHODS: This multi-centre prospective study recruited 195 cancer-affected participants suspected to have a hereditary cancer syndrome for whom previous clinical targeted genetic testing was either not informative or not available. To identify pathogenic disease-causing variants explaining participant presentation, germline whole-genome sequencing (WGS) and a comprehensive cancer virtual gene panel analysis were undertaken. RESULTS: Pathogenic variants consistent with the presenting cancer(s) were identified in 5.1% (10/195) of participants and pathogenic variants considered secondary findings with potential risk management implications were identified in another 9.7% (19/195) of participants. Health economic analysis estimated the marginal cost per case with an actionable variant was significantly lower for upfront WGS with virtual panel ($8744AUD) compared to standard testing followed by WGS ($24,894AUD). Financial analysis suggests that national adoption of diagnostic WGS testing would require a ninefold increase in government annual expenditure compared to conventional testing. CONCLUSIONS: These findings make a case for replacing conventional testing with WGS to deliver clinically important benefits for cancer patients and families. The uptake of such an approach will depend on the perspectives of different payers on affordability.

A tumor focused approach to resolving the etiology of DNA mismatch repair deficient tumors classified as suspected Lynch syndrome.

Routine screening of tumors for DNA mismatch repair (MMR) deficiency (dMMR) in colorectal (CRC), endometrial (EC) and sebaceous skin (SST) tumors leads to a significant proportion of unresolved cases classified as suspected Lynch syndrome (SLS). SLS cases (n = 135) were recruited from Family Cancer Clinics across Australia and New Zealand. Targeted panel sequencing was performed on tumor (n = 137; 80×CRCs, 33×ECs and 24xSSTs) and matched blood-derived DNA to assess for microsatellite instability status, tumor mutation burden, COSMIC tumor mutational signatures and to identify germline and somatic MMR gene variants. MMR immunohistochemistry (IHC) and MLH1 promoter methylation were repeated. In total, 86.9% of the 137 SLS tumors could be resolved into established subtypes. For 22.6% of these resolved SLS cases, primary MLH1 epimutations (2.2%) as well as previously undetected germline MMR pathogenic variants (1.5%), tumor MLH1 methylation (13.1%) or false positive dMMR IHC (5.8%) results were identified. Double somatic MMR gene mutations were the major cause of dMMR identified across each tumor type (73.9% of resolved cases, 64.2% overall, 70% of CRC, 45.5% of ECs and 70.8% of SSTs). The unresolved SLS tumors (13.1%) comprised tumors with only a single somatic (7.3%) or no somatic (5.8%) MMR gene mutations. A tumor-focused testing approach reclassified 86.9% of SLS into Lynch syndrome, sporadic dMMR or MMR-proficient cases. These findings support the incorporation of tumor sequencing and alternate MLH1 methylation assays into clinical diagnostics to reduce the number of SLS patients and provide more appropriate surveillance and screening recommendations.

A tumor focused approach to resolving the etiology of DNA mismatch repair deficient tumors classified as suspected Lynch syndrome.

Routine screening of tumors for DNA mismatch repair (MMR) deficiency (dMMR) in colorectal (CRC), endometrial (EC) and sebaceous skin (SST) tumors leads to a significant proportion of unresolved cases classified as suspected Lynch syndrome (SLS). SLS cases (n=135) were recruited from Family Cancer Clinics across Australia and New Zealand. Targeted panel sequencing was performed on tumor (n=137; 80xCRCs, 33xECs and 24xSSTs) and matched blood-derived DNA to assess for microsatellite instability status, tumor mutation burden, COSMIC tumor mutational signatures and to identify germline and somatic MMR gene variants. MMR immunohistochemistry (IHC) and MLH1 promoter methylation were repeated. In total, 86.9% of the 137 SLS tumors could be resolved into established subtypes. For 22.6% of these resolved SLS cases, primary MLH1 epimutations (2.2%) as well as previously undetected germline MMR pathogenic variants (1.5%), tumor MLH1 methylation (13.1%) or false positive dMMR IHC (5.8%) results were identified. Double somatic MMR gene mutations were the major cause of dMMR identified across each tumor type (73.9% of resolved cases, 64.2% overall, 70% of CRC, 45.5% of ECs and 70.8% of SSTs). The unresolved SLS tumors (13.1%) comprised tumors with only a single somatic (7.3%) or no somatic (5.8%) MMR gene mutations. A tumor-focused testing approach reclassified 86.9% of SLS into Lynch syndrome, sporadic dMMR or MMR-proficient cases. These findings support the incorporation of tumor sequencing and alternate MLH1 methylation assays into clinical diagnostics to reduce the number of SLS patients and provide more appropriate surveillance and screening recommendations.

