Omitting Radiotherapy after Breast-Conserving Surgery in Luminal A Breast Cancer.

BACKGROUND: Adjuvant radiotherapy is prescribed after breast-conserving surgery to reduce the risk of local recurrence. However, radiotherapy is inconvenient, costly, and associated with both short-term and long-term side effects. Clinicopathologic factors alone are of limited use in the identification of women at low risk for local recurrence in whom radiotherapy can be omitted. Molecularly defined intrinsic subtypes of breast cancer can provide additional prognostic information. METHODS: We performed a prospective cohort study involving women who were at least 55 years of age, had undergone breast-conserving surgery for T1N0 (tumor size <2 cm and node negative), grade 1 or 2, luminal A-subtype breast cancer (defined as estrogen receptor positivity of ≥1%, progesterone receptor positivity of >20%, negative human epidermal growth factor receptor 2, and Ki67 index of ≤13.25%), and had received adjuvant endocrine therapy. Patients who met the clinical eligibility criteria were registered, and Ki67 immunohistochemical analysis was performed centrally. Patients with a Ki67 index of 13.25% or less were enrolled and did not receive radiotherapy. The primary outcome was local recurrence in the ipsilateral breast. In consultation with radiation oncologists and patients with breast cancer, we determined that if the upper boundary of the two-sided 90% confidence interval for the cumulative incidence at 5 years was less than 5%, this would represent an acceptable risk of local recurrence at 5 years. RESULTS: Of 740 registered patients, 500 eligible patients were enrolled. At 5 years after enrollment, recurrence was reported in 2.3% of the patients (90% confidence interval [CI], 1.3 to 3.8; 95% CI, 1.2 to 4.1), a result that met the prespecified boundary. Breast cancer occurred in the contralateral breast in 1.9% of the patients (90% CI, 1.1 to 3.2), and recurrence of any type was observed in 2.7% (90% CI, 1.6 to 4.1). CONCLUSIONS: Among women who were at least 55 years of age and had T1N0, grade 1 or 2, luminal A breast cancer that were treated with breast-conserving surgery and endocrine therapy alone, the incidence of local recurrence at 5 years was low with the omission of radiotherapy. (Funded by the Canadian Cancer Society and the Canadian Breast Cancer Foundation; LUMINA ClinicalTrials.gov number, NCT01791829.).

Long-term outcomes and effects of hypofractionated radiotherapy in microinvasive breast cancer: Analysis from a randomized trial.

PURPOSE: The natural history of microinvasive (T1mi) breast cancer is uncertain. The objective was to evaluate long-term local and distant recurrence rates following breast conserving surgery (BCS) in a prospective cohort of patients with T1mi compared to T1a-2 disease who received whole breast irradiation (WBI) in the context of a randomized trial of hypofractionation. METHODS: 1234 patients with T1-2 N0 breast cancer were randomized to receive adjuvant WBI of 42.5Gy in 16 daily fractions, or 50Gy in 25 daily fractions after BCS. An analysis of patients with T1mi tumors compared with T1a-2 disease was performed. Kaplan-Meier estimates of local recurrence (LR), distant recurrence, and overall survival (OS) were compared using the log-rank test. RESULTS: Median follow-up was 12 years. T1mi was found in 3% (n = 38) of patients. The 10-year LR rate was 22.6% in T1mi vs. 6.9% in T1a-2 breast cancer [hazard ratio (HR) = 3.73; 95% confidence interval (CI): 1.93, 7.19; p < 0.001]. The 10-year risk of distant recurrence was 5.1% for T1mi, and 12.1% for T1a-2 disease (HR = 0.56; 95% CI: 0.19, 1.84; p = 0.36). Ten-year OS was 91.5% in T1mi and 84.4% in T1a-2 disease, (HR = 0.48; 95% CI: 0.18, 1.30; p = 0.14). Rates of LR did not differ whether treated by hypofractionation or conventional fractionation (HR = 1.21; 95% CI: 0.35, 4.18; p = 0.77). CONCLUSIONS: The risk of LR was considerably higher in patients with T1mi compared to T1a-2 tumors, but OS remained very good. Future research should evaluate the utility of wider local excision and boost radiation to optimize local control for microinvasive breast cancer.

