Review of brachytherapy clinical trials: a cross-sectional analysis of ClinicalTrials.gov

INTRODUCTION

Characterizing the landscape of clinical trials including brachytherapy can provide an overview of the current status and research trends which may guide further areas of investigation.

METHOD

We queried 449,849 clinical trials from the ClinicalTrials.gov registry using brachytherapy-related keywords from 1980 to 2023, yielding 245 multi-arm and 201 single-arm, brachytherapy trials. Multi-arm and single-arm brachytherapy trials were compared using 12 trial protocol elements.

RESULTS

The number of trials including brachytherapy has increased over time, with over 60% of trials registered in 2010 onwards. The majority of clinical trials were Phase 2 or 3, evaluated both safety and efficacy, and were funded by academic sponsors. The most common tumor sites evaluated in brachytherapy clinical trials include prostate, cervix, liver, endometrium, and breast.

CONCLUSION

There remains continued interest in clinical trials including brachytherapy focused on evaluation of novel delivery systems, treatment planning, and new indications. More brachytherapy clinical trials are needed to define the optimal clinical utilization and advance prospective research in this field.

Clinical Validation of HPV ctDNA for Early Detection of Residual Disease Following Chemoradiation in Cervical Cancer

PURPOSE/OBJECTIVE(S)

Despite chemoradiation (CRT), 30-40% of patients with locally advanced cervical cancer relapse. Most cases are caused by human papilloma virus (HPV), and HPV circulating tumor DNA (ctDNA) may identify patients at highest risk of relapse. Our previous pilot study showed that detectable HPV ctDNA at the end of CRT is associated with inferior progression-free survival (PFS) using digital polymerase chain reaction (dPCR), and that a next generation sequencing approach (HPV-seq) may outperform dPCR. We hypothesized that HPV ctDNA may identify cervical cancer patients at increased risk of relapse following CRT and aimed to prospectively validate HPV ctDNA as a tool for early detection of residual disease.

MATERIALS/METHODS

This prospective, multicenter validation study accrued 70 patients with HPV+ stage IB-IVA cervical cancer treated with definitive CRT from 2017-2022. Patients underwent phlebotomy at baseline, end of, 4-6 weeks and 3 months post CRT for HPV ctDNA levels. HPV genotyping was performed on the baseline plasma sample using HPV-seq. HPV genotype-specific DNA levels in plasma were quantified using both dPCR and HPV-seq. PFS was estimated using the Kaplan-Meier method and compared using the log rank test. Multivariable Cox regression analyses incorporating stage and HPV ctDNA detectability assessed independent prognostic factors associated with PFS.

RESULTS

At the time of abstract, results for 67 patients were available. The majority had squamous histology (84%) and stage IIB (36%) or IIIC1 (25%) disease. HPV genotyping using HPV-seq revealed 54% (36/67) of cases harboring HPV-16, and 46% harboring other HPV types: 15 HPV-18; 5 HPV-59; 2 HPV-31; 2 HPV-33; 2 HPV-52; 1 each HPV-39, HPV-45, HPV-53, HPV-58, and HPV-82. With a median follow up of 2.2 (range 0.4 - 5.2) years, there were 21 PFS events. Most recurrences (14/21) were distant and/or paraaortic; 4 local and nodal/distant; 2 pelvic nodal; and 1 local. Patients with detectable HPV ctDNA on dPCR at the end of, 4-6 weeks and 3 months post CRT had significantly worse 2-year PFS compared to those with undetectable HPV ctDNA (78 vs 52%, p = 0.04; 82 vs 26%, p < 0.001; and 80 vs 23%, p = < 0.001, respectively). HPV-seq showed similar results (87 vs 55%, p = 0.02; 81 vs 45%, p = 0.003; and 84 vs 31%, p = < 0.001, respectively). On multivariable analyses, detectable HPV ctDNA on dPCR and HPV-seq remained independently associated with inferior PFS (see table).

CONCLUSION

HPV-seq enables HPV genotyping directly from plasma in locally advanced cervical cancer. Persistent HPV ctDNA following CRT is independently associated with inferior PFS in this prospective validation study. HPV ctDNA testing can be used to identify, as early as at the end of CRT, patients at high risk of recurrence in future treatment intensification trials.