Use and outcomes from neoadjuvant chemotherapy in borderline resectable pancreatic ductal adenocarcinoma in an Australasian population.

BACKGROUND: Use of neoadjuvant (NA) chemotherapy is recommended when pancreatic ductal adenocarcinoma (PDAC) is borderline resectable METHOD: A retrospective analysis of consecutive patients with localized PDAC between January 2016 and March 2019 within the Australasian Pancreatic Cancer Registry (PURPLE, Pancreatic cancer: Understanding Routine Practice and Lifting End results) was performed. Clinicopathological characteristics, treatment, and outcome were analyzed. Overall survival (OS) comparison was performed using log-rank model and Kaplan-Meier analysis. RESULTS: The PURPLE database included 754 cases with localised PDAC, including 148 (20%) cases with borderline resectable pancreatic cancer (BRPC). Of the 148 BRPC patients, 44 (30%) underwent immediate surgery, 80 (54%) received NA chemotherapy, and 24 (16%) were inoperable. The median age of NA therapy patients was 63 years and FOLFIRINOX (53%) was more often used as NA therapy than gemcitabine/nab-paclitaxel (31%). Patients who received FOLFIRINOX were younger than those who received gemcitabine/nab-paclitaxel (60 years vs. 67 years, p = .01). Surgery was performed in 54% (43 of 80) of BRPC patients receiving NA chemotherapy, with 53% (16 of 30) achieving R0 resections. BRPC patients undergoing surgery had a median OS of 30 months, and 38% (9 of 24) achieved R0 resection. NA chemotherapy patients had a median OS of 20 months, improving to 24 months versus 10 months for patients receiving FOLFIRINOX compared to gemcitabine/nab-paclitaxel (Hazard Ratio (HR) .3, p < .0001). CONCLUSIONS: NA chemotherapy use in BRPC is increasing in Australia. One half of patients receiving NA chemotherapy proceed to curative resection, with 53% achieving R0 resections. Patients receiving Infusional 5-flurouracil, Irinotecan and Oxaliplatin (FOLIRINOX) had increased survival than gemcitabine/nab-paclitaxel. Treatment strategies are being explored in the MASTERPLAN and DYNAMIC-Pancreas trials.

KRAS G12D Mutation Subtype in Pancreatic Ductal Adenocarcinoma: Does It Influence Prognosis or Stage of Disease at Presentation?

Background: KRAS G12D mutation subtype is present in over 40% of pancreatic ductal adenocarcinoma (PDAC), one of the leading global causes of cancer death. This retrospective cohort study aims to investigate whether detection of the KRAS G12D mutation subtype in PDAC patients is a determinant of prognosis across all stages of disease. Methods: We reviewed the medical records of 231 patients presenting with PDAC at a large tertiary hospital, and compared survival using the Kaplan Meier, log-rank test and Cox proportional hazards regression model. Results: KRAS G12D mutation subtype was not significantly associated with poorer survival compared across the whole population of PDAC patients (p = 0.107; HR 1.293 95% CI (0.946-1.767)). However, KRAS G12D patients who were resectable had a shorter median survival time of 356 days compared to all other genotypes (median survival 810 days) (p = 0.019; HR 1.991 95% CI (1.121-3.537)). Conclusions: KRAS G12D patients who were resectable at diagnosis had shorter survival compared to all other PDAC patients. These data suggest that KRAS G12D may be a clinically useful prognostic biomarker of PDAC.

Circulating Tumor DNA Analysis Guiding Adjuvant Therapy in Stage II Colon Cancer.

