Journal of Cancer Research and Therapeutics

LETTER TO THE EDITOR
Year
: 2022  |  Volume : 18  |  Issue : 3  |  Page : 864--865

FAST-Forward in breast radiotherapy: Really fast, but how much forward?


Anusheel Munshi, Khushboo Rastogi 
 Department of Radiation Oncology, Manipal Hospital, New Delhi, India

Correspondence Address:
Anusheel Munshi
Department of Radiation Oncology, Manipal Hospitals, Dwarka, New Delhi
India




How to cite this article:
Munshi A, Rastogi K. FAST-Forward in breast radiotherapy: Really fast, but how much forward?.J Can Res Ther 2022;18:864-865


How to cite this URL:
Munshi A, Rastogi K. FAST-Forward in breast radiotherapy: Really fast, but how much forward?. J Can Res Ther [serial online] 2022 [cited 2022 Sep 28 ];18:864-865
Available from: https://www.cancerjournal.net/text.asp?2022/18/3/864/347793


Full Text



Sir,

The recent article of “FAST-Forward” in breast cancer has aroused significant interest.[1] Brunt et al. report that, for early-stage breast cancer, a dose of 26 Gy in five fractions over 1 week for breast radiotherapy is noninferior to the existing standard of 40 Gy in 15 fractions over 3 weeks for local tumor control and is safe in terms of normal tissue effects up to 5 years. These findings appear promising and potentially practice changing. On a closer look, however, areas of concern remain.

The authors have supposedly included patients undergoing breast conservation or mastectomy, but the numbers (approximately 93% for conservation vs. 6.5% for mastectomy) suggest a very low representation of mastectomy cases. This also leaves the question of this regimen's applicability and safety for regional nodal irradiation unanswered. For the 15 fractions schedule, the question related to its use in postmastectomy scenario was answered only by Wang et al., who randomized postmastectomy patients to hypofractionated radiotherapy (43·5 Gy in 15 fractions over 3 weeks) versus conventional treatment (50 Gy in 25 fractions over 5 weeks).[2] They reported no difference in 5-year cumulative incidence of locoregional recurrence (8·3% in the hypofractionated radiotherapy group vs. 8·1% in the conventional fractionated radiotherapy group) which was reassuring and paved a way for use of these 15 fraction regimens for patients requiring local/regional radiotherapy. The investigators of FAST-Forward should have either included more postmastectomy cases in this study or confined it purely to breast conservation cases only.

The laxity allowed by lead investigators for boost use is concerning and surprising.[3] This unfortunately has been consistently visible in previous trials of the group (START A, START B) as well.[4] In the Fast-Forward trial, it is evident that sequential tumor bed boost was “allowed” (but not mandatory) to a dose of 10–16 Gy. Only 25% of the patients received a breast boost. This leaves the reader wondering about the actual boost strategy to be used in his clinic while using the Fast-Forward regimen.

The FAST-Forward trial has included patients of early-stage breast cancer (T1-3, N-1, M0). However, it actually only represents pathological stage pT1 (approximately >70%) and pN0, with >80% of patients being node negative. As such, the results of the trial are largely applicable only to pT1pN0 breast cancer patients, something which the authors of the study have not duly highlighted. This favorable population in fact is the primary reason for the very low primary end point events reported across all arms in the study. It is likely that a large proportion of the study subjects would fit the criteria for accelerated partial breast irradiation or be candidates for no adjuvant radiotherapy at all.

Overall, while the trial represents an advance in breast cancer radiotherapy, it brings forth several questions too. While hypofractionated radiotherapy in breast cancer is here to stay, the final word is still some distance away.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

References

1Murray Brunt A, Haviland JS, Wheatley DA, Sydenham MA, Alhasso A, Bloomfield DJ, et al. Hypofractionated breast radiotherapy for 1 week versus 3 weeks (FAST-Forward): 5-year efficacy and late normal tissue effects results from a multicentre, noninferiority, randomised, phase 3 trial. Lancet 2020;395:1613-26.
2Wang SL, Fang H, Song YW, Wang WH, Hu C, Liu YP, et al. Hypofractionated versus conventional fractionated postmastectomy radiotherapy for patients with high-risk breast cancer: A randomised, noninferiority, open-label, phase 3 trial. Lancet Oncol 2019;20:352-60.
3Munshi A, Budrukkar A. Hypofractionated radiation therapy in breast cancer: A revolutionary breakthrough or a long way to go? J Clin Oncol 2007;25:458-9.
4Haviland JS, Owen JR, Dewar JA, Agrawal RK, Barrett J, Barrett-Lee PJ, et al. The UK Standardisation of breast radiotherapy (START) trials of radiotherapy hypofractionation for treatment of early breast cancer: 10-year follow-up results of two randomised controlled trials. Lancet Oncol 2013;14:1086-94.