Point/Counterpoint: Does Surgery Improve Survival in Stage IV Breast Cancer?

Yes – It Is Time to Consider a Paradigm Shift.

In stage IV breast cancer, local therapy is not considered important except for controlling symptoms. But recent large-scale retrospective studies tell us that, if you follow enough women long enough, you see a difference in survival related to control of local disease. These emerging data tell us it’s time to consider a paradigm shift in the treatment of stage IV breast cancer.

Researchers are finding that primary site treatment regimens are important because an intact primary tumor can serve as a continued source of new metastatic lesions. There is reason, therefore, to believe that treating these can prolong life.

First explored by Dr. Larry Norton and Joan Massagué, Ph.D., (Nature Med. 2006;12:875-8), the concept of cancer self-seeding holds that cells from the primary tumor not only travel unidirectionally to seed metastases but also return to the primary tumor, self-seeding it and helping it to grow even more.

This view incorporates the microenvironment of the primary tumor. Here, fibroblasts and other cells – particularly mesenchymal stem cells derived from bone marrow – may play a very important role, creating a reactive stroma that seems to release growth-promoting substances that increase the metastatic efficiency of the circulating cells.

Robert A. Weinberg, Ph.D., published data showing that these mesenchymal stem cells are pluripotent progenitor cells. When weakly metastatic human breast cancer cells were mixed with these stem cells, the cancer cells’ metastatic potential greatly increased. The breast cancer cells then stimulated the stem cells to secrete a chemokine which – in turn – enhanced the cancer cells’ motility and their ability to invade and metastasize (Nature 2007;449:557-63). In effect, the primary tumor acts like a filling station, giving these tumor cells more energy to go out and metastasize in different sites.

Although such studies remain animal models, I think we can say there is a basis for primary tumor therapy in the metastatic setting. A dozen or more retrospective studies of large institutional series, cancer databases, and population-based studies have examined outcomes in women treated with and without surgical resection. Data on about 30,000 women have been published, with about 50% receiving some form of primary tumor therapy. The survival benefit across them is quite consistent, with the hazard ratio of death over a given time period reduced from 30% to 50%.

These studies do demonstrate selection bias: Women treated with surgical removal were more likely to be young, white, married, with smaller tumors and a lower burden of disease, and it is possible that they would have done better anyway. Studies have also shown that better survival, even in stage IV cancer, occurs in women who have a therapeutic target (that is, hormone receptors or HER2). But there was still a significant survival benefit for surgery.

Surgical resection may also confer benefit by preventing the primary tumor in the breast from becoming a quality of-life problem. At Northwestern Memorial Hospital, Chicago, we conducted a study that showed the odds of symptomatic chest wall disease were far lower in the surgical group, compared with the nonsurgical group. In this 2008 study, we found that women with good local control– surgical or systemic - did better. Time to first progression was prolonged by 50% in the surgical group, while chest wall control was associated with a 60% improvement in overall survival, regardless of whether surgical resection was performed (Cancer 2008;113:2011-9).

So the question is, do we need a randomized trial? My unbiased answer is that we do – and I am the principal investigator of such a trial open to all U.S. and Canadian institutions (NCT01242800). The end points are survival, local control, and quality of life. In addition, the trial will provide an opportunity to answer biological questions regarding the relationship between the primary tumor and metastatic site. Only when we have samples of primary and metastatic tumors can we settle this continuing debate.

Dr. Khan is the Bluhm Family Professor of Cancer Research at the Lurie Comprehensive Cancer Center, Chicago.

No – Case Selection Bias Is Behind the Survival Advantage.

It’s true that some studies show an increase in stage IV breast cancer survival after primary site resection – but this more likely reflects a bias of case selection than a true benefit of local therapy.

Any findings of positive benefit other than case selection must be biologically plausible. The suggestion that the primary tumor releases some sort of growth-promoting substance that is gone when you remove the tumor, inhibiting metastatic disease has not yet been proven in humans; nor has the proposition that continued cell shedding might further metastasis.

Decreased tumor burden has sometimes been shown to increase the usefulness of systemic therapy, but I think that, all in all, case selection simply promotes breast surgery in patients with a better prognosis.

To show improved survival, we must find causality and not simply coincidence. Findings from large case series or cancer databases are unable to provide the answer. Although registry interpretations can provide basic data, they often break down when you attempt to extract detailed data.