BACKGROUND: The role of adjuvant chemotherapy in stage II colon cancer continues to be debated. The presence of circulating tumor DNA (ctDNA) after surgery predicts very poor recurrence-free survival, whereas its absence predicts a low risk of recurrence. The benefit of adjuvant chemotherapy for ctDNA-positive patients is not well understood. METHODS: We conducted a trial to assess whether a ctDNA-guided approach could reduce the use of adjuvant chemotherapy without compromising recurrence risk. Patients with stage II colon cancer were randomly assigned in a 2:1 ratio to have treatment decisions guided by either ctDNA results or standard clinicopathological features. For ctDNA-guided management, a ctDNA-positive result at 4 or 7 weeks after surgery prompted oxaliplatin-based or fluoropyrimidine chemotherapy. Patients who were ctDNA-negative were not treated. The primary efficacy end point was recurrence-free survival at 2 years. A key secondary end point was adjuvant chemotherapy use. RESULTS: Of the 455 patients who underwent randomization, 302 were assigned to ctDNA-guided management and 153 to standard management. The median follow-up was 37 months. A lower percentage of patients in the ctDNA-guided group than in the standard-management group received adjuvant chemotherapy (15% vs. 28%; relative risk, 1.82; 95% confidence interval [CI], 1.25 to 2.65). In the evaluation of 2-year recurrence-free survival, ctDNA-guided management was noninferior to standard management (93.5% and 92.4%, respectively; absolute difference, 1.1 percentage points; 95% CI, -4.1 to 6.2 [noninferiority margin, -8.5 percentage points]). Three-year recurrence-free survival was 86.4% among ctDNA-positive patients who received adjuvant chemotherapy and 92.5% among ctDNA-negative patients who did not. CONCLUSIONS: A ctDNA-guided approach to the treatment of stage II colon cancer reduced adjuvant chemotherapy use without compromising recurrence-free survival. (Supported by the Australian National Health and Medical Research Council and others; DYNAMIC Australian New Zealand Clinical Trials Registry number, ACTRN12615000381583.).

Lynch syndrome testing of colorectal cancer patients in a high-income country with universal healthcare: a retrospective study of current practice and gaps in seven australian hospitals.

BACKGROUND: To inform effective genomic medicine strategies, it is important to examine current approaches and gaps in well-established applications. Lynch syndrome (LS) causes 3-5% of colorectal cancers (CRCs). While guidelines commonly recommend LS tumour testing of all CRC patients, implementation in health systems is known to be highly variable. To provide insights on the heterogeneity in practice and current bottlenecks in a high-income country with universal healthcare, we characterise the approaches and gaps in LS testing and referral in seven Australian hospitals across three states. METHODS: We obtained surgery, pathology, and genetics services data for 1,624 patients who underwent CRC resections from 01/01/2017 to 31/12/2018 in the included hospitals. RESULTS: Tumour testing approaches differed between hospitals, with 0-19% of patients missing mismatch repair deficiency test results (total 211/1,624 patients). Tumour tests to exclude somatic MLH1 loss were incomplete at five hospitals (42/187 patients). Of 74 patients with tumour tests completed appropriately and indicating high risk of LS, 36 (49%) were missing a record of referral to genetics services for diagnostic testing, with higher missingness for older patients (0% of patients aged ≤ 40 years, 76% of patients aged > 70 years). Of 38 patients with high-risk tumour test results and genetics services referral, diagnostic testing was carried out for 25 (89%) and identified a LS pathogenic/likely pathogenic variant for 11 patients (44% of 25; 0.7% of 1,624 patients). CONCLUSIONS: Given the LS testing and referral gaps, further work is needed to identify strategies for successful integration of LS testing into clinical care, and provide a model for hereditary cancers and broader genomic medicine. Standardised reporting may help clinicians interpret tumour test results and initiate further actions.

EUS-FNA Biopsies to Guide Precision Medicine in Pancreatic Cancer: Results of a Pilot Study to Identify KRAS Wild-Type Tumours for Targeted Therapy.

