Chest pain and eosinophilia in a middle-aged female caused by hookworm infection: a case report.

An estimated 81,610 new diagnoses and 14,390 deaths are expected from kidney cancer this year in the U.S., representing a significant disease burden despite modern advancements in detection and treatment. Renal cell carcinoma (RCC) arising from the renal cortex is the most common kidney malignancy, accounting for approximately 90% of cases. RCC is itself heterogeneous, with most cases being the clear cell RCC subtype (70%-75%), followed by papillary (10%-15%), chromophobe (5%), and rare other subtypes. Metastatic RCC is generally lethal; however, RCC that is clinically localized to the kidney is usually cured using extirpative therapy, with approximately one in four patients experiencing metastatic relapse. In addition to tumor stage and grade, a key prognostic factor for localized RCC patients is tumor size at diagnosis. Small renal masses (SRM, SRMs), defined as renal cortical tumors up to 4 cm, have an especially outstanding prognosis, due to their remarkably indolent behavior that includes a slow growth rate (GR), frequent growth cessation, and rare metastatic potential. The rising incidence of RCC in recent decades is likely attributable to the increased incidental detection of smaller asymptomatic kidney tumors, resulting from high contemporary usage of cross-sectional imaging. Accordingly, SRMs now make up approximately half of all new RCC diagnoses, and their overtreatment represents a significant healthcare challenge. Given increased awareness of their clinical indolence, we have seen a change in the paradigm of how SRMs are managed over the past two decades, both in the U.S. and globally. Historically, surgical resection with partial or radical nephrectomy has provided the mainstay of treatment for patients with SRMs. However, as with any major operation, this surgery can incur significant morbidity, including long-term sequelae or even rare mortality, making it hard to justify in light of the non-aggressive nature of SRMs. While thermal ablation has emerged as a less invasive treatment option for SRMs, procedural morbidity still occurs, and oncologic control is inferior to resection; hence, surgery remains the current treatment of choice. Given the clinical indolence of SRMs and potential morbidity of current treatment options, active surveillance (AS) has gained popularity as a first-line alternative to immediate treatment in select SRM patients. In contrast to observation (i.e., watchful waiting), which defers curative treatment, AS management includes a plan upon tumor progression for delayed intervention (DI) with curative intent. However, many questions remain as to what constitutes optimal AS practice, particularly for patient selection, monitoring protocols, and the identity of progression triggers for DI. The current review provides an evidence-based perspective on these and other select controversies in contemporary AS management for SRM patients. Despite increasing popularity, AS utilization in SRM patients still varies dramatically across practices. While only a minority of SRM patients (~10%-20%) undergo AS on a national level, some academic U.S. centers are now utilizing AS even more often than immediate treatment. For example, per the 8-year experience reported out of Roswell Park Cancer Center, > 95% of all SRM patients were recommended and underwent AS, with immediate treatment reserved only for the rare patient subset with progression criteria already apparent at presentation. Similarly, 61% of SRM patients in the multi-center Delayed Intervention and Surveillance for Small Renal Masses (DISSRM) registry have elected AS since 2009, including higher rates in more recent years. Such variation is also prevalent within the community. Recent statewide population data from the Michigan Urological Surgery Improvement Collaborative (MUSIC) revealed stark differences in AS or observation adoption across more than a dozen academic or private urology practices, with some practices opting for AS/observation in more than 50% of SRM patients, compared to minimal AS/observation utilization (< 5%) for other practices. While MUSIC oncologic outcomes await maturity, both the DISSRM consortium and Roswell Park have reported low metastasis rates of < 1% despite their high AS adoption. Given this outstanding outcome, albeit from a limited number of centers, such dramatic variation in AS adoption raises critical questions about what drives AS patient selection and whether AS is being underutilized in specific settings.