Sequencing of Androgen-Deprivation Therapy With External-Beam Radiotherapy in Localized Prostate Cancer: A Phase III Randomized Controlled Trial.

PURPOSE: Dose-escalated radiotherapy (RT) with androgen-deprivation therapy (ADT) is a standard definitive treatment of localized prostate cancer (LPCa). The optimal sequencing of these therapies is unclear. Our phase III trial compared neoadjuvant versus concurrent initiation of ADT in combination with dose-escalated prostate RT (PRT). PATIENTS AND METHODS: Patients with newly diagnosed LPCa with Gleason score ≤ 7, clinical stage T1b to T3a, and prostate-specific antigen < 30 ng/mL were randomly allocated to neoadjuvant and concurrent ADT for 6 months starting 4 months before RT (neoadjuvant group) or concurrent and adjuvant ADT for 6 months starting simultaneously with RT (concurrent group). The primary end point was biochemical relapse-free survival (bRFS). Stratified log-rank test was used to compare bRFS and overall survival (OS). Incidence of grade ≥ 3 late RT-related toxicities was compared by log-rank test. RESULTS: Overall, 432 patients were randomly assigned to the neoadjuvant (n = 215) or concurrent group (n = 217). At 10 years, bRFS rates for the two groups were 80.5% and 87.4%, respectively. Ten-year OS rates were 76.4% and 73.7%, respectively. There was no significant difference in bRFS (P = .10) or OS (P = .70) between the two groups. Relative to the neoadjuvant group, the hazard ratio for the concurrent group was 0.66 (95% CI, 0.41 to 1.07) for bRFS and 0.94 (95% CI, 0.68 to 1.30) for OS. No significant difference was observed in the 3-year incidence of late RT-related grade ≥ 3 GI (2.5% v 3.9%) or genitourinary toxicity (2.9% v 2.9%). CONCLUSION: In our study, there was no statistically significant difference in bRFS between the two treatment groups. Similarly, no difference was seen in OS or late RT-related toxicities. On the basis of these results, both neoadjuvant and concurrent initiations of short-term ADT with dose-escalated PRT are reasonable standards of care for LPCa.

Regional Nodal Irradiation in Early-Stage Breast Cancer.

BACKGROUND: Most women with breast cancer who undergo breast-conserving surgery receive whole-breast irradiation. We examined whether the addition of regional nodal irradiation to whole-breast irradiation improved outcomes. METHODS: We randomly assigned women with node-positive or high-risk node-negative breast cancer who were treated with breast-conserving surgery and adjuvant systemic therapy to undergo either whole-breast irradiation plus regional nodal irradiation (including internal mammary, supraclavicular, and axillary lymph nodes) (nodal-irradiation group) or whole-breast irradiation alone (control group). The primary outcome was overall survival. Secondary outcomes were disease-free survival, isolated locoregional disease-free survival, and distant disease-free survival. RESULTS: Between March 2000 and February 2007, a total of 1832 women were assigned to the nodal-irradiation group or the control group (916 women in each group). The median follow-up was 9.5 years. At the 10-year follow-up, there was no significant between-group difference in survival, with a rate of 82.8% in the nodal-irradiation group and 81.8% in the control group (hazard ratio, 0.91; 95% confidence interval [CI], 0.72 to 1.13; P=0.38). The rates of disease-free survival were 82.0% in the nodal-irradiation group and 77.0% in the control group (hazard ratio, 0.76; 95% CI, 0.61 to 0.94; P=0.01). Patients in the nodal-irradiation group had higher rates of grade 2 or greater acute pneumonitis (1.2% vs. 0.2%, P=0.01) and lymphedema (8.4% vs. 4.5%, P=0.001). CONCLUSIONS: Among women with node-positive or high-risk node-negative breast cancer, the addition of regional nodal irradiation to whole-breast irradiation did not improve overall survival but reduced the rate of breast-cancer recurrence. (Funded by the Canadian Cancer Society Research Institute and others; MA.20 ClinicalTrials.gov number, NCT00005957.).

Long-term results of hypofractionated radiation therapy for breast cancer.

