Most Oncologists Discuss Drug Side Effects, Open to Reduce Doses

Roxanne Nelson, RN, BSN

December 15, 2021

Many patients with metastatic breast cancer (MBC) experience distressing toxicity related to treatment.

According to a new survey, all oncologists reported talking to their patients about side effects at every visit and nearly all (97%) were open to lowering medication doses.

The findings, presented during a poster session at the 2021 San Antonio Breast Cancer Symposium (SABCS), were encouraging to Charles Shapiro, MD, of the Icahn School of Medicine at Mount Sinai in New York City.

"I think this survey confirms that a lot of oncologists are willing to reduce the dose if patients have side effects, and a high percentage discuss side effects with their patients," said Shapiro, who was not involved in the study.

Anne L. Loeser, who has MBC and is co-author of the survey alongside a team of oncologists, agreed that it is vitally important for doctors to discuss toxicity and take patients' quality of life into consideration.

"Patients with MBC are incurable — albeit treatable — and the majority will remain on therapy for the rest of their lives," Loeser, founder of the Patient-Centered Dosing Initiative (PCDI), told Medscape Medical News. "Understandably, we want to make the most of the time we have left."

When patients begin treatment, oncologists often prescribe the recommended starting dose, which is based on the clinical trial results used to approve the drug. However, patient tolerance for this dose in the real-world setting often differs from that of clinical trial participants, the survey authors note.

In fact, Loeser said, "this dose generally precipitates the most, and worst, side effects."

In a previous survey, the team of researchers found that, among 1221 patients with MBC, 86% experienced at least one significant treatment-related side effect and almost all were willing to discuss individualized dosing with their physicians. The current study expands on that research, highlighting responses about treatment side effects and dosing options from medical oncologists.

In the new study, a confidential, 28-question online survey was sent to US medical oncologists identified via professional organizations, social media, and email lists. The objective of the survey was to gain a better understanding of oncologists' perspectives regarding the prevalence and severity of treatment-related toxicity, increase recognition of the impact of dosage-related mitigation strategies on clinical outcomes, and determine their willingness to discuss flexible dosing options.

A total of 119 medical oncologists participated in the survey. Of this group, 85% specialized in breast cancer, 66% worked in an academic setting, and 82% had been in practice for more than 5 years.

Overall, respondents estimated that nearly half of their patients had reported a distressing treatment-related side effect, 15% visited the emergency department or hospital for this reason, and 37% required a break from treatment. The most common mitigation strategies included prescribing supportive medication, offering suggestions for palliation, and lowering the medication dose.

All respondents reported reducing medication doses as a means of alleviating side effects; 74% reported that dose reduction helped relieve side effects; and 71% indicated that efficacy of the reduced dose was similar to that of the standard dose.

Notably, 60% of oncologists indicated that patients felt better when therapy began with a lower starting dose rather than the standard dose, and 59% indicated that treatment efficacy was similar to the standard dose. The drugs, or drug classes, most commonly prescribed at lower initial doses were capecitabine (91%), taxanes (60%), and palbociclib (50%).

The authors concluded that "these patient-centered dosing discussions should be part of routine care and may consequently improve [quality of life] for patients with MBC."

In the past, quality of life and quantity of life were perceived as an "either/or" proposition, but that mentality is changing, Loeser said. "In fact, the [US Food and Drug Administration] is moving away from the concept of maximum tolerated dose in favor of identifying the optimal dose with regard to safety and efficacy."

Loeser also noted that toxicity-related side effects not only affect quality of life, they also affect treatment options. These side effects "may force some patients to stop a working treatment prematurely," she said. In addition, "cumulative side effects that build up over successive treatments may preclude patients from [using] the full list of therapies available to them because they can no longer withstand the toxicities from further drugs."

Some survey participants also posted comments in the survey, elaborating on how they communicate with patients and manage treatment-related toxicities.

One oncologist emphasized the need for an individualized approach to dose adjustments: "Like other decisions, this requires good communication and an effort to understand patients' preferences and expectations, so that an informed decision can be made."

Another participant noted that "it is critical to be able to vary dose based on the individual, as well as the biology of their cancer. It is quite likely that lower doses are less effective in some cases, but this can be sorted out as treatment is ongoing."

For certain patients, dose reduction may not be the best option, one respondent said. "In some cases, it may be prudent to go a step further and move to best supportive care rather than reduce dose, particularly for late line therapy or indolent disease."

For Shapiro, establishing a strong partnership between physician and patient is critical to ensuring patients get the best care possible.

"You rely on patients to tell you what's working and what isn't with the drug, and we can make adjustments," he said. "It can be the greatest drug in the world, but if your patient can't tolerate it, then it isn't going to do much good."

The survey was conducted by PCDI. Loeser is the founder of the PCDI.

SABCS 2021. Abstract P4-10-09. Presented December 9, 2021

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