Adjuvant simultaneous integrated boost IMRT for patients with intermediate- and high-risk head and neck cancer: outcome, toxicities and patterns of failure

Matched-pair analysis of the impact of low-dose postoperative radiotherapy on prognosis in patients with advanced hypopharyngeal squamous cell carcinoma without positive surgical margins and extracapsular extension

Background

We conducted a comparative analysis between low and high-dose postoperative radiotherapy in patients with hypopharyngeal squamous cell carcinoma (HPSCC) in stage III or IV without positive surgical margins and extracapsular extension (ECE). Propensity score matching (PSM) was used to eliminate confounding factors and reduce bias.

Methods

The matched-pair analysis included 156 patients divided into two groups: the low-dose radiotherapy group (LD-RT 50 Gy, 78 cases) and the high-dose radiotherapy group (HD-RT 60 Gy, 78 cases). Both cohorts were statistically comparable in terms of age, gender, subsite, and TNM classification.

Results

The median follow-up time was 49 months (ranging from 5 to 100 months). The overall survival (OS) rate, progression-free survival (PFS) rate, locoregional control rate (87% vs. 85.7%; p = 0.754), distant metastases-free survival (79.2% vs. 76.6%; p = 0.506), and the occurrence of second primary tumors (96.1% vs. 93.5%; p = 0.347) showed no significant differences between the LD-RT group and the HD-RT group. The 3-year OS was 64.9% and 61% in the low-dose and high-dose group, respectively, and 63% in the entire group (p = 0.547). The 3-year PFS was 63.6% and 54.5% (p = 0.250), respectively, and the 3-year PFS of the entire group was 59.1%. Multivariate analyses revealed that pathological T and N classification, and pathological differentiation were associated with 3-year OS, PFS, and LRFS and were independent prognostic factors (p < 0.05). LD-RT was not associated with an increased risk of death and disease progression compared to HD-RT.

Conclusion

The results of postoperative low-dose radiotherapy did not show inferiority to those of high-dose radiation for patients with advanced hypopharyngeal cancer without positive surgical margins and ECE in terms of OS, PFS, locoregional control, and metastases-free survival.

Origin of Locoregional Recurrences After Definitive Intensity-modulated Radiation Therapy (IMRT) for Laryngeal Cancer Determined Based on Follow-up PET/CT Imaging

Purpose: The aim of our study was to report on patterns of failure using detailed information from follow-up positron emission tomography-computed tomography (PET/CT) scans for patients with laryngeal squamous cell carcinoma (SCCA) treated with definitive radiation therapy using intensity-modulated radiation therapy (IMRT).

Methods: One hundred and sixty-eight patients with laryngeal SCCA treated with definitive IMRT using a simultaneous integrated boost were included. The point of recurrence origin on follow-up PET/CT was determined using two separate data-driven methods. The first method, the mathematical epicenter point of origin (PO_Epi), calculated the mathematical focal epicenter point for which the maximum distance to the surface of the surrounding volume was smaller than for any other point. The second method, maximum standardized uptake value point of origin (PO_Max), calculated the voxel with maximum standardized uptake value (SUV) uptake within the recurrence volume. The failure pattern was then determined by whether the point of recurrence origin fell within the low, intermediate, or high-risk target volumes in the original treatment planning CT.

Results: Thirty-five primary/nodal recurrences in 33 patients were included in the analysis. In the PO_Epi method, 94% (33/35) of all recurrences originated either within the high-risk gross tumor volume (GTV_High-risk) or within an average of 0.9 ± 1.3 mm from it. In the PO_Max method, 91% (32/35) of all recurrences originated either within the GTV_High-risk or within an average of 1.8 ± 1.7 mm from it. There were no recurrences outside the low-risk planning target volume (PTV_Low-risk) for the PO_Epi method but there was one for the PO_Max method, which was 19.8 mm away from the edge of the gross tumor volume receiving 70 Gy (GTV₇₀). Increasing distance between the two different origin points was strongly correlated with the size of the recurrence volume.

Conclusion: The majority of recurrences for laryngeal cancer patients treated with definitive IMRT originated from within the high-dose treatment region. This can have implications for reducing clinical target volumes while using a risk-adaptive treatment approach to both constrain dose to critical areas and further escalate the dose to the gross tumor to improve locoregional control rates.

Intensified intensity-modulated radiotherapy in anal cancer with prevalent HPV p16 positivity

AIM: To investigate the toxicity and response of intensity-modulated radiotherapy schedule intensified with a simultaneous integrated boost in anal canal cancer.

METHODS: From March 2009 to March 2014, we retrospectively analyzed 41 consecutive patients treated with intensity-modulated radiotherapy (IMRT) and concurrent chemotherapy for anal canal squamous cell carcinoma at our center. Radiotherapy was delivered via simultaneous integrated boost (SIB) technique by helical tomotherapy, and doses were adapted to two clinical target volumes according to the tumor-node-metastasis (TNM) stage: 50.6 Gy and 41.4 Gy in 23 fractions in T1N0, 52.8 Gy and 43.2 Gy in 24 fractions in T2N0, and 55 Gy and 45 Gy in 25 fractions in all patients with N positive and/or ≥ T3, respectively, to planning target volumes 1 and 2. The most common chemotherapy regimen was 5-fluorouracil and mitomycin-based. Human papilloma virus (HPV) p16 expression was performed by immunohistochemistry and evaluated in the majority of patients. Acute and late toxicity was scored according to CTCAe v 3.0 and RTOG scales.

RESULTS: The median follow-up was 30 mo (range: 12-71). Median age was 63 years (range 32-84). The stage of disease was: stage I in 2 patients, stage II in 13 patients, stage IIIA in 12 patients, and stage IIIB in 14 patients, respectively. Two patients were known to be HIV positive (4.9%). HPV p16 expression status was positive in 29/34 (85.3%) patients. The 4-year progression-free survival and overall survival in HPV-positive patients were 78% and 92%, respectively. Acute grade 3 skin and gastrointestinal toxicities were reported in 5% and 7.3% of patients, respectively; patients’ compliance to the treatment was good due to a low occurrence of severe acute toxicity, although treatment interruptions due to toxicity were required in 7.3% of patients. At 6 mo from end of treatment, 36/40 (90%) patients obtained complete response; during follow-up, 5 (13.8%) patients presented with disease progression (local or systemic).

CONCLUSION: In our experience, intensified SIB-IMRT with chemotherapy is very feasible in clinical practice, with excellent results in terms of overall survival and local control.