BACKGROUND: Pancreatic ductal adenocarcinoma (PDAC) is a leading cause of cancer death and lacks effective treatment options. Diagnostic endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) biopsies represent an appealing source of material for molecular analysis to inform targeted therapy, as they are often the only available tissue for patients presenting with PDAC irrespective of disease stage. However, EUS-FNA biopsies are typically not used to screen for precision medicine studies due to concerns about low tissue yield and quality. Epidermal growth factor receptor (EGFR) inhibition has shown promise in clinical trials of unselected patients with advanced pancreatic cancer, but has not been prospectively tested in KRAS wild-type patients. Here, we examine the clinical utility of EUS-FNA biopsies for molecular screening of KRAS wild-type PDAC patients for targeted anti-EGFR therapy to assess the feasibility of this approach. PATIENTS AND METHODS: Fresh frozen EUS-FNA or surgical biopsies from PDAC patient tumours were used to screen for KRAS mutations. Eligible patients with recurrent, locally advanced, or metastatic KRAS wild-type status who had received at least one prior line of chemotherapy were enrolled in a pilot study (ACTRN12617000540314) and treated with panitumumab at 6mg/kg intravenously every 2 weeks until progression or unacceptable toxicity. The primary endpoint was 4-month progression-free survival (PFS). RESULTS: 275 patient biopsies were screened for KRAS mutations, which were detected in 88.3% of patient samples. 8 eligible KRAS wild-type patients were enrolled onto the interventional study between November 2017 and December 2020 and treated with panitumumab. 4-month PFS was 14.3% with no objective tumour responses observed. The only grade 3/4 treatment related toxicity observed was hypomagnesaemia. CONCLUSIONS: This study demonstrates proof-of-principle feasibility to molecularly screen patients with pancreatic cancer for targeted therapies, and confirms diagnostic EUS-FNA biopsies as a reliable source of tumour material for molecular analysis. Single agent panitumumab was safe and tolerable but led to no objective tumour responses in this population.

The EUS molecular evaluation of pancreatic cancer: A prospective multicenter cohort trial.

BACKGROUND AND OBJECTIVES: Patients with locally advanced or metastatic pancreatic ductal adenocarcinoma (A-PDAC) are not candidates for surgical resection and are often offered palliative chemotherapy. The ready availability of a safe and effective tumor sampling technique to provide material for both diagnosis and comprehensive genetic profiling is critical for informing precision medicine in A-PDAC, thus potentially increasing survival. The aim of this study is to examine the feasibility and benefits of routine comprehensive genomic profiling (CGP) of A-PDAC using EUS-FNA material. METHODS: This is a prospective cohort study to test the clinical utility of fresh frozen or archival EUS-FNA samples in providing genetic material for CGP. The results of the CGP will be reviewed at a molecular tumor board. The proportion of participants that have a change in their treatment recommendations based on their individual genomic profiling will be assessed. Correlations between CGP and stage, prognosis, response to treatment and overall survival will also be investigated. This study will open to recruitment in 2020, with a target accrual of 150 A-PDAC patients within 36 months, with a 2-year follow-up. It is expected that the majority of participants will be those who have already consented for their tissue to be biobanked in the Victorian Pancreatic Cancer Biobank at the time of diagnostic EUS-FNA. Patients without archival or biobanked material that is suitable for CGP may be offered a EUS-FNA procedure for the purposes of obtaining fresh frozen material. DISCUSSION: This trial is expected to provide crucial data regarding the feasibility of routine CGP of A-PDAC using EUS-FNA material. It will also provide important information about the impact of this methodology on patients' survival.

Enhanced toxicity with CDK 4/6 inhibitors and palliative radiotherapy: Non-consecutive case series and review of the literature.