Real-World Experience of Intensity Modulated Radiation Therapy and Concurrent Chemotherapy for Anal Cancer with Long-Term Follow up and Clinical Outcomes

PURPOSE/OBJECTIVE(S)

The standard treatment for epidermoid anal cancer (AC) is concurrent chemoradiation (CRT). Here we present real world evidence of the safety and outcomes of AC patients managed by IMRT and concurrent chemotherapy at a single academic cancer center.

MATERIALS/METHODS

We retrospectively reviewed the outcomes of 180 AC patients treated with definitive CRT between 2011 and 2018. Patients were managed according to a prospectively designed protocol of IMRT with radiation dose escalated according to tumor stage: 50.4, 55.8 and 63 Gy for T1, T2 and T3/T4 disease respectively, and 36 Gy for elective nodal RT. Involved nodes were given the same dose based on T category. Concurrent chemotherapy consisted of two cycles of mitomycin C (MMC, 12 mg/m2) and 5-fluorouracil (5FU, 1000 mg/m2/day x 4 days) given on week 1 and 5. There was no planned treatment break. Univariate and multivariate analysis for outcomes were performed using Cox proportional hazard method and likelihood ratio statistics. Overall survival (OS) disease free (DFS), colostomy-free survival (CFS) and local failure rates (LFR) were described by Kaplan-Meier methods.

RESULTS

There were 128 female and 52 male patients with a median age of 64 (IQR 55-74). The median size of the primary was 4.0 cm (0.6-11.0 cm). There were 18 T1, 91 T2, 38 T3 and 33 T4 lesions; 50.6% (91/180) of the patients had N0 disease. Thirteen (7.2%) did not receive concurrent chemotherapy, and 16 (8.9%) failed to complete treatment as planned. Forty-three (23.9%) patients had a treatment gap >5 (6-33) days. Eighteen of 147 (12%) with T1-3 disease failed locally, LF was observed in 13/33 (39%) T4 lesions (P = 0.0002). The 5-year OS, DFS, CFS and LFR were 85.1%, 75.6%, 87.6% and 15.5% respectively. On multivariate analysis, increasing age and N+ disease were significant for worse OS, and increasing size of the primary tumor was the only significant factor for worse DFS, CFS and LFR. Grade ≥3 acute toxicities were observed in 42.8% of patients, with grade ≥3 neutropenia and febrile neutropenia observed in 18.9% and 13.9% of patients respectively. Six patients (3.3%) died of acute toxicities. Thirteen (7%) patients experienced grade ≥3 late toxicities.

CONCLUSION

Size of the primary appears to be the most important determinant of outcome following standard CRT using IMRT for AC. Despite IMRT, almost 1 in 4 patients required a treatment break, and over 40% experienced grade ≥3 acute toxicities including neutropenia and febrile neutropenia. Future studies with RT dose escalation or de-escalation, stratifying patients based on tumor size, HPV status and molecular markers are necessary to improve outcomes and decrease treatment related toxicity.

Risk-adjusted chemoradiation according to human papilloma viral status for anal cancer: a pilot study

Background and purpose

HPV-associated or positive (HPV+) anal cancer patients may have better outcome compared to those with HPV negative (HPV-) disease. We report a planned interim analysis of a prospective registry study that tailors chemoradiation (CRT) for anal cancer according to HPV status.

Materials and methods

HPV+ patients received de-escalated radiation doses of 45, 50.4 and 55.8 Gy, while HPV- received 50.4, 55.8 and 63 Gy for T1, T2 and T3/T4 disease respectively. Chemotherapy consisted of a single dose of mitomycin-C and oral capecitabine on days of RT. All patients were planned by VMAT following CT, PET/CT and MR simulation. This cohort (n = 24) had a minimum 24-month follow-up. Disease free survival (DFS) and local failure rates (LFR) were compared with 180 patients managed by standard CRT (2 cycles of mitomycin-C and 5-fluorouracil, radiation doses 50.4-63 Gy based on T-category) from 2011-2018. Propensity score comparison was performed using a retrospective to prospective 2 to 1 match based on tumor size and N-category.

