Non-melanoma skin cancers (NMSCs) are a significant cause of morbidity and mortality; their incidence is increasing most in older patients. NMSCs have traditionally been treated with surgical excision, curettage, Mohs micrographic surgery (MMS), and superficial radiotherapy (SRT). Image-guided SRT (IGSRT) is a treatment option for poor surgical candidates or patients with low- or high-risk, early-stage NMSC who prefer to avoid surgery. This large retrospective cohort study compared 2-, 4-, and 6-year freedom from recurrence in biopsy-proven NMSC lesions treated with IGSRT (n = 20,069 lesions) between patients aged < 65 years (n = 3158 lesions) and ≥65 years (n = 16,911 lesions). Overall freedom from recurrence rates were 99.68% at 2 years, 99.57% at 4 years, and 99.57% at 6 years. Rates did not differ significantly by age (p = 0.8) nor by sex among the two age groups (p > 0.9). There was a significant difference in recurrence among older patients when analyzed by stage (p = 0.032), but no difference by stage in younger patients (p = 0.7). For early-stage NMSCs, IGSRT is a clinically equivalent alternative to MMS and statistically significant in superiority to non-image-guided SRT. This study demonstrates that there is no significant effect of age on 2-, 4-, or 6-year freedom from recurrence in patients with IGSRT-treated NMSC.

Non-melanoma skin cancers (NMSCs), including basal cell carcinoma (BCC) and squamous cell carcinoma (SCC), are highly prevalent and a significant cause of morbidity. Image-guided superficial radiation therapy (IGSRT) uses integrated high-resolution dermal ultrasound to improve lesion visualization, but it is unknown whether efficacy varies by histology. This large retrospective cohort study was conducted to determine the effect of tumor histology on freedom from recurrence in 20,069 biopsy-proven NMSC lesions treated with IGSRT, including 9928 BCCs (49.5%), 5294 SCCs (26.4%), 4648 SCCIS cases (23.2%), and 199 lesions with ≥2 NMSCs (1.0%). Freedom from recurrence at 2, 4, and 6 years was 99.60%, 99.45%, and 99.45% in BCC; 99.58%, 99.49%, and 99.49% in SCC; and 99.96%, 99.80%, and 99.80% in SCCIS. Freedom from recurrence at 2, 4, and 6 years following IGSRT did not differ significantly comparing BCC vs. non-BCC or SCC vs. non-SCC but were slightly lower among SCCIS vs. non-SCCIS (p = 0.002). There were no significant differences in freedom from recurrence when stratifying lesions by histologic subtype. This study demonstrates that there is no significant effect of histology on freedom from recurrence in IGSRT-treated NMSC except in SCCIS. These findings support IGSRT as a first-line therapeutic option for NMSC regardless of histology.

Non-melanoma skin cancers (NMSCs), including basal cell carcinoma (BCC) and squamous cell carcinoma (SCC), are highly prevalent and a significant cause of morbidity. Image-guided su-perficial radiation therapy (IGSRT) uses integrated high-resolution dermal ultrasound to improve lesion visualization, but it is unknown whether efficacy varies by histology. This large retro-spective cohort study was conducted to determine the effect of tumor histology on freedom from recurrence in 20,069 biopsy-proven NMSC lesions treated with IGSRT, including 9,928 BCC (49.5%), 5,294 SCC (26.4%), 4,648 SCCIS (23.2%), and 199 lesions with ≥2 NMSCs (1.0%). Freedom from recurrence at 2, 4, and 6 years was 99.60%, 99.45%, and 99.45% in BCC; 99.58%, 99.49%, and 99.49% in SCC; and 99.96%, 99.80%, and 99.80% in SCCIS. Freedom from recurrence at 2, 4, and 6 years following IGSRT did not differ significantly comparing BCC vs. non-BCC or SCC vs. non-SCC but were slightly lower among SCCIS vs. non-SCCIS (p = 0.002). There were no significant differences in freedom from recurrence when stratifying lesions by histologic subtype. This study demonstrates that there is no significant effect of histology on freedom from recurrence in IGSRT-treated NMSC except in SSCIS. These findings support IGSRT as a first-line therapeutic option for NMSC regardless of histology.