Clinical outcome of protocol based image (MRI) guided adaptive brachytherapy combined with 3D conformal radiotherapy with or without chemotherapy in patients with locally advanced cervical cancer

Brachytherapy in cancer cervix: Time to move ahead from point A?

Brachytherapy forms an integral part of the radiation therapy in cancer cervix. The dose prescription for intracavitary brachytherapy (ICBT) in cancer cervix is based on Tod and Meredith's point A and has been in practice since 1938. This was proposed at a time when accessibility to imaging technology and dose computation facilities was limited. The concept has been in practice worldwide for more than half a century and has been the fulcrum of all ICBT treatments, strategies and outcome measures. The method is simple and can be adapted by all centres practicing ICBT in cancer cervix. However, with the widespread availability of imaging techniques, clinical use of different dose-rates, availability of a host of applicators fabricated with image compatible materials, radiobiological implications of dose equivalence and its impact on tumour and organs at risk; more and more weight is being laid down on individualised image based brachytherapy. Thus, computed tomography, magnetic-resonance imaging and even positron emission computerized tomography along with brachytherapy treatment planning system are being increasingly adopted with promising outcomes. The present article reviews the evolution of dose prescription concepts in ICBT in cancer cervix and brings forward the need for image based brachytherapy to evaluate clinical outcomes. As is evident, a gradual transition from "point" based brachytherapy to "profile" based image guided brachytherapy is gaining widespread acceptance for dose prescription, reporting and outcome evaluation in the clinical practice of ICBT in cancer cervix.

Cervical gross tumor volume dose predicts local control using magnetic resonance imaging/diffusion-weighted imaging-guided high-dose-rate and positron emission tomography/computed tomography-guided intensity modulated radiation therapy

PURPOSE

Magnetic resonance imaging/diffusion weighted-imaging (MRI/DWI)-guided high-dose-rate (HDR) brachytherapy and (18)F-fluorodeoxyglucose (FDG) - positron emission tomography/computed tomography (PET/CT)-guided intensity modulated radiation therapy (IMRT) for the definitive treatment of cervical cancer is a novel treatment technique. The purpose of this study was to report our analysis of dose-volume parameters predicting gross tumor volume (GTV) control.

METHODS AND MATERIALS

We analyzed the records of 134 patients with International Federation of Gynecology and Obstetrics stages IB1-IVB cervical cancer treated with combined MRI-guided HDR and IMRT from July 2009 to July 2011. IMRT was targeted to the metabolic tumor volume and lymph nodes by use of FDG-PET/CT simulation. The GTV for each HDR fraction was delineated by use of T2-weighted or apparent diffusion coefficient maps from diffusion-weighted sequences. The D100, D90, and Dmean delivered to the GTV from HDR and IMRT were summed to EQD2.

RESULTS

One hundred twenty-five patients received all irradiation treatment as planned, and 9 did not complete treatment. All 134 patients are included in this analysis. Treatment failure in the cervix occurred in 24 patients (18.0%). Patients with cervix failures had a lower D100, D90, and Dmean than those who did not experience failure in the cervix. The respective doses to the GTV were 41, 58, and 136 Gy for failures compared with 67, 99, and 236 Gy for those who did not experience failure (P<.001). Probit analysis estimated the minimum D100, D90, and Dmean doses required for ≥90% local control to be 69, 98, and 260 Gy (P<.001).

CONCLUSIONS

Total dose delivered to the GTV from combined MRI-guided HDR and PET/CT-guided IMRT is highly correlated with local tumor control. The findings can be directly applied in the clinic for dose adaptation to maximize local control.

The role of elective para-aortic lymph node irradiation in patients with locally advanced cervical cancer

AIMS

Pelvic lymph node positivity in cervical cancer is known to be an adverse prognostic factor and is associated with an elevated risk of clinically occult para-aortic lymph node metastases. The purpose of this study was to examine the benefit of elective para-aortic lymph node radiotherapy (PART) in patients with no clinical or radiographic evidence of para-aortic lymph node metastases receiving concurrent cisplatin chemotherapy.

MATERIALS AND METHODS

Patients treated with radiotherapy and concurrent cisplatin for cervical cancer from 1999 to 2009 were identified in two prospective databases. All patients received external beam pelvic radiotherapy (PRT) to a median dose of 50 Gy concurrently with weekly cisplatin 40 mg/m(2). This was followed by pulse dose rate intracavitary brachytherapy to a median dose of 40 Gy. Patients at high risk of occult para-aortic metastases also received PART to a median dose of 40 Gy.

RESULTS

There were 228 patients suitable for analysis; the median follow-up was 4.6 years. The addition of PART to PRT was not associated with a significant difference in disease-free survival (hazard ratio 1.1, confidence interval 0.7-1.8, P = 0.75) or overall survival (hazard ratio 1.6, confidence interval 0.9-2.7, P = 0.11) on multivariate analysis. There was no significant difference in the rate of para-aortic relapse with PART versus PRT (hazard ratio 2.01, confidence interval 0.79-5.12, P = 0.14). The 3 year grade 3-4 late toxicities were 11% for the PART group versus 8% for PRT (hazard ratio 1.39, confidence interval 0.58-3.37, P = 0.47).

CONCLUSIONS

These results suggest that cervical cancer patients treated with radiotherapy and concurrent cisplatin do not benefit from elective PART.

Cervix cancer brachytherapy: high dose rate

Cervical cancer, although less common in industrialized countries, is the fourth most common cancer affecting women worldwide and the fourth leading cause of cancer death. In developing countries, these cancers are often discovered at a later stage in the form of locally advanced tumour with a poor prognosis. Depending on the stage of the disease, treatment is mainly based on a chemoradiotherapy followed by uterovaginal brachytherapy ending by a potential remaining tumour surgery or in principle for some teams. The role of irradiation is crucial to ensure a better local control. It has been shown that the more the delivered dose is important, the better the local results are. In order to preserve the maximum of organs at risk and to allow this dose escalation, brachytherapy (intracavitary and/or interstitial) has been progressively introduced. Its evolution and its progressive improvement have led to the development of high dose rate brachytherapy, the advantages of which are especially based on the possibility of outpatient treatment while maintaining the effectiveness of other brachytherapy forms (i.e., low dose rate or pulsed dose rate). Numerous innovations have also been completed in the field of imaging, leading to a progress in treatment planning systems by switching from two-dimensional form to a three-dimensional one. Image-guided brachytherapy allows more precise target volume delineation as well as an optimized dosimetry permitting a better coverage of target volumes.