Results

In the HPV+ cohort (n = 20), there were 2 local failures. Two of 4 HPV- patients failed locally. The 30-month DFS and LFR were 79% and 17% respectively. Similar DFS and LFR were observed in the retrospective (80% and 15% respectively) and matched patients (76% and 16% respectively). No grade ≥3 neutropenia and febrile neutropenia were observed in the registry cohort whereas 19% and 14% respectively were seen in the retrospective patients.

Conclusion

De-escalation of CRT for HPV+ anal cancer may result in decreased acute toxicities and similar cancer outcomes compared to standard CRT.

Organ and Function Preservation in Gastrointestinal Malignancies

Radiation plays an important role in organ preservation for gastrointestinal malignancies, with a watch and wait strategy enabling surgery to be avoided in patients who are not suitable or who are refusing surgery. Brachytherapy boost allows the radiation dose to be escalated, which plays a pivotal role in the successful outcome of achieving organ preservation. Here we describe the role of brachytherapy in two common gastrointestinal malignancies (oesophagus and rectum). Their indications and how the brachytherapy procedures are carried out, together with the dose and fractionation commonly used are discussed. The use of brachytherapy needs to be included in the training curriculum at all academic centres so that its use is developed by the newer generation of radiation oncologists. Its current non-use due to bias, lack of training and availability is no longer justified, given the overwhelming published evidence for the role of brachytherapy to improve organ preservation for both radical treatment and palliation in gastrointestinal malignancies.

Opioid consumption and pain in patients with gynecological cancer who underwent spinal anesthesia vs. general anesthesia for interstitial brachytherapy

AIMS

Interstitial brachytherapy (ISBT) is an effective option for delivering conformal high dose radiation to the target volume with better organ-at risk sparing but is thought to be more invasive and painful than other methods. This study investigated pain levels and opioid consumption in patients who received spinal anesthesia (SA) or general anesthesia (GA) for their ISBT.

MATERIALS AND METHODS

Patients that underwent ISBT from April 2014 to September 2018 were analyzed from a prospective institutional database. The most prevalent malignancies were cervical (45%), recurrent endometrial (27%) and vaginal (20%) cancers. Baseline patient characteristics, radiation treatment details, anesthesia records, and inpatient charts were obtained. Opioid consumption was quantified as oral morphine equivalent per day (OMEq/day) from implantation until removal. Pain score levels were collected by using an 11-point scoring system.

RESULTS

Ninety nine patients received GA and 40 patients received SA as their anesthesia for ISBT. During their first admission, 76 patients (55%) required intravenous opioids. Patients receiving SA had significantly lower mean pain scores on the morning of their procedure 6 (Interquartile range [IQR] 2-8) vs. 0 (IQR: 0-1); p < 0.001]. Pain did not significantly differ between cohorts at any other time. During the first admission, SA patients had a lower median opioid usage of 23 (IQR: 9-47) mg/day compared to GA patients at 38 (IQR: 21-71) mg/day (p = 0.011). No difference in opioid consumption was seen during subsequent admissions.

CONCLUSIONS

In patients undergoing ISBT, SA provides better immediate pain control post insertion compared to GA. Patients who received SA used lower amounts of opioids during their first ISBT insertion.

Quality-of-Life Outcomes and Toxic Effects Among Patients With Cancers of the Uterus Treated With Stereotactic Pelvic Adjuvant Radiation Therapy: The SPARTACUS Phase 1/2 Nonrandomized Controlled Trial

IMPORTANCE

Adjuvant radiation plays an important role in reducing locoregional recurrence in patients with uterine cancer. Although hypofractionated radiotherapy may benefit health care systems and the global community while decreasing treatment burden for patients traveling for daily radiotherapy, it has not been studied prospectively nor in randomized trials for treatment of uterine cancers, and the associated toxic effects and patient quality of life are unknown.

OBJECTIVE

To evaluate acute genitourinary and bowel toxic effects and patient-reported outcomes following stereotactic hypofractionated adjuvant radiation to the pelvis for treatment of uterine cancer.

