Young women are more likely than older ones to be diagnosed with more aggressive forms of breast cancer, but their outcomes can be good if they follow recommended treatments.

That is the take-home messages of two studies presented at the recent ESMO Breast Cancer Congress 2019, held in Berlin, according to Matteo Lambertini, a spokesperson from the European Society for Medical Oncology (ESMO).

“Women under 40 years of age tend to be diagnosed with more aggressive breast cancer types — for example their tumors are more likely to be triple negative and HER2 positive. Despite this, survival and local recurrence rates are similar to those of the general population of breast cancer patients provided they receive appropriate treatment,” Lambertini, also a medical oncologist at the IRCCS Policlinico San Martino Hospital, University of Genoa, Italy, said in a press release.

The first study, titled “Breast Cancer in Young Women — a multi-center 10-year experience,” was presented in a poster session by Ines Eiriz, MD, from the Hospital Prof. Doutor Fernando Fonseca, in Portugal.

In this study, researchers analyzed tumor incidence, aggressiveness, treatment response, and survival in a group of 207 Portuguese women under age 35 who had been diagnosed with breast cancer between 2008 and 2017.

Study findings revealed that almost all patients (91%) had been diagnosed with invasive ductal carcinoma, the most common type of breast cancer. Tumor subtype analyses showed that 20% of the tumors were triple-negative, 28% were HER2-positive, 67% were luminal B, and only 4% were luminal A. This confirms the high incidence of more aggressive forms of breast cancer among young women.

After a median follow-up period of 53.5 months, 26 women had developed breast cancer metastasis, in which the cancer spreads to other regions of the body, and three experienced local cancer recurrence. By the end of the study, 85% of the patients were still alive.

“Disease-free survival was longest in women with hormone receptor positive tumors [luminal A and B tumors], followed by those with HER2 positive disease, and lastly those with triple negative breast cancer. The median survival of patients without metastases was 130 months compared to 37 months for those with metastatic disease,” Eiriz said.

“Due to more aggressive biology, initial staging and survival, the group of very young women with breast cancer deserves special treatment approaches,” the researchers said in the study abstract.

The second study, “Breast cancer early recurrences in young women,” was presented in a poster session by Simona Cima, MD, from the IOSI — Oncology Institute of Southern Switzerland.

In this retrospective study, investigators assessed the rates of breast cancer recurrence among 359 women under 50 years old. All had been diagnosed with stage I to stage III invasive breast cancer, and received treatment from 2010 to 2017.

Study findings showed that, after a median follow-up period of 46 months, 29 women (7.6%) had breast cancer relapses. Among those 29, six women developed cancer metastases, 14 experienced local cancer recurrence, and nine developed both. The median time to cancer recurrence was 31 months.

Risk analyses showed the three-year risk for local cancer recurrence was 4.7%, while the five-year risk was 9.5%. Meanwhile, the rates of cancer-free survival were 94.3% at three years, and 91.2% at five years.

“Most recurrences in these patients were local rather than metastatic [and did not differ from those reported in the literature]. Our study is ongoing, and the next step is to identify predictors of local recurrence. For example, we will examine the likelihood of local recurrence according to HER2 and triple negative status,” Cima said.

ESMO’s Lambertini said the studies showed that young age alone is not a reason to give more intensive treatment.

“It’s not true that being diagnosed with breast cancer at a young age means poorer survival or higher chances of the cancer coming back, and these studies further confirm that. Proper guideline-recommended treatments should be given to all breast cancer patients regardless of their age. Special attention should be paid in these women on the potential side effects of anticancer therapies including the risk of infertility,” he said.