Medical Biology - Research Publications

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    Impact of the evolution in RAS mutation analysis in Australian patients with metastatic colorectal cancer
    Chong, CY ; Jalali, A ; Wong, HL ; Loft, M ; Wong, R ; Lee, M ; Gately, L ; Hong, W ; Shapiro, J ; Kosmider, S ; Tie, J ; Ananda, S ; Yeung, JM ; Ma, B ; Burge, M ; Jennens, R ; Tran, B ; Lee, B ; Lim, L ; Dean, A ; Nott, L ; Gibbs, P (WILEY, 2022-10)
    BACKGROUND: RAS mutation testing now routinely informs the optimal management of metastatic colorectal cancer (mCRC), specifically the finding of a RAS mutation defines patients who will not benefit from treatment with an epidermal growth factor receptor inhibitor. Over time more RAS genes have been tested and more sensitive techniques used. AIMS: To review routine care RAS testing and results over time. METHODS: A retrospective analysis of the molecular data collected prospectively in the multi-site Treatment of Recurrent and Advanced Colorectal Cancer (TRACC) registry from 2009 to 2018 was undertaken. Patients with RAS data were further analyzed. In parallel, the RAS mutation status of patients enrolled in the Test Tailor Treat (TTT) program was examined for 2011-2018. RESULTS: Of 2908 patients in the TRACC registry, 1892 (65%) were tested, with 898 (47%) of tested patients found to be RAS mutant (RASmt). RAS data were available for 5935 TTT patients. Of the tested TRACC patients diagnosed in 2009 and 2010, 38% were RASmt. For each 2-year period from 2011/2012 through to 2017/2018, the prevalence of RASmt in TRACC and TTT was 42% and 40% (2011/2012), 52% and 40% (2013/2014), 47% and 49% (2015/2016), and 47% and 49% (2017/2018). CONCLUSIONS: Based on both TRACC and TTT data, the proportion of patients reported to have a RAS mutation increased from 2009 to 2015 but has remained relatively stable in recent years. The increased proportion of RASmt patients observed over time is likely largely driven by the uptake of extended RAS testing.
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    Use and outcomes of chemotherapy for metastatic pancreatic cancer in Australia
    Body, A ; Wong, R ; Shapiro, J ; Jalali, A ; McLachlan, S-A ; Ananda, S ; Lipton, L ; Cooray, P ; Gibbs, P ; Lee, B ; Lee, M (WILEY, 2022-01)
    BACKGROUND: Metastatic pancreatic ductal adenocarcinoma (mPDAC) is highly lethal. Combination chemotherapy regimens improve overall survival (OS). Historically, only one-third of mPDAC patients in Victoria received chemotherapy. AIM: To describe current Australian chemotherapy utilisation and outcomes in patients with mPDAC using the multi-site PURPLE (Pancreatic cancer: Understanding Routine Practice and Lifting End Results) registry. METHODS: PURPLE collects longitudinal data on consecutive patients with pancreatic cancer seen since January 2016. Data were collated for patients with mPDAC from six Victorian sites, and analysed descriptively. RESULTS: Three hundred and sixty-three patients with mPDAC were identified. Median age was 70 years (range 20-94 years). First-line chemotherapy was administered in 195 (54%) patients. Prevalent regimens included gemcitabine-nab-paclitaxel (71%), gemcitabine alone (10%) and FOLFIRINOX (6%). Sixty-two of 195 (32%) patients who received first line treatment have proceeded to second-line chemotherapy. Chemotherapy-treated patients were younger (69 versus 73 years; P < 0.01), with better Eastern Cooperative Oncology Group (ECOG) performance status (ECOG 0-1 89 vs 66%; P < 0.01) and lower median Charlson comorbidity index (3 vs 4; P < 0.01) compared with untreated patients. Median OS of the entire cohort from diagnosis of metastases was 5.1 months. Median OS was 9.3 months in the chemotherapy treated patients, and 2.5 months in chemotherapy-untreated patients (P < 0.01). CONCLUSIONS: A substantial proportion of patients with mPDAC still do not receive active treatment, which may in part by explained by age, poor performance status and comorbidity. Gemcitabine-nab-paclitaxel was the preferred first-line chemotherapy regimen. Median OS for treated patients in this cohort was comparable to that of recent published clinical trials.
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    Biology and Clinical Implications of Fecal Occult Blood Test Screen-Detected Colorectal Cancer
    Mendis, S ; Hong, W ; Ananda, S ; Faragher, I ; Jones, I ; Croxford, M ; Steel, M ; Jalali, A ; Gard, G ; To, YH ; Lee, M ; Kosmider, S ; Wong, R ; Tie, J ; Gibbs, P (OXFORD UNIV PRESS, 2022-01-05)
    BACKGROUND: Fecal occult blood test (FOBT)-based screening for colorectal cancer (CRC) reduces mortality, with earlier stage at diagnosis a prominent feature. Other characteristics of FOBT screen-detected cancers and any implications for clinical management have not been well explored. METHODS: We examined a multisite clinical registry to compare the characteristics and outcomes of FOBT screen-detected CRC via the Australian National Bowel Cancer Screening Program (NBCSP), which is offered biennially to individuals aged 50-74 years, and age-matched non-screen-detected CRC in the same registry. All statistical tests were 2-sided. Odds ratios (ORs) were calculated using the Baptista-Pike method, and hazard ratios via the log-rank method. RESULTS: Of 7153 registry patients diagnosed June 1, 2006, to June 30, 2020, 4142 (57.9%) were aged between 50 and 74 years. Excluding 406 patients with non-NBCSP screen-detected cancers and 35 patients with unknown method of detection, 473 (12.8%) were screen detected via the NBCSP, and 3228 (87.2%) were non-screen detected. Screen-detected patients were younger (mean age = 62.4 vs 64.2 years; P < .001) and more medically fit (OR for ASA score 1-2 = 1.91, 95% confidence interval [CI] = 1.51 to 2.41; P < .001). Pathologic characteristics within each stage favored the screen-detected patients. Stage III screen-detected colon cancers were more likely to receive adjuvant therapy (OR = 3.58, 95% CI = 1.52 to 8.36; P = .002). Screen-detected patients had superior relapse-free (hazard ratio = 0.41, 95% CI = 0.29 to 0.60; P < .001) and overall survival (hazard ratio = 0.22, 95% CI = 0.15 to 0.35; P < .001), which was maintained in matched stage comparisons and multivariable analysis. CONCLUSIONS: Beyond stage at diagnosis, multiple other factors associated with a favorable outcome are observed in FOBT screen-detected CRC. Given the substantial stage-by-stage differences in survival outcomes, if independently confirmed, individualized adjuvant therapy and surveillance strategies could be warranted for FOBT screen-detected cancers.
