Assessment of radiation doses to the para-aortic, pelvic, and inguinal lymph nodes delivered by image-guided adaptive brachytherapy in locally advanced cervical cancer.

This study evaluated the dose delivered to lymph nodes (LNs) by brachytherapy (BT) and the effect of BT image-guided optimization on the LN dose. Twenty-five patients with locally advanced cervical cancer were retrospectively analyzed, 16 patients of them had LN involvement. The patients received whole pelvis intensity-modulated radiation therapy (45-50 Gy/25-30 fx) to whole pelvis and two fractions of MRI pulsed-dose-rate BT. The delineated LN groups were para-aortic, inguinal, common iliac (CI), external iliac, internal iliac, obturator, and presacral. For each LN group, D98%, D50%, and D2% (the dose that covers 98%, 50%, and 2% of the volume, respectively) were evaluated for optimized and standard BT plans. The correlation between total reference air kerma (TRAK) and D50% of the LN groups was evaluated. BT contributed considerable dose (mean D50% was 3.8-6.2 Gy equivalent total dose in 2-Gy fractions) to the pelvic LN (external iliac, internal iliac, obturator, and presacral) in optimized plans, whereas less-dose contribution to CI, para-aortic, and inguinal (mean D50% was 0.5-1.9 Gy equivalent total dose in 2-Gy fractions) was observed. Optimized plans delivered less dose to the LNs as compared with standard plans, although differences only amounted to a mean of 0.2-0.9 Gy (D50%). TRAK showed a significant correlation with LN D50% for all LN groups except CI, although only 19-38% of the dose variation could be explained by the TRAK. BT contributes considerable dose to pelvic LNs and should be considered in the evaluation of total LN doses.

Mohamed SM ，Aagaard T ，Fokdal LU ，Pedersen EM ，Lindegaard JC ，Tanderup K ... -  《-》

Contribution of image-guided adaptive brachytherapy to pelvic nodes treatment in locally advanced cervical cancer.

With the increasing use of simultaneous integrated boost in the treatment of cervical cancer, there is a need to anticipate the brachytherapy (BT) contribution at the level of the pathologic pelvic lymph nodes. This study aimed to report the dose delivered at their level during BT. Patients with pelvic nodal involvement and treated with a combination of chemoradiation followed by image-guided adaptive pulsed-dose-rate BT were selected. On per BT three-dimensional images, pelvic lymphadenopathies were delineated, without planning aim. For the purposes of the study, D100, D98, D90, and D50 were reviewed and converted in 2-Gy equivalent doses, using the linear quadratic model with an α/β of 10 Gy. Ninety-one patients were identified, allowing evaluation at the level of 226 lymphadenopathies. The majority of them were external iliac (48%), followed by common iliac (25%), and internal iliac (16%) regions. The 2-Gy equivalent doses D98 were 4.4 ± 1.9 Gy, 5.4 ± 3.1 Gy, and 4.3 ± 2.1 Gy for the obturator, internal iliac, and external iliac, respectively, and 2.8 ± 2.5 Gy for the common iliac. The contribution to the common iliac nodes was significantly lower than the one of external and internal iliac (p < 0.001). BT significantly contributes to the treatment of pelvic nodes at the level of approximately 5 Gy in the internal, external, and obturator areas and 2.5 Gy in the common iliac, allowing the anticipation of nodal boost with the simultaneous integrated boost technique. However, important individual variations have been observed, and evaluation of the genuine BT contribution should be recommended.

Bacorro W ，Dumas I ，Levy A ，Rivin Del Campo E ，Canova CH ，Felefly T ，Huertas A ，Marsolat F ，Haie-Meder C ，Chargari C ，Mazeron R ... -  《-》

Early clinical outcome of coverage probability based treatment planning for simultaneous integrated boost of nodes in locally advanced cervical cancer.

Lindegaard JC ，Assenholt M ，Ramlov A ，Fokdal LU ，Alber M ，Tanderup K ... -  《-》

The equivalent dose contribution from high-dose-rate brachytherapy to positive pelvic lymph nodes in locally advanced cervical cancer.

