What is the recommended management and surveillance plan for a 70‑year‑old man with a known Lynch‑syndrome mutation who is being followed for prostate cancer and has a prior history of colorectal cancer?

Management of Lynch Syndrome with Prior Colorectal Cancer and Concurrent Prostate Cancer

This 70-year-old man with Lynch syndrome, prior colorectal cancer, and prostate cancer requires intensive ongoing colonoscopic surveillance every 1–2 years, with consideration of annual intervals given his age and prior CRC, while prostate cancer management should follow standard population guidelines as Lynch syndrome does not warrant intensified prostate surveillance. 1

Colorectal Cancer Surveillance Strategy

Continue colonoscopy every 1–2 years indefinitely, as the risk of metachronous colorectal cancer remains substantial even after treatment of the first cancer 2.

• The risk of developing a second colorectal cancer after partial colectomy is approximately 16% at 10 years despite close surveillance 2
• Annual colonoscopy (every 1 year) is specifically advised for males aged 40–60 years due to higher cancer risk, and at age 70 this patient remains at elevated risk 1
• Intensive colonoscopic surveillance reduces colorectal cancer incidence by 62–77% and markedly lowers mortality 1
• Consider chromoendoscopy with dye-spray to improve detection of flat adenomas 1

Critical Consideration: Prior Surgical Extent

If the patient had only partial colectomy for his initial colorectal cancer, discuss the option of completion subtotal colectomy given the 16% 10-year risk of metachronous cancer 2. While functional outcomes are worse after extensive surgery, quality of life is similar between partial and subtotal colectomy 2. This discussion is particularly relevant even at age 70 if the patient has good functional status and life expectancy.

Prostate Cancer Management

Manage the prostate cancer according to standard population guidelines—Lynch syndrome does not warrant intensified prostate cancer surveillance or altered treatment protocols 1.

• While MSH2 mutation carriers have an increased prostate cancer risk (cumulative risk 18% by age 70 for MSH2, versus 8% in general population), the benefit of PSA screening remains unproven due to serious treatment side-effects and indolent course of most screen-detected cancers 2
• Prostate cancers in Lynch syndrome may have higher Gleason scores (8–10), but this does not change the recommendation against routine intensified screening 2
• Follow standard oncologic principles for his existing prostate cancer based on stage, grade, and patient factors

Additional Surveillance Requirements

Urinary Tract Surveillance

Annual urinalysis with cytology is recommended, particularly important given his prior colorectal cancer and depending on his specific MMR gene mutation 1.

• MSH2 carriers have the highest urinary tract cancer risk (6.9%) compared with MLH1 (2.9%) and MSH6 (~1.7%) 1
• This is an inexpensive, easy test that should continue annually 1

Upper Gastrointestinal Surveillance

Upper endoscopy every 3–5 years starting from age 30–35 should have been initiated earlier, but if not yet done, consider catch-up surveillance 1.

• This applies specifically to MLH1, MSH2, or EPCAM mutation carriers 1
• Test for and eradicate Helicobacter pylori if present 1
• Gastric cancer risk ranges from 2–4% in Western populations 1

Other Cancer Screening

Annual physical and neurologic examinations may be offered, though supporting data are limited 1.

Chemoprevention

Strongly recommend daily aspirin (approximately 600 mg) if not contraindicated by bleeding risk or other factors 1.

• At least 2 years of aspirin use reduces colorectal cancer risk by 44–60% in Lynch syndrome 1
• The CAPP2 randomized trial provides Level 1 evidence for this benefit 1
• Adverse-event rates were comparable to placebo in the trial 1
• This is particularly important given his history of colorectal cancer and ongoing high risk

Gene-Specific Risk Stratification

The specific MMR gene mutation matters for risk assessment:

• MLH1/MSH2 carriers: 27–74% colorectal cancer risk by age 70, mean diagnosis age 46–61 years 2
• MSH6 carriers: 10–22% colorectal cancer risk by age 70 (male 22%, female 10%), mean diagnosis age 54–63 years 2, 3
• PMS2 carriers: 15–20% colorectal cancer risk by age 70, mean diagnosis age 47–66 years 2

Critical Pitfalls to Avoid

• Do not reduce surveillance intensity based on age alone—61% of cancer deaths in Lynch syndrome are now from non-colorectal, non-endometrial cancers, emphasizing the need for continued vigilance 2
• Do not assume prostate cancer is Lynch-related or requires different management than sporadic prostate cancer 1
• Do not forget aspirin chemoprevention—this is one of the most evidence-based interventions available 1
• Ensure systematic collection of surveillance data ideally through a Lynch syndrome registry to contribute to ongoing evidence 2