Optimising adjuvant breast radiotherapy via preoperative imaging

Historically, even early-stage breast cancer required exceedingly aggressive locoregional treatment. Nowadays, it is among the most curable of malignancies, necessitating increasingly limited intervention. Landmark surgical trials showed that breast-conserving surgery (BCS; also known as lumpectomy) was not a suitable alternative to mastectomy unless it was bolstered by adjuvant radiotherapy. 1 Fisher B Anderson S Bryant J et al. Twenty-year follow-up of a randomized trial comparing total mastectomy, lumpectomy, and lumpectomy plus irradiation for the treatment of invasive breast cancer. N Engl J Med. 2002; 347: 1233-1241 Crossref PubMed Scopus (5032) Google Scholar As this combined-modality approach (lumpectomy with radiotherapy) became more widely adopted, several studies revisited the requirement for adjuvant radiotherapy over the years. 2 Fyles AW McCready DR Manchul LA et al. Tamoxifen with or without breast irradiation in women 50 years of age or older with early breast cancer. N Engl J Med. 2004; 351: 963-970 Crossref PubMed Scopus (586) Google Scholar , 3 Lim M Bellon JR Gelman R et al. A prospective study of conservative surgery without radiation therapy in select patients with stage I breast cancer. Int J Radiat Oncol Biol Phys. 2006; 65: 1149-1154 Summary Full Text Full Text PDF PubMed Scopus (66) Google Scholar , 4 Fisher B Bryant J Dignam JJ et al. Tamoxifen, radiation therapy, or both for prevention of ipsilateral breast tumor recurrence after lumpectomy in women with invasive breast cancers of one centimeter or less. J Clin Oncol. 2002; 20: 4141-4149 Crossref PubMed Scopus (569) Google Scholar Many of these studies preceded our current understanding of biologically driven risk, and consequently exhibited inordinately high recurrence rates, further cementing the need for radiotherapy. More recently, trials such as CALGB 9343 5 Hughes KS Schnaper LA Bellon JR et al. Lumpectomy plus tamoxifen with or without irradiation in women age 70 years or older with early breast cancer: long-term follow-up of CALGB 9343. J Clin Oncol. 2013; 31: 2382-2387 Crossref PubMed Scopus (886) Google Scholar and PRIME II 6 Kunkler IH Williams LJ Jack WJL Cameron DA Dixon JM Breast-conserving surgery with or without irradiation in early breast cancer. N Engl J Med. 2023; 388: 585-594 Crossref PubMed Scopus (46) Google Scholar demonstrated the feasibility of omitting radiation for older patients with small, oestrogen receptor (ER)-positive tumours, albeit with a modestly increased risk of local recurrence, thus setting the stage for a series of ongoing trials that promise to widen the conditions under which patients can reasonably forego radiotherapy. 7 Braunstein LZ Incorporating tumor biology to select patients for the omission of radiation therapy. Surg Oncol Clin N Am. 2023; 32: 725-732 Summary Full Text Full Text PDF Scopus (0) Google Scholar Postoperative radiotherapy omission in selected patients with early breast cancer following preoperative breast MRI (PROSPECT): primary results of a prospective two-arm studyPROSPECT suggests that women with unifocal breast cancer on MRI and favourable pathology can safely omit radiotherapy. Full-Text PDF