Impact of Reirradiation Utilizing Fractionated Stereotactic Radiotherapy for Recurrent Glioblastoma.

BACKGROUND: Patients with recurrent glioblastoma (GBM) have limited treatment options. This study determined whether patients with recurrent GBM treated with initial radiation/temozolomide (TMZ) and reirradiation using fractionated stereotactic radiotherapy (FSRT) had improved outcomes. MATERIALS AND METHODS: We identified 95 patients with recurrent GBM, 50 of whom underwent FSRT at recurrence and 45 who had systemic treatment only (control). The median total FSRT dose at the time of GBM recurrence was 30 Gy in five fractions of the gadolinium-enhanced tumor only. RESULTS: With a median follow-up of 18 months, the progression-free survival (PFS) and overall survival (OS) following initial GBM diagnosis were longer in the reirradiation group compared to the control group (13.5 vs. 7.5 months [p=0.001] and 24.6 vs. 12.6 months [p<0.001], respectively). For patients who underwent reirradiation, the median time interval between the end of the initial radiation and reirradiation was 15.2 months. The median OS after GBM recurrence was longer in the reirradiation group versus the control group (9.9 vs. 3.5 months [p<0.001]), with a one-year OS survival rate of 22%. The hazard ratio for death of patients in the reirradiation group was 0.31 [0.19-0.50]. The reirradiation group had a higher percentage of patients who received bevacizumab (BEV, 62.0% vs. 28.9%, p=0.002) and a lower percentage of patients whose TMZ was discontinued due to toxicity (8.0% vs. 28.9%, p=0.017) compared to the control group. CONCLUSIONS: Reirradiation utilizing FSRT was associated with improved PFS and OS after GBM recurrence compared to the control group who did not receive additional irradiation.

Efficacy of laser interstitial thermal therapy for biopsy-proven radiation necrosis in radiographically recurrent brain metastases.

Background: Laser interstitial thermal therapy (LITT) in the setting of post-SRS radiation necrosis (RN) for patients with brain metastases has growing evidence for efficacy. However, questions remain regarding hospitalization, local control, symptom control, and concurrent use of therapies. Methods: Demographics, intraprocedural data, safety, Karnofsky performance status (KPS), and survival data were prospectively collected and then analyzed on patients who consented between 2016-2020 and who were undergoing LITT for biopsy-proven RN at one of 14 US centers. Data were monitored for accuracy. Statistical analysis included individual variable summaries, multivariable Fine and Gray analysis, and Kaplan-Meier estimated survival. Results: Ninety patients met the inclusion criteria. Four patients underwent 2 ablations on the same day. Median hospitalization time was 32.5 hours. The median time to corticosteroid cessation after LITT was 13.0 days (0.0, 1229.0) and cumulative incidence of lesional progression was 19% at 1 year. Median post-procedure overall survival was 2.55 years [1.66, infinity] and 77.1% at one year as estimated by KaplanMeier. Median KPS remained at 80 through 2-year follow-up. Seizure prevalence was 12% within 1-month post-LITT and 7.9% at 3 months; down from 34.4% within 60-day prior to procedure. Conclusions: LITT for RN was not only again found to be safe with low patient morbidity but was also a highly effective treatment for RN for both local control and symptom management (including seizures). In addition to averting expected neurological death, LITT facilitates ongoing systemic therapy (in particular immunotherapy) by enabling the rapid cessation of steroids, thereby facilitating maximal possible survival for these patients.

Technical Note: Comparison of the internal target volume (ITV) contours and dose calculations on 4DCT, average CBCT, and 4DCBCT imaging for lung stereotactic body radiation therapy (SBRT).

