Implementing cone-beam computed tomography-guided online adaptive radiotherapy in cervical cancer.

Background and purpose: Adaptive radiotherapy (ART) in locally advanced cervical cancer (LACC) has shown promising outcomes. This study investigated the feasibility of cone-beam computed tomography (CBCT)-guided online ART (oART) for the treatment of LACC. Material and methods: The quality of the automated radiotherapy treatment plans and artificial intelligence (AI)-driven contour delineation for LACC on a novel CBCT-guided oART system were assessed. Dosimetric analysis of 200 simulated oART sessions were compared with standard treatment. Feasibility of oART was assessed from the delivery of 132 oART fractions for the first five clinical LACC patients. The simulated and live oART sessions compared a fixed planning target volume (PTV) margin of 1.5 cm around the uterus-cervix clinical target volume (CTV) with an internal target volume-based approach. Workflow timing measurements were recorded. Results: The automatically-generated 12-field intensity-modulated radiotherapy plans were comparable to manually generated plans. The AI-driven organ-at-risk (OAR) contouring was acceptable requiring, on average, 12.3 min to edit, with the bowel performing least well and rated as unacceptable in 16 % of cases. The treated patients demonstrated a mean PTV D98% (+/-SD) of 96.7 (+/- 0.2)% for the adapted plans and 94.9 (+/- 3.7)% for the non-adapted scheduled plans (p<10-5). The D2cc (+/-SD) for the bowel, bladder and rectum were reduced by 0.07 (+/- 0.03)Gy, 0.04 (+/-0.05)Gy and 0.04 (+/-0.03)Gy per fraction respectively with the adapted plan (p <10-5). In the live.setting, the mean oART session (+/-SD) from CBCT acquisition to beam-on was 29 +/- 5 (range 21-44) minutes. Conclusion: CBCT-guided oART was shown to be feasible with dosimetric benefits for patients with LACC. Further work to analyse potential reductions in PTV margins is ongoing.

Pain and symptom relief using inhaled methoxyflurane for gynecologic brachytherapy applicator removal.

Purpose: Intra-cavitary brachytherapy forms an essential part of the curative treatment of cervical and vaginal cancer, and can be used for cure or palliation in endometrial and vulval cancers. Removal of brachytherapy applicators is often performed after anaesthesia has worn off and can be an uncomfortable and anxiety-provoking procedure. In this paper, we present our experience in a series of patients before and after the introduction of inhaled methoxyflurane (IMF, Penthrox™). Material and methods: Questionnaires were sent to patients prior to the introduction of IMF to retrospectively score pain and anxiety during the brachytherapy procedure. Following successful review by the local drugs and therapeutic committee as well as staff training, IMF was introduced and offered to patients during applicator removal. Prospective pain scores and retrospective questionnaires were collected. Pain was rated on a scale of 0 to 10, with zero being no pain and 10 being extreme pain. Results: Thirteen patients returned retrospective questionnaires prior to IMF introduction and seven patients following IMF introduction. After the first brachytherapy insertion, the mean recollected pain score during applicator removal decreased from 6/10 to 1/10 (p = 0.002). The mean recollected pain score one hour after applicator removal reduced from 3/10 to 0 (p = 0.04). Prospective measurements for 77 insertions in 44 patients receiving IMF reported a median pain score of 1/10 immediately before applicator removal (range, 0-10), and 0/10 immediately after applicator removal (range, 0-5). Conclusions: Inhaled methoxyflurane is easily administered and effective method of decreasing pain during applicator removal following gynecologic brachytherapy.

Planned organ preservation for elderly patients with rectal cancer using short course radiotherapy and a contact brachytherapy boost-an International multi-institution analysis.

Background and purpose: The use of external beam radiotherapy (EBRT) and contact X-Ray brachytherapy (CXB) is emerging as an effective alternative in patients with early stage rectal cancer with the intent of organ preservation (OP). Short course radiotherapy (SCRT) is an alternative EBRT schedule for patients not fit for chemotherapy or for longer courses of EBRT. There are no multicentre studies that have reported on the outcomes of SCRT with a CXB boost, therefore we present these from patients from centres from the UK and Sweden. Materials and methods: From the Guildford Colorectal Database or local databases, 258 patients who underwent SCRT and CXB with the intent of OP from five centres treated between 2007 and 2019 were identified. Response and survival data was analysed and presented. Results: With a median age of 81, 226 patients were treated with radiotherapy alone (RTA) and 32 immediately after local excision (ILE). Median follow-up was 24 months. 70% and 97% of patients in the RTA and ILE groups respectively had a complete clinical response (cCR) after SCRT with CXB. Of those, local relapse was seen in 16% of the RTA and 3% of the ILE group. Median survival was 40 months after CXB in the RTA and 52 months in the ILE group. 94% of patients remained stoma-free to the point of latest follow-up. Conclusion: This data suggests that CXB when combined with SCRT, in a mainly elderly and comorbid population, provides good palliation with stoma-avoidance. Oncological outcomes compare with previously published work. A greater focus is required on quality of life outcomes after OP.

