RT protocol compliance and outcome for H&N cancer

JCO: In addition to reporting out the negative results of tirapazamine, the TROG investigators reported on those with protocol violations, and found at SS worse over all survival (HR = 2!) and local control. i.e. - expertise does matter, at least for H&N RT.

Link and Abstract:

Critical Impact of Radiotherapy Protocol Compliance and Quality in the Treatment of Advanced Head and Neck Cancer: Results From TROG 02.02 [Head and Neck Cancer]: "Purpose

To report the impact of radiotherapy quality on outcome in a large international phase III trial evaluating radiotherapy with concurrent cisplatin plus tirapazamine for advanced head and neck cancer.

Patients and Methods

The protocol required interventional review of radiotherapy plans by the Quality Assurance Review Center (QARC). All plans and radiotherapy documentation underwent post-treatment review by the Trial Management Committee (TMC) for protocol compliance. Secondary review of noncompliant plans for predicted impact on tumor control was performed. Factors associated with poor protocol compliance were studied, and outcome data were analyzed in relation to protocol compliance and radiotherapy quality.

Results

At TMC review, 25.4% of the patients had noncompliant plans but none in which QARC-recommended changes had been made. At secondary review, 47% of noncompliant plans (12% overall) had deficiencies with a predicted major adverse impact on tumor control. Major deficiencies were unrelated to tumor subsite or to T or N stage (if N+), but were highly correlated with number of patients enrolled at the treatment center (< five patients, 29.8%; ≥ 20 patients, 5.4%; P < .001). In patients who received at least 60 Gy, those with major deficiencies in their treatment plans (n = 87) had a markedly inferior outcome compared with those whose treatment was initially protocol compliant (n = 502): –2 years overall survival, 50% v 70%; hazard ratio (HR), 1.99; P < .001; and 2 years freedom from locoregional failure, 54% v 78%; HR, 2.37; P < .001, respectively.

Conclusion

These results demonstrate the critical importance of radiotherapy quality on outcome of chemoradiotherapy in head and neck cancer. Centers treating only a few patients are the major source of quality problems.

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