Sometimes a stage IV cancer is registered initially on the basis of a pulmonary or liver shadow on imaging, which later is proven not to have been metastatic disease – and the case is never amended in the registry. There are also registry misinterpretations of the type of surgery that’s been done.

We performed a matched pair analysis of stage IV breast cancer patients with and without resection of the primary tumor. This was based on the Partners Health Care Consortium cancer database, which included information on 19,464 invasive breast cancers treated between 1970 and 2002; 808 of these (4%) were recorded as stage IV. Of these, 622 were analyzed by case matching that considered age, diagnostic date, metastatic disease location, estrogen-receptor status, and systemic therapy (Ann. Surg. Oncol. 2008; 15:3384-95).

It’s absolutely true that there was a statistically significant difference in survival in the overall comparison of surgery vs. no surgery. With bone metastases only, it was still statistically significant, but with a substantially lower difference in survival. In visceral metastases, the difference became nonsignificant.

Looking at therapy sequence in those who had the same type of systemic therapy, but with chemotherapy before or after surgery, you see a suggestion that giving systemic therapy first with a clinical response, which is a favorable prognostic indication, leads to a selection bias in choosing patients for surgery.

I reviewed the 86 cases who survived 5 years with records available. In those records, 22 were actually not stage IV disease, leaving 64 with confirmed stage IV (M1) – an overall 10% 5-year survival rate. Patients who survived were significantly younger than those who did not survive, significantly more likely to have estrogen receptor-positive tumors, and significantly more likely to have bone rather than visceral metastases or oligometastatic disease – all of which are good prognostic factors.

Among the 64 5-year survivors, 25 had therapeutic breast surgery. Of these, 8 had an excellent chemotherapy response followed by breast surgery; 8 had delayed surgery following a failure of systemic therapy; 7 had an initial therapeutic and curative surgery, but staging revealed metastases because of unexpected positive nodes; and 2 had initial surgery with oligometastatic resection.

Thirty-nine patients had no therapeutic breast surgery, and, of these, 16 had an excellent response to systemic therapy; 15 had slowly progressive disease; and 8 had oligometastatic disease – a positive prognostic factor. Thus, favorable prognostic factors led to a selection of primary-site surgery, whereas poor prognostic factors mean that primary-site surgery was avoided, contradicting the assumption of its therapeutic benefit.

There were also surgical discrepancies among the 5-year survivors. The registry listed 11 as having had breast surgery, while a chart review showed that surgery was not therapeutic. Five were listed as having no breast surgery, while they had indeed undergone a therapeutic operation.

Cancer registry data are not reliable for defining stage IV disease, discriminating advanced local disease with bone involvement from true distant, imaging-confirmed metastasis, or assessing surgical procedures. Case selection bias accounts for most, if not all, of the apparent survival advantage.

Dr. Blake Cady is professor of surgery (emeritus) at Harvard Medical School, Boston, and at Brown University, Providence, R.I.

Yes – It Is Time to Consider a Paradigm Shift.

In stage IV breast cancer, local therapy is not considered important except for controlling symptoms. But recent large-scale retrospective studies tell us that, if you follow enough women long enough, you see a difference in survival related to control of local disease. These emerging data tell us it’s time to consider a paradigm shift in the treatment of stage IV breast cancer.

Researchers are finding that primary site treatment regimens are important because an intact primary tumor can serve as a continued source of new metastatic lesions. There is reason, therefore, to believe that treating these can prolong life.

First explored by Dr. Larry Norton and Joan Massagué, Ph.D., (Nature Med. 2006;12:875-8), the concept of cancer self-seeding holds that cells from the primary tumor not only travel unidirectionally to seed metastases but also return to the primary tumor, self-seeding it and helping it to grow even more.

This view incorporates the microenvironment of the primary tumor. Here, fibroblasts and other cells – particularly mesenchymal stem cells derived from bone marrow – may play a very important role, creating a reactive stroma that seems to release growth-promoting substances that increase the metastatic efficiency of the circulating cells.

Robert A. Weinberg, Ph.D., published data showing that these mesenchymal stem cells are pluripotent progenitor cells. When weakly metastatic human breast cancer cells were mixed with these stem cells, the cancer cells’ metastatic potential greatly increased. The breast cancer cells then stimulated the stem cells to secrete a chemokine which – in turn – enhanced the cancer cells’ motility and their ability to invade and metastasize (Nature 2007;449:557-63). In effect, the primary tumor acts like a filling station, giving these tumor cells more energy to go out and metastasize in different sites.