Definitive radiation therapy for locally advanced cervical cancer involves external beam radiation therapy (EBRT) and high-dose-rate (HDR) brachytherapy. There remains controversy and practice pattern variation regarding the optimal radiation dose to metastatic pelvic lymph nodes (LNs). This study investigates the contribution of the pelvic LN dose from HDR brachytherapy. For 17 patients with 36 positive pelvic LNs, each LN was contoured on a computed tomography (CT) plan for EBRT and on brachytherapy planning CTs using positron emission tomographic images obtained before chemoradiation. The mean delivered dose from each plan was recorded, and an equivalent dose in 2-Gy fractions (EQD2) was calculated. A Student's t test was performed to determine if the mean delivered dose is significantly different from the mean prescribed dose and EQD2. The average prescribed dose from the total EBRT was 54.09 Gy. The average prescribed HDR dose to International Commission on Radiation Units point A was 26.81 Gy. The average doses delivered to the involved LNs from EBRT and brachytherapy were 54.25 and 4.31 Gy, respectively, with the corresponding EQD2 of 53.45 and 4.00 Gy. There was no statistically significant difference (p < 0.05) between the mean delivered and the prescribed doses for EBRT and between the delivered dose and the EQD2 for EBRT and brachytherapy. Our study shows that the HDR contribution is 7% (4.00 Gy) of the total EQD2 (57.45 Gy). The HDR contribution should be accounted for when prescribing the EBRT boost dose to pelvic LNs for the optimal therapeutic dose.

Lee YC ，Rash DL ，Stern RL ，Mayadev JS ... -  《-》

Long term experience with 3D image guided brachytherapy and clinical outcome in cervical cancer patients.

To report our 10years' experience and learning curve of the treatment of cervical cancer patients with chemo radiotherapy and MRI (or CT in 9 selected patients) guided brachytherapy using pulsed dose rate (PDR) brachytherapy (BT). Hundred and seventy consecutive patients with cervical cancer FIGO stage IB-IVB (without metastases beyond the para-aortic nodal region) were treated in our institute between 2002 and 2012. Patients received external beam radiotherapy (nodal boost to the lymph nodes positive at diagnosis)±chemotherapy followed by a pulsed or low dose rate brachytherapy boost. MRI (or CT) images were taken with the applicator in situ. The first 16 patients were treated according to X-ray-based plans, optimized on MRI. High-risk CTV, intermediate-risk CTV, bladder, rectum and sigmoid were retrospectively contoured according to the GEC-ESTRO recommendations. In all other patients, treatment plans were optimized after delineation of the target volumes and organs at risk at MRI (or CT). Doses were converted to the equivalent dose in 2Gy (EQD2) by applying the linear quadratic model. The median age of the patients was 55years (range 16-88). 41% had stage III or IV disease. Of the 170 patients, 91 patients had on imaging metastatic lymph nodes at diagnosis (62 patients pelvic lymph node involvement and 29 para-aortic). In 27 (16%) patients the intracavitary technique was combined with interstitial brachytherapy. The mean D90 and D100 for the high-risk CTV were 84.8±8.36Gy and 67.5±6.29Gy for the entire patient group. Mean D90 and D100 values for the IR CTV were 68.7±5.5Gy and 56.5±6.25Gy. There was an important learning curve between both patient groups, with an increase in mean D90 of 75.8Gy for the first 16 patients compared to 85.8Gy for the second group. At the same time, the mean dose to 2cm3 of bladder and sigmoid decreased from 86.1Gy to 82.7Gy and from 70Gy to 61.7Gy, respectively. At a median follow-up of 37months (range 2-136months), local control rate for all patients was 96%, the regional control (pelvic and para-aortic) rate 81% and crude disease free survival rate 55%. The overall survival at 5years is 65%. The higher dose to the target volume resulted in an increase in local control from 88% in the first 16 patients compared to 97% in the second patient group. Regarding late toxicity, 21 patients (12%) presented grade 3-4 late morbidity. Rectal, urinary, sigmoid and vaginal morbidity was 5%, 6%, 2% and 5%, respectively. A correlation between rectal D2cm3 >65Gy and grade >3 late morbidity was found (p=0.006). Although the majority of the patients presented with locally advanced carcinoma, excellent local and regional control rates were achieved. Rectal, urinary, sigmoid and vaginal grade 3-4 morbidity was 5%, 6%, 2% and 5%, respectively. A correlation between rectal D2cm3 >65Gy and grade >3 late morbidity was found (p=0.006).

Ribeiro I ，Janssen H ，De Brabandere M ，Nulens A ，De Bal D ，Vergote I ，Van Limbergen E ... -  《-》