Given a passage with a context and an answer, construct a question on the basis of the information present in the passage. Construct the question in such a way that (i) it is unambiguous, (ii) it is answerable from the passage, (iii) its answer is unique (iv) it answer uses text phrases from the passage. Avoid creating questions that (i) can't be answered correctly without actually understanding the passage and (ii) uses the same words or phrases given in the passage.

Example Input: Context: The role of Helicobacter pylori in gastro-oesophageal reflux disease (GERD) is controversial.', 'To compare the severity of GERD in infected vs. non-infected patients, as part of an ongoing randomized controlled trial that examines the impact of H. pylori eradication on GERD-related outcomes.', 'Consecutive GERD patients underwent urea breath testing and completed validated GERD symptom severity, and quality of life questionnaires as well as, 24-h pH-metry. These parameters, as well as demographics and endoscopic findings were assessed in double-blinded fashion and compared between H. pylori-infected and non-infected subjects.', "Helicobacter pylori-infected GERD patients (n=50) were significantly older and less educated than non-infected patients (n=51). They also used proton pump inhibitors less often but had no difference in symptoms (as measured with both the Spechler's Activity Index and the Gastrointestinal Symptom Rating Scale), quality of life, endoscopic findings or 24-h pH-metry findings.
Answer: This prospective, double-blind study demonstrates, using excellent GERD quantifying measures including validated symptom severity scores, endoscopy, and 24-h pH-metry, that there exist no clinically significant differences in clinical or laboratory-related GERD manifestations between H. pylori-infected and non-infected GERD patients.
Example Output: Is there no difference in the disease severity of gastro-oesophageal reflux disease between patients infected and not infected with Helicobacter pylori?

Example Input: Context: Is a perioperative metastatic screening programme indicated in patients presenting with primary operable breast cancer and no signs of distant metastases?', 'The impact of staging results (chest X-ray, bone scanning, liver ultrasound) for prognosis, treatment, quality of life and costs was retrospectively analysed in 1 076 patients with an operable breast cancer and no clinical signs of metastases.', 'Staging examinations revealed 30 (2.8 %) distant metastases, 130 (12.1 %) suspect findings and excluded metastases in 916 (85.1 %) patients. Further diagnostic procedures confirmed distant metastases in 7 (5.4 %) and excluded them in 123 (94.6 %) out of 130 patients with suspect findings. Distant metastases were detected more frequently with increasing tumor size (pT < or = 2.0 cm: 1.6 %, pT 2.1-5.0 cm: 3.0 %, respectively pT > 5.0 cm: 15.1 %; p < 0.001) and increasing number of involved axillary lymph nodes (pN0: 1.4 %, pN1-3 +: 1.8 %, pN4-9 +: 4.0 %, pN > 10 +: 12.5 %; p < 0.001). Due to false positive findings 123 (11.4 %) patients had to live for a significant period of time with the psychological distress of suspected metastatic disease. The abandonment of a perioperative screening in 1 076 patients saves costs of at least euro 259,366.68.
Answer: In breast cancer patients without clinical signs of tumor spread perioperative screening for metastases is not warranted because of low frequency of metastases, false positive findings, missing therapeutic consequences and high costs.
Example Output: Is [ A perioperative screening for metastatic disease indicated in patients with primary breast cancer and no clinical signs of tumor spread ]?

Example Input: Context: The aim of this study was to determine the clinical significance and prognostic impact of extranodal metastasis (EM) in gastric carcinoma.', 'The study included 1023 patients who underwent gastrectomy with lymphadenectomy for primary gastric carcinoma between January 1993 and December 1996. EM was defined as the presence of tumour cells in extramural soft tissue that was discontinuous with either the primary lesion or locoregional lymph nodes.', "EM was detected in 146 (14.3 per cent) of the 1023 patients and in 1060 (3.0 per cent) of the 35 811 nodules that were retrieved as 'lymph nodes' from adipose connective tissues. The incidence of EM was significantly higher in patients with tumours that were large (diameter 10 cm or more), infiltrative, deeply invading or undifferentiated and in those with lymph node, peritoneal or liver metastases, or lymphatic or vascular involvement. After curative operation overall survival was significantly worse for patients with EM than those without (P < 0.001). Multivariate analysis identified EM as an independent prognostic factor (hazard ratio 1.82 (95 per cent confidence interval 1.23 to 2.71); P = 0.003).
Answer: EM is an independent prognostic factor and should therefore be included in the tumour node metastasis (TNM) staging system.
Example Output:
Is extranodal metastasis an indicator of poor prognosis in patients with gastric carcinoma?