T. Messai

PHYSICS CONTRIBUTIONS AND CLINICAL OUTCOME WITH 3D-MRI-BASED PULSED-DOSE-RATE INTRACAVITARY BRACHYTHERAPY IN CERVICAL CANCER PATIENTS

PURPOSE To assess the physics contributions and clinical outcome with three-dimensional magnetic resonance imaging-guided pulsed-dose-rate (PDR) intracavitary brachytherapy in cervical cancer patients. METHODS AND MATERIALS The data from 45 patients with primary locally advanced cervical carcinoma were analyzed. The median tumor cervical volume was 64.0 cm(3) (range, 3-178). Of the 45 patients, 24 (53%) had histologic and/or radiologic pelvic involvement. After pelvic with or without para-aortic concomitant chemoradiotherapy, a PDR brachytherapy boost was delivered to a three-dimensional magnetic resonance imaging-based clinical target volume, taking into account the dose-volume constraints for critical organs and optimization of the target volume coverage. RESULTS At a median follow-up of 26 months (range, 9-47), the 2-year overall survival and disease-free survival rate was 78% and 73%, respectively. At the last follow-up visit, the disease of all patients remained locally controlled. Adding external beam radiotherapy and PDR using the equivalent dose in 2-Gy fractions model, the median dose received by 100% and 90% of the target was 54.4 Gy(alpha/beta10) and 63.5 Gy(alpha/beta10) for the intermediate-risk clinical target volume and 61.6 Gy(alpha/beta10) and 74.9 Gy(alpha/beta10) for the high-risk clinical target volume, respectively. Of the 45 patients, 23 and 2 developed acute Grade 1-2 and Grade 3 complications, respectively; 21 patients presented with delayed Grade 1-2 complications. One other patient presented with Grade 3 vesicovaginal fistula. No Grade 4 or greater complications, whether acute or delayed, were observed. CONCLUSION Magnetic resonance imaging-guided PDR brachytherapy with optimization integrating the limits of tolerance to critical organs allows for excellent local control rates. Moreover, the present results have confirmed that the ability to optimize dwell times can contribute to an improvement in local control rates with a low level of late side effects.

Involved-node radiotherapy and modern radiation treatment techniques in patients with Hodgkin lymphoma.

PURPOSE To assess the clinical outcome of the involved-node radiotherapy (INRT) concept using modern radiation treatments (intensity-modulated radiotherapy [IMRT] or deep-inspiration breath-hold radiotherapy [DIBH) in patients with localized supradiaphragmatic Hodgkin lymphoma. METHODS AND MATERIALS All but 2 patients had early-stage Hodgkin lymphoma, and they were treated with chemotherapy prior to irradiation. Radiation treatments were delivered using the INRT concept according to European Organization for Research and Treatment of Cancer guidelines. IMRT was performed with the patient free-breathing. For the adapted breath-hold technique, a spirometer dedicated to DIBH radiotherapy was used. Three-dimensional conformal radiotherapy was performed with those patients. RESULTS Fifty patients with Hodgkin lymphoma (48 patients with primary Hodgkin lymphoma, 1 patient with recurrent disease, and 1 patient with refractory disease) entered the study from January 2003 to August 2008. Thirty-two patients were treated with IMRT, and 18 patients were treated with the DIBH technique. The median age was 28 years (range, 17-62 years). Thirty-four (68%) patients had stage I - (I-IIA) IIA disease, and 16 (32%) patients had stage I - (I-IIB) IIB disease. All but 3 patients received three to six cycles of adriamycin, bleomycin, vinblastine, and dacarbazine (ABVD). The median radiation doses to patients treated with IMRT and DIBH were, respectively, 40 Gy (range, 21.6-40 Gy) and 30.6 Gy (range, 19.8-40 Gy). Protection of various organs at risk was satisfactory. Median follow-up was 53.4 months (range, 19.1-93 months). The 5-year progression-free and overall survival rates for the whole population were 92% (95% confidence interval [CI], 80%-97%) and 94% (95% CI, 75%-98%), respectively. Recurrences occurred in 4 patients: 2 patients had in-field relapses, and 2 patients had visceral recurrences. Grade 3 acute lung toxicity (transient pneumonitis) occurred in 1 case. CONCLUSIONS Our results suggest that patients with localized Hodgkin lymphoma can be safely and efficiently treated using the INRT concept and modern radiation treatment techniques such as IMRT and DIBH.

