A review of treatment options in HER2-low breast cancer and proposed treatment sequencing algorithm

The expansion of the spectrum of human epidermal growth factor receptor 2 (HER2)-status to HER2-low, defined as HER2 expression of 1+ by immunohistochemistry (IHC) or 2+ by IHC without gene amplification, has made a major impact in the field of oncology. The HER2-low expression has emerged as a targetable biomarker, and anti-HER2 antibody-drug conjugate trastuzumab deruxtecan has shown significant survival benefit in pretreated metastatic HER2-low breast cancer (BC). With these recent data, the treatment algorithm for hormone receptor-positive and triple-negative BC needs to be reconsidered, as approximately half of these BCs are HER2-low. Although there are different therapeutic agents for hormone receptor-positive and hormone receptor-negative HER2-low BCs, there is no consensus regarding the sequencing of these agents. In this article, the treatment options for HER2-low BC are enumerated and a treatment sequencing algorithm based on the current clinical evidence proposed.

Impact of neoadjuvant chemotherapy on pathological stage and survival in sarcomatoid bladder cancer

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Background: Sarcomatoid bladder cancer is an extremely rare and aggressive histological variant with poor prognosis and limited consensus regarding its management given rarity and lack of high-quality data. Radical cystectomy (RC) is the mainstay of treatment in muscle-invasive disease and adjuvant therapy is often offered to eligible patients with high-risk features. Data regarding the role of neoadjuvant chemotherapy (NAC) for this variant is limited. Methods: The National Cancer Database was queried to identify patients diagnosed with sarcomatoid bladder cancer from 2004 to 2018. Patients older than 18 years with cT2-4aN0-1M0 sarcomatoid bladder cancer who received curative-intent surgery were included in the analyses. Clinical T4b/N2-3/M1 disease and receipt of adjuvant chemotherapy were employed as exclusion criteria. The population was divided into two cohorts based on the receipt of NAC. Chi-Square and Mann Whitney U tests were used to compare frequency distributions. Cox Proportional Hazards regression was employed to adjust for confounding factors associated with overall survival. Models were adjusted for age, race, sex, income, stage, insurance status, and the Charlson Comorbidity Index. Results: A total of 573 patients were identified - 70% were males and 93% were White; 139 (25%) received NAC (NAC+) while 434 (75%) did not (NAC-). NAC+ patients were younger (65 vs 71 years, p < 0.001). Downstaging to pT0-1N0 at the time of RC was significantly more frequent in the NAC+ group compared to the NAC- group (32 (24.5%) vs. 28 (6.8%), p = 0.001). Overall survival (OS) was also significantly longer in the NAC+ group (median of 40.8 vs. 19.4 months, log-rank p = 0.003). On multivariable analysis, NAC+ (Hazard Ratio (HR) = 0.73, 95% CI 0.56-0.91, p = 0.02), pathological downstaging to pT0-1N0 (HR = 0.5, 95% CI 0.31- 0.8, p < 0.001), and any pathological upstaging (HR 4.1, 95% CI 1.5-6.6, p < 0.001) were independently associated with all-cause mortality, while other factors were not (Table). Conclusions: In this large retrospective analysis, administration of NAC in muscle-invasive sarcomatoid bladder cancer was associated with higher rates of downstaging to non-muscle-invasive disease at the time of RC and reduced all-cause mortality. [Table: see text]

Radical nephroureterectomy followed by adjuvant chemotherapy (RNU-AC) versus observation (RNU-O) in early-stage upper urinary tract cancers with variant histology (UUTC-VH)

