Radiothérapie des carcinomes canalaires in situ : impact du complément d’irradiation du lit tumoral

Quality assurance program and early toxicities in the phase III BONBIS randomized trial evaluating the role of a localized radiation boost in ductal carcinoma in situ

PURPOSE

To describe the quality assurance (QA) program and early toxicities in the phase III randomized trial BONBIS (NCT00907868) on the role of a localized radiation boost in ductal carcinoma in situ (DCIS).

MATERIALS AND METHODS

From November 2008 to July 2014, 2004 patients were randomized in arm A (only whole breast radiotherapy, WBRT) and arm B (WBRT + boost). The QA program involved 44 participant centers that performed the dummy run (DR). Compliance and uniformity of clinical target volume (CTV) delineations, and dose prescription and delivery according to the BONBIS trial radiotherapy guidelines were analyzed. Acute toxicities (during and up to 3 months after radiotherapy completion, NCI-CTCAE v3.0 classification) were evaluated in 1929 patients.

RESULTS

The differences in whole breast CTV (CTV1) and planning target volume (PTV1) were ≤10%, and the differences in boost CTV (CTV2) and PTV (PTV2) were ≥20% compared with the reference DR values; 95% of the prescribed dose encompassed 98.7% and 100% of the median CTV1 and CTV2. Grade ≥2 breast erythema (38.3% vs. 22.4% of grade 2 and 5.4% vs. 2.1% of grade 3, p < 0.001), grade ≥2 dermatitis (2.8% vs. 0.7%, p < 0.001), and grade 2 hyperpigmentation (6.9% vs. 3.6%, p = 0.005) were more frequent in arm B than arm A. No acute lung or cardiac toxicity was observed. Smoking history, large breast size, and large breast CTV were strong predictive factors of grade ≥2 acute skin toxicities.

CONCLUSIONS

The QA program showed deviations in breast and tumor bed delineation. The boost significantly increased acute skin toxicities.

Adjuvant therapy in patients with ductal carcinoma in situ of the breast: The Pandora's box

Most patients with ductal carcinoma in situ of the breast (DCIS) are eligible for breast conservation treatment. The key management decision is whether to add radiotherapy and/or endocrine therapy to minimize the risk of a subsequent recurrence. Recent analyses indicating a lack of benefit in terms of breast cancer-associated mortality have suggested that more conservative approaches, omitting adjuvant therapy or even surgery, may be advisable in selected patients. These mortality observations are directly influenced by widespread use of mammographic screening which has opened a Pandora's box of subclinical DCIS and early invasive lesions. Confusion as to how aggressively such possibly indolent lesions should be treated has led to misunderstandings among patients and medical professionals. While awaiting further prospective evidence from clinical trials, we endorse an active treatment of DCIS as the standard of care. Our rationale is twofold: invasive recurrences are associated with an increase in breast cancer mortality, which is not the only relevant endpoint for DCIS. The benefit of complete surgical excision, adjuvant radiotherapy and endocrine treatment in preventing recurrence and invasive progression has been demonstrated in DCIS. The challenge now is how to identify DCIS patients who will not progress to invasive carcinoma even without complete excision and, at the other extreme, those patients at the highest risk who require mastectomy for local control. The current controversies over whether and which adjuvant therapy should be implemented can at least in part be addressed by developing effective doctor-patient communications that enable mutual understanding about the management of this biologically heterogeneous disease.

Hypofractionation with simultaneous integrated boost for early breast cancer: results of the German multicenter phase II trial (ARO-2010-01)

PURPOSE

To evaluate the feasibility of hypofractionation with SIB in all settings in Germany to prepare a multicenter treatment comparison.

METHODS

Eligible patients had histopathologically confirmed breast cancer operated by BCS. Patients received WBI 40.0 Gy in 16 fractions of 2.5 Gy. A SIB with 0.5 Gy per fraction was administered to the tumor bed, thereby giving 48.0 Gy in 16 fractions to the boost-PTV sparing heart, LAD, lung, contralateral breast. The primary study objective was feasibility, administration of specified dose in 16 fractions within 22-29 days with adherence to certain dose constraints (heart; LAD; contralateral breast); secondary endpoints were toxicity, QoL.

RESULTS

151 patients were recruited from 7 institutions between 07/11-10/12. 10 patients met exclusion criteria prior to irradiation. All but two patients (99%) received the prescribed dose in the PTVs. Adherence to dose constraints and time limits was achieved in 89% (95% CI 82% to 93%). 11 AE were reported in 10 patients; five related to concurrent endocrine therapy. Two of the AEs were related to radiotherapy: grade 3 hot flushes in two cases. QoL remained unchanged.