Endorectal contact radiation boosting: Making the case for dose AND volume reporting.

INTRODUCTION: The various rectal endoluminal radiation techniques all have steep, but different, dose gradients. In rectal contact brachytherapy (CXB) doses are typically prescribed and reported to the applicator surface and not to the gross tumor volume (GTV), clinical target volume (CTV) or organs at risk (OAR), which is crucial to understand tumor response and toxicity rates. To quantify the above-described problem, we performed a dose modeling study using a fixed prescription dose at the surface of the applicator and varied tumor response scenarios. METHODS: Endorectal ultrasound-based 3D-volume-models of rectal tumors and the rectal wall were used to simulate the delivered dose to GTV, CTV and the rectal wall layers, assuming treatment with Maastro HDR contact applicator for rectal cancer with a fixed prescription dose to the applicator surface (equivalent to 3 × 30 Gy CXB) and various response scenarios. RESULTS: An identical prescribed dose to the surface of the applicator resulted in a broad range of doses delivered to the GTV, CTV and the uninvolved intestinal wall. For example, the equieffective dose in 2 Gy per fraction (EQD2) D90% of the GTV varied between 63 and 231 Gy, whereas the EQD2 D2cc of the rectal wall varied between 97 and 165 Gy. CONCLUSION: Doses prescribed at the surface are not representative of the dose received by the tumor and the bowel wall. This stresses the relevance of dose reporting and prescription to GTV and CTV volumes and OAR in order to gain insight between delivered dose, local control and toxicity and to optimize treatment protocols.

GEC ESTRO ACROP consensus recommendations for contact brachytherapy for rectal cancer.

PURPOSE: To issue consensus recommendations for contact X-Ray brachytherapy (CXB) for rectal cancer covering pre-treatment evaluation, treatment, dosimetric issues and follow-up. These recommendations cover CXB in the definitive and palliative setting. METHODS: Members of GEC ESTRO with expertise in rectal CXB issued consensus-based recommendations for CXB based on literature review and clinical experience. Levels of evidence according to the Oxford Centre for Evidence based medicine guidance are presented where possible. RESULTS: The GEC ESTRO ACROP consensus recommendations support the use of CXB to increase the chances of clinical complete remission and cure for patients who are elderly with high surgical risk, surgically unfit or refusing surgery. For palliative treatment, the use of CXB is recommended for symptomatic relief and disease control. The use of CXB in an organ-preservation setting in surgically fit patients is recommended within the setting of a clinical trial or registry. CONCLUSIONS: The GEC ESTRO ACROP recommendations for CXB are provided. Recommendations towards standardisation of reporting and prescription are given. Practitioners are encouraged to follow these recommendations and to develop further clinical trials to examine this treatment modality and increase the evidence base for its use. The routine collection of outcomes both clinical and patient-reported is also encouraged.

Modern Brachytherapy.

Brachytherapy involves the placement of radioactive sources within or very close to the tumor. This placement allows a high dose of radiotherapy to be delivered to the tumor while sparing the surrounding normal tissue. The delivery of brachytherapy has changed markedly over the years, with newer radioactive sources making delivery safer, image guidance techniques allowing more accurate placement of sources, and advanced planning systems allowing brachytherapy to be truly adaptive. This article explores the most modern techniques and current uses of brachytherapy in the treatment of gynecological, prostate, breast, rectal, and skin cancers.

Radiological and clinical findings following rectal contact X-ray brachytherapy (Papillon technique) - how to assess response.

