Quantitative assessment of lung density changes after 3-D radiotherapy for breast cancer

Figures & data

Figure 1A.  Frontal image (Beam's-eye-view (BEV)) depicting the position of the frontal 6 MV photon beam covering the supraclavicular fossa and axilla. Barred areas are shielded. Green areas represent regions with post-RT density changes.

Table I.  Results of correlation test between CT scores and clinical radiation pneumonitis:

	Radiation pneumonitis
CT scores^1	None (Grade 0)^2	Mild (Grade 1)	Moderate (Grade 2)
0	14	0	0	G^3=0.66 (p = 0.1)
1–3	35	2	0
4–9	13	1	1

¹Modified and CT adapted Arriagada Classification. ²Common Toxicity Criteria. ³Gamma statistics.

Table II.  Results of tests of relation between co-variates and moderate/severe radiological changes and multivariate (MVA) modeling based on the four studied dosimetric factors.

Co-variates	Univariate analysis^1	MVA^2 V13	MVA V20	MVA V30	MVA MLD
Dosimetric factor	–	p = 0.1 (NS)	p = 0.1 (NS)	p = 0.08 (NS)	p = 0.09 (NS)
Age	p = 0.017	NS	NS	NS	NS
Pre-RT chemotherapy	p = 0.015	NS	NS	NS	NS
Pre-RT docetaxel	NS	–	–	–	–
Ongoing smoking	NS	–	–	–	–
Concurrent tamoxifen	NS	–	–	–	–
Concurrent anastrozol	NS	–	–	–	–
Concurrent trastuzumab	NS	–	–	–	–

¹Univariate logistic regression. ²Multivariate logistic regression (Wald-Enter). NS – not significant.

Figure 1B.  Frontal image (BEV) depicting the position of the frontal electron beam covering the chest wall and the IMN. Barred areas are shielded. Green areas represent regions with post-RT density changes.

Figure 1C.  Cumulative dose volume histograms for the entire ipsilateral lung (red) and for regions with post-RT density changes (green-dashed) (Normalized volumes; typical total lung volume about 1 200 ml and volume with density changes about 20 ml). The red vertical line illustrates the mean V20 value (±SD) for all 48 irradiated, mastectomized patients. The green horizontal line depicts the average mean dose (± SD) of the damaged lung subvolumes among the mastectomized patients with post-RT lung density changes.

Figure 2A.  Frontal image (BEV) depicting the position of the frontal photon beam covering the supraclavicular fossa and axilla. Green areas represent regions with post-RT density changes.

Figure 2B.  Lateral image (BEV) depicting the medial tangential photon beam. Green areas represent regions with post-RT density changes.

Figure 2C.  Cumulative dose volume histograms for the entire ipsilateral lung (blue) and for regions with post-RT density changes (green-dashed red). The teal line depicts the dose to the contralateral lung. The blue vertical line illustrates the mean V20 value (±SD) for all 14 irradiated, lumpectomized patients. The light brown horizontal line depicts the average mean dose (±SD) of the damaged lung subvolumes among the lumpectomized patients with post-RT lung density changes.