Dynamic rotating-shield brachytherapy

PURPOSE

To present dynamic rotating shield brachytherapy (D-RSBT), a novel form of high-dose-rate brachytherapy (HDR-BT) with electronic brachytherapy source, where the radiation shield is capable of changing emission angles during the radiation delivery process.

METHODS

A D-RSBT system uses two layers of independently rotating tungsten alloy shields, each with a 180° azimuthal emission angle. The D-RSBT planning is separated into two stages: anchor plan optimization and optimal sequencing. In the anchor plan optimization, anchor plans are generated by maximizing the D90 for the high-risk clinical-tumor-volume (HR-CTV) assuming a fixed azimuthal emission angle of 11.25°. In the optimal sequencing, treatment plans that most closely approximate the anchor plans under the delivery-time constraint will be efficiently computed. Treatment plans for five cervical cancer patients were generated for D-RSBT, single-shield RSBT (S-RSBT), and (192)Ir-based intracavitary brachytherapy with supplementary interstitial brachytherapy (IS + ICBT) assuming five treatment fractions. External beam radiotherapy doses of 45 Gy in 25 fractions of 1.8 Gy each were accounted for. The high-risk clinical target volume (HR-CTV) doses were escalated such that the D2cc of the rectum, sigmoid colon, or bladder reached its tolerance equivalent dose in 2 Gy fractions (EQD2 with α∕β = 3 Gy) of 75 Gy, 75 Gy, or 90 Gy, respectively.

RESULTS

For the patients considered, IS + ICBT had an average total dwell time of 5.7 minutes∕fraction (min∕fx) assuming a 10 Ci(192)Ir source, and the average HR-CTV D90 was 78.9 Gy. In order to match the HR-CTV D90 of IS + ICBT, D-RSBT required an average of 10.1 min∕fx more delivery time, and S-RSBT required 6.7 min∕fx more. If an additional 20 min∕fx of delivery time is allowed beyond that of the IS + ICBT case, D-RSBT and S-RSBT increased the HR-CTV D90 above IS + ICBT by an average of 16.3 Gy and 9.1 Gy, respectively.

CONCLUSIONS

For cervical cancer patients, D-RSBT can boost HR-CTV D90 over IS + ICBT and S-RSBT without violating the tolerance doses to the bladder, rectum, or sigmoid. The D90 improvements from D-RSBT depend on the patient, the delivery time budget, and the applicator structure.

Practically achievable maximum high-risk clinical target volume doses in MRI-guided intracavitary brachytherapy for cervical cancer: a planning study

PURPOSE

To explore maximum high-risk clinical target volume (HR-CTV) doses that can be practically achieved when organs at risk (OARs; bladder, rectum, and sigmoid) doses are allowed to equal current recommended thresholds in MRI-based intracavitary brachytherapy (BT) planning for cervical cancer.

METHODS AND MATERIALS

Planning MRI sets were retrieved for 21 patients who received pulsed-dose-rate BT boost. Plans were generated using manual optimization (MO) by adjusting dwell positions and times to obtain the prescribed HR-CTV isodose that includes 90% of target (D90) coverage of 35 Gy while limiting OAR doses to below recommended tolerances (prescribed dose target [TGT] plans). Additional planning was performed with automatic volume optimization (VO) to evaluate target coverage relative to the MO plans. The MO and VO approaches were then applied with the objective of obtaining the highest possible HR-CTV coverage when OAR doses were allowed to equal threshold tolerance values (maximized [MAX] plans). A two-tailed paired t test was performed to determine the statistical significance of the results; significance level set at p < 0.013.

RESULTS

MO and VO planning techniques could conform HR-CTV D90 to the prescribed dose quite similarly for TGT plans. Using the MAX approach, the HR-CTV D90 could be increased by 30% and 37% for MO and VO, respectively, without exceeding OAR thresholds. Sigmoid and often rectum were the dose-limiting structures during MAX planning.

CONCLUSIONS

Simple differences in the approach to volumetric MRI-based cervix BT treatment planning can impact HR-CTV D90. Consequently, dose escalation for MRI-guided cervix BT appears feasible in this manner should clinical circumstances warrant.

Reirradiation using high-dose-rate brachytherapy in recurrent carcinoma of uterine cervix

PURPOSE

To assess the feasibility of reirradiation with image-based high-dose-rate brachytherapy in previously irradiated patients with recurrent carcinoma of uterine cervix.

METHODS AND MATERIALS

Thirty previously irradiated patients diagnosed with central recurrence were treated with reirradiation. Martinez Universal Perineal Implant Template was used in 24 patients and Vienna applicator in 6 patients. Median interval between two radiation schedules was 25 months. Median delivered dose was 42 Gy equivalent dose at 2 Gy (EQD2; interquartile range, 37-46 Gy EQD2).

RESULTS

All 30 patients tolerated reirradiation well. Complete response was seen in 23 (76%) patients. With a median followup of 25 months, 2-year local control, disease-free survival, and overall survival were 44%, 42%, and 52%, respectively. Fifteen patients developed local recurrences; Local control rate was significantly higher with doses >40 Gy EQD2 (52% vs. 34%; p = 0.05). Disease-free survival was better for patients with longer interval (>25 months) between two radiotherapy schedules. Grade III radiation proctitis and cystitis was seen in 3 patients each, and Grade II small bowel toxicity was seen in 3 patients.

CONCLUSIONS

Reirradiation using high-dose-rate brachytherapy is feasible with acceptable outcomes in isolated local recurrence deemed unsuitable for surgery. The outcome is better with higher doses.

Assessment of uterus position as a surrogate for high-risk clinical target volume with respect to the applicator position for multiple fractions of brachytherapy in cervical cancer

AIM

Hybrid magnetic resonance imaging/computerized tomography (MRI/CT) planning for high-dose-rate (HDR) brachytherapy in cervical cancer with MR/CT fusion for the first fraction followed by CT for fraction 2 and 3 is used at our center. The aim of this study is to evaluate the position of applicator intrauterine tube (IU) in relation to uterine serosa with each fraction of intracavitary high-dose-rate brachytherapy.

METHODS

Position of the applicator relative to uterus was measured from tip of the applicator (IU) to the top of uterus in the plane of IU and perpendicular to IU in anterior, posterior, left and right directions at the tip of IU, mid-point of the IU and 1 cm from the surface of vaginal ring. The mean absolute difference (±95 % confidence interval) between these positions at fraction 2 and 3 was calculated with fraction one as reference.

RESULTS

The mean absolute difference (±95 %) of the applicator relative to uterus was 2.7 ± 0.5 mm at the tip, 1.5 ± 4 mm at mid-point and 1.1 ± 0.3 mm at 1 cm from the surface of the ring.