BACKGROUND: The optimal fractionation schedule for whole-breast irradiation after breast-conserving surgery is unknown. METHODS: We conducted a study to determine whether a hypofractionated 3-week schedule of whole-breast irradiation is as effective as a 5-week schedule. Women with invasive breast cancer who had undergone breast-conserving surgery and in whom resection margins were clear and axillary lymph nodes were negative were randomly assigned to receive whole-breast irradiation either at a standard dose of 50.0 Gy in 25 fractions over a period of 35 days (the control group) or at a dose of 42.5 Gy in 16 fractions over a period of 22 days (the hypofractionated-radiation group). RESULTS: The risk of local recurrence at 10 years was 6.7% among the 612 women assigned to standard irradiation as compared with 6.2% among the 622 women assigned to the hypofractionated regimen (absolute difference, 0.5 percentage points; 95% confidence interval [CI], -2.5 to 3.5). At 10 years, 71.3% of women in the control group as compared with 69.8% of the women in the hypofractionated-radiation group had a good or excellent cosmetic outcome (absolute difference, 1.5 percentage points; 95% CI, -6.9 to 9.8). CONCLUSIONS: Ten years after treatment, accelerated, hypofractionated whole-breast irradiation was not inferior to standard radiation treatment in women who had undergone breast-conserving surgery for invasive breast cancer with clear surgical margins and negative axillary nodes. (ClinicalTrials.gov number, NCT00156052.)

Is biochemical response more important than duration of neoadjuvant hormone therapy before radiotherapy for clinically localized prostate cancer? An analysis of the 3- versus 8-month randomized trial.

PURPOSE: To ascertain whether biochemical response to neoadjuvant androgen-deprivation therapy (ADT) before radiotherapy (RT), rather than duration, is the critical determinant of benefit in the multimodal treatment of localized prostate cancer, by comparing outcomes of subjects from the Canadian multicenter 3- vs 8-month trial with a pre-RT, post-hormone PSA (PRPH-PSA) < or =0.1 ng/ml vs those >0.1 ng/ml. METHODS AND MATERIALS: From 1995 to 2001, 378 men with localized prostate cancer were randomized to 3 or 8 months of neoadjuvant ADT before RT. On univariate analysis, survival indices were compared between those with a PRPH-PSA < or =0.1 ng/ml vs >0.1 ng/ml, for all patients and subgroups, including treatment arm, risk group, and gleason Score. Multivariate analysis identified independent predictors of outcome. RESULTS: Biochemical disease-free survival (bDFS) was significantly higher for those with a PRPH-PSA < or =0.1 ng/ml compared with PRPH-PSA >0.1 ng/ml (55.3% vs 49.4%, p = 0.014). No difference in survival indices was observed between treatment arms. There was no difference in bDFS between patients in the 3- and 8-month arms with a PRPH-PSA < or =0.1 ng/ml nor those with PRPH-PSA >0.1 ng/ml. bDFS was significantly higher for high-risk patients with PRPH-PSA < or =0.1 ng/ml compared with PRPH-PSA >0.1 ng/ml (57.0% vs 29.4%, p = 0.017). Multivariate analysis identified PRPH-PSA (p = 0.041), Gleason score (p = 0.001), initial PSA (p = 0.025), and T-stage (p = 0.003), not ADT duration, as independent predictors of outcome. CONCLUSION: Biochemical response to neoadjuvant ADT before RT, not duration, appears to be the critical determinant of benefit in the setting of combined therapy. Individually tailored ADT duration based on PRPH-PSA would maximize therapeutic gain, while minimizing the duration of ADT and its related toxicities.

Final report of multicenter Canadian Phase III randomized trial of 3 versus 8 months of neoadjuvant androgen deprivation therapy before conventional-dose radiotherapy for clinically localized prostate cancer.