DESIGN, SETTING, AND PARTICIPANTS

The Stereotactic Pelvic Adjuvant Radiation Therapy in Cancers of the Uterus (SPARTACUS) phase 1/2 nonrandomized controlled trial of patients accrued between May 2019 and August 2021 was conducted as a multicenter trial at 2 cancer centers in Ontario, Canada. In total, 61 patients with uterine cancer stages I through III after surgery entered the study.

INTERVENTIONS

Stereotactic adjuvant pelvic radiation to a dose of 30 Gy in 5 fractions administered every other day or once weekly.

MAIN OUTCOMES AND MEASURES

Assessments of toxic effects and patient-reported quality of life (European Organisation for Research and Treatment of Cancer Quality of Life Questionnaires C30 and endometrial EN24) were collected at baseline, fractions 3 and 5, and at 6 weeks and 3 months of follow-up. Descriptive analysis was conducted, calculating means, SDs, medians, IQRs, and ranges for continuous variables and proportions for categorical variables. Univariate generalized linear mixed models were generated for repeated measurements on the quality-of-life scales.

RESULTS

A total of 61 patients were enrolled (median age, 66 years; range, 51-88 years). Tumor histologic results included 39 endometrioid adenocarcinoma, 15 serous or clear cell, 3 carcinosarcoma, and 4 dedifferentiated. Sixteen patients received sequential chemotherapy, and 9 received additional vault brachytherapy. Median follow-up was 9 months (IQR, 3-15 months). Of 61 patients, worst acute gastrointestinal tract toxic effects of grade 1 were observed in 33 patients (54%) and of grade 2 in 8 patients (13%). For genitourinary worst toxic effects, grade 1 was observed in 25 patients (41%) and grade 2 in 2 patients (3%). One patient (1.6%) had an acute grade 3 gastrointestinal tract toxic effect of diarrhea at fraction 5 that resolved at follow-up. Only patient-reported diarrhea scores were both clinically (scores ≥10) and statistically significantly worse at fraction 5 (mean [SD] score, 35.76 [26.34]) compared with baseline (mean [SD] score, 6.56 [13.36]; P < .001), but this symptom improved at follow-up.

CONCLUSIONS AND RELEVANCE

Results of this phase 1/2 nonrandomized controlled trial suggest that stereotactic hypofractionated radiation was well tolerated at short-term follow-up for treatment of uterine cancer. Longer follow-up and future randomized studies are needed to further evaluate this treatment.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT04866394.

Stereotactic Ablative Radiotherapy for the Management of Liver Metastases from Neuroendocrine Neoplasms: A Preliminary Study

INTRODUCTION

Liver metastases are common in patients with neuroendocrine neoplasms. The role of stereotactic ablative radiotherapy (SABR) is not well understood in this population.

OBJECTIVE

The objective of this study was to evaluate the safety and efficacy of SABR in treating well-differentiated neuroendocrine liver metastases (WD-NELM).

METHODS

A retrospective review of patients with WD-NELM treated with SABR was conducted between January 2015 and July 2019. Demographic, treatment, and clinical/radiographic follow-up data were abstracted. RECIST 1.1 criteria were applied to each individual target to evaluate the response to treatment. Local control (LC) and progression-free survival (PFS) were determined using the Kaplan-Meier methodology. Toxicity was reported according to the CTCAE v5.0.

RESULTS

Twenty-five patients with a total of 53 liver metastases treated with SABR were identified. Most patients (68%) had midgut tumors, were grade 2 (80%), and had high-volume intrahepatic and/or extrahepatic disease (76%). The median number of liver metastases treated was 2, with a median size of 2.5 cm. The median radiation dose delivered was 50 Gy/5 fractions. The median follow-up was 14 months; 24 of the 25 patients were alive at the time of analysis. The objective response rate was 32%, with improvement or stability in 96% of lesions treated. The median time to best response was 9 months. The 1-year LC and PFS were 92 and 44%, respectively. No grade 3/4 acute or late toxicity was identified.

CONCLUSIONS

Liver SABR is a safe and promising means of providing LC for WD-NELM. This treatment modality should be evaluated in selected patients in concert with strategies to manage systemic disease.

