In this task, you are given a passage which has a question and the context. You have to generate an answer to the question based on the information present in the context.

[EX Q]: Context: Urinary dysfunction (UD) is common after rectal cancer treatment, but the contribution of each treatment component (surgery and radiotherapy) to its development remains unclear. This study aimed to evaluate UD during 5 years after total mesorectal excision (TME) and to investigate the influence of preoperative radiotherapy (PRT) and surgical factors.', 'Patients with operable rectal cancer were randomized to TME with or without PRT. Questionnaires concerning UD were completed by 785 patients before and at several time points after surgery. Possible risk factors, including PRT, demographics, tumour location, and type and extent of resection, were investigated by multivariable regression analysis.', 'Long-term incontinence was reported by 38.1 per cent of patients, of whom 72.0 per cent had normal preoperative function. Preoperative incontinence (relative risk (RR) 2.75, P = 0.001) and female sex (RR 2.77, P < 0.001) were independent risk factors. Long-term difficulty in bladder emptying was reported by 30.6 per cent of patients, of whom 65.0 per cent had normal preoperative function. Preoperative difficulty in bladder emptying (RR 2.94, P < 0.001), peroperative blood loss (RR 1.73, P = 0.028) and autonomic nerve damage (RR 2.82, P = 0.024) were independent risk factors. PRT was not associated with UD.\Question: Is urinary dysfunction after rectal cancer treatment mainly caused by surgery?
[EX A]: UD is a significant clinical problem after rectal cancer treatment and is not related to PRT, but rather to surgical nerve damage.

[EX Q]: Context: To determine whether cancer antigen-125 (CA-125) levels are increased in women with endometriosis, especially in those with endometriomas (OMAs), deep infiltrating lesions (DIE), and superficial endometriosis (SUP) compared with controls without endometriosis in a large cohort of operated women.', 'Cross-sectional study (Canadian Task Force classification II-2).', 'Tertiary-care university hospital.', 'Four hundred six women with histologically proven endometriosis and 279 women without endometriosis.', 'Surgical examination of the abdomino-pelvic cavity.', 'Preoperative serum CA-125 antigen levels were evaluated by electrochemoluminescence immunoassay in women with endometriosis and controls. Correlations between serum CA-125 levels and clinical and anatomical characteristics of disease severity were examined. Women with endometriosis displayed higher mean serum CA-125 levels compared with disease-free controls (50.1\xa0±\xa062.4 U/mL vs 22.5\xa0±\xa025.2 U/mL; p\xa0≤\xa0.001). CA-125 levels were significantly increased in women with OMA (60.8\xa0±\xa063.5 U/mL) and DIE (55.2\xa0±\xa068.7 U/mL) compared with women with SUP (23.2\xa0±\xa024.5 U/mL) and controls (22.5\xa0±\xa025.2 U/mL). There was no difference in CA-125 levels between patients with SUP and controls and between patients with OMA and DIE. CA-125 serum levels were correlated with DIE severity: the mean number of DIE lesions and worst DIE lesion.\Question: Is increased serum cancer antigen-125 a marker for severity of deep endometriosis?
[EX A]: Serum CA-125 levels were significantly increased in women with severe forms of endometriosis, OMA, and DIE lesions. In addition, elevated serum Ca-125 levels were associated with more severe and extended DIE lesions. In women with superficial peritoneal lesions, CA-125 levels were not different from women without endometriosis.

[EX Q]: Context: To determine the frequency of hyperintense cortical signal (HCS) on T1-weighted precontrast magnetic resonance (MR) images in progressive multifocal leukoencephalopathy (PML) patients, its association with seizure risk and immune reconstitution inflammatory syndrome (IRIS), and its pathologic correlate.', 'We reviewed clinical data including seizure history, presence of IRIS, and MR imaging scans from PML patients evaluated at our institution between 2003 and 2012. Cases that were diagnosed either using cerebrospinal fluid JC virus (JCV) polymerase chain reaction, brain biopsy, or autopsy, and who had MR images available were included in the analysis (n=49). We characterized pathologic findings in areas of the brain that displayed HCS in 2 patients and compared them with isointense cortex in the same individuals.', 'Of 49 patients, 17 (34.7%) had seizures and 30 (61.2%) had HCS adjacent to subcortical PML lesions on MR images. Of the 17 PML patients with seizures, 15 (88.2%) had HCS compared with 15 of 32 (46.9%) patients without seizures (p=0.006). HCS was associated with seizure development with a relative risk of 4.75 (95% confidence interval=1.2-18.5, p=0.006). Of the 20 patients with IRIS, 16 (80.0%) had HCS compared with 14 of 29 (49.3%) patients without IRIS (p=0.04). On histological examination, HCS areas were associated with striking JCV-associated demyelination of cortical and subcortical U fibers, significant macrophage infiltration, and a pronounced reactive gliosis in the deep cortical layers.\Question: Does hyperintense cortical signal on magnetic resonance imaging reflect focal leukocortical encephalitis and seizure risk in progressive multifocal leukoencephalopathy?
[EX A]:
Seizures are a frequent complication in PML. HCS is associated with seizures and IRIS, and correlates histologically with JCV focal leukocortical encephalitis.