Abstract

Fadoua Rais¹, James Man Git Tsui¹, Mame Daro Faye¹, Alyssa Daianska¹, Christine Lambert¹, Marc David¹, Valerie Panet-Raymond¹, Melissa Azoulay¹, Asma Saidi¹, Tarek Hijal¹

¹McGill University Health Centre, Cedars Cancer Centre., Radiation-oncology, Montreal, Canada

Breast cancer locoregional (LR) radiation in the elderly requires careful consideration between the benefits of aggressive treatment and its potential toll on elderly patients. Extreme weekly LR hypofractionated radiation (HFRT), defined as a fractionation regimen delivering more than 5 Gy per fraction, given weekly, is a treatment option that may be better suited in such a population. It represents a good compromise between omitting and exhaustive daily radiation over several weeks, especially in frail and elderly women. It is also a less cumbersome therapeutic alternative that would offer similar efficacy with comparable or lower toxicity rates. This study aims to report the local and LR control rate as well as the acute and long-term side effects of the elderly patients treated with HFRT in our institution, and to compare these results to those from the literature.

We conducted a retrospective study by reviewing medical records of elderly patients with breast cancer treated with adjuvant once-weekly LR HFRT in our institution between 2011 and 2020. Fifty patients presenting with primary non-metastatic breast tumors (Stage I–III) were included. Treatment outcomes including local/LR control, distant metastasis, cause-specific survival, and overall survival were reported. Early and late toxicity profiles were also assessed. 

After a median follow-up of 4.8 years, only one local recurrence in the chest wall occurred and there was no regional recurrence. The distant metastatic rate was 6%. The long-term recurrence-free survival (RFS) rate was 80% at 5 years. The cause-specific survival rate was 90% at 5 years.  The overall survival rate was 55.5% at 5 years. There were 44 (88%) patients with Grade 1 or 2 early toxicity, consisting mainly of dermatitis. There was no Grade 3 or higher acute toxicity registered. Late toxicity was mainly Grade 1 or 2 subcutaneous fibrosis, lymphoedema, and neuropathy except for one patient with Grade 3 fibrosis.

Figure legends

Figure 1: Overall survival (OS) of elderly patients treated with LR HFRT OS was calculated from time of radiotherapy start to time to time of death. Median follow-up time was 4.8 years. 

Figure 2: Recurrence-free survival (RFS) and Cancer-specific survival (CSS) of elderly patients treated with LR HFRT Local/ locoregional failure (LRF), distant metastasis (DM) and death events were retrospectively recorded. RFS and CSS were calculated from time of radiotherapy start to time when first event recorded. Median follow-up time was 4.8 years.

Extreme LR HFRT is well tolerated with good outcomes and is a good alternative treatment for elderly and frail patients. Our results confirm the efficacy and safety of such a regimen in the setting where LR radiation is needed. Further randomized controlled trials (RCTs) assessing both oncologic outcome and toxicity profile are justified.