Relationship of Urethral Dose and Genitourinary Toxicity Among Patients Receiving Vaginal High Dose Rate Interstitial Brachytherapy

AIMS

Interstitial brachytherapy (ISBT) plays an important role in the management of locally advanced gynaecological malignancies. However, the relationship between urinary toxicity and dose to the urethra is not well understood. We sought to evaluate the correlation between urethral dose and the incidence of genitourinary complications among patients undergoing vaginal high dose rate ISBT.

MATERIALS AND METHODS

Eighty-three patients treated with ISBT between August 2014 and April 2018 were retrospectively reviewed. CTCAE version 5.0 was used to grade toxicity. Individual treatment plans were evaluated to collect dose parameters. Urethral contours were added to the structure sets using a uniform 1 cm diameter brush and minimum doses to the hottest 0.1, 0.2 and 0.5 cm³ (D0.1cm³, D0.2cm³ and D0.5cm³) of the urethra were obtained. Total (ISBT ± external beam radiotherapy) equivalent doses in 2 Gy fractions (EQD2) received by the targets and organs at risk were calculated. Numerical counts (%) and medians (interquartile range) were used to characterise the data. Fisher's exact and the Mann-Whitney-Wilcox tests were used as appropriate. Receiver operator curve analysis was used to define the urethral threshold dose that correlated to genitourinary toxicity.

RESULTS

The median age and follow-up times were 67 years (59-75) and 25 months (16-37), respectively. Patients had predominantly primary endometrial (49%) and vaginal (37%) cancer, with four (5%) patients with metastatic rectal cancer to the vagina. Twenty-four of 79 (30%) patients experienced acute genitourinary toxicity and 34 of 71 (48%) experienced late genitourinary toxicity. In both analyses, the median urethral dose was significantly higher among those with toxicity. Receiver operator curve analysis indicated that D0.1cm³, D0.2cm³ and D0.5cm³ of the urethra were associated with the development of toxicity at doses >78, >71 and >62 Gy, respectively.

CONCLUSION

Urethral dose seems to predict genitourinary toxicity in ISBT of vaginal tumours. Further study with an expanded cohort and longer follow-up is warranted.

Red Blood Cell Transfusion Practices for Patients With Cervical Cancer Undergoing Radiotherapy

IMPORTANCE

Packed red blood cell (PRBC) transfusions are used to treat anemia in patients with cervical cancer undergoing radiotherapy (RT) owing to concerns of hypoxia-induced radioresistance. In the absence of high-quality evidence informing transfusion practices for patients receiving external beam RT (EBRT) and brachytherapy, various arbitrary hemoglobin target levels are used worldwide.

OBJECTIVE

To develop consensus statements to guide PRBC transfusion practices in patients with cervical cancer receiving curative-intent RT with EBRT and brachytherapy.

DESIGN, SETTING, AND PARTICIPANTS

This international Delphi consensus study was completed between November 1, 2019, and July 31, 2020. A total of 63 international clinical experts in gynecologic radiation oncology were invited; 39 (62%) accepted and consented to participate. Consensus building was achieved using a 3-round anonymous Delphi consensus method. Participants rated their agreement or disagreement with statements using a 5-point Likert scale. An a priori threshold of 75% or more was required for consensus.

MAIN OUTCOMES AND MEASURES

The preplanned primary outcome of this study was to assess hemoglobin transfusion thresholds and targets for both EBRT and brachytherapy by expert consensus.

RESULTS

Response rates of 100% (39 of 39), 92% (36 of 39), and 97% (35 of 36) were achieved for the first, second, and third rounds of surveys, respectively. Twenty-three experts (59%) practiced in Canada, 11 (28%) in the United States, 3 (8%) in South America, 1 (3%) in Europe, and 1 (3%) in Asia. Consensus was reached for 44 of 103 statements (43%), which were combined to form the final 27-statement consensus guideline. No specific hemoglobin transfusion threshold was agreed on by consensus for EBRT or brachytherapy. By consensus (89% [31 of 35]), a hemoglobin transfusion target for patients who receive a PRBC transfusion should be 9 g/dL or more and less than 12 g/dL.

CONCLUSIONS AND RELEVANCE

This study presents the first international expert consensus guideline informing PRBC transfusion practices for patients with cervical cancer undergoing EBRT and brachytherapy. A minimum hemoglobin transfusion target of 9 g/dL was endorsed to balance tumor radiosensitivity with appropriate use of a scarce resource. Randomized clinical trials are required to evaluate the optimal transfusion threshold and target that maximize clinical benefit in this patient population.

