The impact of publication of Australian treatment recommendations for DCIS on clinical practice: a population-based, "before-after" study

BACKGROUND: Clinical practice guidelines/recommendations have been promoted as a mechanism for ensuring evidence-based medicine. We examine the impact of the publication of Australian treatment recommendations (ATR) for ductal carcinoma in situ (DCIS) on clinical practice and surgeons' attitudes to the ATR. METHODS: All new cases of DCIS diagnosed in the 12-months immediately before the ATR release (pre-ATR: September 2002 to August 2003) and three years later (post-ATR: September 2006 to August 2007) were identified from the state of Victoria's population cancer registry. Treatment information, extracted for each case by treating surgeon or study manager, was available for 342 of 353 (97%) tumours pre-ATR and 371 of 378 (98%) tumours post-ATR. Sixty-three surgeons (58% response) completed a survey on awareness and attitudes to the ATR. RESULTS: The proportion of cases undergoing image-guided biopsy, or breast conservation surgery (BCS) did not change between surveys nor did extent of surgical margins. Compared to the pre-ATR period, more BCS cases were referred to a radiation oncologist (67% versus 58%) and more received radiotherapy (53% versus 44%) post-ATR. Tumours greater than 20 mm, of intermediate grade and moderate necrosis were more likely to receive radiotherapy post-ATR. While surgeons agreed with most recommendations, items reflecting radiotherapy recommendations generated most disagreement. CONCLUSION: With the possible exception of adjuvant radiotherapy, most DCIS cases were treated according to treatment recommendations before the ATR's release. The lack of change in radiotherapy for low grade, smaller tumours may reflect surgeon's uncertainty regarding this therapy for all BCS treated cases.