Image-Guided Radiation Therapy Is Equally Effective for Basal and Squamous Cell Carcinoma

Area of Science:

• Dermatology
• Radiation Oncology
• Oncology

Background:

• Non-melanoma skin cancers (NMSCs), including basal cell carcinoma (BCC) and squamous cell carcinoma (SCC), are common and cause significant morbidity.
• Image-guided superficial radiation therapy (IGSRT) utilizes dermal ultrasound for enhanced lesion visualization.
• The impact of tumor histology on IGSRT efficacy for NMSCs remains unclear.

Purpose of the Study:

• To evaluate the effect of tumor histology on the freedom from recurrence in NMSC patients treated with IGSRT.
• To compare recurrence rates across different NMSC histologies, including BCC, SCC, and SCCIS.
• To determine if IGSRT is a suitable first-line therapy irrespective of NMSC histology.

Main Methods:

• A large retrospective cohort study of 20,069 biopsy-proven NMSC lesions treated with IGSRT.
• Analysis of freedom from recurrence at 2, 4, and 6 years for BCC, SCC, and SCCIS.
• Statistical comparison of recurrence rates between different histologic groups and non-BCC/non-SCC controls.

Main Results:

• Overall freedom from recurrence at 6 years was high across all histologies (BCC: 99.45%, SCC: 99.49%, SCCIS: 99.80%).
• No significant differences in freedom from recurrence were observed when comparing BCC vs. non-BCC or SCC vs. non-SCC.
• Slightly lower freedom from recurrence was noted for SCCIS compared to non-SCCIS (p = 0.002), but no significant differences existed when stratifying by specific histologic subtypes.

Conclusions:

• Histology does not significantly affect freedom from recurrence in IGSRT-treated NMSCs, with the exception of SCCIS.
• IGSRT demonstrates consistent efficacy across various NMSC histologies.
• These findings support IGSRT as a reliable first-line therapeutic option for NMSC, regardless of histologic subtype.