PURPOSE: Rectal contact X-ray brachytherapy (Papillon radiotherapy) has recently received approval from the National Institute for Health and Care Excellence. In particular, it is suitable for elderly patients who are high-risk for a major operation, but it may also be undertaken for patients who wish to avoid a stoma. It is imperative to be able to identify clinical response or tumor regrowth on surveillance magnetic resonance imaging (MRI) and sigmoidoscopy. This article aims to help clinicians to interpret MRIs and endoscopic appearances following Papillon radiotherapy. MATERIAL AND METHODS: MRI and sigmoidoscopy images are presented from a case series of seven non-consecutive, heterogeneously treated patients with T2 to 3C N0 rectal adenocarcinoma. Treatments included transanal excision, adjuvant or neoadjuvant chemo/radiotherapy, and Papillon radiotherapy. These patients wished to avoid a stoma or were high-risk for a major operation. These cases have been chosen to demonstrate response assessment alone. RESULTS: The "black spider" sign of maturing, low signal fibrosis on MRI was found to be reassuring, as was the presence of a flat scar on endoscopy. Residual tumor mass or intermediate signal suggest equivocal response, which may necessitate transanal excision. Loss of low signal fibrosis, or the development of soft tissue nodularity or mass should prompt biopsy. CONCLUSIONS: MR scans should be used in combination with endoluminal mucosal assessment (and digital rectal examination) to determine response following Papillon radiotherapy. This is the first paper to describe both the endoscopic and imaging findings following Papillon radiotherapy.

Swallowing outcomes in children after slide tracheoplasty.

INTRODUCTION: Slide tracheoplasty is now considered gold standard treatment for long segment congenital tracheal stenosis. Outcomes are typically focused upon airway patency. Dysphagia is often reported in children undergoing cardiothoracic surgery, but not specifically after slide tracheoplasty. This study was carried out to describe the nature and prevalence of dysphagia following slide tracheoplasty for long segment congenital tracheal stenosis. METHODS: Retrospective case note review was conducted on a series of patients who underwent swallow evaluation following slide tracheoplasty between 2006 and 2014. A clinical swallow assessment was carried out by a Speech and Language Therapist with videofluoroscopic evaluation of swallowing where indicated. Logistic regression assessed the impact of gender, feeding history, weight, tracheal diameter, stenting and co-morbidities on the likelihood of having post-operative dysphagia. RESULTS: 43 out of 83 slide tracheoplasty patients underwent swallow evaluation. Dysphagia was identified in 30 (70%) of 43 patients. Videofluoroscopy was undertaken in 22 of these patients. All patients who had a videofluoroscopy presented with altered swallow physiology. Aspiration risk was confirmed in 15 patients with frank aspiration seen in 9. Pre-operative history of dysphagia was present in 9 patients. There were two cases of vocal fold palsy. The presence of a stent was the strongest predictor of post-operative dysphagia with an odds ratio of 10.6 (95% CI 1.2-92.8). CONCLUSIONS: This study documents a high prevalence of post-operative dysphagia in a pediatric population following slide tracheoplasty. In most cases there was no history suggestive of dysphagia pre-operatively. Swallowing needs to be assessed after slide tracheoplasty and longitudinal studies are required.

Clinical validation and benchmarking of knowledge-based IMRT and VMAT treatment planning in pelvic anatomy.

PURPOSE: The aim of this work was to determine whether a commercial knowledge-based treatment planning (KBP) module can efficiently produce IMRT and VMAT plans in the pelvic region (prostate & cervical cancer), and to assess sensitivity of plan quality to training data and model parameters. METHODS: Initial benchmarking of KBP was performed using prostate cancer cases. Structures and dose distributions from 40 patients previously treated using a 5-field IMRT technique were used for model training. Two types of model were created: one excluded statistical outliers (as identified by RapidPlan guidelines) and the other had no exclusions. A separate model for cervix uteri cancer cases was subsequently developed using 37 clinical patients treated for cervical cancer using RapidArc™ VMAT, with no exclusions. The resulting models were then used to generate plans for ten patients from each patient group who had not been included in the modelling process. Comparisons of generated RapidPlans with the corresponding clinical plans were carried out to indicate the required modifications to the models. Model parameters were then iteratively adjusted until plan quality converged with that obtained by experienced planners without KBP. RESULTS: Initial automated model generation settings led to poor conformity, coverage and efficiency compared to clinical plans. Therefore a number of changes to the initial KBP models were required. Before model optimisation, it was found that the PTV coverage was slightly reduced in the superior and inferior directions for RapidPlan compared with clinical plans and therefore PTV parameters were adjusted to improve coverage. OAR doses were similar for both RapidPlan and clinical plans (p>0.05). Excluding outliers had little effect on plan quality (p≫0.05). Manually fixing key optimisation objectives enabled production of clinically acceptable treatment plans without further planner intervention for 9 of 10 prostate test patients and all 10 cervix test patients. CONCLUSIONS: The Varian RapidPlan™ system was able to produce IMRT & VMAT treatment plans in the pelvis, in a single optimisation, that had comparable sparing and comparable or better conformity than the original clinically acceptable plans. The system allows for better consistency and efficiency in the treatment planning process and has therefore been adopted clinically within our institute with over 100 patients treated.