CONCLUSION

This study shows that there is consistency in inter-fraction applicator position relative to uterus apart from at the tip and, therefore, in situations where high-risk clinical target volume (HRCTV) extends towards uterine fundus, MRI should be used for each fraction of brachytherapy planning to accurately define HRCTV.

Ultrasound guided conformal brachytherapy of cervix cancer: survival, patterns of failure, and late complications

Objective

The aim of this study was to report on the long-term results of transabdominal ultrasound guided conformal brachytherapy in patients with cervical cancer with respect to patterns of failures, treatment related toxicities and survival.

Methods

Three hundred and nine patients with cervical cancer who presented to Institute between January 1999 and December 2008 were staged with magnetic resonance imaging and positron emission tomography and treated with external beam radiotherapy and high dose rate conformal image guided brachytherapy with curative intent. Follow-up data relating to sites of failure and toxicity was recorded prospectively.

Results

Two hundred and ninety-two patients were available for analyses. The median (interquantile range) follow-up time was 4.1 years (range, 2.4 to 6.1 years). Five-year failure free survival and overall survival (OS) were 66% and 65%, respectively. Primary, pelvic, para-aortic, and distant failure were observed in 12.5%, 16.4%, 22%, and 23% of patients, respectively. In multivariate analysis, tumor volume and nodal disease related to survival, whereas local disease control and point A dose did not.

Conclusion

Ultrasound guided conformal brachytherapy of cervix cancer has led to optimal local control and OS. The Melbourne protocol compares favorably to the more technically elaborate and expensive GEC-ESTRO recommendations. The Melbourne protocol's technical simplicity with real-time imaging and treatment planning makes this a method of choice for treating patients with cervical cancer.

Dose-volume histogram parameters of high-dose-rate brachytherapy for Stage I-II cervical cancer (≤4cm) arising from a small-sized uterus treated with a point A dose-reduced plan

We investigated the rectal dose-sparing effect and tumor control of a point A dose-reduced plan in patients with Stage I-II cervical cancer (≤4 cm) arising from a small-sized uterus. Between October 2008 and August 2011, 19 patients with Stage I-II cervical cancer (≤4 cm) were treated with external beam radiotherapy (EBRT) for the pelvis and CT-guided brachytherapy. Seven patients were treated with brachytherapy with standard loading of source-dwell positions and a fraction dose of 6 Gy at point A (conventional brachy-plan). The other 12 patients with a small uterus close to the rectum or small intestine were treated with brachytherapy with a point A dose-reduction to match D2cc of the rectum and <6 Gy as the dose constraint ('point A dose-reduced plan') instead of the 6-Gy plan at point A ('tentative 6-Gy plan'). The total doses from EBRT and brachytherapy were added up and normalized to a biological equivalent dose of 2 Gy per fraction (EQD2). The median doses to the high-risk clinical target volume (HR-CTV) D90 in the conventional brachy-plan, tentative 6-Gy plan and point A dose-reduced plan were 62 GyEQD2, 80 GyEQD2 and 64 GyEQD2, respectively. The median doses of rectal D2cc in the corresponding three plans were 42 GyEQD2, 62 GyEQD2 and 51 GyEQD2, respectively. With a median follow-up period of 35 months, three patients developed Grade-1 late rectal complications and no patients developed local recurrence. Our preliminary results suggested that CT-guided brachytherapy using an individualized point A dose-reduced plan might be useful for reducing late rectal complications while maintaining primary tumor control.

CT based three dimensional dose-volume evaluations for high-dose rate intracavitary brachytherapy for cervical cancer

Background

In this study, high risk clinical target volumes (HR-CTVs) according to GEC-ESTRO guideline were contoured retrospectively based on CT images taken at the time of high-dose rate intracavitary brachytherapy (HDR-ICBT) and correlation between clinical outcome and dose of HR-CTV were analyzed.

Methods

Our study population consists of 51 patients with cervical cancer (Stages IB-IVA) treated with 50 Gy external beam radiotherapy (EBRT) using central shield combined with 2–5 times of 6 Gy HDR-ICBT with or without weekly cisplatin. Dose calculation was based on Manchester system and prescribed dose of 6 Gy were delivered for point A. CT images taken at the time of each HDR-ICBT were reviewed and HR-CTVs were contoured. Doses were converted to the equivalent dose in 2 Gy (EQD₂) by applying the linear quadratic model (α/β = 10 Gy).

Results

Three-year overall survival, Progression-free survival, and local control rate was 82.4%, 85.3% and 91.7%, respectively. Median cumulative dose of HR-CTV D₉₀ was 65.0 Gy (52.7-101.7 Gy). Median length from tandem to the most lateral edge of HR-CTV at the first ICBT was 29.2 mm (range, 18.0-51.9 mm). On univariate analysis, both LCR and PFS was significantly favorable in those patients D₉₀ for HR-CTV was 60 Gy or greater (p = 0.001 and 0.03, respectively). PFS was significantly favorable in those patients maximum length from tandem to edge of HR-CTV at first ICBT was shorter than 3.5 cm (p = 0.042).

Conclusion

Volume-dose showed a relationship to the clinical outcome in CT based brachytherapy for cervical carcinoma.

MRI findings at image guided adaptive cervix cancer brachytherapy: radiation oncologist's perspective

Magnetic resonance imaging (MRI) represents the reference imaging modality for image guided adaptive brachytherapy (IGABT) of cervix cancer. Accurate interpretation of pre-treatment MRI is required for proper understanding of the tumor extent and topography at IGABT. Planning and optimal timing of the application begins already before treatment, and may need to be adapted during external beam irradiation (EBRT) according to additional clinical and/or radiological findings. The level of MRI utilization in IGABT depends on the infrastructural capabilities of individual centers, ranging from no use at all to repetitive imaging during EBRT and each IGABT fraction. In this article, we summarize the role of different imaging modalities and practical aspects of MRI interpretation in cervix cancer IGABT, concentrating on the systematic evaluation of post-insertion images. MRI with the applicator in place from the radiation oncologist’s perspective should begin with immediate identification of eventual complications of the application procedure and assessment of the implant adequacy, followed by appropriate corrective measures in case of adverse findings. Finally, the tumor extent, topography, and treatment response should be evaluated in the context of initial clinical and radiological findings to allow for an appropriate selection and delineation of the target volumes.

