Can Chemotherapy and Hormone Therapy Be Given Together?

Chemotherapy and hormone therapy are not usually given together in breast cancer, because they are seen to work against each other. When a patient needs both, hormone therapy follows once chemotherapy is complete. Hormone therapy can, however, be combined with targeted therapy. The sequence is decided by the stage of the disease and by the receptors on the tumour.

These are the treatment rules Dr. Mohit Agarwal, Principal Director & Head Medical Oncology, Fortis Hospital, Shalimar Bagh, New Delhi, India, set out for doctors in answer to their questions on breast cancer and advanced disease. His summary of modern oncology is that treatment is tailored to the individual: the right drug, at the right dose, in the right patient. This article explains the treatments themselves, the prognostic factors that choose between them, and how they are sequenced. How cancer is confirmed and staged beforehand is covered in Can Tumour Markers Screen for Cancer? Biopsy and Staging, and the series overview is in Diagnosis and Detection of Cancer: A Complete Guide.

Modern cancer treatments explained

Modern cancer treatment draws on four tools, chemotherapy, targeted therapy, immunotherapy and radiotherapy, chosen and combined for the individual patient.

Chemotherapy

Chemotherapy is any drug that enters the body and kills cancer cells. Patients often fear it as a kind of poison, and Dr. Agarwal answers with a definition that removes some of the mystery: even drugs commonly used to treat arthritis can act as chemotherapy when given to a patient with cancer. Methotrexate is a familiar example, used at low doses for rheumatoid arthritis and at higher doses against several cancers.

He addresses three common fears directly:

• Is chemotherapy painful? No. In his description, it is painless, given much like intravenous fluids.
• Does it cause long-term side effects? It did, but research has brought them down to a level he describes as negligible. Specific drugs still carry specific long-term risks, such as effects on the heart with some agents, which oncology teams monitor.
• Must patients stay at home on bed rest? No. Many of his patients return to the office the day after treatment.

Chemotherapy can be toxic to people nearby if it is not handled properly. Asked about the risks of working close to chemotherapy, Dr. Agarwal was specific. It should be prepared in a dedicated mixing unit with full precautions, and the staff who give it must be trained in how to handle and administer it. It should never be given by anyone who has not been trained in chemotherapy.

The cost of chemotherapy at partner hospitals is set out on the chemotherapy treatment cost page.

Targeted therapy

Targeted therapy is designed to act on cancer cells. In Dr. Agarwal's description, it identifies a specific target on those cells and hits only them. He describes these drugs as very effective with fewer side effects, with one important limitation: they are not available for every cancer. Whether a patient can receive one depends on whether the tumour carries a target.

Immunotherapy

Immunotherapy directs the patient's own immune system to find and kill cancer cells. Dr. Agarwal calls it the newest form of treatment and the game changer in cancer management, because the body's own immunity begins working against the cancer. These drugs are free of the major side effects of chemotherapy. They have their own side effects, however: by activating the immune system, they can cause inflammation in organs such as the thyroid, lungs, bowel, liver and skin, which needs prompt recognition. The immunotherapy treatment cost page gives the cost range.

Radiotherapy

Radiation treatment has become far more precise. Dr. Agarwal describes image-guided radiotherapy, which uses imaging during treatment to direct the beam and can treat any part of the body in a very specific manner with minimal toxicity. See the radiation therapy cost page for the range of costs.

Breast cancer prognostic factors

Breast cancer prognostic factors fall into three groups in Dr. Agarwal's framework:

1. The patient, his or her own condition.
2. The stage of the disease.
3. The biology of the disease, meaning the receptors present on the tumour.

The receptors are the bridge between prognosis and treatment. Breast cancers are tested for hormone receptors (oestrogen and progesterone receptors) and for HER2, a growth-promoting protein. A tumour with hormone receptors can be treated with hormone therapy. A HER2-positive tumour can be treated with targeted therapy directed at HER2. The receptor profile therefore tells the oncologist both how the disease is likely to behave and which drugs it will respond to.