Review of brachytherapy complications - Upper gastrointestinal tract

While brachytherapy applications are not widely used for cancer diagnoses in the upper GI tract (including the esophagus, liver, stomach, and pancreas), they have a clear role in palliation and symptom management and occasionally definitive locoregional treatment. With the increasing use of image-guided techniques, the incidence of side effects and complications has shown to be lower than many other alternative treatment modalities, making brachytherapy approaches a preferred treatment option. This review examines procedural complications and acute and chronic adverse effects from radiation associated with esophageal, hepatobiliary, and pancreatic brachytherapy and their management.

Comparison of CTVHR and organs at risk contours between TRUS and MR images in IB cervical cancers: a proof of concept study

Purpose

To compare CTV_HR and OAR dimensions and inter-rater agreement between magnetic resonance (MR) and trans-rectal ultrasound (TRUS) images in IB cervical cancer patients.

Methods

IB cervical cancer patients treated with (chemo)radiotherapy plus MR-guided brachytherapy (BT) were prospectively enrolled in this study. Radiation oncologists contoured CTV_HR and OARs in pre-BT MR images (MRI) and intra-operative TRUS images. These contours were subsequently compared in regard to volume and dimension. Contour inter-rater agreement analysis was also investigated using kappa index (KI). Stata 15.0 was used for statistical analysis and a p-value < 0.05 was considered statistically significant.

Results

TRUS CTV_HR volumes were statistically smaller than the respective MRI contoured volumes. TRUS CTV_HR thickness was found to be consistently smaller than MRI contours in all patients. No statistical difference was seen in width and height between the two different imaging modalities. MRI contours had a median KI of 0.66 (range: 0.56–0.77) while TRUS-based contours had a median KI of 0.64 (range: 0.47–0.77). Bladder and rectum had very satisfactory KI in both imaging modalities. Vaginal contours had moderate agreement in MR (0.52) and in TRUS images (0.58).

Conclusion

TRUS images allow good visualization of CTV_HR and OARs in IB cervical cancer patients. Inter-rater contour variability was comparable between TRUS and MR images. TRUS is a promising modality on its own for image-guided BT.

Using infrared depth-sensing technology to improve the brachytherapy operating room experience

PURPOSE

The purpose of this study was to discuss the merits of using depth-sensing infrared camera technology in the brachytherapy operating room during interstitial brachytherapy for gynecologic malignancies.

MATERIALS AND METHODS

The infrared depth-sensing camera from a Microsoft Kinect that had been adapted for surgical use was introduced into a high-volume interstitial brachytherapy operating room. Brachytherapists then used the touchless, gestural interface to review preoperative MRI in real time to guide needle insertion.

RESULTS

The interface was used for 10 consecutive procedures by 4 separate brachytherapists. The initial training and adjustment to the technology was variable among brachytherapists. All brachytherapists found the controls intuitive and were able to successfully navigate MRI on the system after 1, 30, 30, and 45 min. Qualitatively, brachytherapists found the system helpful for interpretation of intraoperative ultrasound imaging. Furthermore, it ensured adequate needle positioning and deposition was maintained for large tumors. Surgeons involved in its use agreed on potential for considerable benefit when performing interstitial brachytherapy.

CONCLUSIONS

Adapting this technology for use in the brachytherapy suite provided a higher level of comfort with interstitial catheter placement. This novel tool or similar technology might be considered within other brachytherapy suites.

Radiotherapy practices in postoperative endometrial cancer: A survey of the ABS membership

PURPOSE

This survey aimed to document the current practice patterns of postoperative radiotherapy (RT), including vaginal vault brachytherapy (VVB) and external beam radiotherapy (EBRT), in the management of patients with endometrial cancer.

METHODS AND MATERIALS

A 30-item, multiple choice survey querying RT prescribing practices and planning techniques was distributed electronically to American Brachytherapy Society members in December 2018.

