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No benefit to intentionally targeting the internal mammary lymph nodes in conservatively managed breast cancer patients
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I. J. Radiation O n c o l o g y • B i o l o g y • Physics
V o l u m e 42, N u m b e r 1 Supplement, 1998
2037 NO BENEFIT TO INTENTIONALLY TARGETING THE INTERNAL MAMMARY LYMPH NODES LN CONSERVATIVELY MANAGED BREAST CANCER PATIENTS.
Edward Obedian, MD and Bruce Haffty, MD Yale University School of Medicine, Department of Therapeutic Radiology Purpose/Objective: Recent randomized trials have demonstrated a significant benefit to postmastectomy radiation in stage II and III breast cancer patients. The contribution of internal mammary chain radiation (IMCR) to this benefit remains controversial, and in conservatively treated patients (CS+RT) may compromise cosmesis and contribute to morbidity. The purpose of this retrospective analysis is to evaluate outcome as a function of IMCR in a large cohort of patients treated with CS+RT. Materials and Methods: Between 1/70 and 12/90, 957 breast cancer patients were treated at our facility with CS+RT and serve as the population base for tbJs study. Among these, 570 patients were pathologically staged with axillary node dissections which yielded 402 node negative patients and 168 node positive patients. All patients were treated with tangential fields +/- supraclavicular/axillaryfields +/- internal mammary fields. For this analysis, patients were divided into two groups: those treated with a separate internal mammary field (IM-yes, N=489) and without a separate internal mammary field (IM-no, N=408). When the internal mammary lymph nodes were not intentionally targeted, the medial border of the tangential fields was typically placed at midline. The decision not to target internal mammary nodes was a result of a change in treatment policy over time and generally not based on number of nodes or tumor location. Results: As of 2/98 with median follow-up of 12.3 years, the overall survival (OS), breast relapse free survival (BRFS), and distant relapse free survival (DRFS) rates at 10 years in the entire cohort of patients are 72%, 85%, and 77°4, respectively. The were no significant differences between the 1M-yes and IM-no groups with respect to age, T stage, ER status, location in breast, or use of adjuvant chemotherapy or hormone therapy. More patients in the IM-yes group had node positive disease, and of those there was a trend toward more patients with four or more positive nodes and slightly longer follow-up in the lM-yes group. Patients with node positive or PR positive tumors were more likely to be in the IM-yes group (p=0.0004 and 0.00175, respectively). Although there was a trend toward a better outcome in the IM-no group, there were no significant differences between the IM-yes and IM-no groups with respect to OS (73% IM-yes vs. 74% 1M-no, p>0.5), BRFS (84% IM-yes vs. 87% IM-no, p=0.305), or DMFS (75% IM-yes vs. 80% IM-no, p=0.095). Subset analysis showed no benefit in the IM-yes group regardless of age, number of nodes, or location. Conclusion: In this retrospective analysis, no benefit could be attributed to IMCR in conservatively treated patients even in patients with medial tumors and/or node positive disease. Until the results of an ongoing EORTC randomized trial addressing this issue are available, we will not intentionally target the internal mammary lymph nodes in conservatively managed breast cancer patients.
2038 CT ASSESSMENT OF SUPRACLAVICULAR AND INTERNAL MAMMARY LYMPH NODE DEPTH FOR ADJUVANT RADIA~ON OF BREASTCANCER Anne R. McCall, M.D., Mary Olson, M.D.* and Matthew Krasin, M.D. Depar~nents of Radiotherapy and *Radiology, Loyola University Medical Center Purpose: Several recent randomized trials have demonstrated a survival advantage with adjuvant regional nodal irradiation in women with breast cancer after mastectomy, yet the benefits in high risk women treated with breast preservation remain controversial. This study determined the depth of supraclavicular and internal mammary lymph nodes in 50 women and used CT-based treatment planning to determine the dose to these nodal areas using current treatment recommendations. Methods: The computerized tomograms (CT's) of 50 consecutive adult women were evaluated. The depth of the supraclavicular nodes were measured at the anterior border of the C7 vertebral body. The depth of the internal mammary lymph nodes were determined at the refleefion of the parastemal pleura in the 3rd intercostal space. The dose to the nodes at various depths were compared to isodose curves using standard published techniques, Results: The supraclavicular lymph nodes ranged in depth from 3.1 to 10.5 cm, with a median of 5.0 cm and an average depth 0f5.2 cm. If"standard" treatment was prescribed, giving 50 Gy to a depth of 3 cm using 6 mv photons, 52% of the patients would receive less than 90% of the prescribed dose and 22% would receive less than 85% of the desired dose to the supraclavicular nodes.. The depth of the internal mammary nodes ranged from 1.2 cm to 7.0 cm, with a median of 2.5 cm and an average depth of 2.9 cm. If "standard" treatment was prescribed giving 50 Gy to a depth of 4 cm using mixed photons and electrons, 68% of the patients would have the dose prescribed at least 1 cm deeper than appropriate, potentially risking underlying heart and lung to excessive treatment. Conclusion: "Standard" dose prescriptions for regional lymphatic radiation in women with breast cancer can result in many patients receiving inadequate dose to the supraclavicular lymphatics and may cause significant unnecessary dose beneath the internal mammary lymph nodes. All women who are given adjuvant radiation to regional lymphatics should undergo CT-based treatment planning to assure adequate coverage of target volumes. Results of clinical trials need to be evaluated in light of the adequacy of each trial's radiation techniques.
