Background: The 21^st Century Cures Act in 2016 enhanced the FDA’s ability to include the use of real-world data (RWD) and consideration of RWE in the development and approval of new medical products. Currently, limited assessments of the use of RWE in FDA approved oncology product reviews exist in the literature. This study was conducted to determine how RWE was used in FDA decisions for oncology drug approvals between 2015 and 2022. Methods: A systematic review of FDA submission documents and product labels available on the FDA website from 2020 to 2022, in addition to an exhaustive manual search of grey literature and the results of a targeted literature search from 2015 to 2019 were used to identify RWE that were included in FDA submission documents and in approved product labels. Results: In total, 124 oncology product evaluations were reviewed in the 2020 to 2022 literature search. Twenty-nine oncology product NDAs and BLAs included RWE to support efficacy, safety, or indication, of which the majority (n=26) ultimately had RWE accepted as evidence by the FDA for the submission. In these cases, RWE was used to add context (n=16), to support the indication or safety (n=7), to provide substantial basis for indication or safety (n=2), as a statistical comparison (n=2), or for informational purposes only (n=1). Feedback from the FDA reviewers for reasons RWE studies were not considered during product approval reviews included methodology issues, sample size concerns, and omission of patient level data. Ultimately, across the 2015 to 2019 targeted literature review and the 2020 to 2022 FDA submission document review, 6 oncology product labels incorporated RWE: palbociclib, uridine triacetate, lutetium Lu 177 DOTATATE, bevacizumab-adcd, naxitamab-gqgk, and decitabine/cedazuridine. RWE was used to support the initial indication for the majority of products (n=5) and also supported label expansion (n=1). RWE was incorporated in the product label postmarketing experience section (n=3), the clinical studies section (n=2), and the warnings/precautions section (n=1). Conclusions: These results suggest that RWE has become an important part of regulatory decision-making for oncology drug approval. Twenty-six of 29 RWE studies were accepted as evidence for the submission. For the 6 oncology products that include RWE in the product label, RWE was most frequently used to support the initial indication and was included in the postmarketing experience section. These examples show consistent use of RWE since the approval of the 21st Century Cares Act and provide evidence of a promising new direction with the creation of the FDA guideline/program for RWE.