How Many Radiation Treatments Do I Really Need?

This is one of the most common questions patients ask during their first consultation.

Many people assume that all radiation treatments last the same amount of time. Others know someone who completed treatment in just five sessions and are surprised when they hear that their own treatment may take several weeks.

The reality is that the number of treatments depends on the type of cancer being treated.

There is no single “correct” number of radiation sessions that applies to everyone.

Years ago, most radiation therapy schedules were considerably longer than those used today. Over time, clinical trials demonstrated that for certain cancers, higher doses could be safely delivered during each treatment session, allowing the total number of visits to be reduced without compromising cancer control.

Breast cancer is a good example.

For decades, many women received approximately 25 radiation treatments. Later, studies such as START and FAST-Forward showed that shorter treatment schedules could provide equivalent outcomes in appropriately selected patients. Today, some women can complete their radiation therapy in as few as five treatments.

A similar evolution has occurred in prostate cancer.

For many years, radiation therapy was typically delivered in nearly 40 sessions. 

More recently, moderately hypofractionated schedules reduced treatment to approximately 20 to 28 sessions. Clinical trials such as PACE-B later demonstrated that some patients could receive stereotactic body radiation therapy (SBRT) in approximately five treatments while maintaining outcomes comparable to much longer schedules.

When a patient asks how many treatments are necessary, I usually try to reframe the discussion slightly.

The most useful question is often not how many treatments I will receive.

The more useful question is which treatment schedule has been shown to provide the best results for my specific cancer.

For some patients, the answer may be five treatments.

For others, twenty.

For others, twenty-eight.

And in certain situations, even more.

The length of treatment depends on several factors, including the diagnosis, tumor location, treatment goals, previous therapies, and the scientific evidence available for that particular disease.

That is why two patients treated in the same radiation center on the same day may receive completely different treatment schedules while both are receiving the most appropriate care for their situation.

What matters is not whether the treatment is the shortest or the longest.

What matters is receiving the schedule that has been shown to provide the best balance between effectiveness and safety for your particular cancer.

If I had to summarize this topic in a single sentence, it would be this:

The number of radiation treatments does not determine the quality of care. What matters most is receiving the treatment schedule that has been proven to work best for your type of cancer.

References

Murray Brunt A, Haviland JS, Wheatley DA, 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, Non-inferiority, Randomised, Phase 3 Trial. Lancet. 2020;395(10237):1613-1626. doi:10.1016/S0140-6736(20)30932-6

Haviland JS, Owen JR, Dewar JA, 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 Oncology. 2013;14(11):1086-1094. doi:10.1016/S1470-2045(13)70386-3

Brand DH, Tree AC, Ostler P, et al. Intensity-modulated Fractionated Radiotherapy Versus Stereotactic Body Radiotherapy for Prostate Cancer (PACE-B): Acute Toxicity Findings From an International, Randomised, Open-label, Phase 3, Non-inferiority Trial. Lancet Oncology. 2019;20(11):1531-1543. doi:10.1016/S1470-2045(19)30569-8

Morgan SC, Hoffman K, Loblaw DA, et al. Hypofractionated Radiation Therapy for Localized Prostate Cancer: Executive Summary of an ASTRO, ASCO, and AUA Evidence-Based Guideline. Practical Radiation Oncology. 2018;8(6):354-360. doi:10.1016/j.prro.2018.08.002