Current first-line systemic treatment in most patients with metastatic hormone receptor-positive, HER-2 negative breast cancer is an aromatase inhibitor in combination with a cyclin dependant kinase (CDK) 4/6 inhibitor. Frequently, these patients require palliative radiotherapy (RT) for symptomatic disease management. There is a paucity of data on the safety of combining a CDK 4/6 inhibitor with palliative RT, with conflicting case reports in the literature. We report on 5 cases at our institution where enhanced radiotherapy toxicity was observed when palliative doses of RT was delivered during or prior to treatment with a CDK 4/6 inhibitor. After review of pre-clinical and mechanistic data, we hypothesise that the effects of CDK4/6 inhibition on normal tissue and the tumour microenvironment may impede tissue recovery and exacerbate acute radiation and radiation recall toxicities. Further studies are required to clarify the potential toxicities of this combination. Clinicians should consider the potential risks when combining CDK 4/6 inhibitors with palliative RT and individualise patient management accordingly.

The AGITG GAP Study: A Phase II Study of Perioperative Gemcitabine and Nab-Paclitaxel for Resectable Pancreas Cancer.

BACKGROUND: While combination therapy with nab-paclitaxel/gemcitabine (nab-gem) is effective in pancreatic ductal adenocarcinoma (PDAC), its efficacy as perioperative chemotherapy is unknown. The primary objective of this multicenter, prospective, single-arm, phase II study was to determine whether neoadjuvant therapy with nab-gem was associated with higher complete resection rates (R0) in resectable PDAC, while the secondary objectives were to determine the utility of radiological assessment of response to preoperative chemotherapy and the safety and efficacy of nab-gem as perioperative therapy. METHODS: Patients were recruited from eight Australian sites, and 42 patients with radiologically defined resectable PDAC and an Eastern Cooperative Oncology Group performance status of 0-2 were enrolled. Participants received two cycles of preoperative nab-paclitaxel 125 mg/m2 and gemcitabine 1000 mg/m2 on days 1, 8, and 15 (28-day cycle) presurgery, and four cycles postoperatively. Early response to chemotherapy was measured with fluorodeoxyglucose-positron emission tomography/computed tomography (FDG-PET/CT) scans on day 15. RESULTS: Preoperative nab-gem was completed by 93% of participants, but only 63% postoperatively. Thirty-six patients had surgery: 6 (17%) were unresectable, 15 (52%) had R0 (≥ 1 mm) resections, 14 (48%) had R1 (< 1 mm) resections, and 1 patient did not have PDAC. Median progression-free survival was 12.3 months and median overall survival (OS) was 23.5 months: R0 patients had an OS of 35 months versus 25.6 months for R1 patients after surgery. Seven patients had not progressed after 43 months. CONCLUSIONS: The GAP trial demonstrated that perioperative nab-gem was tolerable. Although the primary endpoint of an 85% R0 rate was not met, the R0 rate was similar to trials using a > 1 mm R0 resection definition, and survival rates were comparable with recent adjuvant studies.

Plants make galls to accommodate foreigners: some are friends, most are foes.

At the colonization site of a foreign entity, plant cells alter their trajectory of growth and development. The resulting structure - a plant gall - accommodates various needs of the foreigner, which are phylogenetically diverse: viruses, bacteria, protozoa, oomycetes, true fungi, parasitic plants, and many types of animals, including rotifers, nematodes, insects, and mites. The plant species that make galls also are diverse. We assume gall production costs the plant. All is well if the foreigner provides a gift that makes up for the cost. Nitrogen-fixing nodule-inducing bacteria provide nutritional services. Gall wasps pollinate fig trees. Unfortunately for plants, most galls are made for foes, some of which are deeply studied pathogens and pests: Agrobacterium tumefaciens, Rhodococcus fascians, Xanthomonas citri, Pseudomonas savastanoi, Pantoea agglomerans, 'Candidatus' phytoplasma, rust fungi, Ustilago smuts, root knot and cyst nematodes, and gall midges. Galls are an understudied phenomenon in plant developmental biology. We propose gall inception for discovering unifying features of the galls that plants make for friends and foes, talk about molecules that plants and gall-inducers use to get what they want from each other, raise the question of whether plants colonized by arbuscular mycorrhizal fungi respond in a gall-like manner, and present a research agenda.

Tumor inherent interferon regulators as biomarkers of long-term chemotherapeutic response in TNBC.

