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.
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Question: 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.

Answer: Is [ A perioperative screening for metastatic disease indicated in patients with primary breast cancer and no clinical signs of tumor spread ]?


Question: Context: Macroprolactinemia is a frequent finding in hyperprolactinemic individuals, usually without clinical impact. Data on biological activity of macroprolactin (bbPRL) are controversial and mostly based on a heterologous rat Nb2 cell bioassay. Biological activity of bbPRL observed in vitro but not in vivo may be due to its high molecular weight, preventing its passage through capillary barrier. Alternatively, bbPRL bioactivity may differ depending on the prolactin (PRL) receptor (PRLR) species specificity.', 'The objective of the study was to characterize the bioactivity of bbPRL in a homologous bioassay: Ba/F-3 cells stably expressing the human PRLR.', "Chromatography-purified bbPRL from macroprolactinemic individuals (group I, n = 18) and monomeric PRL from hyperprolactinemic patients without macroprolactinemia (group II, n = 5) were tested in Nb2 and Ba/F-LLP bioassays. Both groups were followed up at the neuroendocrinology outpatients' clinic.", 'Biological activity of bbPRL presented in the two bioassays was measured.', 'In group I, no patient had hypogonadism. Mean ratio bioactivity to immunoactivity of bbPRL in the Nb2 assay was 0.69. There was no dose-response in 15 of the 18 samples tested in Ba/F-LLP assay. In group II, three patients had galactorrhea and all five had hypogonadism. Mean ratio bioactivity to immunoactivity of monomeric PRL samples was 1.35 in Nb2 and 0.91 in Ba/F-LLP assay.
Answer: Whereas both bioassays achieve similar results with respect to monomeric PRL activity, our results indicate that the activity displayed by bbPRL toward the rat receptor may be inappropriate because it is not observed in the human PRLR-mediated assay, consistent with the apparent absence of bioactivity in vivo.

Answer: Does human macroprolactin display low biological activity via its homologous receptor in a new sensitive bioassay?


Question: Context: The clinical significance of the hepatitis B virus core-related antigen (HBcrAg) assay in monitoring the antiviral effects of lamivudine is reviewed.', 'The HBcrAg assay simultaneously measured serum levels of hepatitis B core (HBc) and e (HBe) antigens using monoclonal antibodies which recognize common epitopes of these two denatured antigens.', 'Although serum HBcrAg levels correlated linearly with those of hepatitis B virus (HBV) DNA in natural course, the decrease in HBcrAg was significantly slower than in HBV DNA after initiation of lamivudine administration. We analyzed the clinical significance of HBV DNA and HBcrAg levels to predict the occurrence of lamivudine resistance. HBV DNA measurement may be useful to identify patients who are at high risk of developing lamivudine resistance, and HBcrAg measurement may help to detect patients who are at low risk of drug resistance. The measurement of HBcrAg was also found to be a useful prognosticator for reactivation of hepatitis after cessation of lamivudine administration.
Answer: The HBcrAg assay is indeed useful for monitoring the antiviral effects of lamivudine, and we propose that it be adopted as a serum marker which reflects the amount of HBV covalently closed circular DNA in hepatocytes.

Answer:
Is hepatitis B core-related antigen assay useful for monitoring the antiviral effects of nucleoside analogue therapy?