A feasibility study on adaptive 18F-FDG-PET-guided radiotherapy for recurrent and second primary head and neck cancer in the previously irradiated territory.

PURPOSE: To evaluate feasibility, disease control, survival, and toxicity after adaptive 18F-fluorodeoxyglucose (FDG) positron emisson tomography (PET) guided radiotherapy in patients with recurrent and second primary head and neck squamous cell carcinoma. METHODS: A prospective trial investigated the feasibility of adaptive intensity modulated radiotherapy (IMRT) ± concomitant cetuximab in 10 patients. The primary endpoint was achieving a 2-year survival free of grade >3 toxicity in ≥30% of patients. Three treatment plans based on 3 PET/CT scans were consecutively delivered in 6 weeks. The range of dose painting was 66.0-85.0 Gy in the dose-painted tumoral volumes in 30 fractions. RESULTS: Two-year locoregional and distant control rates were 38 and 76%, respectively. Overall and disease-free survival at 2 years was 20%. No grade 4 or 5 acute toxicity was observed in any of the patients, except for arterial mucosal hemorrhage in 1 patient. Three months after radiotherapy, grade 4 dysphagia and mucosal wound healing problems were observed in 1/7 and 1/6 of patients, respectively. Grade 5 toxicity (fatal bleeding) was seen in 2 patients, at 3.8 and 4.1 months of follow-up. Data on 2­year toxicity could only be assessed in 1 of the 2 surviving patients, in whom grade 4 mucosal wound healing problems were observed; no other grade >3 toxicity was observed. In this respect, a 30% 2­year survival free of grade >3 toxicity will not be achieved. CONCLUSIONS: Adaptive PET-guided reirradiation is feasible. However, due to slow accrual and treatment results that seemed inconsistent with achieving the primary endpoint, the trial was stopped early.

Helical tomotherapy in head and neck cancer: a European single-center experience.

BACKGROUND: We report on a retrospective analysis of 147 patients with early and locoregionally advanced squamous cell head and neck cancer (SCCHN) treated with helical tomotherapy (HT). PATIENTS AND METHODS: Included were patients with SCCHN of the oral cavity (OC), oropharynx (OP), hypopharynx (HP), or larynx (L) consecutively treated in one radiotherapy center in 2008 and 2009. The prescribed HT dose was 60-66 Gy in the postoperative setting (group A) and 66-70 Gy when given as primary treatment (group B). HT was given alone, concurrent with systemic therapy (ST), that is, chemotherapy, biotherapy, or both, and with or without induction therapy (IT). Acute and late toxicities are reported using standard criteria; locoregional failure/progression (LRF), distant metastases (DM), and second primary tumors (SPT) were documented, and event-free survival (EFS) and overall survival (OS) were calculated from the start of HT. RESULTS: Group A patients received HT alone in 22 cases and HT + ST in 20 cases; group B patients received HT alone in 17 cases and HT + ST in 88 cases. Severe (grade ≥ 3) acute mucosal toxicity and swallowing problems increased with more additional ST. After a median follow-up of 44 months, grade ≥2 late toxicity after HT + ST was approximately twice that of HT alone for skin, subcutis, pharynx, and larynx. Forty percent had grade ≥2 late xerostomia, and 29% had mucosal toxicity. At 3 years, LRF/DM/SPT occurred in 7%/7%/17% and 25%/13%/5% in groups A and B, respectively, leading to a 3-year EFS/OS of 64%/74% and 56%/63% in groups A and B, respectively. CONCLUSION: The use of HT alone or in combination with ST is feasible and promising and has a low late fatality rate. However, late toxicity is nearly twice as high when ST is added to HT.

The potential of helical tomotherapy in the treatment of head and neck cancer.

A decade after its first introduction into the clinic, little is known about the clinical impact of helical tomotherapy (HT) on head and neck cancer (HNC) treatment. Therefore, we analyzed the basics of this technique and reviewed the literature regarding HT's potential benefit in HNC. The past two decades have been characterized by a huge technological evolution in photon beam radiotherapy (RT). In HNC, static beam intensity-modulated radiotherapy (IMRT) has shown superiority over three-dimensional conformal RT in terms of xerostomia and is considered the standard of care. However, the next-generation IMRT, the rotational IMRT, has been introduced into the clinic without any evidence of superiority over static beam IMRT other than being substantially faster. Of these rotational techniques, HT is the first system especially developed for IMRT in combination with image-guided RT. HT is particularly promising for the treatment of HNC because its sharp dose gradients maximally spare the many radiosensitive organs at risk nearby. In addition, HT's integrated computed tomography scan assures a very precise dose administration and allows for some adaptive RT. Because HT is specifically developed for IMRT in combination with (integrated) image-guidance, it allows for precise dose distribution ("dose painting"), patient setup, and dose delivery. As such, it is an excellent tool for difficult HNC irradiation. The literature on the clinical results of HT in HNC all show excellent short-term (≤2 years) results with acceptable toxicity profiles. However, properly designed trials are still warranted to further substantiate these results.

RapidArc, SmartArc and TomoHD compared with classical step and shoot and sliding window intensity modulated radiotherapy in an oropharyngeal cancer treatment plan comparison.

BACKGROUND: Radiotherapy techniques have evolved rapidly over the last decade with the introduction of Intensity Modulated RadioTherapy (IMRT) in different forms. It is not clear which of the IMRT techniques is superior in the treatment of head and neck cancer patients in terms of coverage of the planning target volumes (PTVs), sparing the organs at risk (OARs), dose to the normal tissue, number of monitor units needed and delivery time.The present paper aims to compare Step and Shoot (SS) IMRT, Sliding Window (SW) IMRT, RapidArc (RA) planned with Eclipse, Elekta VMAT planned with SmartArc (SA) and helical TomoHD™ (HT). METHODS: Target volumes and organs at risk (OARs) of five patients with oropharyngeal cancer were delineated on contrast enhanced CT-scans, then treatment plans were generated on five different IMRT systems. In 32 fractions, 69.12 Gy and 56 Gy were planned to the therapeutic and prophylactic PTVs, respectively. For the PTVs and 26 OARs ICRU 83 reporting guidelines were followed. Differences in the studied parameters between treatment planning systems were analysed using repeated measures ANOVA. RESULTS: Mean Homogeneity Index of PTV(therapeutic) is better with HT(.06) followed by SA(.08), RA(.10), SW(.10) and SS(.11). PTV(prophylactic) is most homogeneous with RA. Parotid glands prescribed mean doses are only obtained by SA and HT, 20.6 Gy and 21.7 Gy for the contralateral and 25.6 Gy and 24.1 Gy for the ipsilateral, against 25.6 Gy and 32.0 Gy for RA, 26.4 Gy and 34.6 Gy for SW, and 28.2 Gy and 34.0 Gy for SS. RA uses the least monitor units, HT the most. Treatment times are 3.05 min for RA, and 5.9 min for SA and HT. CONCLUSIONS: In the treatment of oropharyngeal cancer, we consider rotational IMRT techniques preferable to fixed gantry techniques due to faster fraction delivery and better sparing of OARs without a higher integral dose. TomoHD gives most homogeneous target coverage with more sparing of spinal cord, brainstem, parotids and the lower swallowing apparatus than most of the other systems. Between RA and SA, SA gives a more homogeneous PTV(therapeutic) while sparing the parotids more, but the delivery of RA is twice as fast with less overdose to the PTV(elective).