PURPOSE: To evaluate the effect of 3 vs. 8 months of neoadjuvant hormonal therapy before conventional-dose radiotherapy (RT) on disease-free survival for localized prostate cancer. METHODS AND MATERIALS: Between February 1995 and June 2001, 378 men were randomized to either 3 or 8 months of flutamide and goserelin before 66 Gy RT at four participating centers. The median baseline prostate-specific antigen level was 9.7 ng/mL (range, 1.3-189). Of the 378 men, 26% had low-, 43% intermediate-, and 31% high-risk disease. The two arms were balanced in terms of age, Gleason score, clinical T category, risk group, and presenting prostate-specific antigen level. The median follow-up for living patients was 6.6 years (range, 1.6-10.1). Of the 378 patients, 361 were evaluable, and 290 were still living. RESULTS: The 5-year actuarial freedom from failure rate for the 3- vs. 8-month arms was 72% vs. 75%, respectively (p = 0.18). No difference was found in the failure types between the two arms. The median prostate-specific antigen level at the last follow-up visit for patients without treatment failure was 0.6 ng/mL in the 3-month arm vs. 0.50 ng/mL in the 8-month arm. The disease-free survival rate at 5 years was improved for the high-risk patients in the 8-month arm (71% vs. 42%, p = 0.01). CONCLUSION: A longer period of NHT before standard-dose RT did not alter the patterns of failure when combined with 66-Gy RT. High-risk patients in the 8-month arm had significant improvement in the 5-year disease-free survival rate.

Report of a multicenter Canadian phase III randomized trial of 3 months vs. 8 months neoadjuvant androgen deprivation before standard-dose radiotherapy for clinically localized prostate cancer.

PURPOSE: To evaluate the effect of 3 months vs. 8 months of neoadjuvant hormonal therapy before conventional dose radiotherapy (RT) on disease-free survival using prostate-specific antigen PSA and biopsies as end points for clinically localized prostate cancer. METHODS AND MATERIALS: Between February 1995 and June 2001, 378 men were randomized to either 3 or 8 months of flutamide and goserelin before conventional-dose RT (66 Gy) at four participating centers. The median patient age was 72 years (range, 50-84 years). The stage distribution was 17% T1c, 35% T2a, 34% T2b-T2c, 13% T3-T4. The Gleason score (GS) was < or =6 in 51%, 7 in 38%, and 8-10 in 11%. The median baseline PSA level was 9.7 ng/mL (range, 1.3-189 ng/mL). Of the 378 men, 26% were low risk (Stage T1c-T2a, GS < or =6, PSA <10 ng/mL), 43% were intermediate risk (Stage T2b or GS 7 or PSA 10-20 ng/mL), and 31% were high risk (Stage T3 or GS 8-10 or PSA >20 ng/mL). The two arms were balanced in terms of age, GS, T stage, risk group, and presenting PSA level. The median follow-up was 44 months (range, 10-84 months), and 361 patients were available for evaluation. RESULTS: The 8-month arm achieved a lower PSA level before starting RT (0.37 vs. 0.74 ng/mL, p < or =0.001) and had a greater downsizing of the prostate (mean volume 26.6 cm(3) vs. 30.5 cm(3), p < or =0.001). However, the actuarial freedom from failure rate (biochemical by American Society for Therapeutic Radiology and Oncology definition, local or distant) for the 3-month vs. 8-month arms at 3 years was 66% vs. 68% and by 5 years was 61% vs. 62%, respectively (p = 0.36). No statistically significant difference was noted in the types of failure between the two arms (crude final status): biochemical, 22.2% vs. 22.3%; local, 10.2% vs. 6.5%; and distant, 3.4% vs. 4.4% (p = 0.61). Two-year post-RT biopsies were done in 57% (n = 205). Negative biopsies were obtained in 68% of the 3-month and 77% of the 8-month patients; 18% and 14% had indeterminate biopsies and 14% and 9% were positive for residual cancer (p = 0.34) in the two arms, respectively. The median PSA level for nonfailing patients was 0.50 ng/mL in both the 3-months and 8-month arms. A suggestion of improvement was found in the 8-month arm for disease-free survival at 5 years for high-risk patients (39% vs. 52%) but did not achieve statistical significance. CONCLUSION: A longer period of neoadjuvant hormonal therapy before standard-dose RT does not appear to confer a benefit in terms of disease-free survival or to alter failure patterns. Failure was delayed in the 8-month arm, but this advantage was lost by 5 years of follow-up. A suggestion of benefit was noted with a longer period of hormonal therapy for high-risk patients.