Section 17K. Any coverage offered by the commission to an active or retired employee of the commonwealth insured under the group insurance commission that provides coverage for cancer chemotherapy treatment shall provide coverage for prescribed, orally administered anticancer medications used to kill or slow the growth of cancerous cells on a basis not less favorable than intravenously administered or injected cancer medications that are covered as medical benefits. An increase in patient cost sharing for anticancer medications shall not be allowed to achieve compliance with this section.