PURPOSE: To investigate the differences between internal target volumes (ITVs) contoured on the simulation 4DCT and daily 4DCBCT images for lung cancer patients treated with stereotactic body radiotherapy (SBRT) and determine the dose delivered on 4D planning technique. METHODS: For nine patients, 4DCBCTs were acquired before each fraction to assess tumor motion. An ITV was contoured on each phase of the 4DCBCT and a union of the 10 ITVs was used to create a composite ITV. Another ITV was drawn on the average 3DCBCT (avgCBCT) to compare with current clinical practice. The Dice coefficient, Hausdorff distance, and center of mass (COM) were averaged over four fractions to compare the ITVs contoured on the 4DCT, avgCBCT, and 4DCBCT for each patient. Planning was done on the average CT, and using the online registration, plans were calculated on each phase of the 4DCBCT and on the avgCBCT. Plan dose calculations were tested by measuring ion chamber dose in the CIRS lung phantom. RESULTS: The Dice coefficients were similar for all three comparisons: avgCBCT-to-4DCBCT (0.7 ± 0.1), 4DCT-to-avgCBCT (0.7 ± 0.1), and 4DCT-to-4DCBCT (0.7 ± 0.1); while the mean COM differences were also comparable (2.6 ± 2.2mm, 2.3 ± 1.4mm, and 3.1 ± 1.1mm, respectively). The Hausdorff distances for the comparisons with 4DCBCT (8.2 ± 2.9mm and 8.1 ± 3.2mm) were larger than the comparison without (6.5 ± 2.5mm). The differences in ITV D95% between the treatment plan and avgCBCT calculations were 4.3 ± 3.0% and -0.5 ± 4.6%, between treatment plan and 4DCBCT plans, respectively, while the ITV V100% coverages were 99.0 ± 1.9% and 93.1 ± 8.0% for avgCBCT and 4DCBCT, respectively. CONCLUSION: There is great potential for 4DCBCT to evaluate the extent of tumor motion before treatment, but image quality challenges the clinician to consistently delineate lung target volumes.

Outcomes of carotid-sparing IMRT for T1 glottic cancer: Comparison with conventional radiation.

OBJECTIVES: We aim to report oncologic outcomes after conventional radiotherapy (ConRT) using opposed lateral beams and intensity-modulated radiation therapy (IMRT) for tumor (T)1 nodal (N)0 T1 N0 glottic squamous cell carcinoma. STUDY DESIGN: Retrospective case-control study. METHODS: We retrospectively reviewed demographic, disease, and treatment characteristics for patients treated at our institution during 2000 to 2013. RESULTS: One hundred fifty-three patients (71%) were treated using ConRT and 62 (29%) using IMRT. The median follow-up for all patients was 68 months. There was no statistically significant difference in 5-year local control between patients with T1a versus T1b disease (94% vs. 89%, respectively, P = 0.5). Three-year locoregional control for patients treated with ConRT was 94% compared to 97% with IMRT (P = 0.4). Three-year overall survival (OS) for patients treated with ConRT was 92.5% compared with 100% with IMRT (P = 0.1). Twelve of 14 patients with local recurrence underwent salvage surgery with 5-year ultimate locoregional control of 98.5% and 97.1% in the ConRT and IMRT cohorts, respectively (P = 0.7). Multivariate analysis showed age < 60 years (P < 0.0001) and pretreatment Eastern Cooperative Oncology Group performance status <2 (P = 0.0022) to be independent correlates of improved OS. Postradiation cerebrovascular events were in four patients in the ConRT cohort (3%), whereas no patients in the IMRT cohort suffered any events. CONCLUSION: Because the oncologic outcomes for patients treated with IMRT were excellent and IMRT allows for carotid sparing, we have transitioned to IMRT as our standard for most patients with T1 glottic cancer. LEVEL OF EVIDENCE: 3b Laryngoscope, 130:146-153, 2020.

Geometric and dosimetric impact of anatomical changes for MR-only radiation therapy for the prostate.

PURPOSE: With the move towards magnetic resonance imaging (MRI) as a primary treatment planning modality option for men with prostate cancer, it becomes critical to quantify the potential uncertainties introduced for MR-only planning. This work characterized geometric and dosimetric intra-fractional changes between the prostate, seminal vesicles (SVs), and organs at risk (OARs) in response to bladder filling conditions. MATERIALS AND METHODS: T2-weighted and mDixon sequences (3-4 time points/subject, at 1, 1.5 and 3.0 T with totally 34 evaluable time points) were acquired in nine subjects using a fixed bladder filling protocol (bladder void, 20 oz water consumed pre-imaging, 10 oz mid-session). Using mDixon images, Magnetic Resonance for Calculating Attenuation (MR-CAT) synthetic computed tomography (CT) images were generated by classifying voxels as muscle, adipose, spongy, and compact bone and by assignment of bulk Hounsfield Unit values. Organs including the prostate, SVs, bladder, and rectum were delineated on the T2 images at each time point by one physician. The displacement of the prostate and SVs was assessed based on the shift of the center of mass of the delineated organs from the reference state (fullest bladder). Changes in dose plans at different bladder states were assessed based on volumetric modulated arc radiotherapy (VMAT) plans generated for the reference state. RESULTS: Bladder volume reduction of 70 ± 14% from the final to initial time point (relative to the final volume) was observed in the subject population. In the empty bladder condition, the dose delivered to 95% of the planning target volume (PTV) (D95%) reduced significantly for all cases (11.53 ± 6.00%) likely due to anterior shifts of prostate/SVs relative to full bladder conditions. D15% to the bladder increased consistently in all subjects (42.27 ± 40.52%). Changes in D15% to the rectum were patient-specific, ranging from -23.93% to 22.28% (-0.76 ± 15.30%). CONCLUSIONS: Variations in the bladder and rectal volume can significantly dislocate the prostate and OARs, which can negatively impact the dose delivered to these organs. This warrants proper preparation of patients during treatment and imaging sessions, especially when imaging required longer scan times such as MR protocols.