Patients diagnosed with triple negative breast cancer (TNBC) have an increased risk of rapid metastasis compared to other subtypes. Predicting long-term survival post-chemotherapy in patients with TNBC is difficult, yet enhanced infiltration of tumor infiltrating lymphocytes (TILs) has been associated with therapeutic response and reduced risk of metastatic relapse. Immune biomarkers that predict the immune state of a tumor and risk of metastatic relapse pre- or mid-neoadjuvant chemotherapy are urgently needed to allow earlier implementation of alternate therapies that may reduce TNBC patient mortality. Utilizing a neoadjuvant chemotherapy trial where TNBC patients had sequential biopsies taken, we demonstrate that measurement of T-cell subsets and effector function, specifically CD45RO expression, throughout chemotherapy predicts risk of metastatic relapse. Furthermore, we identified the tumor inherent interferon regulatory factor IRF9 as a marker of active intratumoral type I and II interferon (IFN) signaling and reduced risk of distant relapse. Functional implications of tumor intrinsic IFN signaling were demonstrated using an immunocompetent mouse model of TNBC, where enhanced type I IFN signaling increased anti-tumor immunity and metastasis-free survival post-chemotherapy. Using two independent adjuvant cohorts we were able to validate loss of IRF9 as a poor prognostic biomarker pre-chemotherapy. Thus, IRF9 expression may offer early insight into TNBC patient prognosis and tumor heat, allowing for identification of patients that are unlikely to respond to chemotherapy alone and could benefit from further immune-based therapeutic intervention.

nab-Paclitaxel plus gemcitabine in metastatic pancreatic adenocarcinoma: Australian subset analyses of the phase III MPACT trial.

AIM: The phase III MPACT trial (N = 861) demonstrated superior overall survival (OS) with first-line nab-paclitaxel plus gemcitabine versus gemcitabine alone (median, 8.7 months vs 6.6 months; hazard ratio [HR], 0.72; 95% confidence interval [CI], 0.62-0.83; P < 0.001) in patients with metastatic pancreatic cancer. The efficacy benefit of the combination over gemcitabine alone was observed across patient subgroups, including those based on region. This subset analysis was designed to examine the safety and efficacy of nab-paclitaxel plus gemcitabine in patients treated in Australia to understand whether differences in patient population or regional variations in patient care had any impact on clinical outcomes. METHODS: Patients with metastatic pancreatic cancer received first-line nab-paclitaxel plus gemcitabine or gemcitabine alone in the MPACT study; this analysis focused on those treated in Australia. RESULTS: In the Australian cohort, 120 patients were randomized to receive nab-paclitaxel plus gemcitabine (n = 61) or gemcitabine alone (n = 59). Median OS was 9.4 months with nab-paclitaxel plus gemcitabine versus 6.7 months with gemcitabine alone (HR, 0.64; 95% CI, 0.44-0.94; P = 0.022). Progression-free survival (median, 5.5 months vs 3.6 months; HR, 0.65; 95% CI, 0.42-1.00; P = 0.049) and the overall response rate (23% vs 2%; P < 0.001) were significantly improved with the combination. No new safety signals were observed. CONCLUSIONS: The results of this subset analysis confirm the efficacy and manageable safety profile of nab-paclitaxel plus gemcitabine in patients with metastatic pancreatic cancer treated in Australia.

Preliminary Evidence for Enhanced Thymine Absorption: A Putative New Phenotype Associated With Fluoropyrimidine Toxicity in Cancer Patients.

