Circulating tumor-derived DNA (ctDNA) can be used to monitor cancer dynamics noninvasively. Detection of ctDNA can be challenging in patients with low-volume or residual disease, where plasma contains very few tumor-derived DNA fragments. We show that sensitivity for ctDNA detection in plasma can be improved by analyzing hundreds to thousands of mutations that are first identified by tumor genotyping. We describe the INtegration of VAriant Reads (INVAR) pipeline, which combines custom error-suppression methods and signal-enrichment approaches based on biological features of ctDNA. With this approach, the detection limit in each sample can be estimated independently based on the number of informative reads sequenced across multiple patient-specific loci. We applied INVAR to custom hybrid-capture sequencing data from 176 plasma samples from 105 patients with melanoma, lung, renal, glioma, and breast cancer across both early and advanced disease. By integrating signal across a median of >105 informative reads, ctDNA was routinely quantified to 1 mutant molecule per 100,000, and in some cases with high tumor mutation burden and/or plasma input material, to parts per million. This resulted in median area under the curve (AUC) values of 0.98 in advanced cancers and 0.80 in early-stage and challenging settings for ctDNA detection. We generalized this method to whole-exome and whole-genome sequencing, showing that INVAR may be applied without requiring personalized sequencing panels so long as a tumor mutation list is available. As tumor sequencing becomes increasingly performed, such methods for personalized cancer monitoring may enhance the sensitivity of cancer liquid biopsies.
BackgroundBevacizumab is a recombinant humanised monoclonal antibody to vascular endothelial growth factor shown to improve survival in advanced solid cancers. We evaluated the role of adjuvant bevacizumab in melanoma patients at high risk of recurrence.Patients and methodsPatients with resected AJCC stage IIB, IIC and III cutaneous melanoma were randomised to receive either adjuvant bevacizumab (7.5 mg/kg i.v. 3 weekly for 1 year) or standard observation. The primary end point was detection of an 8% difference in 5-year overall survival (OS) rate; secondary end points included disease-free interval (DFI) and distant metastasis-free interval (DMFI). Tumour and blood were analysed for prognostic and predictive markers.ResultsPatients (n=1343) recruited between 2007 and 2012 were predominantly stage III (73%), with median age 56 years (range 18–88 years). With 6.4-year median follow-up, 515 (38%) patients had died [254 (38%) bevacizumab; 261 (39%) observation]; 707 (53%) patients had disease recurrence [336 (50%) bevacizumab, 371 (55%) observation]. OS at 5 years was 64% for both groups [hazard ratio (HR) 0.98; 95% confidence interval (CI) 0.82–1.16, P = 0.78). At 5 years, 51% were disease free on bevacizumab versus 45% on observation (HR 0.85; 95% CI 0.74–0.99, P = 0.03), 58% were distant metastasis free on bevacizumab versus 54% on observation (HR 0.91; 95% CI 0.78–1.07, P = 0.25). Forty four percent of 682 melanomas assessed had a BRAFV600 mutation. In the observation arm, BRAF mutant patients had a trend towards poorer OS compared with BRAF wild-type patients (P = 0.06). BRAF mutation positivity trended towards better OS with bevacizumab (P = 0.21).ConclusionsAdjuvant bevacizumab after resection of high-risk melanoma improves DFI, but not OS. BRAF mutation status may predict for poorer OS untreated and potential benefit from bevacizumab.Clinical Trial InformationISRCTN 81261306; EudraCT Number: 2006-005505-64
PURPOSE Adjunct cervical cancer screening methods are under evaluation to improve the diagnostic accuracy of human papillomavirus (HPV)-based screening in low- and middle-income countries. We evaluated the feasibility and acceptability of smartphone-based cervicography among HPV-positive women living with HIV (WLWH) in Western Kenya. METHODS HPV-positive WLWH of 25-49 years of age enrolled in a clinical trial (ClinicalTrials.gov identifier: NCT04191967 ) had digital images of the cervix taken using a smartphone by a nonphysician provider following visual inspection with acetic acid. All participants had colposcopy-directed biopsy before treatment. Cervical images were evaluated by three off-site colposcopists for quality, diagnostic utility, and assigned a presumed diagnosis. We determined the proportion of images rates as low, medium, or high quality, interobserver agreement using Cohen’s Kappa statistic, and the off-site colposcopist’s sensitivity and specificity for diagnosis of cervical intraepithelial neoplasia grade 2 or worse (CIN2+) compared with histopathology. Acceptability was evaluated using a questionnaire. RESULTS One hundred sixty-four HPV-positive WLWH underwent cervicography during the study period. Mean age was 37.3 years. Images from the first 94 participants were evaluated by off-site colposcopists, with a majority (70.9%) rated as high quality. Off-site colposcopists had a sensitivity ranging from 21.4% (95% CI, 0.06 to 0.43) to 35.7% (95% CI, 0.26 to 0.46) and a specificity between 85.5% (95% CI, 0.81 to 0.90) to 94.9% (95% CI, 0.92 to 0.98) for diagnosis of CIN2+ based compared with histopathology. The majority of women, 99.4%, were comfortable having an image of their cervix taken as part of screening. CONCLUSION Cervicography by a nonphysician provider as an adjunct to HPV-based screening among WLWH in a low- and middle-income country setting is feasible and acceptable. However, low sensitivity for diagnosis of CIN2+ by off-site expert colposcopists highlights the limitations of cervicography.
Although cervical cancer is preventable, in 2018, approximately 570,000 new cases occurred globally. Cervical cancer disproportionately affects low-and middle-income countries (LMICs), which accounted for 90% of deaths in 2018. Women living with the Human Immunodeficiency Virus (WLWH) are at increased risk of cervical cancer and are in urgent need of prevention. Despite evidence-based guidelines for screening and prevention of cervical cancer, the majority of WLWH in LMICs lack access to cervical cancer screening. Despite tremendous gains made in access to life prolonging antiretroviral therapy for WLWH, most are served by vertical human immunodeficiency virus (HIV) programmes which do not integrate these two crucial services. We present a case of a WLWH, in HIV care for a decade, who was recently diagnosed with preventable, advanced stage cervical cancer.
In this stage II/III melanoma cohort, vitamin D did not correlate with known prognostic markers, nor predict for DFI or OS, but there was some evidence of benefit for patients with stage II disease treated with bevacizumab.
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