Perforated appendicitis induced by pembrolizumab: a case report and review of the literature.

Monoclonal antibodies against programmed cell death protein 1 (PD-1) and PD-1 ligand 1 (PD-L1) are the main representatives in the field of immunotherapy and their indications are constantly increasing in medical oncology and hematology during the last decade. They are associated with long-lasting responses and an acceptable toxicity profile, although they may infrequently cause life-threatening complications requiring prolonged hospitalization or urgent interventions. With the current report, we present the case of a 75-year-old woman diagnosed with stage IV lung adenocarcinoma, who developed acute abdominal pain without preceding symptomatology while on pembrolizumab-pemetrexed maintenance treatment. A contained rupture of the appendix was found, for which she was managed conservatively. Subsequent endoscopic as well as histopathological findings from biopsies obtained via colonoscopy associated the clinical and imaging findings with grade 4 immune-mediated colitis. Interestingly, high-grade colitis is more frequent with anti-CTLA-4 agents in comparison to anti-PD-1 agents; moreover, most cases of anti-PD-1-mediated colitis present with preceding symptomatology (like diarrhea or vomiting), while cases or colonic perforation are extremely rare if ever described.

Case Report: Combination of Olaparib With Chemotherapy in a Patient With ATM-Deficient Colorectal Cancer.

Poly-ADP ribose polymerase (PARP) inhibitors are constantly increasing in their indications for use as anti-cancer treatment in various neoplasms, the majority of which are linked with BRCA deficiency. Preclinical data support the investigation of PARP inhibitors in other neoplasms exhibiting "BRCAness" or homologous recombination deficiency (HRD) as monotherapy as well as in combination with chemotherapy. With the current report we present the case of a heavily pretreated 55-year-old male patient diagnosed with stage IV ATM-deficient CRC, who was effectively treated with an off-label olaparib-irinotecan combination after exhaustion of all available treatment choices; furthermore, we discuss the existing data providing evidence for the use of PARP inhibitors in ATM-deficient CRC and encourage the implementation of next-generation sequencing (NGS) in patients with no other available treatment options.