BACKGROUND: Chemotherapy for colorectal, head and neck, and breast cancer continues to rely heavily on 5-fluorouracil and its oral prodrug capecitabine. Associations of serious fluoropyrimidine adverse effects have focused on inherited deficiency of the catabolic enzyme, dihydropyrimidine dehydrogenase. However, abnormal dihydropyrimidine dehydrogenase activity accounts for only about one-third of observed toxicity cases. Thus, the cause of most fluorouracil toxicity cases remains unexplained. METHODS: For this small cohort study, thymine (THY) 250 mg was administered orally to 6 patients who had experienced severe toxicity during treatment with 5FU or capecitabine. Plasma and urine were analyzed for THY and its catabolites dihydrothymine (DHT) and ß-ureidoisobutyrate. RESULTS: Of the 6 patients, 2 had decreased THY elimination and raised urinary THY recovery consistent with inherited partial dihydropyrimidine dehydrogenase deficiency, confirmed by DPYD sequencing. Unexpectedly, 3 patients displayed grossly raised plasma THY concentrations but normal elimination profiles (compared with a normal range for healthy volunteers previously published by the authors). DPYD and DPYS sequencing of these 3 patients did not reveal any significant loss-of-activity allelic variants. The authors labeled the phenotype in these 3 patients as "enhanced thymine absorption". Only 1 of the 6 cases of toxicity had a normal postdose plasma profile for THY and its catabolites. Postdose urine collections from all 6 patients had THY/DHT urinary ratios above 4.0, clearly separated from the ratios in healthy subjects that were all below 3.0. CONCLUSIONS: This small cohort provided evidence for a hypothesis that fluorouracil toxicity cases may include a previously undescribed pyrimidine absorption variant, "enhanced thymine absorption," and elevated THY/DHT ratios in urine may predict fluorouracil toxicity. A prospective study is currently being conducted.

Psychological outcomes and surgical decisions after genetic testing in women newly diagnosed with breast cancer with and without a family history.

In patients with early breast cancer, personal and tumour characteristics other than family history are increasingly used to prompt genetic testing to guide women's cancer management (treatment-focused genetic testing, 'TFGT'). Women without a known strong family history of breast and/or ovarian may be more vulnerable to psychological sequelae arising from TFGT. We compared the impact of TFGT in women with (FH+) and without (FH-) a strong family history on psychological adjustment and surgical decisions. Women aged <50 years with high-risk features were offered TFGT before definitive breast cancer surgery and completed self-report questionnaires at four time points over 12 months. All 128 women opted for TFGT. TFGT identified 18 carriers of a disease-causing variant (50.0% FH+) and 110 non-carriers (59.1% FH+). There were no differences based on family history in bilateral mastectomy (BM) uptake, p = .190, or uptake of risk-reducing bilateral salpingo-oophorectomy (RRBSO), p = .093. FH- women had lower decreases in anxiety a year after diagnosis, p = .011, and regret regarding their decision whether to undergo BM, p = .022, or RRBSO, p = .016 than FH + women. FH- carriers reported significantly higher regret regarding their TFGT choice (p = .024) and test-related distress (p = .012) than FH + carriers, but this regret/distress could not be attributed to a concern regarding a possible worse prognosis. These findings indicate that FH- women may require additional counselling to facilitate informed decisions. Carriers without a family history may require additional follow-up counselling to facilitate psychological adjustment to their positive variant results, extra support in making surgical decisions, and counselling about how best to communicate results to family members.

Streamlined genetic education is effective in preparing women newly diagnosed with breast cancer for decision making about treatment-focused genetic testing: a randomized controlled noninferiority trial.

PURPOSE: Increasingly, women newly diagnosed with breast cancer are being offered treatment-focused genetic testing (TFGT). As the demand for TFGT increases, streamlined methods of genetic education are needed. METHODS: In this noninferiority trial, women aged <50 years with either a strong family history (FH+) or other features suggestive of a germ-line mutation (FH-) were randomized before definitive breast cancer surgery to receive TFGT education either as brief written materials (intervention group (IG)) or during a genetic counseling session at a familial cancer clinic (usual-care group (UCG)). Women completed self-report questionnaires at four time points over 12 months. RESULTS: A total of 135 women were included in the analysis, all of whom opted for TFGT. Decisional conflict about TFGT choice (primary outcome) was not inferior in the IG compared with the UCG (noninferiority margin of -10; mean difference = 2.45; 95% confidence interval -2.87-7.76; P = 0.36). Costs per woman counseled in the IG were significantly lower (AUD$89) compared with the UCG (AUD$173; t(115) = 6.02; P < 0.001). CONCLUSION: A streamlined model of educating women newly diagnosed with breast cancer about TFGT seems to be a cost-effective way of delivering education while ensuring that women feel informed and supported in their decision making, thus freeing resources for other women to access TFGT.Genet Med 19 4, 448-456.