Potential role of ultrasound imaging in interstitial image based cervical cancer brachytherapy

In 2012, more than 500,000 cases of cervical cancer were diagnosed worldwide. Over three quarters of these cases occur in less developed countries [1]. Advancements in image-guided brachytherapy are resulting in improved outcomes and reduced morbidity for women with this disease, but its worldwide adoption is hampered by lack of accessibility to advanced imaging techniques. Ultrasound is emerging as a potential option for tumor visualization, brachytherapy catheter placement, and treatment planning. While additional work is needed, ultrasound can potentially serve as the sole imaging modality for catheter insertion and planning. This paper will review our current knowledge on the use of ultrasound in interstitial brachytherapy treatment for cervical cancer.

Brachytherapy in the treatment of cervical cancer: a review

Dramatic advances have been made in brachytherapy for cervical cancer. Radiation treatment planning has evolved from two-dimensional to three-dimensional, incorporating magnetic resonance imaging and/or computed tomography into the treatment paradigm. This allows for better delineation and coverage of the tumor, as well as improved avoidance of surrounding organs. Consequently, advanced brachytherapy can achieve very high rates of local control with a reduction in morbidity, compared with historic approaches. This review provides an overview of state-of-the-art gynecologic brachytherapy, with a focus on recent advances and their implications for women with cervical cancer.

Imaging techniques for the evaluation of cervical cancer

Improvements in the treatment of cervical carcinoma have made it possible to offer optimal and personalised treatment. Cervical cancer staging is based on clinical examination and histological findings. Many diagnostic methods are used in clinical practice. Magnetic resonance imaging is considered the optimal method for staging cervical carcinoma because of its high accuracy in assessing local extension of disease and distant metastases. Ultrasound has gained increased attention in recent years; it is faster, cheaper, and more widely available than other imaging techniques, and is highly accurate in detecting tumour presence and evaluating local extension of disease. Magnetic resonance imaging and ultrasound are often used together with computed tomography or positron emission tomography combined with computed tomography to assess the whole body, a more accurate detection of pathological lymph nodes and metabolic information of the disease.

Dosimetric consequences of interobserver variability in delineating the organs at risk in gynecologic interstitial brachytherapy

PURPOSE

To investigate the dosimetric variability associated with interobserver organ-at-risk delineation differences on computed tomography in patients undergoing gynecologic interstitial brachytherapy.

METHODS AND MATERIALS

The rectum, bladder, and sigmoid of 14 patients treated with gynecologic interstitial brachytherapy were retrospectively contoured by 13 physicians. Geometric variability was calculated using κ statistics, conformity index (CIgen), and coefficient of variation (CV) of volumes contoured across physicians. Dosimetric variability of the single-fraction D0.1cc and D2cc was assessed through CV across physicians, and the standard deviation of the total EQD2 (equivalent dose in 2 Gy per fraction) brachytherapy dose (SD(TOT)) was calculated.

RESULTS

The population mean ± 1 standard deviation of κ, CIgen, and volume CV were, respectively: 0.77 ± 0.06, 0.70 ± 0.08, and 20% ± 6% for bladder; 0.74 ± 06, 0.67 ± 0.08, and 20% ± 5% for rectum; and 0.33 ± 0.20, 0.26 ± 0.17, and 82% ± 42% for sigmoid. Dosimetric variability was as follows: for bladder, CV = 31% ± 19% (SD(TOT) = 72 ± 64 Gy) for D0.1cc and CV = 16% ± 10% (SD(TOT) = 9 ± 6 Gy) for D2cc; for rectum, CV = 11% ± 5% (SD(TOT) = 16 ± 17 Gy) for D0.1cc and CV = 7% ± 2% (SD(TOT) = 4 ± 3 Gy) for D2cc; for sigmoid, CV = 39% ± 28% (SD(TOT) = 12 ± 18 Gy) for D0.1cc and CV = 34% ± 19% (SD(TOT) = 4 ± 4 Gy) for D2cc.

CONCLUSIONS

Delineation of bladder and rectum by 13 physicians demonstrated substantial geometric agreement and resulted in good dosimetric agreement for all dose-volume histogram parameters except bladder D0.1cc. Small delineation differences in high-dose regions by the posterior bladder wall may explain these results. The delineation of sigmoid showed fair geometric agreement. The higher dosimetric variability for sigmoid compared with rectum and bladder did not correlate with higher variability in the total brachytherapy dose but rather may be due to the sigmoid being positioned in low-dose regions in the cases analyzed in this study.

Image guided adaptive brachytherapy for cervical cancer: dose contribution to involved pelvic nodes in two cancer centers

PURPOSE

The goal of this study was to determine the dose contributions from image guided adaptive brachytherapy (IGABT) to individual suspicious pelvic lymph nodes (pLNN) in cervical cancer patients. Data were collected in two cancer centers, University of Pittsburgh Cancer Institute (UPCI) and University Medical Center Utrecht (UMCU).

MATERIAL AND METHODS

27 and 15 patients with node positive cervical cancer treated with HDR (high dose rate) or PDR (pulsed dose rate)-IGABT were analyzed. HDR-IGABT (UPCI) was delivered with CT/MRI compatible tandem-ring applicators with 5.0-6.0 Gy × five fractions. PDR-IGABT (UMCU) dose was delivered with Utrecht tandem-ovoid applicators with 32 × 0.6 Gy × two fractions. Pelvic lymph nodes with short axis diameter of ≥ 5 mm on pre-treatment MRI or PET-CT were contoured for all BT-plans. Dose contributions to individual pLNN expressed as D90 (dose to 90% of the volume) were calculated from dose-volume histograms as absolute and relative physical dose (% of the reference dose) for each fraction. For each node, the total dose from all fractions was calculated, expressed in EQD2 (equivalent total dose in 2 Gy fractions).

RESULTS

Fifty-seven (UPCI) and 40 (UMCU) individual pLNN were contoured. The mean D90 pLNN was 10.8% (range 5.7-25.1%) and 20.5% (range 6.8-93.3%), respectively, and therefore different in the two centers. These values translate into 2.7 Gy (1.3-6.6 Gy) EQD2 and 7.1 Gy (2.2-36.7 Gy) EQD2, respectively. Differences are caused by the location of the individual nodes in relation to the spatial dose distribution of IGABT, differences in total dose administered and radiobiology (HDR versus PDR).

CONCLUSIONS

The IGABT dose contribution to individual pelvic nodes depends on patient and treatment related factors, and varies considerably.

A new laparoscopic method of bowel radio-protection before pelvic chemoradiation of locally advanced cervix cancers

BACKGROUND

Chemoradiation therapy (CRT) has become the mainstay of locally advanced cervical carcinomas (LACC). However, the price to pay is a significant rate of both early and late colo-rectal toxicities, which may impact on survivors' quality of life. To reduce the incidence of such complications, we suggest a simple technique of pelvic radioprotection.

