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OBJECTIVE: To analyse the extent to which primary systemic therapy (PST) achieves the main goals in patients with operable primary breast cancer, these goals being breast-conserving therapy and pathological complete remission (pCR), and to evaluate the response. DESIGN: Retrospective. METHOD: In a retrospective analysis of 254 patients treated with PST in 2000-2007 in the Netherlands Cancer Institute-Antoni van Leeuwenhoek Hospital, patients with inoperable disease (T4 and/or N3) were excluded. The response was mostly evaluated using contrast-enhanced MRI, whereby the chemotherapy regimen was switched if the reduction in the largest diameter of contrast washout was less than 25%. pCR was defined as no evidence of invasive cancer in the breast and axilla in the resection specimen. RESULTS: In patients with ductal carcinoma and lobular carcinoma an increase in breast-conserving therapy was seen in 32% and 17% of patients respectively. The pCR rate was 12% and 2% respectively. Secondary mastectomy because of irradical resection was required in 3% and 50% respectively. Multivariate analysis indicated that molecular type, defined on the basis of the expression of hormone receptors and human epidermal growth factor receptor 2 (HER2), i.e. luminal (oestrogen receptor-positive), basal (hormone receptor-negative and HER2-negative) and HER2-positive tumours treated with trastuzumab was the only independent predictor of pCR; 2%, 28% and 35% respectively (p=0.004). In 43 patients the chemotherapy regimen was adjusted because the tumour did not respond sufficiently. A favourable clinical response was observed in 72% (31/43) of these patients. CONCLUSION: The observed increase in the number of breast-conserving therapies after PST was clinically relevant. PST may be more effective when contrast-enhanced MRI is used for interim evaluation, based on which the treatment may be switched. There was a clear difference in histological and molecular types of tumour and therefore the choice of treatment may be adjusted accordingly

A new method is presented for inspection of patient setup in radiation therapy by automatic comparison of the patient position relative to the beam position in portal and simulator images. Quantification of patient-setup errors in terms of translation, rotation, and magnification is achieved by chamfer matching, a robust technique to match drawings and images, which is applied to both anatomy outlines and field edges. Applied to field edges, chamfer matching detects and visualizes deviations in field shape. Applied to anatomy outlines, the matching procedure quantifies and visualizes deviations in patient position relative to the radiation field. To test the method and to judge its feasibility, its behavior for four hundred different patient-setup deviations, which were simulated in four clinical images, was examined. These images show a top view of the pelvic region. The performance was measured in terms of accuracy and success rate for numerous cost functions and distance codings associated with the chamfer matching procedure. An average accuracy of 1.8 mm was found, a success rate of 90%, and an average overall computation time of 3 s on a 486 microcomputer. The whole analysis procedure is fast enough to allow on-line application.

Two computer methods for matching digital line drawings have been tested for automatic on-line verification of the radiation field shape during radiotherapy. This work is part of a research program aiming at automated inspection of on-line acquired digital portal images. Both methods, moment normalization and point distance minimization, compare the field edge detected in the portal image with the intended field edge and the beam shaping devices marked in the simulator image. Tests showed that the methods should be used together. First, shape deviations in the detected field edge are classified quickly, in less than a second (25 MHz 386 + 387 PC), as large (e.g., missing blocks) or small (e.g., shifts of a few mm) by moment normalization. Then the portal image is mapped to the simulator image by field edge alignment with a translation and magnification obtained from moment normalization and a rotation from point distance minimization. The mapped portal image and the simulator image juxtaposed on a monitor screen for visual inspection. Finally, the small field shape deviations are detected by an analysis of the relationship between the radiation field shape and the positioning of field shaping devices using point distance minimization.

In our institute, we have developed an electronic portal imaging system based on a matrix of 256 x 256 ionisation chambers. By improvements to the electronics, the system produces images with the same quality as the original system but 3-10 times faster. Software for automatic image analysis has been applied to more than 10,000 images over the last two years. Using an off-line correction strategy, the systematic patient set-up error has been limited to 5 mm or less for 98% of the patients treated for prostate cancer