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Background: Upper urinary tract cancers (UUTC) are less frequent and associated with poorer stage-for-stage prognosis compared to bladder cancer, with variant histology being an independent predictor of inferior outcomes. The POUT trial included only patients with predominantly urothelial tumors. We aimed to compare outcomes among patients with UUTC-VH who were treated with RNU-AC vs. RNU-O. Methods: We queried the National Cancer Database for adult patients with UUTC-VH diagnosed between 2004 and 2018. Only patients who underwent RNU with node-negative disease on pathological staging (pT2-4N0M0) were included and divided into two groups based on the postoperative treatment strategy - RNU-AC and RNU-O. Patients who received neoadjuvant chemotherapy were excluded from analyses. Fisher’s exact and Mann Whiney U tests were used to compare frequency distributions. Cox Proportional Hazards regression was employed for multivariate analysis of factors associated with overall survival. Models were adjusted for age, sex, race, income, educational level, clinical T stage, insurance status, and the Charlson Comorbidity Index. Results: A total of 522 patients were identified – 133 (25.5%) received RNU-AC while 389 (74.5%) underwent RNU-O. Patients in the RNU-AC group were younger (median 69 vs. 76 years, P <0.001). Patients with small cell (15.8% vs 4.9%), micropapillary (9.8% vs 5.9%) and adenocarcinoma (9% vs 6.7%) histologies were more likely while those with squamous histology was less likely to receive AC (38.3% vs 50.6%) (p < 0.001 for all comparisons). A significant majority of patients in each T stage were treated with AC – 87.1% of pT1, 73.2% of pT2, and 68.4% of pT3 (P = 0.009). Overall survival in the RNU-AC and RNU-O groups were comparable (median of 27 vs 24.1 months, log rank-P = 0.63). On multivariable analysis, neither AC nor histological subtype were not independently predictive of OS (HR for AC = 0.96, 95% CI 0.74-1.24, P = 0.75). Conclusions: This is the largest study to date evaluating outcomes with AC after RNU in UUTC-VH since these patients were largely excluded from AC clinical trials. We observed that AC was not associated with improved overall survival after RNU in this population.

Neoadjuvant chemotherapy plus radical cystectomy (NAC-RC) versus trimodality therapy (TMT) in early-stage small cell bladder cancer: Comparison of outcomes

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Background: Small cell bladder cancer is a rare and aggressive histological variant with a paucity of data to guide the optimal management strategy in non-metastatic disease. NAC-RC and TMT (maximal transurethral resection of bladder tumor + chemoradiation) have been variably employed based on institutional preferences, and we aim to compare outcomes between these two approaches. Methods: We queried the National Cancer Database for adult patients with small cell bladder cancer diagnosed during the years 2004 to 2018. Patients with small cell histology and early-stage clinically node-negative bladder cancer (cT1-4N0M0) were included and divided into two groups based on the treatment strategy employed – NAC-RC or TMT. Patients who did not receive any definitive local therapy and those who received chemotherapy or radiation in the adjuvant setting were excluded. Fisher’s exact and Mann Whiney U tests were used to compare frequency distributions. Cox Proportional Hazards regression was employed for multivariate analysis of factors associated with overall survival. Models were adjusted for age, sex, race, income, educational level, clinical T stage, insurance status, and the Charlson Comorbidity Index. Results: A total of 1262 patients were identified – 629 (49.8%) underwent NAC-RC while 633 (50.2%) received TMT. Patients in the NAC-RC group were younger (median 67 vs. 74 years, P <0.001) and more frequently Males (81% vs 76%, p = 0.02). Clinical T stage was comparable between the groups (P = 0.38). Patients with private insurance (P < 0.001) and higher income tiers (P = 0.04) were more likely to receive NAC-RC in lieu of TMT. Overall survival in the NAC-RC group was significantly longer than the TMT group (median of 41.3 vs. 25.4 months, log-rank P < 0.001). On multivariable analysis, only the type of treatment modality employed was independently predictive of overall survival (Hazard Ratio of 1.22 for TMT, with 95% CI 1.05-1.43, P = 0.01). Conclusions: In early-stage clinically node-negative small cell bladder cancer, NAC-RC was associated with significantly longer overall survival compared to TMT.

Pembrolizumab (Pem) in metastatic castration-resistant prostate cancer (mCRPC): Experience from a comprehensive cancer center