MATERIALS AND METHODS

An omental flap is created which is placed to fill the Douglas pouch to both increase the space between rectum and uterine cervix and prevent small bowel to fall in and to be exposed to radiation. In addition, a long sigmoid loop is retracted and fixed in the left paracolic gutter to prevent its irradiation as well.

RESULTS

From May 2011 to May 2012, 51 successive LACC patients were offered this procedure in addition of a laparoscopic staging. All but 2 with too small an omentum benefitted from omentoplasty, while sigmoidopexy was performed in all but one patient with a long and free sigmoid loop. No immediate adverse effect was observed. The volume of retro-uterine omental flap averaged 7.17 ± 3.79 cm(3). Sequential measurements of the utero-rectal space throughout CRT duration showed a real and durable increase in the distance between these organs, resulting in a drop in the dose of irradiation to recto-sigmoid. With 10 ± 4.5-month median follow-up, we did not observe any rectal or small bowel early or late adverse effects of CRT.

CONCLUSIONS

Although this series is preliminary, this simple procedure, feasible by laparoscopy (or laparotomy), seems effective to prevent recto-sigmoid as well as small bowel from radio-induced complications due to pelvic CRT.

CT-based interstitial brachytherapy in advanced gynecologic malignancies: outcomes from a single institution experience

PURPOSE

To evaluate the clinical outcomes of women receiving a "short" course of high-dose-rate gynecologic interstitial brachytherapy (HDR-ISBT) boost with CT-based 3D planning.

METHODS AND MATERIALS

Forty-seven women with no prior radiation received HDR-ISBT from August 2004 to February 2012. The mean external beam radiotherapy dose was 45 Gy. A mean HDR-ISBT boost dose of 18.4 Gy was delivered over 2-4 fractions. Dose volume histograms (DVHs) were computed for organs at risk and clinical target volume.

RESULTS

With a median followup of 34.8 months, the 3-year local control rate was 68%. Sixteen patients were identified to have tumor recurrence (including eight local). The median time to any recurrence was 26.8 months. Relapse-free survival and overall survival at 3 years was 65% and 73%, respectively. Ten patients experienced Grade 3 late toxicity, mainly vaginal (5) and proctitis (3). The mean prescription volume (V100) was 85 cc and the mean D90 to CTV was 98%. The mean cumulative dose to tumor was 69.9 Gy (equivalent dose in 2 Gy). The mean cumulative equivalent dose in 2 Gy to D2cc of bladder and rectum was 60.9 Gy and 63.0 Gy, respectively.

CONCLUSION

A "short" course HDR-ISBT is effective, safe, and convenient with acceptable local control and toxicity. Higher dose per fraction is similar to an external beam radiotherapy stereotactic boost with the inherent advantages of brachytherapy. A shorter overall time for HDR-ISBT means less time that patients are immobilized and in hospital, making it less resource intensive than a longer course.

A study to assess the feasibility of using CT (±diagnostic MRI) instead of MRI at brachytherapy in image guided brachytherapy in cervical cancer

Purpose

To compare the contours and dose volume histograms (DVH) parameters of the high-risk clinical target volume (HRCTV) contoured on computed tomography (CT) using clinical findings at brachytherapy, clinical findings at brachytherapy with magnetic resonance imaging (MRI) at diagnosis and HRCTV defined on MRI at brachytherapy in cervical cancer patients.

Materials and methods

Fifteen patients undergoing MRI-guided image-based brachytherapy underwent both CT and MRI after applicator insertion. Two sets of contours were defined on CT. In the first set, the HRCTV was defined with the help of clinical findings at brachytherapy (CT-HRCTV). In the second set, HRCTV was defined with MRI at diagnosis and clinical findings at brachytherapy (CT-HRCTVdmri). This was compared with the HRCTV defined on MRI at brachytherapy (MR-HRCTV). The doses to the organs at risk (OARs) were compared for CT and MRI.

Results

A significant overestimation of the maximum width and width at point A was observed for CT-HRCTV (p −0·00; 0·00) and CT-HRCTVdmri (p −0·03; 0·01), respectively. The height was underestimated with CT-HRCTV in patients with intrauterine disease extension. For a single fraction, the mean difference in the D90 for the CT contours was <1 Gy. The doses to the OARs were comparable.

Conclusions

CT may be an alternative when facilities for MRI image-based brachytherapy are lacking, provided at least one MRI is available before brachytherapy.

Distant metastasis in patients with cervical cancer after primary radiotherapy with or without chemotherapy and image guided adaptive brachytherapy

OBJECTIVE

The aim of this study is to investigate patterns of distant relapse after primary radiochemotherapy in cervical cancer patients.

METHODS

All patients with cervical cancer treated in curative intent with external beam radiotherapy +/- chemotherapy and image-guided adaptive brachytherapy between January 1998 and June 2009 at the Medical University of Vienna were included in this retrospective analysis. Patients with locoregional recurrences were excluded from this study. Presence, site of and time to distant metastases were recorded. For identifying prognostic factors, uni- and multivariate analyses using Cox regression analysis were performed. Based on the result from the multivariate analysis, patients were stratified into a high and a low risk group. The Kaplan-Meier method was used to estimate distant-metastasis-free-survival in the overall cohort, in the risk groups and for analysing the impact of chemotherapy within the risk groups.

RESULTS

A total number of 189 patients were included in this study. After a median follow-up of 54 months, 49 patients developed distant metastases. Overall, distant-metastasis-free-survival 5 years after treatment was 73%. FIGO stage, lymph node status and the extent of tumour regression during treatment were significant predictors for distant metastasis. Distant-metastasis-free-survival 5 years after treatment was 91% and 60% in the low and high risk groups, respectively. The number of the cycles of chemotherapy had a significant impact on the occurrence of distant metastasis in high risk patients, but not in low risk patients.

CONCLUSION

Patients with high risk factors have a 40% probability of developing distant metastasis within 5 years. In these patients, decreasing the number of cycles of cisplatin may increase their probability of developing distant metastasis.

