The Impact of Tumor Volume and Radiotherapy Dose on Outcome in Previously Irradiated Recurrent Squamous Cell Carcinoma of the Head and Neck Treated With Stereotactic Body Radiation Therapy

Abstract

Purpose To assess the effect of stereotactic body radiotherapy (SBRT) dose and tumor volume on outcomes in patients with recurrent, previously irradiated squamous cell carcinoma of the head and neck. Materials and Methods A total of 96 patients with recurrent, previously irradiated squamous cell carcinoma of the head and neck were treated with SBRT using Cyberknife and Trilogy-intensity-modulated radiosurgery. Kaplan-Meier survival analyses were used to estimate locoregional control (LRC) and overall survival rates. Response was evaluated using positron emission tomography/computed tomography or computed tomography and detailed physical examination. Results The median follow-up for all patients was 14 months (2–39 months). The median dose of prior radiation was 68.4 Gy (32–170 Gy). Patients were divided into 4 SBRT dose groups: I (15–28 Gy/n = 29), II (30–36 Gy/n = 22), III (40 Gy/n = 18), and IV (44–50 Gy/n = 27). The median gross tumor volume (GTV) was 24.3 cm3 (2.5–162 cm3). For GTV ≤25 cm3 (n = 50), complete response rates were 27.8%/30%/45.5%/45.5%, and for GTV >25 cm3 (n = 46), complete response rates were 20%/25%/42.8%/50% for SBRT groups I–IV, respectively. The 1-/2-/3-year LRC rates for doses 40 to 50 Gy were 69.4%/57.8%/41.1%, respectively, whereas for 15 to 36 Gy, they were 51.9%/31.7%/15.9%, respectively (P = 0.02). The overall 1- and 2-year overall survival rates were 58.9% and 28.4%, respectively. Treatment was well tolerated with no grade 4/5 toxicities. Conclusions Dose escalation up to 50 Gy in 5 fractions is feasible with SBRT for recurrent head and neck squamous cell carcinoma. Higher SBRT doses were associated with significantly higher LRC rates. Large tumor volume required higher SBRT doses to achieve optimal response rates compared with smaller tumor volume.

A Prospective Phase 2 Trial of Reirradiation With Stereotactic Body Radiation Therapy Plus Cetuximab in Patients With Previously Irradiated Recurrent Squamous Cell Carcinoma of the Head and Neck

“…In addition to disease-related factors, current comorbidities, age, and also the individual expectations of the patient and preexisting organ dysfunction have to be taken into account when selecting patients for reirradiation. Similarly, on unplanned subgroup analyses we validate the previously established importance of tumor volume < 25cc and present hypothesis-generating trends for the potential impact of re-challenging patients with cetuximab containing regimens who have failed a prior EGFR inhibitor (18). Limiting the SBRT treatment volume to the GTV, the 1-year local PFS was 60%, and the 1-year locoregional PFS was 37%; prior patterns of failure from IMRT series have supported a similar focus on the recurrence GTV, but this pattern begins to highlight the competing risk of locoregional failure especially given the 36% risk of failure in the uninvolved neck in patients treated for nodal recurrence (32).…”

“…Later, based on a patterns-of-failure analysis, the protocol was amended to allow a 3-ot 5-mm PTV expansion on the GTV (17). Tumors <25 cm 3 received 8.0 Gy per fraction for 5 fractions to 40 Gy; tumors !25 cm 3 received 8.8 Gy per fractions for 5 fractions to 44 Gy (18). SBRT was delivered on alternating days on an outpatient basis over 1 to 2 weeks.…”

“…One hundred percent of patients completed the prescribed SBRT plus cetuximab course with the median elapsed days for SBRT of 9 (range: [8][9][10][11][12][13][14][15][16][17][18][19][20], with only 4% requiring treatment interruptions (1 patient experienced a 2-day interruption for tumor-related pain control after the second SBRT fraction, and another patient had an 8-day interruption for a malfunctioning gastrostomy tube (G-tube) with associated abscess and enterocutaneous fistula). According to the protocol, the first [ 18 F]FDG PET-CT was performed 8 weeks post-treatment in 44 patients (92%).…”

Stereotactic radiotherapy with CyberKnife for a large angiosarcoma of the maxillary sinus: A case report

“…Recent reports have indicated the usefulness of these new techniques for the management of head and neck tumors [13][14][15][16][17][18]. The CyberKnife system is a robotic stereotactic radiosurgery/radiotherapy device that can deliver a high dose of radiation precisely and with minimal damage to surrounding tissue [19][20][21].…”

Monte Carlo evaluation of tissue heterogeneities corrections in the treatment of head and neck cancer patients using stereotactic radiotherapy

“…The University of Pittsburgh experience suggests a dose response with a trend toward improved survival with doses of 40 Gy or higher. (27) However, none of these studies reported Monte Carlo-computed dose distributions for the head and neck SRT patients. Our retrospective study demonstrated the feasibility of using Monte Carlo-based treatment planning and dose calculation for clinical head and neck SRT patients.…”