Significant drop in serum C-reactive protein in patients with solid neoplasia and bacterial infection is associated with a better prognosis and identifies candidates for short-course antibiotic therapy.

INTRODUCTION: The greater predisposition to infections, as well as the possibility of a worse response to treatment, can lead to the excessive use of antimicrobials among cancer patients. C-reactive protein (CRP) has gained prominence as a tool for monitoring therapeutic responses and reducing the duration of antibiotic therapy; however, few studies have analyzed this protein in cancer patient populations. We hypothesize that cancer patients with a good response to antibiotic therapy show a faster decline in serum CRP levels, which would allow us to identify candidates for short-course treatments. OBJECTIVE: To evaluate the behavior of serum CRP levels among adult cancer patients using antibiotic therapy, and its association with the duration of this treatment, therapeutic response, and clinical recurrence. METHODS: This work consisted of a retrospective study with cancer patients admitted to a university hospital between September 2018 and December 2019. Adults (age ≥ 18 years) who underwent at least one course of antibiotic therapy were included. CRP behavior over the first 7 days of treatment was classified as: i) good response: when the CRP value on the fifth day of therapy reached 50% or less of the peak value detected in the first 48 h of treatment, and ii) poor response: Maintenance, within the same interval, of a CRP value > 50% of the peak value in the first 48 h. The duration of antibiotic therapy was categorized as up to seven full days or more. Outcomes were assessed by events that occurred during the 30 days of hospitalization or until hospital discharge. PRIMARY OUTCOME: Clinical recurrence of the index infection. SECONDARY OUTCOMES: i) Death from any cause; ii) microbiological recurrence; iii) therapeutic response; iv) colitis associated with Clostridioides difficile; and v) isolation of multi-resistant bacteria, whether in clinical or surveillance samples. RESULTS: The final analysis consisted of 212 patients, with a median age (IQ) of 59.2 (48 - 67) years old and a predominance of females (65%), who were hypertensive (35%), smokers (21%), and diabetics (17.8%). There was no difference in clinical recurrence between the two groups (8.1% vs. 12.2%; p = 0.364), with a lower 30-day mortality in the good CRP response group (32.2% vs. 14.5%; p = 0.002). Despite the tendency towards a lower occurrence of other secondary outcomes in the good response group, these differences were not statistically significant. In the poor CRP response group, outcomes like clinical recurrence, mortality, and therapeutic response were significantly worse, regardless of the duration of antibiotic treatment. CONCLUSION: In this study, cancer patients with a good CRP response during antibiotic therapy presented lower mortality and a higher proportion of satisfactory therapeutic responses. CRP can be a useful tool when combined with other clinical information in optimizing the duration of antimicrobial treatment in a hospitalized cancer population.

Primary central nervous system lymphoma: Imaging features and differential diagnosis.

Primary central nervous system lymphoma (PCNSL) represents 5% of malignant primary brain tumors. The clinical presentation typically includes focal neurological symptoms, increased intracranial pressure, seizures, and psychiatric symptoms. Although histological examination remains the gold standard for diagnostic confirmation, non-invasive imaging plays a crucial role for the diagnosis. In immunocompetent individuals, PCNSL usually appears as a single, well-defined, supratentorial lesion with a predilection for periventricular areas, iso- or hypointense on T1- and T2-weighted magnetic resonance imaging, with restricted diffusion, slightly increased perfusion, and homogenous gadolinium-enhancement. Differential diagnoses include high-grade glioma and pseudotumoral demyelinating disease. In immunocompromised patients, PCNSL may present as multiple lesions, with a higher likelihood of hemorrhage and necrosis and less restricted diffusion than immunocompetent individuals. Differential diagnoses include neurotoxoplasmosis, progressive multifocal leukoencephalopathy, and cerebral abscess. Atypical forms of lymphoma are characterized by extra-axial lymphoma, lymphomatosis cerebri, and intravascular lymphoma. Extra-axial lymphoma presents as single or multiple extra-axial dural lesions with diffuse leptomeningeal contrast-enhancement. Lymphomatosis cerebri appears as an infiltrative and symmetric lesion, primarily affecting deep white matter and basal ganglia, appearing hyperintense on T2-weighted imaging, without significant contrast-enhancement or perfusion changes. Intravascular lymphoma presents as multiple rounded or oval-shaped "infarct-like" lesions, located cortically or subcortically. This study aims to highlight the imaging characteristics of PCNSL, focusing on magnetic resonance imaging and its differential diagnosis.