Impact of boost irradiation on pelvic lymph node control in patients with cervical cancer

Radiation therapy (RT) for metastatic pelvic lymph nodes (PLNs) is not well established in cervical cancer. In this study the correlation between size of lymph nodes and control doses of RT was analyzed. Between January 2002 and December 2007, 245 patients with squamous cell carcinoma of the cervix treated with a combination of external beam irradiation with or without boost irradiation and high-dose rate brachytherapy were investigated. Size of lymph node was measured by computed tomography before RT and just after 50 Gy RT. Of the 245 patients, 78 had PLN metastases, and a total of 129 had enlarged PLNs diagnosed as metastases; 22 patients had PLN failure. The PLN control rate at 5 years was 79.5% for positive cases and 95.8% for negative cases. In cases with positive PLNs, 12 of 129 nodes (9.3%) developed recurrences. There was significant correlation between PLN control rate and size of PLN after 50 Gy (<10 mm: 96.7%, ≥ 10 mm: 75.7 % (P<0.001)). In addition, the recurrence in these poor-response nodes was significantly correlated with dose of RT. Nine of 16 nodes receiving ≤ 58 Gy had recurrence, but none of 21 nodes receiving > 58 Gy had recurrence (P = 0.0003). These results suggested that the response of lymph nodes after RT was a more significant predictive factor for recurrence than size of lymph node before RT, and poor-response lymph nodes might require boost irradiation at a total dose of > 58 Gy.

Locally advanced cervical cancer in renal transplant patients: a dilemma between control and toxicity

PURPOSE

Treatment of locally advanced cervical cancer in patients with a renal graft requires precautions. The graft is usually in a pelvic position, close to the clinical target volume (CTV). Preserving the graft while ensuring local control is a challenge we have faced in two occasions. We report our experience.

METHODS AND MATERIALS

We report the cases of 2 patients treated at our institution with a modified workup and therapeutic approach compared with our standard approach. The clinical and technical aspects of both treatments were systematically reviewed and contrasted with reports previously cited in the literature.

RESULTS

The first patient received external beam conformal radiotherapy (total dose: 30 Gy in the pelvis) followed by two sessions of MRI-guided brachytherapy (2 × 15 Gy to 90% of the intermediate risk CTV). The second one received pelvic intensity-modulated radiation therapy (total dose: 45 Gy) followed by MRI-guided brachytherapy delivering 15 Gy to 90% of the intermediate risk CTV. Both patients had a complete response and were still in remission more than 2 years after treatment while retaining their graft. No severe late toxicity was reported.

CONCLUSIONS

External beam radiotherapy followed by brachytherapy is feasible in locally advanced cervical cancer, despite the presence of a kidney graft near the targets. Image-guided adaptive brachytherapy allowed an accurate evaluation of the dose distribution, reaching the recommended treatment thresholds with optimal protection of the graft.

Volume-based pulsed-dose-rate brachytherapy boosting concurrent chemoradiation as a definitive treatment modality in cervical cancer

PURPOSE

To report the treatment outcomes and treatment-induced adverse events (AEs) of concomitant chemoradiotherapy boosted with pulsed-dose-rate brachytherapy using volume-based two-dimensional planning in patients with cervical cancer.

PATIENTS AND METHODS

After obtaining the institutional review board approval, patients with FIGO Stages IB to IIIB cervical cancer, treated from January 2006 to December 2008 consecutively, were included. Volume-based planning was used and entailed defining an envelope around the tumor on a two-dimensional image and prescribing the dose to this envelope and reporting the dose of the isodose of 60 Gy. Patients and tumor characteristics, dosimetric parameters, AEs and treatment outcomes, local control rate, distant metastases rate, progression-free survival, and overall survival are reported.

RESULTS

The study included 95 patients; the median age is 50 years. The median tumor size is 50cc (range, 25-78cc). Median brachytherapy dose delivered to the envelope is 20 Gy (range, 15-35 Gy), and median volume encompassed by 60 Gy isodose curve is 137cc (range, 26-365cc). The 3-year overall survival, progression-free survival, local control rate, and distant metastases rate were 83.8%, 72.4%, 84.8%, and 15.4%, respectively. Gastrointestinal and genitourinary Grade 3 and 4 acute AEs were reported in 11.6% and 3.3% and chronic Grade 3 and 4 AEs were reported in 3.2% and 4.2% of all patients, respectively.

CONCLUSIONS

Chemoradiotherapy followed by pulsed-dose-rate brachytherapy boost is effective and tolerable treatment modality for locally confined cervical cancer.

Equivalence of Gyn GEC-ESTRO guidelines for image guided cervical brachytherapy with EUD-based dose prescription

Background

To establish a generalized equivalent uniform dose (gEUD) -based prescription method for Image Guided Brachytherapy (IGBT) that reproduces the Gyn GEC-ESTRO WG (GGE) prescription for cervix carcinoma patients on CT images with limited soft tissue resolution.

Methods

The equivalence of two IGBT planning approaches was investigated in 20 patients who received external beam radiotherapy (EBT) and 5 concomitant high dose rate IGBT treatments. The GGE planning strategy based on dose to the most exposed 2 cm³ (D2cc) was used to derive criteria for the gEUD-based planning of the bladder and rectum. The safety of gEUD constraints in terms of GGE criteria was tested by maximizing dose to the gEUD constraints for individual fractions.

Results

The gEUD constraints of 3.55 Gy for the rectum and 5.19 Gy for the bladder were derived. Rectum and bladder gEUD-maximized plans resulted in D2cc averages very similar to the initial GGE criteria. Average D2ccs and EUDs from the full treatment course were comparable for the two techniques within both sets of normal tissue constraints. The same was found for the tumor doses.

Conclusions

The derived gEUD criteria for normal organs result in GGE-equivalent IGBT treatment plans. The gEUD-based planning considers the entire dose distribution of organs in contrast to a single dose-volume-histogram point.

Interfractional change of high-risk CTV D90 during image-guided brachytherapy for uterine cervical cancer

The purpose of this study was to evaluate interfractional changes of the minimum dose delivered to 90% of the high-risk clinical target volume (HR-CTV D90) and D2cc of the bladder and rectum during brachytherapy for uterine cervical cancer patients. A total of 52 patients received external beam radiotherapy and high-dose-rate intracavitary brachytherapy (ICBT). For each of four ICBT applications, a pelvic CT scan was performed and the HR-CTV was delineated. Retrospectively, these patients were divided into two groups: (i) the standard dose group with 6 Gy to point A in each ICBT, and (ii) the adaptive dose group with a modified dose to point A to cover the HR-CTV with the 6-Gy isodose line as much as possible. The HR-CTV D90 was assessed in every session, and analyzed as interfractional changes. In the standard dose group, the interfractional changes of the HR-CTV D90 showed a linear increase from the first to the third of the four ICBT (average 6.1, 6.6, 7.0 and 7.1 Gy, respectively). In contrast, those of the adaptive dose group remained almost constant (average 7.2, 7.2, 7.3 and 7.4 Gy, respectively). Especially, in the case of a large HR-CTV volume (≥35 cm(3)) at first ICBT, the total HR-CTV D90 of the adaptive dose group with brachytherapy was significantly higher than that of the standard dose group. There were no significant differences in total D2cc in bladder and rectum between the two groups. Image-guided adaptive brachytherapy based on interfractional tumor volume change improves the dose to the HR-CTV while keeping rectal and bladder doses within acceptable levels.