I. J. Radiation O n c o l o g y • B i o l o g y • Physics
V o l u m e 42, N u m b e r 1 Supplement, 1998
2037 NO BENEFIT TO INTENTIONALLY TARGETING THE INTERNAL MAMMARY LYMPH NODES LN CONSERVATIVELY MANAGED BREAST CANCER PATIENTS.
Edward Obedian, MD and Bruce Haffty, MD Yale University School of Medicine, Department of Therapeutic Radiology Purpose/Objective: Recent randomized trials have demonstrated a significant benefit to postmastectomy radiation in stage II and III breast cancer patients. The contribution of internal mammary chain radiation (IMCR) to this benefit remains controversial, and in conservatively treated patients (CS+RT) may compromise cosmesis and contribute to morbidity. The purpose of this retrospective analysis is to evaluate outcome as a function of IMCR in a large cohort of patients treated with CS+RT. Materials and Methods: Between 1/70 and 12/90, 957 breast cancer patients were treated at our facility with CS+RT and serve as the population base for tbJs study. Among these, 570 patients were pathologically staged with axillary node dissections which yielded 402 node negative patients and 168 node positive patients. All patients were treated with tangential fields +/- supraclavicular/axillaryfields +/- internal mammary fields. For this analysis, patients were divided into two groups: those treated with a separate internal mammary field (IM-yes, N=489) and without a separate internal mammary field (IM-no, N=408). When the internal mammary lymph nodes were not intentionally targeted, the medial border of the tangential fields was typically placed at midline. The decision not to target internal mammary nodes was a result of a change in treatment policy over time and generally not based on number of nodes or tumor location. Results: As of 2/98 with median follow-up of 12.3 years, the overall survival (OS), breast relapse free survival (BRFS), and distant relapse free survival (DRFS) rates at 10 years in the entire cohort of patients are 72%, 85%, and 77°4, respectively. The were no significant differences between the 1M-yes and IM-no groups with respect to age, T stage, ER status, location in breast, or use of adjuvant chemotherapy or hormone therapy. More patients in the IM-yes group had node positive disease, and of those there was a trend toward more patients with four or more positive nodes and slightly longer follow-up in the lM-yes group. Patients with node positive or PR positive tumors were more likely to be in the IM-yes group (p=0.0004 and 0.00175, respectively). Although there was a trend toward a better outcome in the IM-no group, there were no significant differences between the IM-yes and IM-no groups with respect to OS (73% IM-yes vs. 74% 1M-no, p>0.5), BRFS (84% IM-yes vs. 87% IM-no, p=0.305), or DMFS (75% IM-yes vs. 80% IM-no, p=0.095). Subset analysis showed no benefit in the IM-yes group regardless of age, number of nodes, or location. Conclusion: In this retrospective analysis, no benefit could be attributed to IMCR in conservatively treated patients even in patients with medial tumors and/or node positive disease. Until the results of an ongoing EORTC randomized trial addressing this issue are available, we will not intentionally target the internal mammary lymph nodes in conservatively managed breast cancer patients.
2038 CT ASSESSMENT OF SUPRACLAVICULAR AND INTERNAL MAMMARY LYMPH NODE DEPTH FOR ADJUVANT RADIA~ON OF BREASTCANCER Anne R. McCall, M.D., Mary Olson, M.D.* and Matthew Krasin, M.D. Depar~nents of Radiotherapy and *Radiology, Loyola University Medical Center Purpose: Several recent randomized trials have demonstrated a survival advantage with adjuvant regional nodal irradiation in women with breast cancer after mastectomy, yet the benefits in high risk women treated with breast preservation remain controversial. This study determined the depth of supraclavicular and internal mammary lymph nodes in 50 women and used CT-based treatment planning to determine the dose to these nodal areas using current treatment recommendations. Methods: The computerized tomograms (CT's) of 50 consecutive adult women were evaluated. The depth of the supraclavicular nodes were measured at the anterior border of the C7 vertebral body. The depth of the internal mammary lymph nodes were determined at the refleefion of the parastemal pleura in the 3rd intercostal space. The dose to the nodes at various depths were compared to isodose curves using standard published techniques, Results: The supraclavicular lymph nodes ranged in depth from 3.1 to 10.5 cm, with a median of 5.0 cm and an average depth 0f5.2 cm. If"standard" treatment was prescribed, giving 50 Gy to a depth of 3 cm using 6 mv photons, 52% of the patients would receive less than 90% of the prescribed dose and 22% would receive less than 85% of the desired dose to the supraclavicular nodes.. The depth of the internal mammary nodes ranged from 1.2 cm to 7.0 cm, with a median of 2.5 cm and an average depth of 2.9 cm. If "standard" treatment was prescribed giving 50 Gy to a depth of 4 cm using mixed photons and electrons, 68% of the patients would have the dose prescribed at least 1 cm deeper than appropriate, potentially risking underlying heart and lung to excessive treatment. Conclusion: "Standard" dose prescriptions for regional lymphatic radiation in women with breast cancer can result in many patients receiving inadequate dose to the supraclavicular lymphatics and may cause significant unnecessary dose beneath the internal mammary lymph nodes. All women who are given adjuvant radiation to regional lymphatics should undergo CT-based treatment planning to assure adequate coverage of target volumes. Results of clinical trials need to be evaluated in light of the adequacy of each trial's radiation techniques.