The time-course of metastases from breast cancer after mastectomy and breast-conserving surgery with and without isolated local-regional recurrence.

We have examined time intervals between events in 390 metastatic breast cancer (MBC) patients whose distant failure developed within 10 years from initial surgery of Stage I/II disease. All of the patients underwent axillary dissection and mastectomy (n=295) or breast-conserving surgery (BCS, n=95), between 1983 and 1987. Distinctions have been made between distant failure with (n=79) and without (n=311) isolated local-regional recurrence (LRR). The median survival time after first relapse was significantly longer with intrabreast (30 months) and chest wall (24 months) than with distant relapse (15 months), but with axillary (17 months) or with supraclavicular (17 months) relapse survival was similar. The delay between LRR and distant metastasis was shorter with axillary (7 months) and supraclavicular (9 months) than with breast (20 months) and chest wall (12 months) recurrences. The median postmetastatic survival time by site of first relapse was significantly shorter with supraclavicular (6 months) and axillary (9 months) than with distant site relapse (15 months) but with intrabreast (12 months) or with chest wall (11 months) recurrence survival was similar. In MBC, regional recurrences are associated with a shorter interval between events than with local recurrences. The shortened intervals for patients with regional recurrence suggest that metastases existed at the time of initial surgery. The question of whether prevention of local or regional recurrence or both improves cause-specific survival after mastectomy or BCS needs to be answered in randomized studies.

CT-image-based conformal brachytherapy of breast cancer. The significance of semi-3-D and 3-D treatment planning.

PURPOSE: To compare the conventional 2-D, the simulator-guided semi-3-D and the recently developed CT-guided 3-D brachytherapy treatment planning in the interstitial radiotherapy of breast cancer. PATIENTS AND METHODS: In 103 patients with T1-2, N0-1 breast cancer the tumor bed was clipped during breast conserving surgery. Fifty-two of them received boost brachytherapy after 46 to 50 Gy teletherapy and 51 patients were treated with brachytherapy alone via flexible implant tubes. Single, double and triple plane implant was used in 6, 89 and 8 cases, respectively. The dose of boost brachytherapy and sole brachytherapy prescribed to dose reference points was 3 times 4.75 Gy and 7 times 5.2 Gy, respectively. The positions of dose reference points varied according to the level (2-D, semi-3-D and 3-D) of treatment planning performed. The treatment planning was based on the 3-D reconstruction of the surgical clips, implant tubes and skin points. In all cases the implantations were planned with a semi-3-D technique aided by simulator. In 10 cases a recently developed CT-guided 3-D planning system was used. The semi-3-D and 3-D treatment plans were compared to hypothetical 2-D plans using dose-volume histograms and dose non-uniformity ratios. The values of mean central dose, mean skin dose, minimal clip dose, proportion of underdosaged clips and mean target surface dose were evaluated. The accuracy of tumor bed localization and the conformity of planning target volume and treated volume were also analyzed in each technique. RESULTS: With the help of conformal semi-3-D and 3-D brachytherapy planning we could define reference dose points, active source positions and dwell times individually. This technique decreased the mean skin dose with 22.2% and reduced the possibility of geographical miss. We could achieve the best conformity between the planning target volume and the treated volume with the CT-image based 3-D treatment planning, at the cost of worse dose homogeneity. The mean treated volume was reduced by 25.1% with semi-3-D planning, however, it was increased by 16.2% with 3-D planning, compared to the 2-D planning. CONCLUSION: The application of clips into the tumor bed and the conformal (semi-3-D and 3-D) planning help to avoid geographical miss. CT is suitable for 3-D brachytherapy planning. Better local control with less side effects might be achieved with these new techniques. Conformal 3-D brachytherapy calls for new treatment planning concepts, taking the irregular 3-D shape of the target volume into account. The routine clinical application of image-based 3-D brachytherapy is a real aim in the very close future.

Sole brachytherapy of the tumor bed after breast conserving surgery: a new radiotherapeutic strategy for patients at low risk of local relapse.

The aim of the study was to test the hypothesis, if there were subgroups of early breast cancer patients in which sole brachytherapy (BT) of the tumor bed was a feasible and safe treatment option after breast conserving surgery (BCS). Forty four prospectively selected patients with Stage I-II breast cancer were entered into a protocol of postoperative tumor bed irradiation using interstitial high dose rate (HDR) implants. The HDR fractionation schedules were calculated according to the linear quadratic model. In 8 patients 7 x 4.33 Gy, in the other 36 patients 7 x 5.2 Gy were delivered to the tumor bed with 2 cm margin. The treatment planning was based on the 3 dimensional (3D) reconstruction of the clipped excision cavity, catheters and skin points. A conformal semi-3D dose planning was used. The side effects were assessed by mammograms, MRI- and clinical examinations. At a median follow up of 20 (7-36) months 1 (2.3%) local and 1 (2.3%) regional failure was observed. Distant metastasis did not occur. The cosmetic results were judged to be excellent in each case. G2 radiation side effects were observed in 2 (4.5%) cases. Postoperative sole BT of the tumor bed with careful patient selection and adequate quality assurance seems to be a feasible alternative to whole breast radiotherapy after BCS. Sole BT shortens the time of radiotherapy from 5-6 weeks to 5 days, and reduces the costs of treatment. The skin and volume sparing effect of interstitial irradiation may decrease the side effects of radiotherapy. A randomized study is in progress to define which subgroups of patients should be candidates for BT alone after BCS.