A breast cancer diagnosis can be scary. For many, the fear is not just the disease itself but also the possible side effects of cancer treatment.

We spoke with two cancer specialists about the side effects of radiation and chemotherapy — both short and long-term — to get a better understanding of what you can expect from both treatments. Knowledge can help you feel better prepared for treatment, with a better sense of well-being and ownership of your potential cancer journey.

The side effects someone may experience with either chemotherapy or radiation are based on individual factors, including the stage and type of breast cancer and a person's age and current health.

Common side effects of chemotherapy for breast cancer

"With traditional chemotherapy, the most common side effects are hair loss, fatigue and sometimes nausea," says Dr. Veena Chandrakar, a medical oncologist and hematologist with Houston Methodist. "We try to prevent nausea and vomiting through medications."

Chemotherapy kills off rapidly dividing cells, including healthy, noncancerous cells, according to Dr. Chandrakar. Because of this, medical oncologists closely monitor the counts of red and white blood cells and platelets to make sure the levels do not get too low.

Do side effects of chemotherapy get worse with each treatment?

Chemotherapy is administered in cycles over several months. Depending on a person's unique situation, they may undergo four to eight treatment cycles. A cycle can last two to three weeks, usually followed by a brief break before the next cycle begins.

"Side effects for traditional chemotherapy, like hair loss, typically begin around the second or third cycle," Dr. Chandrakar says. "They start noticing their hair falling out or getting follicular pain in their scalp."

For other side effects such as fatigue, Dr. Chandrakar says that each person is different.

"It depends on how healthy they are, their age and health before they start this process of treatments," she says. "Fatigue could be their baseline, but then they could also start getting increasingly tired as the cycles continue."

Dr. Chandrakar notes that emotional exhaustion with the process also can set in as treatment progresses.

"By the time we finish the course, they can be very tired of doing the chemotherapy," Dr. Chandrakar says. "They're just tired of doing the whole process and mentally fatigued — just like 'I'm done with this. When are we going to surgery? What's next?'"

What are the 'hardest days' after receiving chemotherapy?

"Most chemotherapy cycles are approximately every three weeks," Dr. Chandrakar says. "There are some, where we do what is called dose-dense, where we administer it every two weeks. And so, typically, you're more fatigued the three or four days after chemotherapy. They're much more tired the week after specifically. And by the time they build back up on week three, they're ready to start their next cycle."

Dose-dense chemotherapy is usually reserved for patients with an aggressive form of breast cancer. Those completing a dose-dense chemotherapy cycle are more likely to be fatigued. Dr. Chandrakar says that the day after a chemotherapy treatment, patients are given a growth factor treatment, which helps protect white blood cell levels from dropping.

"That shot sometimes causes a lot more side effects than the actual chemotherapy," Dr. Chandrakar says. "It causes a lot of bone pain in some patients. It usually occurs during the first cycle because it's pushing those cells out into the bloodstream to help protect them from infections and keep them out of the hospital."

This bone pain can occur around the third day after treatment in some patients, according to Dr. Chandrakar.

How long does it take to recover from chemotherapy?

Many of the side effects caused by chemotherapy go away any time from a few weeks to a couple of months after the last treatment.

"Chemotherapy-related side effects normalize when they're done with treatment," Dr. Chandrakar says. "The hair does grow back, and the blood counts normalize, assuming that their cancer is not metastatic."

Are there long-term side effects of chemotherapy?

Dr. Chandrakar says that some people may complain of longer-term fatigue and forgetfulness, sometimes called "chemo brain."

She says that recovery time depends on a person's unique situation and that there can be people who bounce back quickly. Others may take a more significant amount of time until they return to normal.

Common side effects of radiation for breast cancer

Radiation treatment is often recommended after breast cancer surgery to help eliminate any microscopic cancer cells that may remain in the breast.

"The treatment consists of an X-ray machine that can move 360 degrees around the patient and shines a targeted flashlight beam of X-ray to the breast area where there is felt to be some risk of microscopic cells being present," says Dr. Peter Morgan, a radiation oncologist with Houston Methodist.

Because radiation is so targeted, Dr. Morgan says that side effects are usually confined to the treated area.

"Radiation does not go to the whole body — it's targeted to the area we need to treat," says Dr. Morgan. "With breast cancer, it is usually only the breast that needs treatment and sometimes the nearby lymph nodes also benefit from treatment."

"During treatment, the most common side effects include slow development of pinkness and sensitivity of the skin in the treatment area, like a mild or medium sunburn," Dr. Morgan says. "We're not talking about a terrible burn, but enough where it bugs the patient a little bit. The skin in the treatment area can also get a little tan in color, looking just like a suntan, and also a little dry."