Adjuvant External Radiation Impacts Outcome of Pelvis-limited Stage III Endometrial Carcinoma: A Multi-institutional Study.

BACKGROUND: Adjuvant therapy choice for women with FIGO stage III endometrial carcinoma (EC) is controversial. We investigate the comparative benefit of adjuvant chemotherapy (CT) alone, radiation therapy alone (RT) or in combination (chemotherapy and radiation therapy [CRT]) with respect to recurrence-free survival (RFS) and overall survival (OS) in women with pelvis-limited (PL) EC (stage IIIA, IIIB, and IIIC1). MATERIALS AND METHODS: A multi-institutional database of 270 surgically staged women with PLEC was analyzed. Univariate log-rank analyses and Cox regression multivariate analyses (MVA) were performed to identify factors associated with RFS and OS. RESULTS: Median RFS and OS were 112 and 130 months, respectively, for the full cohort. Adjuvant treatment was CT in 21%, RT in 27%, and CRT in 47%. Age, year of treatment, grade, histology, and adjuvant treatment were significantly associated with RFS and OS on univariate analysis. PLEC patients receiving CT alone fared worse in terms of RFS (P=0.07 relative to RT and <0.01 relative to CRT). On MVA, CRT retained significantly improved RFS relative to CT (hazard ratio for recurrence 0.38, P<0.01). PLEC patients receiving RT or CRT had improved OS compared with CT, P<0.01 and 0.03, respectively. On MVA, both RT only and CRT retained association with improved OS relative to CT alone (hazard ratio for death, 0.43, P=0.02 and 0.40, P<0.01, respectively). CONCLUSIONS: For surgically staged PL stage III EC, treatment regimens incorporating RT were associated with improved survival endpoints relative to CT alone. As such, RT should be considered an important component in the adjuvant management of stage III PLEC.

The Impact of Adjuvant Therapy on Survival and Recurrence Patterns in Women With Early-Stage Uterine Carcinosarcoma: A Multi-institutional Study.

OBJECTIVE: The aim of the study was to characterize the impact of adjuvant therapy on survival in women with stage I/II uterine carcinosarcoma after primary surgery. METHODS: We reviewed records of 118 consecutively treated women with 2009 International Federation of Gynecology and Obstetrics stage I/II uterine carcinosarcoma who underwent hysterectomy between 1990 and 2014 at 4 academic institutions. Patients were categorized by adjuvant treatment group into observation, chemotherapy only, radiation only, and combined chemotherapy and radiation. Survival analyses were conducted using Kaplan-Meier and Cox proportional hazards models. RESULTS: Median follow-up was 28 months (range, 1-244 months). Lymphadenectomy was performed in 94 patients (80%). Postoperative management included observation (n = 37 [31%]), chemotherapy alone (n = 19 [16%]), radiation therapy (RT) alone (n = 24 [20%]), and combined RT and chemotherapy (n = 38 [32%]). Radiation therapy modality included vaginal brachytherapy in 22 patients, pelvic external beam RT in 21 patients, and combination in 19 patients. In 58% of women, chemotherapy consisted of carboplatin/paclitaxel. Median overall survival for all women was 97 months. On univariate analysis, adjuvant treatment group was associated with improved overall survival (hazard ratio [HR], 0.74; confidence interval [CI], 0.58-0.96; p = 0.02), freedom from vaginal recurrence (HR, 0.55; CI, 0.37-0.82]; p = 0.004), and freedom from any recurrence (HR, 0.70; CI, 0.54-0.92; p = 0.01). Pairwise comparisons demonstrated a significant benefit to chemoradiation over other adjuvant treatments. Adjuvant treatment group remained a significant covariate for all 3 end points on multivariate analysis as well. In addition, lymphadenectomy improved overall survival on multivariate analysis (HR, 0.24; CI, 0.09-0.61; p = 0.003). Of patients under observation only who had a recurrence, 8 (44%) of 18 had a recurrence in the vagina as the sole site of recurrence. By contrast, of women who received vaginal brachytherapy, significantly fewer had a recurrence in the vagina (1/42 [2.3%]; p < 0.003, log-rank test). CONCLUSIONS: In women with early-stage uterine carcinosarcoma, our data suggest superior survival end points with combined RT and chemotherapy. The frequency of vaginal recurrence suggests a role for incorporating vaginal brachytherapy in the adjuvant management of this disease.

