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SAN FRANCISCO – Ten years of follow-up showed no significant difference in breast cancer locoregional recurrence, distant metastasis, or survival rates in 274 patients treated with accelerated partial breast irradiation compared with 274 matched patients treated with whole breast irradiation.
The data came from records on 3,009 patients with early-stage breast cancer who were treated with breast-conserving therapy at one institution between 1980 and 2012.
Four percent in each group developed local recurrence, 1% in each group had a regional recurrence, and 6% had distant metastases after partial breast irradiation and 3%, after whole breast irradiation. There was a nonsignificant statistical trend toward a higher rate of contralateral breast failure in the whole breast irradiation group (9%) compared with the partial breast irradiation group (3%, P = .06), Dr. Jessica Wobb reported in a poster presentation at a breast cancer symposium sponsored by the American Society of Clinical Oncology.
Rates of disease-free survival were 91% in the partial breast irradiation group and 93% in the whole breast irradiation group. Cause-specific survival rates were 93% and 94%, respectively, and overall survival rates were 75% and 82%, reported Dr. Wobb of the Beaumont Cancer Institute, Royal Oak, Mich. None of these differences reached statistical significance.
This is one of the first reports on prolonged follow-up after accelerated partial breast irradiation, she noted. Mean follow-up was 7.8 years after partial breast irradiation and 8.1 years after whole breast irradiation, a difference that was statistically significant, but amounted to less than 4 months. All patients were followed for at least 1 year.
Patients in the cohorts were matched by age (within 3 years); T stage (Tis, T1, or T2); and estrogen receptor (ER) status. The mean age was 63 years of age in both groups. Eighty-eight percent in both groups had ER-positive tumors. The stage distribution in both groups consisted of 18% with stage Tis tumors, 71% with T1 tumors, and 11% with T2 tumors.
Significantly fewer patients in the partial breast irradiation group received adjuvant hormonal therapy (54%) compared with those in the whole breast irradiation group (68%). There was a trend toward smaller tumors in patients undergoing partial breast irradiation than in those receiving whole breast irradiation, with mean tumor sizes of 11.4 mm and 13 mm (P = .06).
Other characteristics were similar between the groups, including the proportion with negative lymph nodes (91% of patients undergoing partial breast irradiation and 86% of those who got whole breast irradiation), the proportion with negative final margins (94% and 95%, respectively), and the proportion who received adjuvant chemotherapy (15% and 18%).
Close tumor margins increased the risk for ipsilateral breast tumor recurrence in both groups, and positive margins increased the recurrence risk in the whole breast irradiation group, a univariate analysis found.
Dr. Wobb reported having no relevant financial disclosures.
On Twitter @sherryboschert
In the absence of prospective, randomized trial data on accelerated partial breast irradiation to guide us, we are left with the accumulation of institutional data. The institution that, in my opinion, has contributed most to our knowledge base is the group at William Beaumont Hospital. We’re fortunate to have an update of their experience in that they’ve performed an updated a matched-pair analysis looking at their partial breast irradiation patients (using interstitial catheter or balloon-based brachytherapy two different techniques), compared with their whole breast irradiation patients.
In this matched-pair comparison, the investigators saw no difference in local failure, regional failure, distant metastases, or overall survival.
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Of course, we have to ask, in a matched pair, how good is the match? We do notice that in their group it’s a pretty good match, but we see that for whole breast irradiation, there are slightly larger tumors in that cohort and slightly more positive-node patients. Perhaps the most unsettling aspect is that there is more hormonal therapy in the whole breast irradiation group. This could reflect two things: One is an imbalance in prognostic factors between the two cohorts; the other is an impact of hormonal therapy on local and regional control outcomes.
When we look at their results related to clinical variables and outcome, not surprisingly we find that a negative margin is always better irrespective of whether the patient is getting whole breast irradiation or partial breast irradiation. Interestingly, in the partial breast irradiation group, younger age was associated with a higher risk of local failure.
What’s missing from this analysis? Again, this is not a fault of the investigators; just by virtue of this being a retrospective collection of data, it’s sometimes hard to get all this data. The questions that I think are pertinent in 2013 relate to grade, triple-negative phenotype versus other phenotypes, human epidermal growth factor receptor 2 status, and lymphatic vascular invasion. Unfortunately, none of that information is present in this analysis.
Dr. David E. Wazer is a professor of radiation oncology at Brown University, Providence, R.I. These are excerpts of his remarks as the discussant of Dr. Wobb’s study at the meeting. Dr. Wazer reported financial associations with the American Brachytherapy Society, Advanced Radiation Therapy, and American Journal of Clinical Oncology.
