Do vaginal recurrence rates differ among adjuvant vaginal brachytherapy regimens in early-stage endometrial cancer?

PurposeWe sought to retrospectively examine clinical outcomes for three adjuvant vaginal high-dose-rate (HDR) brachytherapy regimens after hysterectomy for early-stage endometrial cancer.MethodsIncluded were women of all ages from two independent hospital systems diagnosed with Stage I-II endometrial cancer of any grade between 2000 and 2016 who underwent hysterectomy followed by adjuvant vaginal cylinder HDR brachytherapy with either 7.0 Gy × 3 fractions prescribed to 0.5 cm vaginal depth, 6.5 Gy × 3 fractions prescribed to 0.5 cm vaginal depth, or 6.0 Gy × 5 fractions prescribed to the vaginal surface. Outcomes included vaginal recurrence (VR), pelvic recurrence, distant recurrence, locoregional recurrence, recurrence-free survival, and overall survival.ResultsOf the 348 women, 45 (13%) received 7.0 Gy × 3 fractions, 259 (74%) received 6.5 Gy × 3 fractions, and 44 (13%) received 6.0 Gy × 5 fractions. Women receiving 5-fraction brachytherapy were more likely to be younger with a higher performance status. At a median follow-up of 4.5 years, VR rates were 2.2%, 0.8%, and 4.5%, respectively. Multivariate analysis revealed no significant differences in the risks for VR among brachytherapy regimens. Risks for VR, pelvic recurrence, distant recurrence, locoregional recurrence, recurrence-free survival, and overall survival did not differ between propensity score–matched five- and 3-fraction brachytherapy cohorts.ConclusionsVR rates after hysterectomy and adjuvant vaginal brachytherapy for early-stage endometrial cancer were low and not significantly different by HDR dose fractionation.     

A modified technique for high-dose-rate intracavitary brachytherapy in advanced cancer of the cervix

PURPOSE: To develop a modified technique for high-dose-rate intracavitary brachytherapy in cervical cancer stage IIIb. METHODS AND MATERIALS: Cervical carcinoma FIGO Stage III accounts for > 60% of all cervical cancers with radiation being the mainstay of treatment for most patients. After external beam radiation therapy (EBRT), the cervix is often flush with the vagina and the shape of the vagina may be conical with its apex at the external os level. All patients receive 2 applications with HDR brachytherapy. At the first application after the placement of the central tandem, only one ovoid is inserted and the other ovoid is replaced by a rubber tube, and the applicator assembly is fixed as usual. The contralateral ovoid is inserted at the subsequent application. RESULTS: To date, 21 locally advanced cervical cancer patients have been treated using this technique. In these patients, the mean dose to right and left Point A was 93% (range, 86-100%; median, 93%) and 95% (range, 90-100%; median, 95%), respectively. The variation of doses to the contralateral Point A was 1-14%. The mean dose to the rectal and bladder mucosa was 62% (range, 43-80%; median, 64%) and 80% (range, 50-110%; median, 71%), respectively. CONCLUSION: This modified HDR intracavitary technique may prove an alternative for centers where interstitial brachytherapy for cancer of the cervix is not available.     

An age-corrected matched-pair study of erectile function in patients treated with dose-escalated adaptive image-guided intensity-modulated radiation therapy vs. high-dose-rate brachytherapy for prostate cancer

PurposeTo compare erectile dysfunction (ED) after adaptive dose-escalated image-guided intensity-modulated radiotherapy (IG-IMRT) and high-dose-rate interstitial brachytherapy (HDR) monotherapy.Methods and MaterialsLow- and intermediate-risk prostate cancer patients treated with IG-IMRT or HDR were matched on pretreatment ED, age, Gleason score, T-stage, and prostate specific antigen. Patients who received androgen deprivation therapy were excluded. ED was graded by Common Terminology Criteria for Adverse Events v4. Actuarial rates of ED were computed by the Kaplan–Meier method.ResultsThere were 384 patients with median followup of 2.0 years (0.5–6.1) for IG-IMRT and 2.0 years (0.5–8.7) for HDR. The median IG-IMRT dose was 75.6 Gy and HDR dose 38 Gy in four fractions. For patients with no pretreatment ED, actuarial rates of requiring intervention (Grade ≥2 ED) at 3 years were 31% for IG-IMRT and 19% for HDR (p = 0.23), and impotence despite medical intervention (Grade 3) were 0% for IG-IMRT and 6% for HDR (p = 0.06). For patients with Grade 1 pretreatment ED, Grade ≥2 ED at 3 years were 47% for IG-IMRT and 34% for HDR (p = 0.79), and Grade 3 ED were 15% in both groups (p = 0.59). For patients with Grade 2 pretreatment ED, Grade 3 ED at 3 years were 22% for IG-IMRT and 37% for HDR (p = 0.70). No variables were predictive of Grade ≥2 ED following treatment.ConclusionsRates of ED requiring medical intervention for both IG-IMRT and HDR are low and equivalent. Even patients with ED before treatment are likely to maintain potency with medication use at 3 years following treatment.     

Qualitative dosimetric and radiobiological evaluation of high - dose - rate interstitial brachytherapy implants

Radiation quality indices (QI), tumor control probability (TCP), and normal tissue complication probability(NTCP) were evaluated for ideal single and double plane HDR interstitial implants. In the analysis, geometrically-optimized at volume (GOV) treatment plans were generated for different values of inter-source-spacing (ISS) within the catheter, inter-catheter-spacing (ICS), and inter-plane-spacing (IPS) for single - and double - plane implants. The dose volume histograms (DVH) were generated for each plan, and the coverage volumes of 100%, 150%, and 200% were obtained to calculate QIs, TCP, and NTCP. Formulae for biologically effective equivalent uniform dose (BEEUD), for tumor and normal tissues, were derived to calculate TCP and NTCP. Optimal values of QIs, except external volume index (EI), and TCP were obtained at ISS = 1.0 cm, and ICS = 1.0 cm, for single-plane implants, and ISS = 1.0 cm, ICS = 1.0 cm, and IPS = 0.75 to 1.25 cm, for double - plane implants. From this study, it is assessed that ISS = 1.0 cm, ICS = 1.0 cm, for single - plane implant and IPS between 0.75 cm to 1.25 cm provide better dose conformity and uniformity.     

An optimized SpCas9 high-fidelity variant for direct protein delivery

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