Long-term outcomes after surgical or nonsurgical initial therapy for patients with T4 squamous cell carcinoma of the larynx: A 3-decade survey.

BACKGROUND: The current study was conducted to evaluate long-term disease control, survival, and functional outcomes after surgical and nonsurgical initial treatment for patients with T4 larynx cancer. METHODS: Demographics, disease stage, and treatment characteristics were reviewed for 221 sequential patients treated for T4 laryngeal squamous cell cancer at a single institution between 1983 and 2011. Survival and disease control outcomes were calculated. RESULTS: The median follow-up time was 47 months (71 months for patients still alive at the time of analysis). The overall 5-year and 10-year overall survival rates were 52% and 29%, respectively, and the corresponding disease-free survival rates were 57% and 48%, respectively. Overall 5-year and 10-year locoregional control rates were 78% and 67%, respectively, and the corresponding rates for freedom from distant metastasis were 76% and 74%, respectively. On both univariate and multivariate analyses, lymph node-positive disease at the time of presentation was associated with overall mortality (P<.0001). Patients treated with laryngectomy followed by postlaryngectomy radiotherapy (161 patients) achieved better initial locoregional control than patients treated with a laryngeal preservation (LP) approach (60 patients) throughout the follow-up period (log-rank P<.007) yet the median overall survival times were equal for both groups (64 months; 95% confidence interval 47-87 months and 38-87 months, respectively [P =.7]). Patients treated with an LP approach had a tracheostomy rate of 45% and an any-event aspiration rate of 23%. Rates of high-grade dysphagia at the time of last follow-up were worse for patients treated with an LP approach (P<.01). CONCLUSIONS: Surgery and postoperative radiotherapy can produce substantial long-term cancer control and survival rates for patients with T4 larynx cancer. Caution should be taken when selecting patients for initial nonsurgical treatment because of significant rates of functional impairment despite survival equivalence.

Estimation of daily interfractional larynx residual setup error after isocentric alignment for head and neck radiotherapy: quality assurance implications for target volume and organs-at-risk margination using daily CT on- rails imaging.

Larynx may alternatively serve as a target or organs at risk (OAR) in head and neck cancer (HNC) image-guided radiotherapy (IGRT). The objective of this study was to estimate IGRT parameters required for larynx positional error independent of isocentric alignment and suggest population-based compensatory margins. Ten HNC patients receiving radiotherapy (RT) with daily CT on-rails imaging were assessed. Seven landmark points were placed on each daily scan. Taking the most superior-anterior point of the C5 vertebra as a reference isocenter for each scan, residual displacement vectors to the other six points were calculated postisocentric alignment. Subsequently, using the first scan as a reference, the magnitude of vector differences for all six points for all scans over the course of treatment was calculated. Residual systematic and random error and the necessary compensatory CTV-to-PTV and OAR-to-PRV margins were calculated, using both observational cohort data and a bootstrap-resampled population estimator. The grand mean displacements for all anatomical points was 5.07 mm, with mean systematic error of 1.1 mm and mean random setup error of 2.63 mm, while bootstrapped POIs grand mean displacement was 5.09 mm, with mean systematic error of 1.23 mm and mean random setup error of 2.61 mm. Required margin for CTV-PTV expansion was 4.6 mm for all cohort points, while the bootstrap estimator of the equivalent margin was 4.9 mm. The calculated OAR-to-PRV expansion for the observed residual setup error was 2.7 mm and bootstrap estimated expansion of 2.9 mm. We conclude that the interfractional larynx setup error is a significant source of RT setup/delivery error in HNC, both when the larynx is considered as a CTV or OAR. We estimate the need for a uniform expansion of 5 mm to compensate for setup error if the larynx is a target, or 3 mm if the larynx is an OAR, when using a nonlaryngeal bony isocenter.