Although such studies remain animal models, I think we can say there is a basis for primary tumor therapy in the metastatic setting. A dozen or more retrospective studies of large institutional series, cancer databases, and population-based studies have examined outcomes in women treated with and without surgical resection. Data on about 30,000 women have been published, with about 50% receiving some form of primary tumor therapy. The survival benefit across them is quite consistent, with the hazard ratio of death over a given time period reduced from 30% to 50%.

These studies do demonstrate selection bias: Women treated with surgical removal were more likely to be young, white, married, with smaller tumors and a lower burden of disease, and it is possible that they would have done better anyway. Studies have also shown that better survival, even in stage IV cancer, occurs in women who have a therapeutic target (that is, hormone receptors or HER2). But there was still a significant survival benefit for surgery.

Surgical resection may also confer benefit by preventing the primary tumor in the breast from becoming a quality of-life problem. At Northwestern Memorial Hospital, Chicago, we conducted a study that showed the odds of symptomatic chest wall disease were far lower in the surgical group, compared with the nonsurgical group. In this 2008 study, we found that women with good local control– surgical or systemic - did better. Time to first progression was prolonged by 50% in the surgical group, while chest wall control was associated with a 60% improvement in overall survival, regardless of whether surgical resection was performed (Cancer 2008;113:2011-9).

So the question is, do we need a randomized trial? My unbiased answer is that we do – and I am the principal investigator of such a trial open to all U.S. and Canadian institutions (NCT01242800). The end points are survival, local control, and quality of life. In addition, the trial will provide an opportunity to answer biological questions regarding the relationship between the primary tumor and metastatic site. Only when we have samples of primary and metastatic tumors can we settle this continuing debate.

Dr. Khan is the Bluhm Family Professor of Cancer Research at the Lurie Comprehensive Cancer Center, Chicago.

No – Case Selection Bias Is Behind the Survival Advantage.

It’s true that some studies show an increase in stage IV breast cancer survival after primary site resection – but this more likely reflects a bias of case selection than a true benefit of local therapy.

Any findings of positive benefit other than case selection must be biologically plausible. The suggestion that the primary tumor releases some sort of growth-promoting substance that is gone when you remove the tumor, inhibiting metastatic disease has not yet been proven in humans; nor has the proposition that continued cell shedding might further metastasis.

Decreased tumor burden has sometimes been shown to increase the usefulness of systemic therapy, but I think that, all in all, case selection simply promotes breast surgery in patients with a better prognosis.

To show improved survival, we must find causality and not simply coincidence. Findings from large case series or cancer databases are unable to provide the answer. Although registry interpretations can provide basic data, they often break down when you attempt to extract detailed data.

Sometimes a stage IV cancer is registered initially on the basis of a pulmonary or liver shadow on imaging, which later is proven not to have been metastatic disease – and the case is never amended in the registry. There are also registry misinterpretations of the type of surgery that’s been done.

We performed a matched pair analysis of stage IV breast cancer patients with and without resection of the primary tumor. This was based on the Partners Health Care Consortium cancer database, which included information on 19,464 invasive breast cancers treated between 1970 and 2002; 808 of these (4%) were recorded as stage IV. Of these, 622 were analyzed by case matching that considered age, diagnostic date, metastatic disease location, estrogen-receptor status, and systemic therapy (Ann. Surg. Oncol. 2008; 15:3384-95).

It’s absolutely true that there was a statistically significant difference in survival in the overall comparison of surgery vs. no surgery. With bone metastases only, it was still statistically significant, but with a substantially lower difference in survival. In visceral metastases, the difference became nonsignificant.

Looking at therapy sequence in those who had the same type of systemic therapy, but with chemotherapy before or after surgery, you see a suggestion that giving systemic therapy first with a clinical response, which is a favorable prognostic indication, leads to a selection bias in choosing patients for surgery.

I reviewed the 86 cases who survived 5 years with records available. In those records, 22 were actually not stage IV disease, leaving 64 with confirmed stage IV (M1) – an overall 10% 5-year survival rate. Patients who survived were significantly younger than those who did not survive, significantly more likely to have estrogen receptor-positive tumors, and significantly more likely to have bone rather than visceral metastases or oligometastatic disease – all of which are good prognostic factors.