Patients usually feel mild fatigue during the radiation treatment course, likely due to the energy that the body is using to heal from the treatment each day.

"The X-ray beam targets the breast and leaves the rest of the body alone, but all of the cells in the breast are touched by the X-ray: normal cells and any potential microscopic cancer cells," Dr. Morgan says. "We think that by six hours after each treatment, the normal cells have already healed quite well from the treatment, but cancer cells have a hard time healing.

"So as we give the series of gentle X-ray treatments, the normal cells keep healing well between treatments, but cancer cells in the area get sicker and sicker and die. The healing of the normal cells takes a little energy, so the patient often will feel a little tired during the treatment course."

Dr. Morgan emphasizes that the fatigue experienced during treatment doesn't keep people from going about their normal activities, including work and exercise.

"We're not talking about being totally wiped out," Dr. Morgan says. "They will say, 'You know, I feel like I have 80% or 90% of my normal energy. I'm normally productive until 10 at night and while on treatment I'm running out of gas at 9 at night.'"

Dr. Morgan says a typical course of radiation lasts up to four weeks and includes 19 or 20 treatments. Treatment is given once per day, Monday through Friday. The patient is at the cancer center about 20 minutes per day, but the actual treatment only lasts about two minutes.

How to manage side effects of radiation for breast cancer

Dr. Morgan says that skin-related side effects can be easily managed by applying a moisturizer once a day to help keep the skin happy.

"If the skin sensitivity of the treatment area is bothersome, something as simple as ibuprofen, 200 milligrams twice per day can be helpful," Dr. Morgan says. "Every once in a blue moon, a patient has enough irritation that it makes it hard for them to fall asleep at night, or it's bugging them during their daily activities. In these uncommon scenarios, we will offer a little bit stronger form of pain medicine."

To help weather the mild fatigue experienced during treatment, listen to your body, Dr. Morgan says.

"If you normally do an activity for an hour, and at 40 minutes your body is running out of gas, give yourself permission to pause," Dr. Morgan says. "No big changes in daily activity are typically needed."

When do side effects start with breast radiation?

According to Dr. Morgan, side effects usually begin to slowly appear in the second or third week of treatment.

"Most patients can't even tell they're getting treated in the first week or two, and then gradually, slowly, the side effects show up," Dr. Morgan says. "Usually, the most noticeable side effect is mild to medium skin pinkness and sensitivity. It's very uncommon to have any severe side effects."

How long does it take to recover from radiation?

The most common symptoms, including mild fatigue, skin sensitivity, and sunburn feeling, will go away in two to three weeks after completing treatment, according to Dr. Morgan.

"The tanning and dryness of the skin usually takes a few months to fade, like how a normal suntan would take a few months to fade," Dr. Morgan says.

Are there long-term side effects with breast radiation?

Dr. Morgan says that it is possible for the body to form wispy, internal scar tissue inside the breast treatment area.

"If the body forms this mild wispy scar tissue, the elasticity of the breast can be reduced some," Dr. Morgan says. "It's like there is an internal scaffolding that has formed inside the treated breast that can make it a little bit less soft and squishy. We are not talking about going from a normal soft breast to a hard breast, but a minor change in that direction can be seen."

Dr. Morgan says that a main misconception of radiation side effects is that people think that it will cause the cancer to come back aggressively.

"If part of our normal body is touched by radiation, there may be a small increased risk of a future second malignancy in that area," Dr. Morgan says. "We know that this is true from studies of people who had exposure to radiation that were followed for multiple decades. That increased chance was typically like 3 or 4 out of 1000 — so way less than 1%."

This uncommon future cancer tends to occur 20 to 30 years after the radiation exposure, if it happens at all. Studies showed that these cancers that develop after radiation tend to behave normally (not more aggressively) and respond to standard cancer treatments.

"We have to ask ourselves, 'Why would we ever consider recommending a treatment for cancer if that treatment itself could cause future cancer?'" Dr. Morgan says. "The reason is that the radiation treatment lowers the chance of a breast cancer coming back by 20 or 25 percentage points. But in order to get that 25% risk reduction, we have to accept a less than 1% increase in the risk of a future cancer 20 or 30 years down the road. Thus, the radiation treatment is an overall big benefit for the patient."

What will my breast look like after radiation therapy?

"Most of the time, by six or nine months after radiation therapy, it's hard to tell which breast got the treatment," Dr. Morgan says. "That's because patients heal so well. When patients rate their own cosmetic result and the feel of their treated breast, the great majority feel they have a good or excellent cosmetic result."

