Cancer screening-what you should know

MD Anderson Cancer Center
Date: 04-28-2014



Lisa Garvin: Welcome to Cancer Newsline, a podcast series from the University of Texas and the Anderson Cancer Center. Cancer Newsline helps you stay current with the news on cancer research and diagnosis, treatment and prevention providing the latest information on reducing your family's cancer risk. I'm your host Lisa Garvin and today we're going to be talking about cancer screening and some guidelines that the general public can follow. Our guest to address that is Dr. Therese Bevers. She is the Medical Director of MD Anderson's Cancer Prevention Center. Dr. Bevers, what are the standard screenings for cancer that are in place right now and well established?

Dr. Therese Bevers: So, the screening tests that we think about for average risk individuals are for women breast cancer screening and cervical cancer screening. For some men prostate cancer screening and then for both men and women colorectal cancer screening.

Lisa Garvin: Over the years as these screening programs have matured, what sort of impact have we seen on cancer and diagnosis?

Dr. Therese Bevers: So we're seeing that for many of the disease sites cancers are caught earlier when they're more treatable the treatments don't have to be as intensive as they are when they're diagnosed at a more advanced stage. So there's less associated illness from the treatment and fewer people are dying from cancer.

Lisa Garvin: As we move forward in the screening realm, we've taken a big step forward with lung cancer, which is a huge impact on both men and women and recently now we're screening for lung cancer.

Dr. Therese Bevers: Yes, we are. There is data that came out from a large study of high-risk individuals, those who had a 30-pack year smoking history and pack years is the number of packs times the number of years and this trial done at individuals age 55 to 74 demonstrated a 20% reduced rate of dying from lung cancer by obtaining the low dose spiral CT scans. We're hoping because the numbers on lung cancer don't budge much. Generally this is a disease that's caught in later stages and so forth.

Dr. Therese Bevers: Absolutely. And what we're seeing is that by doing this low-dose CT scan we're catching the lung cancers at a very, very tiny size so they're very early and the treatments are more effective. So, again, the treatments are less toxic, less invasive and fewer people are dying from the disease. So we're hoping to actually change the landscape of lung cancer by seeing that it becomes a disease that more people survive from than what is traditionally been the case. That's certainly what we've seen with cases like breast cancer screening and cervical cancer screening, prostate cancer screening.

Lisa Garvin: Now how do people navigate the news? Because if you're paying attention, mammograms go back and forth and back and forth and we have this big Canadian study so how do people navigate that landscape of conflicting information?

Dr. Therese Bevers: Quite frankly it is hard to navigate the landscape of cancer screening and the data that comes out. What we have seen with the recent Canadian National Breast Screening study is that some of the people speaking in support of the trial and questioning the role of mammographic screening are clinicians that are in the field of cancer screening. They clearly don't seem to fully understand the flaws that are associated with that trial. I typically tell my parents that there's some reliable sources. One is the National Cancer Institute. They provide a good outline of the trials, the benefits that were obtained, the harm associated with it and any potential flaws that may have been inherent in the design of the trial. The American Cancer Society is also a good resource and then hopefully they can talk to their clinical but I also know that the clinicians are overwhelmed with the data just as the consumer is.

Lisa Garvin: Let's start with the main standardized screening and let's talk about our recommendations to people. So let's start with breast. What is the MD Anderson recommendation for screening?

Dr. Therese Bevers: So, actually MD Anderson makes risk-based cancer screening recommendations. That means that we provide recommendations based on an individual's level of risk of developing the cancer. So, for average-risk women, we recommend that clinical breast exam and mammogram be done annually beginning at age 40. Now on a woman who is at increased risk, she may need to start earlier and she may need to have additional tests ordered in addition to the mammogram.

Lisa Garvin: After the baseline mammogram how often should they be getting mammograms?

Dr. Therese Bevers: We would recommend annually so we recommend women get breast exam and a mammogram once a year.

Lisa Garvin: What about colorectal cancer? Very common, strikes both genders, what are our recommendations?

Dr. Therese Bevers: For average risk individuals we recommend that they begin screening at age 50. There are a number of modalities that could be chosen from. A common one and one that is preferred by MD Anderson is the colonoscopy. There are two different types of colonoscopy, the conventional colonoscopy but there's also the virtual colonoscopy. The benefits to the colonoscopy is that you can see polyps and with the conventional colonoscopy you can actually remove the polyp thus effectively preventing colon cancer if that polyp was destined to become a colon cancer. Less invasive tests are fecal occult blood tests where the individual does a sampling of their stool on three consecutive specimens, mails that in and it is developed to see if there's blood hidden in the stool. That one is not the preferred modality because we tend to see that lesions bleed only once they become more advanced pre-cancers or actually are a cancer. So we may not have as great of an opportunity to prevent the development of colon cancer. Then again if an individual is at increased risk of colon cancer maybe due to family history, other conditions such as inflammatory bowel disease, they may need to start earlier and do it more frequent than what we typically recommend.

Lisa Garvin: Now for prostate cancer it's kind of like breast cancer in that the PSA test has kind of had conflicting results and conflicting studies. What are recommendations for men for prostate cancer screening?

Dr. Therese Bevers: So first off we recognize that there are benefits but there are also harms associated with any cancer screening and one of them that we see more pronounced harms potentially being associated with it in certain men is prostate cancer screening. So we think the first step of prostate cancer screening is actually that the man needs to be educated on what benefits he may obtain, what are the harms associated with it and he along with his clinician make a very individualized decision of whether screening is appropriate for him. In average-risk individuals, we recommend they begin prostate cancer screening at age 50 but individuals at increased risk based on family history or being African American may need to start earlier as early as age 40.

