The impact of tumor size and histology on local control when utilizing high-dose-rate interstitial brachytherapy for gynecologic malignancies.

OBJECTIVE: To report long-term results of an outpatient template-based high-dose-rate interstitial brachytherapy (HDR ISBT) program for the treatment of gynecologic malignancies. METHODS: Patients treated between 2006 and 2020 at an academic hospital with outpatient template based HDR ISBT without spinal or general anesthesia were reviewed. Patients who had previously received HDR ISBT were excluded. Baseline patient, tumor, and treatment characteristics, such as tumor size, histology, and/or total EQD2 including prior external beam radiation therapy (EBRT) were recorded. Local control and overall survival were estimated using the Kaplan-Meier method, and factors associated with local control and overall survival were evaluated using Cox regression analyses. RESULTS: 150 patients received HDR ISBT for a gynecologic tumor and the median follow-up time was 2.98 years (0.89-4.82). Of those, 74/150 (49%) were treated definitively, 69/150 (46%) were treated for tumor recurrence/persistence, and 7/150 (5%) were treated for durable palliation. Median tumor size was 3.00 cm (1.50-4.00). 124/150 (83%) patients received EBRT prior to HDR ISBT. Median HDR ISBT dose was 18 Gy delivered in eight fractions. Local control was 71% (64%-79%), 58% (50%-68%), and 57% (48%-67%) at one, three, and five years, respectively. On multivariate analysis, non-endometrial adenocarcinoma histology (HR = 2.423, 95% CI = 1.011-5.808, p = 0.047) and tumor size ≥ 3 cm (HR = 2.903, 95% CI 1.053-3.441, p = 0.033) were associated with lower local control. CONCLUSIONS: The majority of patients who received outpatient-based twice daily HDR ISBT had long-term local control. Larger tumor size and non-endometrial adenocarcinoma histology were detrimental to local control.

Predictors of acute throat or esophageal patient reported pain during radiation therapy for head and neck cancer.

BACKGROUND AND PURPOSE: Acute pain during weekly radiotherapy (RT) to the head and neck is not well characterized. We studied dose-volume metrics and clinical variables that are plausibly associated with throat or esophageal pain as measured with a weekly questionnaire during RT. MATERIALS AND METHODS: We prospectively collected weekly patient-reported outcomes from 122 head and neck cancer patients during RT. The pain score for each question consisted of a four-level scale: none (0), mild (1), moderate (2), and severe (3). Univariate and multivariate ordinal logistic regression analyses were performed to investigate associations between both esophageal and throat pain and clinical as well as dosimetric variables. RESULTS: In multivariate analysis, age was significantly associated with both types of pain, leading to odds ratio (OR) = 0.95 (p = 0.008) and OR = 0.95 (p = 0.007) for esophageal and throat pain, respectively. For throat pain, sex (OR = 4.12; p = 0.010), with females at higher risk, and fractional organ at risk (OAR) mean dose (OR = 3.30; p = 0.014) were significantly associated with throat pain. CONCLUSIONS: A fractional OAR mean dose of 1.1 Gy seems a reasonable cutoff for separating no or mild pain from moderate to severe esophageal and throat pain. Younger patients who received RT experienced more esophageal and throat pain. Females experienced more throat pain, but not esophageal pain.

Outpatient-based high-dose-rate interstitial brachytherapy for gynecologic malignancies.

PURPOSE: To evaluate outpatient-based high-dose-rate (HDR) interstitial brachytherapy (ISBT) in the treatment of gynecologic malignancies. METHODS AND MATERIALS: Between December 2006 and July 2012, 50 patients were treated with twice-daily outpatient-based HDR iridium-192 ISBT at our institution. Thirty-two patients had vaginal cancers, 13 vulvar, 3 urethral, and 2 cervical cancers. The most common histologies were squamous cell carcinoma (58%) and endometrioid adenocarcinoma (26%). Twenty-six patients were treated with definitive radiation therapy with or without platinum-based chemotherapy, 16 were treated for recurrent disease, 5 were treated in the postoperative setting, and 3 were treated palliatively. Forty patients received external beam radiation therapy before ISBT. RESULTS: Median followup was 13.7 months. Median interstitial dose was 18 Gy in 2.25 Gy twice-daily fractions prescribed to the implant volume. Median external beam dose was 50.4 Gy in 1.8 Gy daily fractions prescribed to the primary disease site. Eight patients (16%) were seen in the emergency room or were admitted to the hospital during treatment. Six patients (17%) experienced significant complications after treatment (3 ulcerations at the primary site, 1 vaginal necrosis, 1 vaginal abscess, and 1 patient with urinary obstruction). Larger volume encompassing 100% of the prescribed dose was correlated with significant complications on multivariate analysis (p = 0.039). Actuarial local control at 1 year was 72%, with univariate analysis demonstrating worse local control for nonendometrioid adenocarcinoma compared with squamous cell carcinoma (20% vs. 84%, p = 0.044). CONCLUSIONS: Outpatient-based HDR ISBT is feasible and safe, with toxicity and local control rates consistent with historical outcomes.