Among the 64 5-year survivors, 25 had therapeutic breast surgery. Of these, 8 had an excellent chemotherapy response followed by breast surgery; 8 had delayed surgery following a failure of systemic therapy; 7 had an initial therapeutic and curative surgery, but staging revealed metastases because of unexpected positive nodes; and 2 had initial surgery with oligometastatic resection.

Thirty-nine patients had no therapeutic breast surgery, and, of these, 16 had an excellent response to systemic therapy; 15 had slowly progressive disease; and 8 had oligometastatic disease – a positive prognostic factor. Thus, favorable prognostic factors led to a selection of primary-site surgery, whereas poor prognostic factors mean that primary-site surgery was avoided, contradicting the assumption of its therapeutic benefit.

There were also surgical discrepancies among the 5-year survivors. The registry listed 11 as having had breast surgery, while a chart review showed that surgery was not therapeutic. Five were listed as having no breast surgery, while they had indeed undergone a therapeutic operation.

Cancer registry data are not reliable for defining stage IV disease, discriminating advanced local disease with bone involvement from true distant, imaging-confirmed metastasis, or assessing surgical procedures. Case selection bias accounts for most, if not all, of the apparent survival advantage.

Dr. Blake Cady is professor of surgery (emeritus) at Harvard Medical School, Boston, and at Brown University, Providence, R.I.

Yes – It Is Time to Consider a Paradigm Shift.

In stage IV breast cancer, local therapy is not considered important except for controlling symptoms. But recent large-scale retrospective studies tell us that, if you follow enough women long enough, you see a difference in survival related to control of local disease. These emerging data tell us it’s time to consider a paradigm shift in the treatment of stage IV breast cancer.

Researchers are finding that primary site treatment regimens are important because an intact primary tumor can serve as a continued source of new metastatic lesions. There is reason, therefore, to believe that treating these can prolong life.

First explored by Dr. Larry Norton and Joan Massagué, Ph.D., (Nature Med. 2006;12:875-8), the concept of cancer self-seeding holds that cells from the primary tumor not only travel unidirectionally to seed metastases but also return to the primary tumor, self-seeding it and helping it to grow even more.

This view incorporates the microenvironment of the primary tumor. Here, fibroblasts and other cells – particularly mesenchymal stem cells derived from bone marrow – may play a very important role, creating a reactive stroma that seems to release growth-promoting substances that increase the metastatic efficiency of the circulating cells.

Robert A. Weinberg, Ph.D., published data showing that these mesenchymal stem cells are pluripotent progenitor cells. When weakly metastatic human breast cancer cells were mixed with these stem cells, the cancer cells’ metastatic potential greatly increased. The breast cancer cells then stimulated the stem cells to secrete a chemokine which – in turn – enhanced the cancer cells’ motility and their ability to invade and metastasize (Nature 2007;449:557-63). In effect, the primary tumor acts like a filling station, giving these tumor cells more energy to go out and metastasize in different sites.

Although such studies remain animal models, I think we can say there is a basis for primary tumor therapy in the metastatic setting. A dozen or more retrospective studies of large institutional series, cancer databases, and population-based studies have examined outcomes in women treated with and without surgical resection. Data on about 30,000 women have been published, with about 50% receiving some form of primary tumor therapy. The survival benefit across them is quite consistent, with the hazard ratio of death over a given time period reduced from 30% to 50%.

These studies do demonstrate selection bias: Women treated with surgical removal were more likely to be young, white, married, with smaller tumors and a lower burden of disease, and it is possible that they would have done better anyway. Studies have also shown that better survival, even in stage IV cancer, occurs in women who have a therapeutic target (that is, hormone receptors or HER2). But there was still a significant survival benefit for surgery.

Surgical resection may also confer benefit by preventing the primary tumor in the breast from becoming a quality of-life problem. At Northwestern Memorial Hospital, Chicago, we conducted a study that showed the odds of symptomatic chest wall disease were far lower in the surgical group, compared with the nonsurgical group. In this 2008 study, we found that women with good local control– surgical or systemic - did better. Time to first progression was prolonged by 50% in the surgical group, while chest wall control was associated with a 60% improvement in overall survival, regardless of whether surgical resection was performed (Cancer 2008;113:2011-9).

