Early Prostate-Specific Antigen Kinetics for Low- and Intermediate-Risk Prostate Cancer Treated With Definitive Radiation Therapy.

PURPOSE: This study used a patient-specific model to characterize and compare ideal prostate-specific antigen (PSA) kinetics for low- and intermediate-risk prostate cancer after definitive radiation treatment with conventionally fractionated, hypofractionated, stereotactic body radiation therapy, or brachytherapy, both high-dose and low-dose rate. METHODS AND MATERIALS: This retrospective analysis includes low- and intermediate-risk patients with prostate cancer treated between 1998 and 2018 at an National Cancer Institute-designated comprehensive cancer center. Demographics and treatment characteristics were prospectively collected. Patients had at least 2 PSA measurements within 24 months of treatment and were free from biochemical recurrence. The incidence of, time to, and risk factors for PSA nadir (nPSA) and bounce (bPSA) were analyzed at 24 months after radiation therapy. Ideal PSA kinetics were characterized for each modality and compared. RESULTS: Of 1042 patients, 45% had low-risk cancer, 37% favorable intermediate risk, and 19% unfavorable intermediate risk. nPSAs were higher for ablative modalities, both as absolute nPSA and relative to initial PSA. Median time to nPSA ranged from 14.8 to 17.1 months. Over 50% treated with nonablative therapy (conventionally fractionated, hypofractionated, and low-dose rate) reached an nPSA threshold of ≤0.5 ng/mL compared with 23% of stereotactic body radiation therapy and 33% of high-dose rate cohorts. The incidence of bPSA was 13.3% and not affected by treatment modality, Gleason score, or prostate volume. PSA decay rate was faster for ablative therapies in the 6- to 24-month period. CONCLUSIONS: Analysis of PSA within 24 months after radiation therapy revealed ablative therapies are associated with a latent PSA response and higher nPSA. Multivariable logistics modeling revealed younger age, initial PSA above the median, presence of bPSA, and ablative therapy as predictors for not achieving nPSA ≤0.5 ng/mL. PSA decay rate appears to be faster in ablative therapies after a latent period. Understanding the different PSA kinetic profiles is necessary to assess treatment response and survey for disease recurrence.

Vulvar Melanoma with Isolated Metastasis to the Extraocular Muscles: Case Report and Brief Literature Review.

BACKGROUND/AIM: Orbital metastasis of systemic cancer is exceedingly rare. This is a case report of a patient treated for locally recurrent vulvar melanoma who later presented with unilateral proptosis and was found to have an isolated biopsy-proven extraocular muscle metastasis. PATIENTS AND METHODS: A 94-year-old female with locally recurrent vulvar melanoma presented with eye discomfort and blurry vision. Patient underwent histopathological, genetic, and imaging studies. RESULTS: All prior work-up, including brain MRI and PET/CT, was negative for disease elsewhere from local recurrence. Orbital MRI demonstrated a mass involving the extraocular muscle, and immunohistochemistry staining of biopsy was consistent with metastasis. The patient underwent radiation therapy and tolerated treatment well. CONCLUSION: This is the first reported case of vulvar melanoma with extraocular muscle metastasis. The absence of findings on imaging as part of the staging work-up underscores the importance of considering extraocular muscle (EOM) metastasis as a differential for patients with vulvar melanoma who present with proptosis.