RESULTS

Seventy-five surveys from 62 centers were completed. Eighty-nine percent of respondents practiced within the USA or Canada. Most (79%) respondents indicated a preference for recommending adjuvant VVB alone in FIGO Stage IB, Grade 2 margin and lymphovascular space invasion (LVSI) negative disease. For FIGO Stage IB, Grade 3, LVSI-positive disease, most respondents preferred incorporating EBRT either alone (33%) or with VVB (28%). For IIIC1, margin positive disease, VVB in addition to EBRT was most commonly recommended (75%). When planning adjuvant EBRT, 49% utilized CT simulation with both bladder full and empty. Internal target volume was utilized by 53%. Volumetric modulated arc therapy (53%) or intensity-modulated radiotherapy (19%) were commonly used planning techniques. The most common dose prescription was 45 Gy in 25 fractions (57%). When treating with VVB, 49% determined applicator size at the time of brachytherapy. Sixty-four percent planned treatments based on CT imaging with the applicator in situ and 33% repeated CT imaging before each subsequent fraction. The most common prescription was 21 Gy in three fractions prescribed to 0.5 cm depth (43%).

CONCLUSIONS

This study identified variability in treatment recommendations and in both EBRT and VVB simulation and planning processes in postoperative endometrial cancer.

Salvage Re-irradiation With Single-modality Interstitial Brachytherapy for the Treatment of Recurrent Gynaecological Tumours in the Pelvis: A Multi-institutional Study

AIMS

Recurrent gynaecological tumours can cause significant morbidity with limited salvage options. This study investigates the strategy of salvage single-modality interstitial brachytherapy (SM-ISBT) for recurrent gynaecological pelvic cancer at two specialised ISBT centres.

MATERIALS AND METHODS

Patients who had received salvage SM-ISBT for pelvic recurrence of gynaecological cancers from September 2008 to January 2017 were included. None had distant metastasis at the time of recurrence. Local control, progression-free and overall survival and long-term toxicities were evaluated.

RESULTS

Twenty-six patients with a median follow-up of 24 months (range 2.5-106.3 months) after SM-ISBT were included. Primary cancer sites were endometrium (20), cervix (4), vulva (1) and vagina (1). All patients had prior whole-pelvic external beam irradiation and 16 had prior brachytherapy. The median disease-free survival prior to SM-ISBT was 20.3 months (interquartile range 9.9-30.5). SM-ISBT was delivered with high dose rate technique over three to six fractions. The median high-risk clinical target volume was 34.6 cm³, with a median D90 of 29.1 Gy (range 16.1-64.6). The median bladder, rectum and sigmoid D2cm³ were 15.5, 18.7 and 3.7 Gy, respectively. After SM-ISBT, complete and partial responses were achieved in 17 (64%) and 5 (19%) patients, respectively. Two (7.4%) patients had grade 3 toxicities (both vaginal stenosis), with no grade 4 complications. Eighteen patients (69%) recurred, including local, regional and metastatic in 14 (54%), 8 (30%) and 5 (19%) patients, respectively. Two-year local control, progression-free survival and overall survival were 50, 38 and 78%, respectively. In follow-up, 12 patients (46%) remained in local control.

CONCLUSIONS

Salvage SM-ISBT re-irradiation for pelvic recurrence of gynaecological malignancies was feasible and safe. With limited salvage options, the local control obtained in more than a quarter of patients seems reasonable. Further efforts are needed to establish a consensus about the optimal patient selection, dose fractionation, implant technique and combination with systemic therapies.

Institutional long-term outcomes at the first Canadian center performing intraoperatively planned low-dose-rate brachytherapy alone in low- and intermediate-risk prostate cancer

PURPOSE

The aim of this study is to report the long-term outcomes and toxicities from a large cohort of patients with localized prostate cancer treated with low-dose-rate intraoperatively planned brachytherapy.

METHODS AND MATERIALS

Prostate-specific antigen levels, urinary symptoms, and erectile function were recorded at baseline, and each followup visit was then entered into a prospective database. Urinary toxicity requiring procedural intervention was retrospectively verified using an integrated electronic medical system. A separate cross-sectional survey was performed to measure postimplant sexual function.

