Stereotactic ablative radiotherapy for medically inoperable early stage lung cancer: early outcomes.

OBJECTIVE. To evaluate the clinical outcome and safety of stereotactic ablative radiotherapy for medically inoperable stage I non-small-cell lung carcinoma. DESIGN. Retrospective case series. SETTING. Pamela Youde Nethersole Eastern Hospital, Hong Kong. PATIENTS. All patients with medically inoperable stage I non-small-cell lung carcinoma receiving stereotactic ablative radiotherapy since its establishment in 2008. MAIN OUTCOME MEASURES. Disease control rate, overall survival, and treatment toxicities. RESULTS. Sixteen stage I non-small-cell lung carcinoma patients underwent the procedure from June 2008 to November 2011. The median patient age was 82 years and the majority (81%) had moderate-to-severe co-morbidity based on the Adult Comorbidity Evaluation 27 index. With a median follow-up of 22 months, the 2-year primary tumour control rate, disease-free survival and overall survival rates were 91%, 71% and 87%, respectively. No grade 3 (National Cancer Institute Common Terminology Criteria for Adverse Events) or higher treatment-related complications were reported. CONCLUSION. Stereotactic ablative radiotherapy can achieve a high degree of local control safely in medically inoperable patients with early lung cancer.

Potential improvement of tumor control probability by induction chemotherapy for advanced nasopharyngeal carcinoma.

PURPOSE: To assess the reduction of tumor bulk and improvement of tumor control probability (TCP) by using induction chemotherapy for advanced nasopharyngeal carcinoma (NPC). MATERIALS AND METHODS: From February to December 2005, 20 patients with Stage III-IVB NPC were treated with induction-concurrent chemotherapy and intensity-modulated radiotherapy with accelerated fractionation. Combination of cisplatin and 5-fluorouracil was used in the induction phase and single agent Cisplatin in the concurrent phase. All patients were irradiated at 2Gy per fraction, 6 daily fractions per week, to a total dose of 70Gy. RESULTS: Nineteen (95%) patients completed all 3 cycles of induction chemotherapy and 90% had 2 cycles of concurrent chemotherapy. Induction chemotherapy achieved significant down-staging of T-category in 35% of patients (p=0.016) and reduction of gross tumor volume (GTV_P) from 55.6 to 22.9cc (mean 61.4%, p<0.001). Although the mean radiation dose did not show any substantial change, the volume within GTV_P that failed to reach 70Gy was reduced from 10.2% to 3.8% (p=0.017). The estimated local TCP increased from 0.83 to 0.89 (p=0.002). CONCLUSIONS: Induction chemotherapy using cisplatin-5-fluorouracil could significantly reduce tumor bulk leading to potential improvement in tumor control.

The impact of dosimetric inadequacy on treatment outcome of nasopharyngeal carcinoma with IMRT.

BACKGROUND AND PURPOSE: This study aims to address the relationship between tumor size and dosimetric inadequacy in treating nasopharyngeal carcinoma (NPC), and how it subsequently affects the local control. MATERIAL AND METHODS: 444 NPC patients treated with IMRT from 2005 to 2010 were included in the study. The planning aim was to deliver at least 66.5 Gy (i.e. 95% of 70 Gy) to 95% of the primary gross tumor volume (GTV_P) while keeping all the critical neurological organs at risk (OAR) within dose tolerance. Treatment outcome were analyzed according to T stage, GTV_P volume and the degree of under-dosing. RESULTS: Disease outcome was related to T stage, GTV_P volume and the degree of under-dosing. The 5-year local failure free survival (LFFS), disease free survival (DFS) and overall survival (OS) for T4 disease were 74%, 50.4% and 63.6% respectively. 48 cm(3) was identified as the critical cut-off GTV_P volume, the large volume group (GTV_P ≥ 48 cm(3)) had lower 5-year DFS (50.4% vs. 76.6%) and OS (65.2% vs. 86.3%, p < 0.001). Most T4 diseases (and some T3) were under-dosed (<66.5 Gy) and an under-dosed GTV_P volume of 3.4 cm(3) was found to be prognostically important. Multivariate analyses showed that the effect of GTV_P volume on LFFR and DFS was outweighed by the degree of under-dosing. CONCLUSIONS: Treatment outcome of locally advanced NPC was significantly affected by the volume of under-dosed (<66.5 Gy) GTV_P due to the neighboring neurological structures. A new set of OAR dose constraint and specification is proposed.

Evolution of treatment for nasopharyngeal cancer--success and setback in the intensity-modulated radiotherapy era.

BACKGROUND AND PURPOSE: To assess the therapeutic gains and setbacks as we evolved from the 2-dimensional radiotherapy (2DRT) to conformal 3-dimensional (3DRT) and to intensity-modulated (IMRT) era. MATERIALS AND METHODS: 1593 consecutive patients from 1994 to 2010 were retrospectively analyzed. Evolving changes in the different era included advances in staging investigation, radiotherapy technique, dose escalation, and use of chemotherapy. RESULTS: The 3DRT era achieved significant improvement in local failure-free rate (L-FFR), disease-specific survival (DSS) and overall survival (OS). Neurological damage and bone/soft tissue necrosis were significantly reduced. However, the improvement in distant failure-free rate (D-FFR) was insignificant, and more hearing impairment occurred due to chemotherapy. Significantly higher D-FFR was achieved in the IMRT era, but L-FFR did not show further improvement. 5-Year DSS increased from 78% in the 2DRT, to 81% in the 3DRT, and 85% in the IMRT era, while the corresponding neurological toxicity rate decreased from 7.4% to 3.5% and 1.8%. CONCLUSIONS: Significant improvement in survival and reduction of serious toxicity was achieved as we evolved from 2DRT to 3DRT and IMRT era; the therapeutic ratio for all T-categories improved with more conformal techniques. Improvements in tumor control were attributed not only to advances in RT technique, but also to better imaging and increasing use of potent chemotherapy. However, it should also be noted that hearing impairment significantly increased due to chemotherapy, L-FFR reached a plateau in the 3DRT era, and it is worrisome that the result for T4 remained unsatisfactory. Besides exploring for more potent chemotherapy and innovative methods, the guideline on dose constraint should be re-visited to optimize the therapeutic ratio.