Breast cancer is also often treated without removing the whole breast. Dr. Agarwal points out that breast conservation, removing only the involved portion of the breast, has shown equivalent effectiveness to complete removal. Breast-conserving surgery is normally followed by radiotherapy to the remaining breast. How surgeons choose between the two operations is set out in Breast Conservation Surgery vs Mastectomy: How to Decide. The costs of both operations are on the breast cancer surgery cost page.

Can chemotherapy and hormone therapy be given together?

As a rule, no. When a patient with breast cancer needs both, Dr. Agarwal explains that they are not usually given together, because they are seen to oppose each other. If both are given, hormone therapy starts after chemotherapy is completed. Hormone therapy, he added, can be combined with targeted therapy and with immunotherapy. In current guidelines, immunotherapy for breast cancer is approved mainly for triple-negative disease, which lacks oestrogen, progesterone and HER2 receptors, so combining it with hormone therapy is not standard practice.

How breast cancer treatment is sequenced

Breast cancer treatment is sequenced around the stage of the disease and the receptors on the tumour: chemotherapy first where it is needed, hormone therapy after it, and radiotherapy where the stage calls for it.

Is radiotherapy still needed after a good response to chemotherapy?

Sometimes. In early breast cancer with involved lymph nodes in the armpit (the axilla), patients receive radiotherapy after chemotherapy to sterilise the local area, eliminating any cancer cells left in the breast region. Whether radiotherapy is needed depends on the individual patient and the stage of the disease. A good response to chemotherapy does not by itself remove the need for it.

Advanced breast cancer in patients over 60

For a patient over 60 with advanced breast cancer, the best treatment depends on the tumour's receptors rather than on age alone. Dr. Agarwal lists the options:

• Chemotherapy, followed by some form of maintenance treatment.
• Targeted therapy, if the tumour is HER2-positive.
• Hormone therapy, if the hormone receptors are positive.
• Immunotherapy, if the patient fits the categories for which it is indicated.

Treating relapse and metastatic disease

Relapse and metastatic disease are treated according to where the cancer has appeared and the biology of the tumour, not by a single standard regimen.

Relapse after successful chemotherapy

If cancer returns after successful chemotherapy, the first question is where. When the relapse is confined to one or two sites and has appeared after a good interval, the patient may be offered repeat surgery or radiation to that area, together with medical treatment chosen according to the biology of the disease. When the relapse is not local, the treatment is medical: chemotherapy, targeted therapy or immunotherapy, depending on the receptors present on the patient's tumour.

Cancer that has already spread

There is no single best treatment for cancer that has metastasised, meaning spread to distant organs. Dr. Agarwal's principle is the same as everywhere else in his practice: it is not one size fits all. The choice depends on which cancer the patient has and which sites it has reached, and treatment may be chemotherapy, immunotherapy or targeted therapy.

Why brain tumours recur

A doctor in the session asked why brain tumours relapse so often compared with other tumours. Dr. Agarwal explained that brain tumours tend to recur when they are high grade. Surgery is the primary treatment, but a complete removal of an infiltrating tumour is nearly impossible in the brain, so high-grade tumours are likely to recur. Some low-grade tumours, such as grade 1 tumours that can be removed completely, can be cured, although most diffuse low-grade gliomas eventually recur.

What this means for the referring doctor

The pattern across every answer is consistent. The stage and the receptor biology decide the treatment, and the order of treatments matters as much as the choice. A primary physician does not need to plan the sequence, but should know enough to explain it to a patient: that hormone therapy usually waits until chemotherapy is finished, that radiotherapy may follow even a good response, and that relapse is not the end of treatment options. The broader shift towards personalised treatment, including genomic testing, is discussed in Dr. Agarwal's later masterclass in Personalised Cancer Treatment: From Chemotherapy to NGS.

The questions on sequencing, relapse, metastatic disease and brain tumours came from doctors in the session; the full exchanges are on the Live Discussion page.