Geriatric Cancers Present Many Therapeutic Challenges

As the population ages, the number of cancer diagnoses also rises. The risk of developing some form of cancer increases by 44% for men and 38% for women in the geriatric demographic.¹ More concerning is that 56% of all cancer diagnoses occur in patients older than 65, and 70% of all cancer deaths are in this population.¹ However, a growing issue is not related to the number of new diagnoses but to the approaches used to treat them. A patient’s tolerance for treatment regimens is pivotal to therapeutic outcomes. Geriatric treatment regimens should be tailored toward the comorbidities and unique needs of this demographic.

EPIDEMIOLOGY

Cancer can be attributed to a number of risk factors, such as environmental exposure, genetics, and lifestyle choices related to alcohol and tobacco use, diet, and obesity. In addition, diseases such as diabetes, heart disease, and hypertension are more prevalent in aging populations.² Concomitant disease states may influence physicians to use less-intense regimens because of a decline in geriatric metabolic processes, the number of current medications, and long-term survival outcomes.² However, the most common contributor to cancer frequency is age.

Among cancers such as breast, colon, leukemia, lung, and prostate, 55% to 70% of cases are diagnosed in patients ≥65 years, with 59% to 89% suc- cumbing to their illnesses, according to National Institutes of Health statistics (see figure 1).³

A lack of geriatric clinical treatment trials creates another limitation to geriatric patients receiving potentially disease-altering chemotherapy (see figures 2 and 3).⁴ Based on National Comprehensive Cancer Network guidelines, female breast cancer treatment depends on age. Female patients who are premenopausal receive distinct treatment, as opposed to postmenopausal women,⁵ and patients who are younger are expected to have better tolerance to their chemotherapy than elderly or frail patients.

TREATMENT

Geriatric oncology treatment continues to be difficult to navigate. Treatment plans should be individualized and interactive. Because of other comorbidities normally associated with aging, the new American Society of Clinical Oncology guidelines for geriatric oncology now recommend the Comprehensive Geriatric Assessment (CGA) and its components as a multidimensional method to identify potential nononcological and oncological problems (see Table).^6,7

Breast cancer is an example of individualized treatment in geriatric patients, based on information from the International Society of Geriatric Oncology.⁸ Hormone therapy available to patients choosing to circumvent chemotherapy, radiation, and surgery include aromatase inhibitors, such as anastrozole or letrozole, or tamoxifen, a selective estrogen receptor modulator.⁸ Geriatric patients with lung cancer, many of whom are 75 and older, are often unwilling to undergo intense treatment regimens.⁹ If chemotherapy is the desired approach, either the Cancer and Aging Research Group or Chemotherapy Risk Assessment Scale for High-Age Patients Assessment is used to determine chemotherapy toxicity risk.¹⁰ Assessments such as the Geriatric 8 or Vulnerable Elders Survey-13 may be used to estimate patient mortality.¹⁰

CURRENT CLINICAL TRIALS

Although the number of clinical trials involving elderly patients remains small, those show promise. Older patients with cancer have previously been treated based on disease pathology and performance status. However, subjective assessments, such as the CGA, remain a crucial aspect of geriatric oncology.¹⁰ The CGA helps analyze how well a geriatric patient will tolerate potential chemotherapy by assessing “frailty markers,” which include energy and fitness levels, mobility, nutritional status, strength, and physical activity, as outlined by the Association Sud de Recherche en Oncogériatrie study.¹⁰ In February 2019, the National Cancer Institute and Massachusetts General Hospital initiated a clinical trial to improve outcomes and develop optimal care regimens for geriatric patients with gastrointestinal and genitourinary malignancies.¹¹ Although not specifically focusing on developing dose adjustments for certain chemotherapies, current trials appear to be aimed at assisting geriatric patients to better manage their treatments through personalized care and symptom management plans.

CONCLUSION

Geriatric cancer occurrences present many therapeutic challenges beyond the disease itself. These patients usually present with multiple comorbidities, potential medication interactions, and various stages of fragility. The clinician must weave a tapestry of treatment choices to effectively treat cancer without diminishing a patient’s length or quality of life. The targeted treatment plan should be developed with an active interdisciplinary team and patient involvement. With the geriatric oncology patient, comorbid conditions, end-of- life wishes, and type of malignancy are pivotal to treatment outcomes.

Jerry A. Barbee Jr, PharmD, BCPS, CPh and Glenn Schulman, PharmD, MS, BCPS, BCACP, BCGP, BCIDP, are clinical pharmacists in Pensacola, Florida.Matthew Bailey is a PharmD candidate at Auburn University in Alabama and Esther Owusu Bediako is a PharmD candidate at Marshall University in Wayne County, West Virginia.

REFERENCES

• Browner I. Applications in geriatric oncology. Johns Hopkins Medicine website. hopkinsmedicine.org/gec/series/ cancer_aging.html#summary. Accessed June 4, 2019.
• Cancer care decisions for older adults. Cancer.net website. cancer.net/navigating-cancer-care/older-adults/cancer-care-decisions-older-adults. Accessed May 1, 2018.
• National Cancer Institute. Cancer stat facts. Surveillance, Epidemiology, and End Results Program website. seer.cancer.gov/statfacts/. Accessed May 2, 2019.
• Sharpless NE. The challenging landscape of cancer and aging: charting a way forward. National Cancer Institute website. cancer.gov/news-events/cancer-currents-blog/2018/sharpless-aging-cancer-research. Published January 24, 2018. Accessed May 1, 2019.
• Kabakov A. NCCN Invasive Breast Cancer Clinical Practice Guidelines in Oncology. J Natl Compr Canc Netw. 2017;5(3):246. doi: 10.6004/jnccn.2007.0025.
• Cohen HJ. Comprehensive geriatric assessment for patients with cancer. UptoDate website. uptodate.com/contents/comprehensive-geriatric-assessment-for-patients-with-cancer. Updated May 15, 2019. Accessed June 4, 2019.
• Mohile SG, Dale W, Somerfield MR, Hurria A. Practical assessment and management of vulnerabilities in older patients receiving chemotherapy: ASCO Guideline for Geriatric Oncology Summary. J Oncol Pract. 2018;14(7):442-446. doi: 10.1200/jop.18.00180.
• Breast cancer. International Society of Geriatric Oncology website. www.siog.org/content/breast-cancer. Accessed June 4, 2019.
• Fuerst ML. Many elderly lung cancer patients receive no treatment. Cancer Network website. cancernetwork.com/lung-cancer/many-elderly-lung-cancer-patients-receive-no-treatment. Published January 10, 2018. Accessed June 4, 2019.
• Farcet A, de Decker L, Pauly V, et al. Frailty markers and treatment decisions in patients seen in oncogeriatric clinics: results from the ASRO Pilot Study. Plos One. 2016;11(2):e0149732. doi: 10.1371/journal.pone.0149732.
• A Geriatric Oncology Collaborative Care Intervention for Older Adults With Advanced Cancer. clinicaltrials.gov/ct2/show/NCT03721926. Updated March 4, 2019. Accessed June 4, 2019.