Usefulness of Induction Chemotherapy Followed by Chemoradiation in the Treatment of Oropharyngeal Carcinoma

International Journal of Radiation Oncology  Biology  Physics

S434 Poster Viewing Abstract 2603; Table 30 years

Evolving treatment modalities over

2002-2011 1992-2001 1981-1991 No. (% total in No. (% total in No. (% total in decade) decade) decade) Surgery alone Surgery + postopRT RT (2D or 3D EBRT+/-IB) ChemoRT (2D or 3D EBRT+/-IB) RT (IMRT+SIB) ChemoRT (IMRT+/-SIB) Total

2 4 30 7

(5%) (9%) (70%) (16%)

0 (0%) 0 (0%) 43

4 22 46 19

(4%) (24%) (51%) (21%)

0 (0%) 0 (0%) 91

6 21 1 12

(6%) (22%) (1%) (12%)

1 (1%) 56 (58%) 97

38%, respectively. Three pts developed grade 3 acute skin reactions (CTCAE ver. 4.0). Ten pts developed grade 3 acute mucosal reactions. There were no severe late complications. One patient had percutaneous endoscopic gastrostomy because of dysphagia. Conclusions: Responders after induction chemotherapy using TPF or PF appeared to be good candidates for definitive concurrent chemoradiation. Chemo-selection appears to be helpful in choosing optimal treatment for patients with oropharyngeal carcinoma. Author Disclosure: T. Yanagi: None. Y. Hattori: None. R. Takenaka: None. M. Iwabuchi: None. S. Miyakawa: None. C. Sugie: None. F. Baba: None. H. Ogino: None. Y. Mori: None. Y. Shibamoto: None.

2605 (p Z .01). Grade  3 esophageal or pharyngeal stenosis, osteoradionecrosis, and trismus were seen in 7, 9, and 4 patients. Conclusions: To improve functional preservation and maintain clinical efficacy, treatment modalities for base-of-tongue carcinoma have shifted to increasing utilization of definitive chemoRT, and radiation techniques have shifted from EBRT+IB to chemoIMRT. The use of chemoIMRT-SIB is associated with significantly improved LC, LRC, and OS compared to other radiation techniques. Author Disclosure: A.L. Chen: None. C.J. Anker: None. J. Hunt: None. B.G. Bentz: None. L. Buchmann: None. K. Grossmann: None. L.C. Fang: None. D.C. Shrieve: None. Y.J. Hitchcock: None.

2604 Usefulness of Induction Chemotherapy Followed by Chemoradiation in the Treatment of Oropharyngeal Carcinoma T. Yanagi, Y. Hattori, R. Takenaka, M. Iwabuchi, S. Miyakawa, C. Sugie, F. Baba, H. Ogino, Y. Mori, and Y. Shibamoto; Department of Radiology, Nagoya City University, Nagoya, Japan Purpose/Objective(s): To evaluate the usefulness of induction chemotherapy for selecting good candidates for definitive concurrent chemoradiation therapy in the treatment of oropharyngeal carcinoma. Materials/Methods: Thirty-nine patients (pts) with oropharyngeal carcinoma received induction chemotherapy followed by definitive chemoradiation therapy or radiation therapy. The median patient age was 69 years (range, 39-82 years), and 35 were men and 4 were women. Tumor sites were the tonsil in 29, the base of tongue in 6, the soft palate in 2, and the posterior wall in 2. The T (tumor) and N (node) stage was as follows: T1, 3; T2, 20; T3, 6; T4a, 7; T4b, 3; N0, 5; N1, 7; N2a, 1; N2b, 13; N2c, 9; and N3, 4. Stage was I in 1, II in 2, III in 6, IVa in 25 and IVb in 5. Our treatment strategy was as follows; when patients had a partial response (PR) or a complete response (CR) after induction chemotherapy, definitive concurrent chemoradiation was recommended. When patients had a stable disease (SD) or a progressive disease (PD), surgery was recommended, but if the patients refused surgery, definitive chemoradiation was performed. Regimens of induction chemotherapy were TPF (docetaxel 60 mg/m2 day 1, cisplatin 70 mg/m2 day 1, 5-FU 600 mg/m2 day 1-5; 19 pts), CF (cisplatin 70 mg/m2 day 1, 5-FU 700 mg/m2 day 1-5: 16 pts), or others (4 pts). In all patients, conventional radiation therapy was given once daily to a total dose of 65-70 Gy. Nineteen pts received radiation therapy concurrently with administration of carboplatin (AUC Z 1 weekly: 13 pts) or docetaxel (10 mg/m2 weekly: 6 pts). Associations between clinical data including age, sex, performance status, tumor site, T-stage, N-stage, stage, response to induction chemotherapy, and local control (LC) or overall survival (OS) were analyzed. Results: Follow-up periods for living patients were 9-170 months (median, 40). Neck dissection was performed for lymph node metastases in 19 pts before or after radiation therapy. The 5-year LC and OS rates for all 39 pts were 81% and 60%, respectively. The rates for the 25 stage IVa patients were 73% and 46%, respectively. Response to induction chemotherapy was a significant factor for LC and OS. The 5-year LC and OS rates of induction-chemotherapy responders (CR + PR) were 89% and 65%, respectively, whereas those of non-responders (SD + PD) were 34% and