Dose-escalation study of carbon ion radiotherapy for locally advanced squamous cell carcinoma of the uterine cervix (9902)

OBJECTIVE

The authors performed phase I/II clinical trial to evaluate the toxicity and efficacy of carbon ion radiotherapy (C-ion RT) for locally advanced squamous cell carcinoma of the uterine cervix.

METHODS

Between April 2000 and January 2006, 22 patients for Protocol 9902 were treated with C-ion RT. The number of patients with stage IIB, IIIB, and IVA diseases was 1, 18, and 3, respectively. All patients had bulky tumors measuring 4.0-12.0 cm (median 6.2 cm). The whole pelvic dose was fixed at 39.0 GyE for 13 fractions, and additional 15.0 GyE for 5 fractions was given to the gross tumor volume (GTV) and surrounding tissues. With regard to local boost, a dose-escalation study was planned for 2 fractions to GTV. Total dose to the cervical tumor was 64.0-72.0 GyE for 20 fractions.

RESULTS

All patients completed the scheduled therapy and no patient developed Grade 2 or higher acute toxicity. There was no Grade 3 or higher late complications at each dose. The 5-year overall survival rate and local control rate were 50.0% and 68.2%, respectively. Seven out of the 16 patients who received 64.0-68.0 GyE developed local recurrences, but all patients who received 72.0 GyE maintained local control.

CONCLUSIONS

There were no severe acute or late complications in this trial. C-ion RT has the potential to improve the treatment for locally advanced bulky cervical cancer by applying a total dose of 72.0 GyE, with the results lending incentive to further investigations to confirm the therapeutic efficacy.

Evidence based radiation oncology with existing technology

AIM

To assess the real contribution of modern radiation therapy (RT) technology in the more common tumoral types in Central America, Caribbean and South America.

BACKGROUND

RT is an essential tool in the management of cancer. RT can be either palliative or of curative intent. In general, for palliative radiotherapy, major technologies are not needed.

MATERIALS AND METHODS

We analyzed the contribution of RT technology based on published evidence for breast, lung, gastric, gallbladder, colorectal, prostate and cervix cancer in terms of disease control, survival or toxicity with especial focus on Latin America.

RESULTS

Findings indicate that three dimensional conformal radiation therapy (3D RT) is the gold standard in most common type of cancer in the studied regions. Prostate cancer is probably the pathology that has more benefits when using new RT technology such as intensity modulated radiation therapy (IMRT) versus 3DRT in terms of toxicity and biochemical progression-free survival.

CONCLUSIONS

In light of the changes in technology, the ever-increasing access of developing countries to such technology, and its current coverage in Latin America, any efforts in this area should be aimed at improving the quality of the radiotherapy departments and centers that are already in place.

High-risk clinical target volume delineation in CT-guided cervical cancer brachytherapy: impact of information from FIGO stage with or without systematic inclusion of 3D documentation of clinical gynecological examination

PURPOSE

The aim of the study was to improve computed tomography (CT)-based high-risk clinical target volume (HR CTV) delineation protocols for cervix cancer patients, in settings without any access to magnetic resonance imaging (MRI) at the time of brachytherapy. Therefore the value of a systematic integration of comprehensive three-dimensional (3D) documentation of repetitive gynecological examination for CT-based HR CTV delineation protocols, in addition to information from FIGO staging, was investigated. In addition to a comparison between reference MRI contours and two different CT-based contouring methods (using complementary information from FIGO staging with or without additional 3D clinical drawings), the use of standardized uterine heights was also investigated.

MATERIAL AND METHODS

Thirty-five cervix cancer patients with CT- and MR-images and 3D clinical drawings at time of diagnosis and brachytherapy were included. HR CTV(stage) was based on CT information and FIGO stage. HR CTV(stage + 3Dclin) was contoured on CT using FIGO stage and 3D clinical drawing. Standardized HR CTV heights were: 1/1, 2/3 and 1/2 of uterine height. MRI-based HR CTV was delineated independently. Resulting widths, thicknesses, heights, and volumes of HR CTV(stage), HR CTV(stage + 3Dclin) and MRI-based HR CTV contours were compared.

RESULTS

The overall normalized volume ratios (mean ± SD of CT/MRI(ref) volume) of HR CTV(stage) and HR stage + 3Dclin were 2.6 (± 0.6) and 2.1 (± 0.4) for 1/1 and 2.3 (± 0.5) and 1.8 (± 0.4), for 2/3, and 1.9 (± 0.5) and 1.5 (± 0.3), for 1/2 of uterine height. The mean normalized widths were 1.5 ± 0.2 and 1.2 ± 0.2 for HR CTV(stage) and HR CTV(stage + 3Dclin), respectively (p < 0.05). The mean normalized heights for HR CTV(stage) and HR CTV(stage + 3Dclin) were both 1.7 ± 0.4 for 1/1 (p < 0.05.), 1.3 ± 0.3 for 2/3 (p < 0.05) and 1.1 ± 0.3 for 1/2 of uterine height.

CONCLUSION

CT-based HR CTV contouring based on FIGO stage alone leads to large overestimation of width and volume. Target delineation accuracy can systematically improve through incorporation of additional information from comprehensive 3D documentation of repetitive gynecological examination in the contouring protocol, and thus help to improve the accuracy of dose optimization in settings with limited access to imaging facilities at the time of brachytherapy. If CT information is only available, minimum 2/3 of uterine height may be a good surrogate for the height of HR CTV.

Voxelwise comparison of perfusion parameters estimated using dynamic contrast enhanced (DCE) computed tomography and DCE-magnetic resonance imaging in locally advanced cervical cancer

PURPOSE

Dynamic contrast enhanced (DCE) imaging has gained interest as an imaging modality for assessment of tumor characteristics and response to cancer treatment. However, for DCE-magnetic resonance imaging (MRI) tissue contrast enhancement may vary depending on imaging sequence and temporal resolution. The aim of this study is to compare DCE-MRI to DCE-computed tomography (DCE-CT) as the gold standard.

MATERIAL AND METHODS

Thirteen patients with advanced cervical cancer were scanned once prior to chemo-radiation and during chemo-radiation with DCE-CT and -MRI in immediate succession. A total of 22 paired DCE-CT and -MRI scans were acquired for comparison. Kinetic modeling using the extended Tofts model was applied to both image series. Furthermore the similarity of the spatial distribution was evaluated using a Γ analysis. The correlation between the two imaging techniques was evaluated using Pearson's correlation and the parameter means were compared using a Student's t-test (p < 0.05).

