An innovation in cancer treatment: Do we need proton beam therapy here?

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By Barbara Greenwood Dufour

There has been a lot of interest lately about a newer type of radiation therapy for treating cancer. Called proton beam therapy, or PBT, this treatment is thought to be a safer alternative to conventional photon therapy. Whereas a beam of photons directed at a tumour can also damage the healthy tissue around it, a proton beam is said to deliver more of its energy to the tumour, sparing the surrounding tissues. Reducing the “collateral damage” from radiation is an important consideration, especially when the tumour is close to critical tissues, such as the spinal cord and the brain, or in children, who are more sensitive than adults to radiation and therefore are at a higher risk of long-term side effects, including the development of secondary cancer.

Currently, Canadian patients are referred to facilities in the US for the treatment because, with the exception of a specialized research facility in Vancouver that uses PBT to treat intraocular melanoma, the technology isn’t available in Canada. Should it be, or should patients continue to be sent out of country for treatment? This question is important to consider carefully given that PBT is a very expensive technology. Constructing a PBT centre can cost from US$25 million to US$200 million, depending on the size and capacity of the facility.

To help answer the question, CADTH — an independent agency that finds, assesses, and summarizes the research on drugs, medical devices, tests, and procedures — recently conducted a health technology assessment of PBT. The CADTH review assessed the clinical effectiveness of the therapy and its associated harms compared with other types of radiotherapy. Is it effective and is it really safer?

The evidence suggests that PBT, alone or in combination with photon radiotherapy, might be as effective as other types of radiotherapy to treat most types of cancer. In terms of safety, PBT might be safer than other types of radiotherapy for some cancers but not for others. The evidence is limited, so we’re not sure. PBT is still a fairly new technology; therefore, there aren’t enough high-quality research results available yet to understand the benefits or harms of the treatment.

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As mentioned previously, because the technology looks like it could be a promising option for treating certain cancers, some Canadian cancer patients are being referred to PBT facilities in the US. There have been, however, several recent news stories that describe the hardship experienced by patients and their families when they have to travel far from the familiarity of their own country to receive PBT. To find out what the evidence says about the perspectives and experiences of patients who travel out of country to receive PBT, CADTH conducted a review of the available research on this topic as part of the health technology assessment. The literature CADTH identified found evidence suggesting that travelling to and staying away from home at a PBT centre is challenging in terms of being in an unfamiliar place and away from family. However, it also reveals a more nuanced picture of the upheaval, with many patients and the family members accompanying them finding some benefits in being in a new environment and being able to better focus on treatment and care.

Would Canadian patients benefit if a PBT facility were to be installed in Canada? Given the country’s vast geography, significant travel and relocation would be less for some patients but would still be required for many. Therefore, the experiences of patients and the people who accompany them for treatment are likely to be similar whether they are treated from within or outside the country. And, until there is more and better research available on the clinical effectiveness of PBT compared with other types of radiotherapy, it’s unclear whether the treatment they could receive at a PBT centre would be better than the conventional treatments that are already available closer to home. Careful consideration of all the factors — such as cost, effectiveness, and patient experiences and perspectives — can help when making decisions about whether to establish PBT in Canada.

If you’d like to learn more about CADTH and its review of PBT for the treatment of cancer, visit www.cadth.ca. You can also follow us on Twitter @CADTH_ACMTS or speak to a Liaison Officer in your region.

Barbara Greenwood Dufour is a Knowledge Mobilization Officer at CADTH.