Some folks concerned about radiation therapy for their breasts worry about shrinkage of the breast. In fact, a very different phenomenon occurs.

"Often the treated breast better keeps its size and shape after treatment due to the wispy, internal scar tissue support structure that may have formed," Dr. Morgan says. "As time and gravity have their way with the untreated breast, it can look a bit flatter and reside lower on the chest wall."

Over time, this can result in some apparent size and shape differences between the treated and untreated breast. If this asymmetry occurs and is bothersome to the patient, it can often be corrected with future reconstructive surgery, which is typically covered by insurance since it is addressing changes left by the patients' cancer treatment.

Does breast radiation affect the heart or lungs long-term?

"Patients often ask, 'What about my heart? And my lungs?'" Dr. Morgan says. "For us to pass an X-ray beam through the breast, the targeted beam usually has to touch a small part of the lung that is close to the breast. But the good news is that the lung is rarely bothered by that."

Dr Morgan says it is possible for the part of the lung that was touched by the X-ray to get some irritation, called pneumonitis.

Pneumonitis can cause some shortness of breath, a cough and a mild fever. It occurs infrequently, with less than 5% of patients treated with breast radiation experiencing the condition. Dr. Morgan says if pneumonitis were to develop, it can be treated with a multiple week course of oral steroid medication.

"Radiation treatment of the breast is very safe for the lung, and it's even safer than that for the heart," Dr. Morgan says. "When we look at modern studies of radiation for breast cancer, and those patients have been followed for five years or longer after they completed their treatment, we have not seen even a 1% increase in heart problems."

What not to do during chemotherapy or radiation treatment for breast cancer

Dr. Chandrakar says that those in active chemotherapy treatment will want to follow healthy habits.

"I always tell patients to do what they can, but don't overdo it," Dr. Chandrakar says. "You should try to be active, eat balanced meals, avoid drinking alcohol and try to limit exposure to large crowds."

Dr. Morgan emphasizes that there aren't strong precautions for those receiving radiation therapy for breast cancer. However, there are a few recommendations that patients should consider.

"It is OK to be out in the sun during radiation therapy," Dr. Morgan says. "If it is reasonably convenient, I recommend that my patients cover the treatment area if possible. But sometimes that's not convenient, such as when swimming. If the area we're treating will be exposed to the sun, we ask them to apply good sunblock, SPF 30 or higher."

An additional recommendation is to avoid antioxidant supplements while receiving radiation treatment. Dr. Morgan says that antioxidants can be positive for someone's overall health, but during radiation treatment those antioxidants may help cancer cells survive the treatment.

"Radiation hurts cancer cells by causing a little oxidation inside of the cells each day with the idea of eventually killing the cancer cell during the four-week course," Dr. Morgan says. "We don't want a bunch of antioxidant molecules floating around in the cancer cell, ready to help save the cancer cell from the oxidation caused by the treatment."

Dr. Morgan recommends stopping any antioxidant supplements a week before the first radiation treatment. Patients can resume their supplements the day after their radiation therapy has ended. Not sure if your supplement contains antioxidants? Most supplements will say "antioxidant" on the packaging. Vitamins A, C and E and zinc are considered antioxidants, so you would want to pause supplements that include high dosages of them. Dr. Morgan says it's OK for patients to take a multivitamin, but they should cut it back to once a week rather than daily during treatment.

Worried about side effects of chemotherapy or radiation? Talk to your treatment team

You might have heard tales of treatment side effects from someone you know or read about them on social media. Both Dr. Chandrakar and Dr. Morgan say that there can be fear and misconceptions about what happens during and after chemotherapy and radiation.

"There are a lot of preconceived ideas, and anytime someone tells other people about their diagnosis, suddenly everybody's an expert, Dr. Chandrakar says. "All their family and friends are giving them advice about what they should do."

But it's important to remember that another person's experience or the stories you read online doesn't mean the same thing will happen to you. Dr. Chandrakar emphasizes that there are many characteristics to breast cancer, and so many different treatment options that are considered standard of care. Breast cancer is an individual experience — what happened to a loved one or a friend of a friend on social media isn't destined to happen to you.

If you're concerned about side effects or any part of your treatment, it's important to work with your care team to get an understanding of what's bothering you and to get any help you need.

"Many people go through various treatments, and they do very well," Dr. Chandrakar says. "We have lots of medications for controlling side effects like nausea and vomiting. It is our goal to keep you out of the hospital as much as we can, and if you're relatively healthy there should be no reason why you should be hospitalized."