Treatment options based on patient characteristics
The majority of metastatic breast cancer patients are over 65 years of age, and therefore a significant proportion are affected by comorbidities such as hypertension, diabetes and respiratory disease [7]. Tolerability of chemotherapy can be profoundly influenced by these comorbidities as well as by their specific treatments.
In the case of elderly patients with significant comorbidities and declining general condition, the aim of treatment is symptomatic control with improvement in quality of life (QoL). To date, the availability of oral agents such as capecitabine and navelbine allows for a good balance between activity, tolerability, compliance and dosage flexibility. Furthermore, weekly administration allows maintenance of the activity of important cytotoxic agents such as taxanes and platinum salts with substantial decrease in toxicity. Finally, new antimetabolites (gemcitabine) or new formulations of old drugs (liposome-encapsulated doxorubicin) are generally associated with reduced toxicity. For these patients it is clear that the best choice is the use of single agents that can be sequentially administered on the basis of tolerability and disease control.
About 20% of patients present with locoregional relapses (regional lymph nodes, skin metastases). Moreover more sensitive imaging techniques (Multislice computed tomography [CT], magnetic resonance imaging [MRI], positron emission tomography [PET] scan) and the development of methods to detect micrometastatic disease (i.e. circulating tumor cells) permit diagnosis of an increasing proportion of patients with oligometastatic disease. A reasonable percentage of these patients can be cured or at least rendered disease free for prolonged period of time; a chemotherapy regimen to induce rapid and important tumor shrinkage followed by locoregional treatments (radiotherapy, surgery, radiofrequency ablation) is necessary to achieve this goal. In this setting, it is clear that combination regimens should be the preferred option.
Another clinical scenario is represented by younger patients, without comorbid conditions, and massive visceral involvement. Here again, rapid tumor shrinkage is important in preventing life-threatening organ failure. In this setting, combination regimens ensure a higher percentage of objective responses [8, 9] and a shorter time to response [10].