Chronic Pain Common After Breast Cancer Surgery

By: Michael Vlessides

From: generalsurgerynews.com

Chronic postsurgical pain after breast cancer surgery is common, affecting approximately one in every three women undergoing the procedure.

That is the conclusion of a systematic review and meta-analysis, whose investigators found that almost half of these patients will report at least moderate pain, and with more than one in 10 reporting severe pain.

“Chronic pain after breast cancer surgery is obviously a big problem,” said Yvgeniy Oparin, MD, a resident at McMaster University, in Hamilton, Ontario. “Previous systematic reviews [Breast 2018;42:113-127] have examined this prevalence, but had a number of limitations. Of these, the search protocol wasn’t updated, so it didn’t include more recent trials. In addition, it looked at both randomized controlled trials as well as prospective cohort studies and observational trials, so it didn’t really capture the natural progression of these patients postsurgically.”

Pain Extends Beyond 4 Years in Some

To address these limitations, Dr. Oparin and his colleagues examined the prevalence of postsurgical pain after breast cancer surgery. “We only included studies with a hundred or more patients that captured pain at three months or longer,” Dr. Oparin said.

he investigators searched a variety of relevant databases, from inception through October 2018. The search was designed to identify observational studies reporting the prevalence and intensity of chronic postsurgical pain after breast cancer surgery. They used random-effects models for overall pain, neuropathic pain, and the prevalence of moderate to severe pain, as well as pooled pain intensity after converting all pain scales to a 10-cm visual analog scale (VAS).

In total, 184 observational studies were included in the analysis, comprising 298,549 patients. The average sample size was approximately 300 patients per study.

As Dr. Oparin reported at the 2019 annual meeting of the Canadian Anesthesiologists’ Society (abstract 637841), the overall prevalence of any chronic postsurgical pain was found to be 34.8% (95% CI, 30.2%-39.5%). For moderate pain, the prevalence was 14.9% (95% CI, 11.5%-18.7%), and for severe pain it was 4% (95% CI, 2.7%-5.5%).

Chronic postsurgical pain prevalence was present in 36.2% of patients between three months and one year after surgery (95% CI, 29.5%-43.2%); 33.7% between one and two years post-op (95% CI, 15.3%-55.1%); 26.6% between two and four years (95% CI, 11.3%-45.5%); and 36.6% at four years or later (95% CI, 21.1%-53.7%).

“So it seems like these patients aren’t really getting better,” Dr. Oparin said. “Once you get the pain postsurgically, it seems like you’re stuck with it.”

Of those who developed persistent pain, 43% reported at least moderate pain, whereas 12% experienced severe pain. Nevertheless, the average VAS pain intensity was 2.7 (95% CI, 2.2-3.1). The analysis also found that the prevalence of neuropathic pain was 33.7% (95% CI, 22%-46.5%).

Axillary Dissection Versus Sentinel Biopsy

“Did you examine anything with respect to the treatment of pain?” asked Karim Ladha, MD, an assistant professor of anesthesia at the University of Toronto.

“We wanted to examine the natural progression postsurgically, which is why we were looking specifically at prospective cohort and cross-sectional studies,” Dr. Oparin said.

“Did you differentiate between whether patients had axillary node dissection or not?” asked another audience member.

“We did perform some subgroup analyses,” Dr. Oparin replied. These analyses revealed that 45% of women who underwent axillary lymph node dissection experienced chronic postsurgical pain, compared with 28% of those who underwent sentinel lymph node biopsy.

“This is an excellent systematic review,” commented session moderator Jonathan Bailey, MD, an assistant professor of anesthesia, pain management and perioperative medicine at Dalhousie University, in Halifax, Nova Scotia. “I was impressed by the sheer number of studies you included, as well as the number of studies that went out to four years and beyond.

“Nevertheless,” Dr. Bailey added, “there’s a fair amount of heterogeneity in the data, which you’re probably going to expect in any pain study, depending on what the treatment is.”