Poster Viewing Abstracts S463
Volume 84 Number 3S Supplement 2012 Poster Viewing Abstract 2648; Table
Mean dose (Gy) to right tongue mucosa and clinically observed OM grade based on NCI CTCAE
Meas aft replan
Highest OM grade on right tongue
Onset of OM
Duration (weeks) of OM with grade 2
JW RS AS DH
32.3 23.7 44.5 26.5
33.8 26.8 47.0 26.0
3 2 0 0
week 3 week 5 -
6 2 0 0
Y Y N Y
dose from treatment planning system (TPS). If the measured total dose was > 35 Gy, a re-plan was generated to reduce the mucosal dose, followed by re-measurement of the dose. The OM grade was monitored weekly and correlated to the measured mucosal dose. Monte Carlo (MC) method was also used to evaluate the impact of the implants on dose distributions. Two sets of MC calculations were performed per patient: one treating implants as bones and the other substituting implants with gold. Doses in the PTV and adjacent structures were compared for the two MC calculations. Results: As shown in the Table, the measured dose was similar to the TPS calculation, suggesting no significant dose enhancement due to metals. Patient AS had the highest dose on right tongue but did not develop OM in that area; the re-plan gave a new TPS dose of 28 Gy, but the measurement was unchanged, likely due to the large dose gradient in the area (w3.7 Gy/mm). MC calculations showed there was no significant difference in treating the dental fillings as bones (as in TPS) or as gold. Conclusions: This very small study suggested that it might not be feasible to optimize the IMRT plan based on measured tongue mucosal dose. This is related to: (1) large dose variation from positioning uncertainties of the dosimeter, (2) large dose gradient present in oral cavity, and (3) short range of the metallic scattering with negligible effect on tongue mucosa. However, a larger sample size is needed to confirm these observations. Acknowledgment: This work was supported by a Grant from Varian Medical System. Author Disclosure: L. Wang: None. E. Mok: None. L. Xing: None. B. Khong: None. W. Hara: None. Q. Le: E. Research Grant; Varian Medical System.
2649 Proton Beam Therapy Combined With Intra-arterial Infusion Chemotherapy for Locally Advanced Tongue Cancer K. Takayama, T. Nakamura, A. Takada, C. Makita, T. Kato, Y. Kikuchi, and N. Fuwa; Southern Tohoku Proton Therapy Center, Koriyama Fukushima, Japan Purpose/Objective(s): We report our results of proton beam therapy combined with selective intra-arterial infusion chemotherapy (PBT-IACT) for locally advanced tongue cancer. Materials/Methods: Between February 2009 and August 2011, 34 cases of stage III-IV(M0, SCC) tongue cancer (23 men and 11 women) were treated with PBT-IACT, and followed-up at least six months. Median age was 59 years (range: 25-83 years). Clinical stage III/IVA/IVB were 7/26/1, respectively. Basically, 2 courses of systemic chemotherapy and 36Gy of prophylactic wide field X-ray therapy were performed. Then, for local advanced tumor, 33GyE of proton beam therapy (PBT) and intra-arterial infusion chemotherapy via the superficial temporal artery by continuous infusion of cisplatin with sodium thiosulphate was delivered. Systemic chemotherapy was performed only for age of 70 years or younger. PBT was also performed for lymph node metastases in 28 cases (N1/N2b/N2cZ13/6/9). Median dose of X-ray therapy was 36Gy in 20 fractions (range: 28.6-50.6Gy), median dose of PBT was 33GyE in 15 fractions (range: 22-41.8GyE). Results: All except 1 case completed this therapy. The median follow-ups was 20 months (range: 8-40 months). Overall survival rate at 2 years was 91.2% (stage III:100.0%; stage IV: 88.9%). Local control rate at 2 years was 79.4% (stage III: 100.0%; stage IV: 73.0%). Disease-free survival rate at 2 years was 76.4%. Local control rate of cervical lymph node metastases at 2 years was 85.7%. As the early toxic event, grade 3 mucositis (22/34) and blood/bone marrow toxicity (15/34) were observed. Within 6 months after this therapy, mandibular osteomyelitis occurred in 1 case.
Conclusions: PBT-IACT seemed to be safe and showed high local control rate for stage III-IV locally advanced tongue cancer. It was not inferior to the results of surgery. This therapy could be a new effective therapy for locally advanced tongue cancer. Author Disclosure: K. Takayama: None. T. Nakamura: None. A. Takada: None. C. Makita: None. T. Kato: None. Y. Kikuchi: None. N. Fuwa: None.
2650 Recurrence Before Postoperative Radiation Therapy in Head-andNeck Squamous Cell Carcinoma M. Yao,1 R. Rezaee,1 C.A. Zender,1 P. Savvides,1 M. Lu,2 D.P. Hsu,1 J. Wasman,1 M. Machtay,1 and P. Lavertu1; 1University Hospitals Case Medical Center, Cleveland, OH, 2School of Public Health, University of Nevada at Reno, Reno, NV Purpose/Objective(s): To determine the incidence and pattern of recurrences in locally advanced head and neck squamous cell carcinoma (HNSCC) after surgery before starting adjuvant radiation. Materials/Methods: This is a retrospective review of patients treated in a single institute from August 2008 to February 2012. A total of 54 patients underwent postoperative radiation. Those with salivary gland, naso-sinal and skin cancer are excluded. The remaining 41 patients are included in this analysis. All patients with biopsy confirmed or suspected local regional recurrence by CT or PET imaging that necessitate change in radiation dose fractions routinely given in postoperative setting are censored as recurrence. Results: There were 31 males and 10 females with a median age of 62. The primary sites included oral cavity 23, oropharynx 12, larynx 5, and unknown primary 1. The median interval from surgery to starting radiation was 46 days (range: 28 - 163). There were 8 patients (19.5%) with local or regional recurrences, 5 with oral cavity and 3 with oropharyngeal cancer. The interval from surgery to recurrence was 43.5 days (range: 18 - 134). For 3 oropharyngeal patients, all had suspicious contralateral neck nodes, 2 in treatment planning CT, 1 in PET-CT before simulation. These nodes were treated to 70 Gy. For 5 oral cavity patients, all had gross recurrent diseases by physical exam and/or in PET-CT; 2 in primary site alone, 1 in neck alone, and 2 in both primary site and neck. Of these 5 patients, 2 had prolonged interval from surgery due to patient noncompliance and their recurrent diseases were detected before simulation. The remaining 3 patients had recurrences detected shortly after initial simulation before starting radiation. For these 3 patients, new treatment plans with new planning CT were necessary to encompass all disease and high risk areas. PET scan was often needed to differentiate the recurrent tumor from reconstructed flap. Initial analysis did not show significant association of these recurrences with primary site, T stage, N stage, margin status, perineural invasion, lymphovascular invasion, extracapsular extension, p16, and interval from surgery to radiation. Conclusions: About 20% of patients may have local regional recurrence after surgery before even starting adjuvant radiation. This may partly explain the poor outcome of postoperative radiation therapy in high risk HNSCC. Careful examination and FDG PET will be necessary in these patients before radiation. Attempts to identify risk factors were not successful possible due to small sample size. Further studies with a larger patient population are needed. Author Disclosure: M. Yao: None. R. Rezaee: None. C.A. Zender: None. P. Savvides: None. M. Lu: None. D.P. Hsu: None. J. Wasman: None. M. Machtay: None. P. Lavertu: None.