Places respectives de la radiothérapie et de la chirurgie dans les cancers du col utérin

The treatment of cervical cancer patients relies on surgery and radiotherapy (according to the stage) and requires a multimodal discussion before any treatment to avoid adding the morbidities of each individual intervention and to optimize functional and oncological outcomes. The places of surgery and radiotherapy have been highlighted in recent international guidelines. For early stage tumors, an exclusive surgery with or without fertility sparing (according to well defined criteria) is the therapeutic standard. For tumors with risk factors (measuring more than 2 cm in size and/or presence of lymphovascular invasion) a preoperative brachytherapy can be proposed to minimize the need for postoperative external beam radiotherapy and optimize local control. For locally advanced disease, the standard treatment relies on chemoradiation followed by a brachytherapy boost. A primary paraaortic lymph node dissection may guide radiotherapy volumes and is useful to identify patients requiring a para-aortic radiotherapy. The technical evolutions of surgical approaches and technological improvement of radiotherapy and brachytherapy should be analyzed in the context of prospective studies. We review the literature on the respective places of radiotherapy and surgery for the treatment of cervical cancer.     

Development and characterization of an anthropomorphic breast phantom for permanent breast seed implant brachytherapy credentialing

PurposeTo develop an anthropomorphic breast phantom for use in credentialing of permanent breast seed implant brachytherapy.Methods and MaterialsA representative external contour and target volume was used as the basis of mold manufacturing for anthropomorphic breast phantom development. Both target and normal tissue were composed of gel-like materials that provide suitable computed tomography and ultrasound contrast for brachytherapy delivery. The phantoms were evaluated for consistency in construction (target location) and Hounsfield unit (computed tomography contrast). For both target and normal tissue, the speed of sound was measured and compared to the image reconstruction algorithm's expectation value. Five phantoms were imaged preimplant and postimplant to assess interphantom similarity as well as to evaluate the uncertainty in quantifying seed position.ResultsThe average Hounsfield units of the target and normal tissue gels is −146 ± 5 and 23 ± 1, respectively. The average speed of sound of the target and normal tissue gels is 1485 ± 7 m/s and 1558 ± 9 m/s, respectively, resulting in an estimated 0.4 mm uncertainty in image guidance. The registration/deformation uncertainty was determined to be 0.8 mm. The standard combined uncertainty in assessing seed position spatial accuracy, also including a 0.9 mm estimate based on literature for seed localization, is estimated to be 1.3 mm.ConclusionsThe development of the anthropomorphic breast phantom and evaluation of both the consistency as well as overall seed position uncertainty illustrates the suitability of this phantom for use in brachytherapy end-to-end delivery and implant accuracy evaluation. When evaluating a user's implant accuracy, we estimate a standard combined uncertainty of 1.3 mm.     

Comparison between the ICRU rectal point and modern volumetric parameters in brachytherapy for locally advanced cervical cancer

PurposeThe implementation of image-guided brachytherapy in cervical cancer raises the problem of adapting the experience acquired with 2D brachytherapy to this technique. The GEC-ESTRO (Groupe européen de curiethérapie – European Society for Radiotherapy and Oncology) has recommended reporting the dose delivered to the rectum in the maximally exposed 2 cm³ volume, but so far, the recommended dose constraints still rely on 2D data. The aim of this study was to evaluate the relationship between the doses evaluated at the ICRU rectal point and modern dosimetric parameters.Material and methodsFor each patient, dosimetric parameters were generated prospectively at the time of dosimetry and were reported. For analysis, they were converted in 2 Gy equivalent doses using an α/β ratio of 3 with a half-time of repair of 1.5 hours.ResultsThe dosimetric data from 229 consecutive patients treated for locally advanced cervical cancer was analyzed. The mean dose calculated at ICRU point (DICRU) was 55.75 Gy ± 4.15, while it was 59.27 Gy ± 6.16 in the maximally exposed 2 cm³ of the rectum (P = 0.0003). The D2 cm³ was higher than the DICRU in 78% of the cases. The mean difference between D2 cm³ and DICRU was 3.53 Gy ± 4.91. This difference represented 5.41% ± 7.40 of the total dose delivered to the rectum (EBRT and BT), and 15.49% ± 24.30 of the dose delivered when considering brachytherapy alone. The two parameters were significantly correlated (P = 0.000001), and related by the equation: D2 cm³ = 0.902 × DICRU + 0.984. The r² coefficient was 0.369.ConclusionIn this large cohort of patients, the DICRU significantly underestimates the D2 cm³. This difference probably results from the optimization process itself, which consists in increasing dwell times above the ICRU point in the cervix. Considering these findings, caution must be taken while implementing image-guided brachytherapy and dose escalation.     