CONCLUSION

Hypofractionation with a SIB is feasible and was well tolerated in this study.

[Breast ductal carcinoma in situ with microinvasion: pathological review and clinical implications]

PURPOSE

Recent improvements in the detection of breast cancer at an early stage have resulted in a rising incidence of breast ductal carcinoma in situ with microinvasion. So far, there is no consensus regarding its optimal management. We hereby report on our 10-year single institutional experience in breast ductal carcinoma in situ with microinvasion including pathological reviewing.

PATIENTS AND METHODS

All consecutive patients treated for a ductal carcinoma in situ with microinvasion at the Institut Claudius-Regaud (Toulouse, France) over a 10-year period were included in this study. We reviewed all available histological materials.

RESULTS

Sixty-three patients were eligible for this study. Two patients presented with a lymph node invasion at diagnosis. Each patient benefited from initial surgical management, which consisted either in mastectomy (n=25) or conservative resection (n=37). Axillary exploration was performed in 52 patients (82%). After a median follow-up of 61.3 months [46.9;69], the 5-year overall survival and disease free survival were 98.2 (95% CI=[88.2;99.7]) and 89.5% (95% CI=[76.3;95.6]) respectively. Two delayed invasive relapses occurred leading to one specific death. The pathological review highlighted a trend towards a loss of HR and HER2 expression (9%) in the microinvasive component in comparison with its surrounded in situ carcinoma.

CONCLUSION

The risk of initial lymph node involvement and delayed invasive local relapse deserve an optimal locoregional management including lymph node evaluation. The non-negligible discrepancy's rate between in situ and microinvasive components justifies HR status and HER2 expression assessment on the microinvasive component.

Radiotherapy after conservative surgery in ductal carcinoma in situ of the breast: a review

Several large prospective and retrospective studies have demonstrated excellent long-term outcomes after breast conservative treatment with radiation in invasive breast cancer. Breast-conserving surgery (BCS) followed by radiotherapy (RT) is an accepted management strategy for patients with DCIS. Adding radiation treatment after conservative surgery enables to reduce, without any significant risks, the rate of local recurrence (LR) by approximately 50% in retrospective and randomized clinical trials. As about 50% of LRs are invasive and have a negative psychological impact, minimizing recurrence is important. Local and local-regional recurrences after initial breast conservation treatment with radiation can be salvaged with high rates of survival and freedom from distant metastases.

Role of the radiotherapy boost on local control in ductal carcinoma in situ

Ductal carcinoma in situ of the breast is associated with low mortality rates, but local relapse is a matter of concern in this disease. Risk factors for local relapse include young age, close or positive margins, and tumor necrosis. Whole breast irradiation following breast-conserving surgery for ductal carcinoma in situ significantly reduces the risk of local relapse as compared to breast-conserving surgery alone. Studies point to similar outcomes between breast-conserving surgery plus radiotherapy and mastectomy, in the absence of extensive disease. A complementary boost to the surgical bed improves outcomes for patients with invasive breast cancer. However, the effect of this strategy has never been prospectively reported for ductal carcinoma in situ. Two randomized controlled trials assessing this issue are ongoing. This paper represents an update on available literature about radiotherapy for DCIS with a special focus on the role of a radiotherapy boost to the tumor bed.

The management of ductal intraepithelial neoplasia (DIN): open controversies and guidelines of the Istituto Europeo di Oncologia (IEO), Milan, Italy

The management of ductal intraepithelial neoplasia (DIN) has substantially changed over the past 30 years, as its incidence has increased (from 2-3% to more than 20%), mainly due to the widespread use of mammography screening. This article describes not only the more widespread theoretical concepts on DIN but also the differences in the practical applications of the theory between different countries, different oncology specialists, and different cancer centers. Papers related to the international multicentre-randomized trials and retrospective studies were analyzed. We include articles and papers published between 1993 and 2010 related to patients with DIN, and abstracts and reports from MEDLINE and other sources were indentified. The standard of care for DIN consists of (a) breast conservative surgery (mastectomy is still indicated in large lesions--masses or microcalcifications--in about 30% of cases); (b) radiotherapy (RT) after conservative surgery, and (c) medical treatment in estrogen receptors-positive patients. However, most studies have shown significant differences between theory and practical application. Moreover, there are differences regarding (a) the indications of sentinel lymph node biopsy, (b) the definition and identification of low-risk DIN subgroups that can avoid RT and tamoxifen, and (c) the research into new alternative drugs in adjuvant medical therapy. A general agreement on the best management of DIN does not exist as yet. New large trials are needed in order to define the best management of DIN patients which is (in most respects) still complex and controversial.