A healthy 59-year-old woman presents with a biopsy-positive palpable breast mass. Mammographic evaluation reveals a unicentric 2.2-cm infiltrating ductal carcinoma involving the outer aspect of the left breast. Lumpectomy and sentinel lymph node evaluation are completed revealing a 2.0-cm grade III infiltrating ductal carcinoma resected with negative margins. The lesion is ER- PR- and the sentinel lymph node is negative.
top of page
Expert Commentary:
Manjeet Chadha, MD
Associate Chairman, Radiation Oncology, Beth Israel Medical Center, New York, NY
Background: Local treatment option for this patient includes breast conserving surgery followed by radiation therapy, and modified radical mastectomy with or without reconstruction. For the most part, a pathologic stage T2N0 is preferably managed with breast conserving therapy as this allows organ preservation and has similar long term outcome as that afforded by modified radical mastectomy. The radiation therapy standard of care is typically a course of whole breast irradiation followed by a boost to the lumpectomy site.1
With a better understanding of the patterns of failure reported with longterm follow up2 more recently it has been hypothesized that partial breast irradiation to the lumpectomy site may be all that is needed to realize the benefits of improved local control from radiation therapy. Accordingly, patients can be spared the side effects of whole breast irradiation. Furthermore, with the reduced target breast volume there is an opportunity to safely accelerate the radiation treatment that can be completed in oneweek as compared to the six-week course of daily therapy.
Partial breast irradiation may be administered using the traditional multiple catheter technique or the Mammosite single catheter technique. Both high dose rate and low dose rate brachytherapy has been applied with these techniques. To overcome the risk of infection patients are prescribed prophylactic antibiotics during brachytherapy. External beam therapy using intensity modulated radiation therapy (IMRT), 3-dimensional conformal treatment are also being studied for the safety and efficacy of administering partial breast irradiation. Intraoperative techniques using soft x-rays, electron beam and HDR Ir-192 brachytherapy are also under investigation. There are presently no data to suggest that one technique is superior to the other.
In selection of technique for patients there has to be consideration on the available expertise at the given institution. In addition, there are patient characteristics such as breast shape and size, tumor characteristics like size and location of tumor and certain anatomical considerations that the radiation oncologist and breast surgeon must take into consideration when making a decision on choice of technique.
Single institutional experience, registry trial, as well as phase II single arm study3-5 has studied partial breast irradiation using brachytherapy. The majority of the women undergoing partial breast irradiation were over the age of 60 with IDC less than 2 cm, no extensive intraductal component, negative surgical margins. Although, women with 1-3 positive nodes were included, the majority of the patients had negative sentinel nodes. Early results suggest that the brachytherapy treatment is safe and results in good local control. It is important to recognize the responsibility of the medical team to acquire training to become proficient with the PBI technique that is selected at their institution so as not to harm the patient in the long run.
Current phase III NSABP B-39/RTOG 0413 study is ongoing with an accrual goal of 3,000 patients over 2.5 years. Figure 1 illustrates the schema and figure 2 the treatment regimen of this protocol. The eligibility criteria for this study include stage 0, I, II with tumor < 3 cm and all surgical margins of resection should be negative. Patients with up to 3 positive lymph nodes are eligible to enroll in this study.
Recommendation: In this particular case I would encourage the patient to participate in the NSABP-B39/RTOG 0413 clinical trial. This is often difficult to do as most patients actively participate in their treatment decisions and have a preconceived notion of what they want, i.e., standard whole breast or partial breast.
If the patient did not consent for the study I would counsel the patient that off protocol, she should receive whole breast irradiation. At present, the majority of clinical data studies using partial breast irradiation have included favorable histologic grade and older women, i.e., low to intermediate grade tumors. Therefore the factor of poor grade becomes a point of significant concern, and to a lesser extent her age is also a consideration.
References
1. Fisher, B.; Anderson S.; Redmond CK et al; reanalysis and results after 12 years of follow up in a randomized clinical trial comparing mastectomy with lumpectomy with and without radiation in the treatment of breast cancer. N Engl J Med 333: 1456,1995
2. Veronesi U, Marubini E, Milani A, et al. Breast conserving surgery with or without postoperative radiotherapy. Long term results of a randomized trial. Ann Oncol 2001, 12, 997-1003.
