Two-year clinical experience with tomotherapy: the French national cancer institute project on implementing new technology

Results of radiotherapy in squamous cell laryngeal cancer: A tomotherapy center experience

Background

Laryngeal cancer is a common type of head and neck cancer (HNC). Radiotherapy (RT) is a mainstay for curative treatment. Intensity-modulated RT (IMRT) is a standard technique today, as it provides of higher survival and local control and lower normal tissue toxicity. One of IMRT devices is helical tomotherapy (HT). The HT treatment results of HNC patients have been reported in few studies. We aimed to investigate the results of squamous cell laryngeal carcinoma patients treated with helical tomotherapy.

Methods

Forty-five laryngeal cancer patients were selected according to the inclusion criteria. Radiotherapy (RT) plans were set in the Hi-Art HT planning system. Image-gated RT (IGRT) technique was used. Appropriate patients received simultaneous cisplatin. Treatment response rates were evaluated at the post-RT third and sixth months. Survival times were calculated with the Kaplan-Meier method. The factors affecting the treatment results were evaluated using Log-rank and Cox regression tests. A P value of less than 0.05 was accepted as statistically significant.

Results

The median age was 65 (28-84) years. The median symptom duration was 6 (1-60) months. The RT dose for the early and the locally advanced disease was median 63 Gy (60.75-66) and 66 Gy (60-70), respectively. The RT interruption was median two (0-20) days. The patients were followed up to 25 (1-45) months. Grade 2 xerostomia and dysphagia rates were 55% and 7%, respectively. The 3-year estimates of overall survival (OS), disease-free survival (DFS), metastasis-free survival (DMFS), and locoregional recurrence-free survival (RRFS) were 71.7%, 60.4%, 84.9%, and 68.5%, respectively. In univariate analysis, the presence of N2 disease was a negative prognostic for DFS (P = 0.05) and DMFS (P = 0.003). RT interruption >2 days was a negative prognostic for OS (P = 0.005), DFS (P = 0.02), and RRFS (P = 0.023). In the multivariate analysis, symptom duration >6 months was found to be the only significant factor for DFS (P < 0.05).

Conclusion

Intensity-modulated radiation with HT achieved comparable clinical outcomes with acceptable toxicity in laryngeal carcinoma.

Clinical Outcomes of Several IMRT Techniques for Patients With Head and Neck Cancer: A Propensity Score-Weighted Analysis

PURPOSE

The Advanced Radiotherapy Oto-Rhino-Laryngologie (ART-ORL) study (NCT02024035) was performed to prospectively evaluate the clinical and economic aspects of helical TomoTherapy and volumetric modulated arc therapy (RapidArc, Varian Medical Systems, Palo Alto, CA) for patients with head and neck cancer.

METHODS AND MATERIALS

Fourteen centers participated in this prospective comparative study. Randomization was not possible based on the availability of equipment. Patients with epidermoid or undifferentiated nasopharyngeal carcinoma or epidermoid carcinoma of the oropharynx and oral cavity (T1-T4, M0, N0-N3) were included between February 2010 and February 2012. Only the results of the clinical study are presented in this report, as the results of the economic assessment have been published previously. Inverse probability of treatment weighting using the propensity score analysis was undertaken in an effort to adjust for potential bias due to nonrandomization. Locoregional control, cancer-specific survival, and overall survival assessed 18 months after treatment, as well as long-term toxicity and salivary function, were evaluated.

RESULTS

The analysis included 166 patients. The following results are given after inverse probability of treatment weighting adjustment. The locoregional control rate at 18 months was significantly better in the TomoTherapy group: 83.3% (95% confidence interval [CI], 72.5%-90.2%) versus 72.7% (95% CI, 62.1%-80.8%) in the RapidArc group (P=.025). The cancer-specific survival rate was better in the TomoTherapy group: 97.2% (95% CI, 89.3%-99.3%) versus 85.5% (95% CI, 75.8%-91.5%) in the RapidArc group (P=.014). No significant difference was shown in progression-free or overall survival. TomoTherapy induced fewer acute salivary disorders (P=.012). Posttreatment salivary function degradation was worse in the RapidArc group (P=.012).

CONCLUSIONS

TomoTherapy provided better locoregional control and cancer-specific survival than RapidArc treatment, with fewer salivary disorders. No significant difference was shown in progression-free and overall survival. These results should be explored in a randomized trial.

Associative encoding and retrieval are predicted by functional connectivity in distinct hippocampal area CA1 pathways

Determining how the hippocampus supports the unique demands of memory encoding and retrieval is fundamental for understanding the biological basis of episodic memory. One possibility proposed by theoretical models is that the distinct computational demands of encoding and retrieval are accommodated by shifts in the functional interaction between the hippocampal CA1 subregion and its input structures. However, empirical tests of this hypothesis are lacking. To test this in humans, we used high-resolution fMRI to measure functional connectivity between hippocampal area CA1 and regions of the medial temporal lobe and midbrain during extended blocks of associative encoding and retrieval tasks. We found evidence for a double dissociation between the pathways supporting successful encoding and retrieval. Specifically, during the associative encoding task, but not the retrieval task, functional connectivity only between area CA1 and the ventral tegmental area predicted associative long-term memory. In contrast, connectivity between area CA1 and DG/CA3 was greater, on average, during the retrieval task compared with the encoding task, and, importantly, the strength of this connectivity significantly correlated with retrieval success. Together, these findings serve as an important first step toward understanding how the demands of fundamental memory processes may be met by changes in the relative strength of connectivity within hippocampal pathways.

The value of image-guided intensity-modulated radiotherapy in challenging clinical settings

OBJECTIVE

To illustrate the wider potential scope of image-guided intensity-modulated radiotherapy (IG-IMRT), outside of the "standard" indications for IMRT.

METHODS

Nine challenging clinical cases were selected. All were treated with radical intent, although it was accepted that in several of the cases the probability of cure was low. IMRT alone was not adequate owing to the close proximity of the target to organs at risk, the risk of geographical miss, or the need to tighten planning margins, making image-guided radiotherapy an essential integral part of the treatment. Discrepancies between the initial planning scan and the daily on-treatment megavoltage CT were recorded for each case. The three-dimensional displacement was compared with the margin used to create the planning target volume (PTV).

RESULTS

All but one patient achieved local control. Three patients developed metastatic disease but benefited from good local palliation; two have since died. A further patient died of an unrelated condition. Four patients are alive and well. Toxicity was low in all cases. Without daily image guidance, the PTV margin would have been insufficient to ensure complete coverage in 49% of fractions. It was inadequate by >3 mm in 19% of fractions, and by >5 mm in 9%.

CONCLUSION

IG-IMRT ensures accurate dose delivery to treat the target and avoid critical structures, acting as daily quality assurance for the delivery of complex IMRT plans. These patients could not have been adequately treated without image guidance.

ADVANCES IN KNOWLEDGE

IG-IMRT can offer improved outcomes in less common clinical situations, where conventional techniques would provide suboptimal treatment.