Equivalent uniform dose for accelerated partial breast irradiation using the MammoSite applicator.

INTRODUCTION: This study aims to quantify the radiobiology of the MammoSite applicator and examine whether there is a relationship between equivalent uniform dose (EUD) and radiotherapy-associated toxicity. METHODS AND MATERIALS: A previously-published version of the linear quadratic (LQ) model, designed to address the impact of dose-gradients in brachytherapy applications, was used to determine the biological effective dose (BED), equivalent dose in 2 Gray per fraction (EQD2) and EUD for the most common fractionation scheme for the MammoSite catheter (34 Gy in 10 fractions prescribed to 1cm from the balloon surface), using a range of balloon sizes in a series of patients treated with single or multiple dwell positions. Toxicity from the MammoSite catheter was assessed and statistical associations with the calculated EUDs were investigated. RESULTS: The acute- and late-toxicity EUDs respectively range from 34.8-39.4 Gy and 33.4-37.6 Gy, with EUD decreasing as balloon diameter increases and/or the number of dwell positions increases. There was a positive association between EUD and hyperpigmentation and telangiectasia. CONCLUSIONS: For APBI using the Mammosite applicator, EUD is higher than the marginal prescription dose and, for the dose-fractionation patterns considered here, was associated with acute and late skin toxicity. EUD is a potentially useful parameter to characterize non-uniform dose distributions related to brachytherapy treatments. Further evaluation in future studies is warranted.

Comparison of conventional radiotherapy and intensity-modulated radiotherapy for post-operative radiotherapy for primary extremity soft tissue sarcoma.

INTRODUCTION: Doses in conventional radiotherapy for extremity soft tissue sarcoma (STS) potentially exceed normal tissue tolerances. This study compares 3D-conformal radiotherapy (3D-CRT) with intensity-modulated radiotherapy (IMRT) in optimising target volume coverage and minimising integral dose to organs-at-risk (OAR). METHODS AND MATERIALS: Ten patients undergoing post-operative radiotherapy for extremity STS were assessed. PTV(1) was defined as tumour bed plus 5cm superiorly/inferiorly and 3cm circumferentially, PTV(2) was defined as 2cm isotropically. OAR were defined as whole femur, neurovascular bundle, tissue corridor and normal tissue outside PTV(1). For each patient 2-phase 3D-CRT was compared to 2/3 field (2/3f) and 4/5 field (4/5f) IMRT with simultaneous integrated boost (SIB). The primary planning objective was to minimise femur and skin corridor dose. Volumetric analysis and conformity and heterogeneity indices were used for plan comparison. RESULTS: A planning protocol containing dose/volume constraints for target and OAR was defined. 4/5f IMRT showed greatest conformity and homogeneity. IMRT resulted in significantly lower femur V45 using 2/3f (p=0.01) and 4/5f (p=0.0009) than 3D-CRT. 4/5f IMRT resulted in significantly lower normal tissue V55 (p=0.004) and maximum dose (p=0.04) than 3D-CRT. CONCLUSIONS: A reproducible set of planning guidelines and dose-volume constraints for 3D-CRT and IMRT planning for extremity sarcomas was devised. 4/5f IMRT with SIB resulted in better target coverage and significantly decreased OAR dose. Further evaluation of this technique within a clinical trial is recommended to demonstrate that the technical benefit of the more complex technique translates into patient-derived benefit by reducing late toxicity.

Intraoperative seed placement for thoracic malignancy-A review of technique, indications, and published literature.

