This is difficult to answer specifically without further details. There certainly is accumulating evidence that patients with cancer, especially those receiving immunosuppressive chemotherapy, are at greater risk of COVID-19 infection if exposed, and a greater risk of serious and life-threatening complications from COVID-19. There are many situations where chemotherapy can be safely delayed or alternatives like endocrine therapy are effective with lower risk. If the eventual risk from the cancer and the potential benefit from chemotherapy is determined to be greater than the immediate risk of COVID-19 infection and serious complications, then attention moves to reducing the risk of chemotherapy. In patients with documented COVID-19, cancer treatment should only be contemplated under extreme conditions if the cancer is immediately life threatening after full discussion with the patient of the potentially dire consequences. In the interim, there may be effective therapeutic options associated with lower need for clinical contact, eg, oral agents, or with lower risk of serious complications requiring hospitalization, eg, febrile neutropenia. Reduction in chemo dose intensity may be considered when the primary goal of treatment is disease control or life prolongation rather than cure. When immediate full chemotherapy dose/schedule is deemed essential, aggressive supportive care is essential to reduce the risk of serious complications, to reduce the direct risk to the patient, and reduce the need for ED or hospital admission further increasing COVID-19 risk (see interim COVID-19 recommendations from NCCN at NCCN.org altering thresholds for support with myeloid growth factors, transfusions or erythroid stimulating agents and platelet support or use of thrombopoetin https://www.nccn.org/covid-19/pdf/HGF_COVID-19.pdf).

Managing complications as much as possible on an ambulatory basis is essential to reducing both COVID-19 exposure and diversion of severely limited provider resources for managing COVID-infected patients. Telemedicine has enabled much of the interaction with providers to be managed remotely without risky encounters at clinics or hospitals. Managing mild symptoms at home with remote contact with the provider is important. Self administration of growth factors and recommended practices of staying at home, social distancing, masks etc are all important for reducing risk.

However, patients with respiratory symptoms from COVID-19 should not be treated with growth factors which increase inflammatory cytokines also associated with ARDS. Common sense measures of adequate sleep, reasonable exercise, and a healthy diet, along with reducing stress as much as possible in this extremely stressful situation, are all important and may improve the immune response to the coronavirus and other pathogens. The right balance of the current risk from COVID-19 in the immunosuppressed cancer patient in their current environment and the often longer term risk from cancer with chemotherapy delays must be discussed with each patient to come to the best decision for the individual patient. In patients with documented COVID-19, active cancer treatment, eg, surgery, radiation or chemotherapy, should be delayed under nearly all conditions. 

There are at least two published analyses showing increased severity and worse outcome from COVID-19 in cancer patients and recent anti-tumor therapy, like chemotherapy, strongly increases risk of severe events.

1) Liang et al published outcomes of 18 patients with cancer and lab-confirmed COVID-19, 4 had chemotherapy or surgery within a month of infection and Cancer history was highest risk for severe events (ICU admission, intubation, death) at 39%. Patients with cancer deteriorated more rapidly than other patients and had overall poorer outcome. 

Reference: Cancer patients in SARS-CoV-2 infection: a nationwide analysis in China. (Liang W et al., Lancet Oncol 2020)

2) Zhang et al presented analysis of 28 cancer patients with lab-confirmed COVID-19 showing 53% risk of developing severe events (ICU admission, ventilator use, death). More importantly, anti-tumor treatment (chemotherapy, immunotherapy, targeted therapy, radiotherapy or a combination) within 14 days of COVID-19 diagnosis significantly increased risk of such severe events (HR 4.079). Among 6 such patients with recent anti-tumor treatment, 5 patients (83%) developed severe events.

Reference: Clinical characteristics of COVID-19-infected cancer patients: A retrospective case study in three hospitals within Wuhan, China.  (Zhang L et al., Ann Oncol 2020)

Based on the above published retrospective data on limited patients, Cancer therapy in patients infected/suspected COVID-19 should be held until complete resolution of symptoms and the patient is considered recovered. There is no standard way of defining recovery in cancer patients, but we can consider CDC's recovery criteria as below:

All confirmed and suspected coronavirus patients should be symptom-free and test negative for the virus twice within at least 24 hours to be considered recovered. In the absence of testing (non-testing method), if a confirmed or suspected COVID-19 patient is fever-free "without the help of fever-reducing medication" for at least three days, if it has been "at least seven days" since the coronavirus symptoms first appeared, that person can be considered recovered.

Resuming cancer therapy/chemotherapy decision has to be individualized, taking in to consideration factors like a) goal of therapy: curative versus palliative, b) type of therapy: chemotherapy, immunotherapy, targeted therapy, radiotherapy or a combination, c) early in treatment versus late in treatment, d) age and co-morbidities.