Lisa Garvin: So for cervical cancer what are the screening guidelines?

Dr. Therese Bevers: So the guidelines have changed significantly from what women have been familiar with of going in every year to get your pap smear. This is largely due to our increased understanding of what causes cervical cancer. We know that it is caused by HPV or Human Papillomavirus. We now recommend that women between age 21 and 29 get a pap smear every 3 years. We don't recommend HPV testing in that population. There's a high rate of infection but a high rate of the woman's immune system completely clearing the infection and it not being an issue, but beginning at age 30, the HPV infection is more likely to be a persistent infection. So we recommend co-testing where a woman gets both pap and HPV testing done and the HPV testing is done actually on the fluid that the Pap smear is placed in. So it's not an additional test to her. If she is negative for both pap and HPV she may go to every 5 years because having a negative HPV is highly predictive for not getting cervical cancer for an extended interval of time. If for some reason she doesn't do co-testing and only gets a pap smear, she should still be screened at the every 3 year interval.

Lisa Garvin: What about women who have had hysterectomies? I know there's a bit of controversy there. If you have had a hysterectomy and no long have a cervix, is a pap important?

Dr. Therese Bevers: Pap may not be important. The only reason we would continue to do pap smears in a woman who has had a hysterectomy where the cervix was removed is if they had high-grade dysplasia or pre-cancer or actually had cervical cancer in which case we would be doing a pap smear to monitor for recurrence, but if they have had not that, if she hadn't had that in the past 20 years, she's not going to benefit from screening of the vaginal cuff.

Lisa Garvin: I know that with ovarian cancer there's a screening test that's kind of teetering on the brink of like being a standard procedure or is it? We're talking about CA125, which is a tumor marker, how is that test bearing out?

Dr. Therese Bevers: So it's not a standard test and it's not recommended by any organization for average-risk women. The only population we even maybe consider doing at the end is women who have a known genetic predisposition and then we're just biding time until she actually has her ovaries removed after she's finished having children. The reason we don't recommend it as a standard test is that these very large screening studies that looked at CA125 actually yielded very disappointing results. We did not see that women who got a CA125 were less likely to die from ovarian cancer than women who did not get the test, but importantly there were significant harms. In some cases, women who had an elevated CA125 had to go to a surgical procedure for the doctor to look at the ovaries to make sure that there wasn't cancer because of that elevated CA125 and there were women who developed post-operative complications some of them quite significant. So, there were significant harms, there's no proven benefit, so it is not recommended for average-risk women. Now having said that there is a great deal of interest in trying to find a test for ovarian cancer screening because we do believe it is a cancer that if it is found early enough we would have more woman surviving the disease. There are studies going on in the US and in Europe looking at not only the CA125 but looking at it in a different way but also looking at a panel of tumor markers. So maybe it's not just the CA125, maybe it's as panel of different tumor markers of which CA125 is only one that may be better able to identify which women actually had the disease and not bring a lot of women who don't have the disease to needing additional testing.

Lisa Garvin: Are there any other cancer screening methods that are being researched and I mean are there any on the horizon?

Dr. Therese Bevers: So certainly for the known diseases that there are tests that we are looking at and a good example is breast cancer screening. Mammography clearly is the gold standards. It's the only test that we have that has been shown to reduce a woman's chance of dying from breast cancer. However, we now are utilizing MRIs in high-risk women as they have been found to find breast cancers in that high-risk population that may not have been seen by mammograms. We're also looking at other types of testing. An exciting one is molecular breast imaging where we actually use a radio nuclide to image the breast and see if we can identify any abnormality in a different way than mammograms or MRI do.
Lisa Garvin: So are there any other diseases where screening methods are being looked into?

Dr. Therese Bevers: So population that has been identified as being at increased risk of cancer are individuals with cirrhosis and they're at increased risk of liver cancer. Now this cirrhosis can come from a number of different factors but commonly we see it as a late sequela of Hepatitis B or Hepatitis C. So not only are we trying to identify individuals that have had Hepatitis B or C infection. For Hepatitis B we're encouraging the immunization to prevent that but now for those high-risk individuals we actually do recommend a screening program of ultrasound and alpha fetoprotein being done.

Lisa Garvin: There are some cancers that we know now has a genetic basis. What is the role of genetic testing in people who have had cancer in their family tree?

Dr. Therese Bevers: So, it's important to understand your full family history of cancer and talking with your physician about whether that may be putting you at risk for having a genetic predisposition to a particular type of cancer. Not everyone needs genetic testing. There are certain criteria that we commonly look at to determine if we need to consider testing or not. For example, if we're looking at the breast and ovarian cancer gene, we're looking for two premenopausal breast cancers on one side of the family or premenopausal breast cancer and ovarian cancer. So we have some specific criteria that we use. Not everybody needs genetic testing, but those individuals who have a family history that may be suggestive of it should talk to their physician about whether genetic testing is appropriate. If we identify an individual as having a genetic predisposition, our recommendations are vastly different from what we provide to an average-risk individual.

Lisa Garvin: So it sounds like the screening methods are there at least for the common cancers. So really the onus is on the individual to kind of follow through.

Dr. Therese Bevers: Absolutely. They need to understand are they at average risk or increased risk of developing a particular cancer. They can work with their physician through a review of their medical history, their family history, their lifestyle, diet, exercise patterns, tobacco use, all of these to understand what their level of risk is. Based on that level of risk, specific cancer screening recommendations can be made.

Lisa Garvin: Great. Thank you. Very good information. If you have questions about anything you've heard today on Cancer Newsline, contact Ask MD Anderson at 1-877-MDA-6789 or online at Thank you for listening to this episode of Cancer Newsline. Tune in for the next podcast in our series.