This prospective study evaluated the clinical implementation value of an optical surface monitoring system (OSMS) in the radiotherapy setup for patients with vulvar cancer, compared to standard laser-based setup

This was a prospective single-centre trial to investigate the value of OSMS, and we hypothesized that using OSMS would reduce setup error in vulvar cancer treatment compared to a standard laser-based setup. A dose of 45 Gy was delivered to the clinical target volume with intensity-modulated radiation therapy (IMRT) for a total of 25 fractions, followed by 16 to 24 Gy of local electron beam supplementation. Marks were placed on each patient's skin to align the room lasers for presetup, and the setup was completed with information from the OSMS. The deviation values in three translation directions, lateral (Lat), longitudinal (Lng), and vertical (Vrt), and three rotation directions, Rtn (rotation along the z-axis), Pitch (rotation along the x-axis), and Roll (rotation along the y-axis) were obtained. The absolute values of setup error and error distribution of the standard laser-based setup and OSMS were compared.

Inclusion Criteria:

1. Patients must be informed of the investigational nature of this study and give written informed consent before treatment.
2. Age ≥18 years and ≤ 85 years.
3. Patients with histologically confirmed vulvar cancer.
4. No evidence of distant metastasis on CT, MRI or positron emission tomograph (PET)/CT.
5. No contraindications to CT scanning.
6. Indications for radiotherapy for vulvar cancer.
7. Adequate marrow: neutrophile granulocyte count ≥1.5*10^9/L, hemoglobin ≥ 80 g/L, platelet count ≥100*10^9/L.
8. Normal liver and kidney function: Creatinine (Cr) < 1.5 mg/dl, Alanine Aminotransferase (ALT), Aspartate Aminotransferase (AST) < 2*upper limit of normal (ULN).

Exclusion Criteria:

1. No pathological diagnosis.
2. Remote metastasis.
3. Anticipated intolerance of pelvic radiotherapy.
4. Any severe disease which may bring unacceptable risk or affect the compliance of the trial, for example, unstable cardiac disease requiring treatment, renal disease, chronic hepatitis, diabetes with poor control, and emotional disturbance.