In the absence of prospective, randomized trial data on accelerated partial breast irradiation to guide us, we are left with the accumulation of institutional data. The institution that, in my opinion, has contributed most to our knowledge base is the group at William Beaumont Hospital. We’re fortunate to have an update of their experience in that they’ve performed an updated a matched-pair analysis looking at their partial breast irradiation patients (using interstitial catheter or balloon-based brachytherapy two different techniques), compared with their whole breast irradiation patients.
In this matched-pair comparison, the investigators saw no difference in local failure, regional failure, distant metastases, or overall survival.
|
|
Of course, we have to ask, in a matched pair, how good is the match? We do notice that in their group it’s a pretty good match, but we see that for whole breast irradiation, there are slightly larger tumors in that cohort and slightly more positive-node patients. Perhaps the most unsettling aspect is that there is more hormonal therapy in the whole breast irradiation group. This could reflect two things: One is an imbalance in prognostic factors between the two cohorts; the other is an impact of hormonal therapy on local and regional control outcomes.
When we look at their results related to clinical variables and outcome, not surprisingly we find that a negative margin is always better irrespective of whether the patient is getting whole breast irradiation or partial breast irradiation. Interestingly, in the partial breast irradiation group, younger age was associated with a higher risk of local failure.
What’s missing from this analysis? Again, this is not a fault of the investigators; just by virtue of this being a retrospective collection of data, it’s sometimes hard to get all this data. The questions that I think are pertinent in 2013 relate to grade, triple-negative phenotype versus other phenotypes, human epidermal growth factor receptor 2 status, and lymphatic vascular invasion. Unfortunately, none of that information is present in this analysis.
Dr. David E. Wazer is a professor of radiation oncology at Brown University, Providence, R.I. These are excerpts of his remarks as the discussant of Dr. Wobb’s study at the meeting. Dr. Wazer reported financial associations with the American Brachytherapy Society, Advanced Radiation Therapy, and American Journal of Clinical Oncology.
In the absence of prospective, randomized trial data on accelerated partial breast irradiation to guide us, we are left with the accumulation of institutional data. The institution that, in my opinion, has contributed most to our knowledge base is the group at William Beaumont Hospital. We’re fortunate to have an update of their experience in that they’ve performed an updated a matched-pair analysis looking at their partial breast irradiation patients (using interstitial catheter or balloon-based brachytherapy two different techniques), compared with their whole breast irradiation patients.
In this matched-pair comparison, the investigators saw no difference in local failure, regional failure, distant metastases, or overall survival.
|
|
Of course, we have to ask, in a matched pair, how good is the match? We do notice that in their group it’s a pretty good match, but we see that for whole breast irradiation, there are slightly larger tumors in that cohort and slightly more positive-node patients. Perhaps the most unsettling aspect is that there is more hormonal therapy in the whole breast irradiation group. This could reflect two things: One is an imbalance in prognostic factors between the two cohorts; the other is an impact of hormonal therapy on local and regional control outcomes.
When we look at their results related to clinical variables and outcome, not surprisingly we find that a negative margin is always better irrespective of whether the patient is getting whole breast irradiation or partial breast irradiation. Interestingly, in the partial breast irradiation group, younger age was associated with a higher risk of local failure.
What’s missing from this analysis? Again, this is not a fault of the investigators; just by virtue of this being a retrospective collection of data, it’s sometimes hard to get all this data. The questions that I think are pertinent in 2013 relate to grade, triple-negative phenotype versus other phenotypes, human epidermal growth factor receptor 2 status, and lymphatic vascular invasion. Unfortunately, none of that information is present in this analysis.
Dr. David E. Wazer is a professor of radiation oncology at Brown University, Providence, R.I. These are excerpts of his remarks as the discussant of Dr. Wobb’s study at the meeting. Dr. Wazer reported financial associations with the American Brachytherapy Society, Advanced Radiation Therapy, and American Journal of Clinical Oncology.
SAN FRANCISCO – Ten years of follow-up showed no significant difference in breast cancer locoregional recurrence, distant metastasis, or survival rates in 274 patients treated with accelerated partial breast irradiation compared with 274 matched patients treated with whole breast irradiation.
The data came from records on 3,009 patients with early-stage breast cancer who were treated with breast-conserving therapy at one institution between 1980 and 2012.
Four percent in each group developed local recurrence, 1% in each group had a regional recurrence, and 6% had distant metastases after partial breast irradiation and 3%, after whole breast irradiation. There was a nonsignificant statistical trend toward a higher rate of contralateral breast failure in the whole breast irradiation group (9%) compared with the partial breast irradiation group (3%, P = .06), Dr. Jessica Wobb reported in a poster presentation at a breast cancer symposium sponsored by the American Society of Clinical Oncology.
Rates of disease-free survival were 91% in the partial breast irradiation group and 93% in the whole breast irradiation group. Cause-specific survival rates were 93% and 94%, respectively, and overall survival rates were 75% and 82%, reported Dr. Wobb of the Beaumont Cancer Institute, Royal Oak, Mich. None of these differences reached statistical significance.