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    The impact of bevacizumab in metastatic colorectal cancer with an intact primary tumor: Results from a large prospective cohort study
    Lee, B ; Wong, H-L ; Tacey, M ; Tie, J ; Wong, R ; Lee, M ; Nott, L ; Shapiro, J ; Jennens, R ; Turner, N ; Tran, B ; Ananda, S ; Yip, D ; Richardson, G ; Parente, P ; Lim, L ; Stefanou, G ; Burge, M ; Iddawela, M ; Power, J ; Gibbs, P (WILEY, 2017-08)
    BACKGROUND: Debate continues regarding the benefits versus risks of initial resection of the primary tumor in metastatic colorectal cancer (mCRC) patients with an asymptomatic primary tumor. Although the benefit of the anti-vascular endothelial growth factor agent bevacizumab alongside first-line chemotherapy in mCRC is established, the impact of bevacizumab on the intact primary tumor (IPT) is less well understood. METHODS: Data from an Australian mCRC registry were used to assess the impact of bevacizumab-based regimens in the presence of an IPT, to see if this differs from effects in resected primary tumor (RPT) patients and to understand the safety profile of bevacizumab in patients with IPT. Progression-free survival (PFS), overall survival (OS) and safety endpoints were analyzed. RESULTS: Of 1204 mCRC patients, 826 (69%) were eligible for inclusion. Bevacizumab use was similar in both arms (IPT (64%) versus RPT (70%)); compared with chemotherapy alone, bevacizumab use was associated with significantly longer PFS (IPT: 8.5 months vs 4.7 months, P = 0.017; RPT: 10.8 months vs 5.8 months, P < 0.001) and OS (IPT: 20 months vs 14.8 months, P = 0.005; RPT: 24.4 months vs 17.3 months, P = 0.004)).1 Bevacizumab use in an IPT was associated with more GI perforations (4.5% vs 1.8%, P = 0.210) but less frequent bleeding (1.5% vs 5.3%, P = 0.050) and thrombosis (1.5% vs 2.7%, P = 0.470), versus chemotherapy alone. Median survival was equivalent between patients that did or did not experience bevacizumab-related adverse events - 20.0 months versus 19.9 months, hazard ratio = 0.98, P = 0.623.1 CONCLUSIONS: The addition of bevacizumab significantly improved survival outcomes in mCRC with an IPT. The occurrence of bevacizumab-related adverse events did not significantly impact survival outcomes.
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    Right versus left sided metastatic colorectal cancer: Teasing out clinicopathologic drivers of disparity in survival
    Mendis, S ; Beck, S ; Lee, B ; Lee, M ; Wong, R ; Kosmider, S ; Shapiro, J ; Yip, D ; Steel, S ; Nott, L ; Jennens, R ; Lipton, L ; Burge, M ; Field, K ; Ananda, S ; Wong, H-L ; Gibbs, P (WILEY, 2019-06)
    BACKGROUND: Metastatic colorectal cancer (mCRC) patients with a right-sided primary (RC) have an inferior survival to mCRC arising from a left-sided primary (LC). Previous analyses have suggested multiple factors contribute. METHODS: The Treatment of Recurrent and Advanced Colorectal Cancer (TRACC) Registry prospectively captured data on consecutive mCRC patients. RC were defined as tumors proximal to the splenic flexure; LC were those at and distal to the splenic flexure and included rectal cancers. Patient, tumor, treatment, and survival data were analyzed stratified by side. RESULTS: Of 2306 patients enrolled from July 2009-March 2018, 747 (32%) had an RC. Patients with RC were older, more likely to be female and have a Charlson score ≥3. RC were more frequently BRAF mutated, deficient in mismatch repair, associated with peritoneal metastases, and less likely to receive chemotherapy. Progression-free survival on first-line systemic therapy was inferior for RC patients (8.1 vs. 10.8 months, hazard ratio [HR] for progression in RC 1.38, P < 0.001). Median overall survival for all RC patients was inferior (19.6 vs. 27.5 months, HR for death in RC 1.44, P < 0.001), and inferior within the treated (21 vs. 29.5 months, HR 1.52, P < 0.001) and untreated subgroups (5.9 vs. 10.3 months, HR 1.38, P = 0.009). Primary side remained a significant factor for overall survival in multivariate analysis. CONCLUSION: Our data from a real-world population confirms the poorer prognosis associated with RC. Primary tumor location remains significantly associated with overall survival even when adjusting for multiple factors, indicating the existence of further side-based differences that are as yet undefined.