Technical aspects and perspectives of the vaginal mold applicator for brachytherapy of gynecologic malignancies

PURPOSE The importance of the quality of cervical cancer brachytherapy applicators has been reported, suggesting a direct influence of competent technical implant performance on outcome. In our institute, an original brachytherapy technique based on the use of a molded applicator for genital tract brachytherapy has been applied routinely in clinical practice. Here, we report the technical aspects of this customized applicator and perspectives on its use. TECHNICAL ASPECTS The first step consists of a vaginal impression that accurately shows the topography and extension of the tumor as well as the anatomy of the vagina and cervix. From this impression, an acrylic applicator is made. Then, the intended positions of the vaginal catheters are drawn on the surface of the mold by the radiation oncologist. Two plastic vaginal catheters are introduced and fixed on the internal surface of the molded applicator. A hole for the cervical os is made through which the uterine probe will be positioned. PERSPECTIVES This method allows for high specificity within the framework of a modern brachytherapy procedure, integrating the tumor topography, anatomy of the patient, and internal movements of target and critical volumes. This technique has been successfully extended to other tumor locations, such as genital tract rhabdomyosarcoma in children and postoperative endocavitary brachytherapy in patients with endometrial cancer. CONCLUSION Customization of a vaginal brachytherapy applicator allows for the maintenance of morphologic optimization throughout the treatment course, which better takes into account a fourth dimension: internal organ motion during the course of brachytherapy.

Nomogram to predict rectal toxicity following prostate cancer radiotherapy

Background To identify predictors of acute and late rectal toxicity following prostate cancer radiotherapy (RT), while integrating the potential impact of RT technique, dose escalation, and moderate hypofractionation, thus enabling us to generate a nomogram for individual prediction. Methods In total, 972 patients underwent RT for localized prostate cancer, to a total dose of 70 Gy or 80 Gy, using two different fractionations (2 Gy or 2.5 Gy/day), by means of several RT techniques (3D conformal RT [3DCRT], intensity-modulated RT [IMRT], or image-guided RT [IGRT]). Multivariate analyses were performed to identify predictors of acute and late rectal toxicity. A nomogram was generated based on the logistic regression model used to predict the 3-year rectal toxicity risk, with its accuracy assessed by dividing the cohort into training and validation subgroups. Results Mean follow-up for the entire cohort was 62 months, ranging from 6 to 235. The rate of acute Grade ≥2 rectal toxicity was 22.2%, decreasing when combining IMRT and IGRT, compared to 3DCRT (RR = 0.4, 95%CI: 0.3–0.6, p<0.01). The 5-year Grade ≥2 risks for rectal bleeding, urgency/tenesmus, diarrhea, and fecal incontinence were 9.9%, 4.5%, 2.8%, and 0.4%, respectively. The 3-year Grade ≥2 risk for overall rectal toxicity increased with total dose (p<0.01, RR = 1.1, 95%CI: 1.0–1.1) and dose per fraction (2Gy vs. 2.5Gy) (p = 0.03, RR = 3.3, 95%CI: 1.1–10.0), and decreased when combining IMRT and IGRT (RR = 0.50, 95% CI: 0.3–0.8, p<0.01). Based on these three parameters, a nomogram was generated. Conclusions Dose escalation and moderate hypofractionation increase late rectal toxicity. IMRT combined with IGRT markedly decreases acute and late rectal toxicity. Performing combined IMRT and IGRT can thus be envisaged for dose escalation and moderate hypofractionation. Our nomogram predicts the 3-year rectal toxicity risk by integrating total dose, fraction dose, and RT technique.