Tumor Volume Reduction Rate during Adaptive Radiation Therapy as a Prognosticator for Nasopharyngeal Cancer / Journal of the Korean Cancer Association, 대한암학회지

PURPOSE: The purpose of this study is to evaluate the prognostic significance of the tumor volume reduction rate (TVRR) measured during adaptive definitive radiation therapy (RT) for nasopharyngeal cancer (NPC). MATERIALS AND METHODS: We reviewed the RT records of 159 NPC patients treated with definitive RT with or without concurrent chemotherapy between January 2006 and February 2013. Adaptive re-planning was performed in all patients at the third week of RT. The pre- and mid-RT gross tumor volumes (GTVs) of the primary tumor and the metastatic lymph nodes were measured and analyzed for prognostic implications. RESULTS: After a median follow-up period of 41.5 months (range, 11.2 to 91.8 months) for survivors, there were 43 treatment failures. The overall survival and progression-free survival (PFS) rates at 5 years were 89.6% and 69.7%, respectively. The mean pre-RT GTV, mid-RT GTV, and TVRR were 45.9 cm3 (range, 1.5 to 185.3 cm3), 26.7 cm3 (1.0 to 113.8 cm3), and -41.9% (range, -87% to 78%), respectively. Patients without recurrence had higher TVRR than those with recurrence (44.3% in the no recurrence group vs. 34.0% in the recurrence group, p=0.004), and those with TVRR > 35% achieved a significantly higher rate of PFS at 5 years (79.2% in TVRR > 35% vs. 53.2% in TVRR ≤ 35%; p < 0.001). In multivariate analysis, TVRR was a significant factor affecting PFS (hazard ratio, 2.877; 95% confidence interval, 1.555 to 5.326; p=0.001). CONCLUSION: TVRR proved to be a significant prognostic factor in NPC patients treated with definitive RT, and could be used as a potential indicator for early therapeutic modification during the RT course.

Analysis of Criteria for Tumor Response after Preoperative Chemoradiation Therapy for Locally Advanced Rectal Cancer: Correlation between Tumor Volume Reduction and Histopathologic Downstaging

PURPOSE: Preoperative chemoradiation treatment (CCRT) for locally advanced rectal cancer has been known to be safe and effective. The aim of study is to find any correlation between tumor volume reduction and histopathologic downstaging in locally advanced rectal cancer by preoperative CCRT. METHODS: A total of 16 patients of rectal cancer were selected. They had been T3,4 N (+) preoperatively staged by using a transrectal ultrasonography and pelvic MRI. Radiation was given, a total of 5,040 cGy over 5 weeks, and systemic chemotherapy was also given 5 FU 450 mg/m2 and leucovorin 20 mg/m2 concurrently intravenously during the first and the fifth week of CCRT. Surgery was done 4~6 weeks after completion of CCRT. A 3D CT image was obtained with AcQsim PQ 5000 3D (Philips, USA). Tumor volume was measured before and after CCRT. RESULTS: The type of operative procedures were abdominoperineal resection 7, low anterior resection 5, coloanal anastomosis 3 and Hartmann operation 1. Volume reduction was ranged from 14.6% to 84.4%. Over a 50% tumor volume reductions were in 9 patients (56.2%). Pathologic complete remission was observed in 2 patients (12.5%), who showed 72% and 58.5% tumor volume reductions. Patients showing pT and/or pN downstaging patients (N=9) had a 55.9% tumor reductions (14.6~84.4%), and patients showing no pT and/or pN downstaging (N=7) had 51.8% volume reduction (24.7~79%). CONCLUSIONS: Preoeperative CCRT has been thought to be able to decrease tumor size and volume and to increase respectability. However, among our 9 patients who showed over 50% tumor volume reductions, 3 patients did not show any T and N downstaging, which is really important for long-term oncologic outcomes.