Outcomes of Diabetic Metformin Versus Nonmetformin Users With Oropharynx Carcinoma Treated With IMRT R. Chin, J. Lee, T. DeWees, P. Dyk, H. Gay, and W. Thorstad; Washington University School of Medicine, St. Louis, MO Purpose/Objective(s): Previous retrospective cohort studies in cancer sites such as breast, colon, and liver showed that metformin use is correlated with improved overall survival. However, the effect of metformin on outcomes in head and neck cancers is not as well established. We retrospectively reviewed the outcomes of ever- versus never- metformin use in type II diabetic (T2D) patients with oropharynx carcinoma who completed IMRT in the definitive or adjuvant setting. Materials/Methods: Using our institutional registry, 572 oropharyngeal cancer patients treated with IMRT between 1997 and 2012 were identified. Sixty-six (11.5%) were diagnosed with T2D before the start of RT, of which 37 had ever received metformin since their cancer diagnosis. We compared the OS, LC, LRC, and DMFS of these 37 T2D ever-metformin users with 29 T2D never-metformin users using univariate Kaplan-Meier curves with log-rank tests and multivariate Cox proportional hazards analyses. The multivariate analyses accounted for p16 status, age, race, BMI, sex, clinical stage, ACE-27 comorbidity index, RT goal, duration of diabetes since cancer diagnosis, and other diabetic drug treatments, such as the use of insulin and other classes of oral hypoglycemics. Results: T2D ever-metformin users had a significantly higher mean BMI (p Z 0.045) by the Wilcoxon rank-sum test and were more likely to receive combined therapy for T2D (p Z 0.002) by Fisher’s exact test. At a median follow-up of 24 months for living patients, log-rank tests showed no significant differences between the ever- and never-metformin groups in OS (71.1% vs 72.1% at 2 years, p Z 0.501), LC (91.0% vs 78.0% at 2 years, p Z 0.102), LRC (84.2% vs 70.4% at 2 years, p Z 0.114), and DMFS (83.1% vs 85.6% at 2 years, p Z 0.689). p16+ patients had significant better OS than the p16- patients in the never-metformin users (90.0% vs 50.0% at 2 years, p Z 0.008) and trends towards significance in the ever-metformin users (82.7% vs 50.0% at 2 years, p Z 0.062). In all patients, p16+ patients also had significantly better overall survival (84.9% vs 50.0% at 2 years, p16+ HR Z 0.185, p Z 0.002). Conclusions: No statistically significant differences in OS and DMFS were found between T2D ever- and never-metformin groups with oropharynx carcinoma, though a non-significant trend for improved LC and LRC for ever-metformin users was observed. The small sample size led to low power for detecting a difference. Consistent with past reports, p16+ patients had significantly better OS than p16- patients. Larger-scale retrospective with longer follow-up and prospective studies are necessary to better understand the effects of metformin on head and neck cancer outcomes. Author Disclosure: R. Chin: None. J. Lee: None. T. DeWees: None. P. Dyk: None. H. Gay: None. W. Thorstad: None.

2606 Analysis of Treatment Costs and Outcomes With the Addition of Induction Chemotherapy (IC) to Concurrent Chemoradiation (CRT) for Oropharyngeal Squamous Cell Carcinoma (OPSCC) E.F. Crandley,1 D.D. Wilson,1 A. Sim,1 N. Blackburn,1 L. Wang,1 A.S. Rahimi,2 E.B. Stelow,1 M.J. Jameson,1 D.C. Shonka,1