Brachytherapy in the Treatment of Breast Cancer

February 1, 2001

Dr. Subir Nag et al are to be congratulated for their excellent, thorough analysis and presentation of the use and role of

Dr. Subir Nag et al are to be congratulated for their excellent,thorough analysis and presentation of the use and role of brachytherapy in thetreatment of patients with breast cancer.

Brachytherapy: Long Time Coming

In 1896, Gocht[1] used x-rays in the treatment of breast cancer,1 year after Roentgen’s first report on his discovery. Radium was also used totreat early and advanced breast cancer very soon after its discovery. In 1924,Koenig[2] reported a 5-year survival of 21% for stage I breast cancer and 17%for stage II disease in patients treated with radium only.

In 1929, Keynes[3] suggested that it might be possible to curebreast cancer by means of irradiation. He described techniques in which radiumneedles were implanted into the breast tumor, axilla, and occasionally, theinternal mammary node region. He chose this modality on the basis of previousexperiences in which he had used preoperative irradiation and noted completedisappearance of the tumor when examined microscopically in about one-third ofcases.

McKittrick[4] agreed with Keynes that interstitial irradiationwas of use for tumors that occupied no more than
one-quarter of the breast. He consid-ered interstitial irradiation to be of novalue in operable patients because of sequelae (pain, fibrosis, and latedeformity).

The sequelae of brachytherapy led to its limited use until themid-1900s. At that time, the Europeans, especially the French—who hadcontinued to use radium in combination with orthovoltage therapy—began to useradium and other radioactive sources to give a boost dose to the tumor or tumorbed. On the basis of work by European investigators, such as Pierquin,[5,6] theuse of brachytherapy as a boost for breast cancer was given credence.

In the recent past, a few investigators opposed its use. Inaddition, the availability of the electron beam made boosting of the tumor sitemore practical. As a result of these issues, brachytherapy, even as a localboost, has been used only at a few centers in the United States.[7]

Necessity for Guidelineson Brachytherapy

Since most radiation oncologists do not have extensiveexperience in breast brachytherapy, it made good practical sense for theAmerican Brachytherapy Society (ABS) to develop guidelines for the clinical useof this strategy. The result has been a well-prepared and well-written document.

There are multiple methods for the use of brachytherapy in thetreatment of breast cancer. Among these techniques are:

As the Sole Method of Treatment: In the past, thismethod was used for patients with advanced disease. However, Dr. Kuske has begunto show favorable results in patients with early-stage disease.[8,9]

As a Low-Dose-Rate Boost Following External-BeamIrradiation: Although this method has been used in the United States, themajority of cases have been treated in France.[5,6]

As a Boost Before External-Beam Irradiation: This isperformed atthe time of surgical excision of the lump.[7,10,11] We have treated over 600patients using brachytherapy at the time of lumpectomy. We have noted excellentlocal control, survival, and cosmetic results.[12]

As a Mold to Treat Postmastectomy Recurrence on theChest Wall: The use of this method today would be very rare because of theavailability of the electron beam.

As a Low- or High-Dose Boost: This can be done with orwithout external-beam irradiation.[13,14]

In the conservative treatment of the breast, the local tumor isexcised with a 1- to 2-cm margin of normal tissue. As mentioned above, animplant can be performed at the time of lumpectomy.[10-12] However, the mostcommon approach has been to have the patient start on external-beam therapy tothe whole breast 1 to 2 weeks later. The adjacent nodes are treated, dependingon the location of the primary and status of the axillary nodes. The tumor bedis then boosted with electrons or an interstitial implant (photons are rarelyused, because they are associated with sequelae). The interstitial therapy canbe administered at a high or low dose rate.

The ABS panel discusses the indications, use, and evaluation ofbreast implants as the sole treatment modality following lumpectomy, as a boostfollowing whole-breast irradiation, and as a treatment of local recurrences. Aspointed out by the ABS, the use of brachytherapy as the sole method of treatmentto the tumor bed is being investigated in a randomized trial. At present, thisis not the recommended method of treatment, except in a randomized trialsetting. This is particularly true for patients with stage II disease, since ahigher percentage of their recurrences can occur outside of the tumor site.

Treat the Whole Breastor Tumor Site?

For more than 100 years, the treatment of early breast cancerhas been based on the concept that the whole breast needs to be treated. Thishas been supported by the fact that the whole breast is at risk for recurrentdisease. However, the majority of recurrences have occurred in the region of theoriginal tumor. As a result, a school of thought has arisen suggesting that itshould be possible to achieve a cure in the breast even if only the tumor sitein the breast is treated.[8, 9,13,14]

Conclusions

In summary, up until now, no real standards have been developedfor the use of brachytherapy in the breast. This paper establishes guidelinesthat are sorely needed in the brachytherapy community. Dr. Nag and the paneladdress important issues such as the clinical target volume, optimal volume,type of interstitial implants, use of templates, high dose rate, and dosimetry.Their work has resulted in a well-done reference article.

References:

1. Gocht W: Therapeutische Verwendungen der Röntgenstrahlen.Fortschr. Geb. Röntg-Strahl 1:14-22, 1897.

2. Koenig F: Geburtsh. Gynäk 87:270, 1924.

3. Keynes G: Treatment of primary carcinoma of the breast withradium. Acta Radiol 10:393-401, 1929.

4. McKittrick LS: Interstitial radiation of cancer of thebreast. Ann Surg 106:631, 1937.

5. Pierquin B: Can we treat small breast cancers (operablecancers) by radiotherapy alone? Ann Med Interne (Paris) 122:575-579, 1971.

6. Pierquin B, Raynal M, Chassagne D, et al: Radiothérapieseule dans le traitement des cancers du sein. Conservative treatment of breastcancer. Symp Int Strasbourg 1972, p 233. Paris, Masson, 1974.

7. Mansfield CM, Jewell WR: Intraoperative interstitialimplantation of iridium-192 in the breast. Radiology 150:600, 1984.

8. Kuske RR, Bolton JS, Wilenzick RM, et al: Brachytherapy asthe sole method of breast irradiation in TIS, T1, T2, N0-1 breast cancer. Int JRadiat Oncol Biol Phys 30(S1):245, 1994.

9. Kuske RR, Bolton JS, Harrison W: RTOG 95-17. A phase I/IItrial to evaluate brachytherapy as the sole method of radiation therapy forstage I and II breast carcinoma, pp 364. Radiation Therapy Oncology Group.Philadelphia, 1998.

10. Krishnan L, Jewell WR, Mansfield CM, et al: Perioperativeinterstitial irradiation of the conservative management of early breast cancer.Int J Radiat Oncol Biol Phys 13:1661-1665, 1987.

11. Mansfield CM: Intraoperative Ir-192 implantation for earlybreast cancer: Techniques and results. Cancer 66:1-5, 1990.

12. Mansfield CM, Komarnicky LT, Schwartz GF, et al: Ten yearresults in 1070 patients with stages I and II breast cancer treated byconservative surgery. Cancer 75(9):2328-2336, 1995.

13. Kestin LL, Jaffray DA, Edmundson GK, et al: Improving thedosimetric coverage of interstitial high-dose rate breast implants. Int J RadiatOncol Biol Phys 46(1):35-43, 2000.

14. Vicini F, Kini VR, Chen P, et al: Irradiation of the tumorbed alone after lumpectomy in selected patients with early-stage breast cancertreated with breast conserving therapy. J Surg Oncol 70(1):33-40, 1999.