Less Than Whole Uterus Irradiation for Locally Advanced Cervical Cancer Maintains Locoregional Control and Decreases Radiation Dose to Bowel.

This study aimed to evaluate whether our institutional standard of less-than-whole-uterus irradiation affects locoregional control in patients with locally advanced cervical cancer. We retrospectively reviewed 53 patients with stage IB to IVB cervical carcinoma who were treated with image guided intensity modulated radiation therapy and brachytherapy. The entire uterus was not included in the clinical target volume, as per our institutional standard. Dosimetric parameters were obtained, including positron emission tomography gross tumor volume (GTV), uterus volume excluding GTV, proportion of uterus included in the planning target volume (PTV; percentage), volume of overlap between uterus and prescription dose (cm3), minimum and mean dose to the uterus, and bowel V40 and D200cc. Local, regional, and distant failure and death were recorded. The median proportion of the uterus included in the PTV was 66%. With a median follow-up of 44 months, no patient experienced isolated local recurrence, and 2-year locoregional failure was 10.9%. Positron emission tomography GTV correlated significantly with increased chance of any failure (P = .049; 95% confidence interval, 1.000-1.018). Compared with patients who had ≥90% of the uterus included in the PTV (n = 12), patients who had <90% (n = 41) of the uterus included in the PTV had significantly lower bowel V40 (P = .049) and D200cc (P = .006). Less-than-whole-uterus irradiation for locally advanced cervical cancer does not compromise locoregional control and reduces bowel V40 and D200cc. Further investigation is required to evaluate whether this reduction in bowel dose translates to a clinically significant reduction in bowel toxicity and whether modifications should be made to the recommended definitive cervix intensity modulated radiation therapy volumes.

Kozak MM ，Koenig JL ，von Eyben R ，Kidd EA ... -  《-》

Less than whole uterus irradiation for patients with locally advanced cervical cancer.

Current consensus guidelines for definitive cervical cancer intensity modulated radiation therapy (IMRT) recommend inclusion of the entire uterus within the clinical target volume, however this is debated. We aimed to evaluate outcomes of patients with cervical cancer who were treated with less than whole uterus irradiation. We identified 109 patients with FIGO Stage IB-IVA cervical cancer treated definitively with concurrent chemoradiation, including IMRT and brachytherapy, from 2010 to 2022 at a single institution where the practice was to include the gross cervix tumor with an internal target volume with differences in bladder filing accounted for, plus additional 5 mm planning target volume (PTV) margin. Local, regional, and distant recurrences were analyzed using competing risk methods, and a Wilcoxon rank sum test was performed to assess differences in dose to organs at risk based on the proportion of the uterus included in the PTV, with the median proportion of the uterus included (75 %) used as the cut-point. The median follow-up time was 65 months (range 3-352 months). The 2-year cumulative incidence of LR for the entire cohort was 4.2 % (95 % confidence interval [CI] 1.3-9.7). Compared with patients who had ≥ 75 % of the uterus included in the PTV, patients who had < 75 % of the uterus included in the PTV had significantly lower bowel D200cc (p = 0.02). The cumulative incidence of local failure (LR) was not significantly different between the two groups. Including less than the whole uterus for definitive cervix cancer IMRT does not seem to compromise local control. Less than whole uterus irradiation could be considered for carefully selected cervix cancer patients to decrease bowel dose and possible treatment-related toxicity.

Hui C ，Ewongwo A ，Mendoza MG ，Kozak MM ，Jackson S ，Fu J ，Kidd E ... -  《-》

Is SBRT Boost Feasible for PET Positive Lymph Nodes for Cervical Cancer? Evaluation using Tumor Control Probability and QUANTEC Criteria.

This study aimed to examine the feasibility of stereotactic body radiation therapy (SBRT) as an external beam radiation therapy boost to positron emission tomography (PET) positive lymph nodes (LN) in patients with cervical cancer and to evaluate overall tumor control probability (TCP) increase. Ten patients with cervical cancer and PET positive LN metastasis who received external beam radiation therapy (45 Gy), followed by a 3-dimensional conformal radiation therapy boost (5.4-9 Gy) and tandem-and-ovoid high-dose-rate brachytherapy (16-30 Gy) were retrospectively enrolled in this study. SBRT plans were generated using 21 Gy, 24 Gy, or 30 Gy as a replacement for 3-dimensional conformal radiation therapy boost. The 2 Gy-per-fraction equivalent dose maps were made using an α/β value of 10 for PET positive LNs and 3 for organs at risk (OARs). TCP values were calculated using a logistic TCP model, where 2 input parameters (D50 and Gamma50 = 2) were modeled by 2 clinical outcomes: our institution and the literature. OAR sparing was evaluated using Quantitative Analyses of Normal Tissue Effects in the Clinic (QUANTEC) dose limits. Thirty percent of 10 patients receiving conventional boost experienced recurrence. The TCP of the SBRT schemes was 88% ± 7% (97% ± 2%; 21 Gy), 96% ± 1% (99% ± 0%; 24 Gy), and 99% ± 1% (100% ± 0%; 30 Gy), and the conventional LN-boost TCP value was 25% ± 11% (58% ± 15%) when TCP input parameters were based on published clinical outcome data for LN SBRT treatments (institutional outcome data). The tumor coverage doses (D90) of the SBRT boost plans were on average 32.34 Gyαβ=10 (21 Gy), 37.78 Gyαβ=10 (24 Gy), and 55.54Gyαβ=10 (30 Gy) higher than the conventional LN boost plan. The QUANTEC OAR dose constraints were met for the bladder, rectum, and bowel in all cases for the SBRT LN 21 Gy group, and in 90% and 70% of cases in the SBRT LN 24 Gy and SBRT LN 30 Gy groups, respectively. An SBRT boost dose of 30 Gy can be delivered without compromising QUANTEC OAR limits. The use of SBRT increases TCP values, regardless of the input parameters.

Snyder JE ，Willett AB ，Sun W ，Kim Y ... -  《-》

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 ... -  《-》

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.

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. 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. 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). 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.

Dyk P ，Jiang N ，Sun B ，DeWees TA ，Fowler KJ ，Narra V ，Garcia-Ramirez JL ，Schwarz JK ，Grigsby PW ... -  《-》