Kimmen Quan

Salvage stereotactic radiosurgery for recurrent glioblastoma multiforme with prior radiation therapy

BACKGROUND Glioblastoma multiforme (GBM) carries a poor prognosis with high recurrence rates. Salvage stereotactic radiosurgery (SRS) may be an effective treatment option. METHODS We retrospectively reviewed 34 patients (41 lesions) treated with salvage SRS for recurrent GBM between 2004 and 2012. Initial surgical treatments were gross total resection (58%), subtotal resection (STR) (24%), and biopsy (18%). All patients were treated with prior radiation therapy. Recurrent disease was treated with salvage SRS with a median dose and fractions of 23.4 Gy (range, 12-30) and 3 (range, 1-3), respectively. Cox proportional hazards regression was conducted to establish predictive factors (P ≤ 0.05) Results: Median follow-up from salvage SRS was 10.8 months (interquartile range [IQR], 7.0-15.6). The median time from initial radiation therapy to salvage SRS was 13.7 months (IQR, 2.9-25.0). The 6- and 12-month overall survival from salvage SRS were 84.9% and 42.5%, respectively. On univariate analysis, STR was associated with inferior survival from salvage SRS (P ≤ 0.05). The 6- and 12-month local control (LC) estimates were 63.1% and 16.4%, respectively. On univariate analysis, higher biological effective dose and prior temozolomide were associated with superior LC. Concerning toxicity, there were 4 (12%) grade 2 and 1 (3%) grade 3 adverse events within this patient series. No grade 4 or grade 5 toxicities were observed. CONCLUSION Our outcomes suggest that SRS is a feasible treatment option with acceptable salvage survival rates, given the poor prognosis of this disease.

Toxicities Following Stereotactic Ablative Radiotherapy Treatment of Locally-Recurrent and Previously Irradiated Head and Neck Squamous Cell Carcinoma☆

Stereotactic ablative radiotherapy (SABR) with concomitant cetuximab is an effective treatment option for previously irradiated, locally recurrent squamous cell carcinoma of the head and neck. Its local control and overall survival are similar to those of other available treatment options. Each retreatment depends heavily on the prior treatment and every patient is a special case. Based on the experience of our institution and previously published studies, for patients who receive concomitant cetuximab with a median prior radiation therapy dose of 70Gy, we recommend a total dose of 40-44Gy delivered in 5 fractions on alternating days over 1-2 weeks. However, Grade 2 or 3 toxicities are not uncommon. Therefore, in this review, we also report a pilot study that applies a normal tissue complication probability dose-response model to estimate the probability of toxicities in locally recurrent squamous cell carcinoma of the head and neck reirradiated with SABR. Although this dose-response model includes concurrent targeted therapy and no comparable model yet exists for SABR without it, complication rates without concurrent biological therapy or chemotherapy should be no higher than those described here.

Stereotactic ablative radiosurgery for locally advanced or recurrent skull base malignancies with prior external beam radiation therapy.

Purpose: Stereotactic ablative radiotherapy (SABR) is an attractive modality to treat malignancies invading the skull base as it can deliver a highly conformal dose with minimal toxicity. However, variation exists in the prescribed dose and fractionation. The purpose of our study is to examine the local control, survival, and toxicities in SABR for the treatment of previously irradiated malignant skull base tumors. Materials and methods: A total of 31 patients and 40 locally advanced or recurrent head and neck malignancies involving the skull base treated with a common SABR regimen, which delivers a radiation dose of 44 Gy in 5 fractions from January 1st, 2004 to December 31st, 2013, were retrospectively reviewed. The local control rate (LC), progression-free survival rate, overall survival (OS) rate, and toxicities were reported. Results: The median follow-up time of all patients was 11.4 months (range: 0.6–67.2 months). The median tumor volume was 27 cm3 (range: 2.4–205 cm3). All patients received prior external beam radiation therapy with a median radiation dose of 64 Gy (range: 24–75.6 Gy) delivered in 12–42 fractions. Twenty patients had surgeries prior to SABR. Nineteen patients received chemotherapy. Specifically, eight patients received concurrent cetuximab (Erbitux™) with SABR. The median time-to-progression (TTP) was 3.3 months (range: 0–16.9 months). For the 29 patients (93.5%) who died, the median time from the end of first SABR to death was 10.3 months (range: 0.5–41.4 months). The estimated 1-year OS rate was 35%. The estimated 2-year OS rate was 12%. Treatment was well-tolerated without grade 4 or 5 treatment-related toxicities. Conclusion: Stereotactic ablative radiotherapy has been shown to achieve low toxicities in locally advanced or recurrent, previously irradiated head and neck malignancies invading the skull base.

One- vs. Three-Fraction Pancreatic Stereotactic Body Radiation Therapy for Pancreatic Carcinoma: Single Institution Retrospective Review