So the question is, do we need a randomized trial? My unbiased answer is that we do – and I am the principal investigator of such a trial open to all U.S. and Canadian institutions (NCT01242800). The end points are survival, local control, and quality of life. In addition, the trial will provide an opportunity to answer biological questions regarding the relationship between the primary tumor and metastatic site. Only when we have samples of primary and metastatic tumors can we settle this continuing debate.

Dr. Khan is the Bluhm Family Professor of Cancer Research at the Lurie Comprehensive Cancer Center, Chicago.

No – Case Selection Bias Is Behind the Survival Advantage.

It’s true that some studies show an increase in stage IV breast cancer survival after primary site resection – but this more likely reflects a bias of case selection than a true benefit of local therapy.

Any findings of positive benefit other than case selection must be biologically plausible. The suggestion that the primary tumor releases some sort of growth-promoting substance that is gone when you remove the tumor, inhibiting metastatic disease has not yet been proven in humans; nor has the proposition that continued cell shedding might further metastasis.

Decreased tumor burden has sometimes been shown to increase the usefulness of systemic therapy, but I think that, all in all, case selection simply promotes breast surgery in patients with a better prognosis.

To show improved survival, we must find causality and not simply coincidence. Findings from large case series or cancer databases are unable to provide the answer. Although registry interpretations can provide basic data, they often break down when you attempt to extract detailed data.

Sometimes a stage IV cancer is registered initially on the basis of a pulmonary or liver shadow on imaging, which later is proven not to have been metastatic disease – and the case is never amended in the registry. There are also registry misinterpretations of the type of surgery that’s been done.

We performed a matched pair analysis of stage IV breast cancer patients with and without resection of the primary tumor. This was based on the Partners Health Care Consortium cancer database, which included information on 19,464 invasive breast cancers treated between 1970 and 2002; 808 of these (4%) were recorded as stage IV. Of these, 622 were analyzed by case matching that considered age, diagnostic date, metastatic disease location, estrogen-receptor status, and systemic therapy (Ann. Surg. Oncol. 2008; 15:3384-95).

It’s absolutely true that there was a statistically significant difference in survival in the overall comparison of surgery vs. no surgery. With bone metastases only, it was still statistically significant, but with a substantially lower difference in survival. In visceral metastases, the difference became nonsignificant.

Looking at therapy sequence in those who had the same type of systemic therapy, but with chemotherapy before or after surgery, you see a suggestion that giving systemic therapy first with a clinical response, which is a favorable prognostic indication, leads to a selection bias in choosing patients for surgery.

I reviewed the 86 cases who survived 5 years with records available. In those records, 22 were actually not stage IV disease, leaving 64 with confirmed stage IV (M1) – an overall 10% 5-year survival rate. Patients who survived were significantly younger than those who did not survive, significantly more likely to have estrogen receptor-positive tumors, and significantly more likely to have bone rather than visceral metastases or oligometastatic disease – all of which are good prognostic factors.

Among the 64 5-year survivors, 25 had therapeutic breast surgery. Of these, 8 had an excellent chemotherapy response followed by breast surgery; 8 had delayed surgery following a failure of systemic therapy; 7 had an initial therapeutic and curative surgery, but staging revealed metastases because of unexpected positive nodes; and 2 had initial surgery with oligometastatic resection.

Thirty-nine patients had no therapeutic breast surgery, and, of these, 16 had an excellent response to systemic therapy; 15 had slowly progressive disease; and 8 had oligometastatic disease – a positive prognostic factor. Thus, favorable prognostic factors led to a selection of primary-site surgery, whereas poor prognostic factors mean that primary-site surgery was avoided, contradicting the assumption of its therapeutic benefit.

There were also surgical discrepancies among the 5-year survivors. The registry listed 11 as having had breast surgery, while a chart review showed that surgery was not therapeutic. Five were listed as having no breast surgery, while they had indeed undergone a therapeutic operation.

Cancer registry data are not reliable for defining stage IV disease, discriminating advanced local disease with bone involvement from true distant, imaging-confirmed metastasis, or assessing surgical procedures. Case selection bias accounts for most, if not all, of the apparent survival advantage.

Dr. Blake Cady is professor of surgery (emeritus) at Harvard Medical School, Boston, and at Brown University, Providence, R.I.