Perioperative high-dose-rate brachytherapy in locally advanced and recurrent gynecological cancer: Final results of a Phase II trial

PurposeTo determine the long-term results of a Phase II trial of perioperative high-dose-rate brachytherapy (PHDRB) in primary advanced or recurrent gynecological cancer.Methods and MaterialsFifty patients with locally advanced and recurrent gynecological cancer suitable for salvage surgery were included. Unirradiated patients (n = 25) received preoperative chemoradiation followed by surgery and PHDRB (16–24 Gy). Previously irradiated patients (n = 25) received surgery and PHDRB alone (32–40 Gy).ResultsMedian followup was 11.5 years. Eight unirradiated patients (32%) developed Grade ≥3 toxic events including two fatal events. Local and locoregional control rates at 16 years were 87.3% and 78.9%, respectively. Sixteen-year disease-free and overall survival rates were 42.9% and 46.4%, respectively. Ten previously irradiated patients (40.0%) developed Grade ≥3 adverse events, including four fatal events. Local and locoregional control rates at 14 years were 59.6% and 42.6%, respectively. Fourteen-year disease-free and overall survival rates were 16.0% and 19.2%, respectively.ConclusionsPHDRB allows effective salvage of a subset of unfavorable gynecological tumors with high-risk surgical margins. Toxicity was unacceptable at the initial dose levels but deescalation resulted in the absence of severe toxicity without a negative impact on locoregional control. A substantial percentage of patients remain alive and controlled at >10 years including a few previously irradiated cases with positive margins.     

In vivo dosimetry in gynecological applications—A feasibility study

PurposeTo investigate the feasibility of in vivo dosimetry using microMOSFET dosimeters in patients treated with brachytherapy using two types of gynecological applicators.Methods and MaterialsIn this study, a microMOSFET was placed in an empty needle of an Utrecht Interstitial Fletcher applicator or MUPIT (Martinez Universal Perineal Interstitial Template) applicator for independent verification of treatment delivery. Measurements were performed in 10 patients, with one to three microMOSFETs per applicator and repeated for one to four fractions, resulting in 50 in vivo measurements. Phantom measurements were used to determine characteristics of the microMOSFETs.ResultsPhantom measurements showed a linear relationship between dose and microMOSFET threshold voltage, and a calibration coefficient (mV/cGy) was determined. Reproducibility of repeated 50 cGy irradiations was 2% (1 standard deviation). Distance and angle dependencies were measured and correction factors were determined. Subsequently, three microMOSFETs were placed in a phantom to measure a validation plan. The difference between predicted and measured dose was less than the measurement uncertainty (±9%, 2 standard deviations). In vivo measurements were corrected for distance and angle dependencies. Differences between predicted and measured dose in the patients were smaller than the measurement uncertainty for the majority of the measurements.ConclusionsIn vivo dosimetry using microMOSFETs in MUPIT and Utrecht Interstitial Fletcher applicators has proved to be feasible. Reimaging should be performed after detection of differences larger than 10% between predicted and measured dose to verify the applicator configuration. Movement of the applicator relative to the target or organs at risk is undetectable with this method.     

Traitements de rattrapage après irradiation prostatique : place de l’urologue

The management of recurrent prostate cancer after radiotherapy or brachytherapy is non-standardized and rapidly evolving. Local recurrence is observed on average in 30% of cases several years following irradiation. A key challenge is to determine the site of recurrence and imaging (MRI and PET choline) coupled to prostate biopsies are important to confirm the local character. Salvage therapy performed by the urologist can then control the situation. Radical prostatectomy subject to strict technical conditions is one of the most efficient local treatments, however it comes at the cost of significant urinary morbidity; minimally invasive therapies (focused ultrasound and cryotherapy) have also their place in specific indications. Each clinical situation should be discussed in pluridisciplinary meetings integrating the oncologic and functional status at recurrence, the risk/benefit ratio of each treatment, the patient's wishes and probability of survival.     

Brachytherapy and fertility

Fertility is a major part of the global care of patients treated for cancer. A new discipline known as oncofertility has emerged in some countries. Although the relationship between chemotherapy and external radiotherapy and fertility has been studied and reported, there is only scarce data available on brachytherapy. This systematic review aims to report available knowledge on the impact of brachytherapy on fertility. Specific consultations should be considered before brachytherapy to inform patients about their fertility preservation options.