Background/introduction Early reports of stereotactic body radiation therapy (SBRT) for pancreatic ductal adenocarcinoma (PDAC) used single fraction, but eventually shifted to multifraction regimens. We conducted a single institution review of our patients treated with single- or multifraction SBRT to determine whether any outcome differences existed. Methods and materials Patients treated with SBRT in any setting for PDAC at our facility were included, from 2004 to 2014. Overall survival (OS), local control (LC), regional control (RC), distant metastasis (DM), and late grade 3 or greater radiation toxicities from the time of SBRT were calculated using Kaplan–Meier estimation to either the date of last follow-up/death or local/regional/distant failure. Results We identified 289 patients (291 lesions) with pathologically confirmed PDAC. Median age was 69 (range, 33–90) years. Median gross tumor volume was 12.3 (8.6–21.3) cm3 and planning target volume 17.9 (12–27) cm3. Single fraction was used in 90 (30.9%) and multifraction in 201 (69.1%) lesions. At a median follow-up of 17.3 months (IQR 10.1–29.3 months), the median survival for the entire cohort 17.8 months with a 2-year OS of 35.3%. Univariate analysis showed multifraction schemes to have a higher 2-year OS 30.5% vs. 37.5% (p = 0.019), it did not hold significance on MVA. Multifractionation schemes were found to have a higher LC on MVA (HR = 0.53, 95% CI, 0.33–0.85, p = 0.009). At 2 years, late grade 3+ toxicity was 2.5%. Post-SBRT CA19-9 was found on MVA to be a prognostic factor for OS (HR = 1.01, 95% CI, 1.01–1.01, p = 0.009), RC (HR = 1.01, 95% CI 1.01–1.01, p = 0.02), and DM (HR = 1.01, 95% CI, 1.01–1.01, p = 0.001). Conclusion Our single institution retrospective review is the largest to date comparing single and multifraction SBRT and the first to show multifraction regimen SBRT to have a higher LC than single fractionation. Additionally, we show low rates of severe late toxicity with SBRT.

Treatment Plan Technique and Quality for Single-Isocenter Stereotactic Ablative Radiotherapy of Multiple Lung Lesions with Volumetric-Modulated Arc Therapy or Intensity-Modulated Radiosurgery.

The aim of this study is to provide a practical approach to the planning technique and evaluation of plan quality for the multi-lesion, single-isocenter stereotactic ablative radiotherapy (SABR) of the lung. Eleven patients with two or more lung lesions underwent single-isocenter volumetric-modulated arc therapy (VMAT) radiosurgery or IMRS. All plans were normalized to the target maximum dose. For each plan, all targets were treated to the same dose. Plan conformity and dose gradient were maximized with dose-control tuning structures surrounding targets. For comparison, multi-isocenter plans were retrospectively created for four patients. Conformity index (CI), homogeneity index (HI), gradient index (GI), and gradient distance (GD) were calculated for each plan. V5, V10, and V20 of the lung and organs at risk (OARs) were collected. Treatment time and total monitor units (MUs) were also recorded. One patient had four lesions and the remainder had two lesions. Six patients received VMAT and five patients received intensity-modulated radiosurgery (IMRS). For those treated with VMAT, two patients received 3-arc VMAT and four received 2-arc VMAT. For those treated with IMRS, two patients were treated with 10 and 11 beams, respectively, and the rest received 12 beams. Prescription doses ranged from 30 to 54 Gy in three to five fractions. The median prescribed isodose line was 84% (range: 80–86%). The median maximum dose was 57.1 Gy (range: 35.7–65.1 Gy). The mean combined PTV was 49.57 cm3 (range: 14.90–87.38 cm3). For single-isocenter plans, the median CI was 1.15 (range: 0.97–1.53). The median HI was 1.19 (range: 1.16–1.28). The median GI was 4.60 (range: 4.16–7.37). The median maximum radiation dose (Dmax) to total lung was 55.6 Gy (range: 35.7–62.0 Gy). The median mean radiation dose to the lung (Dmean) was 4.2 Gy (range: 1.1–9.3 Gy). The median lung V5 was 18.7% (range: 3.8–41.3%). There was no significant difference in CI, HI, GI, GD, V5, V10, and V20 (lung, heart, trachea, esophagus, and spinal cord) between single-isocenter and multi-isocenter plans. This multi-lesion, single-isocenter lung SABR planning technique demonstrated excellent plan quality and clinical efficiency and is recommended for radiosurgical treatment of two or more lung targets for well-suited patients.

Results of a prospective phase 2 clinical trial of induction gemcitabine/capecitabine followed by stereotactic ablative radiation therapy in borderline resectable or locally advanced pancreatic adenocarcinoma

PURPOSE Stereotactic ablative radiation therapys (SABRs) great conformity and short duration has become an attractive treatment modality. We report a phase 2 clinical trial to evaluate efficacy and safety of induction chemotherapy (ICT) followed by SABR in patient with borderline resectable (BR) and locally advanced (LA) pancreatic ductal adenocarcinoma (PDAC). METHODS AND MATERIALS Patients with biopsy-proven BR or LA PDAC were treated with four 21-day cycles of intravenous gemcitabine and oral capecitabine. Patients were restaged within 4 weeks after ICT by computed tomography and treated by 3-fraction SABR if no metastasis or progressive disease was identified. Patients were restaged 4 weeks following SABR to determine resectability. Tumor response was assessed with carbohydrate antigen 19-9. RESULTS Thirty-five patients (19 BR/16 LA) were enrolled. The median age was 71.8 years (range, 50.6-81.1). ICT was completed in 91.4% (n = 32) of patients. All patients who completed ICT completed SABR. Of those 32 patients, 34.3% (n = 12: 10 BR, 2 LA) underwent pancreaticoduodenectomy and 11 of 12 (91.7%) received R0 resection. Median overall survival was 18.8, 28.3, and 14.3 months for the entire cohort, BR, and LA, respectively. The 2-year local progression-free survival (LPFS) was 44.9%, 40%, and 52% for the entire cohort, BR, and LA, respectively. For BR patients, multivariate analysis showed surgery was associated with better overall survival and LPFS. One-year LPFS for patients with surgery was 80% and 44% without surgery. Within the 15.4-month follow-up, no grade 3+ toxicity from SABR was observed. No significant quality of life change was observed before and after ICT, SABR, or surgery for BR or LA patients. CONCLUSIONS This is the first prospective phase 2 study to investigate the feasibility and efficacy of a 12-week gemcitabine/capecitabine ICT followed by SABR for BR or LA PDAC. The results suggest excellent tolerability, high R0 resection rates, and acceptable posttreatment complications.