3. King TA, Bolton JS, Kuske BR, et al: Long-term results of wide-field brachytherapy as the sole modality of radiation therapy after segmental mastectomy for Tis,1, 2 breast cancer. Ann J Surg 2000; 180: 299-304
4. Vicini FA, Baglani KI, Kestin LI, Et al: Accelerated treatment of breast cancer J. Clin Oncol; 19;7,1993-2001.
5. Kuske RTOG Phase II protocol
top of page
Accelerated Partial Breast Radiation:
Good for All Early Stage Breast Cancer?
Merav Ben-David, MD, Research Fellow, and Lori J. Pierce, MD, Professor, Department of Radiation Oncology, Associate Provost, University of Michigan Comprehensive Cancer Center, Ann Arbor
Breast conserving therapy with whole breast radiation has been shown to be equivalent, in terms of survival, with mastectomy and is now considered the treatment of choice for early stage breast cancer. Conventional whole breast radiation therapy results in 90% of local control. Therefore, for one to consider deviating from the standard of care to less than whole breast radiotherapy, partial breast radiotherapy would have to offer less toxicity and/or more convenience while maintaining excellent rates of local control.
While patient, physician and media pressure to use partial breast radiation is growing, it is essential to realize that this approach is still investigational, as there is no long term follow-up for local control and toxicity for the single institution studies reported, and there is no contemporary randomized trial that compared whole breast vs. partial breast irradiation. Therefore, patients should only be treated within the context of a clinical trial.
A major consideration when contemplating APBI is appropriate patient selection factors. Negative surgical margin and the restriction to smaller tumors are the only two criteria that have been consistently applied within the successful APBI trials. These criteria are true for treating early stage breast cancer with whole breast radiation and therefore patients who are not candidates for whole breast radiation should not be considered for APBI. This was demonstrated in a series from the Guy’s Hospital, London that treated patients with partial breast radiation using low dose rate Brachytherapy1. After 6 years of follow-up, they found local recurrence in 37% of 27 patients. However, 56% of the patients had positive surgical margins and although only tumors measuring 4cm or less were eligible, 3 patients had larger tumors.
Also, women who are at risk for familial/genetic breast cancer should be informed that our knowledge about APBI in their unique situation is scarce.
For this 59 year-old patient who is interested in a short course of radiotherapy, participating in an accelerated partial breast radiation study is a possible treatment option. She has a T1 cancer, the margins are negative and there are no positive lymph nodes. However, important issues need to be cleared before she can proceed with any type of adjuvant radiation. There is no information about the presence/absence of microcalcifications in her diagnostic mammogram. If the tumor was associated with suspicious microcalcifications, a post lumpectomy mammogram should be performed to assure excision of all suspected areas; if residual suspicious microcalcifications are found, a re-excision is needed. More pathologic details need to be documented: was there any extensive intraductal component or areas of lymphatic- small vessels invasion that can influence her inherent risk for local recurrence? Those factors will be evaluated and incorporated into the analysis of the RTOG/NSABP trial.
Finally, the discussion about partial breast irradiation should include the short follow-up time available for patients who have already been treated with this technique, as opposed to more then 15-20 years with conventional whole breast radiation. Also, a consult with medical oncologist should be scheduled to discuss the possibility of adjuvant chemotherapy in her case, since she is hormone receptor negative.
When all of these points are adequately addressed, we would recommend that the patient consider participation in the national APBI versus whole breast RT study, as it will ultimately answer the question whether, in a controlled randomized trial of adequate power, APBI is equivalent to traditional whole breast radiation therapy with respect to local control, quality of life, toxicity and survival. It will not, however, answer whether one form of APBI is more effective than another or better suited for specific patients or specific cancer types. The answer to these and other questions will await further study.
Reference
1. Fentiman IS, Poole C, Tong D, et al. Inadequacy of iridium implant as sole radiation treatment for operable breast cancer. Eur J Cancer. 1996; 32A(4):608-611.
top of page
|
