Adaptive FDG-PET/CT guided dose escalation in head and neck squamous cell carcinoma: Late toxicity and oncologic outcomes (The ADMIRE study)

Risk Stratification for Trial Enrichment Considering Loco-Regional Failure in Head and Neck Cancer: UICC8 Versus Purpose-Built Failure-Type Specific Risk Prediction Model

BACKGROUND

A previously published failure-type specific risk model showed good performance in the original cohort.

AIM

to validate the model and separate patients with high- and low-risk loco-regional failure (LRF).

GOAL

to identify patients potentially suitable for treatment intensification trials.

METHODS

Validation data: 756 patients from two institutions (different countries). Predictive performance was evaluated by Brier scores and AUCs. Discriminatory performance was compared to Union for International Cancer Control (UICC) staging (versions 7 and 8).

RESULTS

The model's 3-year AUC for LRF was 65%, significantly better than UICC7 staging, but no significant difference to UICC8. Model-based risk stratification and UICC8 both identified high-risk patient groups with 3-year LRF ≈30%. The population mean was 18%.

CONCLUSIONS

The model performed well on a group level. UICC8 staging performed equally well. Although developed for the endpoint of OS, an improvement from UICC version 7 to version 8 was evident also for the prediction of LRF.

Adaptive radiotherapy for head and neck cancer: Pitfalls and possibilities from the radiation oncologist's point of view

BACKGROUND

Patients with head and neck cancer (HNC) may experience substantial anatomical changes during the course of radiotherapy treatment. The implementation of adaptive radiotherapy (ART) proves effective in managing the consequent impact on the planned dose distribution.

METHODS

This narrative literature review comprehensively discusses the diverse strategies of ART in HNC and the documented dosimetric and clinical advantages associated with these approaches, while also addressing the current challenges for integration of ART into clinical practice.

RESULTS AND CONCLUSION

Although based on mainly non-randomized and retrospective trials, there is accumulating evidence that ART has the potential to reduce toxicity and improve quality of life and tumor control in HNC patients treated with RT. However, several questions remain regarding accurate patient selection, the ideal frequency and timing of replanning, and the appropriate way for image registration and dose calculation. Well-designed randomized prospective trials, with a predetermined protocol for both image registration and dose summation, are urgently needed to further investigate the dosimetric and clinical benefits of ART.

Phase I feasibility study of Olaparib in combination with loco-regional radiotherapy in head and neck squamous cell carcinoma

Purpose

PARP-inhibitors have potent radiosensitizing properties in pre-clinical models. To identify the maximum tolerated dose (MTD) of the PARP-inhibitor Olaparib in combination with radiotherapy in patients with head and neck cancer, a single institutional phase-I dose escalation trial was initiated.

Patients and methods

The starting dose of Olaparib was 25 mg BID, combined with radiotherapy (70 Gy in 35 fractions). The MTD was defined as the highest dose-level at which not more than 20 % of patients experience dose-limiting toxicities (DLT) or as the highest reached dose in the absence of DLT's.

Results

One week Olaparib-only treatment (25 mg QD) was administered to all patients prior to the start of radiotherapy. In dose-level I, Olaparib (25 mg BID) was combined with accelerated radiotherapy (70 Gy in 6 weeks). Because of DLT's in 3 of the 4 treated patients (acute tracheotomy 5 and 7 months and osteoradionecrosis 7 months after treatment), the Olaparib dose was de-escalated to 25 mg QD, and combined with conventional radiotherapy (70 Gy in 7 weeks) (dose-level II). There were no DLT's observed in 5 patients treated within dose-level II. After a median follow-up of 60 months, the 4-year LRC and OS rates were 77.8 % and 88.9 %, respectively.

Conclusion

Olaparib 25 mg QD combined with conventionally fractionated radiotherapy was well tolerated and identified as the MTD while severe DLT's were observed when Olaparib 25 mg BID was combined with accelerated radiation. This combination might be further explored in future Olaparib dose escalation studies in patients with locally-advanced HNSCC unfit for cisplatin-based chemoradiotherapy.