UpToDate® and Oncology Times are collaborating to present select content synopses on "What's New in Oncology." UpToDate is an evidencebased, clinical support resource used worldwide by healthcare practitioners to make decisions at the point of care. For complete, current "What's New" content, or to become a subscriber for full content access, go to www.uptodate.com. "What's New" abstract information is free for all medical professionals. underrecognition of radiation dermatitis in patients with breast cancer undergoing radiotherapy (may 2022) Radiation dermatitis is the most common adverse effect of radiation therapy (RT) but may be underrecognized in some patients. In a cohort study that included nearly 10,000 patients from the United States with breast cancer who received RT and completed a patient-reported outcome questionnaire, 99 percent were matched to physician Common Terminology Criteria for Adverse Events (CTCAE) assessments [1]. Among over 5500 individuals reporting at least one RT symptom of breast pain, pruritus, edema, and fatigue, underrecognition by the physician occurred in 53 percent. Factors independently associated with underrecognition included age <50 years, being of Black or other than White ethnicity, receiving conventional fractionation, and male physician sex. Assessing subjective symptoms in patients undergoing RT may help reduce potential disparities in the diagnosis and management of radiation-related adverse effects, including dermatitis.immunotherapy for locally advanced rectal cancer with deficient mismatch repair (June 2022) Approximately 5 percent of rectal adenocarcinomas are deficient in DNA mismatch repair (dMMR), indicating potential responsiveness to immune checkpoint inhibitor immunotherapy. In a prospective study of 12 patients with stage II or III dMMR rectal cancer treated with dostarlimab monotherapy for 6 months, all 12 had a complete clinical response (radiographic and endoscopic), did not undergo chemoradiotherapy or surgery, and were free of residual or recurrent tumor with short-term follow-up (range 6 to 25 months) [2]. While this approach cannot yet be considered standard, individuals with dMMR tumors who place a high value on avoiding the long-term morbidity associated with surgery and pelvic radiation might choose this nonstandard approach if they are willing to accept the uncertainty of long-term outcomes, the small risk of fatal side effects from checkpoint inhibitors, and the need for very close follow-up.Pyelocalyceal mitomycin (Jelmyto) for low-grade upper tract urothelial carcinomas (may 2022) Pyelocalyceal mitomycin is used for patients with low-grade upper tract urothelial carcinoma (UTUC), but long-term efficacy data are lacking. In the final analysis of an open-label, single arm trial (OLYMPUS) of over 70 patients with treatment-naïve or recurrent low-grade UTUC, at median follow-up of one year, pyelocalyceal mitomycin demonstrated a complete response (CR) rate of 58 percent at three months [3,4]. Among the 41 patients with a CR, 23 (56 percent) had co...