Advances in the field of developing biomarkers for re-irradiation: a how-to guide to small, powerful data sets and artificial intelligence.

Introduction: Patient selection remains challenging as the clinical use of re-irradiation (re-RT) increases. Re-RT data is limited to retrospective studies and small prospective single-institution reports, resulting in small, heterogenous data sets. Validated prognostic and predictive biomarkers are derived from large-volume studies with long-term follow-up. This review aims to examine existing re-RT publications and available data sets and discuss strategies using artificial intelligence (AI) to approach small data sets to optimize the use of re-RT data. Methods: Re-RT publications were identified where associated public data was present. The existing literature on small data sets to identify biomarkers was also explored. Results: Publications with associated public data were identified, with glioma and nasopharyngeal cancers emerging as the most common tumor sites where the use of re-RT was the primary management approach. Existing and emerging AI strategies have been used to approach small data sets including data generation, augmentation, discovery, and transfer learning. Conclusions: Further data is needed to generate adaptive frameworks, improve the collection of specimens for molecular analysis, and improve the interpretability of results in re-RT data.

Clinical and radiobiological consideration of cyclical hypofractionated radiation therapy also known as QUAD Shot for neglected skin cancer disfiguring the face of a non-compliant patient who was refusing surgery and protracted radiation therapy: case report

Although surgery is the mainstay of local treatment for skin cancer, definitive radiation therapy (RT) has been also applied for patients who are unable to tolerate surgery. Definitive RT regimens usually consist of daily treatment for 4–7 weeks. Such protracted daily RT regimens, however, would not be feasible for non-compliant patients or patients who are unable to make multiple daily trips for weeks. Without treatment, however, skin cancers can continuously progress and cause distressing symptoms. A cyclical hypofractionated RT (QUAD Shot: 14 Gy in 4 fractions, twice-daily treatments with 6 hours interval on 2 consecutive days) can be a practical RT regimen for those patients. In this report, we present the successful treatment course of repeated QUAD Shots in a 79-year-old patient with neglected skin cancer that was disfiguring his face yet declined definitive surgery and protracted RT. We also evaluated and compared biologically equivalent doses between QUAD Shots and conventionally fractionated protracted RT regimens.