Published online Feb 6, 2020. doi: 10.12998/wjcc.v8.i3.517
Peer-review started: December 5, 2019
First decision: December 23, 2019
Revised: January 9, 2020
Accepted: January 15, 2020
Article in press: January 15, 2020
Published online: February 6, 2020
Processing time: 62 Days and 18.8 Hours
Pathological complete response (pCR) is rare in hormone receptor-positive (HR+) HER2-negative breast cancer (BC) treated with either endocrine therapy (ET) or chemotherapy. Radical resection of locoregional relapse, although potentially curative in some cases, is challenging when the tumor invades critical structures. The oral cyclin-dependent kinase 4/6 inhibitor palbociclib in combination with ET has obtained a significant increase in objective response rates and progression-free survival in patients with advanced BC and is now being evaluated in the neoadjuvant setting. We present a clinical case of a patient with an inoperable locoregional relapse of HR+ HER2-negative BC who experienced pCR after treatment with palbociclib.
We report the clinical case of a 60-year-old patient who presented with an inoperable locoregional relapse of HR+, HER2-negative BC 10 years after the diagnosis of the primary tumor. During a routine follow-up visit, breast magnetic resonance imaging and positron emission tomography/computed tomography revealed a 4-cm lesion in the right subclavicular region, infiltrating the chest wall and extending to the subclavian vessels, but without bone or visceral involvement. Treatment was begun with palbociclib plus letrozole, converting the disease to operability over a period of 6 mo. Surgery was performed and a pCR achieved. Of note, during treatment the patient experienced a very uncommon toxicity characterized by burning tongue and glossodynia associated with dysgeusia, paresthesia, dysesthesia, and xerostomia. A reduction in the dose of palbociclib did not provide relief and treatment with the inhibitor was thus discontinued, resolving the tongue symptoms. Laboratory exams were unremarkable. Given that this was a late relapse, the tumor was classified as endocrine-sensitive, a condition associated with high sensitivity to palbociclib.
This case highlights the potential of the cyclin-dependent kinase 4/6 inhibitor plus ET combination to achieve pCR in locoregional relapse of BC, enabling surgical resection of a lesion initially considered inoperable.
Core tip: The rate of pathological complete response after endocrine therapy in hormone receptor-positive breast cancer is low, limiting the value of pathological complete response as a surrogate endpoint for the effectiveness of this treatment. Moreover, radical resection of locoregional recurrence is difficult to achieve when the tumor invades critical structures, e.g., blood vessels. Several studies have evaluated whether endocrine therapy could also be used as a research platform for testing novel drugs in patients with ER-positive disease.