Efficacy and Safety of Bevacizumab Combined With First-Line Chemotherapy in Elderly (≥75 Years) Patients With Metastatic Colorectal Cancer: A Real-World Study

BACKGROUND

Although elderly patients are the first concerned by colorectal cancer (CRC), they are underrepresented in clinical trials. The real-world CASSIOPEE study was thus conducted in elderly patients treated for metastatic CRC (mCRC).

METHODS

This French prospective, multicenter, noninterventional study aimed to estimate 1-year progression-free survival (PFS) and overall survival (OS), and describe treatments, patient autonomy (Instrumental Activities of Daily Living; Balducci scale), and safety over 24 months, in patients older than 75 with mCRC, starting first-line bevacizumab plus chemotherapy (NCT01555762).

RESULTS

From 2012 to 2014, 402 patients were included (safety population: n = 383, efficacy population: n = 358). Patient characteristics were as follows: mean age, 81 ± 4 years (<80 years, 46%; 80-85 years, 44%; >85 years, 10%); men, 52%; colon primary tumor, 80%; main metastatic site, liver 66%; Eastern Cooperative Oncology Group performance 0-1, 81%. Median PFS was 9.1 months (95% confidence interval [CI]: 8.3-10.2). It was superior for patients ≤85 years (<80 years: 9.3 months; 80-85 years: 9.5 months) compared with patients >85 years (8.3 months). Median OS was 19.0 months (95% CI, 16.5-21.5) and decreased in the 2 oldest groups (20.6, 17.8, and 13.0 months). Autonomy assessments decreased over time leading to nonconclusive results. Twenty-six percent of patients experienced serious adverse events (SAEs): 7% bevacizumab-related SAEs, and 6% bevacizumab-targeted SAEs. Two fatal bevacizumab-related adverse events were reported (hemorrhagic stroke and intestinal ischemia).

CONCLUSIONS

This large French real-world study showed that medically fit older patients with mCRC could have a benefit/risk balance similar to that of younger patients when treated with first-line bevacizumab plus chemotherapy. Improvements in geriatric assessments are needed to better define this population.

[Chemotherapy of elderly patients with colorectal cancer]

Elderly patients will be the largest group of oncology patients in the future. Because of minimal participation of older patients in randomized clinical trials there is a lack of evidence-based data to make correct decisions with regard to chemotherapy and/or targeted therapy in this age group. Elderly patients have similar benefits from systemic therapies as younger counterparts, but many elders have substantial co-morbidities, which may limit the life expectancy and the effectiveness of systemic therapy. Close collaboration between oncologists and geriatrists will help make decisions on the management of elderly patients suffering from cancer.

Chemotherapy for operable and advanced colorectal cancer

The majority of colorectal cancer patients receive chemotherapy either to palliate advanced unresectable disease or to reduce the risk of recurrence after radical surgery. Thanks to the improvements in systemic chemotherapy, in the last 20 years the median survival time for patients with unresectable metastatic disease has indeed progressively increased from less than 6 to almost 24 months and recurrences after radical surgery in patients with early-stage tumors have been halved. Although colorectal cancer incidence increase with aging, there is limited scientific evidence based on prospective clinical trials to guide the management of elderly colorectal cancer patients. In addition, aging is a continuum process making strict cut-off difficult to define and homogeneous subgroups hard to identify. There is significant heterogeneity also as regards comorbidities, overall physical ability, mental health and functional status. Specific guidelines for the medical treatment of elderly colorectal cancer patients are therefore difficult to draw. While fit patients are generally treated with adult protocols and frail individuals rarely receive chemotherapy, managing the intermediate vulnerable patients requires a careful balance between the biological and psycho-social costs of treatment, the aggressiveness of the tumor and its perception by the patient. In this review, the major achievements of chemotherapy in the treatment of colorectal cancer will be described and the available data addressing the extension of these chemotherapy programs to elderly patients will be discussed. Special emphasis will be given to the development of specific treatment strategies depending on the degree of disease aggressiveness. Empirical suggestions to adapt the chemotherapy programs developed for adult fit patients to subjects with various degrees of vulnerability and frailty will also be given along with practical indications for the use of specific chemotherapeutic agents in the presence of some common elderly-related comorbidities.

Chemotherapy in elderly patients with colorectal cancer

Significant advancements in chemotherapy for metastatic colorectal cancer (mCRC) have been achieved over the past decade, and the median overall survival duration is now close to 24 months with appropriate treatment. The most widely recommended chemotherapy regimens are based on the use of irinotecan or oxaliplatin in combination with 5-fluorouracil and leucovorin; some data suggest further benefit with the addition of the targeted agents bevacizumab or cetuximab. Colorectal cancer primarily affects the elderly; however, much of the defining clinical research in this field has excluded subjects of advanced age or with a poor performance status, making it difficult for clinicians to interpret current treatment paradigms for their older patients. Most clinical trials that have included elderly patients document similar survival rates and toxicity profiles to those seen in younger patients. Moreover, survey data suggest that >70% of elderly patients with cancer are willing to undergo strong, palliative chemotherapy. While these findings suggest that age itself should not determine candidacy for chemotherapy, it is important to note the great heterogeneity of the elderly population with regard to overall health, independence, and performance status. The use of a comprehensive geriatric assessment is recommended to evaluate chemotherapy appropriateness. The management of frail elderly patients and those with a short life expectancy should be focused on palliation, while fit elderly patients can receive aggressive therapy in a similar fashion to younger patients.