Teaching via Web Conference Increases Adherence to Breast Radiation Guidelines

A web-based teaching conference was found to be an effective teaching model to improve adherence to clinical pathway guidelines in a large radiation oncology network looking to improve compliance with dosimetric parameters in whole breast irradiation (WBI), according to a report published earlier this year.

Radiation treatment (RT) plans were collected for the 10 most recent patients receiving WBI at 16 institutions within the UPMC Hillman Cancer Center network in Pennsylvania. A web-based conference was conducted to educate staff physicians, physicists, and dosimetrists with goals for dose homogeneity and critical organ dosimetry. Six months post-conference, another 10 plans were collected from each site and compared to pre-conference plans for deviations from dosimetric criteria.

Analyses of phase 3 clinical trials have shown that major RT deviations had adverse impacts on toxicities, tumor control, and even survival outcomes, the authors wrote. The web-based conference encouraged practitioners to minimize deviations from dosimetric guidelines and improve care quality.

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Modalities such as 3-dimensional conformal radiation therapy (3D-CRT) and intensity modulated radiation therapy (IMRT) allow for assessment of dose distribution for the entire target volume, as opposed to only the central axis.

Dose homogeneity and critical organ dosimetry have become important targets to achieve in treatment planning, as improved dose homogeneity in breast irradiation has been shown to significantly decrease the risk of skin damage. There is also strong evidence that increased mean heart dose linearly increases risk for major coronary events, which is particularly important for left-sided tumors.

Clinical pathways have been used in practice in the UPMC Hillman Cancer Center network since 2003. The criteria are:

1. V_105% ≤ 10—15%, where V_105% is the breast volume receiving 105% of the prescription dose. Larger breasts can accept V_105% up to 15—20%, where 20% is the cutoff for meeting compliance.

2. V_110% = 0%, where V_110% is the breast volume receiving 110% of the prescription dose.

3. Mean heart dose <&thinsp;3 Gy. The heart was contoured as an organ at risk for both left and right breast irradiation.

The authors wrote that major variations in quality often occur during treatment planning and delivery in radiation oncology, and that these deviations are hard to capture.

Despite the specification of parameters for dose homogeneity and critical organ dosimetry, an internal audit showed that baseline adherence to dose homogeneity was suboptimal, which is what spurred the web conference.

After the conference, dose homogeneity significantly improved, with breast V₁₀₅% decreasing from 15.6% to 11.2% (P&thinsp;=&thinsp;0.004) and breast V₁₁₀% decreasing from 1.3% to 0.04% (P&thinsp; =.008). A higher percentage of cases were compliant with dosimetric criteria, with breast V₁₀₅%&thinsp;>&thinsp;20% decreasing from 22.5% to 7.5% of cases (P &thinsp;=.0002) and breast V₁₁₀%&thinsp;>&thinsp;0% decreasing from 13.8% to 4.4% of cases (P&thinsp; =.003).

The authors said there may be several potential barriers that may have affected compliance with clinical pathway recommendations.

For physicians, physicists, and dosimetrists who initially trained with 2D-RT for breast cancer, there may have been a general unfamiliarity with the importance of dose homogeneity.

Indeed, dose homogeneity guidelines themselves are not well defined in the literature. The only recommendation made in American Society for Radiation Oncology guidelines for WBI is to limit maximum breast dose to less than 107%, on the basis of randomized trials involving standard 2D-RT planning.

Reference

Chen KS, Glaser SM, Garda AE, et al. Utilizing clinical pathways and web-based conferences to improve quality of care in a large integrated network using breast cancer radiation therapy as the model. [published online March 16, 2018.] Radiat Oncol. doi: 10.1186/s13014-018-0995-0.