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Background: The prognosis of refractory mCRPC remains poor despite advancements in therapeutic options. KeyNote-199 demonstrated modest activity of Pem in mCRPC with expected safety profile. We present our real-world experience with Pem in mCRPC. Methods: We conducted a retrospective review of mCRPC patients treated with Pem at our institution from 1/1/2017 to 10/1/22. Baseline demographic, clinicopathologic, and genomic characteristics were recorded. PSA and radiographic responses were assessed by the study team, and survival distributions estimated using the Kaplan-Meier method. Results: A total of 39 patients were identified – 97% (37) were White, median age was 71 years, 4% (19/35) had a Gleason Score ≥8; 80% (31) had skeletal and 74% (29) had soft tissue metastases at Pem initiation. Overall, patients were heavily pre-treated (median of 7 prior therapies, range 0-8) - 87% (34) had received taxanes, 82% (32) novel antiandrogens, 23% (9) Ra-223, 21% (8) Sipuleucel-T, and 2% (1) Olaparib. Median duration on Pem was 7 months (range = 1-29). Among the 34 evaluable patients, 2 (6%) achieved CR, 2 (6%) had PR, 5 (15%) had stable disease (SD), and 25 (73%) had progressive disease (PD) on radiographic assessment. PSA reduction ≥ 50% was noted in 7/32 (22%) patients. The 4 patients who had radiographic CR/PR had positive predictive biomarkers – Patient 1: CR – MSI-H, high TMB (17.5/Mb); Patient 2: CR – MSI-indeterminate, germline MSH6 mutation; Patient 3: PR – MSI-H, high TMB (28.8/Mb), germline MSH2 mutation; and Patient 4: PR – MSI-S, high TMB (18.3/Mb), PDL1 TPS 100%, positive neuroendocrine markers. Interestingly, patient 3 was switched to ipilimumab + nivolumab after PD on Pem, and subsequently had a CR. None of the evaluated patients with SD or PD had high MSI, TMB, or PDL1 levels. The median overall survival from Pem initiation was 4.4 months (95% CI 3.0-10.2 months). Three (8%) patients discontinued Pem due to immune-related adverse effects (IRAEs); no treatment-related deaths were reported. The most frequent Gr 3 IRAEs are shown. Conclusions: Single-agent Pem demonstrated modest overall efficacy in mCRPC, restricted only to patients with predictive biomarkers. Given the non-trivial risk of IRAEs, financial toxicity, and potential QoL implications, we suggest using checkpoint inhibitors only in appropriately biomarker-selected patients with mCRPC. [Table: see text]

Neoadjuvant chemotherapy (NAC) versus adjuvant chemotherapy (AC) in patients with clinically node-positive upper tract urothelial cancer (UTUC) who underwent radical nephroureterectomy (RNU)

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Background: UTUC is less common and associated with poorer stage-for-stage prognosis compared to urothelial bladder cancer. AC is regarded as a standard-of-care in high-risk UTUC based on superior disease-free survival compared to observation in the POUT trial, though fewer than 10% of patients in this trial had lymph node involvement.1 CheckMate 274 revealed lesser magnitude of benefit with adjuvant nivolumab in UTUC compared to bladder cancer on post hoc analysis.2 The preferred sequence of perioperative systemic therapy in node positive UTUC remains unclear. Methods: We queried the National Cancer Database for adult patients with clinically node positive (cTanyN1-3M0) UTUC diagnosed between 2004 and 2018. Patients were divided into two groups based on the perioperative treatment strategy - NAC or AC. Patients who did not undergo RNU were excluded from analyses. Fisher’s exact and Mann Whiney U tests were used to compare frequency distributions. Cox Proportional Hazards regression was employed for multivariate analysis of factors associated with overall survival. Models were adjusted for age, sex, race, income, educational level, clinical T stage, insurance status, and the Charlson Comorbidity Index. Results: A total of 862 patients were identified - 362 (42%) underwent NAC while 500 (58%) received AC. No significant differences were noted between the groups regarding age, sex, or insurance status. Patients with cT1-2 UTUC more often received NAC (27.9% vs 11.8%, P <0.001) while those with cT3-4 disease more frequently received AC (38.9% vs 57.4%, p<0.001). Rates of NAC vs AC were not significantly different based on clinical N stage (P = 0.35). Overall survival in the NAC group was significantly longer than the AC group (median of 47.1 vs. 20.2 months, log-rank P < 0.001). On multivariable analysis, only the sequence of perioperative chemotherapy was independently predictive of overall survival (Hazard Ratio of 1.38 for AC, with 95% CI 1.14-1.68, P = 0.001). Conclusions: In this large retrospective analysis of outcomes among patients with clinically node positive UTUC who underwent RNU, NAC was associated with significantly longer overall survival compared to AC. References: 1) Birtle A, Lancet 2020; 2) Bajorin DF, NEJM 2021.