Postoperative radiotherapy omission in selected patients with early breast cancer following preoperative breast MRI (PROSPECT): primary results of a prospective two-arm study.

BACKGROUND: Adjuvant breast radiotherapy as a standard component of breast-conserving treatment for early cancer can overtreat many women. Breast MRI is the most sensitive modality to assess local tumour burden. The aim of this study was to determine whether a combination of MRI and pathology findings can identify women with truly localised breast cancer who can safely avoid radiotherapy. METHODS: PROSPECT is a prospective, multicentre, two-arm, non-randomised trial of radiotherapy omission in patients selected using preoperative MRI and postoperative tumour pathology. It is being conducted at four academic hospitals in Australia. Women aged 50 years or older with cT1N0 non-triple-negative breast cancer were eligible. Those with apparently unifocal cancer had breast-conserving surgery (BCS) and, if pT1N0 or N1mi, had radiotherapy omitted (group 1). Standard treatment including excision of MRI-detected additional cancers was offered to the others (group 2). All were recommended systemic therapy. The primary outcome was ipsilateral invasive recurrence rate (IIRR) at 5 years in group 1. Primary analysis occurred after the 100th group 1 patient reached 5 years follow-up. Quality-adjusted life-years (QALYs) and cost-effectiveness of the PROSPECT pathway were analysed. This study is registered with the Australian New Zealand Clinical Trials Registry (ACTRN12610000810011). FINDINGS: Between May 17, 2011, and May 6, 2019, 443 patients with breast cancer underwent MRI. Median age was 63·0 years. MRI detected 61 malignant occult lesions separate from the index cancer in 48 patients (11%). Of 201 group 1 patients who had BCS without radiotherapy, the IIRR at 5 years was 1·0% (upper 95% CI 5·4%). In group 1, one local recurrence occurred at 4·5 years and a second at 7·5 years. In group 2, nine patients had mastectomy (2% of total cohort), and the 5-year IIRR was 1·7% (upper 95% CI 6·1%). The only distant metastasis in the entire cohort was genetically distinct from the index cancer. The PROSPECT pathway increased QALYs by 0·019 (95% CI 0·008-0·029) and saved AU$1980 (95% CI 1396-2528) or £953 (672-1216) per patient. INTERPRETATION: PROSPECT suggests that women with unifocal breast cancer on MRI and favourable pathology can safely omit radiotherapy. FUNDING: Breast Cancer Trials, National Breast Cancer Foundation, Cancer Council Victoria, the Royal Melbourne Hospital Foundation, and the Breast Cancer Research Foundation.

Is de-escalation of treatment by omission of radiotherapy associated with fear of cancer recurrence in women with early breast cancer? An exploratory study.

PURPOSE: Safe de-intensification of adjuvant radiotherapy (RT) for early breast cancer (BC) is currently under evaluation. Little is known about the patient experience of de-escalation or its association with fear of cancer recurrence (FCR), a key issue in survivorship. We conducted a cross-sectional study to explore this association. METHODS: Psychometrically validated measures including the Fear of Cancer Recurrence Inventory-Short Form were completed by three groups of women with early BC: Women in the PROSPECT clinical trial who underwent pre-surgical MRI and omitted RT (A), women who underwent pre-surgical MRI and received RT (B); and women who received usual care (no MRI, received RT; C). Between group differences were analysed with non-parametric tests. A subset from each group participated in a semi-structured interview. These data (n = 44) were analysed with directed content analysis. RESULTS: Questionnaires from 400 women were analysed. Significantly lower FCR was observed in Group A (n = 125) than in Group B (n = 102; p = .002) or Group C (n = 173; p = .001), and when participants were categorized by RT status (omitted RT vs received RT; p < .001). The proportion of women with normal FCR was significantly (p < .05) larger in Group A (62%) than in Group B (35%) or Group C (40%). Two qualitative themes emerged: 'What I had was best' and 'Coping with FCR'. CONCLUSIONS: Omitting RT in the setting of the PROSPECT trial was not associated with higher FCR than receiving RT. Positive perceptions about tailored care, lower treatment burden, and trust in clinicians appear to be protective against FCR.

Quality of Life Outcomes Associated With Optimization of Treatment by Omitting Radiotherapy in Early Breast Cancer.

PURPOSE: Improved prognosis of early breast cancer (EBC) has created opportunities for treatment optimization but reducing morbidity should not inadvertently compromise quality of life (QoL). PROSPECT1 used pre-operative MRI and pathology findings to identify women suitable for radiotherapy (RT) omission following breast conserving surgery. We retrospectively explored the association between de-escalation by omission of RT and QoL in women with EBC. MATERIALS AND METHODS: Three groups were recruited: PROSPECT participants who omitted RT following preoperative MRI (A); participants who received RT following preoperative MRI (B); and women who received usual care - No MRI, received RT (C). Measures included the EORTC QLQ-C30 and BR23, BCTOS, DASS-21 and a measure of decision regret. Between group differences were assessed using ANOVA or nonparametric equivalents. Semi-structured interviews were analyzed with qualitative description (n = 44). RESULTS: Data from 400 women were analyzed (125A, 102B, 173C). Group A had fewer symptoms and better body image (breast symptoms: A-B P = .003, A-C P = <.001; arm symptoms: A-B P = .004, A-C P = .011; body image: A-C P = .041) and fewer differences between the treated and untreated breasts (cosmetic: A-B P < .001, A-C P < .001; functional: A-C P = .011; breast specific pain: A-B P < .001, A-C P < .001). Two qualitative themes were found: Treatment with the biggest impact on QoL, and Specific impact of RT on QoL. CONCLUSIONS: Omission of RT was associated with better QoL and functional and cosmetic outcomes. It was highly acceptable to patients. Clinicians should consider the potential for preserved QoL associated with treatment optimization via omission of RT in treatment planning for patients with EBC.