PURPOSE: This review examines the role of permanent radioactive seed implantation in thoracic malignancy. This technique can be used intraoperatively to provide additional highly localized radiation therapy in cases where optimal oncologic margins are unattainable or to palliate unresectable disease. METHODS AND MATERIALS: Relevant trials were identified through a systematic literature search using Pubmed. RESULTS: The intraoperative placement of brachytherapy seeds has been described after sublobar resection for non-small-cell lung cancer (NSCLC), where surgical margins are close or microscopically positive and in the presence of macroscopic residual disease. This brachytherapy technique is currently the focus of a randomized prospective trial in the USA in patients unfit for lobectomy for early-stage NSCLC. CONCLUSIONS: This review summarizes the methods of brachytherapy seed placement and the published experience of brachytherapy implants within the thorax, also examining radiation safety and postoperative dosimetry. This technique has the potential to improve local control with optimal sparing of normal tissue owing to its highly conformal radiotherapy delivery.

Dose volume histogram analysis of normal structures associated with accelerated partial breast irradiation delivered by high dose rate brachytherapy and comparison with whole breast external beam radiotherapy fields.

PURPOSE: To assess the radiation dose delivered to the heart and ipsilateral lung during accelerated partial breast brachytherapy using a MammoSite applicator and compare to those produced by whole breast external beam radiotherapy (WBRT). MATERIALS AND METHODS: Dosimetric analysis was conducted on patients receiving MammoSite breast brachytherapy following conservative surgery for invasive ductal carcinoma. Cardiac dose was evaluated for patients with left breast tumors with a CT scan encompassing the entire heart. Lung dose was evaluated for patients in whom the entire lung was scanned. The prescription dose of 3400 cGy was 1 cm from the balloon surface. MammoSite dosimetry was compared to simulated WBRT fields with and without radiobiological correction for the effects of dose and fractionation. Dose parameters such as the volume of the structure receiving 10 Gy or more (V10) and the dose received by 20 cc of the structure (D20), were calculated as well as the maximum and mean doses received. RESULTS: Fifteen patients were studied, five had complete lung data and six had left-sided tumors with complete cardiac data. Ipsilateral lung volumes ranged from 925-1380 cc. Cardiac volumes ranged from 337-551 cc. MammoSite resulted in a significantly lower percentage lung V30 and lung and cardiac V20 than the WBRT fields, with and without radiobiological correction. CONCLUSION: This study gives low values for incidental radiation received by the heart and ipsilateral lung using the MammoSite applicator. The volume of heart and lung irradiated to clinically significant levels was significantly lower with the MammoSite applicator than using simulated WBRT fields of the same CT data sets.

Prospective clinical trial of bladder filling and three-dimensional dosimetry in high-dose-rate vaginal cuff brachytherapy.

PURPOSE: To investigate the effect of bladder filling on dosimetry and to determine the best bladder dosimetric parameter for vaginal cuff brachytherapy. METHODS AND MATERIALS: In this prospective clinical trial, a total of 20 women underwent vaginal cylinder high-dose-rate brachytherapy. The bladder was full for Fraction 2 and empty for Fraction 3. Dose-volume histogram and dose-surface histogram values were generated for the bladder, rectum, and urethra. The midline maximal bladder point (MBP) and the midline maximal rectal point were recorded. Paired t tests, Pearson correlations, and regression analyses were performed. RESULTS: The volume and surface area of the irradiated bladder were significantly smaller when the bladder was empty than when full. Of the several dose-volume histogram and dose-surface histogram parameters evaluated, the bladder maximal dose received by 2 cm(3) of tissue, volume of bladder receiving >/=50% of the dose, volume of bladder receiving >/=70% of the dose, and surface area of bladder receiving >/=50% of the dose significantly predicted for the difference between the empty vs. full filling state. The volume of bladder receiving >/=70% of the dose and the maximal dose received by 2 cm(3) of tissue correlated significantly with the MBP. Bladder filling did not alter the volume or surface area of the rectum irradiated. However, an empty bladder did result in the nearest point of bowel being significantly closer to the vaginal cylinder than when the bladder was full. CONCLUSIONS: Patients undergoing vaginal cuff brachytherapy treated with an empty bladder have a lower bladder dose than those treated with a full bladder. The MBP correlated well with the volumetric assessments of bladder dose and provided a noninvasive method for reporting the MBP dose using three-dimensional imaging. The MBP can therefore be used as a surrogate for complex dosimetry in the clinic.

Inherent change in MammoSite applicator three-dimensional geometry over time.

Accelerated partial breast irradiation is commonly done with the MammoSite applicator, which requires symmetry to treat the patient. This paper describes three cases that were asymmetric when initially placed and became symmetric over time, without manipulation.