RESULTS

A significant positive correlation between DCE-CT and -MRI was found for all kinetic parameters. The results showing the best correlation with the DCE-CT-derived parameters were obtained using a population-based input function for MRI. The median Pearson's correlations were: volume transfer constant K(trans) (r = 0.9), flux rate constant kep (r = 0.77), extracellular volume fraction ve (r = 0.58) and blood plasma volume fraction vp (r = 0.83). All quantitative parameters were found to be significantly different as estimated by DCE-CT and -MRI. The Γ analysis in normalized maps revealed that 45% of the voxels failed to find a voxel with the corresponding value allowing for an uncertainty of 3 mm in position and 3% in value (Γ3,3). By reducing the criteria, the Γ-failure rates were: Γ3,5 (37% failure), Γ3,10 (26% failure) and at Γ3,15 (19% failure).

CONCLUSION

Good to excellent correlations but significant bias was found between DCE-CT and -MRI. Both the Pearson's correlation and the Γ analysis proved that the spatial information was similar when analyzing the two sets of DCE data using the extended Tofts model. Improvement of input function sampling is needed to improve kinetic quantification using DCE-MRI.

Magnetic resonance imaging for assessment of parametrial tumour spread and regression patterns in adaptive cervix cancer radiotherapy

PURPOSE

To investigate the impact of magnetic resonance imaging (MRI)-morphologic differences in parametrial infiltration on tumour response during primary radiochemotherapy in cervical cancer.

MATERIAL AND METHODS

Eighty-five consecutive cervical cancer patients with FIGO stages IIB (n = 59) and IIIB (n = 26), treated by external beam radiotherapy (± chemotherapy) and image-guided adaptive brachytherapy, underwent T2-weighted MRI at the time of diagnosis and at the time of brachytherapy. MRI patterns of parametrial tumour infiltration at the time of diagnosis were assessed with regard to predominant morphology and maximum extent of parametrial tumour infiltration and were stratified into five tumour groups (TG): 1) expansive with spiculae; 2) expansive with spiculae and infiltrating parts; 3) infiltrative into the inner third of the parametrial space (PM); 4) infiltrative into the middle third of the PM; and 5) infiltrative into the outer third of the PM. MRI at the time of brachytherapy was used for identifying presence (residual vs. no residual disease) and signal intensity (high vs. intermediate) of residual disease within the PM. Left and right PM of each patient were evaluated separately at both time points. The impact of the TG on tumour remission status within the PM was analysed using χ(2)-test and logistic regression analysis.

RESULTS

In total, 170 PM were analysed. The TG 1, 2, 3, 4, 5 were present in 12%, 11%, 35%, 25% and 12% of the cases, respectively. Five percent of the PM were tumour-free. Residual tumour in the PM was identified in 19%, 68%, 88%, 90% and 85% of the PM for the TG 1, 2, 3, 4, and 5, respectively. The TG 3-5 had significantly higher rates of residual tumour in the PM in comparison to TG 1 + 2 (88% vs. 43%, p < 0.01).

CONCLUSION

MRI-morphologic features of PM infiltration appear to allow for prediction of tumour response during external beam radiotherapy and chemotherapy. A predominantly infiltrative tumour spread at the time of diagnosis resulted in a significantly higher rate of residual tumour in the PM at the time of brachytherapy in comparison to a predominantly expansive tumour spread.

MRI-guided adaptive radiotherapy in locally advanced cervical cancer from a Nordic perspective

BACKGROUND

The first Nordic protocol for three-dimensional (3D) planned radiotherapy in locally advanced cervical cancer was the prospective NOCECA study (1994-2000). NOCECA consisted of computed tomography (CT)-based 3D conformal external beam radiotherapy (EBRT) with a simultaneous integrated boost (SIB) to the primary tumour combined with brachytherapy (BT) based on x-ray imaging. In NOCECA the planning aim was to achieve 80 Gy at point A from EBRT and BT combined. However, the balance of dose between EBRT and BT was determined by tumour size at diagnosis with more EBRT dose given to point A and less by BT in more advanced stages. In 2005 image-guided adaptive brachytherapy (IGABT) based on magnetic resonance imaging (MRI) and optimisation of the BT dose distribution to the remaining tumour and cervix at time of BT (HR CTV) was introduced in Aarhus. EBRT remained like in NOCECA until 2008 when the SIB to the primary tumour was abandoned and IMRT was introduced as routine technique. In this study, we report outcome of our first five-year experience with IGABT using our NOCECA cohort as reference.

MATERIAL AND METHODS

The NOCECA cohort comprising 99 patients was compared with 140 consecutive patients treated by IGABT. Patients with para-aortic nodes were excluded in NOCECA but were present in 9% of the patients treated with IGABT. No patient in NOCECA received chemotherapy whereas concomitant cisplatin was given to 79% of the IGABT patients.

RESULTS

With IGABT actuarial local control was 91% at three years. When comparing NOCECA with IGABT overall survival was significantly improved from 63% to 79% (p = 0.005). In parallel, both moderate and severe late morbidity were reduced by about 50% (p = 0.02).

CONCLUSION

Introduction of IGABT reduced morbidity and generated a very high rate of local control, which likely has improved survival by at least as much as concomitant chemotherapy.

The implementation of a PDR 3D-guided gynaecological brachytherapy service in a UK centre

Background

Due to the discontinuation of the widely used low-dose rate (LDR) Caesium afterloader units, many centres in the past 10 years have moved from LDR Selectron treatments to Iridium 192 afterloaders. While the majority of UK centres have opted for high-dose rate (HDR) units, the Christie have invested in two pulsed dose rate (PDR) afterloaders alongside a move to full 3D-planned gynaecological brachytherapy.

Purpose

To share the experience and learning curve involved in the implementation of a 3D-guided PDR brachytherapy service.

Methods

The specific logistical and practical challenges of implementing a PDR service are discussed alongside the more general challenges of implementing 3D-guided magnetic resonance (MR) based brachytherapy. A multidisciplinary approach was undertaken to streamline the patient pathway and give all disciplines a forum to discuss service improvements and resolve problems.

Conclusions

The lessons learned throughout this experience can inform the decisions of departments that may wish to implement a PDR service or indeed a 3D image-guided HDR brachytherapy service in the future. The focus on the utilisation of lean principles to the patient pathway, improved multidisciplinary working and enhancing service efficiency is of interest to all centres.