Biography:

In the past K. Nadine Phoa has collaborated on articles with Frederike G.I. van Vilsteren. One of their most recent publications is Original ResearchFull Report: Clinical—Alimentary TractRemission of Barrett's Esophagus With Early Neoplasia 5 Years After Radiofrequency Ablation With Endoscopic Resection: A Netherlands Cohort Study. Which was published in journal Gastroenterology.

More information about K. Nadine Phoa research including statistics on their citations can be found on their Copernicus Academic profile page.

K. Nadine Phoa's Articles: (3)

Original ResearchFull Report: Clinical—Alimentary TractRemission of Barrett's Esophagus With Early Neoplasia 5 Years After Radiofrequency Ablation With Endoscopic Resection: A Netherlands Cohort Study

Background & AimsRadiofrequency ablation (RFA), with or without endoscopic resection effectively eradicates Barrett’s esophagus (BE) containing high-grade intraepithelial neoplasia and/or early-stage cancer. We followed patients who received RFA for BE containing high-grade intraepithelial neoplasia and/or early-stage cancer for 5 years to determine the durability of treatment response.MethodsWe followed 54 patients with BE (2−12 cm), previously enrolled in 4 consecutive cohort studies in which they underwent focal endoscopic resection in case of visible lesions (n = 40 [72%]), followed by serial RFA every 3 months. Patients underwent high-resolution endoscopy with narrow-band imaging at 6 and 12 months after treatment and then annually for 5 years (median, 61 months; interquartile range, 53−65 months); random biopsy samples were collected from neosquamous epithelium and gastric cardia. After 5 years, endoscopic ultrasound and endoscopic resection of neosquamous epithelium were performed. Outcomes included sustained complete remission of neoplasia or intestinal metaplasia (IM), IM in gastric cardia, or buried glands in neosquamous epithelium.ResultsAfter 5 years, Kaplan-Meier analysis showed sustained complete remission of neoplasia and intestinal metaplasia in 90% of patients; neoplasia recurred in 3 patients and was managed endoscopically. Focal IM in the cardia was found in 19 of 54 patients (35%), in 53 of 1143 gastric cardia biopsies (4.6%). The incidence of IM of the cardia did not increase over time; and IM was diagnosed based on only a single biopsy in 89% of patients. Buried glands were detected in 3 of 3543 neosquamous epithelium biopsies (0.08%, from 3 patients). No endoscopic resection samples had buried glands.ConclusionsAmong patients who have undergone RFA with or without endoscopic resection for neoplastic BE, 90% remain in remission at 5-year follow-up, with all recurrences managed endoscopically. This treatment approach is therefore an effective and durable alternative to esophagectomy; www.trialregister.nl number, NTR2938.

Original articleClinical endoscopyA simplified regimen for focal radiofrequency ablation of Barrett's mucosa: a randomized multicenter trial comparing two ablation regimens

BackgroundThe currently recommended regimen for focal radiofrequency ablation (RFA) of Barrett's esophagus (BE) comprises 2 applications of energy, cleaning of the device and ablation zone, and 2 additional applications of energy. A simplified regimen may be of clinical utility if it is faster, easier, and equally safe and effective.ObjectiveTo compare the efficacy of 2 focal RFA regimens.SettingThree tertiary referral centers.PatientsConsecutive patients scheduled for focal RFA of BE with flat type BE with at least 2 BE islands or mosaic groups of islands were enrolled.InterventionsBE areas were paired: 1 area was randomized to the “standard” regimen (2 × 15 J/cm2–clean–2 × 15 J/cm2) or to the “simplified” regimen (3 × 15 J/cm2–no clean), allocating the second area automatically to the other regimen. The percentage of surface area regression of each area was scored at 2 months by the endoscopist (blinded).Outcome MeasureProportion of completely removed BE areas at 2 months. Calculated sample size was 46 pairs of BE areas using a noninferiority design. Noninferiority was defined as <20% difference in the paired proportions.ResultsForty-five equivalent pairs of BE areas were included in 41 patients. The proportion of completely removed BE areas at 2 months after focal RFA was 30 (67%) for standard and 33 (73%) for simplified. Noninferiority was demonstrated by a 7% difference (95% CI, −10.6 to +20.9).LimitationsTertiary referral centers.ConclusionsThe results of this multicenter randomized trial suggest that a simplified 3 × 15 J/cm2 focal ablation regimen is not inferior to the standard regimen, regarding the endoscopic removal of residual Barrett islands.

Original articleAlimentary tractCircumferential Balloon-based Radiofrequency Ablation of Barrett's Esophagus With Dysplasia Can Be Simplified, yet Efficacy Maintained, by Omitting the Cleaning Phase

Background & AimsThe current procedure for circumferential balloon-based radiofrequency ablation (c-RFA) for the removal of dysplastic Barrett's esophagus (BE) is labor intensive, comprising 2 ablation passes with a cleaning step to remove debris from the ablation zone and electrode. We compared the safety and efficacy of 3 different c-RFA ablation regimens.MethodsWe performed a prospective trial of consecutive patients with flat-type BE with high-grade dysplasia. Fifty-seven patients (45 men; age, 64 ± 15 y; 28 with prior endoscopic resection) were assigned randomly to groups that underwent c-RFA with a double application of RFA (12 J/cm2). The standard group received c-RFA, with device removal and cleaning, followed by c-RFA; the simple-with-cleaning group underwent c-RFA, with device cleaning without removal, followed by c-RFA; and the simple-no-cleaning group received 2 applications of c-RFA, and the device was not removed or cleaned. The primary outcome was surface regression of BE 3 months later, graded by 2 blinded expert endoscopists. Calculated sample size was 57 patients, based on a noninferiority design.ResultsMedian BE surface regression at 3 months was 83% in the standard group, 78% in the simple-with-cleaning group, and 88% in the simple-no-cleaning group (P = .14). RF ablation time was 20 minutes (interquartile range [IQR], 18–25 min) for the standard group, 13 minutes (IQR, 11–15 min) for the simple-with-cleaning group, and 5 minutes (IQR, 5–9 min) for the simple-no-cleaning group (P < .01). The median number of introductions (RFA devices/endoscope) for the standard group was 7, vs 4 for the simple groups (P < .01).ConclusionsThis randomized, prospective study suggests that c-RFA is easier and faster, but equally safe and effective, when the cleaning phase between ablations is omitted or simplified. Trialregister.nl, NTR 2495.

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