The incidence of @entity2 after surgery for XXXX with and without postoperative radiotherapy. Results of National Surgical Adjuvant Breast and Bowel Project (NSABP) clinical trials B-04 and B-06.

@entity1 @entity0 @entity5 @entity2 @entity717
BACKGROUND: In the current study, the authors compared the incidence of subsequent primary @entity2 in @entity1 with @entity0 who received radiotherapy as part of their treatment and in those @entity1 who did not. The @entity1 were @entity1 in two large National Surgical Adjuvant Breast and Bowel Project (NSABP) @entity0 trials, B-04 and B-06, which prospectively randomized @entity1 to either undergo surgery alone or to undergo surgery and postoperative radiotherapy. METHODS: The NSABP trial B-04 (1971-1974) randomized @entity1 to undergo radical mastectomy versus total (simple) mastectomy and radiotherapy to the chest wall, axilla, and supraclavicular and internal mammary lymph node areas. For @entity1 with a clinically uninvolved axilla, there was a third randomization arm: total mastectomy without radiotherapy. The B-06 trial (1976-1984) randomized @entity1 between those undergoing total mastectomy versus lumpectomy versus those undergoing lumpectomy and breast irradiation, with all @entity1 undergoing an axillary lymph node dissection. The records of all @entity1 who developed a recurrence in the lung or a new primary @entity2 were reviewed to determine the incidence and laterality of confirmed and probable primary @entity2 . RESULTS: For the 1665 evaluable @entity1 on the NSABP B-04 trial (mean follow-up of 21.4 years), there was a total of 23 subsequent confirmed and probable @entity2 . In those @entity1 who had received comprehensive postmastectomy radiotherapy, there was a statistically significant increase in the incidence of these new @entity5 (P = 0.029). With regard to the development of confirmed new primary @entity2 alone, the incidence was statistically significantly increased (P = 0.013) in those @entity1 who had received radiotherapy as part of their treatment, and when confirmed and probable @entity2 were analyzed, there was a strong trend toward a statistically significant increase in those @entity1 who had received radiotherapy (P = 0.066). For the 1850 evaluable @entity1 on the NSABP trial B-06 (mean follow-up of 19.0 years), there was a total of 30 second @entity2 but no increase in either @entity717 of the lung in those @entity1 who had received radiotherapy. CONCLUSIONS: Extensive postmastectomy irradiation of the chest wall and regional lymphatic node areas, with consequent exposure of a greater volume of lung to higher doses as administered in the NSABP B-04 trial compared with postlumpectomy breast irradiation in the NSABP B-06 trial, was associated with an increased incidence of subsequent primary @entity2 , both ipsilateral and contralateral.