Severe toxicity after permanent radioactive seed implantation for mediastinal carcinoid tumors.

PURPOSE: Permanent implantation of 125I seeds may be used when uninvolved surgical margins are unobtainable or close. Two cases of mediastinal carcinoid tumors with prior chemoradiation had tumors adherent to esophageal muscularis. Both underwent intraoperative permanent seed implantation and developed esophageal fistulas requiring surgical correction. METHODS AND MATERIALS: Custom permanent 125I seed mesh implants were fashioned intraoperatively in a geometrically coherent pattern. The implants were directly sutured to the partially resected esophageal wall. The postimplant CT scans were fused with the postfistula scans to provide dosimetric information at the fistula site. Doses were calculated from time of insertion to time of fistula formation. Neither patient showed evidence of disease recurrence at the time of fistula repair. RESULTS: Patient 1 developed an esophageal-pleural fistula 83 days after seed implantation. Patient 2 developed a broncho-pleural fistula 300 days after seed implantation. CONCLUSIONS: These cases demonstrated that implantation in the setting of extensive subcarinal space dissection and partial esophageal wall resection could cause fistula formation and the need for additional surgery. The high mucosal dose, despite the relatively low activity implant, was due to lack of geometric sparing of the mucosa. We recommend that extensive subcarinal space dissection be considered a contraindication to permanent seed implantation.

Deformable structure registration of bladder through surface mapping.

Cumulative dose distributions in fractionated radiation therapy depict the dose to normal tissues and therefore may permit an estimation of the risk of normal tissue complications. However, calculation of these distributions is highly challenging because of interfractional changes in the geometry of patient anatomy. This work presents an algorithm for deformable structure registration of the bladder and the verification of the accuracy of the algorithm using phantom and patient data. In this algorithm, the registration process involves conformal mapping of genus zero surfaces using finite element analysis, and guided by three control landmarks. The registration produces a correspondence between fractions of the triangular meshes used to describe the bladder surface. For validation of the algorithm, two types of balloons were inflated gradually to three times their original size, and several computerized tomography (CT) scans were taken during the process. The registration algorithm yielded a local accuracy of 4 mm along the balloon surface. The algorithm was then applied to CT data of patients receiving fractionated high-dose-rate brachytherapy to the vaginal cuff, with the vaginal cylinder in situ. The patients' bladder filling status was intentionally different for each fraction. The three required control landmark points were identified for the bladder based on anatomy. Out of an Institutional Review Board (IRB) approved study of 20 patients, 3 had radiographically identifiable points near the bladder surface that were used for verification of the accuracy of the registration. The verification point as seen in each fraction was compared with its predicted location based on affine as well as deformable registration. Despite the variation in bladder shape and volume, the deformable registration was accurate to 5 mm, consistently outperforming the affine registration. We conclude that the structure registration algorithm presented works with reasonable accuracy and provides a means of calculating cumulative dose distributions.

Current controversies in high-dose-rate versus low-dose-rate brachytherapy for cervical cancer.

The use of brachytherapy in the treatment of cervical cancer has increased worldwide since its initial introduction over 100 years ago. However, certain aspects of the use of high-dose-rate (HDR) versus low-dose-rate (LDR) brachytherapy continue to be controversial, particularly the role of HDR in FIGO Stage III cervical cancer and the use of HDR with concurrent chemotherapy. This study represents a systematic literature review of prospective and retrospective series of patients with cervical carcinoma treated with external-beam radiation (EBRT) followed by either HDR or LDR radiation. The local control rates, survival rates, and treatment-related complications in patients with Stage III cervical cancer treated with HDR or LDR and those treated with concomitant chemotherapy are examined. Patients with Stage III cervical cancer treated with EBRT and brachytherapy have a local control rate of >50% in most series. Randomized prospective and retrospective studies show overall statistically equivalent local control, overall survival, and complication rates between HDR and LDR. However, LDR may be preferable for large, bulky tumors at the time of brachytherapy. Retrospective studies of HDR and concurrent chemotherapy are limited but have demonstrated toxicity rates similar to those with LDR. Selected patients with Stage III cervical carcinoma who have an adequate response to EBRT and concomitant chemotherapy may be treated with HDR brachytherapy. The existing literature shows no significant increase in complications in patients treated with HDR and concurrent chemotherapy; however, sufficient tumor shrinkage prior to HDR and careful monitoring of the dose to the normal tissues are imperative.