This is one of the first reports on prolonged follow-up after accelerated partial breast irradiation, she noted. Mean follow-up was 7.8 years after partial breast irradiation and 8.1 years after whole breast irradiation, a difference that was statistically significant, but amounted to less than 4 months. All patients were followed for at least 1 year.
Patients in the cohorts were matched by age (within 3 years); T stage (Tis, T1, or T2); and estrogen receptor (ER) status. The mean age was 63 years of age in both groups. Eighty-eight percent in both groups had ER-positive tumors. The stage distribution in both groups consisted of 18% with stage Tis tumors, 71% with T1 tumors, and 11% with T2 tumors.
Significantly fewer patients in the partial breast irradiation group received adjuvant hormonal therapy (54%) compared with those in the whole breast irradiation group (68%). There was a trend toward smaller tumors in patients undergoing partial breast irradiation than in those receiving whole breast irradiation, with mean tumor sizes of 11.4 mm and 13 mm (P = .06).
Other characteristics were similar between the groups, including the proportion with negative lymph nodes (91% of patients undergoing partial breast irradiation and 86% of those who got whole breast irradiation), the proportion with negative final margins (94% and 95%, respectively), and the proportion who received adjuvant chemotherapy (15% and 18%).
Close tumor margins increased the risk for ipsilateral breast tumor recurrence in both groups, and positive margins increased the recurrence risk in the whole breast irradiation group, a univariate analysis found.
Dr. Wobb reported having no relevant financial disclosures.
On Twitter @sherryboschert
SAN FRANCISCO – Ten years of follow-up showed no significant difference in breast cancer locoregional recurrence, distant metastasis, or survival rates in 274 patients treated with accelerated partial breast irradiation compared with 274 matched patients treated with whole breast irradiation.
The data came from records on 3,009 patients with early-stage breast cancer who were treated with breast-conserving therapy at one institution between 1980 and 2012.
Four percent in each group developed local recurrence, 1% in each group had a regional recurrence, and 6% had distant metastases after partial breast irradiation and 3%, after whole breast irradiation. There was a nonsignificant statistical trend toward a higher rate of contralateral breast failure in the whole breast irradiation group (9%) compared with the partial breast irradiation group (3%, P = .06), Dr. Jessica Wobb reported in a poster presentation at a breast cancer symposium sponsored by the American Society of Clinical Oncology.
Rates of disease-free survival were 91% in the partial breast irradiation group and 93% in the whole breast irradiation group. Cause-specific survival rates were 93% and 94%, respectively, and overall survival rates were 75% and 82%, reported Dr. Wobb of the Beaumont Cancer Institute, Royal Oak, Mich. None of these differences reached statistical significance.
This is one of the first reports on prolonged follow-up after accelerated partial breast irradiation, she noted. Mean follow-up was 7.8 years after partial breast irradiation and 8.1 years after whole breast irradiation, a difference that was statistically significant, but amounted to less than 4 months. All patients were followed for at least 1 year.
Patients in the cohorts were matched by age (within 3 years); T stage (Tis, T1, or T2); and estrogen receptor (ER) status. The mean age was 63 years of age in both groups. Eighty-eight percent in both groups had ER-positive tumors. The stage distribution in both groups consisted of 18% with stage Tis tumors, 71% with T1 tumors, and 11% with T2 tumors.
Significantly fewer patients in the partial breast irradiation group received adjuvant hormonal therapy (54%) compared with those in the whole breast irradiation group (68%). There was a trend toward smaller tumors in patients undergoing partial breast irradiation than in those receiving whole breast irradiation, with mean tumor sizes of 11.4 mm and 13 mm (P = .06).
Other characteristics were similar between the groups, including the proportion with negative lymph nodes (91% of patients undergoing partial breast irradiation and 86% of those who got whole breast irradiation), the proportion with negative final margins (94% and 95%, respectively), and the proportion who received adjuvant chemotherapy (15% and 18%).
Close tumor margins increased the risk for ipsilateral breast tumor recurrence in both groups, and positive margins increased the recurrence risk in the whole breast irradiation group, a univariate analysis found.
Dr. Wobb reported having no relevant financial disclosures.
On Twitter @sherryboschert
AT THE ASCO BREAST CANCER SYMPOSIUM
Major finding: Four percent developed local recurrence and 1% had regional recurrence in both partial and whole breast irradiation groups. For the partial vs. whole breast irradiation groups, distant metastases developed in 6% and 3%, disease-free survival rates were 91% and 93%, and overall survival rates were 75% and 82.
Data source: A retrospective study of 274 matched pairs of patients with early-stage breast cancer treated with breast-conserving therapy at one institution.
Disclosures: Dr. Wobb reported having no relevant financial disclosures.