RESULTS

A total of 822 patients with low and favorable intermediate-risk prostate cancer were treated at our institution between 2003 and 2013. The Kaplan-Meier estimates for biochemical recurrence for our cohort were 95% and 87% at 5 and 10 years, respectively. Cystoscopy, transurethral resection of prostate, or dilatation was required for 7.1% of 720 patients with more than 2 years of followup. At a median followup of 3.7 years, 64.4% of patients retained adequate erectile function for intercourse, with 54% of patients who were no longer sexually active postimplant reporting social factors as the primary reason.

CONCLUSIONS

Our institutional experience with intraoperative low-dose-rate prostate brachytherapy yielded excellent long-term results with a low incidence of urinary and sexual toxicity.

An audit of referral and treatment patterns of high-risk prostate cancer patients in Alberta

INTRODUCTION

We aimed to determine the impact of clinical practice guidelines (CPG) on rates of radiation oncologist (RO) referral, androgen-deprivation therapy (ADT), radiation therapy (RT), and radical prostatectomy (RP) in patients with high-risk prostate cancer (HR-PCa).

METHODS

All men >18 years, diagnosed with PCa in 2005 and 2012 were identified from the Alberta Cancer Registry. Patient age, aggregated clinical risk group (ACRG) score, Gleason score (GS), pre-treatment prostate-specific antigen (PSA), RO referral, and treatment received were extracted from electronic medical records. Logistic regression modelling was used to examine associations between RO referral rates and relevant factors.

RESULTS

HR-PCa was diagnosed in 261 of 1792 patients in 2005 and 435 of 2148 in 2012. Median age and ACRG scores were similar in both years (p>0.05). The rate of patients with PSA >20 were 67% and 57% in 2005 and 2012, respectively (p=0.004). GS ≤6 was found in 13% vs. 5% of patients, GS 7 in 27% vs. 24%, and GS ≥8 in 59% vs. 71% in 2005 and 2012, respectively (p<0.001). In 2005, RO referral rate was 68% compared to 56% in 2012 (p=0.001), use of RT + ADT was 53% compared to 32% (p<0.001), and RP rate was 9% vs. 17% (p=0.002). On regression analysis, older age, 2012 year of diagnosis and higher PSA were associated with decreased RO referral rates (odds ratios [OR] 0.49, 95% confidence interval [CI] 0.39-0.61; OR 0.51, 95% CI 0.34-0.76; and OR 0.64, 95% CI 0.39-0.61), respectively [p<0.001]).

CONCLUSIONS

Since CPG creation in 2005, RO referral rates and ADT + RT use declined and RP rates increased, which demonstrates a need to improve adherence to CPG in the HR-PCa population.

Assessing guideline impact on referral patterns of post-prostatectomy patients to radiation oncologists

INTRODUCTION

Adjuvant radiotherapy (aRT) can improve biochemical progression-free survival in patients with high-risk features (HRF) after radical prostatectomy (RP). Guidelines from Alberta and the Genitourinary Radiation Oncologists of Canada (GUROC) recommend that patients with HRF be referred to radiation oncologists (RO) based on the findings from three randomized, controlled trials (RCT). Our study examines the impact of these recommendations both pre- (2005) and post- (2012) publication of RCT and GUROC guideline establishment.

METHODS

Patients undergoing RP during 2005 and 2012 were identified from the provincial cancer registry. Charts were retrospectively reviewed and variables of interest were linked to the registry data. RO referral patterns for each year were determined and variables influencing referral (extracapsular extension, positive margin, seminal vesicle invasion, and post-RP prostate-specific antigen [PSA]) were compared.

RESULTS

Median time to referral was 26.4 months in 2005 compared to 3.7 months 2012 (p<0.001). Among patients referred post-RP, a higher proportion was referred within six months in 2012 (21%) as compared to 2005 (13%) (p=0.003). Among eligible patients in 2012, 30% were referred for discussion of aRT compared to 24% in 2005 (p=0.003). There was a marked drop in patients referred for salvage radiation therapy beyond six months and a rise in the number of patients who are never referred.

CONCLUSIONS

Despite an increase in referral rates to RO post-RP from 2005-2012, more than 50% of those patients with HRF did not receive a referral. Initiatives aimed at improving multidisciplinary care and guideline adherence should be undertaken.